Phenotypic and genetic characterization of Piscirickettsia salmonis from Chilean and Canadian salmonids.

PubMed

Otterlei, Alexander; Brevik, Øyvind J; Jensen, Daniel; Duesund, Henrik; Sommerset, Ingunn; Frost, Petter; Mendoza, Julio; McKenzie, Peter; Nylund, Are; Apablaza, Patricia

2016-03-15

The study presents the phenotypic and genetic characterization of selected P. salmonis isolates from Atlantic salmon and rainbow trout suffering from SRS (salmonid rickettsial septicemia) in Chile and in Canada. The phenotypic characterization of the P. salmonis isolates were based on growth on different agar media (including a newly developed medium), different growth temperatures, antibiotics susceptibility and biochemical tests. This is the first study differentiating Chilean P. salmonis isolates into two separate genetic groups. Genotyping, based on 16S rRNA-ITS and concatenated housekeeping genes grouped the selected isolates into two clades, constituted by the Chilean strains, while the Canadian isolates form a branch in the phylogenetic tree. The latter consisted of two isolates that were different in both genetic and phenotypic characteristics. The phylogenies and the MLST do not reflect the origin of the isolates with respect to host species. The isolates included were heterogeneous in phenotypic tests. The genotyping methods developed in this study provided a tool for separation of P. salmonis isolates into distinct clades. The SRS outbreaks in Chile are caused by minimum two different genetic groups of P. salmonis. This heterogeneity should be considered in future development of vaccines against this bacterium in Chile. Two different strains of P. salmonis, in regards to genetic and phenotypic characteristics, can occur in the same contemporary outbreak of SRS.

Mechanism behind Resistance against the Organophosphate Azamethiphos in Salmon Lice (Lepeophtheirus salmonis)

PubMed Central

Kaur, Kiranpreet; Helgesen, Kari Olli; Bakke, Marit Jørgensen; Horsberg, Tor Einar

2015-01-01

Acetylcholinesterase (AChE) is the primary target for organophosphates (OP). Several mutations have been reported in AChE to be associated with the reduced sensitivity against OP in various arthropods. However, to the best of our knowledge, no such reports are available for Lepeophtheirus salmonis. Hence, in the present study, we aimed to determine the association of AChE(s) gene(s) with resistance against OP. We screened the AChE genes (L. salmonis ace1a and ace1b) in two salmon lice populations: one sensitive (n=5) and the other resistant (n=5) for azamethiphos, a commonly used OP in salmon farming. The screening led to the identification of a missense mutation Phe362Tyr in L. salmonis ace1a, (corresponding to Phe331 in Torpedo californica AChE) in all the samples of the resistant population. We confirmed the potential role of the mutation, with reduced sensitivity against azamethiphos in L. salmonis, by screening for Phe362Tyr in 2 sensitive and 5 resistant strains. The significantly higher frequency of the mutant allele (362Tyr) in the resistant strains clearly indicated the possible association of Phe362Tyr mutation in L. salmonis ace1a with resistance towards azamethiphos. The 3D modelling, short term survival experiments and enzymatic assays further supported the imperative role of Phe362Tyr in reduced sensitivity of L. salmonis for azamethiphos. Based on all these observations, the present study, for the first time, presents the mechanism of resistance in L. salmonis against azamethiphos. In addition, we developed a rapid diagnostic tool for the high throughput screening of Phe362Tyr mutation using High Resolution Melt analysis. PMID:25893248

Caligus fajerae n. sp. (Copepoda: Caligidae) parasitic on the Pacific sierra Scomberomurus sierra Jordan & Starks (Actinopterygii: Scombridae) in the Pacific Ocean off Mexico.

PubMed

Morales-Serna, Francisco Neptalí; Oceguera-Figueroa, Alejandro; Tang, Danny

2017-10-01

A new species of parasitic copepod, Caligus fajerae n. sp. (Caligidae), is described from Scomberomorus sierra Jordan & Starks (Scombridae) caught off the northwestern coast of Mexico. The new species morphologically resembles Caligus cybii Bassett-Smith, 1898, Caligus kanagurta Pillai, 1961, Caligus pelamydis Krøyer, 1863 and Caligus robustus Bassett-Smith, 1898, all of which have been reported from scombrid hosts. Caligus fajerae n. sp. differs from these species by having spinules on the abdomen and caudal ramus, two processes on the proximal antennulary segment, fine striations on the claw of the antenna and maxilliped, a stouter and more recurved maxillulary dentiform process, shorter tines on the sternal furca, two additional patches of spinules on the distal endopodal segment of leg 2, a sclerotised lobe on the anteromedian surface of the leg 3 protopod and serrations on both margins of the first exopodal spine of leg 3. Analysis of the DNA sequences of the mitochondrial cytochrome c oxidase subunit 1 gene for Caligus fajerae n. sp. and 28 congeners, including C. pelamydis and C. robustus, showed that the new species grouped with Caligus belones Krøyer, 1863 (with 20% divergence), a species known to occur predominantly on needlefishes. Caligus fajerae n. sp. is the fifth species of Caligus reported from S. sierra. An updated host-parasite list for Caligus spp. on scombrids is provided.

Identification and Molecular Characterization of Two Acetylcholinesterases from the Salmon Louse, Lepeophtheirus salmonis

PubMed Central

Kaur, Kiranpreet; Bakke, Marit Jørgensen; Nilsen, Frank; Horsberg, Tor Einar

2015-01-01

Acetylcholinesterase (AChE) is an important enzyme in cholinergic synapses. Most arthropods have two genes (ace1 and ace2), but only one encodes the predominant synaptic AChE, the main target for organophosphates. Resistance towards organophosphates is widespread in the marine arthropod Lepeophtheirus salmonis. To understand this trait, it is essential to characterize the gene(s) coding for AChE(s). The full length cDNA sequences encoding two AChEs in L. salmonis were molecularly characterized in this study. The two ace genes were highly similar (83.5% similarity at protein level). Alignment to the L. salmonis genome revealed that both genes were located close to each other (separated by just 26.4 kbp on the L. salmonis genome), resulting from a recent gene duplication. Both proteins had all the typical features of functional AChE and clustered together with AChE-type 1 proteins in other species, an observation that has not been described in other arthropods. We therefore concluded the presence of two versions of ace1 gene in L. salmonis, named ace1a and ace1b. Ace1a was predominantly expressed in different developmental stages compared to ace1b and was possibly active in the cephalothorax, indicating that ace1a is more likely to play the major role in cholinergic synaptic transmission. The study is essential to understand the role of AChEs in resistance against organophosphates in L. salmonis. PMID:25938836

Fauna of Cladocera and Copepoda from Xinjiang Uyghur Autonomous Region (China).

PubMed

Chertoprud, Elena S; Sinev, Artem Y; Dimante-Deimantovica, Inta

2017-05-03

This study evaluates the species composition of Cladocera and Copepoda in the five lakes of the Bogda-Shan Mountain range and in the floodplain of the Tarim and Konchedarya rivers located in the Xinjiang Uygur Autonomous Region of China (Xinjiang). We collected seven species of Cladocera and six species of Copepoda. Seven species were identified as new for Xinjiang fauna, and two species (Cyclops cf. herberti Einsle, 1996, and Eucyclops roseus Ishida, 1997) were first records for China. Herein, we characterize the distribution ranges for the detected species and provide taxonomic remarks. The total species list for water bodies in Xinjiang compiled from original data and available literature includes 56 species of Cladocera and 33 species of Copepoda. We also discuss the biogeographical structure of Cladocera and Copepoda faunas in Xinjiang.

Epizootiology of the ectoparasitic protozoans Ichthyobodo salmonis and Trichodina truttae on wild chum salmon Oncorhynchus keta.

PubMed

Mizuno, Shinya; Urawa, Shigehiko; Miyamoto, Mahito; Saneyoshi, Hayato; Hatakeyama, Makoto; Koide, Nobuhisa; Ueda, Hiroshi

2017-10-18

Infestations of the ectoparasitic flagellate Ichthyobodo salmonis and the ciliate Trichodina truttae have caused acute mortalities of hatchery-reared juvenile chum salmon Oncorhynchus keta in Hokkaido, northern Japan. This study examined the epizootiology of I. salmonis and T. truttae on wild chum salmon as a possible infection source of the 2 parasitic protozoans in hatcheries. Infestations by both ectoparasites were detected on freshwater-adapted adult and juvenile chum salmon in all 4 rivers examined. This is the first study of an anadromous Pacific salmonid to report infestation of I. salmonis and T. truttae in adults returning for spawning. Among the marine-inhabiting phase of chum salmon, infestation with I. salmonis, but not T. truttae, was observed on adults and juveniles. The 2 protozoans were experimentally transmitted at the same time from wild to hatchery-reared chum salmon juveniles, and caused a high rate of mortality in the hatchery fish. In freshwater, the proliferation rate of T. truttae was greater than that of I. salmonis. These observations show that the euryhaline ectoparasite I. salmonis can infest chum salmon throughout their life cycle, in both river and ocean habitats, whereas T. truttae is able to infest these salmonids only in freshwater. Furthermore, wild chum salmon were shown to be a potential infestation source for both T. truttae and I. salmonis in hatchery fish.

The discovery of Caligus macrurus Heller, 1865 (Copepoda: Caligidae) in the Mediterranean Sea, and the recognition of Sciaenophilus van Beneden, 1852 as a junior synonym of Caligus Müller, 1785.

PubMed

Özak, Argun Akif; Yanar, Alper; Boxshall, Geoffrey Allan

2017-01-01

The siphonostomatoid parasitic copepod Caligus macrurus Heller, 1865 is redescribed based on new material collected from the gill filaments and pharynx of tripletail Lobotes surinamensis Bloch (Lobotidae) caught in Iskenderun Bay, Turkey. Key diagnostic characters and newly observed taxonomic features are reported, supported by light and scanning electron microscopy observations. This is the first report of C. macrurus from Mediterranean waters. Caligus macrurus is also recognised as conspecific with the better known Caligus bennetti Causey, 1953, found on the same host, which becomes a junior subjective synonym of C. macrurus. Caligus O.F. Müller, 1785 and Sciaenophilus van Beneden, 1852 have both been treated as valid genera within the family Caligidae although numerous doubts have been expressed over the validity of the latter. The morphological evidence does not support generic level distinction and we recommend the transfer of all species currently placed in Sciaenophilus into Caligus as C. tenuis (van Beneden, 1852), C. pharaonis von Nordmann, 1832, C. nibeae Shen, 1957 and C. macrurus.

Transcriptional response of Atlantic salmon families to Piscirickettsia salmonis infection highlights the relevance of the iron-deprivation defence system.

PubMed

Pulgar, Rodrigo; Hödar, Christian; Travisany, Dante; Zuñiga, Alejandro; Domínguez, Calixto; Maass, Alejandro; González, Mauricio; Cambiazo, Verónica

2015-07-04

Piscirickettsiosis or Salmonid Rickettsial Septicaemia (SRS) is a bacterial disease that has a major economic impact on the Chilean salmon farming industry. Despite the fact that Piscirickettsia salmonis has been recognized as a major fish pathogen for over 20 years, the molecular strategies underlying the fish response to infection and the bacterial mechanisms of pathogenesis are poorly understood. We analysed and compared the head kidney transcriptional response of Atlantic salmon (Salmo salar) families with different levels of susceptibility to P. salmonis infection in order to reveal mechanisms that might confer infection resistance. We ranked forty full-sibling Atlantic salmon families according to accumulated mortality after a challenge with P. salmonis and selected the families with the lowest and highest cumulative mortalities for microarray gene expression analysis. A comparison of the response to P. salmonis infection between low and high susceptibility groups identified biological processes presumably involved in natural resistance to the pathogen. In particular, expression changes of genes linked to cellular iron depletion, as well as low iron content and bacterial load in the head kidney of fish from low susceptibility families, suggest that iron-deprivation is an innate immunity defence mechanism against P. salmonis. To complement these results, we predicted a set of iron acquisition genes from the P. salmonis genome. Identification of putative Fur boxes and expression of the genes under iron-depleted conditions revealed that most of these genes form part of the Fur regulon of P. salmonis. This study revealed, for the first time, differences in the transcriptional response to P. salmonis infection among Atlantic salmon families with varied levels of susceptibility to the infection. These differences correlated with changes in the abundance of transcripts encoding proteins directly and indirectly involved in the immune response; changes that

Lepeophtheirus salmonis: characterization of prostaglandin E(2) in secretory products of the salmon louse by RP-HPLC and mass spectrometry.

PubMed

Fast, M D; Ross, N W; Craft, C A; Locke, S J; MacKinnon, S L; Johnson, S C

2004-01-01

Lepeophtheirus salmonis is an ectoparasitic copepod that causes serious disease outbreaks in both wild and farmed salmonids. As the relationship between L. salmonis and its hosts is not well understood, the current investigation was undertaken to investigate whether any immunomodulatory compounds could be identified from secretions of L. salmonis. By incubating live L. salmonis adults with the neurotransmitter dopamine in seawater, we were able to obtain secretions from the parasite. These were analyzed by RP-HPLC column, as well as LC-MS. L. salmonis secretions contained a compound with the same retention time and mass of PGE(2). The identity of this compound as PGE(2) was confirmed by MS-in source dissociation. The concentrations of PGE(2) in L. salmonis secretions ranged from 0.2 to 12.3 ng/individual and varied with incubation temperature and time kept off the host. Prostaglandin E(2) is a potent vasodilator and thought to aid in parasite evasion from host immune responses. This is the first reported evidence of prostaglandin production in parasitic copepod secretions and its implications for the host-parasite relationship are discussed.

Fast detection of Piscirickettsia salmonis in Salmo salar serum through MALDI-TOF-MS profiling.

PubMed

Olate, Verónica R; Nachtigall, Fabiane M; Santos, Leonardo S; Soto, Alex; Araya, Macarena; Oyanedel, Sandra; Díaz, Verónica; Marchant, Vanessa; Rios-Momberg, Mauricio

2016-03-01

Piscirickettsia salmonis is a pathogenic bacteria known as the aetiological agent of the salmonid rickettsial syndrome and causes a high mortality in farmed salmonid fishes. Detection of P. salmonis in farmed fishes is based mainly on molecular biology and immunohistochemistry techniques. These techniques are in most of the cases expensive and time consuming. In the search of new alternatives to detect the presence of P. salmonis in salmonid fishes, this work proposed the use of MALDI-TOF-MS to compare serum protein profiles from Salmo salar fish, including experimentally infected and non-infected fishes using principal component analysis (PCA). Samples were obtained from a controlled bioassay where S. salar was challenged with P. salmonis in a cohabitation model and classified according to the presence or absence of the bacteria by real time PCR analysis. MALDI spectra of the fish serum samples showed differences in its serum protein composition. These differences were corroborated with PCA analysis. The results demonstrated that the use of both MALDI-TOF-MS and PCA represents a useful tool to discriminate the fish status through the analysis of salmonid serum samples. Copyright © 2016 John Wiley & Sons, Ltd.

A novel liquid medium for the efficient growth of the salmonid pathogen Piscirickettsia salmonis and optimization of culture conditions.

PubMed

Henríquez, Mirtha; González, Ernesto; Marshall, Sergio H; Henríquez, Vitalia; Gómez, Fernando A; Martínez, Irene; Altamirano, Claudia

2013-01-01

Piscirickettsia salmonis is the bacterium that causes Piscirickettsiosis, a systemic disease of salmonid fish responsible for significant economic losses within the aquaculture industry worldwide. The growth of the bacterium for vaccine formulation has been traditionally accomplished by infecting eukaryotic cell lines, a process that involves high production costs and is time-consuming. Recent research has demonstrated that it is possible to culture pure P. salmonis in a blood containing (cell-free) medium. In the present work we demonstrate the growth of P. salmonis in a liquid medium free from blood and serum components, thus establishing a novel and simplified bacteriological medium. Additionally, the new media reported provides improved growth conditions for P. salmonis, where biomass concentrations of approximately 800 mg cell dry weight L(-1) were obtained, about eight times higher than those reported for the blood containing medium. A 2- level full factorial design was employed to evaluate the significance of the main medium components on cell growth and an optimal temperature range of 23-27°C was determined for the microorganism to grow in the novel liquid media. Therefore, these results represent a breakthrough regarding P. salmonis research in order to optimize pure P. salmonis growth in liquid blood and serum free medium.

Ultrastructure and molecular diagnosis of Spironucleus salmonis (Diplomonadida) from rainbow trout Oncorhynchus mykiss in Germany.

PubMed

Fard, M Reza Saghari; Jørgensen, Anders; Sterud, Erik; Bleiss, Wilfrid; Poynton, Sarah L

2007-03-29

Diplomonad flagellates infect a wide range of fish hosts in aquaculture and in the wild in North America, Asia and Europe. Intestinal diplomonad infection in juvenile farmed trout can be associated with morbidity and mortality, and in Germany, diplomonads in trout are commonly reported, and yet are poorly characterised. We therefore undertook a comprehensive study of diplomonads from German rainbow trout Oncorhynchus mykiss, using scanning and transmission electron microscopy, and sequencing of the small subunit (ssu) rRNA gene. The diplomonad was identified as Spironucleus salmonis, formerly reported from Germany as Hexamita salmonis. Our new surface morphology studies showed that the cell surface was unadorned and a caudal projection was present. Transmission electron microscopy facilitated new observations of functional morphology, including vacuoles discharging from the body surface, and multi-lobed apices of the nuclei. We suggest the lobes form, via hydrostatic pressure on the nucleoplasm, in response to the beat of the anterior-medial flagella. The lobes serve to intertwine the nuclei, providing stability in the region of the cell exposed to internal mechanical stress. The ssu rRNA gene sequence clearly distinguished S. salmonis from S. barkhanus, S. salmonicida, and S. vortens from fish, and can be used for identification purposes. A 1405 bp sequence of the ssu rRNA gene from S. salmonis was obtained and included in a phylogenetic analysis of a selection of closely related diplomonads, showing that S. salmonis was recovered as sister taxon to S. vortens.

Comparative Pan-Genome Analysis of Piscirickettsia salmonis Reveals Genomic Divergences within Genogroups.

PubMed

Nourdin-Galindo, Guillermo; Sánchez, Patricio; Molina, Cristian F; Espinoza-Rojas, Daniela A; Oliver, Cristian; Ruiz, Pamela; Vargas-Chacoff, Luis; Cárcamo, Juan G; Figueroa, Jaime E; Mancilla, Marcos; Maracaja-Coutinho, Vinicius; Yañez, Alejandro J

2017-01-01

Piscirickettsia salmonis is the etiological agent of salmonid rickettsial septicemia, a disease that seriously affects the salmonid industry. Despite efforts to genomically characterize P. salmonis , functional information on the life cycle, pathogenesis mechanisms, diagnosis, treatment, and control of this fish pathogen remain lacking. To address this knowledge gap, the present study conducted an in silico pan-genome analysis of 19 P. salmonis strains from distinct geographic locations and genogroups. Results revealed an expected open pan-genome of 3,463 genes and a core-genome of 1,732 genes. Two marked genogroups were identified, as confirmed by phylogenetic and phylogenomic relationships to the LF-89 and EM-90 reference strains, as well as by assessments of genomic structures. Different structural configurations were found for the six identified copies of the ribosomal operon in the P. salmonis genome, indicating translocation throughout the genetic material. Chromosomal divergences in genomic localization and quantity of genetic cassettes were also found for the Dot/Icm type IVB secretion system. To determine divergences between core-genomes, additional pan-genome descriptions were compiled for the so-termed LF and EM genogroups. Open pan-genomes composed of 2,924 and 2,778 genes and core-genomes composed of 2,170 and 2,228 genes were respectively found for the LF and EM genogroups. The core-genomes were functionally annotated using the Gene Ontology, KEGG, and Virulence Factor databases, revealing the presence of several shared groups of genes related to basic function of intracellular survival and bacterial pathogenesis. Additionally, the specific pan-genomes for the LF and EM genogroups were defined, resulting in the identification of 148 and 273 exclusive proteins, respectively. Notably, specific virulence factors linked to adherence, colonization, invasion factors, and endotoxins were established. The obtained data suggest that these genes could be

Comparative Pan-Genome Analysis of Piscirickettsia salmonis Reveals Genomic Divergences within Genogroups

PubMed Central

Nourdin-Galindo, Guillermo; Sánchez, Patricio; Molina, Cristian F.; Espinoza-Rojas, Daniela A.; Oliver, Cristian; Ruiz, Pamela; Vargas-Chacoff, Luis; Cárcamo, Juan G.; Figueroa, Jaime E.; Mancilla, Marcos; Maracaja-Coutinho, Vinicius; Yañez, Alejandro J.

2017-01-01

Piscirickettsia salmonis is the etiological agent of salmonid rickettsial septicemia, a disease that seriously affects the salmonid industry. Despite efforts to genomically characterize P. salmonis, functional information on the life cycle, pathogenesis mechanisms, diagnosis, treatment, and control of this fish pathogen remain lacking. To address this knowledge gap, the present study conducted an in silico pan-genome analysis of 19 P. salmonis strains from distinct geographic locations and genogroups. Results revealed an expected open pan-genome of 3,463 genes and a core-genome of 1,732 genes. Two marked genogroups were identified, as confirmed by phylogenetic and phylogenomic relationships to the LF-89 and EM-90 reference strains, as well as by assessments of genomic structures. Different structural configurations were found for the six identified copies of the ribosomal operon in the P. salmonis genome, indicating translocation throughout the genetic material. Chromosomal divergences in genomic localization and quantity of genetic cassettes were also found for the Dot/Icm type IVB secretion system. To determine divergences between core-genomes, additional pan-genome descriptions were compiled for the so-termed LF and EM genogroups. Open pan-genomes composed of 2,924 and 2,778 genes and core-genomes composed of 2,170 and 2,228 genes were respectively found for the LF and EM genogroups. The core-genomes were functionally annotated using the Gene Ontology, KEGG, and Virulence Factor databases, revealing the presence of several shared groups of genes related to basic function of intracellular survival and bacterial pathogenesis. Additionally, the specific pan-genomes for the LF and EM genogroups were defined, resulting in the identification of 148 and 273 exclusive proteins, respectively. Notably, specific virulence factors linked to adherence, colonization, invasion factors, and endotoxins were established. The obtained data suggest that these genes could be

Comparative evaluation of molecular diagnostic tests for Nucleospora salmonis and prevalence in migrating juvenile salmonids from the Snake River, USA

USGS Publications Warehouse

Badil, Samantha; Elliott, Diane G.; Kurobe, Tomofumi; Hedrick, Ronald P.; Clemens, Kathy; Blair, Marilyn; Purcell, Maureen K.

2011-01-01

Nucleospora salmonis is an intranuclear microsporidian that primarily infects lymphoblast cells and contributes to chronic lymphoblastosis and a leukemia-like condition in a range of salmonid species. The primary goal of this study was to evaluate the prevalence of N. salmonis in out-migrating juvenile hatchery and wild Chinook salmon Oncorhynchus tshawytscha and steelhead O. mykiss from the Snake River in the U.S. Pacific Northwest. To achieve this goal, we first addressed the following concerns about current molecular diagnostic tests for N. salmonis: (1) nonspecific amplification patterns by the published nested polymerase chain reaction (nPCR) test, (2) incomplete validation of the published quantitative PCR (qPCR) test, and (3) whether N. salmonis can be detected reliably from nonlethal samples. Here, we present an optimized nPCR protocol that eliminates nonspecific amplification. During validation of the published qPCR test, our laboratory developed a second qPCR test that targeted a different gene sequence and used different probe chemistry for comparison purposes. We simultaneously evaluated the two different qPCR tests for N. salmonis and found that both assays were highly specific, sensitive, and repeatable. The nPCR and qPCR tests had good overall concordance when DNA samples derived from both apparently healthy and clinically diseased hatchery rainbow trout were tested. Finally, we demonstrated that gill snips were a suitable tissue for nonlethal detection of N. salmonis DNA in juvenile salmonids. Monitoring of juvenile salmonid fish in the Snake River over a 3-year period revealed low prevalence of N. salmonis in hatchery and wild Chinook salmon and wild steelhead but significantly higher prevalence in hatchery-derived steelhead. Routine monitoring of N. salmonis is not performed for all hatchery steelhead populations. At present, the possible contribution of this pathogen to delayed mortality of steelhead has not been determined.

Apoptosis inhibition of Atlantic salmon (Salmo salar) peritoneal macrophages by Piscirickettsia salmonis.

PubMed

Díaz, S; Rojas, M E; Galleguillos, M; Maturana, C; Smith, P I; Cifuentes, F; Contreras, I; Smith, P A

2017-12-01

To improve the understanding of the piscirickettsiosis pathogenesis, the in vivo apoptosis modulation of peritoneal macrophages and lymphocytes was studied in juvenile Salmo salar intraperitoneally injected with Piscirickettsia salmonis. Five fish were sampled at post-exposure days 1, 5, 8 (preclinical), 20 (clinical) and 40 (post-clinical period of the disease), and the leucocytes of their coelomic washings were analysed by flow cytometry (using the JC-1 cationic dye), TUNEL and cytology to detect apoptotic cells. A selective and temporal pattern of apoptosis modulation by P. salmonis infection was observed. Apoptosis in lymphocytes was not affected, whereas it was inhibited in macrophages but only during the preclinical stage of the induced piscirickettsiosis. Hence, it is postulated that P. salmonis inhibits macrophage apoptosis at the beginning of the disease development to survive, multiply and probably be transported inside these phagocytes; once this process is complete, macrophage apoptosis is no longer inhibited, thus facilitating the exit of the bacteria from the infected cells for continuing their life cycle. © 2017 John Wiley & Sons Ltd.

Selection and validation of reliable housekeeping genes to evaluate Piscirickettsia salmonis gene expression.

PubMed

Flores-Herrera, Patricio; Arredondo-Zelada, Oscar; Marshall, Sergio H; Gómez, Fernando A

2018-06-01

Piscirickettsia salmonis is a highly aggressive facultative intracellular bacterium that challenges the sustainability of Chilean salmon production. Due to the limited knowledge of its biology, there is a need to identify key molecular markers that could help define the pathogenic potential of this bacterium. We think a model system should be implemented that efficiently evaluates the expression of putative bacterial markers by using validated, stable, and highly specific housekeeping genes to properly select target genes, which could lead to identifying those responsible for infection and disease induction in naturally infected fish. Here, we selected a set of validated reference or housekeeping genes for RT-qPCR expression analyses of P. salmonis under different growth and stress conditions, including an in vitro infection kinetic. After a thorough screening, we selected sdhA as the most reliable housekeeping gene able to represent stable and highly specific host reference genes for RT-qPCR-driven P. salmonis analysis. Copyright © 2018. Published by Elsevier B.V.

In vitro culture of the flagellate protozoan Hexamita salmonis

USGS Publications Warehouse

Uzmann, J.R.; Hayduk, S.H.

1963-01-01

Trophozoites of Hexamita salmonis, asserted pathogen of juvenile salmonid fishes, were isolated from two species of Pacific salmon hosts and cultured repeatedly in an organic medium saturated with nitrogen. Primary isolates and serial subcultures usually exhibited five- to tenfold population increases per passage.

Sea lice, Lepeophtheirus salmonis, transfer between wild sympatric adult and juvenile salmon on the north coast of British Columbia, Canada.

PubMed

Gottesfeld, A S; Proctor, B; Rolston, L D; Carr-Harris, C

2009-01-01

We examine sea lice, Lepeophtheirus salmonis, on juvenile and adult salmon from the north coast of British Columbia between 2004 and 2006 in an area that does not at present contain salmon farms. There is a pronounced zonation in the abundance of L. salmonis on juvenile pink salmon, Oncorhynchus gorbuscha, in the Skeena and Nass estuaries. Abundances in the proximal and distal zones of these estuaries are 0.01 and 0.05 respectively. The outer zones serve as feeding and staging areas for the pink salmon smolts. Returning Chinook, Oncorhynchus tshawytscha, and coho salmon, Oncorhynchus kisutch, concentrate in these areas. We collected data in 2006 to examine whether L. salmonis on returning adult salmon are an important source of the sea lice that appear on juvenile pink salmon. Nearly all (99%) of the sea lice on returning Chinook and over 80% on coho salmon were L. salmonis. Most of the L. salmonis were motile stages including many ovigerous females. There was a sharp increase in the abundance of sea lice on juvenile pink salmon smolts between May and July 2006 near the sites of adult captures. As there are no salmon farms on the north coast, few sticklebacks, Gasterosteus aculeatus, and very few resident salmonids until later in the summer, it seems that the most important reservoir of L. salmonis under natural conditions is returning adult salmon. This natural source of sea lice results in levels of abundance that are one or two orders of magnitude lower than those observed on juvenile pink salmon in areas with salmon farms such as the Broughton Archipelago.

In sílico identification and characterization of putative Dot/Icm secreted virulence effectors in the fish pathogen Piscirickettsia salmonis.

PubMed

Labra, Álvaro; Arredondo-Zelada, Oscar; Flores-Herrera, Patricio; Marshall, Sergio H; Gómez, Fernando A

2016-03-01

Piscirickettsia salmonis seriously affects the Chilean salmon industry. The bacterium is phylogenetically related to Legionella pneumophila and Coxiella burnetii, sharing a Dot/Icm secretion system with them. Although it is well documented that L. pneumophila and C. burnetii secrete different virulence effectors via this Dot/Icm system in order to attenuate host cell responses, to date there have been no reported virulence effectors secreted by the Dot/Icm system of P. salmonis. Using several annotations of P. salmonis genome, here we report an in silico analyses of 4 putative Dot/Icm effectors. Three of them contain ankyrin repeat domains and the typical conserved 3D structures of this protein family. The fourth one is highly similar to one of the Dot/Icm-dependent effectors of L. pneumophila. Additionally, all the potential P. salmonis effectors contain a classical Dot/Icm secretion signal in their C-terminus, consisting of: an E-Block, a hydrophobic residue in -3 or -4 and an electronegative charge. Finally, qPCR analysis demonstrated that these proteins are overexpressed early in infection, perhaps contributing to the generation of a replicative vacuole, a key step in the neutralizing strategy proposed for the Dot/Icm system. In summary, this report identifies four Dot/Icm-dependent effectors in P. salmonis. Copyright © 2015 Elsevier Ltd. All rights reserved.

Iron metabolism modulation in Atlantic salmon infested with the sea lice Lepeophtheirus salmonis and Caligus rogercresseyi: A matter of nutritional immunity?

PubMed

Valenzuela-Muñoz, Valentina; Gallardo-Escárate, Cristian

2017-01-01

Sea lice are copepodid ectoparasites that produce high economic losses and environmental issues, thus impacting the salmon aquaculture worldwide. Atlantic salmon (Salmo salar) from Northern and Southern Hemispheres are primarily parasitized by Lepeophtheirus salmonis and Caligus rogercresseyi, respectively. To cope L. salmonis infestation, studies suggest that Atlantic salmon can restrict iron availability as a mechanism of nutritional immunity. However, no molecular studies of iron regulation from salmonids infected with C. rogercresseyi have been reported. The aim of this study was to determine if there are differences in the regulation of iron metabolism in Atlantic salmon infested with L. salmonis or C. rogercresseyi. For comparisons, skin and head kidney were profiled using qPCR of 15 genes related to iron regulation in Atlantic salmons infected with each sea louse species in Norway and Chile, respectively. Prior to infestation, no significant differences were observed between fish group. However, genes involved in iron transport and Heme biosynthesis were highly upregulated in Atlantic salmon infested with L. salmonis. Interestingly, hepcidin and Heme oxygenase, a component of the Heme degradation pathway, were upregulated during C. rogercresseyi infestation. Oxidative stress related genes were also evaluated, showing higher transcription activity in the head kidney than in the skin of Atlantic salmon infested with L. salmonis. These comparative results suggest pathogen-specific responses in infected Atlantic salmon, where iron metabolism is primarily regulated during the infestation with L. salmonis than C. rogercresseyi. Feeding behavior, for instance haematophagy, of the infesting sea lice species in relation to iron modulation is discussed. Copyright © 2016 Elsevier Ltd. All rights reserved.

High level efficacy of lufenuron against sea lice (Lepeophtheirus salmonis) linked to rapid impact on moulting processes.

PubMed

Poley, Jordan D; Braden, Laura M; Messmer, Amber M; Igboeli, Okechukwu O; Whyte, Shona K; Macdonald, Alicia; Rodriguez, Jose; Gameiro, Marta; Rufener, Lucien; Bouvier, Jacques; Wadowska, Dorota W; Koop, Ben F; Hosking, Barry C; Fast, Mark D

2018-03-13

Drug resistance in the salmon louse Lepeophtheirus salmonis is a global issue for Atlantic salmon aquaculture. Multiple resistance has been described across most available compound classes with the exception of the benzoylureas. To target this gap in effective management of L. salmonis and other species of sea lice (e.g. Caligus spp.), Elanco Animal Health is developing an in-feed treatment containing lufenuron (a benzoylurea) to be administered prior to seawater transfer of salmon smolts and to provide long-term protection of salmon against sea lice infestations. Benzoylureas disrupt chitin synthesis, formation, and deposition during all moulting events. However, the mechanism(s) of action are not yet fully understood and most research completed to date has focused on insects. We exposed the first parasitic stage of L. salmonis to 700 ppb lufenuron for three hours and observed over 90% reduction in survival to the chalimus II life stage on the host, as compared to vehicle controls. This agrees with a follow up in vivo administration study on the host, which showed >95% reduction by the chalimus I stage. Transcriptomic responses of salmon lice exposed to lufenuron included genes related to moulting, epithelial differentiation, solute transport, and general developmental processes. Global metabolite profiles also suggest that membrane stability and fluidity is impacted in treated lice. These molecular signals are likely the underpinnings of an abnormal moulting process and cuticle formation observed ultrastructurally using transmission electron microscopy. Treated nauplii-staged lice exhibited multiple abnormalities in the integument, suggesting that the coordinated assembly of the epi- and procuticle is impaired. In all cases, treatment with lufenuron had rapid impacts on L. salmonis development. We describe multiple experiments to characterize the efficacy of lufenuron on eggs, larvae, and parasitic stages of L. salmonis, and provide the most comprehensive

Transcriptomic responses to emamectin benzoate in Pacific and Atlantic Canada salmon lice Lepeophtheirus salmonis with differing levels of drug resistance.

PubMed

Sutherland, Ben J G; Poley, Jordan D; Igboeli, Okechukwu O; Jantzen, Johanna R; Fast, Mark D; Koop, Ben F; Jones, Simon R M

2015-02-01

Salmon lice Lepeophtheirus salmonis are an ecologically and economically important parasite of wild and farmed salmon. In Scotland, Norway, and Eastern Canada, L. salmonis have developed resistance to emamectin benzoate (EMB), one of the few parasiticides available for salmon lice. Drug resistance mechanisms can be complex, potentially differing among populations and involving multiple genes with additive effects (i.e., polygenic resistance). Indicators of resistance development may enable early detection and countermeasures to avoid the spread of resistance. Here, we collect sensitive Pacific L. salmonis and sensitive and resistant Atlantic L. salmonis from salmon farms, propagate in laboratory (F1), expose to EMB in bioassays, and evaluate either baseline (Atlantic only) or induced transcriptomic differences between populations. In all populations, induced responses were minor and a cellular stress response was not identified. Pacific lice did not upregulate any genes in response to EMB, but downregulated degradative enzymes and transport proteins at 50 ppb EMB. Baseline differences between sensitive and now resistant Atlantic lice were much greater than responses to exposures. All resistant lice overexpressed degradative enzymes, and resistant males, the most resistant group, overexpressed collagenases to the greatest extent. These results indicate an accumulation of baseline expression differences related to resistance.

Transcriptomic responses to emamectin benzoate in Pacific and Atlantic Canada salmon lice Lepeophtheirus salmonis with differing levels of drug resistance

PubMed Central

Sutherland, Ben J G; Poley, Jordan D; Igboeli, Okechukwu O; Jantzen, Johanna R; Fast, Mark D; Koop, Ben F; Jones, Simon R M

2015-01-01

Salmon lice Lepeophtheirus salmonis are an ecologically and economically important parasite of wild and farmed salmon. In Scotland, Norway, and Eastern Canada, L. salmonis have developed resistance to emamectin benzoate (EMB), one of the few parasiticides available for salmon lice. Drug resistance mechanisms can be complex, potentially differing among populations and involving multiple genes with additive effects (i.e., polygenic resistance). Indicators of resistance development may enable early detection and countermeasures to avoid the spread of resistance. Here, we collect sensitive Pacific L. salmonis and sensitive and resistant Atlantic L. salmonis from salmon farms, propagate in laboratory (F1), expose to EMB in bioassays, and evaluate either baseline (Atlantic only) or induced transcriptomic differences between populations. In all populations, induced responses were minor and a cellular stress response was not identified. Pacific lice did not upregulate any genes in response to EMB, but downregulated degradative enzymes and transport proteins at 50 ppb EMB. Baseline differences between sensitive and now resistant Atlantic lice were much greater than responses to exposures. All resistant lice overexpressed degradative enzymes, and resistant males, the most resistant group, overexpressed collagenases to the greatest extent. These results indicate an accumulation of baseline expression differences related to resistance. PMID:25685190

Disease Resistance in Atlantic Salmon (Salmo salar): Coinfection of the Intracellular Bacterial Pathogen Piscirickettsia salmonis and the Sea Louse Caligus rogercresseyi

PubMed Central

Lhorente, Jean Paul; Gallardo, José A.; Villanueva, Beatriz; Carabaño, María J.; Neira, Roberto

2014-01-01

Background Naturally occurring coinfections of pathogens have been reported in salmonids, but their consequences on disease resistance are unclear. We hypothesized that 1) coinfection of Caligus rogercresseyi reduces the resistance of Atlantic salmon to Piscirickettsia salmonis; and 2) coinfection resistance is a heritable trait that does not correlate with resistance to a single infection. Methodology In total, 1,634 pedigreed Atlantic salmon were exposed to a single infection (SI) of P. salmonis (primary pathogen) or coinfection with C. rogercresseyi (secondary pathogen). Low and high level of coinfection were evaluated (LC = 44 copepodites per fish; HC = 88 copepodites per fish). Survival and quantitative genetic analyses were performed to determine the resistance to the single infection and coinfections. Main Findings C. rogercresseyi significantly increased the mortality in fish infected with P. salmonis (SI mortality = 251/545; LC mortality = 544/544 and HC mortality = 545/545). Heritability estimates for resistance to P. salmonis were similar and of medium magnitude in all treatments (h 2 SI = 0.23±0.07; h 2 LC = 0.17±0.08; h 2 HC = 0.24±0.07). A large and significant genetic correlation with regard to resistance was observed between coinfection treatments (rg LC-HC = 0.99±0.01) but not between the single and coinfection treatments (rg SI-LC = −0.14±0.33; rg SI-HC = 0.32±0.34). Conclusions/Significance C. rogercresseyi, as a secondary pathogen, reduces the resistance of Atlantic salmon to the pathogen P. salmonis. Resistance to coinfection of Piscirickettsia salmonis and Caligus rogercresseyi in Atlantic salmon is a heritable trait. The absence of a genetic correlation between resistance to a single infection and resistance to coinfection indicates that different genes control these processes. Coinfection of different pathogens and resistance to coinfection needs to be considered in future research on

Disease resistance in Atlantic salmon (Salmo salar): coinfection of the intracellular bacterial pathogen Piscirickettsia salmonis and the sea louse Caligus rogercresseyi.

PubMed

Lhorente, Jean Paul; Gallardo, José A; Villanueva, Beatriz; Carabaño, María J; Neira, Roberto

2014-01-01

Naturally occurring coinfections of pathogens have been reported in salmonids, but their consequences on disease resistance are unclear. We hypothesized that 1) coinfection of Caligus rogercresseyi reduces the resistance of Atlantic salmon to Piscirickettsia salmonis; and 2) coinfection resistance is a heritable trait that does not correlate with resistance to a single infection. In total, 1,634 pedigreed Atlantic salmon were exposed to a single infection (SI) of P. salmonis (primary pathogen) or coinfection with C. rogercresseyi (secondary pathogen). Low and high level of coinfection were evaluated (LC = 44 copepodites per fish; HC = 88 copepodites per fish). Survival and quantitative genetic analyses were performed to determine the resistance to the single infection and coinfections. C. rogercresseyi significantly increased the mortality in fish infected with P. salmonis (SI mortality = 251/545; LC mortality = 544/544 and HC mortality = 545/545). Heritability estimates for resistance to P. salmonis were similar and of medium magnitude in all treatments (h2SI = 0.23 ± 0.07; h2LC = 0.17 ± 0.08; h2HC = 0.24 ± 0.07). A large and significant genetic correlation with regard to resistance was observed between coinfection treatments (rg LC-HC = 0.99 ± 0.01) but not between the single and coinfection treatments (rg SI-LC = -0.14 ± 0.33; rg SI-HC = 0.32 ± 0.34). C. rogercresseyi, as a secondary pathogen, reduces the resistance of Atlantic salmon to the pathogen P. salmonis. Resistance to coinfection of Piscirickettsia salmonis and Caligus rogercresseyi in Atlantic salmon is a heritable trait. The absence of a genetic correlation between resistance to a single infection and resistance to coinfection indicates that different genes control these processes. Coinfection of different pathogens and resistance to coinfection needs to be considered in future research on salmon farming, selective breeding and conservation.

Maternal inheritance of deltamethrin resistance in the salmon louse Lepeophtheirus salmonis (Krøyer) is associated with unique mtDNA haplotypes

PubMed Central

Carmona-Antoñanzas, Greta; Bekaert, Michaël; Humble, Joseph L.; Boyd, Sally; Roy, William; Bassett, David I.; Houston, Ross D.; Gharbi, Karim

2017-01-01

Parasitic infections by the salmon louse, Lepeophtheirus salmonis (Krøyer), cause huge economic damage in salmon farming in the northern hemisphere, with combined treatment costs and production losses in 2014 having been estimated at US$ 350 million for Norway (annual production 1.25 million tonnes). The control of L. salmonis relies significantly on medicinal treatments, supplemented by non-pharmacological approaches. However, efficacy losses have been reported for several delousing agents, including the pyrethroid deltamethrin. The aim of the present study was to analyse the genetic basis of deltamethrin resistance in L. salmonis. Deltamethrin median effective concentrations (EC50) were 0.28 μg L-1 in the drug susceptible L. salmonis strain IoA-00 and 40.1 μg L-1 in the pyrethroid resistant strain IoA-02. IoA-00 and IoA-02 were crossed to produce families spanning one parental and three filial generations (P0, F1-F3). In three families derived from P0 crosses between an IoA-00 sire and an IoA-02 dam, 98.8% of F2 parasites (n = 173) were resistant, i.e. remained unaffected after exposure to 2.0 μg L-1 deltamethrin. F3 parasites from these crosses showed a deltamethrin EC50 of 9.66 μg L-1. In two families of the inverse orientation at P0 (IoA-02 sire x IoA-00 dam), 16.7% of F2 parasites were resistant (n = 84), while the deltamethrin EC50 in F3 animals was 0.26 μg L-1. The results revealed a predominantly maternal inheritance of deltamethrin resistance. The 15,947-nt mitochondrial genome was sequenced and compared among six unrelated L. salmonis strains and parasites sampled from wild salmon in 2010. IoA-02 and three further deltamethrin resistant strains, established from isolates originating from different regions of Scotland, showed almost identical mitochondrial haplotypes. In contrast, the mitochondrial genome was variable among susceptible strains and L. salmonis from wild hosts. Deltamethrin caused toxicity and depletion of whole body ATP levels in Io

Phylogenomic analysis of Copepoda (Arthropoda, Crustacea) reveals unexpected similarities with earlier proposed morphological phylogenies.

PubMed

Eyun, Seong-Il

2017-01-19

Copepods play a critical role in marine ecosystems but have been poorly investigated in phylogenetic studies. Morphological evidence supports the monophyly of copepods, whereas interordinal relationships continue to be debated. In particular, the phylogenetic position of the order Harpacticoida is still ambiguous and inconsistent among studies. Until now, a small number of molecular studies have been done using only a limited number or even partial genes and thus there is so far no consensus at the order-level. This study attempted to resolve phylogenetic relationships among and within four major copepod orders including Harpacticoida and the phylogenetic position of Copepoda among five other crustacean groups (Anostraca, Cladocera, Sessilia, Amphipoda, and Decapoda) using 24 nuclear protein-coding genes. Phylogenomics has confirmed the monophyly of Copepoda and Podoplea. However, this study reveals surprising differences with the majority of the copepod phylogenies and unexpected similarities with postembryonic characters and earlier proposed morphological phylogenies; More precisely, Cyclopoida is more closely related to Siphonostomatoida than to Harpacticoida which is likely the most basally-branching group of Podoplea. Divergence time estimation suggests that the origin of Harpacticoida can be traced back to the Devonian, corresponding well with recently discovered fossil evidence. Copepoda has a close affinity to the clade of Malacostraca and Thecostraca but not to Branchiopoda. This result supports the hypothesis of the newly proposed clades, Communostraca, Multicrustacea, and Allotriocarida but further challenges the validity of Hexanauplia and Vericrustacea. The first phylogenomic study of Copepoda provides new insights into taxonomic relationships and represents a valuable resource that improves our understanding of copepod evolution and their wide range of ecological adaptations.

Inhibitory activity of (E)-5-(2-bromovinyl)-2'-deoxyuridine on the salmonid herpesviruses, Oncorhynchus masou virus (OMV) and Herpesvirus salmonis.

PubMed

Kimura, T; Nishizawa, T; Yoshimizu, M; De Clercq, E

1988-01-01

The highly potent and selective anti-herpesvirus agent, (E)-5-(2-bromovinyl)-2'deoxyuridine (BVdU), was examined for its inhibitory effect on the salmonid herpesviruses Oncorhynchus masou virus (OMV) and Herpesvirus salmonis (H. salmonis). Minimum inhibitory concentrations (MIC) of BVdU for OMV and H. salmonis were 1.25 and 3.0 micrograms/ml, respectively; these values were equal to or higher than those obtained for acyclovir or cytarabine. OMV DNA polymerase activity was reduced in a dose-dependent fashion by BVdU 5'-triphosphate (BVdUTP) within the concentration range of 3 to 30 microM. However, BVdUTP could also be substituted for the natural substrate, TTP, in the OMV DNA polymerase assay. It is postulated that the inhibitory action of BVdU on the salmonid herpesviruses is more or less similar to that on other herpesviruses and resides with respect to the inhibition of the virus DNA polymerase activity as well as incorporation of BVdU into the viral DNA.

Genomic Predictions and Genome-Wide Association Study of Resistance Against Piscirickettsia salmonis in Coho Salmon (Oncorhynchus kisutch) Using ddRAD Sequencing

PubMed Central

Barría, Agustín; Christensen, Kris A.; Yoshida, Grazyella M.; Correa, Katharina; Jedlicki, Ana; Lhorente, Jean P.; Davidson, William S.; Yáñez, José M.

2018-01-01

Piscirickettsia salmonis is one of the main infectious diseases affecting coho salmon (Oncorhynchus kisutch) farming, and current treatments have been ineffective for the control of this disease. Genetic improvement for P. salmonis resistance has been proposed as a feasible alternative for the control of this infectious disease in farmed fish. Genotyping by sequencing (GBS) strategies allow genotyping of hundreds of individuals with thousands of single nucleotide polymorphisms (SNPs), which can be used to perform genome wide association studies (GWAS) and predict genetic values using genome-wide information. We used double-digest restriction-site associated DNA (ddRAD) sequencing to dissect the genetic architecture of resistance against P. salmonis in a farmed coho salmon population and to identify molecular markers associated with the trait. We also evaluated genomic selection (GS) models in order to determine the potential to accelerate the genetic improvement of this trait by means of using genome-wide molecular information. A total of 764 individuals from 33 full-sib families (17 highly resistant and 16 highly susceptible) were experimentally challenged against P. salmonis and their genotypes were assayed using ddRAD sequencing. A total of 9,389 SNPs markers were identified in the population. These markers were used to test genomic selection models and compare different GWAS methodologies for resistance measured as day of death (DD) and binary survival (BIN). Genomic selection models showed higher accuracies than the traditional pedigree-based best linear unbiased prediction (PBLUP) method, for both DD and BIN. The models showed an improvement of up to 95% and 155% respectively over PBLUP. One SNP related with B-cell development was identified as a potential functional candidate associated with resistance to P. salmonis defined as DD. PMID:29440129

Molecular Phylogeny and Revision of Copepod Orders (Crustacea: Copepoda).

PubMed

Khodami, Sahar; McArthur, J Vaun; Blanco-Bercial, Leocadio; Martinez Arbizu, Pedro

2017-08-22

For the first time, the phylogenetic relationships between representatives of all 10 copepod orders have been investigated using 28S and 18S rRNA, Histone H3 protein and COI mtDNA. The monophyly of Copepoda (including Platycopioida Fosshagen, 1985) is demonstrated for the first time using molecular data. Maxillopoda is rejected, as it is a polyphyletic group. The monophyly of the major subgroups of Copepoda, including Progymnoplea Lang, 1948 (=Platycopioida); Neocopepoda Huys and Boxshall, 1991; Gymnoplea Giesbrecht, 1892 (=Calanoida Sars, 1903); and Podoplea Giesbrecht, 1892, are supported in this study. Seven copepod orders are monophyletic, including Platycopioida, Calanoida, Misophrioida Gurney, 1933; Monstrilloida Sars, 1901; Siphonostomatoida Burmeister, 1834; Gelyelloida Huys, 1988; and Mormonilloida Boxshall, 1979. Misophrioida (=Propodoplea Lang, 1948) is the most basal Podoplean order. The order Cyclopoida Burmeister, 1835, is paraphyletic and now encompasses Poecilostomatoida Thorell, 1859, as a sister to the family Schminkepinellidae Martinez Arbizu, 2006. Within Harpacticoida Sars, 1903, both sections, Polyarthra Lang, 1948, and Oligoarthra Lang, 1948, are monophyletic, but not sister groups. The order Canuelloida is proposed while maintaining the order Harpacticoida s. str. (Oligoarthra). Cyclopoida, Harpacticoida and Cyclopinidae are redefined, while Canuelloida ordo. nov., Smirnovipinidae fam. nov. and Cyclopicinidae fam. nov are proposed as new taxa.

Genome-wide association analysis reveals loci associated with resistance against Piscirickettsia salmonis in two Atlantic salmon (Salmo salar L.) chromosomes.

PubMed

Correa, Katharina; Lhorente, Jean P; López, María E; Bassini, Liane; Naswa, Sudhir; Deeb, Nader; Di Genova, Alex; Maass, Alejandro; Davidson, William S; Yáñez, José M

2015-10-24

Pisciricketssia salmonis is the causal agent of Salmon Rickettsial Syndrome (SRS), which affects salmon species and causes severe economic losses. Selective breeding for disease resistance represents one approach for controlling SRS in farmed Atlantic salmon. Knowledge concerning the architecture of the resistance trait is needed before deciding on the most appropriate approach to enhance artificial selection for P. salmonis resistance in Atlantic salmon. The purpose of the study was to dissect the genetic variation in the resistance to this pathogen in Atlantic salmon. 2,601 Atlantic salmon smolts were experimentally challenged against P. salmonis by means of intra-peritoneal injection. These smolts were the progeny of 40 sires and 118 dams from a Chilean breeding population. Mortalities were recorded daily and the experiment ended at day 40 post-inoculation. Fish were genotyped using a 50K Affymetrix® Axiom® myDesignTM Single Nucleotide Polymorphism (SNP) Genotyping Array. A Genome Wide Association Analysis was performed on data from the challenged fish. Linear regression and logistic regression models were tested. Genome Wide Association Analysis indicated that resistance to P. salmonis is a moderately polygenic trait. There were five SNPs in chromosomes Ssa01 and Ssa17 significantly associated with the traits analysed. The proportion of the phenotypic variance explained by each marker is small, ranging from 0.007 to 0.045. Candidate genes including interleukin receptors and fucosyltransferase have been found to be physically linked with these genetic markers and may play an important role in the differential immune response against this pathogen. Due to the small amount of variance explained by each significant marker we conclude that genetic resistance to this pathogen can be more efficiently improved with the implementation of genetic evaluations incorporating genotype information from a dense SNP array.

The mutagenesis of a type IV secretion system locus of Piscirickettsia salmonis leads to the attenuation of the pathogen in Atlantic salmon, Salmo salar.

PubMed

Mancilla, M; Saavedra, J; Grandón, M; Tapia, E; Navas, E; Grothusen, H; Bustos, P

2018-04-01

Piscirickettsiosis is a threatening infectious disease for the salmon industry, due to it being responsible for significant economic losses. The control of outbreaks also poses considerable environmental challenges. Despite Piscirickettsia salmonis having been discovered as the aetiological agent of the disease more than 25 years ago, its pathogenicity remains poorly understood. Among virulence factors identified so far, type four secretion systems (T4SS) seem to play a key role during the infection caused by the bacterium. We report here the genetic manipulation of P. salmonis by means of the transference of plasmid DNA in mating assays. An insertion cassette was engineered for targeting the icmB gene, which encodes a putative T4SS-ATPase and is carried by one of the chromosomal T4SS clusters found within the genome of P. salmonis PM15972A1, a virulent representative of the EM-90-like strain. The molecular characterization of the resulting mutant strain demonstrated that the insertion interrupted the target gene. Further in vitro testing of the icmB mutant showed a dramatic drop in infectivity as tested in CHSE-214 cells, which is in agreement with its attenuated behaviour observed in vivo. Altogether, our results demonstrate that, similar to other facultative intracellular pathogens, P. salmonis' virulence relies on an intact T4SS. © 2017 The Authors. Journal of Fish Diseases Published by John Wiley & Sons Ltd.

Microcrustaceans (Branchipoda and Copepoda) of Wetland Impoundments on the Savannah River Site, Aiken, South Carolina

DOE Office of Scientific and Technical Information (OSTI.GOV)

DeBiase, Adrienne E; Taylor, Barbara E

2005-09-21

The United States Department of Energy’s Savannah River Site (SRS) in Aiken, Allendale, and Barnwell Counties, South Carolina, contains an abundance of freshwater wetlands and impoundments. Four large impoundments, as well as several small, abandoned farm and mill ponds, and about 400 Carolina bays and other small, isolated depression wetland ponds are located within the 893 km2 area of the SRS. Crustaceans of the orders Branchiopoda and Copepoda are nearly ubiquitous in these water bodies. Although small in size, these organisms are often very abundant. They consequently play an important trophic role in freshwater food webs supporting fish, larval salamanders,more » larval insects, and numerous other animals, aquatic and terrestrial. This report provides an introduction to the free-living microcrustaceans of lentic water bodies on the SRS and a comprehensive list of species known to occur there. Occurrence patterns are summarized from three extensive survey studies, supplemented with other published and unpublished records. In lieu of a key, we provide a guide to taxonomic resources and notes on undescribed species. Taxa covered include the orders Cladocera, Anostraca, Laevicaudata, and Spinicaudata of the Subclass Branchiopoda and the Superorders Calanoida and Cyclopoida of Subclass Copepoda. Microcrustaceans of the Superorder Harpacticoida of the Subclass Copepoda and Subclass Ostracoda are also often present in lentic water bodies. They are excluded from this report because they have not received much study at the species level on the SRS.« less

An isolate of Piscirickettsia salmonis from white seabass is fully virulent for coho salmon

USGS Publications Warehouse

House, M.L.; Hedrick, R.P.; Winton, J.R.; Fryer, J.L.

2006-01-01

The virulence of the WSB-98 isolate of Piscirickettsia salmonis from white seabass Atractoscion nobilis was compared with that of the American Type Culture Collection type strain LF-89, which was originally isolated from coho salmon Oncorhynchus kisutch in Chile. In controlled laboratory challenges of juvenile coho salmon, the isolate from white seabass exhibited virulence that was equal to or greater than that of LF-89. The cumulative percent mortality (CPM) was similar between groups of coho salmon receiving an intraperitoneal injection of WSB-98 at 104.5 tissue culture infectious dose with 50% endpoint (TCID50)/fish (CPM = 98%) or an injection of LF-89 at 104.8 TCID50/fish (CPM = 95%). The mean day to death of 9.3 d for WSB-98 and 18.6 d for LF-89, however, differed significantly (P < 0.0001) between the two isolates. The virulence of an isolate of P. salmonis from white seabass for a salmonid species is consistent with the hypothesis that nonsalmonids can serve as natural marine hosts for the bacterium and potential sources for infection of salmonids. ?? Copyright by the American Fisheries Society 2006.

Nutritional Immunity Triggers the Modulation of Iron Metabolism Genes in the Sub-Antarctic Notothenioid Eleginops maclovinus in Response to Piscirickettsia salmonis

PubMed Central

Martínez, Danixa; Oyarzún, Ricardo; Pontigo, Juan Pablo; Romero, Alex; Yáñez, Alejandro J.; Vargas-Chacoff, Luis

2017-01-01

Iron deprivation is a nutritional immunity mechanism through which fish can limit the amount of iron available to invading bacteria. The aim of this study was to evaluate the modulation of iron metabolism genes in the liver and brain of sub-Antarctic notothenioid Eleginops maclovinus challenged with Piscirickettsia salmonis. The specimens were inoculated with two P. salmonis strains: LF-89 (ATCC® VR-1361™) and Austral-005 (antibiotic resistant). Hepatic and brain samples were collected at intervals over a period of 35 days. Gene expression (by RT-qPCR) of proteins involved in iron storage, transport, and binding were statistically modulated in infected fish when compared with control counterparts. Specifically, the expression profiles of the transferrin and hemopexin genes in the liver, as well as the expression profiles of ferritin-M, ferritin-L, and transferrin in the brain, were similar for both experimental groups. Nevertheless, the remaining genes such as ferritin-H, ceruloplasmin, hepcidin, and haptoglobin presented tissue-specific expression profiles that varied in relation to the injected bacterial strain and sampling time-point. These results suggest that nutritional immunity could be an important immune defense mechanism for E. maclovinus against P. salmonis injection. This study provides relevant information for understanding iron metabolism of a sub-Antarctic notothenioid fish. PMID:28974951

Molecular cloning of Salmo salar Toll-like receptors (TLR1, TLR22, TLR5M and TLR5S) and expression analysis in SHK-1 cells during Piscirickettsia salmonis infection.

PubMed

Salazar, C; Haussmann, D; Kausel, G; Figueroa, J

2016-02-01

In fish, the innate immune system is the primary response against infection. Toll-like receptors (TLRs) recognize pathogens through pathogen-associated molecular patterns (PAMPs), and some target molecules of TLRs are homologous between fish and mammals. Piscirickettsia salmonis is one of the main pathogens affecting the salmon industry in Chile. Better knowledge of mechanisms underlying its invasive capacity and recognition of target cells is crucial for vaccine development. Therefore, Salmo salar L. TLR1, TLR22, membrane TLR5M and soluble TLR5S sequences were cloned, and expression kinetics were analysed by RT-qPCR in salmon head kidney cells (SHK-1) infected with three different P. salmonis preparations: alive, formaldehyde treated, extract. Clearly, all analysed TLRs were expressed and transcription level changes were revealed at 2 hpi, 12 or 16 hpi and 24 hpi depending on P. salmonis infection scheme. Increased IL1-beta expression confirmed TLR pathway response. Furthermore, significant expression modulations of several members of the TLR pathway in this in vitro model suggest that P. salmonis extract rather than formaldehyde-inactivated bacteria might strengthen the salmon immune system. © 2015 John Wiley & Sons Ltd.

Differences in Lepeophtheirus salmonis abundance levels on Atlantic salmon farms in the Broughton Archipelago, British Columbia, Canada.

PubMed

Saksida, S; Karreman, G A; Constantine, J; Donald, A

2007-06-01

Sea lice data collected from Atlantic salmon farms in the Broughton Archipelago between 2003 and 2005 were examined for inter-regional differences in mobile Lepeophtheirus salmonis (Krøyer) abundance using the generalized linear model procedure. Factors such as age of the salmon populations, location of farms and time of year had a significant effect on the abundance of the mobile stages of L. salmonis whereas water temperature and salinity did not. Separate evaluation of SLICE treatment data found no significant difference in treatment frequency among the areas but did show that there were significantly lower numbers of farm treatments during the summer months when compared with other seasons. The role of environment and wild fish in influencing sea lice abundance on the farmed salmon is discussed. The findings suggest that effective management programmes for sea lice should not only be based on geographical location but should take into account other factors which could influence lice abundance levels.

Genetic dissection of MHC-associated susceptibility to Lepeophtheirus salmonis in Atlantic salmon

PubMed Central

Gharbi, Karim; Glover, Kevin A; Stone, Louise C; MacDonald, Elizabeth S; Matthews, Louise; Grimholt, Unni; Stear, Michael J

2009-01-01

Background Genetic variation has been shown to play a significant role in determining susceptibility to the salmon louse, Lepeophtheirus salmonis. However, the mechanisms involved in differential response to infection remain poorly understood. Recent findings in Atlantic salmon (Salmo salar) have provided evidence for a potential link between marker variation at the major histocompatibility complex (MHC) and differences in lice abundance among infected siblings, suggesting that MHC genes can modulate susceptibility to the parasite. In this study, we used quantitative trait locus (QTL) analysis to test the effect of genomic regions linked to MHC class I and II on linkage groups (LG) 15 and 6, respectively. Results Significant QTL effects were detected on both LG 6 and LG 15 in sire-based analysis but the QTL regions remained unresolved due to a lack of recombination between markers. In dam-based analysis, a significant QTL was identified on LG 6, which accounted for 12.9% of within-family variance in lice abundance. However, the QTL was located at the opposite end of DAA, with no significant overlap with the MHC class II region. Interestingly, QTL modelling also revealed evidence of sex-linked differences in lice abundance, indicating that males and females may have different susceptibility to infection. Conclusion Overall, QTL analysis provided relatively weak support for a proximal effect of classical MHC regions on lice abundance, which can partly be explained by linkage to other genes controlling susceptibility to L. salmonis on the same chromosome. PMID:19397823

Effectiveness of emamectin benzoate for treatment of Lepeophtheirus salmonis on farmed Atlantic salmon Salmo salar in the Bay of Fundy, Canada.

PubMed

Jones, Patti G; Hammell, K Larry; Dohoo, Ian R; Revie, Crawford W

2012-12-03

Emamectin benzoate (an avermectin chemotherapeutant administered to fish as an in-feed treatment) has been used to treat infestations of sea lice Lepeophtheirus salmonis on farmed Atlantic salmon Salmo salar in the Bay of Fundy, New Brunswick, Canada, since 1999. This retrospective study examined the effectiveness of 114 emamectin benzoate treatment episodes from 2004 to 2008 across 54 farms. Study objectives were to establish whether changes in the effectiveness of emamectin benzoate were present for this period, examine factors associated with treatment outcome, and determine variables that influenced differences in L. salmonis abundance after treatment. The analysis was carried out in 2 parts: first, trends in treatment effectiveness and L. salmonis abundance were explored, and second, statistical modelling (linear and logistic regression) was used to examine the effects of multiple variables on post-treatment abundance and treatment outcome. Post-treatment sea lice abundance increased in the later years examined. Mean abundance differed between locations in the Bay of Fundy, and higher numbers were found at farms closer to the mainland and lower levels were found in the areas around Grand Manan Island. Treatment effectiveness varied by geographical region and decreased over time. There was an increased risk for unsuccessful treatments in 2008, and treatments applied during autumn months were more likely to be ineffective than those applied during summer months.

Genome Sequence of Streptococcus phocae subsp. salmonis Strain C-4T, Isolated from Atlantic Salmon (Salmo salar)

PubMed Central

Suarez, Rudy; Lazo, Eduardo; Bravo, Diego; Llegues, Katerina O.; Romalde, Jesús L.; Godoy, Marcos G.

2014-01-01

Streptococcus phocae subsp. salmonis is a fish pathogen that has an important impact on the Chilean salmon industry. Here, we report the genome sequence of the type strain C-4T isolated from Atlantic salmon (Salmo salar), showing a number of interesting features and genes related to its possible virulence factors. PMID:25502668

Immunological response of the Sub-Antarctic Notothenioid fish Eleginops maclovinus injected with two strains of Piscirickettsia salmonis.

PubMed

Martínez, D; Díaz-Ibarrola, D; Vargas-Lagos, C; Oyarzún, R; Pontigo, J P; Muñoz, J L P; Yáñez, A J; Vargas-Chacoff, L

2018-04-01

Eleginops maclovinus is an endemic fish to Chile that lives in proximity to salmonid culture centers, feeding off of uneaten pellet and salmonid feces. Occurring in the natural environment, this interaction between native and farmed fish could result in the horizontal transmission of pathogens affecting the aquaculture industry. The aim of this study was to evaluate the innate and adaptive immune responses of E. maclovinus challenged with P. salmonis. Treatment injections (in duplicate) were as follows: control (100 μL of culture medium), wild type LF-89 strain (100 μL, 1 × 10 8 live bacteria), and antibiotic resistant strain Austral-005 (100 μL, 1 × 10 8 live bacteria). The fish were sampled at various time-points during the 35-day experimental period. The gene expression of TLRs (1, 5, and 8), NLRCs (3 and 5), C3, IL-1β, MHCII, and IgMs were significantly modulated during the experimental period in both the spleen and gut (excepting TLR1 and TLR8 spleen expressions), with tissue-specific expression profiles and punctual differences between the injected strains. Anti-P. salmonis antibodies increased in E. maclovinus serum from day 14-28 for the LF-89 strain and from day 14-35 for the Austral-005 strain. These results suggest temporal activation of the innate and adaptive immune responses in E. maclovinus tissues when injected by distinct P. salmonis strains. The Austral-005 strain did not always cause the greatest increases/decreases in the number of transcripts, so the magnitude of the observed immune response (mRNA) may not be related to antibiotic resistance. This is the first immunological study to relate a pathogen widely studied in salmonids with a native fish. Copyright © 2018 Elsevier Ltd. All rights reserved.

Microcrustaceans (Branchiopoda and Copepoda) of Wetland Ponds and Impoundments on the Savannah River Site, Aiken, South Carolina

DOE Office of Scientific and Technical Information (OSTI.GOV)

Adrienne E. DeBiase; Barbara E. Taylor

2005-09-21

The United States Department of Energy's Savannah River Site (SRS) in Aiken, Allendale, and Barnwell Counties, South Carolina, contains an abundance of freshwater wetlands and impoundments. Four large impoundments, as well as several small, abandoned farm and mill ponds, and about 400 Carolina bays and other small, isolated depression wetland ponds are located within the 893 km2 area of the SRS. Crustaceans of the orders Branchiopoda and Copepoda are nearly ubiquitous in these water bodies. Although small in size, these organisms are often very abundant. They consequently play an important trophic role in freshwater food webs supporting fish, larval salamanders,more » larval insects, and numerous other animals, aquatic and terrestrial. This report provides an introduction to the free-living microcrustaceans of lentic water bodies on the SRS and a comprehensive list of species known to occur there. Occurrence patterns are summarized from three extensive survey studies, supplemented with other published and unpublished records. In lieu of a key, we provide a guide to taxonomic resources and notes on undescribed species. Taxa covered include the orders Cladocera, Anostraca, Laevicaudata, and Spinicaudata of the Subclass Branchiopoda and the Superorders Calanoida and Cyclopoida of Subclass Copepoda. Microcrustaceans of the Superorder Harpacticoida of the Subclass Copepoda and Subclass Ostracoda are also often present in lentic water bodies. They are excluded from this report because they have not received much study at the species level on the SRS.« less

Electrochemical detection of Piscirickettsia salmonis genomic DNA from salmon samples using solid-phase recombinase polymerase amplification.

PubMed

Del Río, Jonathan Sabaté; Svobodova, Marketa; Bustos, Paulina; Conejeros, Pablo; O'Sullivan, Ciara K

2016-12-01

Electrochemical detection of solid-phase isothermal recombinase polymerase amplification (RPA) of Piscirickettsia salmonis in salmon genomic DNA is reported. The electrochemical biosensor was constructed by surface functionalization of gold electrodes with a thiolated forward primer specific to the genomic region of interest. Solid-phase RPA and primer elongation were achieved in the presence of the specific target sequence and biotinylated reverse primers. The formation of the subsequent surface-tethered duplex amplicons was electrochemically monitored via addition of streptavidin-linked HRP upon completion of solid-phase RPA. Successful quantitative amplification and detection were achieved in less than 1 h at 37 °C, calibrating with PCR-amplified genomic DNA standards and achieving a limit of detection of 5 · 10 -8  μg ml -1 (3 · 10 3 copies in 10 μl). The presented system was applied to the analysis of eight real salmon samples, and the method was also compared to qPCR analysis, observing an excellent degree of correlation. Graphical abstract Schematic of use of electrochemical RPA for detection of Psiricketessia salmonis in salmon liver.

Multivariate evaluation of the effectiveness of treatment efficacy of cypermethrin against sea lice (Lepeophtheirus salmonis) in Atlantic salmon (Salmo salar)

PubMed Central

2013-01-01

Background The sea louse Lepeophtheirus salmonis is the most important ectoparasite of farmed Atlantic salmon (Salmo salar) in Norwegian aquaculture. Control of sea lice is primarily dependent on the use of delousing chemotherapeutants, which are both expensive and toxic to other wildlife. The method most commonly used for monitoring treatment effectiveness relies on measuring the percentage reduction in the mobile stages of Lepeophtheirus salmonis only. However, this does not account for changes in the other sea lice stages and may result in misleading or incomplete interpretation regarding the effectiveness of treatment. With the aim of improving the evaluation of delousing treatments, we explored multivariate analyses of bath treatments using the topical pyrethroid, cypermethrin, in salmon pens at five Norwegian production sites. Results Conventional univariate analysis indicated reductions of over 90% in mobile stages at all sites. In contrast, multivariate analyses indicated differing treatment effectiveness between sites (p-value < 0.01) based on changes in the proportion and abundance of the chalimus and PAAM (pre-adult and adult males) stages. Low water temperatures and shortened intervals between sampling after treatment may account for the differences in the composition of chalimus and PAAM stage groups following treatment. Using multivariate analysis, such factors could be separated from those which were attributable to inadequate treatment or chemotherapeutant failure. Conclusions Multivariate analyses for evaluation of treatment effectiveness against multiple life cycle stages of L. salmonis yield additional information beyond that derivable from univariate methods. This can aid in the identification of causes of apparent treatment failure in salmon aquaculture. PMID:24354936

Genome Sequence of Streptococcus phocae subsp. salmonis Strain C-4T, Isolated from Atlantic Salmon (Salmo salar).

PubMed

Avendaño-Herrera, Ruben; Suarez, Rudy; Lazo, Eduardo; Bravo, Diego; Llegues, Katerina O; Romalde, Jesús L; Godoy, Marcos G

2014-12-11

Streptococcus phocae subsp. salmonis is a fish pathogen that has an important impact on the Chilean salmon industry. Here, we report the genome sequence of the type strain C-4(T) isolated from Atlantic salmon (Salmo salar), showing a number of interesting features and genes related to its possible virulence factors. Copyright © 2014 Avendaño-Herrera et al.

Immunostimulation of Salmo salar L., and its effect on Lepeophtheirus salmonis (Krøyer) P-glycoprotein mRNA expression following subsequent emamectin benzoate exposure.

PubMed

Igboeli, O O; Purcell, S L; Wotton, H; Poley, J; Burka, J F; Fast, M D

2013-03-01

Control of sea lice, Lepeophtheirus salmonis, on farmed Atlantic salmon, Salmo salar, relies heavily on chemotherapeutants. However, reduced efficacy of many treatments and need for integrated sea lice management plans require innovative strategies. Resistance to emamectin benzoate (EMB), a major sea lice parasiticide, has been linked with P-glycoprotein (P-gp) expression. We hypothesized that host immunostimulation would complement EMB treatment outcome. Lepeophtheirus salmonis-infected Atlantic salmon were fed immunostimulatory or control feeds. Sea lice were collected for 24-h EMB bioassays 1 and 2 weeks prior to commencement of EMB treatment of the fish. Two weeks after cessation of immunostimulant-treated feed, EMB was administered at 150 μg kg(-1) fish biomass for 7 days. The bioassay revealed stage, gender and immunostimulant-related differences in EMB EC(50) . Sea lice attached to salmon with a history of immunostimulation exhibited significantly greater survival than those on control feeds, despite similar levels of EMB in host tissues. Lepeophtheirus salmonis from salmon with a history of immunostimulation also exhibited higher P-gp mRNA expression as well as greater survivability compared to controls. Administration of immunostimulants prior to EMB treatment caused increased expression of P-gp mRNA which could have consequently caused decreased efficacy of the parasiticide. © 2013 Blackwell Publishing Ltd.

Life history and virulence are linked in the ectoparasitic salmon louse Lepeophtheirus salmonis.

PubMed

Mennerat, A; Hamre, L; Ebert, D; Nilsen, F; Dávidová, M; Skorping, A

2012-05-01

Models of virulence evolution for horizontally transmitted parasites often assume that transmission rate (the probability that an infected host infects a susceptible host) and virulence (the increase in host mortality due to infection) are positively correlated, because higher rates of production of propagules may cause more damages to the host. However, empirical support for this assumption is scant and limited to microparasites. To fill this gap, we explored the relationships between parasite life history and virulence in the salmon louse, Lepeophtheirus salmonis, a horizontally transmitted copepod ectoparasite on Atlantic salmon Salmo salar. In the laboratory, we infected juvenile salmon hosts with equal doses of infective L. salmonis larvae and monitored parasite age at first reproduction, parasite fecundity, area of damage caused on the skin of the host, and host weight and length gain. We found that earlier onset of parasite reproduction was associated with higher parasite fecundity. Moreover, higher parasite fecundity (a proxy for transmission rate, as infection probability increases with higher numbers of parasite larvae released to the water) was associated with lower host weight gain (correlated with lower survival in juvenile salmon), supporting the presence of a virulence-transmission trade-off. Our results are relevant in the context of increasing intensive farming, where frequent anti-parasite drug use and increased host density may have selected for faster production of parasite transmission stages, via earlier reproduction and increased early fecundity. Our study highlights that salmon lice, therefore, are a good model for studying how human activity may affect the evolution of parasite virulence. © 2012 The Authors. Journal of Evolutionary Biology © 2012 European Society For Evolutionary Biology.

How sea lice from salmon farms may cause wild salmonid declines in Europe and North America and be a threat to fishes elsewhere

PubMed Central

Costello, Mark J.

2009-01-01

Fishes farmed in sea pens may become infested by parasites from wild fishes and in turn become point sources for parasites. Sea lice, copepods of the family Caligidae, are the best-studied example of this risk. Sea lice are the most significant parasitic pathogen in salmon farming in Europe and the Americas, are estimated to cost the world industry €300 million a year and may also be pathogenic to wild fishes under natural conditions. Epizootics, characteristically dominated by juvenile (copepodite and chalimus) stages, have repeatedly occurred on juvenile wild salmonids in areas where farms have sea lice infestations, but have not been recorded elsewhere. This paper synthesizes the literature, including modelling studies, to provide an understanding of how one species, the salmon louse, Lepeophtheirus salmonis, can infest wild salmonids from farm sources. Three-dimensional hydrographic models predicted the distribution of the planktonic salmon lice larvae best when they accounted for wind-driven surface currents and larval behaviour. Caligus species can also cause problems on farms and transfer from farms to wild fishes, and this genus is cosmopolitan. Sea lice thus threaten finfish farming worldwide, but with the possible exception of L. salmonis, their host relationships and transmission adaptations are unknown. The increasing evidence that lice from farms can be a significant cause of mortality on nearby wild fish populations provides an additional challenge to controlling lice on the farms and also raises conservation, economic and political issues about how to balance aquaculture and fisheries resource management. PMID:19586950

An evaluation of potential reference genes for stability of expression in two salmonid cell lines after infection with either Piscirickettsia salmonis or IPNV

PubMed Central

2010-01-01

Background Due to the limited number of species specific antibodies against fish proteins, differential gene expression analyses are vital for the study of host immune responses. Quantitative real-time reverse transcription PCR (qRT-PCR) is one of the most powerful tools for this purpose. Nevertheless, the accuracy of the method will depend on the careful selection of genes whose expression are stable and can be used as internal controls for a particular experimental setting. Findings The expression stability of five commonly used housekeeping genes [beta-actin (ACTB), elongation factor 1-alpha (EF1A), ubiquitin (UBQ), glyceraldehyd-3-phosphate dehydrogenase (GAPDH) and tubulin alpha (TUBA)] were monitored in salmonid cell lines CHSE-214 and RTS11 after infection with two of the most fastidious fish pathogens, the facultative bacterium Piscirickettsia salmonis and the aquabirnavirus IPNV (Infectious Pancreatic Necrosis Virus). After geNorm analysis, UBQ and EF1A appeared as the most stable, although EF1A was slightly upregulated at late stages of P. salmonis infection in RTS11. ACTB instead, showed a good performance in each case, being always considered within the three most stable genes of the panel. In contrast, infection-dependent differential regulation of GAPDH and TUBA was also demonstrated. Conclusion Based on the data presented here with the cell culture models CHSE-214 and RTS11, we suggest the initial choice of UBQ, ACTB and EF1A as reference genes in qRT-PCR assays for studying the effect of P. salmonis and IPNV on the host immune response. PMID:20398263

The complete mitochondrial genome of Arctic Calanus hyperboreus (Copepoda, Calanoida) reveals characteristic patterns in calanoid mitochondrial genome.

PubMed

Kim, Sanghee; Lim, Byung-Jin; Min, Gi-Sik; Choi, Han-Gu

2013-05-10

Copepoda is the most diverse and abundant group of crustaceans, but its phylogenetic relationships are ambiguous. Mitochondrial (mt) genomes are useful for studying evolutionary history, but only six complete Copepoda mt genomes have been made available and these have extremely rearranged genome structures. This study determined the mt genome of Calanus hyperboreus, making it the first reported Arctic copepod mt genome and the first complete mt genome of a calanoid copepod. The mt genome of C. hyperboreus is 17,910 bp in length and it contains the entire set of 37 mt genes, including 13 protein-coding genes, 2 rRNAs, and 22 tRNAs. It has a very unusual gene structure, including the longest control region reported for a crustacean, a large tRNA gene cluster, and reversed GC skews in 11 out of 13 protein-coding genes (84.6%). Despite the unusual features, comparing this genome to published copepod genomes revealed retained pan-crustacean features, as well as a conserved calanoid-specific pattern. Our data provide a foundation for exploring the calanoid pattern and the mechanisms of mt gene rearrangement in the evolutionary history of the copepod mt genome. Copyright © 2012 Elsevier B.V. All rights reserved.

Ca. Branchiomonas cysticola, Ca. Piscichlamydia salmonis and Salmon Gill Pox Virus transmit horizontally in Atlantic salmon held in fresh water.

PubMed

Wiik-Nielsen, J; Gjessing, M; Solheim, H T; Litlabø, A; Gjevre, A-G; Kristoffersen, A B; Powell, M D; Colquhoun, D J

2017-10-01

Elucidation of the role of infectious agents putatively involved in gill disease is commonly hampered by the lack of culture systems for these organisms. In this study, a farmed population of Atlantic salmon pre-smolts, displaying proliferative gill disease with associated Candidatus Branchiomonas cysticola, Ca. Piscichlamydia salmonis and Atlantic salmon gill pox virus (SGPV) infections, was identified. A subpopulation of the diseased fish was used as a source of waterborne infection towards a population of naïve Atlantic salmon pre-smolts. Ca. B. cysticola infection became established in exposed naïve fish at high prevalence within the first month of exposure and the bacterial load increased over the study period. Ca. P. salmonis and SGPV infections were identified only at low prevalence in exposed fish during the trial. Although clinically healthy, at termination of the trial the exposed, naïve fish displayed histologically visible pathological changes typified by epithelial hyperplasia and subepithelial inflammation with associated bacterial inclusions, confirmed by fluorescent in situ hybridization to contain Ca. B. cysticola. The results strongly suggest that Ca. B. cysticola infections transmit directly from fish to fish and that the bacterium is directly associated with the pathological changes observed in the exposed, previously naïve fish. © 2017 John Wiley & Sons Ltd.

A model for studying isolation mechanisms in parasite populations: the genus Lepeophtheirus (Copepoda, Caligidae).

PubMed

De Meeus, T; Renaud, F; Gabrion, C

1990-05-01

In the Mediterranean, the parasitic copepod Lepeophtheirus thompsoni Baird, 1850 specifically infests turbot (Psetta maxima L., 1758), whereas L. europaensis Zeddam, Berrebi, Renaud, Raibaut, and Gabrion, 1988 infests brill (Scophthalmus rhombus L., 1758) and flounder (Platichthys flesus L., 1758). Experimental infestation of turbot by copepods from each of the three fish species showed an absence of any physiological incompatibility preventing natural development of the two parasite species, at least on one host species, i.e., the turbot. Moreover, interspecific hybrids were obtained experimentally, which implies that 1) there is no strict genetic barrier between the two species and 2) the natural prezygotic isolation results from a choice of the most favorable habitat. We discuss the origin and possible consequences of the presence, in the Mediterranean, of L. europaensis on brill and flounder, two hosts separated by their taxonomic status and ecobiology.

Salmon lice (Lepeophtheirus salmonis) showing varying emamectin benzoate susceptibilities differ in neuronal acetylcholine receptor and GABA-gated chloride channel mRNA expression.

PubMed

Carmichael, Stephen N; Bron, James E; Taggart, John B; Ireland, Jacqueline H; Bekaert, Michaël; Burgess, Stewart Tg; Skuce, Philip J; Nisbet, Alasdair J; Gharbi, Karim; Sturm, Armin

2013-06-18

Caligid copepods, also called sea lice, are fish ectoparasites, some species of which cause significant problems in the mariculture of salmon, where the annual cost of infection is in excess of €300 million globally. At present, caligid control on farms is mainly achieved using medicinal treatments. However, the continued use of a restricted number of medicine actives potentially favours the development of drug resistance. Here, we report transcriptional changes in a laboratory strain of the caligid Lepeophtheirus salmonis (Krøyer, 1837) that is moderately (~7-fold) resistant to the avermectin compound emamectin benzoate (EMB), a component of the anti-salmon louse agent SLICE® (Merck Animal Health). Suppression subtractive hybridisation (SSH) was used to enrich transcripts differentially expressed between EMB-resistant (PT) and drug-susceptible (S) laboratory strains of L. salmonis. SSH libraries were subjected to 454 sequencing. Further L. salmonis transcript sequences were available as expressed sequence tags (EST) from GenBank. Contiguous sequences were generated from both SSH and EST sequences and annotated. Transcriptional responses in PT and S salmon lice were investigated using custom 15 K oligonucleotide microarrays designed using the above sequence resources. In the absence of EMB exposure, 359 targets differed in transcript abundance between the two strains, these genes being enriched for functions such as calcium ion binding, chitin metabolism and muscle structure. γ-aminobutyric acid (GABA)-gated chloride channel (GABA-Cl) and neuronal acetylcholine receptor (nAChR) subunits showed significantly lower transcript levels in PT lice compared to S lice. Using RT-qPCR, the decrease in mRNA levels was estimated at ~1.4-fold for GABA-Cl and ~2.8-fold for nAChR. Salmon lice from the PT strain showed few transcriptional responses following acute exposure (1 or 3 h) to 200 μg L-1 of EMB, a drug concentration tolerated by PT lice, but toxic for S lice

On the occurrence of caligids (Copepoda: Siphonostomatoida) in the marine plankton: a review and checklist.

PubMed

Maran, Balu Alagar Venmathi; Suárez-Morales, Eduardo; Ohtsuka, Susumu; Soh, Ho Young; Hwang, Ui Wook

2016-10-11

Members of the copepod genus Caligus Müller, 1785 (Siphonostomatoida: Caligidae) are commonly referred to as sea lice. Virtually all of the more than 450 species utilize marine fishes as hosts, however, an increasing number of records from marine plankton samples shows that at least some species reside in the water column during their adult phase. Members of three different genera, Caligus, Lepeophtheirus von Nordmann, 1832, and Metacaligus Thomsen, 1949 have been reported from plankton samples off eastern Asia and in the north-western Atlantic. Thirteen species have so far been consistently reported from the plankton only with no information on their hosts. Here we review the various hypotheses previously proposed to explain the presence of caligids in the water column, i.e. accidental occurrence, behavioral detachment from the host during mate location, and host-switching. The discovery of adults of two species of Caligus with no other developmental stages on their teleost hosts, suggests an ontogenetic host-switching after the final molt since both species also occurred in plankton samples. A checklist of all caligid records from the marine plankton, including known host data, is presented.

Ionotropic receptors signal host recognition in the salmon louse (Lepeophtheirus salmonis, Copepoda).

PubMed

Komisarczuk, Anna Z; Grotmol, Sindre; Nilsen, Frank

2017-01-01

A remarkable feature of many parasites is a high degree of host specificity but the mechanisms behind are poorly understood. A major challenge for parasites is to identify and infect a suitable host. Many species show a high degree of host specificity, being able to survive only on one or a few related host species. To facilitate transmission, parasite's behavior and reproduction has been fine tuned to maximize the likelihood of infection of a suitable host. For some species chemical cues that trigger or attract the parasite in question have been identified but how metazoan parasites themselves receive these signals remains unknown. In the present study we show that ionotropic receptors (IRs) in the salmon louse are likely responsible for identification of a specific host. By using RNAi to knock down the expression level of different co-receptors, a significant change of infectivity and settlement of lice larvae was achieved on Atlantic salmon. More remarkably, knock down of the IRs changed the host specificity of the salmon louse and lice larvae settled at a significant rate on host that the wild type lice rejected within minutes. To our knowledge, this has never before been demonstrated for any metazoan parasite. Our results show that the parasites are able to identify the host quickly upon settlement, settle and initiate the parasitic life style if they are on the right host. This novel discovery opens up for utilizing the host recognition system for future parasite control.

Ionotropic receptors signal host recognition in the salmon louse (Lepeophtheirus salmonis, Copepoda)

PubMed Central

Grotmol, Sindre; Nilsen, Frank

2017-01-01

A remarkable feature of many parasites is a high degree of host specificity but the mechanisms behind are poorly understood. A major challenge for parasites is to identify and infect a suitable host. Many species show a high degree of host specificity, being able to survive only on one or a few related host species. To facilitate transmission, parasite’s behavior and reproduction has been fine tuned to maximize the likelihood of infection of a suitable host. For some species chemical cues that trigger or attract the parasite in question have been identified but how metazoan parasites themselves receive these signals remains unknown. In the present study we show that ionotropic receptors (IRs) in the salmon louse are likely responsible for identification of a specific host. By using RNAi to knock down the expression level of different co-receptors, a significant change of infectivity and settlement of lice larvae was achieved on Atlantic salmon. More remarkably, knock down of the IRs changed the host specificity of the salmon louse and lice larvae settled at a significant rate on host that the wild type lice rejected within minutes. To our knowledge, this has never before been demonstrated for any metazoan parasite. Our results show that the parasites are able to identify the host quickly upon settlement, settle and initiate the parasitic life style if they are on the right host. This novel discovery opens up for utilizing the host recognition system for future parasite control. PMID:28582411

Relative virulence of three isolates of Piscirickettsia salmonis for coho salmon Oncorhynchus kisutch

USGS Publications Warehouse

House, M.L.; Bartholomew, J.L.; Winton, J.R.; Fryer, J.L.

1999-01-01

Piscirickettsia salmonis was first recognized as the cause of mortality among pen-reared coho salmon Oncorhynchus kisutch in Chile. Since the initial isolation of this intracellular Gram-negative bacterium in 1989, similar organisms have been described from several areas of the world, but the associated outbreaks were not reported to be as serious as those that occurred in Chile. To determine if this was due to differences in virulence among isolates of P. salmonis, we conducted an experiment comparing isolates from Chile, British Columbia, Canada, and Norway (LF-89, ATL-4-91 and NOR-92, respectively). For each of the isolates, 3 replicates of 30 coho salmon were injected intraperitoneally with each of 3 concentrations of the bacterium. Negative control fish were injected with MEM-10. Mortalities were collected daily for 41 d post-injection. Piscirickettsiosis was observed in fish injected with each of the 3 isolates, and for each isolate, cumulative mortality was directly related to the concentration of bacterial cells administered. The LF-89 isolate was the most virulent, with losses reaching 97% in the 3 replicates injected with 105.0 TCID50, 91% in the replicates injected with 104.0 TCID50, and 57% in the fish injected with 103.0 TCID50. The ATL-4-91 isolate caused losses of 92% in the 3 replicates injected with 105.0 TCID50, 76% in the fish injected with 104.0 TCID50, and 32% in those injected with 103.0 TCID50. The NOR-92 isolate was the least virulent, causing 41% mortality in the replicates injected with 104.6 TCID50. At 41 d post-injection, 6% of the fish injected with 103.6 TCID50 NOR-92 had died. Mortality was only 2% in the fish injected with 102.6 TCID50 NOR-92, which was the same as the negative control group. Because the group injected with the highest concentration (104.6 TCID50) of NOR-92 was still experiencing mortality at 41 d, it was held for an additional 46 d. At 87 d post-injection, the cumulative mortality in this group had reached 70

Salmon lice (Lepeophtheirus salmonis) showing varying emamectin benzoate susceptibilities differ in neuronal acetylcholine receptor and GABA-gated chloride channel mRNA expression

PubMed Central

2013-01-01

Background Caligid copepods, also called sea lice, are fish ectoparasites, some species of which cause significant problems in the mariculture of salmon, where the annual cost of infection is in excess of €300 million globally. At present, caligid control on farms is mainly achieved using medicinal treatments. However, the continued use of a restricted number of medicine actives potentially favours the development of drug resistance. Here, we report transcriptional changes in a laboratory strain of the caligid Lepeophtheirus salmonis (Krøyer, 1837) that is moderately (~7-fold) resistant to the avermectin compound emamectin benzoate (EMB), a component of the anti-salmon louse agent SLICE® (Merck Animal Health). Results Suppression subtractive hybridisation (SSH) was used to enrich transcripts differentially expressed between EMB-resistant (PT) and drug-susceptible (S) laboratory strains of L. salmonis. SSH libraries were subjected to 454 sequencing. Further L. salmonis transcript sequences were available as expressed sequence tags (EST) from GenBank. Contiguous sequences were generated from both SSH and EST sequences and annotated. Transcriptional responses in PT and S salmon lice were investigated using custom 15 K oligonucleotide microarrays designed using the above sequence resources. In the absence of EMB exposure, 359 targets differed in transcript abundance between the two strains, these genes being enriched for functions such as calcium ion binding, chitin metabolism and muscle structure. γ-aminobutyric acid (GABA)-gated chloride channel (GABA-Cl) and neuronal acetylcholine receptor (nAChR) subunits showed significantly lower transcript levels in PT lice compared to S lice. Using RT-qPCR, the decrease in mRNA levels was estimated at ~1.4-fold for GABA-Cl and ~2.8-fold for nAChR. Salmon lice from the PT strain showed few transcriptional responses following acute exposure (1 or 3 h) to 200 μg L-1 of EMB, a drug concentration tolerated by PT lice, but

Genomic predictions can accelerate selection for resistance against Piscirickettsia salmonis in Atlantic salmon (Salmo salar).

PubMed

Bangera, Rama; Correa, Katharina; Lhorente, Jean P; Figueroa, René; Yáñez, José M

2017-01-31

Salmon Rickettsial Syndrome (SRS) caused by Piscirickettsia salmonis is a major disease affecting the Chilean salmon industry. Genomic selection (GS) is a method wherein genome-wide markers and phenotype information of full-sibs are used to predict genomic EBV (GEBV) of selection candidates and is expected to have increased accuracy and response to selection over traditional pedigree based Best Linear Unbiased Prediction (PBLUP). Widely used GS methods such as genomic BLUP (GBLUP), SNPBLUP, Bayes C and Bayesian Lasso may perform differently with respect to accuracy of GEBV prediction. Our aim was to compare the accuracy, in terms of reliability of genome-enabled prediction, from different GS methods with PBLUP for resistance to SRS in an Atlantic salmon breeding program. Number of days to death (DAYS), binary survival status (STATUS) phenotypes, and 50 K SNP array genotypes were obtained from 2601 smolts challenged with P. salmonis. The reliability of different GS methods at different SNP densities with and without pedigree were compared to PBLUP using a five-fold cross validation scheme. Heritability estimated from GS methods was significantly higher than PBLUP. Pearson's correlation between predicted GEBV from PBLUP and GS models ranged from 0.79 to 0.91 and 0.79-0.95 for DAYS and STATUS, respectively. The relative increase in reliability from different GS methods for DAYS and STATUS with 50 K SNP ranged from 8 to 25% and 27-30%, respectively. All GS methods outperformed PBLUP at all marker densities. DAYS and STATUS showed superior reliability over PBLUP even at the lowest marker density of 3 K and 500 SNP, respectively. 20 K SNP showed close to maximal reliability for both traits with little improvement using higher densities. These results indicate that genomic predictions can accelerate genetic progress for SRS resistance in Atlantic salmon and implementation of this approach will contribute to the control of SRS in Chile. We recommend GBLUP for routine

Commercial trials using emamectin benzoate to control sea lice Lepeophtheirus salmonis infestations in Atlantic salmon Salmo salar.

PubMed

Stone, J; Sutherland, I H; Sommerville, C; Richards, R H; Varma, K J

2000-06-19

Two trials were conducted at commercial salmon farms to evaluate the efficacy of emamectin benzoate (Slice, 0.2% aquaculture pre-mix, Schering-Plough Animal Health) as a treatment for sea lice Lepeophtheirus salmonis (Krøyer) and Caligus elongatus Nordmann infestations in Atlantic salmon Salmo salar L. Trials were carried out in 15 m2 commercial sea pens, at temperatures of 5.5 to 7.5 degrees C and 10.8 to 13.8 degrees C. Each pen was stocked with 14,000 to 17,500 fish with mean weights of 0.44 to 0.74 and 1.33 to 1.83 kg. Fish were naturally infested with sea lice at the start of each trial. At Day -1, samples of 10 or 15 fish were taken from each pen to determine pre-treatment numbers of lice. Emamectin benzoate was administered in feed, to 4 replicate pens, at a dose of 50 micrograms kg-1 biomass d-1 for 7 consecutive days (Days 0 to 6). Sea lice were counted again, between Days 7 and 77, and comparisons made with untreated control fish. Despite adverse weather conditions, wide variations in fish weights and exposure to new infestations, treatment was effective against chalimus and motile stages of L. salmonis. In the autumn trial, efficacy at Day 27 was 89%, and lice numbers remained lower on treated fish than on control fish 64 d from the start of treatment. In the winter trial, reductions in lice numbers at low temperatures were slower but good efficacy was achieved by Day 35. Although control fish had to be treated with hydrogen peroxide at Day 21, fish treated only with emamectin benzoate on Days 0 to 6 still had 89% fewer lice than control fish at Day 35. There were very few C. elongatus present, but at the end of both trials numbers were lower on treated fish. No adverse effects were associated with treatment of fish with emamectin benzoate.

Novel insights into the response of Atlantic salmon (Salmo salar) to Piscirickettsia salmonis: Interplay of coding genes and lncRNAs during bacterial infection.

PubMed

Valenzuela-Miranda, Diego; Gallardo-Escárate, Cristian

2016-12-01

Despite the high prevalence and impact to Chilean salmon aquaculture of the intracellular bacterium Piscirickettsia salmonis, the molecular underpinnings of host-pathogen interactions remain unclear. Herein, the interplay of coding and non-coding transcripts has been proposed as a key mechanism involved in immune response. Therefore, the aim of this study was to evidence how coding and non-coding transcripts are modulated during the infection process of Atlantic salmon with P. salmonis. For this, RNA-seq was conducted in brain, spleen, and head kidney samples, revealing different transcriptional profiles according to bacterial load. Additionally, while most of the regulated genes annotated for diverse biological processes during infection, a common response associated with clathrin-mediated endocytosis and iron homeostasis was present in all tissues. Interestingly, while endocytosis-promoting factors and clathrin inductions were upregulated, endocytic receptors were mainly downregulated. Furthermore, the regulation of genes related to iron homeostasis suggested an intracellular accumulation of iron, a process in which heme biosynthesis/degradation pathways might play an important role. Regarding the non-coding response, 918 putative long non-coding RNAs were identified, where 425 were newly characterized for S. salar. Finally, co-localization and co-expression analyses revealed a strong correlation between the modulations of long non-coding RNAs and genes associated with endocytosis and iron homeostasis. These results represent the first comprehensive study of putative interplaying mechanisms of coding and non-coding RNAs during bacterial infection in salmonids. Copyright © 2016 Elsevier Ltd. All rights reserved.

Evidence for changes in the transcription levels of two putative P-glycoprotein genes in sea lice (Lepeophtheirus salmonis) in response to emamectin benzoate exposure.

PubMed

Tribble, Nicholas D; Burka, John F; Kibenge, Frederick S B

2007-05-01

Overexpression of P-glycoproteins (Pgps) is assumed to be a principal mechanism of resistance of nematodes and arthropods to macrocyclic lactones. Quantitative RT-PCR (Q-RT-PCR) was used to demonstrate changes in transcription levels of two putative P-glycoprotein genes, designated here as SL0525 and SL-Pgp1, in sea lice (Lepeophtheirus salmonis) following exposure to emamectin benzoate (EMB). Pre-adult L. salmonis were challenged in an EMB bioassay for 24h and gene expression was studied from lice surviving EMB concentrations of 0, 10, and 30ppb. Gene expression was measured using Q-RT-PCR with elongation factor 1 (eEF1alpha) as an internal reference gene. The results show that both target genes, SL0525 and SL-Pgp1, had significantly increased levels of expression with exposure to 10ppb EMB (p=0.11 and p=0.17, respectively) whereas the group exposed to 30ppb was on the verge of being significant (p=0.053) only in the expression of SL-Pgp1. Gene expression for SL0525 and SL-Pgp1 were increased over five-fold at 10ppb EMB. Therefore, the upregulation of these target genes may offer protection by increasing Pgp expression when lice are exposed to EMB. Our optimized Q-RT-PCR can be used to determine if over-expression of these genes could be the basis for development of resistance in sea lice and thus allow suitable alternative chemotherapeutic options to be assessed.

Leaf litter copepods from a cloud forest mountain top in Honduras (Copepoda: Cyclopidae, Canthocamptidae).

PubMed

Fiers, Frank; Jocque, Merlijn

2013-01-01

Five different species of Copepoda were extracted from a leaf litter sample collected on the top (at 2000 m a.s.l.) of a cloud forested mountain in El Cusuco National Park, Honduras. Three of them, one Cyclopidae and two Canthocamptidae are new to science, and are described herein. Olmeccyclops hondo sp. nov. is the second representative thus far known of this New World genus. Moraria catracha sp. nov. and Moraria cusuca sp. nov. are the first formally described members of the genus occurring in Central America. The concept of a "Moraria-group" is considered to be an artificial grouping and is limited here to the genera Moraria and Morariopsis only. The distributional range of this group is essentially Holarctic, with the mountainous regions in Honduras, and probably in west Nicaragua, as the southernmost limits in the New World.

High-throughput SNP discovery and transcriptome expression profiles from the salmon louse Caligus rogercresseyi (Copepoda: Caligidae).

PubMed

Nuñez-Acuña, Gustavo; Valenzuela-Muñoz, Valentina; Gallardo-Escárate, Cristian

2014-06-01

The salmon louse Caligus rogercresseyi is the dominant ectoparasite species affecting the salmon aquaculture industry in the Southern hemisphere, and it is currently the main cause for economic losses in Chilean aquaculture. However, despite the great concern over Caligus infestations, genomic information on this louse is still scarce, even while the need to develop high-resolution molecular markers is growing. This study provides the first deep transcriptome survey to identify thousands of SNP markers from C. rogercresseyi, with a total of 69,466 SNPs identified using the MiSeq platform (Illumina®), 30,605 (52%) of which were found in contigs successfully annotated against known protein databases. Furthermore, in silico gene expression profiles associated with SNP variants were evaluated, and the results evidenced a wide array of genes that were down- and upregulated throughout the developmental stages of C. rogercresseyi. Interestingly, putative KEGG pathways involved in resistance to antiparasitic agents were also identified, where ten pathways were associated with the nervous system and one was related to ABC transporters. Taken together, this information could be highly useful for investigating the molecular underpinnings involved in the susceptibility or resistance of salmon lice to chemical treatments. Copyright © 2014 Elsevier Inc. All rights reserved.

Comparative pathogenesis of piscirickettsiosis in Atlantic salmon (Salmo salar L.) post-smolt experimentally challenged with LF-89-like and EM-90-like Piscirickettsia salmonis isolates.

PubMed

Rozas-Serri, M; Ildefonso, R; Peña, A; Enríquez, R; Barrientos, S; Maldonado, L

2017-10-01

Piscirickettsiosis (SRS) is the most prevalent bacterial disease in Chilean salmon aquaculture and is responsible for high economic losses. The aim of this study was to comparatively characterize the pathogenesis of SRS in post-smolt Atlantic salmon during the early and late stages of infection with Piscirickettsia salmonis LF-89-like (PS-LF-89) and EM-90-like (PS-EM-90) using a cohabitation challenge. The pathogenesis of cohabitant fish infected with the two isolates was relatively different due to cohabitant fish infected with PS-EM-90 showing higher cumulative mortality and shorter time until death compared with PS-LF-89 fish. PS-LF-89 caused an SRS infection characterized by kidney and liver lesions, whereas PS-EM-90 caused systemic and haemorrhagic disease characterized by kidney, liver, heart, brain, skeletal muscle and intestine lesions. Decreased serum concentration of total proteins and albumin as well as increased serum ALT, AST and creatinine levels in fish infected with both isolates confirmed that changes in liver and kidney function occurred during infection. Tissue damage, expressed as an SRS histoscore, showed a strong positive correlation with the bacterial load expressed as abundance of P. salmonis 16S rRNA transcripts in the livers and kidneys of fish affected with either isolate, but the correlation was significantly higher in fish infected with PS-EM-90. The results contribute to improving the understanding of the bacteria-host interaction. © 2017 John Wiley & Sons Ltd.

Neuropeptide discovery in Eucyclops serrulatus (Crustacea, Copepoda): in silico prediction of the first peptidome for a member of the Cyclopoida.

PubMed

Christie, Andrew E

2015-01-15

Crustaceans of the subclass Copepoda are key components of essentially all aquatic ecosystems as they serve both as the primary consumers of phytoplankton and/or as major food sources for a wide variety of higher-level consumers. The dominant group of copepods in most freshwater ecosystems is the Cyclopoida; members of this order are routinely used as environmental indicators, and some predatory species are used for the biological control of disease-causing mosquitoes. Given their ecological and disease control importance, it is surprising that little is known about endocrine control in cyclopoids. Here, as part of an ongoing effort to identify and characterize the neurochemical signaling systems of members of the Copepoda, the extant transcriptome shotgun assembly for Eucyclops serrulatus, a member of the Cyclopoida, was mined for transcripts encoding putative peptide hormone-encoding transcripts. Via queries using known arthropod pre/preprohormone sequences, primarily ones from other copepod species, 36 E. serrulatus peptide-encoding transcripts were identified. The proteins deduced from these sequences allowed for the prediction of 160 unique mature neuropeptides, including the first copepod isoform of pigment dispersing hormone, as well as isoforms of adipokinetic hormone-corazonin-like peptide, allatostatin A, allatostatin B, allatostatin C, allatotropin, crustacean hyperglycemic hormone, diuretic hormone 31, DXXRLamide, FLRFamide, FXGGXamide, GSEFLamide, insulin-like peptide, intocin, leucokinin, myosuppressin, neuroparsin, neuropeptide F and tachykinin-related peptide. These peptides are currently the only ones known from any member of the Cyclopoida, and as such, provide a new resource for investigating peptidergic signaling in this important copepod order. Copyright © 2014 Elsevier Inc. All rights reserved.

Ichthyobodo salmonis sp. n. (Ichthyobodonidae, Kinetoplastida), an euryhaline ectoparasite infecting Atlantic salmon (Salmo salar L.)

PubMed Central

ISAKSEN, TROND E.; KARLSBAKK, EGIL; WATANABE, KUNINORI; NYLUND, ARE

2011-01-01

SUMMARY Phylogenetic analyses of SSU rDNA sequences have previously revealed the existence of 2 Ichthyobodo species able to infect Atlantic salmon (Salmo salar L.). Ichthyobodo necator sensu stricto (s.s.) is assumed to be a freshwater parasite, while a genetically distinct but undescribed species, Ichthyobodo sp. II sensu Todal et al. (2004) have been detected on Atlantic salmon in both fresh- and seawater. In the present study a morphological description of Ichthyobodo sp. II from the gills of salmon reared in fresh-, brackish- and seawater is presented, using both light- and electron microscopy. Comparative morphometry show that Ichthyobodo sp. II from both freshwater and seawater displays a different cell shape, and is significantly smaller than I. necator s.s. Also, ultrastructural characteristics distinguish these two species, notably differences in the attachment region and the presence of spine-like surface projections in Ichthyobodo sp. II. Based on both unique SSU rDNA sequences and morphological characteristics, we conclude that Ichthyobodo sp. II. represents a novel species for which we propose the name Ichthyobodo salmonis sp. n. PMID:21756424

The complete mitogenome of the whale shark parasitic copepod Pandarus rhincodonicus norman, Newbound & Knott (Crustacea; Siphonostomatoida; Pandaridae)--a new gene order for the copepoda.

PubMed

Austin, Christopher M; Tan, Mun Hua; Lee, Yin Peng; Croft, Laurence J; Meekan, Mark G; Pierce, Simon J; Gan, Han Ming

2016-01-01

The complete mitochondrial genome of the parasitic copepod Pandarus rhincodonicus was obtained from a partial genome scan using the HiSeq sequencing system. The Pandarus rhincodonicus mitogenome has 14,480 base pairs (62% A+T content) made up of 12 protein-coding genes, 2 ribosomal subunit genes, 22 transfer RNAs, and a putative 384 bp non-coding AT-rich region. This Pandarus mitogenome sequence is the first for the family Pandaridae, the second for the order Siphonostomatoida and the sixth for the Copepoda.

Effects of the vertically transmitted microsporidian Facilispora margolisi and the parasiticide emamectin benzoate on salmon lice (Lepeophtheirus salmonis).

PubMed

Poley, Jordan D; Sutherland, Ben J G; Fast, Mark D; Koop, Ben F; Jones, Simon R M

2017-08-17

Microsporidia are highly specialized, parasitic fungi that infect a wide range of eukaryotic hosts from all major taxa. Infections cause a variety of damaging effects on host physiology from increased stress to death. The microsporidian Facilispora margolisi infects the Pacific salmon louse (Lepeophtheirus salmonis oncorhynchi), an economically and ecologically important ectoparasitic copepod that can impact wild and cultured salmonids. Vertical transmission of F. margolisi was demonstrated by using PCR and in situ hybridization to identify and localize microsporidia in female L. salmonis and their offspring. Spores and developmental structures of F. margolisi were identified in 77% of F 1 generation copepods derived from infected females while offspring from uninfected females all tested negative for the microsporidia. The transcriptomic response of the salmon louse to F. margolisi was profiled at both the copepodid larval stage and the pre-adult stage using microarray technology. Infected copepodids differentially expressed 577 transcripts related to stress, ATP generation and structural components of muscle and cuticle. The infection also impacted the response of the copepodid to the parasiticide emamectin benzoate (EMB) at a low dose of 1.0 ppb for 24 h. A set of 48 transcripts putatively involved in feeding and host immunomodulation were up to 8-fold underexpressed in the F. margolisi infected copepodids treated with EMB compared with controls or either stressor alone. Additionally, these infected lice treated with EMB also overexpressed 101 transcripts involved in stress resistance and signalling compared to the other groups. In contrast, infected pre-adult lice did not display a stress response, suggesting a decrease in microsporidian virulence associated with lice maturity. Furthermore, copepodid infectivity and moulting was not affected by the microsporidian infection. This study demonstrated that F. margolisi is transmitted vertically between salmon

Increasing transcriptome response of serpins during the ontogenetic stages in the salmon louse Caligus rogercresseyi (Copepoda: Caligidae).

PubMed

Maldonado-Aguayo, W; Gallardo-Escárate, C

2014-06-01

Serine protease inhibitors, or serpins, target serine proteases, and are important regulators of intra- and extracellular proteolysis. For parasite survival, parasite-derived protease inhibitors have been suggested to play essential roles in evading the host's immune system and protecting against exogenous host proteases. The aim of this work was to identify serpins via high throughput transcriptome sequencing and elucidate their potential functions during the lifecycle of the salmon louse Caligus rogercresseyi. Eleven putative, partial serpin sequences in the C. rogercresseyi transcriptome were identified and denoted as Cr-serpins 1 to 11. Comparative analysis of the deduced serpin-like amino acid sequences revealed a highly conserved reactive center loop region. Interestingly, P1 residues suggest putative functions involved with the trypsin/subtilisin, elastase, or subtilisin inhibitors, which evidenced increasing gene expression profiles from the copepodid to adult stage in C. rogercresseyi. Concerning this, Cr-serpin 10 was mainly expressed in the copepodid stage, while Cr-serpins 3, 4, 5, and 11 were mostly expressed in chalimus and adult stages. These results suggest that serpins could be involved in evading the immune response of the host fish. The identification of these serpins furthers the understanding of the immune system in this important ectoparasite species. Copyright © 2014 Elsevier B.V. All rights reserved.

The reproductive effort of Lepeophtheirus pectoralis (Copepoda: Caligidae): insights into the egg production strategy of parasitic copepods.

PubMed

Frade, D G; Santos, M J; Cavaleiro, F I

2016-01-01

The reproductive effort of Lepeophtheirus pectoralis (Müller O. F., 1776), a caligid copepod, which is commonly found infecting the European flounder, Platichthys flesus (Linnaeus, 1758), is studied in detail for the first time. Seasonal variation in body dimensions and reproductive effort are analysed. Data for 120 ovigerous females, 30 from each season of the year, were considered in the analyses. Females were larger and produced a larger number of smaller eggs in winter, than during the summer. The relationship between egg number and egg size is similar to that recorded for other copepods exploiting fish hosts. Much of the recorded variation was also similar to that reported for a copepod parasitic on an invertebrate host, which suggests the possibility of a general trend in copepod reproduction. Overall, our results provide further support for the hypothesis that there is an alternation of summer and winter generations.

Comparative transcriptomics of Atlantic Salmo salar, chum Oncorhynchus keta and pink salmon O. gorbuscha during infections with salmon lice Lepeophtheirus salmonis.

PubMed

Sutherland, Ben J G; Koczka, Kim W; Yasuike, Motoshige; Jantzen, Stuart G; Yazawa, Ryosuke; Koop, Ben F; Jones, Simon R M

2014-03-15

Salmon species vary in susceptibility to infections with the salmon louse (Lepeophtheirus salmonis). Comparing mechanisms underlying responses in susceptible and resistant species is important for estimating impacts of infections on wild salmon, selective breeding of farmed salmon, and expanding our knowledge of fish immune responses to ectoparasites. Herein we report three L. salmonis experimental infection trials of co-habited Atlantic Salmo salar, chum Oncorhynchus keta and pink salmon O. gorbuscha, profiling hematocrit, blood cortisol concentrations, and transcriptomic responses of the anterior kidney and skin to the infection. In all trials, infection densities (lice per host weight (g)) were consistently highest on chum salmon, followed by Atlantic salmon, and lowest in pink salmon. At 43 days post-exposure, all lice had developed to motile stages, and infection density was uniformly low among species. Hematocrit was reduced in infected Atlantic and chum salmon, and cortisol was elevated in infected chum salmon. Systemic transcriptomic responses were profiled in all species and large differences in response functions were identified between Atlantic and Pacific (chum and pink) salmon. Pink and chum salmon up-regulated acute phase response genes, including complement and coagulation components, and down-regulated antiviral immune genes. The pink salmon response involved the largest and most diverse iron sequestration and homeostasis mechanisms. Pattern recognition receptors were up-regulated in all species but the active components were often species-specific. C-type lectin domain family 4 member M and acidic mammalian chitinase were specifically up-regulated in the resistant pink salmon. Experimental exposures consistently indicated increased susceptibility in chum and Atlantic salmon, and resistance in pink salmon, with differences in infection density occurring within the first three days of infection. Transcriptomic analysis suggested candidate resistance

Patterns of Piscirickettsia salmonis load in susceptible and resistant families of Salmo salar.

PubMed

Dettleff, Phillip; Bravo, Cristian; Patel, Alok; Martinez, Victor

2015-07-01

The pathogen Piscirickettsia salmonis produces a systemic aggressive infection that involves several organs and tissues in salmonids. In spite of the great economic losses caused by this pathogen in the Atlantic salmon (Salmo salar) industry, very little is known about the resistance mechanisms of the host to this pathogen. In this paper, for the first time, we aimed to identify the bacterial load in head kidney and muscle of Atlantic salmon exhibiting differential familiar mortality. Furthermore, in order to assess the patterns of gene expression of immune related genes in susceptible and resistant families, a set of candidate genes was evaluated using deep sequencing of the transcriptome. The results showed that the bacterial load was significantly lower in resistant fish, when compared with the susceptible individuals. Based on the candidate genes analysis, we infer that the resistant hosts triggered up-regulation of specific genes (such as for example the LysC), which may explain a decrease in the bacterial load in head kidney, while the susceptible fish presented an exacerbated innate response, which is unable to exert an effective response against the bacteria. Interestingly, we found a higher bacterial load in muscle when compared with head kidney. We argue that this is possible due to the availability of an additional source of iron in muscle. Besides, the results show that the resistant fish could not be a likely reservoir of the bacteria. Copyright © 2015 Elsevier Ltd. All rights reserved.

Establishment of two invasive crustaceans (Copepoda: Harpacticoida) on the nearshore sands of Lake Michigan

USGS Publications Warehouse

Horvath, Thomas G.; Whitman, Richard L.; Last, Laurel L.

2001-01-01

Benthic copepods (Copepoda: Harpacticoida) in the nearshore sediments of southern Lake Michigan appear to be dominated by two new invasive species. We report the first occurrence in North America of Schizopera borutzkyi Montschenko, a native to the Danube River delta, and Heteropsyllus nr. nunni, likely a new species that is morphologically similar to the marine species Heteropsyllus nunni and represents the first occurrence of this genus in freshwater. Schizopera borutzkyi is a euryhaline species occurring in shallow sands in its native habitat and in deeper sands (6-15 m) in southern Lake Michigan. Based on the absence of these species from previous studies, we suggest that they are recent introductions. Heteropsyllus nr. nunni dominated (55-100%) the harpacticoid abundance to depths of 9 m, but S. borutzkyi comprised 75% of the harpacticoid abundance at 15 m. Native harpacticoids were always greatly outnumbered by invasive harpacticoids in our samples, which suggests that the natives are being replaced rapidly or that the invasive species are finding unused resources. The ecological implications of these introductions are not known, but these invasions may represent continued 'invasional meltdown' in Lake Michigan.

Simulated environmental transport distances of Lepeophtheirus salmonis in Loch Linnhe, Scotland, for informing aquaculture area management structures.

PubMed

Salama, N K G; Murray, A G; Rabe, B

2016-04-01

In the majority of salmon farming countries, production occurs in zones where practices are coordinated to manage disease agents such as Lepeophtheirus salmonis. To inform the structure of zones in specific systems, models have been developed accounting for parasite biology and system hydrodynamics. These models provide individual system farm relationships, and as such, it may be beneficial to produce more generalized principles for informing structures. Here, we use six different forcing scenarios to provide simulations from a previously described model of the Loch Linnhe system, Scotland, to assess the maximum dispersal distance of lice particles released from 12 sites transported over 19 day. Results indicate that the median distance travelled is 6.1 km from release site with <2.5% transported beyond 15 km, which occurs from particles originating from half of the release sites, with an absolute simulated distance of 36 km observed. This provides information suggesting that the disease management areas developed for infectious salmon anaemia control may also have properties appropriate for salmon lice management in Scottish coastal waters. Additionally, general numerical descriptors of the simulated relative lice abundance reduction with increased distance from release location are proposed. © 2015 Crown copyright. © 2015 John Wiley & Sons Ltd.

A new species of Caligus Müller, 1785 (Copepoda: Siphonostomatoida: Caligidae) from coral reef plankton in the Mexican Caribbean.

PubMed

Suárez-Morales, Eduardo; Gasca, Rebeca

2016-10-11

During a survey of the zooplankton community of a protected reef system on the southern coast of the Mexican Caribbean, many female and male specimens of an undescribed species of Caligus Müller, 1785 were collected. The new species closely resembles C. wilsoni Delamare Deboutteville & Nunez-Ruivo, 1958 and C. belones (Krøyer, 1863) and has affinities with C. balistae Steenstrup & Lütken, 1861 and C. longipedis Bassett-Smith, 1898, all known from the Caribbean Sea and adjacent waters of the north-western Atlantic Ocean. Caligus ilhoikimi sp. nov., is described in full and illustrations of both sexes are also provided. The new species differs from C. wilsoni and C. belones in several features, including the shape of the sternal furca, the shape and proportions of the genital complex and abdomen, the lack of accessory processes on the distal elements of leg 1 exopod, and the presence of a lateral spine on the third exopodal segment of leg 2. This is the seventh species of Caligus known from waters of the Atlantic seaboard of Mexico and the 32nd species of the genus recorded in Mexican waters. The specimens were caught with a plankton light trap. The unusually high number of individuals captured and the fact that the sample was monospecific (i.e. only adults of this caligid species were collected) suggests that it is a chiefly planktonic form. This is a mode of life recently revealed as being more common among caligids than previously thought.

Space-time cluster analysis of sea lice infestation (Caligus clemensi and Lepeophtheirus salmonis) on wild juvenile Pacific salmon in the Broughton Archipelago of Canada.

PubMed

Patanasatienkul, Thitiwan; Sanchez, Javier; Rees, Erin E; Pfeiffer, Dirk; Revie, Crawford W

2015-06-15

Sea lice infestation levels on wild chum and pink salmon in the Broughton Archipelago region are known to vary spatially and temporally; however, the locations of areas associated with a high infestation level had not been investigated yet. In the present study, the multivariate spatial scan statistic based on a Poisson model was used to assess spatial clustering of elevated sea lice (Caligus clemensi and Lepeophtheirus salmonis) infestation levels on wild chum and pink salmon sampled between March and July of 2004 to 2012 in the Broughton Archipelago and Knight Inlet regions of British Columbia, Canada. Three covariates, seine type (beach and purse seining), fish size, and year effect, were used to provide adjustment within the analyses. The analyses were carried out across the five months/datasets and between two fish species to assess the consistency of the identified clusters. Sea lice stages were explored separately for the early life stages (non-motile) and the late life stages of sea lice (motile). Spatial patterns in fish migration were also explored using monthly plots showing the average number of each fish species captured per sampling site. The results revealed three clusters for non-motile C. clemensi, two clusters for non-motile L. salmonis, and one cluster for the motile stage in each of the sea lice species. In general, the location and timing of clusters detected for both fish species were similar. Early in the season, the clusters of elevated sea lice infestation levels on wild fish are detected in areas closer to the rivers, with decreasing relative risks as the season progresses. Clusters were detected further from the estuaries later in the season, accompanied by increasing relative risks. In addition, the plots for fish migration exhibit similar patterns for both fish species in that, as expected, the juveniles move from the rivers toward the open ocean as the season progresses The identification of space-time clustering of infestation on wild

Physiological consequences of the salmon louse (Lepeophtheirus salmonis) on juvenile pink salmon (Oncorhynchus gorbuscha): implications for wild salmon ecology and management, and for salmon aquaculture.

PubMed

Brauner, C J; Sackville, M; Gallagher, Z; Tang, S; Nendick, L; Farrell, A P

2012-06-19

Pink salmon, Oncorhynchus gorbuscha, are the most abundant wild salmon species and are thought of as an indicator of ecosystem health. The salmon louse, Lepeophtheirus salmonis, is endemic to pink salmon habitat but these ectoparasites have been implicated in reducing local pink salmon populations in the Broughton Archipelago, British Columbia. This allegation arose largely because juvenile pink salmon migrate past commercial open net salmon farms, which are known to incubate the salmon louse. Juvenile pink salmon are thought to be especially sensitive to this ectoparasite because they enter the sea at such a small size (approx. 0.2 g). Here, we describe how 'no effect' thresholds for salmon louse sublethal impacts on juvenile pink salmon were determined using physiological principles. These data were accepted by environmental managers and are being used to minimize the impact of salmon aquaculture on wild pink salmon populations.

Phylogenetic Information Content of Copepoda Ribosomal DNA Repeat Units: ITS1 and ITS2 Impact

PubMed Central

Zagoskin, Maxim V.; Lazareva, Valentina I.; Grishanin, Andrey K.; Mukha, Dmitry V.

2014-01-01

The utility of various regions of the ribosomal repeat unit for phylogenetic analysis was examined in 16 species representing four families, nine genera, and two orders of the subclass Copepoda (Crustacea). Fragments approximately 2000 bp in length containing the ribosomal DNA (rDNA) 18S and 28S gene fragments, the 5.8S gene, and the internal transcribed spacer regions I and II (ITS1 and ITS2) were amplified and analyzed. The DAMBE (Data Analysis in Molecular Biology and Evolution) software was used to analyze the saturation of nucleotide substitutions; this test revealed the suitability of both the 28S gene fragment and the ITS1/ITS2 rDNA regions for the reconstruction of phylogenetic trees. Distance (minimum evolution) and probabilistic (maximum likelihood, Bayesian) analyses of the data revealed that the 28S rDNA and the ITS1 and ITS2 regions are informative markers for inferring phylogenetic relationships among families of copepods and within the Cyclopidae family and associated genera. Split-graph analysis of concatenated ITS1/ITS2 rDNA regions of cyclopoid copepods suggested that the Mesocyclops, Thermocyclops, and Macrocyclops genera share complex evolutionary relationships. This study revealed that the ITS1 and ITS2 regions potentially represent different phylogenetic signals. PMID:25215300

Morphometric variability of Arctodiaptomus salinus (Copepoda) in the Mediterranean-Black Sea region

PubMed Central

ANUFRIIEVA, Elena V.; SHADRIN, Nickolai V.

2015-01-01

Inter-species variability in morphological traits creates a need to know the range of variability of characteristics in the species for taxonomic and ecological tasks. Copepoda Arctodiaptomus salinus, which inhabits water bodies across Eurasia and North Africa, plays a dominant role in plankton of different water bodies-from fresh to hypersaline. This work assesses the intra- and inter-population morphometric variability of A. salinus in the Mediterranean-Black Sea region and discusses some observed regularities. The variability of linear body parameters and proportions was studied. The impacts of salinity, temperature, and population density on morphological characteristics and their variability can manifest themselves in different ways at the intra- and inter-population levels. A significant effect of salinity, pH and temperature on the body proportions was not found. Their intra-population variability is dependent on temperature and salinity. Sexual dimorphism of A. salinus manifests in different linear parameters, proportions, and their variability. There were no effects of temperature, pH and salinity on the female/male parameter ratio. There were significant differences in the body proportions of males and females in different populations. The influence of temperature, salinity, and population density can be attributed to 80%-90% of intra-population variability of A. salinus. However, these factors can explain less than 40% of inter-population differences. Significant differences in the body proportions of males and females from different populations may suggest that some local populations of A. salinus in the Mediterranean-Black Sea region are in the initial stages of differentiation. PMID:26646569

Morphometric variability of Arctodiaptomus salinus (Copepoda) in the Mediterranean-Black Sea region.

PubMed

Anufriieva, Elena V; Shadrin, Nickolai V

2015-11-18

Inter-species variability in morphological traits creates a need to know the range of variability of characteristics in the species for taxonomic and ecological tasks. Copepoda Arctodiaptomus salinus, which inhabits water bodies across Eurasia and North Africa, plays a dominant role in plankton of different water bodies-from fresh to hypersaline. This work assesses the intra- and inter-population morphometric variability of A. salinus in the Mediterranean-Black Sea region and discusses some observed regularities. The variability of linear body parameters and proportions was studied. The impacts of salinity, temperature, and population density on morphological characteristics and their variability can manifest themselves in different ways at the intra- and inter-population levels. A significant effect of salinity, pH and temperature on the body proportions was not found. Their intra-population variability is dependent on temperature and salinity. Sexual dimorphism of A. salinus manifests in different linear parameters, proportions, and their variability. There were no effects of temperature, pH and salinity on the female/male parameter ratio. There were significant differences in the body proportions of males and females in different populations. The influence of temperature, salinity, and population density can be attributed to 80%-90% of intra-population variability of A. salinus. However, these factors can explain less than 40% of inter-population differences. Significant differences in the body proportions of males and females from different populations may suggest that some local populations of A. salinus in the Mediterranean-Black Sea region are in the initial stages of differentiation.

Gene silencing reveals multiple functions of Na+/K+-ATPase in the salmon louse (Lepeophtheirus salmonis).

PubMed

Komisarczuk, Anna Z; Kongshaug, Heidi; Nilsen, Frank

2018-02-01

Na + /K + -ATPase has a key function in a variety of physiological processes including membrane excitability, osmoregulation, regulation of cell volume, and transport of nutrients. While knowledge about Na + /K + -ATPase function in osmoregulation in crustaceans is extensive, the role of this enzyme in other physiological and developmental processes is scarce. Here, we report characterization, transcriptional distribution and likely functions of the newly identified L. salmonis Na + /K + -ATPase (LsalNa + /K + -ATPase) α subunit in various developmental stages. The complete mRNA sequence was identified, with 3003 bp open reading frame encoding a putative protein of 1001 amino acids. Putative protein sequence of LsalNa + /K + -ATPase revealed all typical features of Na + /K + -ATPase and demonstrated high sequence identity to other invertebrate and vertebrate species. Quantitative RT-PCR analysis revealed higher LsalNa + /K + -ATPase transcript level in free-living stages in comparison to parasitic stages. In situ hybridization analysis of copepodids and adult lice revealed LsalNa + /K + -ATPase transcript localization in a wide variety of tissues such as nervous system, intestine, reproductive system, and subcuticular and glandular tissue. RNAi mediated knock-down of LsalNa + /K + -ATPase caused locomotion impairment, and affected reproduction and feeding. Morphological analysis of dsRNA treated animals revealed muscle degeneration in larval stages, severe changes in the oocyte formation and maturation in females and abnormalities in tegmental glands. Thus, the study represents an important foundation for further functional investigation and identification of physiological pathways in which Na + /K + -ATPase is directly or indirectly involved. Copyright © 2018 Elsevier Inc. All rights reserved.

Combinatorial effects of administration of immunostimulatory compounds in feed and follow-up administration of triple-dose SLICE® (emamectin benzoate) on Atlantic salmon, Salmo salar L., infection with Lepeophtheirus salmonis.

PubMed

Poley, J; Purcell, S L; Igboeli, O O; Donkin, A; Wotton, H; Fast, M D

2013-03-01

Several immunostimulatory feed additives have shown the ability to induce protective responses in Atlantic salmon to infection with Lepeophtheirus salmonis. However, even the most encouraging results rarely surpass a 50% protective index in the host. That fact coupled with the well-documented limitations of single-therapy strategies in the effective management of parasitic infections generally make it imperative to identify therapies that can be combined in an integrated pest management approach for sea lice. With this in mind, we hypothesized that immunostimulatory feeds could enhance the protection provided by SLICE® emamectin benzoate (EMB). To test this hypothesis, Atlantic salmon were fed one of two different immunostimulatory feeds (CpG ODN or Aquate®) for c. 7 weeks, challenged with L. salmonis copepodids early within that immunostimulatory feed period and then placed on a triple-dose (150 μg kg(-1) ) feed of SLICE® for 1 week following the completion of the immunostimulatory feeding period. CpG ODN (2 mg kg(-1) ) and the commercial yeast extract (Aquate® 0.2%) inclusion in feeds were able to successfully induce inflammatory gene expression (interleukin-1β) in the head kidneys of infected fish at 13 and 26 days post-exposure (DPE), and 13 DPE, respectively. Lice burdens were lower on fish fed CpG ODN (18%) or Aquate® (19%) diets; however, due to variability, these were not statistically significant over time. Despite no statistically significant reductions in lice numbers, by 33 DPE fish on immunostimulatory feeds had significantly reduced cortisol levels when compared to infected fish on control diet. Cortisol levels in fish receiving an immunostimulatory diet were no different from initial baseline levels prior to infection, whereas the levels in control diet fish were significantly elevated from all other time points. Despite the positive effects on infection of fish fed immunostimulatory feeds, no synergism was observed with follow-up treatment

The discovery of Caligus temnodontis Brian, 1924 (Copepoda: Caligidae) from the bluefish Pomatomus saltatrix (Linnaeus) in the eastern Mediterranean Sea.

PubMed

Ozak, Argun A; El-Rashidy, Hoda H; Demirkale, Ibrahim; Boxshall, Geoff A

2010-07-01

The temnodontis variety of Caligus mauritanicus Brian, 1924 described by Brian (1924) is a valid species known only from a single host species, Pomatomus saltatrix (Linnaeus). New material of this species has been examined from the same host fish caught from Abuqir Bay, Alexandria (Egypt), from Iskenderun Bay (Turkey) and from off the coast of South Africa. Using this material, C. temnodontis Brian, 1924 is redescribed and compared with related species. It is most closely related to the Indo-Pacific species C. pagrosomi Yamaguti, 1939.

Gill metazoan parasites of the spotted goatfish Pseudupeneus maculatus (Ostheichthyes: Mullidae) from the Coast of Pernambuco, northeastern Brazil.

PubMed

Cardoso, L; Lacerda, A C F; Gonçalves, E L T; Cadorin, D I; Bonfim, C N C; Oliveira, R L M; Martins, M L

2017-11-09

This study evaluated the parasite fauna on the gills of spotted goatfish Pseudupeneus maculatus captured in the dry and rainy seasons in the coast of the State of Pernambuco, Brazil. Eight parasite species were identified belonging to the following taxa: Monogenea (Haliotrema caraïbensis, Haliotrema caballeroi and Haliotrema golvani); Crustacea (Rocinela signata, Hamaticolax scutigerulus and Caligidae gen. sp.) and Cestoda (Nybelinia indica and Pseudolacistorhynchus noodti). The most prevalent parasites were: Monogenea (100%), H. scutigerulus (35%), N. indica (11.7%), R. signata (8.3%), Caligidae gen. sp. (3.33%) and P. noodti (0.83%). Values of infestation are compared to other studies, and the uncommon occurrence of Trypanorhyncha on the gills suggests that the spotted goatfish could be an intermediate host for the parasite.

Detection of emamectin benzoate tolerance emergence in different life stages of sea lice, Lepeophtheirus salmonis, on farmed Atlantic salmon, Salmo salar L.

PubMed

Jones, P G; Hammell, K L; Gettinby, G; Revie, C W

2013-03-01

Emamectin benzoate has been used to treat sea lice, Lepeophtheirus salmonis, infestations on farmed Atlantic salmon, Salmo salar. Recent evidence suggests a reduction in effectiveness in some locations. A major challenge in the detection of tolerance emergence can be the typically low proportion of resistant individuals in a population during the early phases. The objectives of this study were to develop a method for determining differences in temporal development of tolerance between sea lice life stages and to explore how these differences might be used to improve the monitoring of treatment effectiveness in a clinical setting. This study examined two data sets based on records of sea lice abundance following emamectin benzoate treatments from the west coast of Scotland (2002-2006) and from New Brunswick, Canada (2004-2008). Life stages were categorized into two groups (adult females and the remaining mobile stages) to examine the trends in mean abundance and treatment effectiveness. Differences in emamectin benzoate effectiveness were found between the two groups by year and location, suggesting that an important part of monitoring drug resistance development in aquatic ectoparasites may be the need to focus on key life stages. © 2013 Blackwell Publishing Ltd.

Development of the salmon louse Lepeophtheirus salmonis and its effects on juvenile sockeye salmon Oncorhynchus nerka.

PubMed

Jakob, E; Sweeten, T; Bennett, W; Jones, S R M

2013-11-06

Responses of sockeye salmon Oncorhynchus nerka during infection with Lepeophtheirus salmonis were assessed in controlled laboratory trials. Juvenile salmon were exposed to 100 copepodids fish-1 (Trials 1 and 2) or 300 copepodids fish-1 (Trial 3) at mean weights of approximately 40, 80 and 135 g, respectively. Infections occurred on all salmon in all trials, and mean abundances (infection densities) ranged between 3.3 and 19.4 lice fish-1 (0.08 and 0.44 lice g-1 fish) in Trial 1, between 7.2 and 18.3 (0.09 and 0.22) in Trial 2 and between 19.5 and 60.7 (0.15 and 0.46) in Trial 3. A cumulative mortality of 24.4% occurred in Trial 3. At attachment sites on gills, we observed hyperplasia of basal epithelial cells and fusion of secondary lamellae occasionally associated with a cellular infiltrate. At attachment sites on fins, partial to complete skin erosion occurred, with limited evidence of hyperplasia or inflammation. Scale loss and abrasions coincided with pre-adult lice around 20 d post infection (dpi). Plasma osmolality was significantly elevated in exposed fish in Trials 1 (21 dpi), 2 (15 and 36 dpi) and 3 (20 dpi), whereas haematocrit was significantly depressed in exposed fish in Trials 1 (21 and 28 dpi) and 3 (20 dpi). Plasma cortisol was significantly elevated in exposed fish at 20 dpi (Trial 3). Physiological changes and mortality were related to the intensity of infection and became most prominent with pre-adult stages, suggesting patterns of infection and response in sockeye salmon similar to those reported for Atlantic and Chinook salmon.

Ectoparasitic sea lice (Lepeophtheirus salmonis) affect behavior and brain serotonergic activity in Atlantic salmon (Salmo salar L.): Perspectives on animal welfare.

PubMed

Øverli, Øyvind; Nordgreen, Janicke; Mejdell, Cecilie M; Janczak, Andrew M; Kittilsen, Silje; Johansen, Ida B; Horsberg, Tor E

2014-06-10

Scientific research and public debate on the welfare of animals in human custody is increasing at present. Fish are in this context mentioned with particular attention to the high numbers of individuals reared in aquaculture. Research on fish has also contributed to the understanding of individual variation in the ability to cope with stress and disease. One mediator of such variation is the brain serotonergic (5-hydroxytryptamine, 5-HT) system, which conveys physiological and behavioral responses to stress and sub-optimal rearing conditions. Here we study links between the 5-HT response, melanin-based skin pigmentation, and behavior in laboratory-reared Atlantic salmon (Salmo salar) experimentally infested with ectoparasitic sea lice (Lepeophtheirus salmonis). Lice numbers were more variable in less pigmented fish, while the neurochemical response to ectoparastic lice-increased levels of the main 5-HT catabolite 5-HIAA in the brain stem-did not differ between pigmentation groups. A strong depression of growth and locomotor activity was seen in all infested fish but less pigmented fish grew better than fish with more skin melanization regardless of infestation status. The observed combination of neurochemical and behavioral effects clearly suggest that animal welfare concerns can be added to the list of negative effects of ectoparasitic sea lice. Copyright © 2014 Elsevier Inc. All rights reserved.

Molecular Systematic of Three Species of Oithona (Copepoda, Cyclopoida) from the Atlantic Ocean: Comparative Analysis Using 28S rDNA

PubMed Central

Cepeda, Georgina D.; Blanco-Bercial, Leocadio; Bucklin, Ann; Berón, Corina M.; Viñas, María D.

2012-01-01

Species of Oithona (Copepoda, Cyclopoida) are highly abundant, ecologically important, and widely distributed throughout the world oceans. Although there are valid and detailed descriptions of the species, routine species identifications remain challenging due to their small size, subtle morphological diagnostic traits, and the description of geographic forms or varieties. This study examined three species of Oithona (O. similis, O. atlantica and O. nana) occurring in the Argentine sector of the South Atlantic Ocean based on DNA sequence variation of a 575 base-pair region of 28S rDNA, with comparative analysis of these species from other North and South Atlantic regions. DNA sequence variation clearly resolved and discriminated the species, and revealed low levels of intraspecific variation among North and South Atlantic populations of each species. The 28S rDNA region was thus shown to provide an accurate and reliable means of identifying the species throughout the sampled domain. Analysis of 28S rDNA variation for additional species collected throughout the global ocean will be useful to accurately characterize biogeographical distributions of the species and to examine phylogenetic relationships among them. PMID:22558245

Taxonomic resolutions based on 18S rRNA genes: a case study of subclass copepoda.

PubMed

Wu, Shu; Xiong, Jie; Yu, Yuhe

2015-01-01

Biodiversity studies are commonly conducted using 18S rRNA genes. In this study, we compared the inter-species divergence of variable regions (V1-9) within the copepod 18S rRNA gene, and tested their taxonomic resolutions at different taxonomic levels. Our results indicate that the 18S rRNA gene is a good molecular marker for the study of copepod biodiversity, and our conclusions are as follows: 1) 18S rRNA genes are highly conserved intra-species (intra-species similarities are close to 100%); and could aid in species-level analyses, but with some limitations; 2) nearly-whole-length sequences and some partial regions (around V2, V4, and V9) of the 18S rRNA gene can be used to discriminate between samples at both the family and order levels (with a success rate of about 80%); 3) compared with other regions, V9 has a higher resolution at the genus level (with an identification success rate of about 80%); and 4) V7 is most divergent in length, and would be a good candidate marker for the phylogenetic study of Acartia species. This study also evaluated the correlation between similarity thresholds and the accuracy of using nuclear 18S rRNA genes for the classification of organisms in the subclass Copepoda. We suggest that sample identification accuracy should be considered when a molecular sequence divergence threshold is used for taxonomic identification, and that the lowest similarity threshold should be determined based on a pre-designated level of acceptable accuracy.

Taxonomic Resolutions Based on 18S rRNA Genes: A Case Study of Subclass Copepoda

PubMed Central

Wu, Shu; Xiong, Jie; Yu, Yuhe

2015-01-01

Biodiversity studies are commonly conducted using 18S rRNA genes. In this study, we compared the inter-species divergence of variable regions (V1–9) within the copepod 18S rRNA gene, and tested their taxonomic resolutions at different taxonomic levels. Our results indicate that the 18S rRNA gene is a good molecular marker for the study of copepod biodiversity, and our conclusions are as follows: 1) 18S rRNA genes are highly conserved intra-species (intra-species similarities are close to 100%); and could aid in species-level analyses, but with some limitations; 2) nearly-whole-length sequences and some partial regions (around V2, V4, and V9) of the 18S rRNA gene can be used to discriminate between samples at both the family and order levels (with a success rate of about 80%); 3) compared with other regions, V9 has a higher resolution at the genus level (with an identification success rate of about 80%); and 4) V7 is most divergent in length, and would be a good candidate marker for the phylogenetic study of Acartia species. This study also evaluated the correlation between similarity thresholds and the accuracy of using nuclear 18S rRNA genes for the classification of organisms in the subclass Copepoda. We suggest that sample identification accuracy should be considered when a molecular sequence divergence threshold is used for taxonomic identification, and that the lowest similarity threshold should be determined based on a pre-designated level of acceptable accuracy. PMID:26107258

A fixed-dose approach to conducting emamectin benzoate tolerance assessments on field-collected sea lice, Lepeophtheirus salmonis.

PubMed

Whyte, S K; Westcott, J D; Elmoslemany, A; Hammell, K L; Revie, C W

2013-03-01

In New Brunswick, Canada, the sea louse, Lepeophtheirus salmonis, poses an on-going management challenge to the health and productivity of commercially cultured Atlantic salmon, Salmo salar. While the in-feed medication, emamectin benzoate (SLICE® ; Merck), has been highly effective for many years, evidence of increased tolerance has been observed in the field since late 2008. Although bioassays on motile stages are a common tool to monitor sea lice sensitivity to emamectin benzoate in field-collected sea lice, they require the collection of large numbers of sea lice due to inherent natural variability in the gender and stage response to chemotherapeutants. In addition, sensitive instruments such as EC(50) analysis may be unnecessarily complex to characterize susceptibility subsequent to a significant observed decline in efficacy. This study proposes an adaptation of the traditional, dose-response format bioassay to a fixed-dose method. Analysis of 657 bioassays on preadult and adult stages of sea lice over the period 2008-2011 indicated a population of sea lice in New Brunswick with varying degrees of susceptibility to emamectin benzoate. A seasonal and spatial effect was observed in the robustness of genders and stages of sea lice, which suggest that mixing different genders and stages of lice within a single bioassay may result in pertinent information being overlooked. Poor survival of adult female lice in bioassays, particularly during May/June, indicates it may be prudent to consider excluding this stage from bioassays conducted at certain times of the year. This work demonstrates that fixed-dose bioassays can be a valuable technique in detecting reduced sensitivity in sea lice populations with varying degrees of susceptibility to emamectin benzoate treatments. © 2013 Blackwell Publishing Ltd.

Macroevolutionary patterns of sexual size dimorphism in copepods

PubMed Central

Hirst, Andrew G.; Kiørboe, Thomas

2014-01-01

Major theories compete to explain the macroevolutionary trends observed in sexual size dimorphism (SSD) in animals. Quantitative genetic theory suggests that the sex under historically stronger directional selection will exhibit greater interspecific variance in size, with covariation between allometric slopes (male to female size) and the strength of SSD across clades. Rensch's rule (RR) also suggests a correlation, but one in which males are always the more size variant sex. Examining free-living pelagic and parasitic Copepoda, we test these competing predictions. Females are commonly the larger sex in copepod species. Comparing clades that vary by four orders of magnitude in their degree of dimorphism, we show that isometry is widespread. As such we find no support for either RR or for covariation between allometry and SSD. Our results suggest that selection on both sexes has been equally important. We next test the prediction that variation in the degree of SSD is related to the adult sex ratio. As males become relatively less abundant, it has been hypothesized that this will lead to a reduction in both inter-male competition and male size. However, the lack of such a correlation across diverse free-living pelagic families of copepods provides no support for this hypothesis. By comparison, in sea lice of the family Caligidae, there is some qualitative support of the hypothesis, males may suffer elevated mortality when they leave the host and rove for sedentary females, and their female-biased SSD is greater than in many free-living families. However, other parasitic copepods which do not appear to have obvious differences in sex-based mate searching risks also show similar or even more extreme SSD, therefore suggesting other factors can drive the observed extremes. PMID:25100692

Host specificity of Lepeophtheirus crassus (Wilson and Bere) (Copepoda: Caligidae) parasitic on the marlin sucker Remora osteochir (Cuvier) in the Atlantic Ocean.

PubMed

Ho, Ju-shey; Collete, Bruce B; Madinabeitia, Ione

2006-10-01

Three species of remoras--Remora brachyptera (Lowe), Remora osteochir (Cuvier), and Remora remora (Linnaeus)--were collected from 4 species of billfishes--Istiophorus platypterus (Shaw), Makaira nigricans Lacepéde, Tetrapturus albidus Poey, and Tetrapturus pfluegeri Robins and de Sylva--on board a Japanese long-liner Shoyo Maru during her cruise in 2002 across the Atlantic. However, only the marlin sucker (R. osteochir) was found to carry a parasitic copepod, Lepeophtheirus crassus (Wilson and Bere, 1936). Although 12 species of parasitic copepods have been reported from billfishes around the world ocean, none of them is L. crassus. Thus, L. crassus is considered a parasite specific to the marlin sucker.

Optimization and field use of a bioassay to monitor sea lice Lepeophtheirus salmonis sensitivity to emamectin benzoate.

PubMed

Westcott, Jillian D; Stryhn, Henrik; Burka, John F; Hammell, K Larry

2008-04-01

A bioassay for sea lice Lepeophtheirus salmonis sensitivity towards emamectin benzoate (EMB) was validated for field use. A probit regression model with natural responsiveness was used for the number of affected (moribund or dead) sea lice in bioassays involving different concentrations of EMB. Bioassay optimization included an evaluation of the inter-rater reliability of sea lice responsiveness to EMB and an evaluation of gender-related differences in susceptibility. Adoption of a set of bioassay response criteria improved the concordance (evaluated using the concordance correlation coefficient) between raters' assessments and the model estimation of EC50 values (the 'effective concentration' leading to a response of 50% of the lice not prone to natural response). An evaluation of gender-related differences in EMB susceptibility indicated that preadult stage female sea lice exhibited a significantly larger sensitivity towards EMB in 12 of 19 bioassays compared to preadult males. In order to evaluate sea lice sensitivity to EMB in eastern Canada, the intensive salmon farming area in the Bay of Fundy in southwestern New Brunswick was divided into 4 distinct regions based on industry health management practices and hydrographics. A total of 38 bioassays were completed from 2002 to 2005 using populations of preadult stage sea lice collected from Atlantic salmon Salmo salar farms within the 4 described regions. There was no significant overall effect of region or year on EC50 values; however, analysis of variance indicated a significant effect of time of year on EC50 values in 2002 and a potential effect in 2004 to 2005. Although the range of EC50 values obtained in this 3 yr study did not appear sufficient to affect current clinical success in the control of sea lice, the results suggest a seasonal- or temperature-associated variation in sensitivity to EMB. This will need to be considered if changes in EMB efficacy occur in the future.

Enhanced transcriptomic responses in the Pacific salmon louse Lepeophtheirus salmonis oncorhynchi to the non-native Atlantic Salmon Salmo salar suggests increased parasite fitness.

PubMed

Braden, Laura M; Sutherland, Ben J G; Koop, Ben F; Jones, Simon R M

2017-01-30

Outcomes of infections with the salmon louse Lepeophtheirus salmonis vary considerably among its natural hosts (Salmo, Oncorhynchus spp.). Host-parasite interactions range from weak to strong host responses accompanied by high to low parasite abundances, respectively. Parasite behavioral studies indicate that the louse prefers the host Atlantic Salmon (Salmo salar), which is characterized by a weak immune response, and that this results in enhanced parasite reproduction and growth rates. Furthermore, parasite-derived immunosuppressive molecules (e.g., proteases) have been detected at higher amounts in response to the mucus of Atlantic Salmon relative to Coho Salmon (Oncorhynchus kisutch). However, the host-specific responses of the salmon louse have not been well characterized in either of the genetically distinct sub-species that occur in the Atlantic and Pacific Oceans. We assessed and compared the transcriptomic feeding response of the Pacific salmon louse (L. salmonis oncorhynchi,) while parasitizing the highly susceptible Atlantic Salmon and Sockeye Salmon (Oncorhynchus nerka) or the more resistant Coho Salmon (Oncorhynchus kisutch) using a 38 K oligonucleotide microarray. The response of the louse was enhanced both in the number of overexpressed genes and in the magnitude of expression while feeding on the non-native Atlantic Salmon, compared to either Coho or Sockeye Salmon. For example, putative virulence factors (e.g., cathepsin L, trypsin, carboxypeptidase B), metabolic enzymes (e.g., cytochrome B, cytochrome C), protein synthesis enzymes (e.g., ribosomal protein P2, 60S ribosomal protein L7), and reproduction-related genes (e.g., estrogen sulfotransferase) were overexpressed in Atlantic-fed lice, indicating heightened parasite fitness with this host species. In contrast, responses in Coho- or Sockeye-fed lice were more similar to those of parasites deprived of a host. To test for host acclimation by the parasite, we performed a reciprocal host transfer

The efficacy of emamectin benzoate against infestations of Lepeophtheirus salmonis on farmed Atlantic salmon (Salmo salar L) in Scotland, 2002-2006.

PubMed

Lees, Fiona; Baillie, Mark; Gettinby, George; Revie, Crawford W

2008-02-06

Infestations of the parasitic copepod Lepeophtheirus salmonis, commonly referred to as sea lice, represent a major challenge to commercial salmon aquaculture. Dependence on a limited number of theraputants to control such infestations has led to concerns of reduced sensitivity in some sea lice populations. This study investigates trends in the efficacy of the in-feed treatment emamectin benzoate in Scotland, the active ingredient most widely used across all salmon producing regions. Study data were drawn from over 50 commercial Atlantic salmon farms on the west coast of Scotland between 2002 and 2006. An epi-informatics approach was adopted whereby available farm records, descriptive epidemiological summaries and statistical linear modelling methods were used to identify factors that significantly affect sea lice abundance following treatment with emamectin benzoate (SLICE(R), Schering Plough Animal Health). The results show that although sea lice infestations are reduced following the application of emamectin benzoate, not all treatments are effective. Specifically there is evidence of variation across geographical regions and a reduction in efficacy over time. Reduced sensitivity and potential resistance to currently available medicines are constant threats to maintaining control of sea lice populations on Atlantic salmon farms. There is a need for on-going monitoring of emamectin benzoate treatment efficacy together with reasons for any apparent reduction in performance. In addition, strategic rotation of medicines should be encouraged and empirical evidence for the benefit of such strategies more fully evaluated.

Advances in Taxonomy, Ecology, and Biogeography of Dirivultidae (Copepoda) Associated with Chemosynthetic Environments in the Deep Sea

PubMed Central

Gollner, Sabine; Ivanenko, Viatcheslav N.; Arbizu, Pedro Martínez; Bright, Monika

2010-01-01

Background Copepoda is one of the most prominent higher taxa with almost 80 described species at deep-sea hydrothermal vents. The unique copepod family Dirivultidae with currently 50 described species is the most species rich invertebrate family at hydrothermal vents. Methodology/Principal Findings We reviewed the literature of Dirivultidae and provide a complete key to species, and map geographical and habitat specific distribution. In addition we discuss the ecology and origin of this family. Conclusions/Significance Dirivultidae are only present at deep-sea hydrothermal vents and along the axial summit trough of midocean ridges, with the exception of Dirivultus dentaneus found associated with Lamellibrachia species at 1125 m depth off southern California. To our current knowledge Dirivultidae are unknown from shallow-water vents, seeps, whale falls, and wood falls. They are a prominent part of all communities at vents and in certain habitat types (like sulfide chimneys colonized by pompei worms) they are the most abundant animals. They are free-living on hard substrate, mostly found in aggregations of various foundation species (e.g. alvinellids, vestimentiferans, and bivalves). Most dirivultid species colonize more than one habitat type. Dirivultids have a world-wide distribution, but most genera and species are endemic to a single biogeographic region. Their origin is unclear yet, but immigration from other deep-sea chemosynthetic habitats (stepping stone hypothesis) or from the deep-sea sediments seems unlikely, since Dirivultidae are unknown from these environments. Dirivultidae is the most species rich family and thus can be considered the most successful taxon at deep-sea vents. PMID:20838422

A new species of Pseudomacrochiron Reddiah, 1969 (Crustacea: Copepoda: Macrochironidae) associated with scyphistomae of the moon jellyfish Aurelia sp. (Cnidaria: Scyphozoa) off Japan.

PubMed

Tang, Danny; Yasuda, Akira; Yamada, Satoshi; Nagasawa, Kazuya

2012-02-01

A new species of the Macrochironidae Humes & Boxshall, 1996 (Copepoda: Cyclopoida), Pseudomacrochiron aureliae n. sp., is described based on adult specimens extracted from the gastrovacular cavity of the scyphistomae of Aurelia sp. (Cnidaria: Scyphozoa) collected in the Seto Inland Sea and Ise Bay off the coast of Japan. The new species differs from its congeners by having the following combination of characters: a caudal ramus with a length to width ratio of 3.1; an accessory flagellum on caudal setae II, III and VI; three apical setae on the maxillule; only setae I and II on the maxillary basis; two short spines on the female maxilliped claw (endopod); an armature of III, I, 4 on the terminal exopodal segment of leg 3; an armature of I, II, 2 on the terminal endopodal segment of leg 3; an armature of II, I, 4 on the terminal exopodal segment of leg 4; and a short free exopodal segment of leg 5 (length to width ratio of 1.4) armed with a long seta and short spine. P. aureliae n. sp. is the first member of the genus reported from off Japan and from the scyphistomae of its scyphozoan host.

The complete genome sequence of CrRV-Ch01, a new member of the family Rhabdoviridae in the parasitic copepod Caligus rogercresseyi present on farmed Atlantic salmon (Salmo salar) in Chile.

PubMed

Økland, Arnfinn Lodden; Skoge, Renate Hvidsten; Nylund, Are

2018-06-01

We have determined the complete genome sequence of a new rhabdovirus, tentatively named Caligus rogercresseyi rhabdovirus Ch01 (CrRV-Ch01), which was found in the parasite Caligus rogercresseyi, present on farmed Atlantic salmon (Salmo salar) in Chile. The genome encodes the five canonical rhabdovirus proteins in addition to an unknown protein, in the order N-P-M-U (unknown)-G-L. Phylogenetic analysis showed that the virus clusters with two rhabdoviruses (Lepeophtheirus salmonis rhabdovirus No9 and Lepeophtheirus salmonis rhabdovirus No127) obtained from another parasitic caligid, Lepeophtheirus salmonis, present on farmed Atlantic salmon on the west coast of Norway.

The Efficacy of Emamectin Benzoate against Infestations of Lepeophtheirus salmonis on Farmed Atlantic Salmon (Salmo salar L) in Scotland, 2002–2006

PubMed Central

Lees, Fiona; Baillie, Mark; Gettinby, George; Revie, Crawford W.

2008-01-01

Background Infestations of the parasitic copepod Lepeophtheirus salmonis, commonly referred to as sea lice, represent a major challenge to commercial salmon aquaculture. Dependence on a limited number of theraputants to control such infestations has led to concerns of reduced sensitivity in some sea lice populations. This study investigates trends in the efficacy of the in-feed treatment emamectin benzoate in Scotland, the active ingredient most widely used across all salmon producing regions. Methodology/Principal Findings Study data were drawn from over 50 commercial Atlantic salmon farms on the west coast of Scotland between 2002 and 2006. An epi-informatics approach was adopted whereby available farm records, descriptive epidemiological summaries and statistical linear modelling methods were used to identify factors that significantly affect sea lice abundance following treatment with emamectin benzoate (SLICE®, Schering Plough Animal Health). The results show that although sea lice infestations are reduced following the application of emamectin benzoate, not all treatments are effective. Specifically there is evidence of variation across geographical regions and a reduction in efficacy over time. Conclusions/Significance Reduced sensitivity and potential resistance to currently available medicines are constant threats to maintaining control of sea lice populations on Atlantic salmon farms. There is a need for on-going monitoring of emamectin benzoate treatment efficacy together with reasons for any apparent reduction in performance. In addition, strategic rotation of medicines should be encouraged and empirical evidence for the benefit of such strategies more fully evaluated. PMID:18253496

Sea lice levels on wild Atlantic salmon, Salmo salar L., returning to the coast of Ireland.

PubMed

Jackson, D; Kane, F; O'Donohoe, P; Mc Dermott, T; Kelly, S; Drumm, A; Newell, J

2013-03-01

The sea lice population structure, prevalence and intensity of Lepeophtheirus salmonis have been studied over a period extending from 2004 to 2011. Infestation data were collected from the interceptor drift net fishery from 2004 until it was closed in 2006. From 2010, data were collected from the inshore draft net fishery. In all, 34 samples from the drift and draft net fisheries have been analysed to date. Prevalence of infestation with L. salmonis regularly approached 100% in samples of hosts recovered from the offshore drift net fishery. Abundance was variable both within and between years with a maximum mean abundance of 25.8 lice per fish recorded in 2004. The population structure of L. salmonis on hosts recovered in the inshore and estuarine draft net fisheries was different from that observed in the more offshore drift net samples. There is clear evidence of recent infestation with L. salmonis in the draft net samples. © 2013 Blackwell Publishing Ltd.

Molecular characterization and functional analysis of a salmon louse (Lepeophtheirus salmonis, Krøyer 1838) heme peroxidase with a potential role in extracellular matrixes.

PubMed

Øvergård, Aina-Cathrine; Eichner, Christiane; Nilsen, Frank; Dalvin, Sussie

2017-04-01

Heme peroxidases are the most abundant type of peroxidase catalyzing a H 2 O 2 -dependent oxidation of a wide variety of substrates. They are involved in numerous processes like the innate immune response, hormone and prostaglandin synthesis and crosslinking of proteins within extracellular matrixes (ECM) as well as molecules within the cuticle and chorion of arthropods and nematodes. In the present study, a Lepeophtheirus salmonis heme peroxidase (LsHPX) 1 was characterized. Amino acids in the active site of heme peroxidases were conserved, and the predicted protein sequence showed the highest similarity to genes annotated as chorion peroxidases and genes suggested to be involved in cuticle hardening or adhesion. LsHPX1 exhibited a dynamic expression during ontogenesis and during the nauplius molting cycle. Transcripts were localized to muscle cells near the muscle-tendon junction, in nerve tissue especially at neuromuscular junctions, subcuticular epithelium, subepithelial cells facing the hemolymph, exocrine glands within the subepithelial tissue and in isolated cells within the testis. Knock-down of LsHPX1 in nauplius larvae decreased the swimming activity of emerging copepodids. Histological analysis of knock-down animals revealed increased spacing between myofibers and changes in subepithelial and exocrine gland tissue. Considering these results, the potential role of LsHPX1 in crosslinking molecules of salmon louse ECMs is discussed. Copyright © 2017 Elsevier Inc. All rights reserved.

Multi-Gene Analysis Reveals a Lack of Genetic Divergence between Calanus agulhensis and C. sinicus (Copepoda; Calanoida)

PubMed Central

Kozol, Robert; Blanco-Bercial, Leocadio; Bucklin, Ann

2012-01-01

The discrimination and taxonomic identification of marine species continues to pose a challenge despite the growing number of diagnostic metrics and approaches. This study examined the genetic relationship between two sibling species of the genus Calanus (Crustacea; Copepoda; Calanidae), C. agulhensis and C. sinicus, using a multi-gene analysis. DNA sequences were determined for portions of the mitochondrial cytochrome c oxidase I (mtCOI); nuclear citrate synthase (CS), and large subunit (28S) rRNA genes for specimens collected from the Sea of Japan and North East (NE) Pacific Ocean for C. sinicus and from the Benguela Current and Agulhas Bank, off South Africa, for C. agulhensis. For mtCOI, C. sinicus and C. agulhensis showed similar levels of haplotype diversity (Hd = 0.695 and 0.660, respectively) and nucleotide diversity (π = 0.003 and 0.002, respectively). Pairwise FST distances for mtCOI were significant only between C. agulhensis collected from the Agulhas and two C. sinicus populations: the Sea of Japan (FST = 0.152, p<0.01) and NE Pacific (FST = 0.228, p<0.005). Between the species, FST distances were low for both mtCOI (FST = 0.083, p = 0.003) and CS (FST = 0.050, p = 0.021). Large subunit (28S) rRNA showed no variation between the species. Our results provide evidence of the lack of genetic distinction of C. sinicus and C. agulhensis, raise questions of whether C. agulhensis warrants status as a distinct species, and indicate the clear need for more intensive and extensive ecological and genetic analysis. PMID:23118849

Genomic characterization and phylogenetic position of two new species in Rhabdoviridae infecting the parasitic copepod, salmon louse (Lepeophtheirus salmonis).

PubMed

Økland, Arnfinn Lodden; Nylund, Are; Øvergård, Aina-Cathrine; Blindheim, Steffen; Watanabe, Kuninori; Grotmol, Sindre; Arnesen, Carl-Erik; Plarre, Heidrun

2014-01-01

Several new viruses have emerged during farming of salmonids in the North Atlantic causing large losses to the industry. Still the blood feeding copepod parasite, Lepeophtheirus salmonis, remains the major challenge for the industry. Histological examinations of this parasite have revealed the presence of several virus-like particles including some with morphologies similar to rhabdoviruses. This study is the first description of the genome and target tissues of two new species of rhabdoviruses associated with pathology in the salmon louse. Salmon lice were collected at different Atlantic salmon (Salmo salar) farming sites on the west coast of Norway and prepared for histology, transmission electron microscopy and Illumina sequencing of the complete RNA extracted from these lice. The nearly complete genomes, around 11,600 nucleotides encoding the five typical rhabdovirus genes N, P, M, G and L, of two new species were obtained. The genome sequences, the putative protein sequences, and predicted transcription strategies for the two viruses are presented. Phylogenetic analyses of the putative N and L proteins indicated closest similarity to the Sigmavirus/Dimarhabdoviruses cluster, however, the genomes of both new viruses are significantly diverged with no close affinity to any of the existing rhabdovirus genera. In situ hybridization, targeting the N protein genes, showed that the viruses were present in the same glandular tissues as the observed rhabdovirus-like particles. Both viruses were present in all developmental stages of the salmon louse, and associated with necrosis of glandular tissues in adult lice. As the two viruses were present in eggs and free-living planktonic stages of the salmon louse vertical, transmission of the viruses are suggested. The tissues of the lice host, Atlantic salmon, with the exception of skin at the attachment site for the salmon louse chalimi stages, were negative for these two viruses.

Genomic Characterization and Phylogenetic Position of Two New Species in Rhabdoviridae Infecting the Parasitic Copepod, Salmon Louse (Lepeophtheirus salmonis)

PubMed Central

Økland, Arnfinn Lodden; Nylund, Are; Øvergård, Aina-Cathrine; Blindheim, Steffen; Watanabe, Kuninori; Grotmol, Sindre; Arnesen, Carl-Erik; Plarre, Heidrun

2014-01-01

Several new viruses have emerged during farming of salmonids in the North Atlantic causing large losses to the industry. Still the blood feeding copepod parasite, Lepeophtheirus salmonis, remains the major challenge for the industry. Histological examinations of this parasite have revealed the presence of several virus-like particles including some with morphologies similar to rhabdoviruses. This study is the first description of the genome and target tissues of two new species of rhabdoviruses associated with pathology in the salmon louse. Salmon lice were collected at different Atlantic salmon (Salmo salar) farming sites on the west coast of Norway and prepared for histology, transmission electron microscopy and Illumina sequencing of the complete RNA extracted from these lice. The nearly complete genomes, around 11 600 nucleotides encoding the five typical rhabdovirus genes N, P, M, G and L, of two new species were obtained. The genome sequences, the putative protein sequences, and predicted transcription strategies for the two viruses are presented. Phylogenetic analyses of the putative N and L proteins indicated closest similarity to the Sigmavirus/Dimarhabdoviruses cluster, however, the genomes of both new viruses are significantly diverged with no close affinity to any of the existing rhabdovirus genera. In situ hybridization, targeting the N protein genes, showed that the viruses were present in the same glandular tissues as the observed rhabdovirus-like particles. Both viruses were present in all developmental stages of the salmon louse, and associated with necrosis of glandular tissues in adult lice. As the two viruses were present in eggs and free-living planktonic stages of the salmon louse vertical, transmission of the viruses are suggested. The tissues of the lice host, Atlantic salmon, with the exception of skin at the attachment site for the salmon louse chalimi stages, were negative for these two viruses. PMID:25402203

Diversity of the free-living marine and freshwater Copepoda (Crustacea) in Costa Rica: a review

PubMed Central

Morales-Ramírez, Álvaro; Suárez-Morales, Eduardo; Corrales-Ugalde, Marco; Garrote, Octavio Esquivel

2014-01-01

Abstract The studies on marine copepods of Costa Rica started in the 1990’s and focused on the largest coastal-estuarine systems in the country, particularly along the Pacific coast. Diversity is widely variable among these systems: 40 species have been recorded in the Culebra Bay influenced by upwelling, northern Pacific coast, only 12 in the Gulf of Nicoya estuarine system, and 38 in Golfo Dulce, an anoxic basin in the southern Pacific coast of the country. Freshwater environments of Costa Rica are known to harbor a moderate diversity of continental copepods (25 species), which includes 6 calanoids, 17 cyclopoids and only two harpacticoids. Of the +100 freshwater species recorded in Central America, six are known only from Costa Rica, and one appears to be endemic to this country. The freshwater copepod fauna of Costa Rica is clearly the best known in Central America. Overall, six of the 10 orders of Copepoda are reported from Costa Rica. A previous summary by 2001 of the free-living copepod diversity in the country included 80 marine species (67 pelagic, 13 benthic). By 2009, the number of marine species increased to 209: 164 from the Pacific (49% of the copepod fauna from the Eastern Tropical Pacific) and 45 from the Caribbean coast (8% of species known from the Caribbean Basin). Both the Caribbean and Pacific species lists are growing. Additional collections of copepods at Cocos Island, an oceanic island 530 km away of the Pacific coast, have revealed many new records, including five new marine species from Costa Rica. Currently, the known diversity of marine copepods of Costa Rica is still in development and represents up to 52.6% of the total marine microcrustaceans recorded in the country. Future sampling and taxonomic efforts in the marine habitats should emphasize oceanic environments including deep waters but also littoral communities. Several Costa Rican records of freshwater copepods are likely to represent undescribed species. Also, the

Diversity of the free-living marine and freshwater Copepoda (Crustacea) in Costa Rica: a review.

PubMed

Morales-Ramírez, Álvaro; Suárez-Morales, Eduardo; Corrales-Ugalde, Marco; Garrote, Octavio Esquivel

2014-01-01

The studies on marine copepods of Costa Rica started in the 1990's and focused on the largest coastal-estuarine systems in the country, particularly along the Pacific coast. Diversity is widely variable among these systems: 40 species have been recorded in the Culebra Bay influenced by upwelling, northern Pacific coast, only 12 in the Gulf of Nicoya estuarine system, and 38 in Golfo Dulce, an anoxic basin in the southern Pacific coast of the country. Freshwater environments of Costa Rica are known to harbor a moderate diversity of continental copepods (25 species), which includes 6 calanoids, 17 cyclopoids and only two harpacticoids. Of the +100 freshwater species recorded in Central America, six are known only from Costa Rica, and one appears to be endemic to this country. The freshwater copepod fauna of Costa Rica is clearly the best known in Central America. Overall, six of the 10 orders of Copepoda are reported from Costa Rica. A previous summary by 2001 of the free-living copepod diversity in the country included 80 marine species (67 pelagic, 13 benthic). By 2009, the number of marine species increased to 209: 164 from the Pacific (49% of the copepod fauna from the Eastern Tropical Pacific) and 45 from the Caribbean coast (8% of species known from the Caribbean Basin). Both the Caribbean and Pacific species lists are growing. Additional collections of copepods at Cocos Island, an oceanic island 530 km away of the Pacific coast, have revealed many new records, including five new marine species from Costa Rica. Currently, the known diversity of marine copepods of Costa Rica is still in development and represents up to 52.6% of the total marine microcrustaceans recorded in the country. Future sampling and taxonomic efforts in the marine habitats should emphasize oceanic environments including deep waters but also littoral communities. Several Costa Rican records of freshwater copepods are likely to represent undescribed species. Also, the biogeographic relevance

Effects of host migration, diversity and aquaculture on sea lice threats to Pacific salmon populations.

PubMed

Krkosek, Martin; Gottesfeld, Allen; Proctor, Bart; Rolston, Dave; Carr-Harris, Charmaine; Lewis, Mark A

2007-12-22

Animal migrations can affect disease dynamics. One consequence of migration common to marine fish and invertebrates is migratory allopatry-a period of spatial separation between adult and juvenile hosts, which is caused by host migration and which prevents parasite transmission from adult to juvenile hosts. We studied this characteristic for sea lice (Lepeophtheirus salmonis and Caligus clemensi) and pink salmon (Oncorhynchus gorbuscha) from one of the Canada's largest salmon stocks. Migratory allopatry protects juvenile salmon from L. salmonis for two to three months of early marine life (2-3% prevalence). In contrast, host diversity facilitates access for C. clemensi to juvenile salmon (8-20% prevalence) but infections appear ephemeral. Aquaculture can augment host abundance and diversity and increase parasite exposure of wild juvenile fish. An empirically parametrized model shows high sensitivity of salmon populations to increased L. salmonis exposure, predicting population collapse at one to five motile L. salmonis per juvenile pink salmon. These results characterize parasite threats of salmon aquaculture to wild salmon populations and show how host migration and diversity are important factors affecting parasite transmission in the oceans.

EMBRYONIC DEVELOPMENT AND A QUANTITATIVE MODEL OF PROGRAMMED DNA ELIMINATION IN MESOCYCLOPS EDAX (S. A. FORBES, 1891) (COPEPODA: CYCLOPOIDA)

PubMed Central

Clower, Michelle K.; Holub, Ashton S.; Smith, Rebecca T.; Wyngaard, Grace A.

2016-01-01

The highly programmed fragmentation of chromosomes and elimination of large amounts of nuclear DNA from the presomatic cell lineages (i.e., chromatin diminution), occurs in the embryos of the freshwater zooplankton Mesocyclops edax (S. A. Forbes, 1891) (Crustacea: Copepoda). The somatic genome is reorganized and reduced to a size five times smaller even though the germline genome remains intact. We present the first comprehensive, quantitative model of DNA content throughout embryogenesis in a copepod that possesses embryonic DNA elimination. We used densitometric image analysis to measure the DNA content of polar bodies, germline and somatic nuclei, and excised DNA “droplets.” We report: 1) variable DNA contents of polar bodies, some of which do not contain the amount corresponding to the haploid germline genome size; 2) presence of pronuclei in newly laid embryo sacs; 3) gonomeric chromosomes in the second to fourth cleavage divisions and in the primordial germ cell and primordial endoderm cell during the fifth cleavage division; 4) timing of early embryonic cell stages, elimination of DNA, and divisions of the primordial germ cell and primordial endoderm cell at 22°C; and 5) persistence of a portion of the excised DNA “droplets” throughout embryogenesis. DNA elimination is a trait that spans multiple embryonic stages and a knowledge of the timing and variability of the associated cytological events with DNA elimination will promote the study of the molecular mechanisms involved in this trait. We propose the “genome yolk hypothesis” as a functional explanation for the persistence of the eliminated DNA that might serve as a resource during postdiminution cleavage divisions. PMID:27857452

Acanthocephalan parasites of slimy sculpin, Cottus cognatus, and Ninespine Stickleback, Pungitius pungitius, from Lake Michigan, U.S.A.

USGS Publications Warehouse

Muzzall, Patrick M.; Lima, Michael; Gentile, Alex; Gunn, Jacob; Jones, Amanda; Morrison, Jamie; French, John R. P.

2012-01-01

In total, 288 slimy sculpins, Cottus cognatus, were collected in September 2003 from 6 Lake Michigan, U.S.A., ports, along with 220 ninespine sticklebacks, Pungitius pungitius, from 3 ports. The ports included Waukegan, Illinois; Port Washington (PW) and Sturgeon Bay (SB), Wisconsin; and Manistique (MS), Frankfort (FF), Ludington (LD), and Saugatuck, Michigan. Echinorhynchus salmonis infected sculpins from 6 ports, Acanthocephalus dirus infected sculpins from 4 ports, and Neoechinorhynchus pungitius infected sculpins from 3 ports. Echinorhynchus salmonis infected significantly more sculpins at PW and at FF than at MS and LD. There were several significant differences in the intensities and abundances of E. salmonis among ports. Acanthocephalus dirus significantly infected more sculpins and had significantly higher abundances at FF than at PW, MS, and LD. Echinorhynchus salmonis, A. dirus, and N. pungitius infected sticklebacks from SB, MS, and FF. Neoechinorhynchus pungitius significantly infected more sculpins and more sticklebacks, and it had significantly higher abundances at MS than at FF. Neoechinorhynchus pungitius was the most common acanthocephalan in C. cognatus and P. pungitius at MS. These acanthocephalan species infecting C. cognatus and P. pungitius corresponded in their occurrence to those organisms that serve as their intermediate hosts found in the stomachs of both fish species. Potential changes in the diet of C. cognatus played a role in significant differences found for E. salmonis and N. pungitius at MS. One of these acanthocephalan species was always the most numerous helminth species found in the digestive tracts of P. pungitius and C. cognatus from these Lake Michigan ports.

A common-garden experiment to quantify evolutionary processes in copepods: the case of emamectin benzoate resistance in the parasitic sea louse Lepeophtheirus salmonis.

PubMed

Ljungfeldt, Lina Eva Robin; Espedal, Per Gunnar; Nilsen, Frank; Skern-Mauritzen, Mette; Glover, Kevin Alan

2014-05-19

The development of pesticide resistance represents a global challenge to food production. Specifically for the Atlantic salmon aquaculture industry, parasitic sea lice and their developing resistance to delousing chemicals is challenging production. In this study, seventeen full sibling families, established from three strains of Lepeophtheirus salmonis displaying differing backgrounds in emamectin benzoate (EB) tolerance were produced and quantitatively compared under a common-garden experimental design. Lice surviving to the preadult stage were then exposed to EB and finally identified through the application of DNA parentage testing. With the exception of two families (19 and 29%), survival from the infectious copepod to preadult stage was very similar among families (40-50%). In contrast, very large differences in survival following EB exposure were observed among the families (7.9-74%). Family survival post EB exposure was consistent with the EB tolerance characteristics of the strains from which they were established and no negative effect on infection success were detected in association with increased EB tolerance. Two of the lice families that displayed reduced sensitivity to EB were established from a commercial farm that had previously used this chemical. This demonstrates that resistant alleles were present on this farm even though the farm had not reported treatment failure. To our knowledge, this represents the first study where families of any multi-cellular parasite have been established and compared in performance under communal rearing conditions in a common-garden experiment. The system performed in a predictable manner and permitted, for the first time, elucidation of quantitative traits among sea lice families. While this experiment concentrated on, and provided a unique insight into EB sensitivity among lice families, the experimental design represents a novel methodology to experimentally address both resistance development and other

A common-garden experiment to quantify evolutionary processes in copepods: the case of emamectin benzoate resistance in the parasitic sea louse Lepeophtheirus salmonis

PubMed Central

2014-01-01

Background The development of pesticide resistance represents a global challenge to food production. Specifically for the Atlantic salmon aquaculture industry, parasitic sea lice and their developing resistance to delousing chemicals is challenging production. In this study, seventeen full sibling families, established from three strains of Lepeophtheirus salmonis displaying differing backgrounds in emamectin benzoate (EB) tolerance were produced and quantitatively compared under a common-garden experimental design. Lice surviving to the preadult stage were then exposed to EB and finally identified through the application of DNA parentage testing. Results With the exception of two families (19 and 29%), survival from the infectious copepod to preadult stage was very similar among families (40-50%). In contrast, very large differences in survival following EB exposure were observed among the families (7.9-74%). Family survival post EB exposure was consistent with the EB tolerance characteristics of the strains from which they were established and no negative effect on infection success were detected in association with increased EB tolerance. Two of the lice families that displayed reduced sensitivity to EB were established from a commercial farm that had previously used this chemical. This demonstrates that resistant alleles were present on this farm even though the farm had not reported treatment failure. Conclusions To our knowledge, this represents the first study where families of any multi-cellular parasite have been established and compared in performance under communal rearing conditions in a common-garden experiment. The system performed in a predictable manner and permitted, for the first time, elucidation of quantitative traits among sea lice families. While this experiment concentrated on, and provided a unique insight into EB sensitivity among lice families, the experimental design represents a novel methodology to experimentally address both resistance

Harpacticoida (Crustacea, Copepoda) across a longitudinal transect of the Vema Fracture Zone and along a depth gradient in the Puerto Rico trench

NASA Astrophysics Data System (ADS)

Schmidt, Christina; Lins, Lidia; Brandt, Angelika

2018-02-01

The aim of this study was the investigation of abundance, composition and biodiversity of benthic deep-sea Harpacticoida (Crustacea, Copepoda) in the Vema Fracture Zone (VFZ) and Puerto Rico trench. The study revealed a clear East-West gradient in total abundance of Harpacticoida with a westward decrease in abundances in the VFZ and significant differences in the community composition in the Eastern (East Vema) and Western Atlantic basin (West Vema) on family and genus level. The Puerto Rico trench and its upper slope did not only differ in abundance, but were distinct with respect to community composition on family and genus level. Thus, the upper slope might be considered as an ecotone, a transition zone where a rapid distinction of species composition occurs. In our study fiarea, 837 adult harpacticoid specimens could be assigned to 16 families and 1 subfamily. The most abundant families found were Ameiridae Boeck, 1865, Pseudotachidiidae Lang, 1936 and Ectinosomatidae Sars, 1903. Genera and species were investigated within selected families (Argestidae Por, 1986, Cletodidae T. Scott, 1905, Canthocamptidae Brady, 1880 and Zosimeidae Seifried, 2003) where 11 genera, and 73 species could be discriminated. Within the selected families, the genera Zosime Boeck, 1873 and Mesocletodes Sars, 1909 were dominant. In the study area, a high number of singletons was detected, which might be endemic to the respective region. Furthermore, a low total number of species in the trench was observed which was attributed to frequent disturbances in the dynamic environment of the Puerto Rico trench (e.g. turbidites or seismic activity) and high adaptability of specialists and opportunists to these disturbances.

Calomel versus carbarsone

USGS Publications Warehouse

Fish, F.F.; McKernan, D.L.

1940-01-01

Octomitus salmonis was introduced to fish culture during the early twenties. This easily found and widely distributed parasite, once recognized, was soon held responsible for practically every ailment noted in trout hatcheries at that time. Such a reputation was doubtless deserved in some instances, but unquestionably many losses ascribed to Octomitus salmonis actually resulted from such troubles as bacterial gill disease, which was then unknown, or from less easily found parasites such as Costia necatrlx. As might be expected, the pendulum of opinion gradually swung to the other extreme.

Effect of temperature and salinity on egg hatching and description of the life cycle of Lernanthropus latis (Copepoda: Lernanthropidae) infecting barramundi, Lates calcarifer.

PubMed

Brazenor, Alexander K; Hutson, Kate S

2013-10-01

The parasite Lernanthropus latis (Copepoda: Lernanthropidae) is a major threat to the sustained mariculture of barramundi, Lates calcarifer (Perciformes: Latidae). We investigated the effect of water temperature and salinity on egg hatching success of L. latis and describe the life cycle for the first time. Wild and sea-caged L. calcarifer examined in tropical north Australia exhibited similar parasite prevalence (range: 80-100%) and mean parasite intensity (range: 3-6), whereas land-based maricultured fish were not infected. Hatching success and time to first and last hatch was determined for a range of water temperature (22, 30, 32 and 34°C) and salinity (0, 11, 22, 35 and 40‰) combinations representing current and predicted climate conditions. There was a significant interaction between water temperature and salinity on the hatching success of L. latis nauplii. Eggs hatched in all temperature treatments, with the greatest hatching success at 30°C and 32°C (98 and 92% success, respectively) in 35‰. Hatching did not occur at 0‰ and was severely reduced at 11‰ (1.6% success). Hatching began within 6h at all water temperatures with >95% of eggs hatched within 30h at 30, 32 and 34°C and within 60h at 22°C. Adult parasites differed from the original description by the presence of the parabasal flagellum, small setae on the legs and caudal rami and minor incongruences regarding morphological measurements. The life cycle of L. latis includes three free living stages and five parasitic stages. Although L. latis exhibits broad environmental tolerance, freshwater can be used as an effective management strategy to break the life cycle in aquaculture. Copyright © 2013 Elsevier Ireland Ltd. All rights reserved.

First records of parasitic copepods (Crustacea, Siphonostomatoida) from marine fishes in Korea.

PubMed

Venmathi Maran, B A; Soh, H Y; Hwang, U W; Chang, C Y; Myoung, J G

2015-06-01

The knowledge of the biodiversity of parasitic copepods in South Korea is increasing. Interestingly we report here, some parasitic copepods considered as the first record of findings from Korea. Nine species of parasitic copepods (Siphonostomatoida) including six genera of three different families [Caligidae (7), Lernaeopodidae (1), Lernanthropidae (1)] were recovered from eight species of wild fishes in Korea: 1) Caligus hoplognathi Yamaguti & Yamasu, 1959 (♀, ♂) from the body surface of barred knifejaw Oplegnathus fasciatus (Temminck & Schlegel); 2) Caligus lagocephali Pillai, 1961 (♀) from the gills of panther puffer Takifugu pardalis (Temminck & Schlegel); 3) Euryphorus brachypterus (Gerstaecker, 1853) (♀, ♂) from the opercular cavity of Atlantic bluefin tuna Thunnus thynnus (Linnaeus); 4) Euryphorus nordmanni Milne Edwards, 1840 (♀, ♂) from the opercular cavity of common dolphin fish Coryphaena hippurus Linnaeus; 5) Gloiopotes huttoni (Thomson) (♀, ♂) from the body surface of black marlin Istiompax indica (Cuvier); 6) Lepeophtheirus hapalogenyos Yamaguti & Yamasu, 1959 (♀) from the gill filaments of O. fasciatus; 7) Lepeophtheirus sekii Yamaguti, 1936 (♀, ♂) from the body surface of red seabream Pagrus major (Temminck & Schlegel); 8) Brachiella thynni Cuvier, 1830 (♀) from the body surface of longfin tuna or albacore Thunnus alalunga (Bonnaterre); 9) Lernanthropinus sphyraenae (Yamaguti & Yamasu, 1959) (♀) from the gill filaments of moon fish Mene maculata (Bloch & Schneider). Since the female was already reported in Korea, it is a new record for the male of C. hoplognathi. A checklist for the parasitic copepods of the family Caligidae, Lernaeopodidae and Lernanthropidae of Korea is provided.

Experimental hexamitiasis in juvenile coho salmon (Oncorhynchus kisutch) and steelhead trout (Salmo gairdner)

USGS Publications Warehouse

1965-01-01

An exogenous strain of cultured Hexamita salmonis (Moore) was employed to induce trophic hexamitiasis in otherwise disease-free juveniles of coho salmon (Oncorhynchus kisutch) and steelhead trout (Salmo gairdneri). Mortality and growth were the parameters used to detect the effects of hexamitiasis on the two species. Two levels of each of the three experimental factors under study, Hexamita infection, species of fish, and density of fish, were arranged in a three-way factorial design. Replicate lots involved a total of 1,440 fish held under controlled laboratory conditions.Comparisons of growth and mortality indicate that infection with H. salmonis over a period of 8 weeks is innocuous to coho salmon. Steelhead trout suffered a low, but statistically significant mortality which subsided after the sixth week; growth rate was not affected.

Expression analysis of the Atlantic bluefin tuna (Thunnus thynnus) pro-inflammatory cytokines, IL-1β, TNFα1 and TNFα2 in response to parasites Pseudocycnus appendiculatus (Copepoda) and Didymosulcus katsuwonicola (Digenea).

PubMed

Pleić, Ivana Lepen; Bušelić, Ivana; Trumbić, Željka; Bočina, Ivana; Šprung, Matilda; Mladineo, Ivona

2015-08-01

Pro-inflammatory cytokines play an important role in teleost defence against numerous types of pathogens, therefore are often used as biomarkers during various infections. In order to evaluate Atlantic bluefin tuna IL-1β, TNFα1 and TNFα2 induction by PAMPs, we quantified their expression during in vitro stimulation of peripheral blood leukocytes by LPS and Poly I:C. Furthermore, their role in acute and chronic parasitic infection was examined during natural infection of Pseudocycnus appendiculatus (Copepoda) and Didymosulcus katsuwonicola (Digenea), as well as during leukocyte exposure to total protein extracts isolated from two parasite species. Induction of ABT IL-1β and TNFα2 by PAMPs and protein extracts from D. katsuwonicola and P. appendiculatus, as well as during natural infection with two parasites, suggests these cytokines play an important role in inflammation, being engaged in controlling parasite infections, in contrast to ABT TNFα1. Cellular innate response to the digenean D. katsuwonicola showed rather chronic character, resulting with parasite encapsulation in connective tissue. Mast cells, eosinophils, goblet cells, and occasional rodlet cells found at the site of infection, along with the induction of TNFα2, suggest the presence of a moderate inflammatory reaction that fails to seriously endanger digenean existence. In contrast, copepod P. appendiculatus, attached to the gill epithelium by clamping, caused direct tissue disruption with undergoing necrotic or apoptotic processes, and extensive proliferation of rodlet and goblet cells. Differential expression patterns of target cytokines in tissue surrounding two parasites and in vitro PBL model suggest that quality and quantity of tuna immune response is conditioned by parasite adaptive mechanisms and pathogenicity. Copyright © 2015 Elsevier Ltd. All rights reserved.

In vivo growth and genomic characterization of rickettsia-like organisms isolated from farmed Chinook salmon (Oncorhynchus tshawytscha) in New Zealand.

PubMed

Gias, E; Brosnahan, C L; Orr, D; Binney, B; Ha, H J; Preece, M A; Jones, B

2018-05-28

A rickettsia-like organism, designated NZ-RLO2, was isolated from Chinook salmon (Oncorhynchus tshawytscha) farmed in the South Island, New Zealand. In vivo growth showed NZ-RLO2 was able to grow in CHSE-214, EPC, BHK-21, C6/36 and Sf21 cell lines, while Piscirickettsia salmonis LF-89 T grew in all but BHK-21 and Sf21. NZ-RLO2 grew optimally in EPC at 15°C, CHSE-214 and EPC at 18°C. The growth of LF-89 T was optimal at 15°C, 18°C and 22°C in CHSE-24, but appeared less efficient in EPC cells at all temperatures. Pan-genome comparison of predicted proteomes shows that available Chilean strains of P. salmonis grouped into two clusters (p-value = 94%). NZ-RLO2 was genetically different from previously described NZ-RLO1, and both strains grouped separately from the Chilean strains in one of the two clusters (p-value = 88%), but were closely related to each other. TaqMan and Sybr Green real-time PCR targeting RNA polymerase (rpoB) and DNA primase (dnaG), respectively, were developed to detect NZ-RLO2. This study indicates that the New Zealand strains showed a closer genetic relationship to one of the Chilean P. salmonis clusters; however, more Piscirickettsia genomes from wider geographical regions and diverse hosts are needed to better understand the classification within this genus. © 2018 John Wiley & Sons Ltd.

The Impact of Feedback Frequency on Learning and Task Performance: Challenging the "More Is Better" Assumption

ERIC Educational Resources Information Center

Lam, Chak Fu; DeRue, D. Scott; Karam, Elizabeth P.; Hollenbeck, John R.

2011-01-01

Previous research on feedback frequency suggests that more frequent feedback improves learning and task performance (Salmoni, Schmidt, & Walter, 1984). Drawing from resource allocation theory (Kanfer & Ackerman, 1989), we challenge the "more is better" assumption and propose that frequent feedback can overwhelm an individual's cognitive resource…

The infection dynamicsof sea lice on sentinel Atlantic salmon in Cobscook Bay, ME

USDA-ARS?s Scientific Manuscript database

This study set out to understand the infection dynamics of sea lice, Lepeophtheirus salmonis an ectoparasite of Atlantic salmon in Cobscook Bay, Maine. Spatial and temporal patterns of parasite settlement were investigated between June 2013 and June 2015. The infective pressure was assessed on a mon...

Sea lice infestations on farmed Atlantic salmon in Scotland and the use of ectoparasitic treatments.

PubMed

Revie, C W; Gettinby, G; Treasurer, J W; Grant, A N; Reid, S W J

A recently compiled national database on sea lice infestations on farmed Atlantic salmon, contains detailed records for the period 1996 to 2000 from over 30 commercial sites on the west coast of Scotland. The data indicate that the two prevalent species of lice, Lepeophtheirus salmonis and Caligus elongatus, have different trends in abundance and distinctive seasonal patterns of infestation on farmed salmon. For the economically important species L salmonis, its abundance on fish varies with the time of the production cycle, the time of year and the particular year. Weekly fluctuations in sea lice counts indicate that treatment can be very effective in controlling infestations but that the counts recover rapidly and regular treatments are necessary to ensure control. A comparison of sites using medium or large numbers of treatments suggests that they do not reduce sea lice infestations to the same levels. There is also evidence that sites using treatments based on different chemical constituents had significantly different levels of infestation.

Comparisons between POC and zooplankton swimmer flux from sediment traps in the subarctic and subtropical North Pacific

NASA Astrophysics Data System (ADS)

Yokoi, Naoya; Abe, Yoshiyuki; Kitamura, Minoru; Honda, Makio C.; Yamaguchi, Atsushi

2018-03-01

Seasonal changes in zooplankton swimmer (ZS) abundance, biomass and community structure were evaluated based on samples collected by moored sediment traps at a depth of 200 m in the subarctic (SA) and subtropical (ST) western North Pacific. Based on these samples, we made comparisons on two topics: 1) latitudinal (subarctic vs. subtropical) changes in ZS abundance, biomass and community and 2) quantitative differences between the ZS and particle organic carbon (POC) fluxes based on data from moored or drifting sediment traps. The results showed that the ZS flux was greater in the SA (annual mean: 311 ind. m-2 day-1 or 258 mg C m-2 day-1) than in the ST (135 ind. m-2 day-1 or 38 mg C m-2 day-1). The peak ZS flux was observed from July-August in the SA and from April-May in the ST. The dominant taxa were Copepoda and Chaetognatha in the SA and Ostracoda and Mollusca in the ST. These latitudinal differences are likely related to the dominance of large-sized Copepoda in the SA, regional differences in the timing of the spring phytoplankton bloom, and the magnitude and size structure of primary producers. The percent composition of ZS to the total C flux (= ZS+POC flux) varied by region: 85-95% in the SA and 47-75% in the ST. These differences between the ZS composition and the total C flux are most likely caused by the dominance of large-sized Copepoda (Neocalanus spp. and Eucalanus bungii) in the SA.

Co-infestation of gills by different parasite groups in the mullet, Mugil platanus Günther, 1880 (Osteichthyes, Mugilidae): effects on relative condition factor.

PubMed

Ranzani-Paiva, M J T; Silva-Souza, A T

2004-08-01

This study involved 334 specimens of mullet, Mugil platanus, captured monthly in the estuarine region of Cananéia, São Paulo State, Brazil, from July 1988 to June 1989, and examined for the presence of gill parasites. Parasitological inspections revealed the occurrence of the following groups: Trichodina sp., Monogenoidea, Copepoda, and Hirudinea. Only four mullets were not parasitized. Total weight and total length of all 334 mullet specimens examined were used for adjusting the weight-length relationship curve and calculating the relative condition factor (Kn). The 118 specimens infested with monogenoideans on average had lower weights than expected (Kn < 1.0), and the 81 fish co-infested with Copepoda, Monogenoidea, and Trichodina sp. showed a Kn < 1.0. The other infested and non-infested mullets had a Kn > 1.0. It was possible to infer that gill infestation with monogenoideans alters mullet weight, especially in the presence of co-infestation with Trichodina sp. and copepods.

Structural basis for the fast maturation of Arthropoda green fluorescent protein

PubMed Central

Evdokimov, Artem G; Pokross, Matthew E; Egorov, Nikolay S; Zaraisky, Andrey G; Yampolsky, Ilya V; Merzlyak, Ekaterina M; Shkoporov, Andrey N; Sander, Ian; Lukyanov, Konstantin A; Chudakov, Dmitriy M

2006-01-01

Since the cloning of Aequorea victoria green fluorescent protein (GFP) in 1992, a family of known GFP-like proteins has been growing rapidly. Today, it includes more than a hundred proteins with different spectral characteristics cloned from Cnidaria species. For some of these proteins, crystal structures have been solved, showing diversity in chromophore modifications and conformational states. However, we are still far from a complete understanding of the origin, functions and evolution of the GFP family. Novel proteins of the family were recently cloned from evolutionarily distant marine Copepoda species, phylum Arthropoda, demonstrating an extremely rapid generation of fluorescent signal. Here, we have generated a non-aggregating mutant of Copepoda fluorescent protein and solved its high-resolution crystal structure. It was found that the protein β-barrel contains a pore, leading to the chromophore. Using site-directed mutagenesis, we showed that this feature is critical for the fast maturation of the chromophore. PMID:16936637

Trends in freshwater microcrustaceans studies in Brazil between 1990 and 2014.

PubMed

Silva, W M; Perbiche-Neves, G

2017-01-01

This study presents a review of scientiometric data about freshwater microcrustaceans (Copepoda, Ostracoda, Branchiopoda: Cladocera, Anostraca, Notostraca and Conchostraca) in Brazil from 1990-2014. This review is based on 179 papers published across four databases, using the following keywords in the search: microcrustaceans, Copepoda, Cyclopoida, Calanoida, Harpacticoida, Ergasilidae, Daphniidae, Moinidae, Cladocera, Ostracoda, Conchostraca, zooplankton, reservoir, river, ponds, reservoirs, wetlands, caves, lakes, limnology, ecology, aquatic, taxonomy, systematics, morphology and biogeography. No studies were identified that addressed freshwater microcrustaceans in four (Amapá, Roraima, Alagoas and Espírito Santo) of the 27 Brazilian Federative States. Forty-five percent of the included studies were concentrated within three of the most populous states (São Paulo, Minas Gerais and Paraná), which also have a long tradition of limnological study. The included studies mostly addressed reservoirs for hydropower generation (22%), multiple environments (22%), rivers (14%) and small artificial reservoirs (11%). Pools, ponds, small lakes, wetlands and phytothelma were not widely studied. Cladocera (48%) and Copepoda (48%) were the most studied groups. No studies were identified that addressed Notostraca, Anostraca or Conchostraca. The sharp increase in the number of published freshwater studies after 2000 is likely a result of increased internet facilities and the implementation of the Scielo platform. Ecology was most frequently the study focus (~50%), followed by taxonomy. Three journals (two Brazilian and one international) accounted for the publication of 44% of the Brazilian studies on microcrustaceans. We expect the frequency of studies employing newer technologies to increase in the coming years. Based on our findings, we propose that future studies should focus on the least well-studied states and should integrate biogeography and systematic approaches

Deltamethrin resistance in the sea louse Caligus rogercresseyi (Boxhall and Bravo) in Chile: bioassay results and usage data for antiparasitic agents with references to Norwegian conditions.

PubMed

Helgesen, K O; Bravo, S; Sevatdal, S; Mendoza, J; Horsberg, T E

2014-10-01

The sea louse Caligus rogercresseyi is a major threat to Chilean salmonid farming. Pyrethroids have been used for anticaligus treatments since 2007, but have shown reduced effect, most likely due to resistance development. Pyrethroid resistance is also a known problem in Lepeophtheirus salmonis in the Northern Hemisphere. This study describes the development of deltamethrin resistance in C. rogercresseyi based on bioassays and usage data for pyrethroids in Chilean aquaculture. These results were compared to bioassays from L. salmonis from Norway and to Norwegian usage data. Available deltamethrin bioassay results from 2007 and 2008, as well as bioassays from Norway, were collected and remodelled. Bioassays were performed on field-collected sea lice in region X in Chile in 2012 and 2013. Bioassays from 2007 were performed prior to the introduction of pyrethroids to the Chilean market. Both the results from 2008 and 2012 showed an increased resistance. Increased pyrethroid resistance was also indicated by the increased use of pyrethroids in Chilean aquaculture compared with the production of salmonids. A similar trend was seen in the Norwegian usage data. The bioassay results from Chile from 2012 and 2013 also indicated a difference in the susceptibility to deltamethrin between male and female caligus. © 2014 John Wiley & Sons Ltd.

Leading from the Center: General Stanley McChrystal’s Quest to Establish a Multinational Counterinsurgent Force in ISAF - A Case Study in Operational Command

DTIC Science & Technology

2011-03-29

Department of the Army, March 26, 2010), 1-5. 23 Paula Holmes-Eber and Barak Salmoni, Operational Culture for the Warfighter (Quantico: Marine Corps...1518,554033,00.html (accessed March 28, 2011). 40 In considering the diverse make-up of ISAF, this is an important point. Peter Rosen contends "military...organizations are shaped by internal conditions of their country of origin." See: Peter Rosen , "Military Effectiveness: Why Society Matters

Sea lice population and sex differences in P-glycoprotein expression and emamectin benzoate resistance on salmon farms in the Bay of Fundy, New Brunswick, Canada.

PubMed

Igboeli, Okechukwu O; Burka, John F; Fast, Mark D

2014-06-01

Parasitic sea lice are a major challenge for salmon aquaculture. This is especially due to the recent development of resistance to emamectin benzoate (EMB) in the parasite. We investigated: (1) whether EMB treatment success in Grand Manan, Bay of Fundy, NB, Canada can be explained through EMB bioassay and P-glycoprotein (P-gp) mRNA expression studies; (2) if other populations of sea lice not under EMB selective pressure possess similar EMB sensitivity as Grand Manan sea lice populations; and (3) the heritability of EMB resistance in Lepeophtheirus salmonis. EMB bioassay results indicated population, species, sex and temporal differences in EMB EC50 values. RT-qPCR analyses revealed population and sex differences in P-gp mRNA levels, correlating with the bioassay results. Laboratory-reared sea lice maintained their EMB sensitivity status up to the F3 generation. Caligus elongatus, collected from Grand Manan showed more than twofold lower EMB EC50 values compared with L. salmonis collected from the same site. Concurrent exposure to EMB and verapamil yielded no increase in C. elongatus sensitivity to the parasiticide. Sea lice bioassay and P-gp mRNA studies can be used to track EMB resistance and sex differences in EMB sensitivity and P-gp mRNA levels exist in the parasite. © 2013 Society of Chemical Industry.

Coinfection takes its toll: Sea lice override the protective effects of vaccination against a bacterial pathogen in Atlantic salmon.

PubMed

Figueroa, Carolina; Bustos, Paulina; Torrealba, Débora; Dixon, Brian; Soto, Carlos; Conejeros, Pablo; Gallardo, José A

2017-12-19

Vaccination is considered crucial for disease prevention and fish health in the global salmon farming industry. Nevertheless, some aspects, such as the efficacy of vaccines, can be largely circumvented during natural coinfections. Sea lice are ectoparasitic copepods that can occur with a high prevalence in the field, are frequently found in co-infection with other pathogens, and are highly detrimental to fish health. The aim of this case-control study was to evaluate the interaction between the detrimental effects of coinfection and the protective effects of vaccination in fish. We used the interaction between the sea louse Caligus rogercresseyi, the bacterial pathogen Piscirickettsia salmonis, and their host, the Atlantic salmon Salmo salar, as a study model. Our results showed that coinfection decreased the accumulated survival (AS) and specific growth rate (SGR) of vaccinated fish (AS = 5.2 ± 0.6%; SGR = -0.05 ± 0.39%) compared to a single infection of P. salmonis (AS = 42.7 ± 1.3%; SGR = 0.21 ± 0.22%). Concomitantly, the bacterial load and clinical signs of disease were significantly increased in coinfected fish. Coinfection may explain the reduced efficacy of vaccines in sea cages and highlights the need to test fish vaccines in more diverse conditions rather than with a single infection.

Plasmacytoid leukemia of chinook salmon.

PubMed

Kent, M L; Eaton, W D; Casey, J W

1997-04-01

Plasmacytoid leukemia is a common disease of seawater pen-reared chinook salmon (Oncorhynchus tshawytscha) in British Columbia, Canada, but has also been detected in wild salmon, in freshwater-reared salmon in United States, and in salmon from netpens in Chile. The disease can be transmitted under laboratory conditions, and is associated with a retrovirus, the salmon leukemia virus. However, the proliferating plasmablasts are often infected with the microsporean Enterocytozoon salmonis, which may be an important co-factor in the disease.

[Localization of crustaceans--fish parasites and nose capsules as the habitat of the genus Salmincola (Podoplea: Lernaeopodidae) mesoparasites].

PubMed

Pronin, N M; Burdukovskaia, T G

2013-01-01

Copepoda parasitica of Baikal fishes (16 species) is divided into 7 groups according to their localization: parasites of the gill apparatus, gill covers, gill and buccal cavities, nasal fossa, cutaneous covering, and fins. It was proposed to separate nasal fossa parasites as the special ecological group ofmesoparasites. Typical speciemens of the group include crustaceans Salmincola longimanus complex--parasites of grayling and cisco fishes consist of three species (S. longimanus, S. svetlanovi, S. lavaretus) and one subspecies (S. longimanus sibirica).

Feeding habits of the deep-snouted pipefish Syngnathus typhle in a temperate coastal lagoon

NASA Astrophysics Data System (ADS)

Oliveira, Frederico; Erzini, Karim; Gonçalves, Jorge M. S.

2007-03-01

Feeding habits of Syngnathus typhle were determined based on monthly sampling during experimental fishing in a coastal lagoon (Ria Formosa, South Portugal) from April 2001 to May 2002. The gut contents of 856 individuals were analysed and quantified with numerical and gravimetric methods, as well as with some complementary indices and measures (vacuity, fullness and relative importance). In this study, this species fed mainly on Copepoda, Mysidacea, small caridean grass shrimps (Hippolytidae and Palaemonidae) and small fishes (Gobiidae) and to a lesser degree on other small invertebrates. No significant differences were found between the diets of males and females. However, significant differences in the fullness indexes of both sexes were observed during the reproductive period. Significant differences in the diet among seasons were also verified but no seasonal trends were discovered. Snout length showed a linear increase with growth while mouth area and total length displayed an allometric relation. Mouth shape varied between an ellipse and an almost perfect circle. The increase in mouth area and snout length as S. typhle grows contributed to the observed ontogenic diet shift with specimens smaller than 10 cm feeding almost exclusively on Copepoda, medium sized specimens feeding mainly on Hippolytidae and Mysidacea, while larger specimens preyed on Hippolytidae, Palaemonidae and Gobiidae. Prey size generally increased with size of S. typhle.

First Report of Tumor-Like Anomalies on the Copepods and their Seasonality from the Obhur Creek, Jeddah Coast, Central Red Sea

NASA Astrophysics Data System (ADS)

Al-Aidaroos, Ali M.; Mantha, Gopikrishna

2018-06-01

Monthly abundance of the subclass Copepoda was analyzed from the zooplankton samples collected at Obhur Creek, Jeddah, Saudi Arabia during December-2011 till December-2012. Zooplankton samples were collected through surface horizontal tows by a modified WP2 net ( via. mouth diameter 50 cm, length 180 cm, 150 μm mesh size). Order Calanoida dominated the abundance with mean annual average of 75.29%. We observed abnormal protuberances on copepods, known as tumour-like anomalies (TLAs). Calanoida showed more frequent and prominent TLAs on its dorsal surface with highest mean percentage occurring during Jun. 2012 (1.64%). The percentage prevalence of TLAs on the Copepoda was highest during Jun. 2012 (1.36%) and least during Nov. 2012 (0.03%). It is suggested that these TLAs might be caused due to the presence of potentially high levels of toxic substances, which weakens the exoskeleton and thereby making them more susceptible to infections or due to wounds from parasites or might be related to the occurrence of symbiotic tantulocarids or might be due to the radiation stress as a control measure. Whatever the reason, these TLAs have become a serious emerging threat to the aquatic food web. Our investigation is the first of its kind in the coastal waters of the Saudi Red Sea, which needs further investigations in order to elucidate the possible reasons for these abnormalities.

The Impact of Water Table Drawdown and Drying on Subterranean Aquatic Fauna in In-Vitro Experiments

PubMed Central

Stumpp, Christine; Hose, Grant C.

2013-01-01

The abstraction of groundwater is a global phenomenon that directly threatens groundwater ecosystems. Despite the global significance of this issue, the impact of groundwater abstraction and the lowering of groundwater tables on biota is poorly known. The aim of this study is to determine the impacts of groundwater drawdown in unconfined aquifers on the distribution of fauna close to the water table, and the tolerance of groundwater fauna to sediment drying once water levels have declined. A series of column experiments were conducted to investigate the depth distribution of different stygofauna (Syncarida and Copepoda) under saturated conditions and after fast and slow water table declines. Further, the survival of stygofauna under conditions of reduced sediment water content was tested. The distribution and response of stygofauna to water drawdown was taxon specific, but with the common response of some fauna being stranded by water level decline. So too, the survival of stygofauna under different levels of sediment saturation was variable. Syncarida were better able to tolerate drying conditions than the Copepoda, but mortality of all groups increased with decreasing sediment water content. The results of this work provide new understanding of the response of fauna to water table drawdown. Such improved understanding is necessary for sustainable use of groundwater, and allows for targeted strategies to better manage groundwater abstraction and maintain groundwater biodiversity. PMID:24278111

Diversity of the Monstrilloida (Crustacea: Copepoda)

PubMed Central

Suárez-Morales, Eduardo

2011-01-01

Monstrilloid copepods are protelean parasites of different groups of marine benthic invertebrates. Only their first naupliar, preadult, and adult phases are planktonic. Monstrilloids are currently represented by more than 115 nominal species contained in four genera. Its taxonomic knowledge has been hampered by nomenclatural and descriptive problems derived from their peculiar ontogeny and poor definitions of taxa. One of the most important difficulties is that of matching males to females. The only reliable methods to link the sexes of a species are the confirmation of particular apomorphies shared by both sexes, finding both sexes in the same host or as a pre-copulatory male-female pair in the plankton, or by the use of molecular markers. A general overview of the morphology of the group and its life cycle is provided herein. Recently, upgraded descriptive standards have been established and the relevance of redescribing taxa based on type and museum specimens has been demonstrated. The rate of species description per decade has had several peaks between 1840 and 2010: (1971–1980, 1991–2000, 2001–2010), each related to the activity of a few researchers. An analysis of the world distribution of published records of the Monstrilloida revealed that the Northeast Atlantic is the best studied region (45% of all records), followed by the Northwestern Atlantic (17%); the least surveyed areas include regions of the southern hemisphere (less than 3%). The Northeast Atlantic region harbors the highest number of known species (32 nominal species), followed by the Caribbean Sea/Gulf of Mexico (24), the Mediterranean/Black Sea (19), Indonesia-Malaysia-Philippines region (17), Japanese waters (17), and the Brazil-Argentina area (16). Other than these generalized patterns, little can be concluded concerning the biogeography of the group. Many species records are doubtful or improbable, and purportedly cosmopolitan nominal species are being revealed as species complexes yet to be studied. PMID:21853055

USSR and Eastern Europe Scientific Abstracts Biomedical and Behavioral Sciences No. 61

DTIC Science & Technology

1977-01-05

the bacteria-inhibiting circle was only 10 mm in diam and its activity lasted for only 36-48 hr. In the case of lactic acid treatment , the circle...5.00). Table 1. 1/2 UDC 576.8:636.086.6 USSR SIVERS, V. S. and SPRAVTSEV, M. Kh. MICROBIOLOGICAL TREATMENT OF STRAW BY CELLULOSE-AND LIGNIN... treatment of ponds will lead to annihilation of copepoda-filtrates, the fodder objects for valuable commercial fish fry. Action of 0.05-5.0 mg/1

Large-Scale Operations Management Test of Use of the White Amur for Control of Problem Aquatic Plants. Report 1. Baseline Studies. Volume II. The Fish, Mammals, and Waterfowl of Lake Conway, Florida.

DTIC Science & Technology

1979-12-01

and Culicidae. 99. In addition to the sporadic occurrence of minor food items, considerable seasonal variations existed in food habits. Overall, the...included Copepoda, Amphipoda, Hydracarina, and eggs. The remaining 16 food groups were of minor importance in the diet (f bluefin killifish and were...Widgeon 1 Empty Ring-necked duck 8 Seed N.A. 3 American coot 17 Fish 1 1 Hydrilla N.A. 15 Lemna N.A. I Seed N.A. 3 Eleocharis N.A. I Chironomidae 1 1

Epizootics of wild fish induced by farm fish.

PubMed

Krkosek, Martin; Lewis, Mark A; Morton, Alexandra; Frazer, L Neil; Volpe, John P

2006-10-17

The continuing decline of ocean fisheries and rise of global fish consumption has driven aquaculture growth by 10% annually over the last decade. The association of fish farms with disease emergence in sympatric wild fish stocks remains one of the most controversial and unresolved threats aquaculture poses to coastal ecosystems and fisheries. We report a comprehensive analysis of the spread and impact of farm-origin parasites on the survival of wild fish populations. We mathematically coupled extensive data sets of native parasitic sea lice (Lepeophtheirus salmonis) transmission and pathogenicity on migratory wild juvenile pink (Oncorhynchus gorbuscha) and chum (Oncorhynchus keta) salmon. Farm-origin lice induced 9-95% mortality in several sympatric wild juvenile pink and chum salmon populations. The epizootics arise through a mechanism that is new to our understanding of emerging infectious diseases: fish farms undermine a functional role of host migration in protecting juvenile hosts from parasites associated with adult hosts. Although the migratory life cycles of Pacific salmon naturally separate adults from juveniles, fish farms provide L. salmonis novel access to juvenile hosts, in this case raising infection rates for at least the first approximately 2.5 months of the salmon's marine life (approximately 80 km of the migration route). Spatial segregation between juveniles and adults is common among temperate marine fishes, and as aquaculture continues its rapid growth, this disease mechanism may challenge the sustainability of coastal ecosystems and economies.

Comparative genome analysis of two Streptococcus phocae subspecies provides novel insights into pathogenicity.

PubMed

Bethke, J; Avendaño-Herrera, R

2017-02-01

Streptococcus phocae is a beta-hemolytic, Gram-positive bacterium that was first isolated in Norway from clinical specimens of harbor seal (Phoca vitulina) affected by pneumonia or respiratory infection, and in 2005, this bacterium was identified from disease outbreaks at an Atlantic salmon farm. A recent comparative polyphasic study reclassified Streptococcus phocae as subsp. phocae and subsp. salmonis, and there are currently two S. phocae NCBI sequencing projects for the type strains ATCC 51973 T and C-4 T . The present study compared these genome sequences to determine shared properties between the pathogenic mammalian and fish S. phocae subspecies. Both subspecies presented genomic islands, prophages, CRISPRs, and multiple gene activator and RofA regulator regions that could play key roles in the pathogenesis of streptococcal species. Likewise, proteins possibly influencing immune system evasion and virulence strategies were identified in both genomes, including Streptokinases, Streptolysin S, IgG endopeptidase, Fibronectin binding proteins, Daunorubicin, and Penicillin resistance proteins. Comparative differences in phage, non-phage, and genomic island sequences may form the genetic basis for the virulence, pathogenicity, and ability of S. phocae subsp. salmonis to infect and cause disease in Atlantic salmon, in contrast to S. phocae subsp. phocae. This comparative genomic study between two S. phocae subsp. provides novel insights into virulence factors and pathogenicity, offering important information that will facilitate the development of preventive and treatment measures against this pathogen. Copyright © 2016 Elsevier B.V. All rights reserved.

Potential retention effect at fish farms boosts zooplankton abundance

NASA Astrophysics Data System (ADS)

Fernandez-Jover, D.; Toledo-Guedes, K.; Valero-Rodríguez, J. M.; Fernandez-Gonzalez, V.; Sanchez-Jerez, P.

2016-11-01

Coastal aquaculture activities influence wild macrofauna in natural environments due to the introduction of artificial structures, such as floating cages, that provide structural complexity in the pelagic system. This alters the abundance and distribution of the affected species and also their feeding behaviour and diet. Despite this, the effects of coastal aquaculture on zooplankton assemblages and the potential changes in their abundance and distribution remain largely unstudied. Traditional plankton sampling hauls between the farm mooring systems entail some practical difficulties. As an alternative, light traps were deployed at 2 farms in the SW Mediterranean during a whole warm season. Total zooplankton capture by traps at farms was higher than at control locations on every sampling night. It ranged from 3 to 10 times higher for the taxonomic groups: bivalvia, cladocera, cumacea, fish early-life-stages, gastropoda, polychaeta and tanaidacea; 10-20 times higher for amphipoda, chaetognatha, isopoda, mysidacea and ostracoda, and 22 times higher for copepoda and the crustacean juvenile stages zoea and megalopa. Permutational analysis showed significant differences for the most abundant zooplankton groups (copepoda, crustacean larvae, chaetognatha, cladocera, mysidacea and polychaeta). This marked incremental increase in zooplankton taxa at farms was consistent, irrespective of the changing environmental variables registered every night. Reasons for the greater abundance of zooplankton at farms are discussed, although results suggest a retention effect caused by cage structures rather than active attraction through physical or chemical cues.

Zur Biologie von Paramphiascella fulvofasciata (Copepoda, Harpacticoida)

NASA Astrophysics Data System (ADS)

Dahms, Hans-Uwe

1986-09-01

The benthic harpacticoid copepod Paramphiascella fulvofasciata Rosenfield & Coull was collected from holdfasts of Laminaria hyperborea from a subtidal area of Helgoland (North Sea). All developmental stages of P. fulvofasciata are raptorial feeders. The feeding of the nauplii is advanced by a marginal setule-crest of the labrum which prevents food-particles from being swept away. The oral appendages of the copepodites circumscribe a frustal space ventral to the mouth which facilitates uptake of food-particles. The nauplii are not able to swim and perform stalking movements with their antennal endopodites. Good swimming ability as well as digging-in-behaviour and negative phototaxis of the copepodites indicate epi- as well as inbenthic mode of life. Several life-cycle characters are described. Precopula lasts ca. one day. The mean egg-number is 27, and mean egg-diameter is 87 × 75 µm. The number of nauplii per egg (double)-sac amounts to 25 30. Developmental time at 19°C is 6 9 days (nauplii) and 20 24 days (copepodites). The whole developmental period lasts 28 days. The maximal lifespan in the laboratory is 193 days. Sex-ratio is almost balanced. Females produce egg-sacs more than 3.5 times during their life period. Seasonal effects on reproductive activity have not been detected in laboratory cultures.

Reduced growth in wild juvenile sockeye salmon Oncorhynchus nerka infected with sea lice.

PubMed

Godwin, S C; Dill, L M; Krkošek, M; Price, M H H; Reynolds, J D

2017-07-01

Daily growth rings were examined in the otoliths of wild juvenile sockeye salmon Oncorhynchus nerka to determine whether infection by ectoparasitic sea lice Caligus clemensi and Lepeophtheirus salmonis was associated with reduced host body growth, an important determinant of survival. Over 98% of the sea lice proved to be C. clemensi and the fish that were highly infected grew more slowly than uninfected individuals. Larger fish also grew faster than smaller fish. Finally, there was evidence of an interaction between body size and infection status, indicating the potential for parasite-mediated growth divergence. © 2017 The Fisheries Society of the British Isles.

[Parasite fauna of the European river lamprey Lampetra fluviatilis (L.) from Lake Onega].

PubMed

Evseeva, N V

2007-01-01

Data on the parasite fauna of the adult European river lamprey Lampetra fluviatilis (L.) from Lake Onega are reported. Ten parasite species are found, including trematodes Diplostomum petromyzifluviatilis and D. spathaceum (metacercariae), cestode Proteocephalus longicollis, nematodes Cucullanus truttae and Raphidascaris acus, acanthocephalan Echinorhynchus salmonis, ectoparasitic infusoria Chilodonella hexastica, Trichodina tenuidens, and Trichodinella epizootica, and fungus Saprolegnia parasitica. Three species are found to be dominate, namely D. petromyzifluviatilis, Cucullanus truttae, and P. longicollis. Comparative analysis of the parasite faunas of the lampreys from other basins is carried out. Some similarity in the parasite faunas of lampreys and salmonids is discovered.

Modeling the Transmission of Piscirickettsia salmonis in Farmed Salmon

NASA Astrophysics Data System (ADS)

Cisternas, Jaime; Moreno, Adolfo

2007-05-01

Farming Atlantic salmon is an economic activity of growing relevance in the southern regions of Chile. The need to increase efficiency and reach production goals, as well as restrictions on the use of water resources, had led in recent years to certain practices that proved prone to bacterial infections among the fish. Our study focuses on the impact of rickettsial bacteria in farmed salmon, and the possibility of controlling its incidence once it is established along the salmon life cicle. We used compartmental models to separate fish in their maturation stages and health status. The mathematical analysis will involve differential equations with and without delays, and linear stability principles. Our goal was to build a simple model that explains the basic mechanisms at work and provides predictions on the outcome of different control strategies.

Carotenoid metabolic profiling and transcriptome-genome mining reveal functional equivalence among blue-pigmented copepods and appendicularia.

PubMed

Mojib, Nazia; Amad, Maan; Thimma, Manjula; Aldanondo, Naroa; Kumaran, Mande; Irigoien, Xabier

2014-06-01

The tropical oligotrophic oceanic areas are characterized by high water transparency and annual solar radiation. Under these conditions, a large number of phylogenetically diverse mesozooplankton species living in the surface waters (neuston) are found to be blue pigmented. In the present study, we focused on understanding the metabolic and genetic basis of the observed blue phenotype functional equivalence between the blue-pigmented organisms from the phylum Arthropoda, subclass Copepoda (Acartia fossae) and the phylum Chordata, class Appendicularia (Oikopleura dioica) in the Red Sea. Previous studies have shown that carotenoid-protein complexes are responsible for blue coloration in crustaceans. Therefore, we performed carotenoid metabolic profiling using both targeted and nontargeted (high-resolution mass spectrometry) approaches in four different blue-pigmented genera of copepods and one blue-pigmented species of appendicularia. Astaxanthin was found to be the principal carotenoid in all the species. The pathway analysis showed that all the species can synthesize astaxanthin from β-carotene, ingested from dietary sources, via 3-hydroxyechinenone, canthaxanthin, zeaxanthin, adonirubin or adonixanthin. Further, using de novo assembled transcriptome of blue A. fossae (subclass Copepoda), we identified highly expressed homologous β-carotene hydroxylase enzymes and putative carotenoid-binding proteins responsible for astaxanthin formation and the blue phenotype. In blue O. dioica (class Appendicularia), corresponding putative genes were identified from the reference genome. Collectively, our data provide molecular evidences for the bioconversion and accumulation of blue astaxanthin-protein complexes underpinning the observed ecological functional equivalence and adaptive convergence among neustonic mesozooplankton. © 2014 The Authors. Molecular Ecology Published by John Wiley & Sons Ltd.

A new species of Psammogammarus (Amphipoda: Melitidae) from Kuchinoerabu Island, Japan, with a note on its feeding habits.

PubMed

Tomikawa, Ko; Kakui, Keiichi; Yamasaki, Hiroshi

2010-07-01

A new melitoid Amphipoda, Psammogammarus mawatarii, is described from Kuchinoerabu Island, Kagoshima Prefecture, Japan. This is the first record of the genus from Asia. The new species is morphologically similar to P. garthi, but differs from the latter in the following features: 1) lateral cephalic lobe of head not strongly produced; 2) head lacking antennal sinus; and 3) posteroventral corner of epimeral plate 3 rounded. Morphology of maxillae 1 and 2, and mandible, and gut contents (harpacticoid Copepoda) of P. mawatarii indicate that the feeding type of the species seems to be, at least facultatively, carnivorous.

Unexpectedly higher metazoan meiofauna abundances in the Kuril-Kamchatka Trench compared to the adjacent abyssal plains

NASA Astrophysics Data System (ADS)

Schmidt, Christina; Martínez Arbizu, Pedro

2015-01-01

We studied meiofauna standing stocks and community structure in the Kuril-Kamchatka Trench and its adjacent abyssal plains in the northwestern Pacific Ocean. In general, the Nematoda were dominant (93%) followed by the Copepoda (4%). Nematode abundances ranged from 87% to 96%; those of copepods from 2% to 7%. The most diverse deployment yielded 17 taxa: Acari, Amphipoda, Annelida, Bivalvia, Coelenterata, Copepoda, Cumacea, Gastrotricha, Isopoda, Kinorhyncha, Loricifera, Nematoda, Ostracoda, Priapulida, Tanaidacea, Tantulocarida, and Tardigrada. Nauplii were also present. Generally, the trench slope and the southernmost deployments had the highest abundances (850-1392 individuals/cm2). The results of non-metric multidimensional scaling indicated that these deployments were similar to each other in meiofauna community structure. The southernmost deployments were located in a zone of higher particulate organic carbon (POC) flux (g Corg m-2 yr-1), whereas the trench slope should have low POC flux due to depth attenuation. Also, POC and abundance were significantly correlated in the abyssal plains. This correlation may explain the higher abundances at the southernmost deployments. Lateral transport was also assumed to explain high meiofauna abundances on the trench slope. Abundances were generally higher than expected from model results. ANOSIM revealed significant differences between the trench slope and the northern abyssal plains, between the central abyssal plains and the trench slope, between the trench slope and the southern abyssal plains, between the central and the southern abyssal plains, and between the central and northern deployments. The northern and southern abyssal plains did not differ significantly. In addition, a U-test revealed highly significant differences between the trench-slope and abyssal deployments. The taxa inhabited mostly the upper 0-3 cm of the sediment layer (Nematoda 80-90%; Copepoda 88-100%). The trench-slope and abyssal did not differ

Comparative analysis of innate immune responses to Streptococcus phocae strains in Atlantic salmon (Salmo salar) and rainbow trout (Oncorhynchus mykiss).

PubMed

Salazar, Soraya; Oliver, Cristian; Yáñez, Alejandro J; Avendaño-Herrera, Ruben

2016-04-01

Streptococcus phocae subsp. salmonis is a Gram-positive bacterium that causes mortality only in Atlantic salmon (Salmo salar) farmed in Chile, even when this species is co-cultured with rainbow trout (Oncorhynchus mykiss). This susceptibility could be determined by innate immune response components and their responses to bacterial infection. This fish pathogen shares subspecies status with Streptococcus phocae subsp. phocae isolated from seals. The present study compared innate immune system mechanisms in Atlantic salmon and rainbow trout when challenged with different S. phocae, including two isolates from Atlantic salmon (LM-08-Sp and LM-13-Sp) and two from seal (ATCC 51973(T) and P23). Streptococcus phocae growth was evaluated in the mucus and serum of both species, with rainbow trout samples evidencing inhibitory effects. Lysozyme activity supported this observation, with significantly higher (p < 0.01) expression in rainbow trout serum and mucus as compared to Atlantic salmon. No differences were found in phagocytic capacity between fish species when stimulated with ATCC 51973(T) and P23. Against all S. phocae strains, rainbow trout and Atlantic salmon showed up to two-fold increased bactericidal activity, and rainbow trout demonstrated up to three-fold greater reactive oxygen species production in macrophages. In conclusion, the non-specific humoral and cellular barriers of Atlantic salmon were immunologically insufficient against S. phocae subsp. salmonis, thereby facilitating streptococcosis. Moreover, the more robust response of rainbow trout to S. phocae could not be attributed to any specific component of the innate immune system, but was rather the consequence of a combined response by the evaluated components. Copyright © 2016 Elsevier Ltd. All rights reserved.

Cognitive and Temperament Predictors of Executive Ability: Principles for Developing Leadership Capacity

DTIC Science & Technology

1993-05-01

experience essays. Salmoni, A. W ., Schmidt, R. A., & Walter , C. B. (1985). Knowledge of results and motor learning: A review and critical reappraisal...Individuals as producers of their own development: A life-span perspective. New York: Academic Press. Tornow , W . W ., & Pinto, P. R. (1976). The development of...0a S C c -0 0 o 0, olt z - 1:.- 6 is a E 3 0: 060 ac g C : a o , ’ V1 0~ ~ OON g ~ ow aa Ab w .2 c C - too U0b 0b a- - 0 0 C O X WE-- 0 c a0 a = Cc

Changes of concentrations and possibility of accumulation of bisphenol A and alkylphenols, depending on biomass and composition, in zooplankton of the Southern Baltic (Gulf of Gdansk).

PubMed

Staniszewska, Marta; Nehring, Iga; Mudrak-Cegiołka, Stella

2016-06-01

The focus of the present study was to find the relationship between concentrations of bisphenol A (BPA), 4-tert-octylphenol (OP) and 4-nonylphenol (NP) in zooplankton and seasonal changes in the composition and biomass of particular zooplankton taxa in the Gulf of Gdansk (Southern Baltic) in the years 2011-2012. Assays of BPA, OP and NP in water and zooplankton samples were performed using the HPLC/FL system. High mean concentrations of the studied compounds, determined in spring (405.9 (BPA); 25.7 (OP); 111.2 (NP) ng g(-1) dw), can be linked to the high proportion of meroplankton in that season. Rotifera also had an influence on the rise in concentrations of the studied compounds but to a lesser degree, while the lowest concentrations (determined in summer) can be associated with the high participation of Copepoda and Cladocera in zooplankton biomass. It was also observed that juvenile forms can be more susceptible to accumulating endocrine disrupting compounds (EDCs). This is indicated by the positive correlation between BPA concentration in zooplankton and the proportion of Copepoda nauplii biomass in spring (r = 0.90; p < 0.05). In most cases, greater zooplankton biomass accumulated higher concentrations and loads of the studied compounds. With biomass growth (to 123.32 μg m(-3)), the bioconcentration factor also rose (to max 46.1·10(3)), demonstrating that unlike typical hydrophobic compounds the studied EDCs do not become "diluted" in zooplankton biomass. The highest BPA concentrations from all compounds may be connected with anthropogenic sources located in the coastal zone. Copyright © 2016 Elsevier Ltd. All rights reserved.

Northwestward range extension for Diacyclops harryi (Crustacea: Copepoda)

USGS Publications Warehouse

Reid, Janet W.; Hudson, Patrick L.; Bowen, Charles A.

2002-01-01

A recent find of the groundwater-inhabiting copepod crustacean Diacyclops harryi extended the known range of this species far northwestward, to include northern Ohio and the drainage basin of the Laurentian Great Lakes. The species was previously collected in drainages of the Atlantic Slope from New York to North Carolina. Ostracodes tentatively identified as ?Nannocandona n. sp., and amphipods belonging to the subterranean species Bactrurus mucronatus were also found at the Ohio locality.

Carnivory during Ontogeny of the Plagioscion squamosissimus: A Successful Non-Native Fish in a Lentic Environment of the Upper Paraná River Basin

PubMed Central

Neves, Mayara Pereira; Delariva, Rosilene Luciana; Guimarães, Ana Tereza Bittencourt; Sanches, Paulo Vanderlei

2015-01-01

This study evaluated feeding patterns and ontogenetic variations in a non-native fish species (Plagioscion squamosissimus) in an isolated lake in the Upper Paraná River floodplain. Quarterly samplings were performed from April 2005 to February 2006 using plankton nets to capture larvae, seining nets for juveniles, and gill nets and trammel for adults. Stomach contents (n = 378) were examined according to the volumetric method in which the volume of each food item was estimated using graduated test tubes or a glass counting plate. During early development (larval stage), P. squamosissimus consumed mainly Cladocera and Copepoda. Juveniles showed a more diverse diet, including shrimp (Macrobrachium amazonicum), fish, aquatic insects (Trichoptera, Ephemeroptera, Chironomidae and pupae of Diptera) and plants. It was notable the high proportion of cannibalism (23.3%) in this stage. Adults consumed predominantly shrimp and fish. The use of food resources varied significantly between development stages (ANOSIM; r = 0.458; p<0.005), showing changes in food preferences during ontogeny. The Similarity Percentage Analysis (SIMPER) indicated that Cladocera and Copepoda were responsible for the differences observed between the larval stages of pre-flexion, flexion and post-flexion. M. amazonicum and Chironomidae were responsible for the differences between juvenile and larval stages, while M. amazonicum and other fishes caused the differences between adults and other ontogenetic stages. These results are confirmed by the relationship between standard length and developmental periods (ANCOVA; r2 = 0.94; p<0.0001). In general, there were low values of trophic niche breadth. The essentially carnivorous habit from the early stages of P. squamosissimus and the predominant use of M. amazonicum by adults have important roles in feeding patterns of the species, suggesting a major contribution to its success and establishment, especially in lentic environments. PMID:26524336

Occurrence of Ergasilus megaceros Wilson, 1916, in the sea lamprey and other fishes from North America

USGS Publications Warehouse

Muzzall, Patrick M.; Hudson, Patrick L.

2004-01-01

Ergasilus megaceros (Copepoda: Ergasilidae) was recovered from the nasal fossae (lamellae) of the olfactory sac in 1 (1.8%) of 56 sea lampreys, Petromyzon marinus Linne, 1758, collected in May 2002 from the Cheboygan River, Michigan. Although the sea lamprey is a new host record for E. megaceros, this fish species may not be a preferred host because of its low prevalence. Ergasilus megaceros is the second ergasilid species reported from the sea lamprey in North America. This is the third report of an ergasilid species infecting the nasal fossae of fishes in North America, with E. rhinos being the only other species reported from this site.

Feeding ecology of waterfowl wintering on evaporation ponds in California

USGS Publications Warehouse

Euliss, N.H.; Jarvis, R.L.; Gilmer, D.S.

1991-01-01

We examined the feeding ecology of Northern Pintails (Anas acuta), Northern Shovelers (A. clypeata), and Ruddy Ducks (Oxyura jamaicensis) wintering on drainwater evaporation ponds in California from 1982 through 1984. Pintails primarily consumed midges (Chironomidae) (39.3%) and widegeongrass (Ruppia maritima) nutlets (34.6%). Shovelers and Ruddy Ducks consumed 92.5% and 90.1% animal matter, respectively. Water boatmen (Corixidae) (51.6%), rotifers (Rotatoria) (20.4%), and copepods (Copepoda) (15.2%) were the most important Shoveler foods, and midges (49.7%) and water boatmen (36.0%) were the most important foods of Ruddy Ducks. All three species were opportunistic foragers, shifting their diets seasonally to the most abundant foods given their behavioral and morphological attributes.

Declining wild salmon populations in relation to parasites from farm salmon.

PubMed

Krkosek, Martin; Ford, Jennifer S; Morton, Alexandra; Lele, Subhash; Myers, Ransom A; Lewis, Mark A

2007-12-14

Rather than benefiting wild fish, industrial aquaculture may contribute to declines in ocean fisheries and ecosystems. Farm salmon are commonly infected with salmon lice (Lepeophtheirus salmonis), which are native ectoparasitic copepods. We show that recurrent louse infestations of wild juvenile pink salmon (Oncorhynchus gorbuscha), all associated with salmon farms, have depressed wild pink salmon populations and placed them on a trajectory toward rapid local extinction. The louse-induced mortality of pink salmon is commonly over 80% and exceeds previous fishing mortality. If outbreaks continue, then local extinction is certain, and a 99% collapse in pink salmon population abundance is expected in four salmon generations. These results suggest that salmon farms can cause parasite outbreaks that erode the capacity of a coastal ecosystem to support wild salmon populations.

The Australian Monstrilloida (Crustacea: Copepoda) II. Cymbasoma Thompson, 1888.

PubMed

Suárez-Morales, Eduardo; Mckinnon, A David

2016-04-08

Monstrilloid copepods collected during the past two decades from zooplankton surveys in reef and coastal areas of Australia were analyzed. A first contribution included the taxonomic analysis of three genera of the Monstrilloida, Monstrillopsis Sars, 1921, Maemonstrilla Grygier & Ohtsuka, 2008, and the newly described Australomonstrillopsis Suárez-Morales & McKinnon, 2014. In this document a taxonomic analysis of the species belonging to the genus Cymbasoma Thompson, 1888 is provided. A total of 28 species were found, most of them being undescribed. Seventeen species were described based on females only and eight on male specimens while three species were described from both sexes. Males of Australian species of Cymbasoma are distinguished by details of the genital complex, body size and proportions, ornamentation and processes of the cephalic region, number of caudal setae, and the characteristic structure or ornamentation of the genital lappets. Two main groups of males were distinguished on the basis of the number of caudal setae (3 or 4). As for the females, 20 of the 25 new species of Cymbasoma have fifth legs with an unarmed inner lobe and three setae on the outer lobe; one of these species (C. jinigudira sp. nov.) belongs to the C. longispinosum species-group (sensu Üstün et al. 2014). Another group, consisting of five species, has only two setae on the outer (exopodal) lobe. There were no Australian species of Cymbasoma with a single lobe. A species group, named after C. agoense, is proposed to include species sharing a globose body and a female fifth leg with a large endopodal lobe and an outer (exopodal) lobe with two setae. The females of the new species of Cymbasoma from Australia can be distinguished from their known congeners by unique combinations of characters including the type of body ornamentation, body size and shape, antennule armature and proportions, the presence of distinctive features of the legs 1-4, the presence/absence of processes on the genital compound somite, and the presence/absence of a constriction of the anal somite. We report the occurrence of two previously described species, C. agoense Sekiguchi, 1982 from Japan and C. bali Desai & Krishnaswamy, 1962 from India in Australian waters. Considering the addition of the 25 new species here described, the number of nominal species of the genus is now 66. A key to the Australian species of Cymbasoma (males and females) and a map showing their occurrence in Australia are also provided.

Phylogeny of the Paracalanidae Giesbrecht, 1888 (Crustacea: Copepoda: Calanoida).

PubMed

Cornils, Astrid; Blanco-Bercial, Leocadio

2013-12-01

The Paracalanidae are ecologically-important marine planktonic copepods that occur in the epipelagic zone in temperate and tropical waters. They are often the dominant taxon - in terms of biomass and abundance - in continental shelf regions. As primary consumers, they form a vital link in the pelagic food web between primary producers and higher trophic levels. Despite the ecological importance of the taxon, evolutionary and systematic relationships within the family remain largely unknown. A multigene phylogeny including 24 species, including representatives for all seven genera, was determined based on two nuclear genes, small-subunit (18S) ribosomal RNA and Histone 3 (H3) and one mitochondrial gene, cytochrome c oxidase subunit I (COI). The molecular phylogeny was well supported by Maximum likelihood and Bayesian inference analysis; all genera were found to be monophyletic, except for Paracalanus, which was separated into two distinct clades: the Paracalanus aculeatus group and Paracalanus parvus group. The molecular phylogeny also confirmed previous findings that Mecynocera and Calocalanus are genera of the family Paracalanidae. For comparison, a morphological phylogeny was created for 35 paracalanid species based on 54 morphological characters derived from published descriptions. The morphological phylogeny did not resolve all genera as monophyletic and bootstrap support was not strong. Molecular and morphological phylogenies were not congruent in the positioning of Bestiolina and the Paracalanus species groups, possibly due to the lack of sufficient phylogenetically-informative morphological characters. Copyright © 2013 Elsevier Inc. All rights reserved.

Sea Louse Infection of Juvenile Sockeye Salmon in Relation to Marine Salmon Farms on Canada's West Coast

PubMed Central

Price, Michael H. H.; Proboszcz, Stan L.; Routledge, Rick D.; Gottesfeld, Allen S.; Orr, Craig; Reynolds, John D.

2011-01-01

Background Pathogens are growing threats to wildlife. The rapid growth of marine salmon farms over the past two decades has increased host abundance for pathogenic sea lice in coastal waters, and wild juvenile salmon swimming past farms are frequently infected with lice. Here we report the first investigation of the potential role of salmon farms in transmitting sea lice to juvenile sockeye salmon (Oncorhynchus nerka). Methodology/Principal Findings We used genetic analyses to determine the origin of sockeye from Canada's two most important salmon rivers, the Fraser and Skeena; Fraser sockeye migrate through a region with salmon farms, and Skeena sockeye do not. We compared lice levels between Fraser and Skeena juvenile sockeye, and within the salmon farm region we compared lice levels on wild fish either before or after migration past farms. We matched the latter data on wild juveniles with sea lice data concurrently gathered on farms. Fraser River sockeye migrating through a region with salmon farms hosted an order of magnitude more sea lice than Skeena River populations, where there are no farms. Lice abundances on juvenile sockeye in the salmon farm region were substantially higher downstream of farms than upstream of farms for the two common species of lice: Caligus clemensi and Lepeophtheirus salmonis, and changes in their proportions between two years matched changes on the fish farms. Mixed-effects models show that position relative to salmon farms best explained C. clemensi abundance on sockeye, while migration year combined with position relative to salmon farms and temperature was one of two top models to explain L. salmonis abundance. Conclusions/Significance This is the first study to demonstrate a potential role of salmon farms in sea lice transmission to juvenile sockeye salmon during their critical early marine migration. Moreover, it demonstrates a major migration corridor past farms for sockeye that originated in the Fraser River, a complex of

Sea louse infection of juvenile sockeye salmon in relation to marine salmon farms on Canada's west coast.

PubMed

Price, Michael H H; Proboszcz, Stan L; Routledge, Rick D; Gottesfeld, Allen S; Orr, Craig; Reynolds, John D

2011-02-09

Pathogens are growing threats to wildlife. The rapid growth of marine salmon farms over the past two decades has increased host abundance for pathogenic sea lice in coastal waters, and wild juvenile salmon swimming past farms are frequently infected with lice. Here we report the first investigation of the potential role of salmon farms in transmitting sea lice to juvenile sockeye salmon (Oncorhynchus nerka). We used genetic analyses to determine the origin of sockeye from Canada's two most important salmon rivers, the Fraser and Skeena; Fraser sockeye migrate through a region with salmon farms, and Skeena sockeye do not. We compared lice levels between Fraser and Skeena juvenile sockeye, and within the salmon farm region we compared lice levels on wild fish either before or after migration past farms. We matched the latter data on wild juveniles with sea lice data concurrently gathered on farms. Fraser River sockeye migrating through a region with salmon farms hosted an order of magnitude more sea lice than Skeena River populations, where there are no farms. Lice abundances on juvenile sockeye in the salmon farm region were substantially higher downstream of farms than upstream of farms for the two common species of lice: Caligus clemensi and Lepeophtheirus salmonis, and changes in their proportions between two years matched changes on the fish farms. Mixed-effects models show that position relative to salmon farms best explained C. clemensi abundance on sockeye, while migration year combined with position relative to salmon farms and temperature was one of two top models to explain L. salmonis abundance. This is the first study to demonstrate a potential role of salmon farms in sea lice transmission to juvenile sockeye salmon during their critical early marine migration. Moreover, it demonstrates a major migration corridor past farms for sockeye that originated in the Fraser River, a complex of populations that are the subject of conservation concern.

Helminths in an intensively stocked population of lake trout, Salvelinus namaycush, from Lake Huron

USGS Publications Warehouse

Muzzall, Patrick M.; Bowen, Charles A.

2000-01-01

Eighty stocked lake trout Salvelinus namaycush (Salmonidae), collected from 2 locations in Lake Huron in May 1995, were examined for parasites. The parasite fauna of this top predator in Lake Huron was characterized by only 6 helminth species. Echinorhynchus salmonis infected all lake trout with a mean intensity of 163.9. The intensity of this acanthocephalan species significantly increased with host length and weight. Eubothrium salvelini infected 78 lake trout with a maximum number of 81 scoleces counted. Diplostomum sp., Cyathocephalus truncatus, Capillaria salvelini, and Neoechinorhynchus sp. infrequently infected lake trout. The low parasite species richness in these lake trout is believed to be due to their large size at stocking and to the loss of historical enzootic host-parasite relationships that followed the absence of this fish species in Lake Huron for 26 yr.

A gene-based SNP resource and linkage map for the copepod Tigriopus californicus

PubMed Central

2011-01-01

Background As yet, few genomic resources have been developed in crustaceans. This lack is particularly evident in Copepoda, given the extraordinary numerical abundance, and taxonomic and ecological diversity of this group. Tigriopus californicus is ideally suited to serve as a genetic model copepod and has been the subject of extensive work in environmental stress and reproductive isolation. Accordingly, we set out to develop a broadly-useful panel of genetic markers and to construct a linkage map dense enough for quantitative trait locus detection in an interval mapping framework for T. californicus--a first for copepods. Results One hundred and ninety Single Nucleotide Polymorphisms (SNPs) were used to genotype our mapping population of 250 F2 larvae. We were able to construct a linkage map with an average intermarker distance of 1.8 cM, and a maximum intermarker distance of 10.3 cM. All markers were assembled into linkage groups, and the 12 linkage groups corresponded to the 12 known chromosomes of T. californicus. We estimate a total genome size of 401.0 cM, and a total coverage of 73.7%. Seventy five percent of the mapped markers were detected in 9 additional populations of T. californicus. Of available model arthropod genomes, we were able to show more colocalized pairs of homologues between T. californicus and the honeybee Apis mellifera, than expected by chance, suggesting preserved macrosynteny between Hymenoptera and Copepoda. Conclusions Our study provides an abundance of linked markers spanning all chromosomes. Many of these markers are also found in multiple populations of T. californicus, and in two other species in the genus. The genomic resource we have developed will enable mapping throughout the geographical range of this species and in closely related species. This linkage map will facilitate genome sequencing, mapping and assembly in an ecologically and taxonomically interesting group for which genomic resources are currently under development

Pseudocyclops schminkei (Copepoda, Calanoida, Pseudocyclopidae): a new species from Okinawa

NASA Astrophysics Data System (ADS)

Chullasorn, Supawadee; Ferrari, Frank D.; Dahms, Hans-Uwe

2010-03-01

Both genders of Pseudocyclops schminkei n. sp. are described from a pearl fishery aquarium on Zamami Island, Okinawa, Japan; it is the 37th species of the genus. Pseudocyclops schminkei sp. nov. differs from other species of the magnus species group in the shape of the lobes of distal exopodal segment of the male left leg 5, and the morphology of setae on middle and distal exopodal segment of male right swimming leg 2. Aspects of the morphology of P. xiphophorus and P. bilobatus are redescribed, and an unnamed Pseudocyclops sp. from the Shedd Aquarium in Chicago, IL, is briefly noted. Females of P. schminkei sp. nov., P. xiphophorus and Pseudocyclops sp. could not be separated from each other with the small number of specimens available in this study for the former two species.

A 200K SNP chip reveals a novel Pacific salmon louse genotype linked to differential efficacy of emamectin benzoate.

PubMed

Messmer, Amber M; Leong, Jong S; Rondeau, Eric B; Mueller, Anita; Despins, Cody A; Minkley, David R; Kent, Matthew P; Lien, Sigbjørn; Boyce, Brad; Morrison, Diane; Fast, Mark D; Norman, Joseph D; Danzmann, Roy G; Koop, Ben F

2018-04-16

Antiparasitic drugs such as emamectin benzoate (EMB) are relied upon to reduce the parasite load, particularly of the sea louse Lepeophtheirus salmonis, on farmed salmon. The decline in EMB treatment efficacy for this purpose is an important issue for salmon producers around the world, and particularly for those in the Atlantic Ocean where widespread EMB tolerance in sea lice is recognized as a significant problem. Salmon farms in the Northeast Pacific Ocean have not historically experienced the same issues with treatment efficacy, possibly due to the relatively large population of endemic salmonid hosts that serve to both redistribute surviving lice and dilute populations potentially under selection by introducing naïve lice to farms. Frequent migration of lice among farmed and wild hosts should limit the effect of farm-specific selection pressures on changes to the overall allele frequencies of sea lice in the Pacific Ocean. A previous study using microsatellites examined L. salmonis oncorhynchi from 10 Pacific locations from wild and farmed hosts and found no population structure. Recently however, a farm population of sea lice was detected where EMB bioassay exposure tolerance was abnormally elevated. In response, we have developed a Pacific louse draft genome that complements the previously-released Atlantic louse sequence. These genomes were combined with whole-genome re-sequencing data to design a highly sensitive 201,279 marker SNP array applicable for both subspecies (90,827 validated Pacific loci; 153,569 validated Atlantic loci). Notably, kmer spectrum analysis of the re-sequenced samples indicated that Pacific lice exhibit a large within-individual heterozygosity rate (average of 1 in every 72 bases) that is markedly higher than that of Atlantic individuals (1 in every 173 bases). The SNP chip was used to produce a high-density map for Atlantic sea louse linkage group 5 that was previously shown to be associated with EMB tolerance in Atlantic lice

The Meristogram: a neglected tool for acanthocephalan systematics

PubMed Central

2016-01-01

Abstract Background The hooks of the acanthocephalan proboscis exhibit serial variation in size and shape. The Meristogram was developed by Huffman and Bullock (1975) to provide a graphical representation of this positional variation in hook morphology. Initial studies demonstrated the ability of the Meristogram to discriminate species within the genera Echinorhynchus and Pomphorhynchus (Huffman and Bullock 1975, Huffman and Nickol 1978, Gleason and Huffman 1981). However, the reliability of the method for taxonomic work was questioned by Shostak et al. (1986) after they found intra-specific variation in two Echinorhynchus species. Uncertainty about the usefulness of the Meristogram and the absence of a readily available software implementation of the algorithm, might explain why this abstract proboscis character has yet to be adopted by acanthocephalan systematists. New information The Meristogram algorithm was implemented in the R language and a simple graphical user interface created to facilitate ease of use (the software is freely available from https://github.com/WaylandM/meristogram). The accuracy of the algorithm's formula for calculating hook cross-sectional area was validated by data collected using a digitizing tablet. Meristograms were created from data in public respositories for eight Echinorhynchus taxa: E. bothniensis, E. 'bothniensis', E. gadi spp. A, B and I, E. brayi, E. salmonis and E. truttae. In this preliminary analysis, the meristogram differentiated E. bothniensis, E. brayi, E. gadi sp. B, E. salmonis and E. truttae from each other, and from the remaining taxa in this study, but independent data will be required for validation. Sample sizes for E. 'bothniensis' and E. gadi spp. A and I were too small to identify diagnostic features with any degree of confidence. Meristogram differences among the sibling species of the E. gadi and E. bothniensis groups suggest that the 'intra-specfic' variation in meristogram previously reported for some

Sea-louse parasites on juvenile wild salmon in the Broughton Archipelago, British Columbia, Canada.

PubMed

Peacock, Stephanie J; Bateman, Andrew W; Krkošek, Martin; Connors, Brendan; Rogers, Scott; Portner, Lauren; Polk, Zephyr; Webb, Coady; Morton, Alexandra

2016-07-01

The global expansion of aquaculture has changed the structure of fish populations in coastal environments, with implications for disease dynamics. In Pacific Canada, farmed salmon act as reservoir hosts for parasites and pathogens, including sea lice (Lepeophtheirus salmonis and Caligus clemensi) that can transmit to migrating wild salmon. Assessing the impact of salmon farms on wild salmon requires regular monitoring of sea-louse infections on both farmed and wild fish. Since 2001, we have collected juvenile pink (Oncorhynchus gorbuscha) and chum (O. keta) salmon annually at three sites in the Broughton Archipelago in British Columbia, Canada, during the annual juvenile salmon migration from fresh water to the open ocean. From sampled fish, we recorded counts of parasitic copepodid-, chalimus-, and motile-stage sea lice. We report louse abundances as well as supplementary observations of fish size, development, and health. © 2016 by the Ecological Society of America.

Sea louse control in Scotland, past and present.

PubMed

Rae, Gordon H

2002-06-01

Methods for farming the Atlantic salmon (Salmo salar L) in Scotland were developed at the Unilever Research Laboratory facility at Lochailort on the west coast of Scotland in the late 1960s. By the spring of 1972 a fledgling commercial company had been set up and Marine Harvest, as it was known, received its first year class of smolts at Lochailort. Sea lice (Lepeophtheirus salmonis Krøyer) from passing wild fish infected the smolts but did not cause any significant damage until the summer of 1976 when intervention was required. The Scottish industry has since grown to become a vital source of employment for fragile rural economies and produced about 130,000 tonnes of salmon in 2000. This paper gives an overview of how fish welfare has been maintained by the development of treatments and management strategies aimed at minimising the impact of sea lice.

Population Dynamics and Production of the Amphipod Corophium salmonis in Grays Harbor, Washington,

DTIC Science & Technology

1981-09-01

biomass ratios of bivalve and gastropod population in an eastern Canadian estuary. J. Fish. Res. Bd. Can. 31: 167-177. Casablanca, M. -L., de. 1975...analysis was adapted from "Standards Methods for the Examination of Water and Wastewater," 14th Edition, APHA, AWWA, and WPCF, Washington, D.C., 1975, pp

Adaptive significance of color polymorphism in two species of Diaptomus (copepoda)

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hairston, N.G. Jr.

In the Lower Grande Coulee, Washington, Diaptomus nevadensis in Soap Lake contains larger amounts of the carotenoid astaxanthin than in Lake Lenore. During winter, Diaptomus sicilis contains larger amounts of pigment in both lakes, but in summer individuals from Lake Lenore are much reduced in pigment while those from Soap Lake are unchanged. Seasonal variations in copepod carotenoid content did not correspond with variations in total lipid content. Algal abundance was measured by chlorophyll a and plant carotenoids correlated with copepod carotenoids only in the case of D. nevadensis in Soap Lake. The percent of D. nevadensis guts containing algaemore » was correlated with their pigment content in both lakes. Visually oriented predators, such as damselfly nymphs from both lakes and salamander larvae from Lake Lenore, selected red copepods, but few predators from Lake Lenore contained D. nevadensis. Since members of this species were rare, the probability of finding a predator that had consumed one was low. When fed identical diets, copepods from Lake Lenore were a fifth to a thirtieth as efficient at assimilating carotenoid as those from Soap Lake. This supports the hypothesis that the pigment differences are the result of natural selection. Selective predation is implicated as the explanation for the small amounts of pigment in Lake Lenore copepods.« less

The status of Limnocalanus macrurus (Copepoda: Calanoida: Centropagidae) in Lake Erie

USGS Publications Warehouse

Kane, Douglas D.; Gannon, John E.; Culver, David A.

2004-01-01

The calanoid copepod Limnocalanus macrurus showed large declines in abundance and a narrowing of spatial distribution with the onset of cultural eutrophication and increases in rainbow smelt (Osmerus mordax) abundances in Lake Erie in the mid 20th century. Since 1995, however, Limnocalanus macrurus appears to have repopulated in western Lake Erie to levels of abundance that have not been observed since the late 1930s. We hypothesize that phosphorus abatement and the subsequent decrease in low dissolved oxygen events have assisted this resurgence. However, Limnocalanus macrurusabundances have not increased in the central and eastern basins, even though water quality has improved there too. High densities of rainbow smelt and associated smelt predation pressure in the central and eastern basins may be responsible for the low numbers in these basins.

Negligible effects of ocean acidification on Eurytemora affinis (Copepoda) offspring production

NASA Astrophysics Data System (ADS)

Almén, Anna-Karin; Vehmaa, Anu; Brutemark, Andreas; Bach, Lennart; Lischka, Silke; Stuhr, Annegret; Furuhagen, Sara; Paul, Allanah; Bermúdez, J. Rafael; Riebesell, Ulf; Engström-Öst, Jonna

2016-02-01

Ocean acidification is caused by increasing amounts of carbon dioxide dissolving in the oceans leading to lower seawater pH. We studied the effects of lowered pH on the calanoid copepod Eurytemora affinis during a mesocosm experiment conducted in a coastal area of the Baltic Sea. We measured copepod reproductive success as a function of pH, chlorophyll a concentration, diatom and dinoflagellate biomass, carbon to nitrogen (C : N) ratio of suspended particulate organic matter, as well as copepod fatty acid composition. The laboratory-based experiment was repeated four times during 4 consecutive weeks, with water and copepods sampled from pelagic mesocosms enriched with different CO2 concentrations. In addition, oxygen radical absorbance capacity (ORAC) of animals from the mesocosms was measured weekly to test whether the copepod's defence against oxidative stress was affected by pH. We found no effect of pH on offspring production. Phytoplankton biomass, as indicated by chlorophyll a concentration and dinoflagellate biomass, had a positive effect. The concentration of polyunsaturated fatty acids in the females was reflected in the eggs and had a positive effect on offspring production, whereas monounsaturated fatty acids of the females were reflected in their eggs but had no significant effect. ORAC was not affected by pH. From these experiments we conclude that E. affinis seems robust against direct exposure to ocean acidification on a physiological level, for the variables covered in the study. E. affinis may not have faced acute pH stress in the treatments as the species naturally face large pH fluctuations.

Negligible effects of ocean acidification on Eurytemora affinis (Copepoda) offspring production

NASA Astrophysics Data System (ADS)

Almén, A.-K.; Vehmaa, A.; Brutemark, A.; Bach, L.; Lischka, S.; Stuhr, A.; Furuhagen, S.; Paul, A.; Bermúdez, R.; Riebesell, U.; Engström-Öst, J.

2015-10-01

Ocean acidification is caused by increasing amounts of carbon dioxide dissolving in the oceans leading to lower seawater pH. We studied the effects of lowered pH on the calanoid copepod Eurytemora affinis during a mesocosm experiment conducted in a coastal area of the Baltic Sea. We measured copepod reproductive success as a function of pH, chlorophyll a concentration, diatom and dinoflagellate biomass, carbon to nitrogen (C : N) ratio of suspended particulate organic matter, as well as copepod fatty acid composition. The laboratory-based experiment was repeated four times during four consecutive weeks, with water and copepods sampled from pelagic mesocosms enriched with different CO2 concentrations. In addition, oxygen radical absorbance capacity (ORAC) of animals from the mesocosms was measured weekly to test whether the copepod's defence against oxidative stress was affected by pH. We found no effect of pH on offspring production. Phytoplankton biomass, as indicated by chlorophyll a concentration, had a strong positive effect. The concentration of polyunsaturated fatty acids in the females were reflected in the eggs and had a positive effect on offspring production, whereas monounsaturated fatty acids of the females were reflected in their eggs but had no significant effect. ORAC was not affected by pH. From these experiments we conclude that E. affinis seems robust against direct exposure to ocean acidification on a physiological level, for the variables covered in the study. E. affinis may not have faced acute pH stress in the treatments as the species naturally face large pH fluctuations.

Cyclopidae (Crustacea, Copepoda) from the upper Paraná River floodplain, Brazil.

PubMed

Lansac-Tôha, F A; Velho, L F M; Higuti, J; Takahashi, E M

2002-02-01

Cyclopid copepods from samples of fauna associated with aquatic macrophytes and plancton obtained in lotic and lentic environments were obtained from the upper Paraná River floodplain (in the states of Paraná and Mato Grosso do Sul, Brazil). Macrophytes were collected in homogeneous stands and washed. Plankton samples, taken from the water column surface and bottom, were obtained using a motor pump, with a 70 microns mesh plankton net for filtration. Twelve taxa of Cyclopidae were identified. Among them, Macrocyclops albidus albidus, Paracyclops chiltoni, Ectocyclops rubescens, Homocyclops ater, Eucyclops solitarius, Mesocyclops longisetus curvatus, Mesocyclops ogunnus, and Microcyclops finitimus were new finds for this floodplain. Eight species were recorded exclusively in aquatic macrophyte samples. Among these species, M. albidus albidus and M. finitimus presented greatest abundances. Only four species were recorded in plankton samples, and Thermocyclops minutus and Thermocyclops decipiens are limited to this type of habitat. Among these four species, T. minutus is the most abundant, especially in lentic habitats.

Zoo-heleoplankton structure in three artificial ponds of North-eastern Argentina.

PubMed

Frutos, S M; Carnevali, R

2008-09-01

The aim of the present study was to compare the abundance and species richness of zoo-heleoplankton bigger than 53 microm in an annual cycle under similar climate conditions in three artificial ponds, in order to observe the changes during an annual cycle. Samples were taken monthly from June 1993 to July 1994 in Corrientes, Argentina. The first pond (A) was covered an 80% by Eichhornia crassipes (Mart.), the second one (B) with bloom of Microcystis aeruginosa (Kurtzing) and the last one (C) with organic matter deposited in the bottom. The water was more acidic at pond A, and the water at pond B contained more dissolved oxygen concentration than the water at the other two ponds. The zoo-heleoplankton densities varied between 20-1728 ind.l(-1) at pond A, 42-4082 ind.l(-1) at pond B and 148-2447 ind.l(-1) at pond C. The maximum zoo-heleoplankton abundance was found in the pond with cyanobacteria bloom during Autumn 1994 and the minimum abundance was found in the one with a predominance of E. crassipes. The rank of species richness was pond A > pond B > pond C. Rotifera was the most abundant group in pond A whereas the larval stages of Copepoda were abundant in the other two ponds. Anuraeopsis navicula Rousselt 1910 was the dominant population in the pond with macrophytes prevalence. Brachionus calyciflorus Pallas 1776 and larval stage of Copepoda had variable proportions in the pond with cyanobacteria bloom. Thermocyclops decipiens (Kiefer 1929) was present during the annual cycle only in the pond with organic matter deposited in the bottom. The succession of taxa was observed in the pond with coverage of aquatic macrophytes and with cyanobacteria bloom. Differences in species richness and low similarity in zoo-heleoplankton between ponds were determined by differences in the quality of the water in relation to the presence of macrophytes, cyanobacteria, organic matter deposited in the bottom and fish predation. Multiple regression analysis (stepwise) revealed that

Critical thresholds in sea lice epidemics: evidence, sensitivity and subcritical estimation

PubMed Central

Frazer, L. Neil; Morton, Alexandra; Krkošek, Martin

2012-01-01

Host density thresholds are a fundamental component of the population dynamics of pathogens, but empirical evidence and estimates are lacking. We studied host density thresholds in the dynamics of ectoparasitic sea lice (Lepeophtheirus salmonis) on salmon farms. Empirical examples include a 1994 epidemic in Atlantic Canada and a 2001 epidemic in Pacific Canada. A mathematical model suggests dynamics of lice are governed by a stable endemic equilibrium until the critical host density threshold drops owing to environmental change, or is exceeded by stocking, causing epidemics that require rapid harvest or treatment. Sensitivity analysis of the critical threshold suggests variation in dependence on biotic parameters and high sensitivity to temperature and salinity. We provide a method for estimating the critical threshold from parasite abundances at subcritical host densities and estimate the critical threshold and transmission coefficient for the two epidemics. Host density thresholds may be a fundamental component of disease dynamics in coastal seas where salmon farming occurs. PMID:22217721

Effects of parasites from salmon farms on productivity of wild salmon

PubMed Central

Krkošek, Martin; Connors, Brendan M.; Morton, Alexandra; Lewis, Mark A.; Dill, Lawrence M.; Hilborn, Ray

2011-01-01

The ecological risks of salmon aquaculture have motivated changes to management and policy designed to protect wild salmon populations and habitats in several countries. In Canada, much attention has focused on outbreaks of parasitic copepods, sea lice (Lepeophtheirus salmonis), on farmed and wild salmon in the Broughton Archipelago, British Columbia. Several recent studies have reached contradictory conclusions on whether the spread of lice from salmon farms affects the productivity of sympatric wild salmon populations. We analyzed recently available sea lice data on farms and spawner–recruit data for pink (Oncorhynchus gorbuscha) and coho (Oncorhynchus kisutch) salmon populations in the Broughton Archipelago and nearby regions where farms are not present. Our results show that sea lice abundance on farms is negatively associated with productivity of both pink and coho salmon in the Broughton Archipelago. These results reconcile the contradictory findings of previous studies and suggest that management and policy measures designed to protect wild salmon from sea lice should yield conservation and fishery benefits. PMID:21873246

Diversity of bacteria in ships ballast water as revealed by next generation DNA sequencing.

PubMed

Brinkmeyer, Robin

2016-06-15

The bacterial diversity in ballast water from five general cargo ships calling at the Port of Houston was determined with ion semiconductor DNA sequencing (Ion Torrent PGM) of PCR amplified 16S rRNA genes. Phylogenetic analysis revealed that the composition of bacteria in ballast water did not resemble that of typical marine habitats or even open ocean waters where BWEs occur. The predominant group of bacteria in ships conducting BWEs was the Roseobacter clade within the Alphaproteobacteria. In contrast, Gammaproteobacteria were predominant in the ship that did not conduct a BWE. All the ships contained human, fish, and terrestrial plant pathogens as well as bacteria indicative of fecal or activated sludge contamination. Most of the 60 pathogens had not been detected in ballast water previously. Among these were the human pathogens Corynebacterium diptheriae and several Legionella species and the fish pathogens Francisella piscicida and Piscirickettsia salmonis. Copyright © 2016 Elsevier Ltd. All rights reserved.

Work package 4 report: Broodfish testing for bacterial infections

USGS Publications Warehouse

Michel, Christian; Elliott, Diane G.; Jansson, Eva; Urdaci, Maria; Midtlyng, Paul J.

2005-01-01

This report summarises current scientific information and experience obtained with various methods for testing of salmonid broodfish or spawn for bacterial kidney disease (BKD - Renibacterium salmoninarum infection) in order to prevent vertical transmission of the organism to the offspring. Assessment is also being performed for Flavobacterium psychrophilum infections causing rainbow trout fry syndrome (RTFS) or bacterial coldwater disease (CWD), and for Piscirickettsia salmonis infection causing salmon rickettsial syndrome (SRS) in salmonid fish species. Methods for screening to document the absence of BKD in fish populations are well established. Some of them have also proven successful for testing individual fish from infected populations in order to avoid vertical transmission of the infectious agent. Several diagnostic methods for flavobacteriosis and piscirickettsiosis have also been established but none of them, as yet, has been validated for use in programmes to prevent vertical transmission of disease. Priority subjects for further research in order to improve the management and control of these vertically transmissible fish diseases are suggested.

Oral vaccination of Atlantic salmon (Salmo salar) against salmonid rickettsial septicaemia.

PubMed

Tobar, Jaime A; Jerez, Sofía; Caruffo, Mario; Bravo, Catalina; Contreras, Francisco; Bucarey, Sergio A; Harel, Moti

2011-03-09

Effective oral immunization systems may be very helpful to the salmon industry, particularly during the seawater growth stages in which vaccination through injection is not possible. During the seawater growing stage, fish become more susceptible to several types of disease, due to the natural decay of vaccine-induced immune responses. In this study, we demonstrate the immune response and efficacy of a new salmonid rickettsial septicaemia (SRS) oral vaccine, developed using MicroMatrix™ Technology. The vaccine, which is administered together with daily feed ration, induces a specific immune response at local and systemic levels. Anti-Piscirickettsia salmonis specific antibodies were detected as soon as 300 degree-days after vaccination. Furthermore, oral vaccination was able to protect fish against a lethal pathogen challenge when administered either as a primary vaccination or as a booster for an injected vaccine. Results show that oral vaccination is an efficacious treatment for the prevention of SRS outbreaks throughout the salmon culture period. Copyright © 2010 Elsevier Ltd. All rights reserved.

Epipelagic mesozooplankton succession and community structure over a marine ouffall area in the northeastern South China Sea.

PubMed

Tseng, Li Chun; Kumar, Ram; Dahms, Hans Uwe; Chen, Chun Te; Chen, Qing Chao; Hwang, Jiang Shiou

2008-05-01

This study analyses distribution and abundance patterns of mesozooplankton communities at 13 stations in the coastal waters over a marine outfall area in the northeastern South China Sea. Cruises were conducted in March, June and September 2002, and plankton samples were collected with a 333 microm North Pacific net. The Mesozooplankton was dominated by calanoid Copepods, Cladocera, Chaetognatha and Pteropoda. Stations located near the entrance of the harbor provided a relatively higher abundance of Noctilucales and Radiolarians. In total, 20 zooplankton groups were identified in which, Calanoida, Cladocera, Chaetognatha, Pteropoda, Poecilostomatoida and Appendicularia comprised 92.77% of the total zooplankton abundance. Copepoda dominated in all three cruises, comprising 65.32% of the total mesozooplankton abundance. Samples collected in June recorded higher mesozooplankton abundance than March and September samples. Onshore stations recorded higher BOD values, higher abundance of Noctilucales and Radiolarians and a relativelylower abundance of the overall mesozooplankton. Total mesozooplankton abundance did not correlate significantly with temperature, pH, or dissolved oxygen, but correlated negatively with BOD.

Mobile epifauna on Zostera marina, and infauna of its inflorescences

NASA Astrophysics Data System (ADS)

Hellwig-Armonies, Monika

1988-06-01

The faunal colonization of the leaves and inflorescences of intertidal Zostera marina L. and of the ambient water has been studied at the Island of Sylt (North Sea). The abundance of the snail Littorina littorea L. and the isopod Jaera albifrons Leach correlates significantly with leaf surface area. This is not the case with the abundance of meiofaunal Plathelminthes, Nematoda, Copepoda, and Polychaeta. However, they increase significantly with the numbers of generative shoots in the sampled seagrass bunches. Members of these taxa inhabit the Zostera inflorescences, and average abundance increases with the degree of decay of inflorescences. This temporary microhabitat presumably offers food and shelter. Copepods and ostracods dominate in the ambient water. Planktonic calanoid copepods correlate with the amount of sampled seawater, while Ostracoda correlate with the amount of resuspended detritus suggesting that they were resuspended themselves. The study shows that some meiofaunal taxa can rapidly exploit a short-lived habitat such as the Zostera inflorescences. Juvenile polychaetes use inflorescences as a nursery.

Food of forage fishes in western Lake Erie, 1975-76

USGS Publications Warehouse

Muth, Kenneth M.; Busch, Wolf-Dieter N.

1989-01-01

In western Lake Erie in the summer and fall of 1975–1976, food eaten by seven forage fishes—emerald shiner (Notropis atherinoides), spottail shiner (Notropis hudsonius), trout-perch (Percopsis omiscomaycus), andyoung-of-the-year (YOY) of alewife (Alosa pseudoharengus), gizzard shad (Dorosoma cepedianum), white bass (Morone chrysops), and freshwater drum (Aplodi-notus grunniens)—was divided among six major taxa: Cladocera, Copepoda, Diptera, Ostracoda, Amphipoda, and Algae. In addition, fish were eaten by YOY white bass, and Rotifera were consumed by YOY gizzard shad. Interspecies diet overlap indices, calculated to compare the food of the different species and to evaluate diet similarities, were usually highest for YOY white bass and YOY freshwater drum when compared with the other species and usually lowest between emerald shiners and all other forage fishes. Understanding the feeding interactions among fishes that could influence production at the forage-food level of the food web could provide insight into how cascading trophic interactions influence the production of piscivorous predators.

Pancrustacean phylogeny: hexapods are terrestrial crustaceans and maxillopods are not monophyletic

PubMed Central

Regier, Jerome C.; Shultz, Jeffrey W.; Kambic, Robert E.

2005-01-01

Recent molecular analyses indicate that crustaceans and hexapods form a clade (Pancrustacea or Tetraconata), but relationships among its constituent lineages, including monophyly of crustaceans, are controversial. Our phylogenetic analysis of three protein-coding nuclear genes from 62 arthropods and lobopods (Onychophora and Tardigrada) demonstrates that Hexapoda is most closely related to the crustaceans Branchiopoda (fairy shrimp, water fleas, etc.) and Cephalocarida+Remipedia, thereby making hexapods terrestrial crustaceans and the traditionally defined Crustacea paraphyletic. Additional findings are that Malacostraca (crabs, isopods, etc.) unites with Cirripedia (barnacles, etc.) and they, in turn, with Copepoda, making the traditional crustacean class Maxillopoda paraphyletic. Ostracoda (seed shrimp)—either all or a subgroup—is associated with Branchiura (fish lice) and likely to be basal to all other pancrustaceans. A Bayesian statistical (non-clock) estimate of divergence times suggests a Precambrian origin for Pancrustacea (600 Myr ago or more), which precedes the first unambiguous arthropod fossils by over 60 Myr. PMID:15734694

Mating behaviour of Pseudodiaptomus annandalei (Copepoda, Calanoida) in calm and turbulent waters

NASA Astrophysics Data System (ADS)

Lee, C. H.; Dahms, H. U.; Cheng, S. H.; Souissi, S.; Schmitt, F. G.; Kumar, R.; Hwang, J. S.

2009-04-01

Behavioral observations of male copepods reveal that they commonly follow female copepods' footprints to find their mates. Female generated environmental signals are primarily of hydromechanical or chemical quality. The intensity of hydromechanical or chemical signals is affected by the hydrodynamic conditions which in turn may modulate a copepod's ability to sense signals in their search for mates in the aquatic environment. We studied the patterns and efficiency of the copepod Pseudodiaptomus annandalei to mate at still and turbulent water conditions during day and night and in different shape and volume experimental containers. The ability of courtship in P. annandalei was recorded to be a negative function of hydromechanical disturbances as the successful mating was observed in still water only. Under turbulent condition males were not able to track a female properly. We records in the present study that both, sequential and simultaneous taxi mechanisms are used by the male P. annandalei to follow either hydromechanic or chemical signals. Our results further reveal that males follow a signal more accurately characterized as a trail. The ability of P. annandalei males to track a three-dimensional trail appears unique, and possibly depends on the persistence of fluid-borne hydromechanical or chemical signals created in low Reynolds number hydrodynamic regimes. Keywords: Mating behavior, Turbulence, Flow, Hydrodynamic conditions

A new species of Notodiaptomus from the Ecuadorian Andes (Copepoda, Calanoida, Diaptomidae).

PubMed

Alonso, Miguel; Dos Santos-Silva, Edinaldo N; Jaume, Damià

2017-01-01

Notodiaptomus cannarensis sp. n. is described from a reservoir on the Amazonian slope of the Ecuadorian Andes. The new species is unique among diaptomid calanoid copepods in the display of hypertrophied, symmetrical wing-like extensions at each side of the female composite genital somite. Furthermore, it displays a female urosome reduced to only two somites due to the incorporation of abdominal somites III and IV to the composite genital double-somite, and a male right fifth leg with the outer spine of second exopodal segment recurved and implanted proximally on margin. It differs from any other Notodiaptomus in the display of a large rectangular lamella on proximal segment of exopod of male right fifth leg. The species is currently known only from Mazar reservoir, a eutrophic water body placed above 2127 m a.s.l. on the River Paute (Cañar Province; southern Ecuador), where it is the most common crustacean in the water column.

A new species of Notodiaptomus from the Ecuadorian Andes (Copepoda, Calanoida, Diaptomidae)

PubMed Central

Alonso, Miguel; dos Santos-Silva, Edinaldo N.; Jaume, Damià

2017-01-01

Abstract Notodiaptomus cannarensis sp. n. is described from a reservoir on the Amazonian slope of the Ecuadorian Andes. The new species is unique among diaptomid calanoid copepods in the display of hypertrophied, symmetrical wing-like extensions at each side of the female composite genital somite. Furthermore, it displays a female urosome reduced to only two somites due to the incorporation of abdominal somites III and IV to the composite genital double-somite, and a male right fifth leg with the outer spine of second exopodal segment recurved and implanted proximally on margin. It differs from any other Notodiaptomus in the display of a large rectangular lamella on proximal segment of exopod of male right fifth leg. The species is currently known only from Mazar reservoir, a eutrophic water body placed above 2127 m a.s.l. on the River Paute (Cañar Province; southern Ecuador), where it is the most common crustacean in the water column. PMID:29134016

Mating behaviour of Pseudodiaptomus annandalei (Copepoda Calanoida) with emphasis on rejection rate

NASA Astrophysics Data System (ADS)

Dur, G.; Souissi, S.; Schmitt, F. G.; Hwang, J. S.; Cheng, S. H.

2009-04-01

Mating behaviour has important consequences at both individual and population levels. Reproductive fitness is of paramount importance to sustain the success of planktonic copepod populations in aquatic environments. The calanoid copepod Pseudodiaptomus annandalei has one of the largest geographical ranges for Indo-Pacific Pseudodiaptomidae. It is also of great importance in fish culture pounds south of Taiwan. However, the mating behavior of this species has never been studied. Mating and predatory behaviour are conceptually the same. In both cases, the encounter and the interactions occur between two individuals with opposite characteristics: predator-prey for predation; male-female for mating. The mating behaviour may be defined as a sequence of encounter, pursuit, capture and copulation. Several observed behaviour suggest that both sexes asses and choose among available mates before the copulation. Pre-copulatory mate choice in copepods may manifest as mate guarding where males attached to CV females until their final moult, complicated pre-copulatory dance and escaping. During our preliminary observations, we notice that P. annandalei females escape by shaking, often violently, the males that have caught them. Consequently for such a species the act of mating may be visualized as a chain of six events (i.e. search, encounter, pursuit, capture, selective dance, copulation).Within this chain, encounter, capture and copulation are conditional events depending on the successful conclusion of their preceding events in the chain. In this study, we examined the different step in the mating behaviour of the scarcely studied sub-tropical copepod, Pseudodiaptomus annandalei, collected from the Danshuei estuary (North Taiwan). The individuals were observed using a 3D optical system to obtain simultaneous front and side views. Males, when placed in the water where females had previously swum in, showed significant increase of their swimming velocities. Additionally, their swimming trajectories are more convoluted, indicating that males explore larger volume of fluid to increase the probability to encounter a female. The mate finding behaviour appears to depend not only on chemical signal but also on hydromechanical signals. Some males exhibited shifts of direction when females were passing by. When male intercepted a chemical trail left by a female, they initiate tracking behaviour racing up the trail with increasing speed. Males pursued pheromone trails up to 24 sec old and 10 mm long. Most studies of mating behaviour have focused on detection and sometimes pursuit, but few have addressed the other components of successful mating, namely, capture and copulation. Moreover, mate choice issue has largely been ignored in regards to pelagic copepods. Consequently very few are known about the plasticity of rejection rates as a function of mate encounter rates. The second aim of this experiment is to describe the process used by female to select their mate and to fill the gap in the quantification of mating success. Once caught by a male, P. annandalei's females entered in intensive dance which sometimes lead to shake off the males suggesting a female mate choice. The three-dimensional trajectories described by the couple during this event were characterized by fast loops and intense jumps. Individual's access to mates may be affected by operational sex ratios, causing strong variation in mating success. We finally manipulated adult sex ratios of the brackish copepod P. annandalei, to examine the influence of population sex ratio on mating success of P. annandalei in a final set of experiment concluding the investigation. It should be notice that, to our knowledge, it the first quantification ever done before. The plasticity of rejection rate was therefore investigated as a function of sex-ratio and mate encounter rate. The encounter rate reached maximum value for balanced proportion of male and female and decreased as the sex ratio unbalanced. Higher value of success was nevertheless observed for a pro-male sex-ratio.

Monitoring of Downstream Salmon and Steelhead at Federal Hydroelectric Facilities, 1992 Annual Report.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hawkes, Lynnette A.; Martinson, Rick D.; Absolon, Randall F.

1993-05-01

The seaward migration of salmonid smolts was monitored by the National marine Fisheries Service (NMFS) at two sites on the Columbia River in 1992. The NMFS Smolt Monitoring Project is part of a larger Smolt Monitoring Program to index Columbia Basin juvenile salmonied stocks. It is coordinated by the Fish Passage Center (FPC) for the Columbia Basin Fish and Wildlife Agencies and Tribes. Its purpose is to facilitate fish passage through reservoirs and at dams by providing FPC with timely smolt migration data used for flow and spill management. Data is also used for travel time, migration timing and relativemore » run size magnitude analysis. This program is carried out under the auspices of the Northwest Power Planning Council Fish and Wildlife Program and is funded by the Bonneville Power Administration (BPA). Sampling sites were John Day and Bonneville Dams under the 1992 Smolt Monitoring Program. All pertinent fish capture, condition, brand recovery, and flow data, were reported daily to FPC. These data were incorporated into the FPC`s Fish Passage Data System (FPDS).« less

Fish immune responses to parasitic copepod (namely sea lice) infection.

PubMed

Fast, Mark D

2014-04-01

Parasitic copepods, in particular sea lice, have considerable impacts upon global freshwater and marine fisheries, with major economic consequences recognized primarily in aquaculture. Sea lice have been a contentious issue with regards to interactions between farmed and wild populations of fish, in particular salmonids, and their potential for detrimental effects at a population level. The following discussion will pertain to aquatic parasitic copepod species for which we have significant information on the host-parasite interaction and host response to infection (Orders Cyclopoida, Poecilostomatoida and Siphonostomatoida). This review evaluates prior research in terms of contributions to understanding parasite stage specific responses by the host, and in many cases draws upon model organisms like Lepeophtheirus salmonis and Atlantic salmon to convey important concepts in fish responses to parasitic copepod infection. The article discusses TH1 and TH2-like host responses in light of parasite immunomodulation of the host, current methods of immunological stimulation and where the current and future work in this field is heading. Copyright © 2013 Elsevier Ltd. All rights reserved.

In the shadow: The emerging role of long non-coding RNAs in the immune response of Atlantic salmon.

PubMed

Tarifeño-Saldivia, E; Valenzuela-Miranda, D; Gallardo-Escárate, C

2017-08-01

The genomic era has increased the research effort to uncover how the genome of an organism, and specifically the transcriptome, is modulated after interplaying with pathogenic microorganisms and ectoparasites. However, the ever-increasing accessibility of sequencing technology has also evidenced regulatory roles of long non-coding RNAs (lncRNAs) related to several biological processes including immune response. This study reports a high-confidence annotation and a comparative transcriptome analysis of lncRNAs from several tissues of Salmo salar infected with the most prevalent pathogens in the Chilean salmon aquaculture such as the infectious salmon anemia (ISA) virus, the intracellular bacterium Piscirickettsia salmonis and the ectoparasite copepod Caligus rogercresseyi. Our analyses showed that lncRNAs are widely modulated during infection. However, this modulation is pathogen-specific and highly correlated with immuno-related genes associated with innate immune response. These findings represent the first discovery for the widespread differential expression of lncRNAs in response to infections with different types of pathogens in Atlantic salmon, suggesting that lncRNAs are pivotal player during the fish immune response. Copyright © 2017 Elsevier Ltd. All rights reserved.

Increased susceptibility to infectious salmon anemia virus (ISAv) in Lepeophtheirus salmonis – infected Atlantic salmon

USDA-ARS?s Scientific Manuscript database

The salmon louse and infectious salmon anemia virus (ISAv) are the two most significant pathogens of concern to the Atlantic salmon (Salmo salar) aquaculture industry. However, the interactions between sea lice and ISAv, as well as the impact of a prior sea lice infection on the susceptibility of th...

Aquaporin family genes exhibit developmentally-regulated and host-dependent transcription patterns in the sea louse Caligus rogercresseyi.

PubMed

Farlora, Rodolfo; Valenzuela-Muñoz, Valentina; Chávez-Mardones, Jacqueline; Gallardo-Escárate, Cristian

2016-07-01

Aquaporins are small integral membrane proteins that function as pore channels for the transport of water and other small solutes across the cell membrane. Considering the important roles of these proteins in several biological processes, including host-parasite interactions, there has been increased research on aquaporin proteins recently. The present study expands on the knowledge of aquaporin family genes in parasitic copepods, examining diversity and expression during the ontogeny of the sea louse Caligus rogercresseyi. Furthermore, aquaporin expression was evaluated during the early infestation of Atlantic (Salmo salar) and Coho salmon (Oncorhynchus kisutch). Deep transcriptome sequencing data revealed eight full length and two partial open reading frames belonging to the aquaporin protein family. Clustering analyses with identified Caligidae sequences revealed three major clades of aquaglyceroporins (Cr-Glp), classical aquaporin channels (Cr-Bib and Cr-PripL), and unorthodox aquaporins (Cr-Aqp12-like). In silico analysis revealed differential expression of aquaporin genes between developmental stages and between sexes. Male-biased expression of Cr-Glp1_v1 and female-biased expression of Cr-Bib were further confirmed in adults by RT-qPCR. Additionally, gene expressions were measured for seven aquaporins during the early infestation stage. The majority of aquaporin genes showed significant differential transcription expressions between sea lice parasitizing different hosts, with Atlantic salmon sea lice exhibiting overall reduced expression as compared to Coho salmon. The observed differences in the regulation of aquaporin genes may reveal osmoregulatory adaptations associated with nutrient ingestion and metabolite waste export, exposing complex host-parasite relationships in C. rogercresseyi. Copyright © 2016 Elsevier B.V. All rights reserved.

Niche separation and reproduction of Clausocalanus species (Copepoda, Calanoida) in the Atlantic Ocean

NASA Astrophysics Data System (ADS)

Peralba, Àurea; Mazzocchi, Maria Grazia; Harris, Roger P.

2017-11-01

The distribution and reproductive traits of copepods of the genus Clausocalanus were investigated during the Atlantic Meridional Transect cruise AMT-15, in September-October 2004 to estimate their ecological niches and secondary production in the epipelagic layer along a latitudinal cline (48°N-40°S). The distribution patterns of selected environmental parameters, i.e., temperature, salinity and chlorophyll a concentration, enabled eco-provinces to be identified as described by Longhurst (2006). Clausocalanus represented on average 34% of total copepod abundance, with a large predominance of adult females and copepodites over males. Among the eleven Clausocalanus species found during the survey, eight species showed a wide distributional range, i.e.,C. paululus, C. pergens, C. furcatus, C. arcuicornis, C. jobei, C. parapergens, C. lividus, and C. mastigophorus, while C. ingens, C. brevipes, and C. laticeps were recorded only in the South Atlantic. The smallest C. furcatus, C. paululus, and C. pergens together accounted for 85% of total Clausocalanus adult abundance. The ecological niches were clearly separated among congeners of similar size and largely overlapped in congeners whose size differed. The small- and medium-sized species, which are egg-sac-spawners, had smaller clutch size and lower egg-production rate than the larger broadcaster congeners. Nevertheless, embryo viability was lower in broadcasters, which may explain their low abundance in terms of lower recruitment. A sex ratio largely skewed toward females in all Clausocalanus species and the observation of viable eggs in successive clutches from isolated females seem to indicate that re-mating is not necessary in this genus. Broadcast-spawners showed the highest weight-specific fecundity rates in the genus but similar secondary production to sac-spawners despite the fact that they never occurred at high abundance. In light of their abundant occurrence in oceanic waters and well-defined ecological niches, Clausocalanus species may be considered as good indicators of environmental conditions and monitored in relation to changes in ecosystem structure due to climate change.

A new species of Moraria (Crustacea: Copepoda: Harpacticoida) from the Laurentian Great Lakes

USGS Publications Warehouse

Reid, Janet W.; Lesko, Lynn T.

2003-01-01

Moraria hudsoni n. sp. is described from Trails End Bay in Lake Michigan and Prentiss Bay in Lake Huron, Michigan, USA. The new species differs from its congeners in chaetotaxy, body ornamentation, and other characters. We review published records of members of Moraria from North and Central America; no species is known from South America. Species of this genus have been found in the mountains of southern Mexico, Guatemala, and Honduras, but none of these has been validly described. In North America, eight species have been recorded from Alaska, Canada, and the conterminous USA as far south as North Carolina. We report new geographical records of M. affinis from Virginia, and of both M. cristata and M. virginiana from Maryland and Virginia. We provide a tabular key to aid in identification of the named species of Moraria in North America.

Marine Flora and Fauna of the Northeastern United States. Copepoda: Lernaeopodidae and Sphyriidae.

ERIC Educational Resources Information Center

Ho, Ju-Shey

This report is part of a sub-series to aid biology students, biologists, biological oceanographers, and informed laymen in the identification and study of marine flora and fauna of the Northeastern United States. Contents of this report include: (1) Introduction; (2) Glossary; (3) Key to the marine lernaeopodoid copepods of the Northeastern United…

Genetic diversity patterns of microeukaryotic plankton communities in Shenhu Bay, southeast China

NASA Astrophysics Data System (ADS)

Zhang, Wenjing; Pan, Yongbo; Yu, Lingyu; Liu, Lemian

2017-06-01

Microeukaryotic plankton is an abundant and diverse component of marine environments and plays an important role in microbial food webs. However, few studies have been conducted on the genetic diversity of microeukaryotes in the subtropical bays of China. In the present study, we investigated the microeukaryotic plankton in the Shenhu Bay by using denaturing gradient gel electrophoresis (DGGE) and sequencing of prominent bands. Our results indicated that Copepoda and Dinophyceae were the most diverse groups, and that the microeukaryotic communities varied significantly between summer and autumn, with the autumn communities exhibited a higher diversity than summer communities. Furthermore, the community composition and diversity from both surface and bottom waters showed more significant differences in summer than in autumn. Environmental parameters also displayed obvious seasonal patterns. Redundancy analysis (RDA) showed that temperature was the most significant environmental factor shaping the seasonal patterns of the microplanktonic members in the Shenhu Bay. Community-level molecular techniques such as DGGE appear as useful tools to detect the presence of red tide causing species and to guide the management of coastal water mariculture.

Seasonal variation in the copepod community structure from a tropical Amazon estuary, Northern Brazil.

PubMed

Magalhães, André; Leite, Natália da R; Silva, João G S; Pereira, Luci C C; Costa, Rauquírio M da

2009-06-01

The main purpose of this study was to investigate the seasonal variation of copepod community structure during the months of July, September and November 2003 (dry season) and January, March and May 2004 (rainy season) in the Curuçá estuary, northern Brazil. Samples were collected during neap tides via gentle 200microm mesh net tows from a small powerboat. Measurements of surface water conductivity were accomplished in situ using an electronic conductivimeter and salinity was later obtained through the transformation of the conductivity values. Salinity varied seasonally from 7.2 +/- 0.1 to 39.2 +/- 1.8 (mean +/- standard deviation) and was influenced mainly by differences in the amount of rainfall between the studied sampling seasons. In total, 30 Copepoda taxa were identified and Acartia tonsa comprised the most representative species throughout the entire studied period followed by Acartia lilljeborgii, Subeucalanus pileatus and Paracalanus quasimodo. In the present study, the density values, ecological indexes and copepod species dominance presented a clear seasonal pattern, showing that the studied area may be considered seasonally heterogeneous in relation to the investigated parameters.

Zooplankton community resilience and aquatic environmental stability on aquaculture practices: a study using net cages.

PubMed

Dias, J D; Simões, N R; Bonecker, C C

2012-02-01

Fish farming in net cages causes changes in environmental conditions. We evaluated the resilience of zooplankton concerning this activity in Rosana Reservoir (Paranapanema River, PR-SP). Samples were taken near the net cages installed at distances upstream and downstream, before and after net cage installation. The resilience was estimated by the decrease in the groups' abundance after installing the net cages. The zooplankton community was represented by 106 species. The most abundant species were Synchaeta pectinata, S. oblonga, Conochilus coenobasis, Polyarthra dolichoptera and C. unicornis (Rotifera), Ceriodaphnia cornuta, Moina minuta, Bosmina hagmanni and C. silvestrii (Cladocera) and Notodiaptomus amazonicus (Copepoda). The resilience of microcrustaceans was affected in the growing points as this activity left the production environment for longer, delaying the natural ability of community responses. Microcrustaceans groups, mainly calanoid and cyclopoid copepods, had a different return rate. The net cage installation acted as a stress factor on the zooplankton community. Management strategies that cause fewer risks to the organisms and maximize energy flow may help in maintaining system stability.

Olfaction in a viscous environment: the "color" of sexual smells in Temora longicornis

NASA Astrophysics Data System (ADS)

Hinow, Peter; Strickler, J. Rudi; Yen, Jeannette

2017-06-01

We investigate chemical aspects of mating in the marine copepod Temora longicornis (Copepoda, Calanoidea). Our emphasis is the female pheromone signaling in form of well-defined trails for males to follow, observed in Doall et al. (Phil Trans R Soc Lond B 353:681-689, 1998). The viscous environment and the properties of the odorants play important roles as the spread of the pheromone trail limits the time during which it is useful for tracing. A key observation from our earlier work is the ability of a searching male to detect the direction of the female and to correct its swimming direction if necessary. We propose a simple mathematical model for the spread of a pheromone from a moving source and carry out numerical simulations of two possible detection mechanisms. We find that a searching agent that is capable to detect a ratio outperforms a searcher that depends on the gradient of a single compound. This suggests that copepod sex pheromones consist of blends of chemical compounds, and that a ratio detection mechanism similar to that in airborne insects is at work.

Lake Roosevelt Fisheries Evaluation Program, Part B; Limnology, Primary Production, and Zooplankton in Lake Roosevelt, Washington, 1998 Annual Report.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Shields, John; Spotts, Jim; Underwood, Keith

2002-11-01

depth of 1.5 m (5 ft) when compared with a 4.6 m (15 ft) depth, and during the shorter incubation periods (two and four weeks). Mean zooplankton densities were greatest for Copepoda (88 %), then Daphnia spp. (10%) and other Cladocera (2.1%), while the zooplankton biomass assessment indicated Daphnia spp. had the greatest biomass (53.6%), then Copepoda (44.0%) and other Cladocera (2.5%). Mean overall zooplankton densities were the lowest observed since 1991. The cause was unclear, but may have been an artifact of human error. It seems unlikely that hydro-operations played a significant part in the reduction of zooplankton in light of the relatively friendly water year of 1998.« less

Microbial community variation and functions to excess sludge reduction in a novel gravel contact oxidation reactor.

PubMed

Lin, Shanshan; Jin, Y; Fu, L; Quan, C; Yang, Y S

2009-06-15

. per 20 ml) and in ASR (15 no. per 20 ml); the next abundant group was attachment plants 10 no. per 20 ml in GCOR and 4 no. per 20 ml in ASR, respectively. Rotifers and copepoda belonging to metazoan were only present in GCOR (8 no. per 20 ml for both rotifers and copepoda). The microbial diversity and population difference both in the GCOR carriers and ASR sludge indicated that the diverse microbes, a large amount of biomass forming longer microbial food chains attached on the carriers may be the main functions for the excess sludge reduction in GCOR.

Allee effects may slow the spread of parasites in a coastal marine ecosystem.

PubMed

Krkošek, Martin; Connors, Brendan M; Lewis, Mark A; Poulin, Robert

2012-03-01

Allee effects are thought to mediate the dynamics of population colonization, particularly for invasive species. However, Allee effects acting on parasites have rarely been considered in the analogous process of infectious disease establishment and spread. We studied the colonization of uninfected wild juvenile Pacific salmon populations by ectoparasitic salmon lice (Lepeophtheirus salmonis) over a 4-year period. In a data set of 68,376 fish, we observed 85 occurrences of precopular pair formation among 1,259 preadult female and 613 adult male lice. The probability of pair formation was dependent on the local abundance of lice, but this mate limitation is likely offset somewhat by mate-searching dispersal of males among host fish. A mathematical model of macroparasite population dynamics that incorporates the empirical results suggests a high likelihood of a demographic Allee effect, which can cause the colonizing parasite populations to die out. These results may provide the first empirical evidence for Allee effects in a macroparasite. Furthermore, the data give a rare detailed view of Allee effects in colonization dynamics and suggest that Allee effects may dampen the spread of parasites in a coastal marine ecosystem.

A comparison of neutral and immune genetic variation in Atlantic salmon, Salmo salar L. in Chilean aquaculture facilities.

PubMed

Portnoy, David S; Hollenbeck, Christopher M; Vidal, R Rodrigo; Gold, John R

2014-01-01

Genetic diversity was assessed in samples of cultured Atlantic salmon, Salmo salar L., obtained from facilities in Chile between 2005 and 2010, a period of time during which the infectious pathogens Infectious Salmon Anemia (ISA) virus, Caligus rogercresseyi (sea lice), and Piscirickettsia salmonis (salmon rickettsial syndrome) were common. Two panels of microsatellite markers were utilized: one with microsatellites with no known gene associations (neutral) and one featuring microsatellites linked to putative immune-related genes (immune-related). Allelic richness and gene diversity across samples were significantly greater in neutral loci as compared to immune-related loci. Both diversity measures were homogeneous among samples for immune-related loci and heterogeneous among samples for neutral loci. Immune-related loci were identified as F(ST) outliers in pairwise comparisons of samples at a 10-fold higher frequency than neutral loci. These results indicate that neutral and immune-related portions of the Atlantic salmon genome may have differed in response to the gauntlet of pathogens and that monitoring of specific, well characterized immune-related loci as well as neutral loci in cultured species could be useful when disease control and prevention is a goal.

A survey of wild marine fish identifies a potential origin of an outbreak of viral haemorrhagic septicaemia in wrasse, Labridae, used as cleaner fish on marine Atlantic salmon, Salmo salar L., farms.

PubMed

Wallace, I S; Donald, K; Munro, L A; Murray, W; Pert, C C; Stagg, H; Hall, M; Bain, N

2015-06-01

Viral haemorrhagic septicaemia virus (VHSV) was isolated from five species of wrasse (Labridae) used as biological controls for parasitic sea lice predominantly, Lepeophtheirus salmonis (Krøyer, 1837), on marine Atlantic salmon, Salmo salar L., farms in Shetland. As part of the epidemiological investigation, 1400 wild marine fish were caught and screened in pools of 10 for VHSV using virus isolation. Eleven pools (8%) were confirmed VHSV positive from: grey gurnard, Eutrigla gurnardus L.; Atlantic herring, Clupea harengus L.; Norway pout, Trisopterus esmarkii (Nilsson); plaice, Pleuronectes platessa L.; sprat, Sprattus sprattus L. and whiting, Merlangius merlangus L. The isolation of VHSV from grey gurnard is the first documented report in this species. Nucleic acid sequencing of the partial nucleocapsid (N) and glycoprotein (G) genes was carried out for viral characterization. Sequence analysis confirmed that all wild isolates were genotype III the same as the wrasse and there was a close genetic similarity between the isolates from wild fish and wrasse on the farms. Infection from these local wild marine fish is the most likely source of VHSV isolated from wrasse on the fish farms. © 2014 Crown Copyright. Journal of Fish Diseases © 2014 John Wiley & Sons Ltd.

Rapid Identification of Seven Waterborne Exophiala Species by RCA DNA Padlock Probes.

PubMed

Najafzadeh, M J; Vicente, V A; Feng, Peiying; Naseri, A; Sun, Jiufeng; Rezaei-Matehkolaei, A; de Hoog, G S

2018-03-05

The black yeast genus Exophiala includes numerous potential opportunistic species that potentially cause systematic and disseminated infections in immunocompetent individuals. Species causing systemic disease have ability to grow at 37-40 °C, while others consistently lack thermotolerance and are involved in diseases of cold-blooded, waterborne vertebrates and occasionally invertebrates. We explain a fast and sensitive assay for recognition and identification of waterborne Exophiala species without sequencing. The ITS rDNA region of seven Exophiala species (E. equina, E. salmonis, E. opportunistica, E. pisciphila, E. aquamarina, E. angulospora and E. castellanii) along with the close relative Veronaea botryosa was sequenced and aligned for the design of specific padlock probes for the detection of characteristic single-nucleotide polymorphisms. The assay demonstrated to successfully amplify DNA of target fungi, allowing detection at the species level. Amplification products were visualized on 1% agarose gels to confirm specificity of probe-template binding. Amounts of reagents were reduced to prevent the generation of false positive results. The simplicity, tenderness, robustness and low expenses provide padlock probe assay (RCA) a definite place as a very practical method among isothermal approaches for DNA diagnostics.

A Comparison of Neutral and Immune Genetic Variation in Atlantic Salmon, Salmo salar L. in Chilean Aquaculture Facilities

PubMed Central

Portnoy, David S.; Hollenbeck, Christopher M.; Vidal, R. Rodrigo; Gold, John R.

2014-01-01

Genetic diversity was assessed in samples of cultured Atlantic salmon, Salmo salar L., obtained from facilities in Chile between 2005 and 2010, a period of time during which the infectious pathogens Infectious Salmon Anemia (ISA) virus, Caligus rogercresseyi (sea lice), and Piscirickettsia salmonis (salmon rickettsial syndrome) were common. Two panels of microsatellite markers were utilized: one with microsatellites with no known gene associations (neutral) and one featuring microsatellites linked to putative immune-related genes (immune-related). Allelic richness and gene diversity across samples were significantly greater in neutral loci as compared to immune-related loci. Both diversity measures were homogeneous among samples for immune-related loci and heterogeneous among samples for neutral loci. Immune-related loci were identified as FST outliers in pairwise comparisons of samples at a 10-fold higher frequency than neutral loci. These results indicate that neutral and immune-related portions of the Atlantic salmon genome may have differed in response to the gauntlet of pathogens and that monitoring of specific, well characterized immune-related loci as well as neutral loci in cultured species could be useful when disease control and prevention is a goal. PMID:24918941

Infestation and Pathological Alterations by Ergasilus sarsi (Copepoda) on the Tanganyika Killifish from Africa

PubMed Central

Kilian, Esmari; Avenant-Oldewage, Annemariè

2013-01-01

A total of 204 Ergasilus sarsi, a copepod, were collected from Tanganyika Killifish Lamprichthys tanganicanus in Lake Tanganyika during March 2010. The prevalence was 86.40%, the mean intensity was 7.56, and the mean abundance was 6.38. Only 27 of the fish were infested, and the highest infestation on one fish was 29. Proliferation of mucus cells and lamellar fusion occurred. Haemorrhage due to blood vessel compression was noted. This is the first record of E. sarsi from Tanganyika Killifish. This study is also the first to provide a description of the pathological alterations caused by E. sarsi. PMID:24341764

Molecular phylogeny of Oncaeidae (Copepoda) using nuclear ribosomal internal transcribed spacer (ITS rDNA)

PubMed Central

Di Capua, Iole; Maffucci, Fulvio; Pannone, Raimondo; Mazzocchi, Maria Grazia

2017-01-01

Copepods belonging to the Oncaeidae family are commonly and abundantly found in marine zooplankton. In the Mediterranean Sea, forty-seven oncaeid species occur, of which eleven in the Gulf of Naples. In this Gulf, several Oncaea species were morphologically analysed and described at the end of the XIX century by W. Giesbrecht. In the same area, oncaeids are being investigated over seasonal and inter-annual scales at the long-term coastal station LTER-MC. In the present work, we identified six oncaeid species using the nuclear ribosomal internal transcribed spacers (ITS rDNA) and the mitochondrial cytochrome c oxidase subunit I (mtCOI). Phylogenetic analyses based on these two genomic regions validated the sisterhood of the genera Triconia and the Oncaea sensu stricto. ITS1 and ITS2 phylogenies produced incongruent results about the position of Oncaea curta, calling for further investigations on this species. We also characterised the ITS2 region by secondary structure predictions and found that all the sequences analysed presented the distinct eukaryotic hallmarks. A Compensatory Base Change search corroborated the close relationship between O. venusta and O. curta and between O. media and O. venusta already identified by ITS phylogenies. The present results, which stem from the integration of molecular and morphological taxonomy, represent an encouraging step towards an improved knowledge of copepod biodiversity: The two complementary approaches, when applied to long-term copepod monitoring, will also help to better understanding their genetic variations and ecological niches of co-occurring species. PMID:28441395

GFP-like proteins as ubiquitous metazoan superfamily: evolution of functional features and structural complexity.

PubMed

Shagin, Dmitry A; Barsova, Ekaterina V; Yanushevich, Yurii G; Fradkov, Arkady F; Lukyanov, Konstantin A; Labas, Yulii A; Semenova, Tatiana N; Ugalde, Juan A; Meyers, Ann; Nunez, Jose M; Widder, Edith A; Lukyanov, Sergey A; Matz, Mikhail V

2004-05-01

Homologs of the green fluorescent protein (GFP), including the recently described GFP-like domains of certain extracellular matrix proteins in Bilaterian organisms, are remarkably similar at the protein structure level, yet they often perform totally unrelated functions, thereby warranting recognition as a superfamily. Here we describe diverse GFP-like proteins from previously undersampled and completely new sources, including hydromedusae and planktonic Copepoda. In hydromedusae, yellow and nonfluorescent purple proteins were found in addition to greens. Notably, the new yellow protein seems to follow exactly the same structural solution to achieving the yellow color of fluorescence as YFP, an engineered yellow-emitting mutant variant of GFP. The addition of these new sequences made it possible to resolve deep-level phylogenetic relationships within the superfamily. Fluorescence (most likely green) must have already existed in the common ancestor of Cnidaria and Bilateria, and therefore GFP-like proteins may be responsible for fluorescence and/or coloration in virtually any animal. At least 15 color diversification events can be inferred following the maximum parsimony principle in Cnidaria. Origination of red fluorescence and nonfluorescent purple-blue colors on several independent occasions provides a remarkable example of convergent evolution of complex features at the molecular level.

Meiobenthos assemblages in the mekong estuarine system with special focus on free-living marine nematodes

NASA Astrophysics Data System (ADS)

Quang, Ngo Xuan; Vanreusel, Ann; Smol, Nic; Chau, Nguyen Ngoc

2010-12-01

Meiobenthos assemblages in eight estuaries of the Mekong river system were investigated in August 2008 (from the Cua Tieu estuary to the Tran De estuary). In each estuary, one sampling station was established for meiobenthos sampling. Twelve major taxa of meiobenthos were recorded in this estuarine system, including Nematoda, Copepoda, Turbellaria, Polychaeta, Oligochaeta, Tardigrada, Bivalvia, Ostracoda, Amphipoda, Cumacea, Gastrotricha, Gastropoda, and Crustacean Nauplii larvae. The densities of the meiobenthos range from 581 to 3168 inds/10 cm2. Nematodes always occupy the highest numbers with a percentage ranging from 64-99%. There are 135 nematode genera recorded in this study with the following as dominant genera Desmodora, Leptolaimus, Halalaimus, Thalassomonhystera, Theristus, Daptonema, Rhynchonema, Parodontophora, and Oncholaimus. Although the biodiversity of the meiobenthos at higher taxa level is not high compared to other marine environments, the estimates of nematode biodiversity at the genus level indicates high values. The increase in number of genera with increasing sampling intensity illustrate that the diversity is underestimated and would have been higher if the authors had considered a larger number of individuals, more replicates per station, and more sampling stations.

Marine netpen farming leads to infections with some unusual parasites.

PubMed

Kent, M L

2000-03-01

Marine netpen farming of salmonid fishes is a rapidly growing industry in several countries. With this relatively recent industry, new or unusual infections by parasitic pathogens have been observed. This is due to different hosts being reared in new geographic areas, or by indigenous species being reared in a different environmental condition, i.e. the marine netpen. Examples of the former include Kudoa thyrsites (Myxozoa) and Hemobaphes disphaerocephalus (Copepoda) infections in Atlantic salmon (Salmo salar) reared in the Pacific Northwest, Ceratothoa gaudichaudii (Isopoda) infections in Atlantic salmon reared in Chile, Neoparamoeba (=Paramoeba) sp. (Sacromastigophora) from salmonids reared in Tasmania, and Stephanostomum tenue (Digenea) infections in rainbow trout (Oncorhynchus mykiss) reared in Atlantic Canada. Chinook salmon (Oncorhynchus tshawytscha) reared in its native region, the Pacific Northwest, provides some examples of unusual or more severe infections than those normally seen in wild or freshwater reared chinook salmon. These include infections by Loma salmonae (Microsporidia), Gilguina squali (Cestoda) and the rosette agent, an undescribed fungus-like organism related to choanoflagellates. As the industry continues to expand, it is certain that more novel host-parasite relationships will be observed, providing challenges for fish farmers and parasitologists.

Human-mediated dispersal of aquatic invertebrates with waterproof footwear.

PubMed

Valls, Luis; Castillo-Escrivà, Andreu; Mesquita-Joanes, Francesc; Armengol, Xavier

2016-02-01

Human-mediated dispersal has rarely been considered in wetland conservation strategies at regional scales, yet high concern exists about this aspect for (inter-)national management considering invasive species in other aquatic systems. In this context, we aim at understanding the role of human-mediated dispersal by footwear in protected wetlands with high conservation value. Zooplankton and zoobenthos were sampled in 13 shallow lakes in central Spain and, at the same time, mud attached to waders was collected and later cultured in deionized water under laboratory conditions for 4 weeks. Two-hundred and four individuals belonging to 19 invertebrate taxa were recovered after hatching; Ostracoda (84 %), Cladocera (53 %), Copepoda (30 %), Anostraca (30 %), and Notostraca (7 %) were the most frequent groups among the hatched crustaceans. NMDS and PERMANOVA analyses showed significant differences between the dispersed (via footwear) and the source active metacommunity, suggesting different dispersal abilities among the species found. Human vectors facilitate dispersal among protected lakes, which could eventuality lead to biotic homogenization and faster spread of non-indigenous species. Preservation strategies and education campaigns associated to target humans in close contact with water bodies should be imperative in conservation management of protected lakes.

Species Composition and Distribution of Zooplankton from Northeastern Sakhalin Shelf (Sea of Okhotsk)

NASA Astrophysics Data System (ADS)

Kasyan, V. V.

2018-03-01

The species composition, density, biomass, and distribution of zooplankton of the northeastern Sakhalin shelf, Sea of Okhotsk (Chaivo, Pil'tunskii, and Morskoi regions) were studied in October 2014. Zooplankton was represented by 15 taxonomic groups, which were dominated by Copepoda (13 species). The average density and biomass was highest in the Chaivo region (14112 ± 4322 ind./m3, 395 ± 107 mg/m3) and in the Pil'tunskii region (16692 ± 10707 ind./m3, 346 ± 233 mg/m3); the abundance of detected taxonomic groups was minimal (8-12). The average density and biomass of zooplankton was up to 4304 ± 2441 ind./m3, 133 ± 77 mg/m3 in the Morskoi region and increased with depth; the abundance of taxa was maximum (15). Four species of copepods made up the majority of the density and biomass of zooplankton: Acartia hudsonica, Eurytemora herdmani, Pseudocalanus newmani, and Oithona similis. In the Chaivo region, species of the genera Acartia, Eurytemora, and Oithona dominated and subdominated; in Pil'tunskii region, species of the genera Acartia and Oithona dominated and subdominated; and in the Morskoi region, species of the genera Oithona, Pseudocalanus, and Acartia dominated and subdominated.

Very Bright Green Fluorescent Proteins from the Pontellid Copepod Pontella mimocerami

PubMed Central

Hunt, Marguerite E.; Scherrer, Michael P.; Ferrari, Frank D.; Matz, Mikhail V.

2010-01-01

Background Fluorescent proteins (FP) homologous to the green fluorescent protein (GFP) from the jellyfish Aequorea victoria have revolutionized biomedical research due to their usefulness as genetically encoded fluorescent labels. Fluorescent proteins from copepods are particularly promising due to their high brightness and rapid fluorescence development. Results Here we report two novel FPs from Pontella mimocerami (Copepoda, Calanoida, Pontellidae), which were identified via fluorescence screening of a bacterial cDNA expression library prepared from the whole-body total RNA of the animal. The proteins are very similar in sequence and spectroscopic properties. They possess high molar extinction coefficients (79,000 M−1 cm−) and quantum yields (0.92), which make them more than two-fold brighter than the most common FP marker, EGFP. Both proteins form oligomers, which we were able to counteract to some extent by mutagenesis of the N-terminal region; however, this particular modification resulted in substantial drop in brightness. Conclusions The spectroscopic characteristics of the two P. mimocerami proteins place them among the brightest green FPs ever described. These proteins may therefore become valuable additions to the in vivo imaging toolkit. PMID:20644720

Composition, abundance and distribution of macrozooplankton in Culebra Bay, Gulf of Papagayo, Pacific coast of Costa Rica and its value as bioindicator of pollution.

PubMed

Bednarski, Melinda; Morales-Ramírez, Alvaro

2004-12-01

The abundance, distribution and composition of the macrozooplankton of Culebra Bay, Costa Rica (10 degrees 38' N - 85 degrees 40' W) were studied at four stations throughout the dry (February-May) and rainy (September-November) seasons of 2000. The samples were collected at two-week intervals using a 500 microm mesh net with a 0.5 m diameter opening. Copepods (23-31%) and ostracods (20-34%) were predominant throughout the year, followed by cladocerans (2.5-14%), zoea (6.6-9.5%), and siphonophores (2.5-7.2%). High densities of zooplankton were obtained in February and March with peak abundance on March 18. The lowest densities were observed on September 3 and November 5. Significant differences in abundances at each station were observed for the groups Acartia tonsa (Copepoda), Ctenophora, Medusae, Ostracoda, Zoea, and Amphipoda. Comparison of the dry and rainy seasons revealed significantly higher zooplankton abundance in the dry season and copepod domination of all stations; during the rainy season ostracods dominated the off-shore areas. Zooplankton abundance and distribution are influenced by upwelling, which occurs during the dry season in Culebra Bay.

UV radiation and freshwater zooplankton: damage, protection and recovery

PubMed Central

Rautio, Milla; Tartarotti, Barbara

2011-01-01

While many laboratory and field studies show that zooplankton are negatively affected when exposed to high intensities of ultraviolet radiation (UVR), most studies also indicate that zooplankton are well adapted to cope with large variations in their UVR exposure in the pelagic zone of lakes. The response mechanisms of zooplankton are diverse and efficient and may explain the success and richness of freshwater zooplankton in optically variable waters. While no single behavioural or physiological protection mechanism seems to be superior, and while several unexplained and contradictory patterns exist in zooplankton UVR ecology, recent increases in our understanding are consistent with UVR playing an important role for zooplankton. This review examines the variability in freshwater zooplankton responses to UVR, with a focus on crustacean zooplankton (Cladocera and Copepoda). We present an overview of UVR-induced damages, and the protection and recovery mechanisms freshwater zooplankton use when exposed to UVR. We review the current knowledge of UVR impact on freshwater zooplankton at species and community levels, and discuss briefly how global change over the last three decades has influenced the UVR milieu in lakes. PMID:21516254

Two new species of the genus Monstrillopsis Sars, 1921 (Copepoda: Monstrilloida: Monstrillidae) from South Korea.

PubMed

Lee, Jimin; Kim, Dongsung; Chang, Cheon Young

2016-10-11

Monstrilloid copepods of the genus Monstrillopsis Sars, 1921 are recorded from Korea, as well as from the northwestern Pacific, for the first time. Specimens were obtained using a light trap set overnight at piers or seawalls in small harbors. Males of two new species were found and are described herein with remarks on their affinities and detailed drawings and SEM photographs of their morphological features. Monstrillopsis longilobata sp. nov. is allied to M. chathamensis Suárez-Morales & Morales-Ramírez, 2009 and M. sarsi Isaac, 1974 in having the character combination of a long, claw-like apical spinous process on the male antennule and elongate genital lappets. It differs from them in having conspicuous transverse striations on the dorsal surface of the cephalothorax and extremely long male genital lappets, which extend far beyond the anterior margins of the caudal rami. Monstrillopsis coreensis sp. nov. also has a claw-like apical spinous process of the male antennule and conspicuous transverse striations on the dorsal surface of the cephalothorax, but it differs from M. longilobata in having a much longer and stronger apical spine of the antennule and a relatively shorter and undulating genital apparatus.

Effect of diurnal temperature difference on lipid accumulation and development in Calanus sinicus (Copepoda: Calanoida)

NASA Astrophysics Data System (ADS)

Zhou, Konglin; Sun, Song

2017-07-01

Calanus sinicus, the dominant copepod in the Yellow Sea, develops a large oil sac in late spring to prepare for over-summering in the Yellow Sea Cold Water Mass (YSCWM). The lipid accumulation mechanism for the initiation of over-summering is unknown. Here, we cultured C3 copepodites at four constant temperatures (10, 13, 16, and 19°C) and at three temperature regimes that mimicked the temperature variations experienced during diurnal vertical migration (10-13°C, 10-16°C, and 10-19°C) for 18 days to explore the effects of temperature differences on copepod development and lipid accumulation. C. sinicus stored more lipid at low than at high temperatures. A diurnal temperature difference (10-16°C and 10-19°C) promoted greater lipid accumulation (1.9-2.1 times) than a constant temperature of either 16°C or 19°C, by reducing the energy cost at colder temperatures and lengthening copepodite development. Thereafter, the lipid reserve supported gonad development after final molting. Only one male developed in these experiments. This highly female-skewed sex ratio may have been the result of the monotonous microalgae diet fed to the copepodites. This study provides the first evidence that diurnal temperature differences may promote lipid accumulation in C. sinicus, and provides a foundation for future investigations into the mechanisms involved in over-summering in the YSCWM.

Reproduction of Pseudocalanus newmani (Copepoda: Calanoida) is deleteriously affected by diatom blooms A field study

NASA Astrophysics Data System (ADS)

Halsband-Lenk, Claudia; Pierson, James J.; Leising, Andrew W.

2005-11-01

Copepod secondary production has traditionally been linked to the spring diatom bloom in temperate and high latitudes, but laboratory studies have recently challenged this view and have shown either reduced fecundity or viability of offspring when copepods were fed high concentrations of - mostly unialgal - diatoms. However, field evidence that diatoms affect copepod reproduction is still scarce. We analyzed the reproductive response of a common, small calanoid copepod of the boreal Pacific, Pseudocalanus newmani, to spring diatom blooms in Dabob Bay, a semi-enclosed fjord of Puget Sound, Washington, USA. Abundance patterns, egg production rates, egg hatching success, and naupliar viability of the egg-carrying copepod were examined between February and early May in the years 2002-2004. The population underwent strong variations in abundance during both years, with high abundance of all stages from February to mid-March, but dramatically decreasing individual numbers later in spring. A recovery to higher numbers occurred in July. While egg production rates were independent of chlorophyll concentrations, the reproductive success of P. newmani was negatively affected by certain phytoplankton bloom conditions. Hatching success and - more markedly - naupliar survival were reduced following peaks of Thalassiosira species that were producing anti-mitotic aldehydes, but were high during periods when phytoplankton blooms were more diverse or dominated by other prey taxa including diatoms. As a consequence, recruitment of the naupliar population was considerably affected by the Thalassiosira blooms. This study shows for the first time that the so-called diatom effect operates in nature when all prerequisites - (1) high concentration of aldehyde producers, (2) few prey alternatives, and (3) feeding of copepods on these algae - are given. However, the effect was transient in Dabob Bay and may be so in other pelagic ecosystems. It remains to discern the potential sources of mortality, such as toxicity, malnutrition, predation, and/or advection, that may have caused the strong decline of the Pseudocalanus population during April.

Genetic and morphological heterogeneity among populations of Eurytemora affinis (Crustacea: Copepoda: Temoridae) in European waters.

PubMed

Sukhikh, Natalia; Souissi, Anissa; Souissi, Sami; Winkler, Gesche; Castric, Vincent; Holl, Anne-Catherine; Alekseev, Victor

2016-01-01

Our understanding of the systematics of the Eurytemora affinis complex developed at a fast pace over the last decades. Formerly considered as a complex of cryptic species, it is now believed to include three valid species: E. affinis, Eurytemora carolleeae, and Eurytemora caspica. American and European representatives have been studied in detail with respect to fine-scale geographic distribution, levels of genetic subdivision, evolutionary and demographic histories. Morphological components have been less explored. In this study, an analysis of the phylogeny and morphology of E. affinis was done, with a special focus on European populations. A total of 447 individuals of E. affinis from Europe were analyzed with genetic tools and 170 individuals according to morphological criteria. Common and new morphological and genetic features were analyzed. For this, we used ML and Bayesian methods to analyze the bar coding mt-DNA gene cytochrome c oxidase I subunit. Both genetic and morphological analyses showed high heterogeneities among the E. affinis populations from Europe. As a result, three local populations of E. affinis in Western Europe, including the European part of Russia, were established. Their genetic and morphological heterogeneity corresponded to the subspecies level. Copyright © 2016 Académie des sciences. Published by Elsevier SAS. All rights reserved.

Macrocyclops albidus (Copepoda: cyclopidae) for the Biocontrol of Aedes albopictus and Culex pipiens in Italy.

PubMed

Veronesi, Rodolfo; Carrieri, Marco; Maccagnani, Bettina; Maini, Stefano; Bellini, Romeo

2015-03-01

The aim of our study was to assess the potential of Macrocyclops albidus as a biological control agent against the 1st and 2nd instars of Culex pipiens and Aedes albopictus. Under laboratory conditions of prey saturation (50 1st instars/copepod), an average of 58.98% of Cx. pipiens and 54.99% of Ae. albopictus larvae were killed by 1 copepod in 24 h. Trials run in big drums containing 200 liters of water showed that the M. albidus population, inoculated in April, efficiently controlled the mosquito population for the entire season. The predator was particularly effective against Ae. albopictus, as only 2 larvae of this species were found in the treated drums, compared to 814 larvae in untreated control drums throughout the study period. No difference was observed in the control efficacy between the 2 initial densities of copepods used. The reduction in Ae. albopictus density in the drums with 100 and 500 M. albidus with respect to the control drums was 99.90 ± 0.35% and 100.0 ± 0.0%, respectively. For Cx. pipiens, the reduction in density was 88.69 ± 13.51% and 84.65% in drums inoculated with 100 and 500 copepods, respectively. Macrocyclops albidus populations survived through the winter and continued to keep the mosquito population under control during the 2008 season. The M. albidus population developed very well both in drums placed in sunny and shaded areas and proved to be tolerant to both high (summer) and low (winter) temperatures. Trials performed on M. albidus survival in catch basins showed that after a few weeks, the copepod population dramatically decreased and subsequently disappeared. The main problem for copepod survival in catch basins seemed to be the low oxygen tension and accumulation of toxic substances, rather than copepods being flushed out in heavy rainfall episodes. During the period when copepods were present, they maintained the mosquito population under control; their partial disappearance from the catch basins, however, would require more recolonization intervention to maintain mosquito control during the season.

Copepods of Hatschekiidae (Copepoda, Siphonostomatoida) new to Korean fauna, with description of a new species

NASA Astrophysics Data System (ADS)

Moon, Seong Yong; Kim, Il-Hoi

2013-03-01

Eight species of the Hatschekiidae are recorded as parasites of marine fishes from southern coast of Korea. One new species, Hatschekia jejuensis, parasitic on Cheilodactylus zonatus Cuvier is included. The remaining seven species are new to Korean fauna: Hatschekia iridescens Wilson, 1913, H. japonica Jones, 1985, H. monacanthi Yamaguti, 1939, H. tenuis (Heller, 1865) H. pseudolabri Yamaguti, 1953, H. cylindrica Shiino, 1957, and Pseudocongericola chefoonensis Yü, 1933. Hatschekia jejuensis n. sp. has a combination of characteristics in the female where the trunk is 2.35 times as long as the cephalothorax and displays a pair of posterolateral bulges on both sides, the antennules is 5-segmented, the mandible bears six teeth, and the armature formulae of the legs are I-0; III (exopod) and 0-0; II (endopod) for leg 1 and I-0; I (exopod) and 0-0; II (endopod) for leg 2.

Modeling Parasite Dynamics on Farmed Salmon for Precautionary Conservation Management of Wild Salmon

PubMed Central

Rogers, Luke A.; Peacock, Stephanie J.; McKenzie, Peter; DeDominicis, Sharon; Jones, Simon R. M.; Chandler, Peter; Foreman, Michael G. G.; Revie, Crawford W.; Krkošek, Martin

2013-01-01

Conservation management of wild fish may include fish health management in sympatric populations of domesticated fish in aquaculture. We developed a mathematical model for the population dynamics of parasitic sea lice (Lepeophtheirus salmonis) on domesticated populations of Atlantic salmon (Salmo salar) in the Broughton Archipelago region of British Columbia. The model was fit to a seven-year dataset of monthly sea louse counts on farms in the area to estimate population growth rates in relation to abiotic factors (temperature and salinity), local host density (measured as cohort surface area), and the use of a parasiticide, emamectin benzoate, on farms. We then used the model to evaluate management scenarios in relation to policy guidelines that seek to keep motile louse abundance below an average three per farmed salmon during the March–June juvenile wild Pacific salmon (Oncorhynchus spp.) migration. Abiotic factors mediated the duration of effectiveness of parasiticide treatments, and results suggest treatment of farmed salmon conducted in January or early February minimized average louse abundance per farmed salmon during the juvenile wild salmon migration. Adapting the management of parasites on farmed salmon according to migrations of wild salmon may therefore provide a precautionary approach to conserving wild salmon populations in salmon farming regions. PMID:23577082

Cessation of a salmon decline with control of parasites.

PubMed

Peacock, Stephanie J; Krkosek, Martin; Proboszcz, Stan; Orr, Craig; Lewis, Mark A

2013-04-01

The resilience of coastal social-ecological systems may depend on adaptive responses to aquaculture disease outbreaks that can threaten wild and farm fish. A nine-year study of parasitic sea lice (Lepeophtheirus salmonis) and pink salmon (Oncorhynchus gorbuscha) from Pacific Canada indicates that adaptive changes in parasite management on salmon farms have yielded positive conservation outcomes. After four years of sea lice epizootics and wild salmon population decline, parasiticide application on salmon farms was adapted to the timing of wild salmon migrations. Winter treatment of farm fish with parasiticides, prior to the out-migration of wild juvenile salmon, has reduced epizootics of wild salmon without significantly increasing the annual number of treatments. Levels of parasites on wild juvenile salmon significantly influence the growth rate of affected salmon populations, suggesting that these changes in management have had positive outcomes for wild salmon populations. These adaptive changes have not occurred through formal adaptive management, but rather, through multi-stakeholder processes arising from a contentious scientific and public debate. Despite the apparent success of parasite control on salmon farms in the study region, there remain concerns about the long-term sustainability of this approach because of the unknown ecological effects of parasticides and the potential for parasite resistance to chemical treatments.

Sea lice and salmon population dynamics: effects of exposure time for migratory fish.

PubMed

Krkosek, Martin; Morton, Alexandra; Volpe, John P; Lewis, Mark A

2009-08-07

The ecological impact of parasite transmission from fish farms is probably mediated by the migration of wild fishes, which determines the period of exposure to parasites. For Pacific salmon and the parasitic sea louse, Lepeophtheirus salmonis, analysis of the exposure period may resolve conflicting observations of epizootic mortality in field studies and parasite rejection in experiments. This is because exposure periods can differ by 2-3 orders of magnitude, ranging from months in the field to hours in experiments. We developed a mathematical model of salmon-louse population dynamics, parametrized by a study that monitored naturally infected juvenile salmon held in ocean enclosures. Analysis of replicated trials indicates that lice suffer high mortality, particularly during pre-adult stages. The model suggests louse populations rapidly decline following brief exposure of juvenile salmon, similar to laboratory study designs and data. However, when the exposure period lasts for several weeks, as occurs when juvenile salmon migrate past salmon farms, the model predicts that lice accumulate to abundances that can elevate salmon mortality and depress salmon populations. The duration of parasite exposure is probably critical to salmon-louse population dynamics, and should therefore be accommodated in coastal planning and management where fish farms are situated on wild fish migration routes.

Transmission dynamics of parasitic sea lice from farm to wild salmon.

PubMed

Krkosek, Martin; Lewis, Mark A; Volpe, John P

2005-04-07

Marine salmon farming has been correlated with parasitic sea lice infestations and concurrent declines of wild salmonids. Here, we report a quantitative analysis of how a single salmon farm altered the natural transmission dynamics of sea lice to juvenile Pacific salmon. We studied infections of sea lice (Lepeophtheirus salmonis and Caligus clemensi) on juvenile pink salmon (Oncorhynchus gorbuscha) and chum salmon (Oncorhynchus keta) as they passed an isolated salmon farm during their seaward migration down two long and narrow corridors. Our calculations suggest the infection pressure imposed by the farm was four orders of magnitude greater than ambient levels, resulting in a maximum infection pressure near the farm that was 73 times greater than ambient levels and exceeded ambient levels for 30 km along the two wild salmon migration corridors. The farm-produced cohort of lice parasitizing the wild juvenile hosts reached reproductive maturity and produced a second generation of lice that re-infected the juvenile salmon. This raises the infection pressure from the farm by an additional order of magnitude, with a composite infection pressure that exceeds ambient levels for 75 km of the two migration routes. Amplified sea lice infestations due to salmon farms are a potential limiting factor to wild salmonid conservation.

Using Agent-Based Modelling to Predict the Role of Wild Refugia in the Evolution of Resistance of Sea Lice to Chemotherapeutants.

PubMed

McEwan, Gregor F; Groner, Maya L; Fast, Mark D; Gettinby, George; Revie, Crawford W

2015-01-01

A major challenge for Atlantic salmon farming in the northern hemisphere is infestation by the sea louse parasite Lepeophtheirus salmonis. The most frequent method of controlling these sea louse infestations is through the use of chemical treatments. However, most major salmon farming areas have observed resistance to common chemotherapeutants. In terrestrial environments, many strategies employed to manage the evolution of resistance involve the use of refugia, where a portion of the population is left untreated to maintain susceptibility. While refugia have not been deliberately used in Atlantic salmon farming, wild salmon populations that migrate close to salmon farms may act as natural refugia. In this paper we describe an agent-based model that explores the influence of different sizes of wild salmon populations on resistance evolution in sea lice on a salmon farm. Using the model, we demonstrate that wild salmon populations can act as refugia that limit the evolution of resistance in the sea louse populations. Additionally, we demonstrate that an increase in the size of the population of wild salmon results in an increased effect in slowing the evolution of resistance. We explore the effect of a population fitness cost associated with resistance, finding that in some cases it substantially reduces the speed of evolution to chemical treatments.

Managing aquatic parasites for reduced drug resistance: lessons from the land.

PubMed

McEwan, Gregor F; Groner, Maya L; Burnett, Danielle L; Fast, Mark D; Revie, Crawford W

2016-12-01

Atlantic salmon farming is one of the largest aquaculture industries in the world. A major problem in salmon farms is the sea louse ectoparasite Lepeophtheirus salmonis, which can cause stress, secondary infection and sometimes mortality in the salmon host. Sea lice have substantial impacts on farm economics and potentially nearby wild salmonid populations. The most common method of controlling sea louse infestations is application of chemicals. However, most farming regions worldwide have observed resistance to the small set of treatment chemicals that are available. Despite this, there has been little investigation of treatment strategies for managing resistance in aquaculture. In this article, we compare four archetypical treatment strategies inspired by agriculture, where the topic has a rich history of study, and add a fifth strategy common in aquaculture. We use an agent-based model (ABM) to simulate these strategies and their varying applications of chemicals over time and space. We analyse the ABM output to compare how the strategies perform in controlling louse abundance, number of treatments required and levels of resistance in the sea louse population. Our results indicated that among the approaches considered applying chemicals in combination was the most effective over the long term. © 2016 The Author(s).

Impact of parasites on salmon recruitment in the Northeast Atlantic Ocean

PubMed Central

Krkošek, Martin; Revie, Crawford W.; Gargan, Patrick G.; Skilbrei, Ove T.; Finstad, Bengt; Todd, Christopher D.

2013-01-01

Parasites may have large effects on host population dynamics, marine fisheries and conservation, but a clear elucidation of their impact is limited by a lack of ecosystem-scale experimental data. We conducted a meta-analysis of replicated manipulative field experiments concerning the influence of parasitism by crustaceans on the marine survival of Atlantic salmon (Salmo salar L.). The data include 24 trials in which tagged smolts (totalling 283 347 fish; 1996–2008) were released as paired control and parasiticide-treated groups into 10 areas of Ireland and Norway. All experimental fish were infection-free when released into freshwater, and a proportion of each group was recovered as adult recruits returning to coastal waters 1 or more years later. Treatment had a significant positive effect on survival to recruitment, with an overall effect size (odds ratio) of 1.29 that corresponds to an estimated loss of 39 per cent (95% CI: 18–55%) of adult salmon recruitment. The parasitic crustaceans were probably acquired during early marine migration in areas that host large aquaculture populations of domesticated salmon, which elevate local abundances of ectoparasitic copepods—particularly Lepeophtheirus salmonis. These results provide experimental evidence from a large marine ecosystem that parasites can have large impacts on fish recruitment, fisheries and conservation. PMID:23135680

Transmission dynamics of parasitic sea lice from farm to wild salmon

PubMed Central

Krkošek, Martin; Lewis, Mark A; Volpe, John P

2005-01-01

Marine salmon farming has been correlated with parasitic sea lice infestations and concurrent declines of wild salmonids. Here, we report a quantitative analysis of how a single salmon farm altered the natural transmission dynamics of sea lice to juvenile Pacific salmon. We studied infections of sea lice (Lepeophtheirus salmonis and Caligus clemensi ) on juvenile pink salmon (Oncorhynchus gorbuscha) and chum salmon (Oncorhynchus keta) as they passed an isolated salmon farm during their seaward migration down two long and narrow corridors. Our calculations suggest the infection pressure imposed by the farm was four orders of magnitude greater than ambient levels, resulting in a maximum infection pressure near the farm that was 73 times greater than ambient levels and exceeded ambient levels for 30 km along the two wild salmon migration corridors. The farm-produced cohort of lice parasitizing the wild juvenile hosts reached reproductive maturity and produced a second generation of lice that re-infected the juvenile salmon. This raises the infection pressure from the farm by an additional order of magnitude, with a composite infection pressure that exceeds ambient levels for 75 km of the two migration routes. Amplified sea lice infestations due to salmon farms are a potential limiting factor to wild salmonid conservation. PMID:15870031

Two novel male-associated peroxinectin genes are downregulated by exposure to delousing drugs in Caligus rogercresseyi.

PubMed

Núñez-Acuña, Gustavo; Gallardo-Escárate, Cristian

2015-02-15

Peroxinectin (PX) is a protein involved in cell adhesion, peroxidase activities, and the encapsulation of invaders in diverse species, including parasitic copepods. Recently, a transcript denoted peroxinectin-like was identified in the salmon louse Lepeophtheirus salmonis, and this was significantly correlated with the immune response of host fish. Thus, the PX gene is a potential candidate to evaluate host-parasite interactions, as well as to analyze responses to delousing drugs used in the salmon aquaculture industry worldwide. The objective of this study was to identify Peroxinectin transcripts in the Chilean salmon louse Caligus rogercresseyi, and to determine expression levels after exposition to the antiparasitics deltamethrin and azamethiphos. Two novel transcript homologs to peroxinectins were identified from a transcriptomic library of C. rogercresseyi. Moreover, in silico gene transcription levels were evaluated through RNA-seq analyses based on unique gene read levels in transcriptomic libraries that were constructed from sea lice exposed to delousing drugs. The identified transcripts were named Peroxinectin-Cr1 and Peroxinectin-Cr2, which, respectively, had lengths of 2543 and 2555 base pairs. Both PX transcripts were highly associated with male adults, and transcription levels were significantly reduced by deltamethrin and azamethiphos. This result suggests a modulation of peroxinectin in response to delousing drugs. Copyright © 2014 Elsevier B.V. All rights reserved.

The Luna stain, an improved selective stain for detection of microsporidian spores in histologic sections

PubMed Central

Peterson, Tracy S.; Spitsbergen, Jan M.; Feist, Stephen W.; Kent, Michael L.

2014-01-01

Microsporidia in histologic sections are most often diagnosed by observing spores in host tissues. Spores are easy to identify if they occur in large aggregates or xenomas when sections are stained with hematoxylin and eosin (H&E). However, individual spores are not frequently detected in host tissues with conventional H&E staining, particularly if spores are scattered within the tissues, areas of inflammation or small spores in nuclei (i.e., Nucleospora salmonis). Hence, a variety of selective stains that enhance visualization of spores are recommended. We discovered that the Luna stain, used to highlight eosinophils, red blood cells and chitin in arthropods and other invertebrates, also stains spores of Pseudoloma neurophilia. We compared this stain to the Gram, Fite’s acid fast, Giemsa, and H&E stains on eight aquatic microsporidian organisms that were readily available in our two laboratories: Loma salmonae, Glugea anomala, Pseudoloma neurophilia, Pleistophora hyphessobryconis, Pleistophora vermiformis, Glugea sp., Steinhausia mytilovum and an unidentified microsporidian from E. sinensis, UK. Based on tinctorial properties and background staining, the Luna stain performed better for detection of 6 of the 8 microsporidia. Gram stain was superior for the two microsporidia from invertebrates, Steinhausia mytilovum and the unidentified microsporidian from E. sinensis. PMID:21848126

Luna stain, an improved selective stain for detection of microsporidian spores in histologic sections.

PubMed

Peterson, Tracy S; Spitsbergen, Jan M; Feist, Stephen W; Kent, Michael L

2011-06-16

Microsporidia in histologic sections are most often diagnosed by observing spores in host tissues. Spores are easy to identify if they occur in large aggregates or xenomas when sections are stained with hematoxylin and eosin (H&E). However, individual spores are not frequently detected in host tissues with conventional H&E staining, particularly if spores are scattered within the tissues, areas of inflammation, or small spores in nuclei (i.e. Nucleospora salmonis). Hence, a variety of selective stains that enhance visualization of spores is recommended. We discovered that the Luna stain, used to highlight eosinophils, red blood cells, and chitin in arthropods and other invertebrates, also stains spores of Pseudoloma neurophilia. We compared this stain to the Gram, Fite's acid fast, Giemsa, and H&E stains on 8 aquatic microsporidian organisms that were readily available in our 2 laboratories: Loma salmonae, Glugea anomala, Pseudoloma neurophilia, Pleistophora hyphessobryconis, Pleistophora vermiformis, Glugea sp., Steinhausia mytilovum, and an unidentified microsporidian from UK mitten crabs Eriocheir sinensis. Based on tinctorial properties and background staining, the Luna stain performed better for detection of 6 of the 8 microsporidia. Gram stain was superior for the 2 microsporidia from invertebrates: S. mytilovum and the unidentified microsporidian from E. sinensis.

Investigations into the temporal development of epitheliocystis infections in brown trout: a histological study.

PubMed

Guevara Soto, M; Vidondo, B; Vaughan, L; Rubin, J-F; Segner, H; Samartin, S; Schmidt-Posthaus, H

2017-06-01

Epitheliocystis in Swiss brown trout (Salmo trutta) is a chlamydial infection, mainly caused by Candidatus Piscichlamydia salmonis and Candidatus Clavichlamydia salmonicola. To gain a better understanding of the temporal development of infections in wild brown trout, we investigated epitheliocystis infections during the course of the summer and autumn months of a single year (2015), and compared this to sampling points over the span of the years 2012-2014. The survey focused on tributaries (Venoge and Boiron) of the Rhone flowing in to Lake Geneva. When evaluated histologically, epitheliocystis infections were found throughout the period of investigation with the exception of the month of June. Fifty to 86 animals per sampling were investigated. Highest prevalence and infection intensities were seen in September. A correlation between epitheliocystis infection and water temperatures was not evident. Interyear comparison revealed consistent levels of prevalence and infection intensities in late summer. The absence of infections in June, combined with the consistent interyear results, indicates seasonal fluctuation of epitheliocystis infections in brown trout with a reservoir persisting during winter months from which infections can re-initiate each year. This could either be at levels below detection limits within the brown trout population itself or in an alternative host. © 2016 John Wiley & Sons Ltd.

Parasites of Bloater Coregonus hoyi (Salmonidae) from Lake Michigan, U.S.A

USGS Publications Warehouse

Madenjian, Charles P.; Muzzall, Patrick M.

2013-01-01

In total, 158 bloaters Coregonus hoyi collected in September and October 2011 from 4 Lake Michigan, U.S.A., ports were examined for parasites. The ports included Waukegan (WK), Illinois; Port Washington (PW) and Sturgeon Bay (SB), Wisconsin; and Saugatuck (SG), Michigan. Parasites found in bloaters by port were cestodes Cyathocephalus truncatus (WK, PW, and SB) and Eubothrium salvelini (WK, PW, SB, and SG); the nematode Cystidicola farionis (WK, PW, SB, and SG); acanthocephalans Acanthocephalus dirus (WK and PW), Echinorhynchus salmonis (WK, PW, and SB), and Neoechinorhynchus tumidus (SB); and the copepod Salmincola corpulentus (WK and PW). Gravid individuals of all parasite species were found except for E. salvelini and A. dirus. Cystidicola farionis had the highest prevalence at each port, and the highest mean intensity and mean abundance at PW. The numbers of C. farionis at PW were significantly higher than those at WK and SB. Echinorhynchus salvelini had the highest mean intensities and mean abundances at WK, SB, and SG. The values for parasite species richness in bloaters were similar among ports. The total numbers of parasites were similar between WK and PW, but they were higher at these ports than at SB. The parasite faunas of bloaters were characterized by autogenic helminth species.

Using Agent-Based Modelling to Predict the Role of Wild Refugia in the Evolution of Resistance of Sea Lice to Chemotherapeutants

PubMed Central

McEwan, Gregor F.; Groner, Maya L.; Fast, Mark D.; Revie, Crawford W.

2015-01-01

A major challenge for Atlantic salmon farming in the northern hemisphere is infestation by the sea louse parasite Lepeophtheirus salmonis. The most frequent method of controlling these sea louse infestations is through the use of chemical treatments. However, most major salmon farming areas have observed resistance to common chemotherapeutants. In terrestrial environments, many strategies employed to manage the evolution of resistance involve the use of refugia, where a portion of the population is left untreated to maintain susceptibility. While refugia have not been deliberately used in Atlantic salmon farming, wild salmon populations that migrate close to salmon farms may act as natural refugia. In this paper we describe an agent-based model that explores the influence of different sizes of wild salmon populations on resistance evolution in sea lice on a salmon farm. Using the model, we demonstrate that wild salmon populations can act as refugia that limit the evolution of resistance in the sea louse populations. Additionally, we demonstrate that an increase in the size of the population of wild salmon results in an increased effect in slowing the evolution of resistance. We explore the effect of a population fitness cost associated with resistance, finding that in some cases it substantially reduces the speed of evolution to chemical treatments. PMID:26485023

Ecology of an estuarine mysid shrimp in the Columbia River (USA)

USGS Publications Warehouse

Haskell, C.A.; Stanford, J.A.

2006-01-01

The estuarine mysid, Neomysis mercedis, has colonized John Day and other run-of-the-river Reservoirs of the Columbia River, over 400 km from the estuary. In John Day Reservoir N. mercedis numbers peaked (2 m-3) in August in areas near the dam in association with lower water velocity and softer bottom than at the upstream sampling sites. Neomysis broods were primarily released in late spring and early fall. Gut content analysis showed that Neomysis feeds mostly on cladoceran zooplankton and rotifers in John Day Reservoir. Diel vertical migration was documented, with daytime distribution restricted to the bottom and preferentially to the soft-textured sediments in the deepest areas. Common pelagic fishes in the reservoir, especially juvenile American shad (Alosa sapidissima) and chinook salmon (Oncorhynchus tshawytscha), are daytime zooplankton feeders that cannot prey on Neomysis owing to mysid diel vertical migration. Thus, Neomysis has become an important food web component in John Day Reservoir. We also collected N. mercedis further upstream in Lower Granite Reservoir, where another estuarine crustacean, Corophium salmonis, also is reported, underscoring the need to better understand the role of these estuarine invertebrates in the trophic ecology of the Columbia River. Copyright ?? 2006 John Wiley & Sons, Ltd.

The identification of plankton tropical status in the Wonokromo, Dadapan and Juanda extreme water estuary

NASA Astrophysics Data System (ADS)

Sari, L. A.; Satyantini, W. H.; Manan, A.; Pursetyo, K. T.; Dewi, N. N.

2018-04-01

Wonokromo, Dadapan and Juanda estuaries are extreme waters located around Surabaya environment. This is because of a lot of organic material intake, which provided nutrients for plankton growth. In addition, the waters is also dynamic in reason of physico-chemical, geological and biological processes controlled by the tides and freshwater run-off from the river that empties into it. The objective of this study was to identify the presentation of plankton in extreme waters based on brightness and ammonia level. The study was conducted in January 2017. Three sampling locations were Wonokromo, Dadapan and Juanda estuaries. Each station consists of three points based on distances, which were 400, 700, and 1000 meters from the coastline. The brightness in Wonokromo, Dadapan, and Juanda environment was 60, 40, and 100 cm, respectively. The result of ammonia in Wonokromo, Dadapan, and Juanda estuary was 0.837, 0.626, and 0.396 mg/L, correspondingly. Nine classes of phytoplankton’s were found in three locations (bacillariophyceae, dynophyceae, chlorophyceae, cyanophyceae, crysophyceae, euglenoidea, trebouxlophyceae, mediophyceae, and nitachiaceae) and five classes of zooplanktons (maxillopoda, hexanuplia, copepoda, malacostraca, and oligotrichea). The density of plankton in Wonokromo, Dadapan and Juanda environments, was 37.64, 63.80, and 352.85 cells/L, respectively.

Food of young-of-the-year lake trout (Salvelinus namaycush) in Presque Isle Harbor, Lake Superior

USGS Publications Warehouse

Swedberg, Donald V.; Peck, James W.

1984-01-01

The food habits of young lake trout (Salvelinus namaycush) were studied by examining the digestive tracts of 293 young-of-the-year collected in Presque Isle Harbor, Lake Superior. Lake trout in the 25 to 27-mm length range started to eat food organisms before all of their yolk material was absorbed. Organisms consumed by the 25 to 27-mm young-of-the-year included Chironomidae, Copepoda (Harpacticoida, Calanoida, Cyclopoida), and Cladocerea (Daphnia spp., Bosmina sp., Chydorus sp.). Chironomid pupae and chironomid larvae accounted for 74% and 5%, respectively, of the total volume of food eaten by the young lake trout in Presque Isle Harbor. Although copepods, cladocerans, and mysids were present in many stomachs, their contribution to the total volume of food was only 15%. Some lake trout in the 32 to 54-mm length range had consumed fry of sculpin (Cottus spp.) or rainbow smelt (Osmerus mordax), but the overall contribution of fish fry to the total volume of food was only 4% (frequency of occurrence, 10%). The lake trout in Presque Isle Harbor fed heavily on planktonic organisms, sparingly on benthic organisms, and were opportunistic feeders that appeared to prey on whatever forage organisms were available in the shallow nearshore waters.

Plankton community and the relationship with the environment in saline lakes of Onon-Torey plain, Northeastern Mongolia.

PubMed

Afonina, Ekaterina Yu; Tashlykova, Natalya A

2018-02-01

The plankton community of sixteen saline lakes located on Onon-Torey plain (Northeastern Mongolia) during the filling phase and the raising of the water level was investigated in July 2011. Thirty-five taxa of phytoplankton and thirty-one species of zooplankton were found. For phytoplankton, blue-green algae ( Merismopedia elegans , Anabaenopsis elenkinii , Arthrospora fusiformis , Spirulina major , Lyngbya sp., Oscillatoria sp.) and green algae ( Monoraphidium minutum , Tetrastrum komarekii , Ankyra ocellata , Oocystis sp.) were dominant. For zooplankton, Filinia longiseta, Brachionus plicatilis , B. variabilis , Hexarthra mira (Rotifera), Daphnia magna , Moina brachiata , M. mongolica (Cladocera), Arctodiaptomus bacillifer , Mixodiaptomus incrassatus , Metadiaptomus asiaticus (Copepoda) dominated. Mineralization, active hydrogen ratio, dissolved oxygen and water temperature were the main factors influencing the diversity, structure and distribution of plankton organisms in the steppe lakes during low water level. The RDA analysis for phytoplankton and zooplankton from different lakes was carried out for selected two groups which included lakes and a subset related species. The first group is of oligohaline and mesohaline lakes in which mostly green algae, rotifers and copepods inhabit. The second group is of mesohaline and polyhaline lakes with mainly blue-green algae , some crustaceans and rotifers inhabiting. High abundance and biomass of Spirulina major , Oscillatoria sp. and Brachionus variabilis were observed in lakes with high mineralization, pH and temperature.

Metazoan ectoparasites of Atlantic mackerel, Scomber scombrus (Teleostei: Scombridae): macro- and microhabitat distribution.

PubMed

Castro, Ricardo; Santos, Maria João

2013-10-01

Parasites are affected by the environment where their hosts live, having a specific distribution among their hosts and occupying a well-defined microhabitat. The present work aims to describe the metazoan ectoparasite fauna of Scomber scombrus, namely its distribution at the macro- and microhabitat levels. For that, fish from two different Portuguese regions, Matosinhos (n = 40) and Figueira da Foz (n = 39), were examined for macroectoparasites. S. scombrus of Matosinhos presented four different parasite species, whilst fish from Figueira da Foz presented five species. All parasites belonged to Monogenea, Copepoda, or Isopoda. The main differences between infection levels of fish from the two localities were found in Grubea cochlear (higher infection levels in Matosinhos) and Caligus pelamydis (where the highest values were found in Figueira da Foz). Regarding the microhabitat of the reported ectoparasites, it could be seen that every species has a very specific distribution within the host: G. cochlear and Kuhnia scombri have a preference for the inner medial areas of gills, Kuhnia sprostonae for the pseudobranchs, and C. pelamydis for the internal wall of opercula. The numerical and functional responses to interspecific competition were absent. These results support the idea that the parasite driving forces of community structure are the reinforcement of reproductive barriers and the enhancement of chances to mate.

[Limnetic zooplankton run-off a high-head dam and their fate in a river with high current velocity (case of the Krasnoiarsk hydroelectric power station on the Yenisei river].

PubMed

Dubovskaia, O P; Gladyshev, M I; Makhutova, O N

2004-01-01

The vertical distribution of net zooplankton in head-water of Krasnoyarsk hydroelectric power station and its horizontal distribution in the tail-water were studied during two years in winter and summer seasons. In order to distinguish living and dead individuals the special staining was used. It was revealed that on average 77% of living plankton pass through high-head dam with deep water scoop to the tailwater. While passing through dam aggregates some individuals of the reservoir plankton are traumatized and die, that results in some increase of portion of dead individuals in the tail water near dam (from 3 to 6%). Alive zooplankton passed through the dam aggregates is eliminated under the Upper Yenisei highly turbulent conditions. There is approximately 10% of it in 32 km from the dam if compare with biomass in 20-40 m layer of reservoir, the portion of dead increases to 11%. The biomass of zooplankton suspended in the water column of the tail-water sometimes increases (till > 1 g/m3) due to large Copepoda Heteroscope borealis, which inhabits near-bottom and near-shore river zones and can be found in the central part of the river during reproductive period. Limnetic zooplankton from the reservoir cannot be considered as important food for planktivores in the tail-water.

Response of Aquatic Invertebrates to Ecological Rehabilitation of Southeastern USA Depressional Wetlands

DOE Office of Scientific and Technical Information (OSTI.GOV)

Batzer, Darold P.; Taylor, Barbara E.; DeBiase, Adrienne E.

We assessed aquatic invertebrate response to ecological rehabilitation treatment in 20 depression wetlands on the Savannah River Site, South Carolina, USA. All wetlands had been ditched for 50+ years. Sixteen of the 20 wetlands received rehabilitation treatment, and four wetlands remained untreated as a control group. Treatment included logging of all trees, plugging drainage ditches, and planting wetland trees and grasses. Hydroperiods were consequently extended in most of the treatment wetlands. As part a larger study, we sampled macroinvertebrates and microcrustaceans during the pre-habilitation (1998–2000) and rehabilitation (2001–2003) phases. Our study spanned 2 years of high rainfall (1998 and 2003)more » and 4 years of low rainfall (1999–2002). Samples were collected bimonthly from any wetlands holding water. Macroinvertebrate assemblages in treatment wetlands in 2003 had changed from previous years (1998–2002) and compared to control wetlands (1998–2003), with abundances of Baetidae, Coenagrionidae, Dytiscidae, Chironomidae, and Chaoboridae driving variation. For microcrustaceans (Copepoda and Branchiopoda, including Cladocera, Anostraca and Laevicaudata), assemblage composition and species richness responded mainly to hydrologic conditions. Rehabilitation efforts in these wetlands induced diverse and abundant invertebrate communities to develop, but some responses appeared opportunistic; several taxa that benefitted were not typical residents of depressional wetlands in the region.« less

Comprehensive Transcriptome Study to Develop Molecular Resources of the Copepod Calanus sinicus for Their Potential Ecological Applications

PubMed Central

Yang, Qing; Sun, Fanyue; Yang, Zhi; Li, Hongjun

2014-01-01

Calanus sinicus Brodsky (Copepoda, Crustacea) is a dominant zooplanktonic species widely distributed in the margin seas of the Northwest Pacific Ocean. In this study, we utilized an RNA-Seq-based approach to develop molecular resources for C. sinicus. Adult samples were sequenced using the Illumina HiSeq 2000 platform. The sequencing data generated 69,751 contigs from 58.9 million filtered reads. The assembled contigs had an average length of 928.8 bp. Gene annotation allowed the identification of 43,417 unigene hits against the NCBI database. Gene ontology (GO) and KEGG pathway mapping analysis revealed various functional genes related to diverse biological functions and processes. Transcripts potentially involved in stress response and lipid metabolism were identified among these genes. Furthermore, 4,871 microsatellites and 110,137 single nucleotide polymorphisms (SNPs) were identified in the C. sinicus transcriptome sequences. SNP validation by the melting temperature (T m)-shift method suggested that 16 primer pairs amplified target products and showed biallelic polymorphism among 30 individuals. The present work demonstrates the power of Illumina-based RNA-Seq for the rapid development of molecular resources in nonmodel species. The validated SNP set from our study is currently being utilized in an ongoing ecological analysis to support a future study of C. sinicus population genetics. PMID:24982883

Lighten up the dark: metazoan parasites as indicators for the ecology of Antarctic crocodile icefish (Channichthyidae) from the north-west Antarctic Peninsula.

PubMed

Kuhn, Thomas; Zizka, Vera M A; Münster, Julian; Klapper, Regina; Mattiucci, Simonetta; Kochmann, Judith; Klimpel, Sven

2018-01-01

Due to its remote and isolated location, Antarctica is home to a unique diversity of species. The harsh conditions have shaped a primarily highly adapted endemic fauna. This includes the notothenioid family Channichthyidae. Their exceptional physiological adaptations have made this family of icefish the focus of many studies. However, studies on their ecology, especially on their parasite fauna, are comparatively rare. Parasites, directly linked to the food chain, can function as biological indicators and provide valuable information on host ecology (e.g., trophic interactions) even in remote habitats with limited accessibility, such as the Southern Ocean. In the present study, channichthyid fish ( Champsocephalus gunnari : n = 25, Chaenodraco wilsoni : n = 33, Neopagetopsis ionah : n = 3, Pagetopsis macropterus : n = 4, Pseudochaenichthys georgianus : n = 15) were collected off South Shetland Island, Elephant Island, and the tip of the Antarctic Peninsula (CCAML statistical subarea 48.1). The parasite fauna consisted of 14 genera and 15 species, belonging to the six taxonomic groups including Digenea (four species), Nematoda (four), Cestoda (two), Acanthocephala (one), Hirudinea (three), and Copepoda (one). The stomach contents were less diverse with only Crustacea (Euphausiacea, Amphipoda) recovered from all examined fishes. Overall, 15 new parasite-host records could be established, and possibly a undescribed genotype or even species might exist among the nematodes.

Gill parasites of fish from two estuaries in northeastern Brazil: new hosts and geographical records.

PubMed

Golzio, Jéssica E S A; Falkenberg, Júlia M; Praxedes, Rayssa C G; Coutinho, Anderson S; Laurindo, Mylena K; Pessanha, André; Madi, Rubens R; Patrício, Joana; Vendel, Ana L; Souza, Geza T R; Melo, Cláudia M; Lacerda, Ana Carolina F

2017-01-01

Parasites are important components of communities and constitute great part of the biological diversity found in ecosystems, providing valuable information about their hosts and the environment in which they live. However, despite its importance, parasitic diversity is still not well known in some regions of Brazil, especially with respect to fish parasites in the Northeast Region. The present study aims to perform the survey of gill parasites of fish from two tropical estuaries located in northeastern Brazil: Paraíba and Mamanguape rivers. Two collections were made in each estuary, one during the dry period (November / 2013) and the other during the rainy season (July / 2014). The fish were caught using a beach seine net, dragged along the main channel margin. After the identification, biometry and necropsy of the fish, their parasites were collected, stored and identified. For each species of parasite, the values ​​of prevalence, mean intensity and mean abundance were calculated. Of the 882 examined fish, belonging to four species, 145 were parasitized by at least one species of parasite. In total, 18 taxa of parasites of the groups Monogenea, Digenea, Nematoda, Copepoda and Isopoda were recorded, being the copepod Acusicola brasiliensis the most abundant species of parasite.

Response of Aquatic Invertebrates to Ecological Rehabilitation of Southeastern USA Depressional Wetlands

DOE PAGES

Batzer, Darold P.; Taylor, Barbara E.; DeBiase, Adrienne E.; ...

2015-07-02

We assessed aquatic invertebrate response to ecological rehabilitation treatment in 20 depression wetlands on the Savannah River Site, South Carolina, USA. All wetlands had been ditched for 50+ years. Sixteen of the 20 wetlands received rehabilitation treatment, and four wetlands remained untreated as a control group. Treatment included logging of all trees, plugging drainage ditches, and planting wetland trees and grasses. Hydroperiods were consequently extended in most of the treatment wetlands. As part a larger study, we sampled macroinvertebrates and microcrustaceans during the pre-habilitation (1998–2000) and rehabilitation (2001–2003) phases. Our study spanned 2 years of high rainfall (1998 and 2003)more » and 4 years of low rainfall (1999–2002). Samples were collected bimonthly from any wetlands holding water. Macroinvertebrate assemblages in treatment wetlands in 2003 had changed from previous years (1998–2002) and compared to control wetlands (1998–2003), with abundances of Baetidae, Coenagrionidae, Dytiscidae, Chironomidae, and Chaoboridae driving variation. For microcrustaceans (Copepoda and Branchiopoda, including Cladocera, Anostraca and Laevicaudata), assemblage composition and species richness responded mainly to hydrologic conditions. Rehabilitation efforts in these wetlands induced diverse and abundant invertebrate communities to develop, but some responses appeared opportunistic; several taxa that benefitted were not typical residents of depressional wetlands in the region.« less

Structure of Mesozooplankton Communities in the Coastal Waters of Morocco

NASA Astrophysics Data System (ADS)

Lidvanov, V. V.; Grabko, O. G.; Kukuev, E. I.; Korolkova, T. G.

2018-03-01

Mero- and holoplanktonic organisms from 23 large taxa have been detected in the coastal waters of Morocco. Seven Cladocera species and 164 Copepoda species were identified. Copepod fauna mostly consisted of oceanic epipelagic widely tropical species, but the constant species group (frequency of occurrence over 50%) included neritic and neritic-oceanic widely tropical species. The neritic community that formed a biotopic association with coastal upwelling waters and the distant-neritic community associated with Canary Current waters were the two major communities detected. The former community was characterized by a high abundance and biomass (5700 ind./m3 and 260 mg/m3) and predominance of neritic species. The trophic structure was dominated by thin filter feeders, mixed-food consumers, and small grabbers; the species structure was dominated by Paracalanus indicus, Acartia clausi, and Oncaea curta; the indices of species diversity (3.07 bit/ind.) and evenness (0.63) were relatively low. The latter community was characterized by low abundance and biomass (1150 ind./m3 and 90 mg/m3); variable biotopic, trophic, and species structure; and higher Shannon indices (3.99 bit/ind.) and Pielou (0.75). Seasonal variation of the abundance of organisms was not detected in the communities. Anomalous mesozooplankton states were observed in summer 1998 and winter 1998-1999.

Effects of seven diets on the population dynamics of laboratory cultured Tisbe holothuriae Humes (Copepoda, Harpacticoida)

NASA Astrophysics Data System (ADS)

Miliou, H.; Moraïtou-Apostolopoulou, M.

1991-09-01

The harpacticoid copepod Tisbe holothuriae was collected from Saronicos Gulf (Greece) and reared under constant laboratory conditions. In order to study the effects of food on the population dynamics, seven diets were tested: the seaweed Ulva; five artificial compound feeds: the liquid Fryfood® (Waterlife), a powder of Mytilus, yeast, soya and Spirulina, respectively; and a mixed diet consisting of Ulva and Fryfood. The life cycle parameters (mortality, sex ratio, generation time, offspring production) were measured, and the demographic variables [mean generation time (T), net reproductive rate (Ro), and intrinsic rate of natural increase (rm)] were determined. As to their efficiency regarding population dynamics, the diets ranked as follows: (1) Ulva+Fryfood, (2), Ulva, (3) Fryfood, (4) Mytilus, (5) soya, (6) yeast, and (7) Spirulina. In this order they cause a progressive increase of both larval mortality and generation time, a progressive decrease of sex ratio, number of offspring per egg sac, number of egg sacs per female and, consequently, of Ro and rm. The observed differences between diets were most pronounced with respect to offspring production. Of the compound diets, those containing animal extracts were more efficient than those containing vegetable materials. Ulva plays an important role in the nutrition of T. holothuriae, favouring offspring production as well as larval survival, development and pigmentation. Ulva in combination with Fryfood led to a greater copepodid survival and offspring production. This mixed diet proved to be the most favourable for rearing the Greek population of t. holothuriae, resulting in an efficient intrinsic rate of natural increase (rm=0.304) of the population.

Temporal fluctuation and reproduction of Thermocyclops decipiens (Copepoda, Cyclopoida) in an eutrophic lake of central Brazil.

PubMed

Padovesi-Fonseca, Claudia; de Mendonça-Galvão, Luciana; Rocha, Diogo Libânio Pereira

2002-03-01

Lake Paranoá is an eutrophic reservoir situated in the urban region of Brasília. This study was carried out in a fixed collection station located in the Riacho Fundo branch of the reservoir. Zooplankton samples were collected at intervals of 3-5 d at 9:00 a.m. during two months in the dry and rainy seasons for two years (dry-1996, rainy-1997, dry-1997 and rainy-1998), using a 64 microns-mesh plankton net. The most predominant species was Thermocyclops decipiens (about 50% of the total zooplankton community), which during the whole period had a high reproductive rate. The highest densities were found in the dry-1996 season (1700 ind/l for nauplii), and also fluctuated widely overtime. Nauplii stages dominated during the four periods, comprising 50-75% of the total population density. Ovigerous females peaked in the dry-1996 and rainy-1997 seasons, with 20-30% of the total females. The largest peak in egg production occurred during the dry-1996 season, and the total egg production was 2.0 x 10(3) eggs/l. Mesocyclops longisetus is a first record for Lake Paranoá. The ecological factors that determine the success of T. decipiens in eutrophic systems are related to omnivorous feeding habits and prey-predator interactions.

A new subspecies of Nitokra affinis Gurney, 1927 (Copepoda, Harpacticoida) from the Caribbean coast of Colombia

PubMed Central

Fuentes-Reinés, Juan M.; Suárez-Morales, Eduardo

2014-01-01

Abstract Plankton samples from Laguna Navio Quebrado, La Guajira, northern Colombia, yielded male and female specimens of an harpacticoid copepod that was first identified as the widely distributed species Nitokra affinis Gurney, 1927 for which at least four subspecies have been described from different geographic areas. A more detailed examination of the Colombian specimens revealed that it differs from the other morphs so far considered as subspecies. The Colombian specimens differ from the other four known subspecies in the following aspects: (1) rostrum with long projection, (2) relatively long exopod of P1, almost as long as first endopodal segment, (3) endopodal and exopodal rami of P2 equally long, (4) a reduced number of endopodal setal elements of the male P5. It also differs from N. a. californica Lang in details of the ornamentation of the urosomites. Descriptions and illustrations of this new subspecies, the first one described from the Neotropical region, are presented together with a key to the five known subspecies of Nitokra affinis. As in many other cases of presumedly widespread species of harpacticoids, it is possible that N. affinis represents a species complex with more restricted distributional patterns, a notion that certainly deserves further study. PMID:24574850

A new species of Peltidium Philippi, 1839 (Crustacea, Copepoda, Harpacticoida) from the Pacific coast of Mexico

PubMed Central

Suárez-Morales, Eduardo; Jarquín-González, Jani

2013-01-01

Abstract During the analysis of phytal meiobenthic samples collected from a rocky-sandy beach in the state of Nayarit, in the Mexican Pacific, several specimens of harpacticoid copepods were obtained and taxonomically examined. These specimens were found to represent an undescribed species of the peltidiid genus Peltidium Philippi, 1839. The new species, Peltidium nayarit sp. n. is described herein. It resembles Peltidium nichollsi Geddes and Peltidium lerneri Geddes from Bahamas but also the widespread Peltidium speciosum Thompson & Scott and Peltidium purpureum Philippi. The new species from the Mexican Pacific differs from its known congeners by its possession of a unique combination of characters, including a modified pectinate seta on the antennary exopod, three terminal setae on the second endopodal segment of leg 1, third exopodal segment of leg 1 with three elements, inner terminal claw twice as long as outer claw, female fifth leg with 5 exopodal setae, exopodal setae I-III stout, spinulose and seta IV being as long as seta V. This is the second species of the family known to be distributed in the Eastern Tropical Pacific and in Mexico. Pending additional data, the distribution of this species appears to be restricted to this area of the Mexican Pacific. PMID:24003319

A new species of Metacyclops Kiefer, 1927 (Copepoda, Cyclopidae, Cyclopinae) from the Chihuahuan desert, northern Mexico

PubMed Central

Mercado-Salas, Nancy F.; Suárez-Morales, Eduardo; Maeda-Martínez, Alejandro M.; Silva-Briano, Marcelo

2013-01-01

Abstract A new species of the freshwater cyclopoid copepod genus Metacyclops Kiefer, 1927 is described from a single pond in northern Mexico, within the binational area known as the Chihuahuan Desert. This species belongs to a group of Metacyclops species with a 3443 spine formula of swimming legs. It is morphologically similar to Metacyclops lusitanus Lindberg, 1961 but differs from this and other congeners by having a unique combination of characters, including a caudal rami length/width proportion of 3.5–3.8, a innermost terminal seta slightly longer than the outermost terminal seta, intercoxal sclerites of legs 1-4 naked, a strong apical spine of the second endopodal segment of leg 1 and one row of 6-8 small spinules at the insertion of this spine. The finding of this species represents also the first record of the genus in Mexico and the third in North America, where only two other species, Metacyclops gracilis (Lilljeborg, 1853)and Metacyclops cushae Reid, 1991 have been hitherto reported. This is also the first continental record of a species of Metacyclops from an arid environment in the Americas. This species appears to be endemic to the Chihuahuan Desert, thus emphasizing the high endemicity of this area. PMID:23794845

New species of the genus Mesocletodes Sars, 1909 from the deep Gulf of California (Copepoda, Harpacticoida).

PubMed

Gómez, Samuel

2018-01-01

Investigations on the effects of the oxygen minimum zone on the distribution, abundance, and diversity of deep-sea benthic and pelagic fauna of the Gulf of California and Eastern Tropical Pacific has received attention recently. However, very little is known about the diversity of deep-sea benthic harpacticoids from this region, and only three species, Ancorabolus hendrickxi Gómez & Conroy-Dalton, 2002, Ceratonotus elongatus Gómez & Díaz, 2017 and Dendropsyllus californiensis Gómez & Díaz, 2017, have been described so far. The genus Mesocletodes Sars, 1909 is one of the most common and abundant genera of deep-sea harpacticoids. This genus has been traditionally subdivided into two species groups, the abyssicola and the inermis groups, based on the presence/absence of a dorsal cuticular process on the cephalothorax and anal somite, but some species have been reported to deviate from this scheme. As a result of their investigations, other researchers proposed the monophyly of the abyssicola group, and suggested the probable monophyly of two other species-groups. In this paper, the descriptions of three new species of the genus Mesocletodes from the deep sea of the Gulf of California are presented with some notes on their relationships with other species. Some comments on the monophyly of the genus are given.

New species of the genus Mesocletodes Sars, 1909 from the deep Gulf of California (Copepoda, Harpacticoida)

PubMed Central

Gómez, Samuel

2018-01-01

Abstract Investigations on the effects of the oxygen minimum zone on the distribution, abundance, and diversity of deep-sea benthic and pelagic fauna of the Gulf of California and Eastern Tropical Pacific has received attention recently. However, very little is known about the diversity of deep-sea benthic harpacticoids from this region, and only three species, Ancorabolus hendrickxi Gómez & Conroy-Dalton, 2002, Ceratonotus elongatus Gómez & Díaz, 2017 and Dendropsyllus californiensis Gómez & Díaz, 2017, have been described so far. The genus Mesocletodes Sars, 1909 is one of the most common and abundant genera of deep-sea harpacticoids. This genus has been traditionally subdivided into two species groups, the abyssicola and the inermis groups, based on the presence/absence of a dorsal cuticular process on the cephalothorax and anal somite, but some species have been reported to deviate from this scheme. As a result of their investigations, other researchers proposed the monophyly of the abyssicola group, and suggested the probable monophyly of two other species-groups. In this paper, the descriptions of three new species of the genus Mesocletodes from the deep sea of the Gulf of California are presented with some notes on their relationships with other species. Some comments on the monophyly of the genus are given. PMID:29706785

To Swim or Not to Swim: Potential Transmission of Balaenophilus manatorum (Copepoda: Harpacticoida) in Marine Turtles.

PubMed

Domènech, Francesc; Tomás, Jesús; Crespo-Picazo, José Luis; García-Párraga, Daniel; Raga, Juan Antonio; Aznar, Francisco Javier

2017-01-01

Species of Balaenophilus are the only harpacticoid copepods that exhibit a widespread, obligate association with vertebrates, i.e., B. unisetus with whales and B. manatorum with marine turtles and manatees. In the western Mediterranean, juveniles of the loggerhead sea turtle, Caretta caretta are the only available hosts for B. manatorum, which has been found occurring at high prevalence (>80%) on them. A key question is how these epibionts are transmitted from host to host. We investigated this issue based on experiments with live specimens of B. manatorum that were cultured with turtle skin. Specimens were obtained from head-started hatchlings of C. caretta from the western Mediterranean. Hatched nauplii crawled only on rough substrates and lacked the ability to swim. Only copepodites IV and V, and adults, were able to perform directional swimming. Legs 2, 3 and 4 played a major role in swimming and were only well-developed in these stages. Nauplii reared in wells with turtle skin readily fed on this item. Late copepodites and adults also fed on turtle skin but did not consume other potential food items such as fish skin, baleen plates or planktonic algae. Evidences suggest that the transmission of B. manatorum should rely on hosts' bodily contacts and/or swimming of late developmental stages between spatially close hosts. The possibility of long-ranged dispersal is unlikely for two reasons. First, all developmental stages seem to depend on turtle skin as a food resource. Second, the average clutch size of ovigerous females was small (< 70 eggs) for free-living phases to successfully contact turtles that occur at very low densities (< 0.6 turtles·km-2) in the western Mediterranean. The high prevalence of B. manatorum in loggerhead turtles in this area raises the question whether these turtles have contacts, or tend to closely aggregate, more than is currently believed.

To Swim or Not to Swim: Potential Transmission of Balaenophilus manatorum (Copepoda: Harpacticoida) in Marine Turtles

PubMed Central

Tomás, Jesús; Crespo-Picazo, José Luis; García-Párraga, Daniel; Raga, Juan Antonio

2017-01-01

Species of Balaenophilus are the only harpacticoid copepods that exhibit a widespread, obligate association with vertebrates, i.e., B. unisetus with whales and B. manatorum with marine turtles and manatees. In the western Mediterranean, juveniles of the loggerhead sea turtle, Caretta caretta are the only available hosts for B. manatorum, which has been found occurring at high prevalence (>80%) on them. A key question is how these epibionts are transmitted from host to host. We investigated this issue based on experiments with live specimens of B. manatorum that were cultured with turtle skin. Specimens were obtained from head-started hatchlings of C. caretta from the western Mediterranean. Hatched nauplii crawled only on rough substrates and lacked the ability to swim. Only copepodites IV and V, and adults, were able to perform directional swimming. Legs 2, 3 and 4 played a major role in swimming and were only well-developed in these stages. Nauplii reared in wells with turtle skin readily fed on this item. Late copepodites and adults also fed on turtle skin but did not consume other potential food items such as fish skin, baleen plates or planktonic algae. Evidences suggest that the transmission of B. manatorum should rely on hosts’ bodily contacts and/or swimming of late developmental stages between spatially close hosts. The possibility of long-ranged dispersal is unlikely for two reasons. First, all developmental stages seem to depend on turtle skin as a food resource. Second, the average clutch size of ovigerous females was small (< 70 eggs) for free-living phases to successfully contact turtles that occur at very low densities (< 0.6 turtles·km−2) in the western Mediterranean. The high prevalence of B. manatorum in loggerhead turtles in this area raises the question whether these turtles have contacts, or tend to closely aggregate, more than is currently believed. PMID:28114412

Evidence for a carrier state of infectious hematopoietic necrosis virus in chinook salmon Oncorhynchus tshawytscha.

PubMed

St Hilaire, S; Ribble, C; Traxler, G; Davies, T; Kent, M L

2001-10-08

In British Columbia, Canada, infectious hematopoietic necrosis virus (IHNV) is prevalent in wild sockeye salmon Oncorhynchus nerka and has caused disease in seawater net-pen reared Atlantic salmon Salmo salar. In this study, chinook salmon Oncorhynchus tshawytscha experimentally exposed to an isolate of IHNV found in British Columbia became carriers of the virus. When Atlantic salmon were cohabited with these virus-exposed chinook salmon, IHNV was isolated from the Atlantic salmon. Identification of chinook salmon populations that have been exposed to IHNV may be difficult, as virus isolation was successful only in fish that were concurrently infected with either Renibacterium salmoninarum or Piscirickettisia salmonis. Also, IHNV-specific antibodies were detected in only 2 of the 70 fish experimentally exposed to the virus. Two samples collected from chinook salmon exposed to IHNV while at a salt water net-pen site had a seroprevalence of 19 and 22%; however, the inconsistencies between our laboratory and field data suggest that further research is required before we can rely on serological analysis for identifying potential carrier populations. Because of the difficulty in determining the exposure status of populations of chinook salmon, especially if there is no concurrent disease, it may be prudent not to cohabit Atlantic salmon with chinook salmon on a farm if there is any possibility that the latter have been exposed to the virus.

Salmon lice – impact on wild salmonids and salmon aquaculture

PubMed Central

Torrissen, O; Jones, S; Asche, F; Guttormsen, A; Skilbrei, O T; Nilsen, F; Horsberg, T E; Jackson, D

2013-01-01

Salmon lice, Lepeophtheirus salmonis, are naturally occurring parasites of salmon in sea water. Intensive salmon farming provides better conditions for parasite growth and transmission compared with natural conditions, creating problems for both the salmon farming industry and, under certain conditions, wild salmonids. Salmon lice originating from farms negatively impact wild stocks of salmonids, although the extent of the impact is a matter of debate. Estimates from Ireland and Norway indicate an odds ratio of 1.1:1-1.2:1 for sea lice treated Atlantic salmon smolt to survive sea migration compared to untreated smolts. This is considered to have a moderate population regulatory effect. The development of resistance against drugs most commonly used to treat salmon lice is a serious concern for both wild and farmed fish. Several large initiatives have been taken to encourage the development of new strategies, such as vaccines and novel drugs, for the treatment or removal of salmon lice from farmed fish. The newly sequenced salmon louse genome will be an important tool in this work. The use of cleaner fish has emerged as a robust method for controlling salmon lice, and aquaculture production of wrasse is important towards this aim. Salmon lice have large economic consequences for the salmon industry, both as direct costs for the prevention and treatment, but also indirectly through negative public opinion. PMID:23311858

Considerations in developing an integrated pest management programme for control of sea lice on farmed salmon in Pacific Canada.

PubMed

Brooks, K M

2009-01-01

In the development of integrated pest management (IPM) plans for the control of sea lice there are some components that are common to many areas. However, effective plans must be tailored to regionally varying environmental and biological factors affecting the severity of sea lice infections. This paper describes factors that would be involved in the development of an IPM plan for sea lice in the Broughton Archipelago, British Columbia. Temperature, salinity and currents affect the production, dispersion and competence of larvae of sea lice, Lepeophtheirus salmonis (Krøyer), as they develop to the infective copepodid stage. This information can be coupled with oceanographic conditions in the Broughton Archipelago and emerging computer models to define zones of infection where infections of new hosts are most likely. Salinity and temperature depend, in part, on river discharge in estuarine systems. River discharge depends on precipitation, snow pack and ambient temperatures, which can be monitored to help forecast the intensity of sea lice infections associated with both farmed and wild hosts. One of the goals of IPM planning is to reduce reliance on pesticides to avoid development of resistance in targeted parasites and to minimize environmental residues. Recommendations for developing an IPM plan specific to the Broughton Archipelago are provided along with a discussion of the additional information needed to refine IPM plans in this and other areas.

Allee effect from parasite spill-back.

PubMed

Krkošek, Martin; Ashander, Jaime; Frazer, L Neil; Lewis, Mark A

2013-11-01

The exchange of native pathogens between wild and domesticated animals can lead to novel disease threats to wildlife. However, the dynamics of wild host-parasite systems exposed to a reservoir of domesticated hosts are not well understood. A simple mathematical model reveals that the spill-back of native parasites from domestic to wild hosts may cause a demographic Allee effect in the wild host population. A second model is tailored to the particulars of pink salmon (Oncorhynchus gorbuscha) and salmon lice (Lepeophtheirus salmonis), for which parasite spill-back is a conservation and fishery concern. In both models, parasite spill-back weakens the coupling of parasite and wild host abundance-particularly at low host abundance-causing parasites per host to increase as a wild host population declines. These findings show that parasites shared across host populations have effects analogous to those of generalist predators and can similarly cause an unstable equilibrium in a focal host population that separates persistence and extirpation. Allee effects in wildlife arising from parasite spill-back are likely to be most pronounced in systems where the magnitude of transmission from domestic to wild host populations is high because of high parasite abundance in domestic hosts, prolonged sympatry of domestic and wild hosts, a high transmission coefficient for parasites, long-lived parasite larvae, and proximity of domesticated populations to wildlife migration corridors.

Genetic ontogeny of pancreatic enzymes in Labrus bergylta larvae and the effect of feed type on enzyme activities and gene expression.

PubMed

Hansen, Truls Wergeland; Folkvord, Arild; Grøtan, Espen; Sæle, Øystein

2013-03-01

A newly cultivated wrasse species, Labrus bergylta, have shown great potential for use in Atlantic salmon (Salmo salar) farms in the battle against sea lice (Lepeoptheirus salmonis) infections. Hatchery reared L. bergylta were studied from 2 to 55 DPH to examine the molecular basis of digestive ontogeny related to the pancreas. An isolated feeding trial was performed on 27-34 DPH larvae to compare the effect of diet on enzyme activity and the possible exogenous contribution by live feed. The following genes coding for key pancreatic enzymes were analyzed by qPCR: trypsin, Cyp7 A1, BAL, sPLA(2) 1B, amylase and pancreatic chitinase. Enzyme activity was measured on trypsin, neutral lipase, sPLA(2), amylase and chitinase in fed and unfed larvae. We did not observe any effects of the formulated diet v.s. rotifers on enzyme activities of neutral lipase, chitinase and sPLA(2). However, a probable feed-dependency was observed at a transcriptional level, where rotifers seem to stimulate upregulation. The regulation of BAL was the only exception, where an upregulation was observed after weaning both in the ontogeny series and the experimental part. Our data on pancreatic chitinase and amylase mRNA levels suggest the importance of carbohydrates in the diet of early larval and juvenile L. bergylta. Copyright © 2012 Elsevier Inc. All rights reserved.

Selective breeding program for sea lice Lepeophtheirus salmonis (Kroyer 1838) at the USDA's National Cold Water Marine Aquaculture Center

USDA-ARS?s Scientific Manuscript database

Sea lice are likely the most economically costly pathogen that has faced the salmon farming industry over the past 40 years. Recent economic estimates put the annual cost of sea lice at $742 million USD in 2012. With the rise of resistance to multiple drugs used to treat sea lice, there has been a s...

Association between sea lice (Lepeophtheirus salmonis) infestation on Atlantic salmon farms and wild Pacific salmon in Muchalat Inlet, Canada.

PubMed

Nekouei, Omid; Vanderstichel, Raphael; Thakur, Krishna; Arriagada, Gabriel; Patanasatienkul, Thitiwan; Whittaker, Patrick; Milligan, Barry; Stewardson, Lance; Revie, Crawford W

2018-03-05

Growth in salmon aquaculture over the past two decades has raised concerns regarding the potential impacts of the industry on neighboring ecosystems and wild fish productivity. Despite limited evidence, sea lice have been identified as a major cause for the decline in some wild Pacific salmon populations on the west coast of Canada. We used sea lice count and management data from farmed and wild salmon, collected over 10 years (2007-2016) in the Muchalat Inlet region of Canada, to evaluate the association between sea lice recorded on salmon farms with the infestation levels on wild out-migrating Chum salmon. Our analyses indicated a significant positive association between the sea lice abundance on farms and the likelihood that wild fish would be infested. However, increased abundance of lice on farms was not significantly associated with the levels of infestation observed on the wild salmon. Our results suggest that Atlantic salmon farms may be an important source for the introduction of sea lice to wild Pacific salmon populations, but that the absence of a dose response relationship indicates that any estimate of farm impact requires more careful evaluation of causal inference than is typically seen in the extant scientific literature.

Impact of anthropogenic activities on water quality and plankton communities in the Day River (Red River Delta, Vietnam).

PubMed

Hoang, Hang Thi Thu; Duong, Thi Thuy; Nguyen, Kien Trung; Le, Quynh Thi Phuong; Luu, Minh Thi Nguyet; Trinh, Duc Anh; Le, Anh Hung; Ho, Cuong Tu; Dang, Kim Dinh; Némery, Julien; Orange, Didier; Klein, Judith

2018-01-08

Planktons are a major component of food web structure in aquatic ecosystems. Their distribution and community structure are driven by the combination and interactions between physical, chemical, and biological factors within the environment. In the present study, water quality and the community structure of phytoplankton and zooplankton were monthly investigated from January to December 2015 at 11 sampling sites along the gradient course of the Day River (Red River Delta, northern Vietnam). The study demonstrated that the Day River was eutrophic with the average values of total phosphorus concentration 0.17 mg/L, total nitrogen concentration 1.98 mg/L, and Chl a 54 μg/L. Microscopic plankton analysis showed that phytoplankton comprised 87 species belonging to seven groups in which Chlorophyceae, Bacillariophyceae, and Cyanobacteria accounted for the most important constituents of the river's phytoplankton assemblage. A total 53 zooplankton species belonging to three main groups including Copepoda, Cladocera, and Rotatoria were identified. Plankton biomass values were greatest in rainy season (3002.10-3 cell/L for phytoplankton and 12.573 individuals/m 3 for zooplankton). Using principal correspondence and Pearson correlation analyses, it was found that the Day River was divided into three main site groups based on water quality and characteristics of plankton community. Temperature and nutrients (total phosphorus and total nitrogen) are key factors regulating plankton abundance and distribution in the Day River.

Effects of habitat structure on the epifaunal community in Mussismilia corals: does coral morphology influence the richness and abundance of associated crustacean fauna?

NASA Astrophysics Data System (ADS)

Nogueira, Marcos M.; Neves, Elizabeth; Johnsson, Rodrigo

2015-06-01

Coral habitat structures increase abundance and richness of organisms by providing niches, easy access to resources and refuge from predators. Corals harbor a great variety of animals; the variation in coral species morphology contributes to the heterogeneity and complexity of habitat types. In this report, we studied the richness and abundance of crustaceans (Decapoda, Copepoda, Peracarida and Ostracoda) associated with three species of Mussismilia exhibiting different growth morphologies, in two different coral reefs of the Bahia state (Caramuanas and Boipeba-Moreré, Brazil). Mussismilia hispida is a massive coral; M. braziliensis also has a massive growth pattern, but forms a crevice in the basal area of the corallum; M. harttii has a meandroid pattern. PERMANOVA analysis suggests significant differences in associated fauna richness among Mussismilia species, with higher values for M. harttii, followed by M. braziliensis and later by M. hispida. The same trend was observed for density, except that the comparison of M. braziliensis and M. hispida did not show differences. Redundancy and canonical correspondence analysis indicated that almost all of the crustacean species were more associated with the M. harttii colonies that formed a group clearly separated from colonies of M. braziliensis and M. hispida. We also found that the internal volume of interpolyp space, only present in M. harttii, was the most important factor influencing richness and abundance of all analyzed orders of crustaceans.

Norwegian deep-water coral reefs: cultivation and molecular analysis of planktonic microbial communities.

PubMed

Jensen, Sigmund; Lynch, Michael D J; Ray, Jessica L; Neufeld, Josh D; Hovland, Martin

2015-10-01

Deep-sea coral reefs do not receive sunlight and depend on plankton. Little is known about the plankton composition at such reefs, even though they constitute habitats for many invertebrates and fish. We investigated plankton communities from three reefs at 260-350 m depth at hydrocarbon fields off the mid-Norwegian coast using a combination of cultivation and small subunit (SSU) rRNA gene and transcript sequencing. Eight months incubations of a reef water sample with minimal medium, supplemented with carbon dioxide and gaseous alkanes at in situ-like conditions, enabled isolation of mostly Alphaproteobacteria (Sulfitobacter, Loktanella), Gammaproteobacteria (Colwellia) and Flavobacteria (Polaribacter). The relative abundance of isolates in the original sample ranged from ∼ 0.01% to 0.80%. Comparisons of bacterial SSU sequences from filtered plankton of reef and non-reef control samples indicated high abundance and metabolic activity of primarily Alphaproteobacteria (SAR11 Ia), Gammaproteobacteria (ARCTIC96BD-19), but also of Deltaproteobacteria (Nitrospina, SAR324). Eukaryote SSU sequences indicated metabolically active microalgae and animals, including codfish, at the reef sites. The plankton community composition varied between reefs and differed between DNA and RNA assessments. Over 5000 operational taxonomic units were detected, some indicators of reef sites (e.g. Flavobacteria, Cercozoa, Demospongiae) and some more active at reef sites (e.g. Gammaproteobacteria, Ciliophora, Copepoda). © 2014 Society for Applied Microbiology and John Wiley & Sons Ltd.

Effects of the Veterinary Pharmaceutical Ivermectin in Indoor Aquatic Microcosms

PubMed Central

Boonstra, Harry; Reichman, Erik P.

2010-01-01

The effects of the parasiticide ivermectin were assessed in plankton-dominated indoor microcosms. Ivermectin was applied once at concentrations of 30, 100, 300, 1000, 3000, and 10,000 ng/l. The half-life (dissipation time 50%; DT50) of ivermectin in the water phase ranged from 1.1 to 8.3 days. The lowest NOECcommunity that could be derived on an isolated sampling from the microcosm study by means of multivariate techniques was 100 ng/l. The most sensitive species in the microcosm study were the cladocerans Ceriodaphnia sp. (no observed effect concentration, NOEC = 30 ng/l) and Chydorus sphaericus (NOEC = 100 ng/l). The amphipod Gammarus pulex was less sensitive to ivermectin, showing consistent statistically significant reductions at the 1000-ng/l treatment level. Copepoda taxa decreased directly after application of ivermectin in the highest treatment but had already recovered at day 20 posttreatment. Indirect effects (e.g., increase of rotifers, increased primary production) were observed at the highest treatment level starting only on day 13 of the exposure phase. Cladocera showed the highest sensitivity to ivermectin in both standard laboratory toxicity tests as well as in the microcosm study. This study demonstrates that simple plankton-dominated test systems for assessing the effects of ivermectin can produce results similar to those obtained with large complex outdoor systems. PMID:20422169

Marine bioinvasions: Differences in tropical copepod communities between inside and outside a port

NASA Astrophysics Data System (ADS)

Soares, Marcelo de Oliveira; Campos, Carolina Coelho; Santos, Nívia Maria Oliveira; Barroso, Hortência de Sousa; Mota, Erika Maria Targino; Menezes, Maria Ozilea Bezerra de; Rossi, Sergio; Garcia, Tatiane Martins

2018-04-01

The difficulty of detecting non-indigenous species (NIS) in marine environments is an "invisible problem" in areas where plankton monitoring does not occur. In this study, we investigated the dominance of the NIS Temora turbinata and copepod community structure in two tropical marine habitats: inside an offshore port, which had turbid and calm waters, and outside the port, which was more hydrodynamic. Our study area was on the northeast coast of Brazil. We found 17 taxa of Copepoda, which were dominated by T. turbinata and the congener, T. stylifera. The high average density of the NIS (21.03 ind./m3) was in stark contrast with that of the native copepods (0.01-3.27 ind./m3). The NIS density was negatively correlated with the species richness and evenness of the native community, was significantly higher inside the port than outside, and was positively correlated with phytoplankton density. A multivariate analysis revealed that there was a significant difference in copepod community structure between inside and outside the port; outside the port, the community was more diverse, and the native T. stylifera was more abundant. We found that tropical copepod communities inside an offshore port have low diversity, and probably have little biotic resistance against NIS invasions. Our results, combined with those previously obtained, highlight the need to study the spatial distributions of NIS and native species in pelagic environments.

Zooplankton variability in the subtropical estuarine system of Paranaguá Bay, Brazil, in 2012 and 2013

NASA Astrophysics Data System (ADS)

Salvador, Bianca; Bersano, José Guilherme F.

2017-12-01

Spatial and temporal dynamics of zooplankton assemblages were studied in the Paranaguá Estuarine System (southern Brazil), including data from the summer (rainy) and winter (dry) periods of 2012 and 2013. Zooplankton and environmental data were collected at 37 stations along the estuary and examined by multivariate methods. The results indicated significantly distinct assemblages; differences in abundance were the major source of variability, mainly over the temporal scale. The highest abundances were observed during rainy periods, especially in 2012, when the mean density reached 16378 ind.m-3. Winter assemblages showed lower densities but higher species diversity, due to the more extensive intrusion of coastal waters. Of the 14 taxonomic groups recorded, Copepoda was the most abundant and diverse (92% of total abundance and 22 species identified). The coastal copepods Acartia lilljeborgi (44%) and Oithona hebes (26%) were the most important species in both abundance and frequency, followed by the estuarine Pseudodiaptomus acutus and the neritic Temora turbinata. The results indicated strong influences of environmental parameters on the community structure, especially in response to seasonal variations. The spatial distribution of species was probably determined mainly by their preferences and tolerances for specific salinity conditions. On the other hand, the abundances were strongly related to higher water temperature and precipitation rates, which can drive nutrient inputs and consequently food supply in the system, due to intense continental drainage.

Taxonomy, distribution and prevalence of parasites of tigerfish, Hydrocynus vittatus (Castelnau, 1861) in the Sanyati basin, Lake Kariba, Zimbabwe.

PubMed

Mabika, Nyasha; Barson, Maxwell; Van Dyk, Cobus; Avenant-Oldewage, Annemariè

2016-09-01

Parasites of the tigerfish (Hydrocynus vittatus) were investigated in the period October 2014 to July 2015 in the Sanyati Basin, Lake Kariba. The fish were collected using seine netting and also during the annual Kariba International Tiger Fishing Tournament. A total of 80 fish specimens (24 males and 56 females) were collected and were infected with the following seven parasite taxa: Monogenea (Annulotrema sp.1 from the gills and Annulotrema sp.2 from the skin), Nematoda (Contracaecum larvae), Cestoda (bothriocephalid, larval cyclophyllid), Copepoda (Lamproglena hemprichii), pentastomid, Myxosporea (Myxobolus sp.,) and unicellular ciliate parasites (Trichodina sp., Tetrahymena sp., and unidentified). Annulotrema sp. 1 was observed in all fish and had the highest prevalence, mean intensity and abundance. The fish organs infected were gills, skin, fin, body cavity, stomach, intestines, mesentery, liver, kidney, brain cavity and swim bladder. No parasites were observed in the muscle, eyes and blood. The distribution of the parasites was highest in the gills and lowest in the brain cavity and swimbladder. Bothriocephalids, pentastomes and Trichodina sp. were not observed in male fish. Sex was not related to the intensity of parasites. The results of the study showed that H. vittatus has a richer parasite community than other previous investigated alestids. Pentastomes, Myxobolus sp., Trichodina sp., Tetrahymena sp. and bothriocephalid cestodes are new records for H. vittatus in Zimbabwe.

Distribution of Hatschekia pagellibogneravei (Copepoda: Hatschekiidae) on the gills of Pagellus bogaraveo (Teleostei: Sparidae) from Madeira, Portugal.

PubMed

Hermida, Margarida; Cruz, Cristina; Saraiva, Aurélia

2012-06-01

A population of the gill parasite Hatschekia pagellibogneravei (Hesse, 1878) was studied on one of its sparid fish hosts, the blackspot seabream, Pagellus bogaraveo (Brünnich), off the coast of Madeira Island, Portugal, northeast Atlantic. Very high infection levels of this copepod were detected, with no significant seasonal differences. Abundance was negatively correlated with fish size. There were significant differences in the distribution of this copepod among the gill arches of the host, which seem to be best explained by differences in water flow within the gill habitat.

A new species of Monstrillopsis (Crustacea, Copepoda, Monstrilloida) from the lower Northwest Passage of the Canadian Arctic.

PubMed

Delaforge, Aurélie; Suárez-Morales, Eduardo; Walkusz, Wojciech; Karley Campbell; Mundy, C J

2017-01-01

A new species of monstrilloid copepod, Monstrillopsis planifrons sp. n. , is described from an adult female that was collected beneath snow-covered sea ice during the 2014 Ice Covered Ecosystem - CAMbridge bay Process Study (ICE-CAMPS) in Dease Strait of the Canadian Arctic Archipelago. Currently, up to six species of this order are known to occur in polar latitudes. The new species described herein shares similarities with Monstrillopsis dubia (Scott, 1904) but differs in its body proportions and cephalothorax ornamentation; the cephalothorax is covered by minute scattered papillae on dorsal and ventral surfaces; this species has a reduced fifth leg endopod, fifth leg exopod armed with three setae, antennule with fused segments 3-4, and the genital double-somite bears unique posterolateral processes. This is the second species of this genus recorded in the Arctic, after Monstrillopsis ferrarii (Suárez-Morales & Ivanenko, 2004), described from the White Sea, and is the first record of Monstrillopsis in Canadian waters. With the addition of this new species and the recognition of Monstrillopsis bernardensis comb. nov. as a member of this genus, the number of nominal species is now 15. Overall, this genus has a tendency to be distributed in temperate and cold waters, while only three species have been found in tropical and subtropical latitudes.

A new species of Monstrillopsis (Crustacea, Copepoda, Monstrilloida) from the lower Northwest Passage of the Canadian Arctic

PubMed Central

Delaforge, Aurélie; Suárez-Morales, Eduardo; Walkusz, Wojciech; Karley Campbell; Mundy, C. J.

2017-01-01

Abstract A new species of monstrilloid copepod, Monstrillopsis planifrons sp. n., is described from an adult female that was collected beneath snow-covered sea ice during the 2014 Ice Covered Ecosystem – CAMbridge bay Process Study (ICE-CAMPS) in Dease Strait of the Canadian Arctic Archipelago. Currently, up to six species of this order are known to occur in polar latitudes. The new species described herein shares similarities with Monstrillopsis dubia (Scott, 1904) but differs in its body proportions and cephalothorax ornamentation; the cephalothorax is covered by minute scattered papillae on dorsal and ventral surfaces; this species has a reduced fifth leg endopod, fifth leg exopod armed with three setae, antennule with fused segments 3–4, and the genital double-somite bears unique posterolateral processes. This is the second species of this genus recorded in the Arctic, after Monstrillopsis ferrarii (Suárez-Morales & Ivanenko, 2004), described from the White Sea, and is the first record of Monstrillopsis in Canadian waters. With the addition of this new species and the recognition of Monstrillopsis bernardensis comb. nov. as a member of this genus, the number of nominal species is now 15. Overall, this genus has a tendency to be distributed in temperate and cold waters, while only three species have been found in tropical and subtropical latitudes. PMID:29118635

TLR and IMD signaling pathways from Caligus rogercresseyi (Crustacea: Copepoda): in silico gene expression and SNPs discovery.

PubMed

Valenzuela-Muñoz, V; Gallardo-Escárate, C

2014-02-01

The Toll and IMD signaling pathways represent one of the first lines of innate immune defense in invertebrates like Drosophila. However, for crustaceans like Caligus rogercresseyi, there is very little genomic information and, consequently, understanding of immune mechanisms. Massive sequencing data obtained for three developmental stages of C. rogercresseyi were used to evaluate in silico the expression patterns and presence of SNPs variants in genes involved in the Toll and IMD pathways. Through RNA-seq analysis, which used 20 contigs corresponding to relevant genes of the Toll and IMD pathways, an overexpression of genes linked to the Toll pathway, such as toll3 and Dorsal, were observed in the copepod stage. For the chalimus and adult stages, overexpression of genes in both pathways, such as Akirin and Tollip and IAP and Toll9, respectively, were observed. On the other hand, PCA statistical analysis inferred that in the chalimus and adult stages, the immune response mechanism was more developed, as evidenced by a relation between these two stages and the genes of both pathways. Moreover, 136 SNPs were identified for 20 contigs in genes of the Toll and IMD pathways. This study provides transcriptomic information about the immune response mechanisms of Caligus, thus providing a foundation for the development of new control strategies through blocking the innate immune response. Copyright © 2013 Elsevier Ltd. All rights reserved.

A new genus and species of the family Pennellidae (Copepoda, Siphonostomatoida) infecting the Pacific viperfish Chauliodus macouni

PubMed Central

Ohtsuka, Susumu; Lindsay, Dhugal J.; Izawa, Kunihiko

2018-01-01

A new genus and species of pennellid copepod, Protosarcotretes nishikawai n. g., n. sp., is described on the basis of an ovigerous female infecting a Pacific viperfish Chauliodus macouni collected from the deep-waters of Suruga Bay, Japan. The new genus exhibits the most plesiomorphic states in the first to fourth legs of pennellids, and is differentiated from two closely related pennellid genera Sarcotretes and Lernaeenicus by the morphology of the oral appendages. Two species of the genus Lernaeenicus are transferred to the new genus as Protosarcotretes multilobatus (Lewis, 1959) n. comb. and Protosarcotretes gnavus (Leigh-Sharpe, 1934) n. comb. The host specificity and life cycle of deep-sea pennellids are discussed. Sarcotretes scopeli Jungersen, 1911 and Cardiodectes bellottii (Richiardi, 1882) show low differentiated host-specificity, while P. nishikawai seems to be limited to the Stomiidae, which are rare hosts of pennellids, in contrast to the Myctophidae family. In the Pennellidae family, two patterns of the life cycle are found: with or without naupliar stages. PMID:29424341

Local and systemic gene expression responses of Atlantic salmon (Salmo salar L.) to infection with the salmon louse (Lepeophtheirus salmonis)

PubMed Central

Skugor, Stanko; Glover, Kevin Alan; Nilsen, Frank; Krasnov, Aleksei

2008-01-01

Background The salmon louse (SL) is an ectoparasitic caligid crustacean infecting salmonid fishes in the marine environment. SL represents one of the major challenges for farming of salmonids, and veterinary intervention is necessary to combat infection. This study addressed gene expression responses of Atlantic salmon infected with SL, which may account for its high susceptibility. Results The effects of SL infection on gene expression in Atlantic salmon were studied throughout the infection period from copepodids at 3 days post infection (dpi) to adult lice (33 dpi). Gene expression was analyzed at three developmental stages in damaged and intact skin, spleen, head kidney and liver, using real-time qPCR and a salmonid cDNA microarray (SFA2). Rapid detection of parasites was indicated by the up-regulation of immunoglobulins in the spleen and head kidney and IL-1 receptor type 1, CD4, beta-2-microglobulin, IL-12β, CD8α and arginase 1 in the intact skin of infected fish. Most immune responses decreased at 22 dpi, however, a second activation was observed at 33 dpi. The observed pattern of gene expression in damaged skin suggested the development of inflammation with signs of Th2-like responses. Involvement of T cells in responses to SL was witnessed with up-regulation of CD4, CD8α and programmed death ligand 1. Signs of hyporesponsive immune cells were seen. Cellular stress was prevalent in damaged skin as seen by highly significant up-regulation of heat shock proteins, other chaperones and mitochondrial proteins. Induction of the major components of extracellular matrix, TGF-β and IL-10 was observed only at the adult stage of SL. Taken together with up-regulation of matrix metalloproteinases (MMP), this classifies the wounds afflicted by SL as chronic. Overall, the gene expression changes suggest a combination of chronic stress, impaired healing and immunomodulation. Steady increase of MMP expression in all tissues except liver was a remarkable feature of SL infected fish. Conclusion SL infection in Atlantic salmon is associated with a rapid induction of mixed inflammatory responses, followed by a period of hyporesponsiveness and delayed healing of injuries. Persistent infection may lead to compromised host immunity and tissue self-destruction. PMID:18945374

Identification of 'Candidatus Piscichlamydia salmonis' in Arctic charr Salvelinus alpinus during a survey of charr production facilities in North America

USDA-ARS?s Scientific Manuscript database

Artic charr Salvelinus alpinus production facilities, nonproduction water sources and effluents in the United States and Canada were sampled to determine if chlamydiae associated with epitheliocystis were present in water and were associated with inclusions of epitheliocystis in gill tissue. Gills f...

Wild juvenile salmonids in Muchalat Inlet, British Columbia, Canada: factors associated with sea lice prevalence.

PubMed

Elmoslemany, Ahmed; Revie, Crawford W; Milligan, Barry; Stewardson, Lance; Vanderstichel, Raphael

2015-12-09

The Muchalat Inlet, British Columbia, is among the most westerly points at which aquaculture is practiced in Canada. In this paper, we summarise data from over 18000 wild fish sampled at 16 sites over an 8 yr period, between 2004 and 2011. The most prevalent wild species was chum salmon Oncorhynchus keta (82.4%), followed by Chinook O. tshawytscha (10%) and coho O. kisutch (4.3%). However, inter-annual and seasonal variation was evident, and smaller numbers of other Pacific salmon and stickleback species were sporadically observed. A high percentage of wild salmon (~95%) had no sea lice parasites present, with less than 1% of the fish hosting a mobile-stage sea louse. Of the data for which sea lice species were recorded, just over 96% of samples were identified as Lepeophtheirus salmonis. Logistic regression models assessed the association between the presence of lice and a range of independent variables. These models indicated a significant degree of spatial variation, much of which could be explained in terms of salinity levels. There were also important variations through time, both over the season within a year and across years. In addition, coho salmon were significantly more likely (odds ratio = 1.65; 95% CI = 1.20-2.3) to be infected than chum salmon. The protective effect of low salinity was most clearly seen at values lower than 15 psu, although this was dependent on fish species.

Effects of Mesocyclops longisetus (Copepoda:Cyclopidae) on mosquitoes that inhabit tires: influence of litter type, quality, and quantity.

PubMed

Schreiber, E T; Hallmon, C F; Eskridge, K M; Marten, G G

1996-12-01

A 59-week study was conducted to evaluate the impact of adult Mesocyclops longisetus populations on larval mosquito species inhabiting tires. Greater than 90% reduction of number of 1st and 2nd instars was recorded by 4 wk with 90% reduction of number of 3rd and 4th instars after 7 wk. Reduced control was noted with the onset of cooler winter water temperature. Overall. a 52% reduction in the number of 1st and 2nd instars was achieved, and a 57% reduction was noted in number of 3rd- and 4th-instar mosquito larvae. Cooler temperatures resulted in a decline of adult Mesocyclops, which resulted in reduced larval control. Significantly greater numbers of Mesocyclops adults were collected in tires with either new litter or heavy amounts of litter regardless of litter type. Lastly, litter type, either oak leaves or pine needles, did not influence mosquito reduction or abundance of Mesocyclops populations.

Complete life cycle of a pennellid Peniculus minuticaudae Shiino, 1956 (Copepoda: Siphonostomatoida) infecting cultured threadsail filefish, Stephanolepis cirrhifer.

PubMed

Ismail, Norshida; Ohtsuka, Susumu; Maran, Balu Alagar Venmathi; Tasumi, Satoshi; Zaleha, Kassim; Yamashita, Hirofumi

2013-01-01

The complete life cycle of a pennellid copepod Peniculus minuticaudae Shiino, 1956 is proposed based on the discovery of all post-embryonic stages together with the post-metamorphic adult females infecting the fins of threadsail filefish Stephanolepis cirrhifer (Monacanthidae) cultured in a fish farm at Ehime Prefecture, Japan. The hatching stage was the infective copepodid. The life cycle of P. minuticaudae consists of six stages separated by moults: the copepodid, four chalimi and adult. In this study, the adult males were observed frequently in precopulatory amplexus with various stages of females however, copulation occurs only between adults. Fertilized pre-metamorphic adult females carrying spermatophores may detach from the host and settle again before undergoing massive differential growth into the post-metamorphic adult female. Comparison of the life cycle of P. minuticaudae has been made with three known pennellids: Lernaeocera branchialis (Linnaeus, 1767), Cardiodectes medusaeus (Wilson, 1908) and Lernaeenicus sprattae (Sowerby, 1806). Among the compared species, P. minuticaudae is the first ectoparasitic pennellid to be discovered to complete its life cycle on a single host without any change in infection site preferences between infective copepodid and fertilized pre-metamorphic female. © N. Ismail et al., published by EDP Sciences, 2013.

A new species of Monocheres Stock (Copepoda, Siphonostomatoida, Asterocheridae) from shallow waters off Florida, USA: an unexpected discovery.

PubMed

Suárez-Morales, Eduardo

2016-01-01

The rare asterocherid copepod genus Monocheres, ectosymbionts of corals and sponges, contains only two species, one from Mauritius (Indian Ocean) and the other one from Brazil (western Atlantic). From the analysis of the digestive caecum contents of the benthic hesionid polychaete Hesione picta Müller, 1858, an adult female of an undescribed species of Monocheres was unexpectedly recovered; it is the third species of this rare asterocherid genus. The new species, Monocheres sergioi sp. n., has the distinctive reduction of the fifth leg as a process with a single seta. It differs from its two other congeners by several characters including the presence of an inner basipodal spine, the armature details of the third exopodal segment of leg 1, the shape of the cephalosome and pedigerous somites 3 and 4, and the ornamentation of the postero-lateral corners of the genital double-somite. The main synapomorphies include the presence of spinules along the posterior margin of the first leg coxal sclerite and the reduced, spiniform coxal seta on leg 4. The biology and feeding habits of the polychaete containing this specimen suggests that the copepod was ingested as an ectosymbiont from sponges or coral but it is also possible that it was consumed from an ophiurid echinoderm. This finding allows an expansion of the genus geographical distribution in the northwestern Atlantic. A key to the species of Monocheres is also provided.

A new species of Monocheres Stock (Copepoda, Siphonostomatoida, Asterocheridae) from shallow waters off Florida, USA: an unexpected discovery

PubMed Central

Suárez-Morales, Eduardo

2016-01-01

Abstract The rare asterocherid copepod genus Monocheres, ectosymbionts of corals and sponges, contains only two species, one from Mauritius (Indian Ocean) and the other one from Brazil (western Atlantic). From the analysis of the digestive caecum contents of the benthic hesionid polychaete Hesione picta Müller, 1858, an adult female of an undescribed species of Monocheres was unexpectedly recovered; it is the third species of this rare asterocherid genus. The new species, Monocheres sergioi sp. n., has the distinctive reduction of the fifth leg as a process with a single seta. It differs from its two other congeners by several characters including the presence of an inner basipodal spine, the armature details of the third exopodal segment of leg 1, the shape of the cephalosome and pedigerous somites 3 and 4, and the ornamentation of the postero-lateral corners of the genital double-somite. The main synapomorphies include the presence of spinules along the posterior margin of the first leg coxal sclerite and the reduced, spiniform coxal seta on leg 4. The biology and feeding habits of the polychaete containing this specimen suggests that the copepod was ingested as an ectosymbiont from sponges or coral but it is also possible that it was consumed from an ophiurid echinoderm. This finding allows an expansion of the genus geographical distribution in the northwestern Atlantic. A key to the species of Monocheres is also provided. PMID:27551233

A new species of Halicyclops (Copepoda, Cyclopoida, Cyclopidae) from a lagoon system of the Caribbean coast of Colombia

PubMed Central

Suárez-Morales, Eduardo; Fuentes-Reinés, Juan M.

2014-01-01

Abstract Plankton samples obtained from the lagoon system Laguna Navío Quebrado, in northern Colombia, yielded male and female specimens of an undescribed cyclopoid copepod of the genus Halicyclops. The new species belongs to the highly diverse and widely distributed thermophilus-complex. It closely resembles Halicyclops clarkei Herbst, 1982 from Louisiana and Halicyclops bowmani Rocha & Iliffe, 1993 from Bermuda. These species share the same armature of P1-P4EXP3, with a 3443 spine formula and the terminal antennary segment with 5 setae. However, Halicyclops gaviriai sp. n. can be separated from both Halicyclops clarkei and Halicyclops bowmani by the morphology of the anal pseudoperculum, the proportions of the fourth antennulary segment, the length of the inner basipodal spine of P1, the P1EXP/inner basipodal spine inner length ratio and the length/width ratio of the caudal rami. This is the third species of Halicyclops recorded from Colombia and the first one described from this country. With the addition of Halicyclops gaviriai sp. n., the number of species of Halicyclops known from the Neotropics increases to 19. The regional diversity of the genus is probably underestimated. PMID:25561852

Toxicity of antifouling biocides to the intertidal harpacticoid copepod Tigriopus japonicus (Crustacea, Copepoda): effects of temperature and salinity.

PubMed

Kwok, K W H; Leung, K M Y

2005-01-01

Intertidal harpacticoid copepods are commonly used in eco-toxicity tests worldwide. They predominately live in mid-high shore rock pools and often experience a wide range of temperature and salinity fluctuation. Most eco-toxicity tests are conducted at fixed temperature and salinity and thus the influence of these environmental factors on chemical toxicity is largely unknown. This study investigated the combined effect of temperature and salinity on the acute toxicity of the copepod Tigriopus japonicus against two common biocides, copper (Cu) and tributyltin (TBT) using a 2 x 3 x 4 factorial design (i.e. two temperatures: 25 and 35 degrees C; three salinities: 15.0 per thousand, 34.5 per thousand and 45.0 per thousand; three levels of the biocide plus a control). Copper sulphate and tributyltin chloride were used as the test chemicals while distilled water and acetone were utilised as solvents for Cu and TBT respectively. 96 h-LC50s of Cu and TBT were 1024 and 0.149 microg l(-1) respectively (at 25 degrees C; 34.5 per thousand) and, based on these results, nominal biocide concentrations of LC0 (i.e. control), LC30, LC50 and LC70 were employed. Analysis of Covariance using 'concentration' as the covariate and both 'temperature' and 'salinity' as fixed factors, showed a significant interaction between temperature and salinity effects for Cu, mortality increasing with temperature but decreasing with elevated salinity. A similar result was revealed for TBT. Both temperature and salinity are, therefore, important factors affecting the results of acute eco-toxicity tests using these marine copepods. We recommend that such eco-toxicity tests should be conducted at a range of environmentally realistic temperature/salinity regimes, as this will enhance the sensitivity of the test and improve the safety margin in line with the precautionary principle.

Occurrence of mitochondrial CO1 pseudogenes in Neocalanus plumchrus (Crustacea: Copepoda): Hybridization indicated by recombined nuclear mitochondrial pseudogenes

PubMed Central

Lin, Ya-Ying

2017-01-01

A portion of the mitochondrial cytochrome c oxidase I gene was sequenced using both genomic DNA and complement DNA from three planktonic copepod Neocalanus species (N. cristatus, N. plumchrus, and N. flemingeri). Small but critical sequence differences in CO1 were observed between gDNA and cDNA from N. plumchrus. Furthermore, careful observation revealed the presence of recombination between sequences in gDNA from N. plumchrus. Moreover, a chimera of the N. cristatus and N. plumchrus sequences was obtained from N. plumchrus gDNA. The observed phenomena can be best explained by the preferential amplification of the nuclear mitochondrial pseudogenes from gDNA of N. plumchrus. Two conclusions can be drawn from the observations. First, nuclear mitochondrial pseudogenes are pervasive in N. plumchrus. Second, a mating between a female N. cristatus and a male N. plumchrus produced viable offspring, which further backcrossed to a N. plumchrus individual. These observations not only demonstrate intriguing mating behavior in these species, but also emphasize the importance of careful interpretation of species marker sequences amplified from gDNA. PMID:28231343

Complete life cycle of a pennellid Peniculus minuticaudae Shiino, 1956 (Copepoda: Siphonostomatoida) infecting cultured threadsail filefish, Stephanolepis cirrhifer

PubMed Central

Ismail, Norshida; Ohtsuka, Susumu; Venmathi Maran, Balu Alagar; Tasumi, Satoshi; Zaleha, Kassim; Yamashita, Hirofumi

2013-01-01

The complete life cycle of a pennellid copepod Peniculus minuticaudae Shiino, 1956 is proposed based on the discovery of all post-embryonic stages together with the post-metamorphic adult females infecting the fins of threadsail filefish Stephanolepis cirrhifer (Monacanthidae) cultured in a fish farm at Ehime Prefecture, Japan. The hatching stage was the infective copepodid. The life cycle of P. minuticaudae consists of six stages separated by moults: the copepodid, four chalimi and adult. In this study, the adult males were observed frequently in precopulatory amplexus with various stages of females however, copulation occurs only between adults. Fertilized pre-metamorphic adult females carrying spermatophores may detach from the host and settle again before undergoing massive differential growth into the post-metamorphic adult female. Comparison of the life cycle of P. minuticaudae has been made with three known pennellids: Lernaeocera branchialis (Linnaeus, 1767), Cardiodectes medusaeus (Wilson, 1908) and Lernaeenicus sprattae (Sowerby, 1806). Among the compared species, P. minuticaudae is the first ectoparasitic pennellid to be discovered to complete its life cycle on a single host without any change in infection site preferences between infective copepodid and fertilized pre-metamorphic female. PMID:24165196

A new genus of Asterocheridae (Copepoda: Siphonostomatoida) ectoassociate of the ascidian Eudistoma vannamei Millar, 1977 (Polycitoridae) from Brazil.

PubMed

Johnsson, Rodrigo; Bahia, Cristiano; Neves, Elizabeth

2016-05-23

Asterocheres Boeck, 1860 is the largest genus of the siphonostomatoid copepod family Asterocheridae, containing 63 valid species. The genus is known for its symbiotic relationships with many marine invertebrate taxa, especially sponges, cnidarians, bryozoans, and echinoderms. Recent studies have restricted the diagnosis of this genus. Consequently, many species are now considered as species inquirendae. The present paper describes a new species living externally on the tunic of Eudistoma vannamei Millar, 1977, an endemic ascidian from Brazil. As the new species does not fit Asterocheres in the strict sense, a new genus is erected to accommodate it. Setacheres gen. nov. is characterized by its possession of two distal setae on the third endopodal segment of P3, thus differing from the distal seta and spine pattern that is deemed as diagnostic of Asterocheres. A revision and comparison of Asterocheres´ species inquirendae revealed eight species sharing the same generic characteristics and were thus reallocated as members of the new genus.

A new culture system for in situ observation of the growth and development of Eucyclops serrulatus (Copepoda: Cyclopoida)

PubMed Central

Park, Sung-Hee; Chang, Cheon-Young

2005-01-01

A practical and convenient method of rearing Eucyclops serrulatus in a microculture environment is described. A complete life cycle of E. serrulatus was maintained in a narrow space on a microscope slide glass on which a cover glass of 22 x 40 mm in size was mounted at a height of 0.8 mm. The culture medium was constituted by bottled mineral water boiled with grains of Glycine max (soybean). Chilomonas paramecium, a free-living protozoan organism, was provided as live food. Growth of nauplii hatched from eggs to the first stage of copepodite took an average of 7.7 days, and the growth of copepodite 1 to the egg-bearing adult female took an average of 20.1 days in the microculture cell with an average life time of 44.7 days. Continuous passage of copepods was successfully maintained as long as sufficient medium and food were provided. The microculture method enables an in situ microscopic observation on the growth and developmental process of helminth larvae experimentally infected to copepods as well as of copepod itself. Furthermore, it does not require anesthetization and, therefore, minimize the amount of stress exposed to copepods during the handling process. PMID:16340303

Relation between physico-chemical limnology and crustacean community in Wular Lake of Kashmir Himalaya.

PubMed

Shah, Javaid Ahmad; Pandit, Ashok K

2013-10-01

The present study scrutinizes the seasonal variation in the distribution of crustacean zooplankton in relation to physico-chemical liminology of Wular lake. Water samples were collected from five study sites during September 2010-August 2011. Remarkable spatial and temporal variations were observed among the different study sites. Among the parameters recorded water temperature showed positive correlation with pH (p<0.01) and orthophosphate (p<0.05).Transparency showed a significant negative correlation with total alkalinity (p<0.01), free carbon dioxide (p<0.01) and ammonical nitrogen (p<0.01). Crustacean zooplankton were collected by filtering 100 L lake water through a 30 microm nytal mesh and preserved in 4% formalin. A total of 42 taxa of crustacean were recorded, among them 23 species belonged to Cladocera, 16 to Copepoda and only 3 to Ostracoda. Species diversity and density depicted an abrupt up surge on the advent of warmer period (extending from March). Among the various sites a maximum of 40 species were recorded from a single biotope (site III) against the minimum of only 17 species being recorded from site I. Bray-Curtis cluster analysis showed close similarity (0.928-0.944%) between summer and autumn in terms of species diversity. Pearson correlation coefficient of the various physico-chemical parameters of water with crustacean zooplankton depicted that not only a single but multiple factors govern over the distribution and diversity of crustacean in the lake.

Metazoan parasite communities of rock cod Eleginops maclovinus along southern Chilean coast and their use as biological tags at a local spatial scale.

PubMed

Henriquez, V P; Gonzalez, M T; Licandeo, R; Carvajal, J

2011-12-01

The composition of the metazoan parasite fauna of the rock cod Eleginops maclovinus from three locations in southern Chile was compared to assess the local spatial variation of the community component of their parasitic faunas. A total of 13 108 metazoan parasites (5267 endoparasites and 7841 ectoparasites) belonging to 34 taxa were collected from 268 specimens of E. maclovinus between October 2008 and March 2009. The populations and community quantitative descriptors were estimated. Altogether, 97.4% of the fish were infected with at least one parasite taxon. The most prevalent species were Hypoechinorhynchus magellanicus (Acanthocephala), Caligus rogercresseyi, Lepeophtheirus mugiloides, Clavella adunca (Copepoda) and Similascarophis sp. (Nematoda). Five species are new records for this host: Argulus araucanus, Hirudinea gen. sp1., Hirudinea gen. sp2., Benedenia sp. and Camallanidae gen. sp. A linear discriminant analysis (LDA) showed that the metazoan parasite fauna of E. maclovinus varied qualitatively and quantitatively among three locations, with 89.7% of fish being correctly assigned to their respective locations. This suggested that parasites could be a reliable tool to discriminate individual fish from geographically close locations. There was a weak relationship between the parasite fauna and fish size and there were no accumulations of parasites in the host over time, which could be associated with ontogenetic changes of diet associated with habitat use. © 2011 The Authors. Journal of Fish Biology © 2011 The Fisheries Society of the British Isles.

Effects of 4-nonylphenol on the biota in a littoral pond ecosystem

DOE Office of Scientific and Technical Information (OSTI.GOV)

Liber, K.; Schmude, K.; O`Halloran, S.

1994-12-31

National water quality criteria for 4-nonylphenol, a surfactant precursor and metabolite, are currently being developed by the US EPA. Preliminary data from laboratory tests indicate that the criterion maximum concentration may be as low as 3--10 {mu}g/L; field data on biological effects are rare. The study presented here was designed to assess the effects of 4-nonylphenol on a natural aquatic community using a set of 18 littoral enclosures (average volume 33 m{sup 3}). The common occurrence of 4-nonylphenol in municipal and industrial discharges dictated the use of a ``chronic`` exposure scenario for this study. Test concentrations ranged from 3 tomore » 300 {mu}g/L, with applications every 48 hours for a 20 day period. This ensured a 21-day ``chronic`` exposure period and allowed sediment concentration of 4-nonylphenol to steadily increase. Survival of juvenile bluegill sunfish was reduced at 300 {mu}g/L, but not at 100, {mu}g/L; no effects on growth were noted over the 68-day assessment period. Abundance of Cladocera and Copepoda were also reduced at 300 {mu}g/L, with recovery observed within 2--4 weeks after the last nonylphenol application. Benthic macroinvertebrates, including Chironomidae, Oligochaeta, and Mollusca, were affected at 100--300 {mu}g/L, with impacts persisting for several months. The slow recovery of benthic macroinvertebrates was partially attributed to their prolonged exposure to sediment associated nonylphenol residues.« less

Evaluation of model predictions of the ecological effects of 4-nonylphenol -- before and after model refinement

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hanratty, M.P.; Liber, K.

1994-12-31

The Littoral Ecosystem Risk Assessment Model (LERAM) is a bioenergetic ecosystem effects model. It links single species toxicity data to a bioenergetic model of the trophic structure of an ecosystem in order to simulate community and ecosystem level effects of chemical stressors. LERAM was used in 1992 to simulate the ecological effects of diflubenzuron. When compared to the results from a littoral enclosure study, the model exaggerated the cascading of effects through the trophic levels of the littoral ecosystem. It was hypothesized that this could be corrected by making minor changes in the representation of the littoral food web. Twomore » refinements of the model were therefore performed: (1) the plankton and macroinvertebrate model populations [eg., predatory Copepoda, herbivorous Insecta, green phytoplankton, etc.] were changed to better represent the habitat and feeding preferences of the endemic taxa; and (2) the method for modeling the microbial degradation of detritus (and the resulting nutrient remineralization) was changed from simulating bacterial populations to simulating bacterial function. Model predictions of the ecological effects of 4-nonylphenol were made before and after these refinements. Both sets of predictions were then compared to the results from a littoral enclosure study of the ecological effects of 4-nonylphenol. The changes in the LERAM predictions were then used to determine the success of the refinements, to guide. future research, and to further define LERAM`s domain of application.« less

White spot syndrome virus epizootic in cultured Pacific white shrimp Litopenaeus vannamei (Boone) in Taiwan.

PubMed

Cheng, L; Lin, W-H; Wang, P-C; Tsai, M-A; Hsu, J-P; Chen, S-C

2013-12-01

White spot syndrome virus (WSSV) has caused significant losses in shrimp farms worldwide. Between 2004 and 2006, Pacific white shrimp Litopenaeus vannamei (Boone) were collected from 220 farms in Taiwan to determine the prevalence and impact of WSSV infection on the shrimp farm industry. Polymerase chain reaction (PCR) analysis detected WSSV in shrimp from 26% of farms. Juvenile shrimp farms had the highest infection levels (38%; 19/50 farms) and brooder shrimp farms had the lowest (5%; one of 20 farms). The average extent of infection at each farm was as follows for WSSV-positive farms: post-larvae farms, 71%; juvenile farms, 61%; subadult farms, 62%; adult farms, 49%; and brooder farms, 40%. Characteristic white spots, hypertrophied nuclei and basophilic viral inclusion bodies were found in the epithelia of gills and tail fans, appendages, cephalothorax and hepatopancreas, and virions of WSSV were observed. Of shrimp that had WSSV lesions, 100% had lesions on the cephalothorax, 96% in gills and tail fans, 91% on appendages and 17% in the hepatopancreas. WSSV was also detected in copepoda and crustaceans from the shrimp farms. Sequence comparison using the pms146 gene fragment of WSSV showed that isolates from the farms had 99.7-100% nucleotide sequence identity with four strains in the GenBank database--China (AF332093), Taiwan (AF440570 and U50923) and Thailand (AF369029). This is the first broad study of WSSV infection in L. vannamei in Taiwan. © 2013 John Wiley & Sons Ltd.

Variability of invertebrate abundance in drinking water distribution systems in the Netherlands in relation to biostability and sediment volumes.

PubMed

van Lieverloo, J Hein M; Hoogenboezem, Wim; Veenendaal, Gerrit; van der Kooij, Dick

2012-10-15

A survey of invertebrates in drinking water from treatment works, internal taps and hydrants on mains was carried out by almost all water companies in the Netherlands from September 1993 to August 1995. Aquatic sow bugs (Asellidae, 1-12 mm) and oligochaeta worms (Oligochaeta, 1-100 mm), both known to have caused rare though embarrassing consumer complaints, were found to form 98% of the mean biomass in water flushed from mains. Their numbers in the mains water ranged up to 1500 (mean 37) Asellidae m(-3) and up to 9900 (mean 135) Oligochaeta m(-3). Smaller crustaceans (0.5-2 mm) dominated the numbers in water from mains. e.g. water fleas (Cladocera and Copepoda up to 14,000 m(-3)). Common invertebrates in treated water and in tap water were Rotifera (<1 mm) and nematode worms (Nematoda, <2 mm). No Asellidae, large Oligochaeta (>5 mm) or other large invertebrates were found in 1560 samples of 200 l treated water or tap water. Large variations in invertebrate abundance were found within and between distribution systems. Of the variability of mean biomass in mains per system, 55%, 60% and 63% could statistically be explained by differences in the Biofilm Formation Rate, non-particulate organic matter and the permanganate index of the treated water of the treatment works respectively. A similar correlation was found between mean invertebrate biomass and mean sediment volumes in the distribution systems (R(2) = 52%). Copyright © 2012 Elsevier Ltd. All rights reserved.

Remarkable convergent evolution in specialized parasitic Thecostraca (Crustacea)

PubMed Central

Pérez-Losada, Marcos; Høeg, Jens T; Crandall, Keith A

2009-01-01

Background The Thecostraca are arguably the most morphologically and biologically variable group within the Crustacea, including both suspension feeders (Cirripedia: Thoracica and Acrothoracica) and parasitic forms (Cirripedia: Rhizocephala, Ascothoracida and Facetotecta). Similarities between the metamorphosis found in the Facetotecta and Rhizocephala suggests a common evolutionary origin, but until now no comprehensive study has looked at the basic evolution of these thecostracan groups. Results To this end, we collected DNA sequences from three nuclear genes [18S rRNA (2,305), 28S rRNA (2,402), Histone H3 (328)] and 41 larval characters in seven facetotectans, five ascothoracidans, three acrothoracicans, 25 rhizocephalans and 39 thoracicans (ingroup) and 12 Malacostraca and 10 Copepoda (outgroup). Maximum parsimony, maximum likelihood and Bayesian analyses showed the Facetotecta, Ascothoracida and Cirripedia each as monophyletic. The better resolved and highly supported DNA maximum likelihood and morphological-DNA Bayesian analysis trees depicted the main phylogenetic relationships within the Thecostraca as (Facetotecta, (Ascothoracida, (Acrothoracica, (Rhizocephala, Thoracica)))). Conclusion Our analyses indicate a convergent evolution of the very similar and highly reduced slug-shaped stages found during metamorphosis of both the Rhizocephala and the Facetotecta. This provides a remarkable case of convergent evolution and implies that the advanced endoparasitic mode of life known from the Rhizocephala and strongly indicated for the Facetotecta had no common origin. Future analyses are needed to determine whether the most recent common ancestor of the Thecostraca was free-living or some primitive form of ectoparasite. PMID:19374762

Risk assessment for parasites in cultures of Diplodus puntazzo (Sparidae) in the Western Mediterranean: prospects of cross infection with Sparus aurata.

PubMed

Sánchez-García, Neus; Raga, Juan Antonio; Montero, Francisco E

2014-08-29

The sharpsnout seabream Diplodus puntazzo is of interest in Mediterranean fish farming. Disease is an important problem because parasites can spread quickly in culture conditions and fish often develop high parasite burdens. Here we assess the risk that documented parasites pose to the sustainability of D. puntazzo farming. This study specifically considers metazoan and protist parasites recorded from wild and farmed D. puntazzo in scientific literature. Risk assessment studies involve the identification, characterization and qualitative quantification of the risk in question (parasitoses in this case) and the probability of establishment. We considered the parasite species which may be difficult to manage as a priority for research into potential management strategies. Those parasites which could be transmitted from cultures of gilthead seabream (Sparus aurata) were also included in this study. Four groups of parasites represented a risk to D. puntazzo farming, ranging from moderate to high: Ciliophora, Myxozoa, Monogenea and Copepoda. Three parasite species were considered high risk to D. puntazzo cultures: Amyloodinium sp., Cryptocaryon sp. and Enteromyxum leei. These species were responsible for high mortalities in cultures of these and other fish species. In addition Sparicotyle chrysophrii, Caligus ligusticus and Gnathia vorax entail a moderate risk to D. puntazzo Mediterranean farms. No important episodes have been related to caligids and isopods in Mediterranean sparids, nevertheless they should be properly managed to prevent future problems. Copyright © 2014 Elsevier B.V. All rights reserved.

Gene expression in Atlantic salmon skin in response to infection with the parasitic copepod Lepeophtheirus salmonis, cortisol implant, and their combination

PubMed Central

2012-01-01

Background The salmon louse is an ectoparasitic copepod that causes major economic losses in the aquaculture industry of Atlantic salmon. This host displays a high level of susceptibility to lice which can be accounted for by several factors including stress. In addition, the parasite itself acts as a potent stressor of the host, and outcomes of infection can depend on biotic and abiotic factors that stimulate production of cortisol. Consequently, examination of responses to infection with this parasite, in addition to stress hormone regulation in Atlantic salmon, is vital for better understanding of the host pathogen interaction. Results Atlantic salmon post smolts were organised into four experimental groups: lice + cortisol, lice + placebo, no lice + cortisol, no lice + placebo. Infection levels were equal in both treatments upon termination of the experiment. Gene expression changes in skin were assessed with 21 k oligonucleotide microarray and qPCR at the chalimus stage 18 days post infection at 9°C. The transcriptomic effects of hormone treatment were significantly greater than lice-infection induced changes. Cortisol stimulated expression of genes involved in metabolism of steroids and amino acids, chaperones, responses to oxidative stress and eicosanoid metabolism and suppressed genes related to antigen presentation, B and T cells, antiviral and inflammatory responses. Cortisol and lice equally down-regulated a large panel of motor proteins that can be important for wound contraction. Cortisol also suppressed multiple genes involved in wound healing, parts of which were activated by the parasite. Down-regulation of collagens and other structural proteins was in parallel with the induction of proteinases that degrade extracellular matrix (MMP9 and MMP13). Cortisol reduced expression of genes encoding proteins involved in formation of various tissue structures, regulators of cell differentiation and growth factors. Conclusions These results suggest that cortisol-induced stress does not affect the level of infection of Atlantic salmon with the parasite, however, it may retard repair of skin. The cortisol induced changes are in close concordance with the existing concept of wound healing cascade. PMID:22480234

'Cand. Actinochlamydia clariae' gen. nov., sp. nov., a unique intracellular bacterium causing epitheliocystis in catfish (Clarias gariepinus) in Uganda.

PubMed

Steigen, Andreas; Nylund, Are; Karlsbakk, Egil; Akoll, Peter; Fiksdal, Ingrid U; Nylund, Stian; Odong, Robinson; Plarre, Heidrun; Semyalo, Ronald; Skår, Cecilie; Watanabe, Kuninori

2013-01-01

Epitheliocystis, caused by bacteria infecting gill epithelial cells in fish, is common among a large range of fish species in both fresh- and seawater. The aquaculture industry considers epitheliocystis an important problem. It affects the welfare of the fish and the resulting gill disease may lead to mortalities. In a culture facility in Kampala, Uganda, juveniles of the African sharptooth catfish (Clarias gariepinus) was observed swimming in the surface, sometimes belly up, showing signs of respiratory problems. Histological examination of gill tissues from this fish revealed large amounts of epitheliocysts, and also presence of a few Ichthyobodo sp. and Trichodina sp. Sequencing of the epitheliocystis bacterium 16S rRNA gene shows 86.3% similarity with Candidatus Piscichlamydia salmonis causing epitheliocystis in Atlantic salmon (Salmo salar). Transmission electron microscopy showed that the morphology of the developmental stages of the bacterium is similar to that of members of the family Chlamydiaceae. The similarity of the bacterium rRNA gene sequences compared with other chlamydia-like bacteria ranged between 80.5% and 86.3%. Inclusions containing this new bacterium have tubules/channels (termed actinae) that are radiating from the inclusion membrane and opening on the cell surface or in neighbouring cells. Radiation of tubules/channels (actinae) from the inclusion membrane has never been described in any of the other members of Chlamydiales. It seems to be a completely new character and an apomorphy. We propose the name Candidatus Actinochlamydia clariae gen. nov., sp. nov. (Actinochlamydiaceae fam. nov., order Chlamydiales, phylum Chlamydiae) for this new agent causing epitheliocystis in African sharptooth catfish.

Field trials in Norway with SLICE (0.2% emamectin benzoate) for the oral treatment of sea lice infestation in farmed Atlantic salmon Salmo salar.

PubMed

Ramstad, A; Colquhoun, D J; Nordmo, R; Sutherland, I H; Simmons, R

2002-06-21

Four commercial salmon farms on the West coast of Norway were recruited to a programme of field trials in which the efficacy of SLICE (0.2% emamectin benzoate; Schering-Plough Animal Health) was compared with a commercially available product, EKTOBANN (teflubenzuron 2 g kg(-1); Skretting A/S) in treating natural sea lice Lepeophtheirus salmonis infections in Atlantic salmon Salmo salmar L. At each test site, 3 fish pens were treated with each product. In total, nearly 1.2 million first-year-class fish were included in the trial, of which approximately 561,000 received emamectin benzoate at a dosage of 50 microg kg(-1) body wt d(-1), while approximately 610,000 received teflubenzuron at a dosage of 10 mg kg(-1) body wt d(-1). Medicated feed was provided at 0.5% body wt d(-1) over 7 consecutive days. Feed containing emamectin benzoate was generally well accepted by the fish and no problems were encountered in feeding the medicated diet at the desired dose. Lice numbers were counted 2 d before and 1, 7, 14 and 21 d after commencement of treatment. While treatment with both substances rapidly reduced lice numbers, pens treated with emamectin benzoate were found to harbour significantly fewer lice 14 and 21 d post-treatment. Twenty-one days following treatment with emamectin benzoate the lice abundance was reduced on average by 94%. Limited sampling outside the main study period indicated that emamectin benzoate protects against sea-lice infestation over longer periods.

Pharmacokinetics and transcriptional effects of the anti-salmon lice drug emamectin benzoate in Atlantic salmon (Salmo salar L.)

PubMed Central

Olsvik, Pål A; Lie, Kai K; Mykkeltvedt, Eva; Samuelsen, Ole B; Petersen, Kjell; Stavrum, Anne-Kristin; Lunestad, Bjørn T

2008-01-01

Background Emamectin benzoate (EB) is a dominating pharmaceutical drug used for the treatment and control of infections by sea lice (Lepeophtheirus salmonis) on Atlantic salmon (Salmo salar L). Fish with an initial mean weight of 132 g were experimentally medicated by a standard seven-day EB treatment, and the concentrations of drug in liver, muscle and skin were examined. To investigate how EB affects Atlantic salmon transcription in liver, tissues were assessed by microarray and qPCR at 7, 14 and 35 days after the initiation of medication. Results The pharmacokinetic examination revealed highest EB concentrations in all three tissues at day 14, seven days after the end of the medication period. Only modest effects were seen on the transcriptional levels in liver, with small fold-change alterations in transcription throughout the experimental period. Gene set enrichment analysis (GSEA) indicated that EB treatment induced oxidative stress at day 7 and inflammation at day 14. The qPCR examinations showed that medication by EB significantly increased the transcription of both HSP70 and glutathione-S-transferase (GST) in liver during a period of 35 days, compared to un-treated fish, possibly via activation of enzymes involved in phase II conjugation of metabolism in the liver. Conclusion This study has shown that a standard seven-day EB treatment has only a modest effect on the transcription of genes in liver of Atlantic salmon. Based on GSEA, the medication seems to have produced a temporary oxidative stress response that might have affected protein stability and folding, followed by a secondary inflammatory response. PMID:18786259

Pharmacokinetics and transcriptional effects of the anti-salmon lice drug emamectin benzoate in Atlantic salmon (Salmo salar L.).

PubMed

Olsvik, Pål A; Lie, Kai K; Mykkeltvedt, Eva; Samuelsen, Ole B; Petersen, Kjell; Stavrum, Anne-Kristin; Lunestad, Bjørn T

2008-09-11

Emamectin benzoate (EB) is a dominating pharmaceutical drug used for the treatment and control of infections by sea lice (Lepeophtheirus salmonis) on Atlantic salmon (Salmo salar L). Fish with an initial mean weight of 132 g were experimentally medicated by a standard seven-day EB treatment, and the concentrations of drug in liver, muscle and skin were examined. To investigate how EB affects Atlantic salmon transcription in liver, tissues were assessed by microarray and qPCR at 7, 14 and 35 days after the initiation of medication. The pharmacokinetic examination revealed highest EB concentrations in all three tissues at day 14, seven days after the end of the medication period. Only modest effects were seen on the transcriptional levels in liver, with small fold-change alterations in transcription throughout the experimental period. Gene set enrichment analysis (GSEA) indicated that EB treatment induced oxidative stress at day 7 and inflammation at day 14. The qPCR examinations showed that medication by EB significantly increased the transcription of both HSP70 and glutathione-S-transferase (GST) in liver during a period of 35 days, compared to un-treated fish, possibly via activation of enzymes involved in phase II conjugation of metabolism in the liver. This study has shown that a standard seven-day EB treatment has only a modest effect on the transcription of genes in liver of Atlantic salmon. Based on GSEA, the medication seems to have produced a temporary oxidative stress response that might have affected protein stability and folding, followed by a secondary inflammatory response.

Sea lice infestations on juvenile chum and pink salmon in the Broughton Archipelago, Canada, from 2003 to 2012.

PubMed

Patanasatienkul, Thitiwan; Sanchez, Javier; Rees, Erin E; Krkosek, Martin; Jones, Simon R M; Revie, Crawford W

2013-07-22

Juvenile pink salmon Oncorhynchus gorbuscha and chum salmon O. keta were sampled by beach or purse seine to assess levels of sea lice infestation in the Knight Inlet and Broughton Archipelago regions of coastal British Columbia, Canada, during the months of March to July from 2003 to 2012. Beach seine data were analyzed for sea lice infestation that was described in terms of prevalence, abundance, intensity, and intensity per unit length. The median annual prevalence for chum was 30%, ranging from 14% (in 2008 and 2009) to 73% (in 2004), while for pink salmon, the median was 27% and ranged from 10% (in 2011) to 68% (in 2004). Annual abundance varied from 0.2 to 5 sea lice per fish with a median of 0.47 for chum and from 0.1 to 3 lice (median 0.42) for pink salmon. Annual infestation followed broadly similar trends for both chum and pink salmon. However, the abundance and intensity of Lepeophtheirus salmonis and Caligus clemensi, the 2 main sea lice species of interest, were significantly greater on chum than on pink salmon in around half of the years studied. Logistic regression with random effect was used to model prevalence of sea lice infestation for the combined beach and purse seine data. The model suggested inter-annual variation as well as a spatial clustering effect on the prevalence of sea lice infestation in both chum and pink salmon. Fish length had an effect on prevalence, although the nature of this effect differed according to host species.

Identification guide to some Diaptomid species (Crustacea, Copepoda, Calanoida, Diaptomidae) of “de la Plata” River Basin (South America)

PubMed Central

Perbiche-Neves, Gilmar; Boxshall, Geoffrey Allan; Previattelli, Daniel; Nogueira, Marcos Gomes; da Rocha, Carlos Eduardo Falavigna

2015-01-01

Abstract An identification guide is presented for species of calanoid copepod family Diaptomidae from “de la Plata” River Basin (Argentina, Brazil, Bolivia, Paraguay and Uruguay). It was based on material collected during the summer and winter of 2010 from 43 sites across the eastern part and the lower stretches of this basin, the second largest in South America and the fourth in the world. The guide contains identification keys and species diagnoses for males and females, richly supported by scanning electronic micrographs and/or line drawings of 19 species. It also includes some general remarks on the taxonomy and phylogenetic relationships of these species. The key was adjusted to be useful for these species only, with separate keys for each sex, and is the first for females of South America. One species classified herein as incertae sedis was not included in the analysis. At least ten other species have previously been recorded in the basin but were not present in our samples. This is the first attempt to compile comprehensive taxonomic information on this group of copepods in this region, and it is expected to become a useful tool for biologists and young taxonomists interested in the crustacean biota of the Neotropical region. PMID:25931959

A new genus and species of cyclopoid (Crustacea, Copepoda, Cyclopinidae) from a coastal system in the Gulf of Mexico.

PubMed

Suárez-Morales, Eduardo; Almeyda-Artigas, Roberto Javier

2015-01-01

A new, monotypic genus of the interstitial marine cyclopoid copepod family Cyclopinidae G.O. Sars, 1913 is described from male and female specimens collected at Laguna de Términos, a large coastal lagoon system in the southern Gulf of Mexico. Mexiclopina campechana gen. et sp. n. cannot be adequately placed in any extant genus within the family. It differs from other cyclopinid genera in having a unique combination of characters including: 1) absence of modified brush-like seta on the mandibular exopod; 2) maxillule exopod with stout setal elements and brush-like setae absent; 3) basis of mandible with one seta; 4) presence of a modified seta on endopod of fourth leg; 5) fifth leg exopod unsegmented, armed with three elements in the female and five in the male; 6) intercoxal sclerite of first swimming leg with two medial spiniform processes on distal margin. The new genus is monotypic and appears to be most closely related to Cyclopina Claus, 1863 and Heptnerina Ivanenko & Defaye, 2004; the new species was compared with species of Cyclopina and it resembles Cyclopina americana Herbst, 1982 and Cyclopina caissara Lotufo, 1994. This is the second record of a species of Cyclopinidae in Mexico and the first in the Gulf of Mexico; the number of cyclopinid species recorded from the Americas is now 13.

Complementary description of Ergasilus arthrosis Roberts, 1969 (Copepoda: Poecilostomatoida: Ergasilidae), a new parasite of cichlid teleosts in southeast Mexico.

PubMed

Jiménez-García, María Isabel; Suárez-Morales, Eduardo

2017-01-01

During a parasitological survey of the ichthyofauna of Lake Catemaco, a freshwater system in the Mexican State of Veracruz, the widespread copepod Ergasilus arthrosis Roberts, 1969 was recovered from two cichlid teleosts, Mayaheros urophthalmus (Günther) and Oreochromis sp. This is the first confirmed record of this copepod species outside of the United States and from Mexico; its finding as a parasite of cichlids represents an expansion of the known host range for this copepod. The local prevalence and intensity of infection of E. arthrosis was highest in M. urophthalmus. The infection prevalence of E. arthrosis on M. urophthalmus (60%) was higher than that known for other ergasilids on cichlids. Ergasilus arthrosis can be distinguished from its closest congener E. lizae Krøyer, 1863 by the morphometry of the antennary segments, the ventral ornamentation of the thoracic sclerites and by details of the antennulary setation, but also by its habitat and host preferences. Taxonomic illustrations and morphological details of the specimens examined are also provided together with comments on the variability of this species.

Host-parasite relationships and geographic distribution of Salmincola corpulentus (Copepoda: Lernaeopodidae) on bloater (Coregonus hoyi) stocks in Lake Huron

USGS Publications Warehouse

Bowen, Charles A.; Stedman, Ralph M.

1990-01-01

Examination of the branchial cavities of 8347 adult bloaters (Coregonus hoyi) collected from seven locations in Lake Huron for parasitic copepods yielded only the lernaeopodid Salmincola corpulentus; its distribution was limited to bloaters collected in the southern two-thirds of the lake. The infections were highest off Au Sable Point and on Six Fathom Bank, where 12 and 22%, of the bloaters examined were infected, respectively. All copepods seen were sexually mature females. The dorsal anterior portion of the branchial rim was the preferred site of attachment. The prevalence of S. corpulentus increased with length of the bloaters, reaching a maximum of 40% in fish longer than 330 mm; none were seen in bloaters shorter than 182 mm. The mean intensity of S. corpulentus was unusually low (1.0–1.9) for a lernaeopodid copepod and the maximum number of copepods found on a single bloater was five. Prevalences of copepods differed significantly (P < 0.05) between bloaters collected at different geographic locations, suggesting that S. corpulentus may be of value in bloater stock determination.

Selective oviposition by Aedes aegypti (Diptera: culicidae) in response to Mesocyclops longisetus (Copepoda: Cyclopoidea) under laboratory and field conditions.

PubMed

Torres-Estrada, J L; Rodríguez, M H; Cruz-López, L; Arredondo-Jimenez, J I

2001-03-01

The influence of predacious Mesocyclops longisetus Thiebaud on the selection of oviposition sites by prey Aedes aegypti (L.) was studied under laboratory and field conditions. In both cases, gravid Ae. aegypti females were significantly more attracted to ovitraps containing copepods or to ovitraps with water in which copepods were held previously than to distilled water. Monoterpene and sesquiterpene compounds including 3-carene, alpha-terpinene, alpha-copaene, alpha-longipinene, alpha-cedrene, and delta-cadinene were found in hexane extracts of copepods by gas chromatography and mass spectrometry analyses. These compounds may be responsible for attracting gravid Ae. aegypti females and may increase the number of potential prey for the copepod.

Overlooked cryptic endemism in copepods: systematics and natural history of the calanoid subgenus Occidodiaptomus Borutzky 1991 (Copepoda, Calanoida, Diaptomidae).

PubMed

Marrone, Federico; Lo Brutto, Sabrina; Hundsdoerfer, Anna K; Arculeo, Marco

2013-01-01

Our comprehension of the phylogeny and diversity of most inland-water crustaceans is currently hampered by their pronounced morphological bradytely, which contributed to the affirmation of the "Cosmopolitanism Paradigm" of freshwater taxa. However, growing evidence of the existence of cryptic diversity and molecular regionalism is available for calanoid copepods, thus stressing the need for careful morphological and molecular studies in order to soundly investigate the systematics, diversity and distribution patterns of the group. Diaptomid copepods were here chosen as model taxa, and the morphological and molecular diversity of the species belonging to the west-Mediterranean diaptomid subgenus Occidodiaptomus were investigated with the aim of comparing the patterns of morphological and molecular evolution in freshwater copepods. Three species currently lumped under the binomen Hemidiaptomus (Occidodiaptomus) ingens and two highly divergent clades within H. (O.) roubaui were distinguished, thus showing an apparent discordance between the molecular distances recorded and Occidodiaptomus morphological homogeneity, and highlighting a noteworthy decoupling between the morphological and molecular diversity in the subgenus. Current Occidodiaptomus diversity pattern is ascribed to a combined effect of ancient vicariance and recent dispersal events. It is stressed that the lack of sound calibration points for the molecular clock makes it difficult to soundly temporally frame the diversification events of interest in the taxon studied, and thus to asses the role of morphological bradytely and of accelerated molecular evolutionary rates in shaping the current diversity of the group. Copyright © 2012 Elsevier Inc. All rights reserved.

A new Setacheres (Copepoda, Siphonostomatoida, Asterocheridae) associated with Ircinia felix (Duchassaing & Michelotti) (Porifera) from Brazil.

PubMed

Borges, Camila C; Neves, Elizabeth G; Johnsson, Rodrigo

2017-12-08

Recent surveys of the copepod fauna associated with the sponge Ircinia felix (Porifera, Dictyoceratida) in Brazil resulted in the discovery of a new siphonostomatoid species belonging to a recently erected genus of Asterocheridae. Setacheres portobarrensis sp. nov. possesses a 21-segmented antennule, with 3 free distal segments, after the aesthetasc. The third exopodal segment of leg 3 shows a distal seta instead of a spine as in some other congeners. The new species shows several unique features on the third endopodal segment of the antenna, the mandibular stylet, the inner lobe of the maxillule, and setules and spinules located in specific regions of legs 1 to 4. Setacheres portobarrensis sp. nov. follows the same distributional pattern as its congeners, and this is the first record of a siphonostomatoid copepod associated with Ircinia felix.

Systematic revision of the pennellid genus Creopelates Shiino, 1958 (Copepoda: Siphonostomatoida) and the proposal of a new genus.

PubMed

Uyeno, Daisuke

2015-01-07

The parasitic copepod Creopelates floridus Shiino, 1958 (Siphonostomatoida: Pennellidae) is redescribed based on postmetamorphic adult females in the collection of the Imperial Majesty of Japan deposited in the National Museum of Nature and Science, Tsukuba (NSMT), Japan. Five new species of pennellid copepods are described based on postmetamorphic adult females from marine actinopterygian fishes newly collected in littoral waters of Japan and the Philippines, in the western North Pacific. The copepods and their hosts are as follows: Creopelates hosinoi n. sp. from Bryaninops yongei (Davis & Cohen) (Perciformes: Gobiidae); C. shirakawai n. sp. from Diancistrus fuscus (Fowler) (Ophidiiformes: Bythitidae); C. lubangenesis n. sp. from Gobiodon rivulatus (Rüppell) (Perciformes: Gobiidae); Nagasawanus akinohama n. gen. et n. sp. from Trimma grammistes (Tomiyama) (Perciformes: Gobiidae); N. snufkini n. gen. et n. sp. from T. tevegae Cohen & Davis. The total number of valid species contained in the genus Creopelates is now five. Nagasawanus n. gen. is distinguishable from other pennellid genera by the following features: antennary processes and cephalic lobes rounded without branched fringes, neck region without processes, maxilla with claw-like terminal segment lacking spinules. Keys to the genera of Pennellidae and to the species of Creopelates and Nagasawanus n. gen. are also provided.

Infestation of gill copepod Lernanthropus latis (Copepoda: Lernanthropidae) and its effect on cage-cultured Asian sea bass Lates calcarifer.

PubMed

Kua, B C; Noraziah, M R; Nik Rahimah, A R

2012-09-01

Twenty Asian sea bass Lates calcarifer from a floating cage in Bt. Tambun, Penang were examined for the presence of parasitic gill copepod, Lernanthropus latis. The prevalence of L. latis was 100% with the intensity of infection ranging from 1 to 18 parasites per host or 3.75 of mean intensity. Female parasites having oblong cephalothorax and egg-strings were seen mainly on the entire gill of examined Asian sea bass. The infected gill of Asian sea bass was pale and had eccessive mucus production. Under light and scanning electron microscopies (SEM), L. latis was seen grasping or holding tightly to the gill filament using their antenna, maxilla and maxilliped. These structures are characteristically prehensile and uncinate for the parasite to attach onto the host tissue. The damage was clearly seen under SEM as the hooked end of the antenna was embedded into the gill filament. The parasite also has the mandible which is styliform with eight teeth on the inner margin. The pathological effects such as erosion, haemorrhages, hyperplasia and necrosis along the secondary lamellae of gill filaments were seen and more severe at the attachment site. The combined actions of the antenna, maxilla and maxilliped together with the mandible resulted in extensive damage as L. latis attached and fed on the host tissues.

A new genus and species of cyclopoid (Crustacea, Copepoda, Cyclopinidae) from a coastal system in the Gulf of Mexico

PubMed Central

Suárez-Morales, Eduardo; Almeyda-Artigas, Roberto Javier

2015-01-01

Abstract A new, monotypic genus of the interstitial marine cyclopoid copepod family Cyclopinidae G.O. Sars, 1913 is described from male and female specimens collected at Laguna de Términos, a large coastal lagoon system in the southern Gulf of Mexico. Mexiclopina campechana gen. et sp. n. cannot be adequately placed in any extant genus within the family. It differs from other cyclopinid genera in having a unique combination of characters including: 1) absence of modified brush-like seta on the mandibular exopod; 2) maxillule exopod with stout setal elements and brush-like setae absent; 3) basis of mandible with one seta; 4) presence of a modified seta on endopod of fourth leg; 5) fifth leg exopod unsegmented, armed with three elements in the female and five in the male; 6) intercoxal sclerite of first swimming leg with two medial spiniform processes on distal margin. The new genus is monotypic and appears to be most closely related to Cyclopina Claus, 1863 and Heptnerina Ivanenko & Defaye, 2004; the new species was compared with species of Cyclopina and it resembles Cyclopina americana Herbst, 1982 and Cyclopina caissara Lotufo, 1994. This is the second record of a species of Cyclopinidae in Mexico and the first in the Gulf of Mexico; the number of cyclopinid species recorded from the Americas is now 13. PMID:26668545

Description of four new species and a revision of the genus Tripaphylus Richiardi in Anonymous, 1878 (Copepoda: Siphonostomatoida: Sphyriidae).

PubMed

Dippenaar, Susan M

2018-03-01

Tripaphylus Richiardi in Anonymous, 1878 is one of the genera of the Sphyriidae Wilson, 1919 and it currently accommodates ten species. Only scanty descriptions are available for the females and some males of the species. Tripaphylus specimens, described and illustrated in this paper, were collected from elasmobranch hosts off the South African coast or came from the private collection of the late Dr G. Benz. Collected specimens were fixed and preserved in 70% ethanol, examined by light - and scanning electron microscopy, and compared with the known species. Descriptions and illustrations are provided for the transformed adult females and males of T. elongatus (Wilson, 1932) and T. versicolor (Wilson, 1919) while illustrated descriptions of the transformed adult females are also provided for T. ferox (Wilson, 1919) and T. vaissierei (Delamare Deboutteville & Nuñes-Ruivo, 1954). Additionally, the material previously reported as T. ferox is considered to represent T. elongatus and that reported as T. lobatus (Kirtisinghe, 1964) is considered a junior synonym of T. vaissierei. Based on the collected material the transformed adult female and male of T. lewisi n. sp. are described as well as the adult transformed females of T. benzi n. sp., T. hoi n. sp., and T. beatricae n. sp. A summarised review of the main features is provided for each of the previously described T. musteli (van Beneden, 1851), T. hemigalei Kirtisinghe, 1964, T. australis (Kabata, 1993), T. triakis (Castro Romero, 2001) and T. asymboli (Turner, Kyne & Bennett, 2003). Furthermore, reasons are provided for the recommendation that T. hemigalei be considered a species inquirenda. An identification key to the transformed adult females of all species of Tripaphylus is provided and the host records are also updated.

Using observed load distributions with a simple model to analyse the epidemiology of sea lice (Lepeophtheirus salmonis) on sea trout (Salmo trutta).

PubMed

Murray, Alexander G

2002-06-01

Sea lice are ectoparasites of salmonids that have been associated with the recent decline in sea trout numbers in north-west Europe. Observed patterns of louse load distribution between sea trout in the seas surrounding the UK, Ireland and Norway and a simple model have been used to analyse the epidemiology of lice. Loads are aggregated and deviate strongly from the Poisson distribution, although less than is observed with many other parasites. The louse numbers on fish from offshore sites are slightly less variable than for fish from coastal sites with comparable mean loads. Analysis of louse development stages and sexes shows that selection between hosts by sea lice plays a limited role. If host selection is absent, then associated poor condition would be caused by, not the cause of, high louse burdens; however the absence of such selection is not proved. Scenarios with infection that is patchy in space and time best generate the aggregated load patterns observed; these patches accord with observed swarms of copepodids. Prevalence patterns may indicate the movement of trout between environments. Control of copepodids in infection 'hot spots', either directly or through control of louse egg production in their catchment, may reduce louse loads on wild sea trout and, in particular, extreme and damaging loads.

Diversity and distribution of heterotrophic dinoflagellates from the coastal waters of Port Blair, South Andaman.

PubMed

Sai Elangovan, S; Padmavati, G

2017-11-06

The interaction between the environment and heterotrophic dinoflagellates inhabiting coastal waters of South Andaman was studied based on year round collections made during September 2012-August 2013 in the bay, eastern, and western region of South Andaman. The distribution pattern of microzooplankton in South Andaman showed high abundance in eutrophic waters (bay region) and gradually decreased towards the off shore region. Microzooplankton community comprised of six different taxa, viz. tintinnids, heterotrophic dinoflagellates, non-loricate ciliates, Foraminifera, Rotifera, and Copepoda (nauplii). Tintinnids were the major component of the microzooplankton (43.8 ± 7%) followed by heterotrophic dinoflagellates (34 ± 12%) and copepod nauplii (18.8 ± 4.0%). This study focused on heterotrophic dinoflagellates which ranked next to tintinnids in overall abundance and contributed 38-42% in the bay, 22-37% in the eastern, and 15-29% in the western region to the microzooplankton community. Dinoflagellates showed a positive correlation with salinity and a negative correlation with dissolved oxygen and chlorophyll a (r = - 0.3). Abundance of heterotrophic dinoflagellates in this area may be due to their diverse and advantageous mode of nutrition. A total of 35 species belonging to 8 genera of heterotrophic dinoflagellates were recorded during the study period. Heterotrophic dinoflagellates showed a great potential to thrive in low oxygenated and low productive area (p < 0.001, Mann-Whitney test). Relatively higher diversity (H') in the dinoflagellates population was found in the bay region (avg. H' = 3.46).

The Application of DNA Barcodes for the Identification of Marine Crustaceans from the North Sea and Adjacent Regions

PubMed Central

Raupach, Michael J.; Barco, Andrea; Steinke, Dirk; Beermann, Jan; Laakmann, Silke; Mohrbeck, Inga; Neumann, Hermann; Kihara, Terue C.; Pointner, Karin; Radulovici, Adriana; Segelken-Voigt, Alexandra; Wesse, Christina; Knebelsberger, Thomas

2015-01-01

During the last years DNA barcoding has become a popular method of choice for molecular specimen identification. Here we present a comprehensive DNA barcode library of various crustacean taxa found in the North Sea, one of the most extensively studied marine regions of the world. Our data set includes 1,332 barcodes covering 205 species, including taxa of the Amphipoda, Copepoda, Decapoda, Isopoda, Thecostraca, and others. This dataset represents the most extensive DNA barcode library of the Crustacea in terms of species number to date. By using the Barcode of Life Data Systems (BOLD), unique BINs were identified for 198 (96.6%) of the analyzed species. Six species were characterized by two BINs (2.9%), and three BINs were found for the amphipod species Gammarus salinus Spooner, 1947 (0.4%). Intraspecific distances with values higher than 2.2% were revealed for 13 species (6.3%). Exceptionally high distances of up to 14.87% between two distinct but monophyletic clusters were found for the parasitic copepod Caligus elongatus Nordmann, 1832, supporting the results of previous studies that indicated the existence of an overlooked sea louse species. In contrast to these high distances, haplotype-sharing was observed for two decapod spider crab species, Macropodia parva Van Noort & Adema, 1985 and Macropodia rostrata (Linnaeus, 1761), underlining the need for a taxonomic revision of both species. Summarizing the results, our study confirms the application of DNA barcodes as highly effective identification system for the analyzed marine crustaceans of the North Sea and represents an important milestone for modern biodiversity assessment studies using barcode sequences. PMID:26417993

Diet variability of forage fishes in the Northern California Current System

NASA Astrophysics Data System (ADS)

Hill, Andrew D.; Daly, Elizabeth A.; Brodeur, Richard D.

2015-06-01

As fisheries management shifts to an ecosystem-based approach, understanding energy pathways and trophic relationships in the Northern California Current (NCC) will become increasingly important for predictive modeling and understanding ecosystem response to changing ocean conditions. In the NCC, pelagic forage fishes are a critical link between seasonal and interannual variation in primary production and upper trophic groups. We compared diets among dominant forage fish (sardines, anchovies, herring, and smelts) in the NCC collected in May and June of 2011 and June 2012, and found high diet variability between and within species on seasonal and annual time scales, and also on decadal scales when compared to results of past studies conducted in the early 2000s. Copepoda were a large proportion by weight of several forage fish diets in 2011 and 2012, which differed from a preponderance of Euphausiidae found in previous studies, even though all years exhibited cool ocean conditions. We also examined diet overlap among these species and with co-occurring subyearling Chinook salmon and found that surf smelt diets overlapped more with subyearling Chinook diets than any other forage fish. Herring and sardine diets overlapped the most with each other in our interdecadal comparisons and some prey items were common to all forage fish diets. Forage fish that show plasticity in diet may be more adapted to ocean conditions of low productivity or anomalous prey fields. These findings highlight the variable and not well-understood connections between ocean conditions and energy pathways within the NCC.

Zooplankton communities and Bythotrephes longimanus in lakes of the montane region of the northern Alps

PubMed Central

Horváth, Zsófia; Vad, Csaba F.; Preiler, Christian; Birtel, Julia; Matthews, Blake; Ptáčníková, Radka; Ptáčník, Robert

2017-01-01

Abstract Lakes in the Alps represent a considerable fraction of nutrient-poor lakes in Central Europe, with unique biodiversity and ecosystem properties. Although some individual lakes are well studied, less knowledge is available on large-scale patterns essential to general understanding of their functioning. Here, we aimed to describe crustacean zooplankton communities (Cladocera, Copepoda) and identify their environmental drivers in the pelagic zone of 54 oligotrophic lakes in the montane region of the Alps (400–1200 m) in Austria, Germany, and Switzerland, covering a spatial scale of 650 km. Moreover, we aimed to provide data on the distribution and ecological requirements of the North American invader Bythotrephes longimanus in its Central European native range. Communities were mainly dominated by widespread species typical of lowland habitats, and only a few true specialists of oligotrophic alpine lakes were present. The most frequent taxa were the Daphnia longispina complex and Eudiaptomus gracilis, with 48 and 45 occurrences, respectively. Species richness decreased with altitude and increased with lake area. The main structuring factors of community composition were chlorophyll a concentration and depth, which drove an apparent separation of mesotrophic and oligotrophic communities. Bythotrephes had 13 occurrences, showing a preference for deep oligotrophic lakes. Its presence was not coupled with lower crustacean species richness, as was repeatedly observed in North America. Additionally, it frequently co-occurred with the other large predatory cladoceran, Leptodora kindtii. B. longimanus might be considered a truly montane species in Central Europe, given its absence in lowland and alpine lakes. PMID:28824797

Zooplankton communities and Bythotrephes longimanus in lakes of the montane region of the northern Alps

PubMed Central

Horváth, Zsófia; Vad, Csaba F.; Preiler, Christian; Birtel, Julia; Matthews, Blake; Ptáčníková, Radka; Ptacnik, Robert

2017-01-01

Lakes in the Alps represent a considerable fraction of nutrient-poor lakes in Central Europe, with unique biodiversity and ecosystem properties. Although some individual lakes are well-studied, less knowledge is available on large-scale patterns essential to generalise the understanding of their functioning. Here, we aimed to describe crustacean zooplankton communities (Cladocera, Copepoda) and identify their environmental drivers in the pelagic zone of 54 oligotrophic lakes in the montane region of the Alps (400–1200 m) in Austria, Germany, and Switzerland, covering a spatial scale of 650 km. Moreover, we aimed to provide data on the distribution and ecological requirements of the North American invader Bytotrephes longimanus in its Central European native range. Communities were mainly dominated by widespread species typical of lowland habitats, and only a few true specialists of oligotrophic alpine lakes were present. The most frequent taxa were the Daphnia longispina complex and Eudiaptomus gracilis, with 48 and 45 occurrences, respectively. Species richness decreased with altitude and increased with lake area. The main structuring factors of community composition were chlorophyll a concentration and depth, which drove an apparent separation of mesotrophic and oligotrophic communities. Bytotrephes had 13 occurrences, showing a preference for deep oligotrophic lakes. Its presence was not coupled with lower crustacean species richness as it was repeatedly observed in North America. Additionally, it frequently co-occurred with the other large predatory cladoceran, Leptodora kindtii. B. longimanus might be considered a truly montane species in Central Europe, given its absence in lowland and alpine lakes. PMID:28649318

The mitochondrial genomes of Amphiascoides atopus and Schizopera knabeni (Harpacticoida: Miraciidae) reveal similarities between the copepod orders Harpacticoida and Poecilostomatoida.

PubMed

Easton, Erin E; Darrow, Emily M; Spears, Trisha; Thistle, David

2014-03-15

Members of subclass Copepoda are abundant, diverse, and-as a result of their variety of ecological roles in marine and freshwater environments-important, but their phylogenetic interrelationships are unclear. Recent studies of arthropods have used gene arrangements in the mitochondrial (mt) genome to infer phylogenies, but for copepods, only seven complete mt genomes have been published. These data revealed several within-order and few among-order similarities. To increase the data available for comparisons, we sequenced the complete mt genome (13,831base pairs) of Amphiascoides atopus and 10,649base pairs of the mt genome of Schizopera knabeni (both in the family Miraciidae of the order Harpacticoida). Comparison of our data to those for Tigriopus japonicus (family Harpacticidae, order Harpacticoida) revealed similarities in gene arrangement among these three species that were consistent with those found within and among families of other copepod orders. Comparison of the mt genomes of our species with those known from other copepod orders revealed the arrangement of mt genes of our Harpacticoida species to be more similar to that of Sinergasilus polycolpus (order Poecilostomatoida) than to that of T. japonicus. The similarities between S. polycolpus and our species are the first to be noted across the boundaries of copepod orders and support the possibility that mt-gene arrangement might be used to infer copepod phylogenies. We also found that our two species had extremely truncated transfer RNAs and that gene overlaps occurred much more frequently than has been reported for other copepod mt genomes. Published by Elsevier B.V.

The Application of DNA Barcodes for the Identification of Marine Crustaceans from the North Sea and Adjacent Regions.

PubMed

Raupach, Michael J; Barco, Andrea; Steinke, Dirk; Beermann, Jan; Laakmann, Silke; Mohrbeck, Inga; Neumann, Hermann; Kihara, Terue C; Pointner, Karin; Radulovici, Adriana; Segelken-Voigt, Alexandra; Wesse, Christina; Knebelsberger, Thomas

2015-01-01

During the last years DNA barcoding has become a popular method of choice for molecular specimen identification. Here we present a comprehensive DNA barcode library of various crustacean taxa found in the North Sea, one of the most extensively studied marine regions of the world. Our data set includes 1,332 barcodes covering 205 species, including taxa of the Amphipoda, Copepoda, Decapoda, Isopoda, Thecostraca, and others. This dataset represents the most extensive DNA barcode library of the Crustacea in terms of species number to date. By using the Barcode of Life Data Systems (BOLD), unique BINs were identified for 198 (96.6%) of the analyzed species. Six species were characterized by two BINs (2.9%), and three BINs were found for the amphipod species Gammarus salinus Spooner, 1947 (0.4%). Intraspecific distances with values higher than 2.2% were revealed for 13 species (6.3%). Exceptionally high distances of up to 14.87% between two distinct but monophyletic clusters were found for the parasitic copepod Caligus elongatus Nordmann, 1832, supporting the results of previous studies that indicated the existence of an overlooked sea louse species. In contrast to these high distances, haplotype-sharing was observed for two decapod spider crab species, Macropodia parva Van Noort & Adema, 1985 and Macropodia rostrata (Linnaeus, 1761), underlining the need for a taxonomic revision of both species. Summarizing the results, our study confirms the application of DNA barcodes as highly effective identification system for the analyzed marine crustaceans of the North Sea and represents an important milestone for modern biodiversity assessment studies using barcode sequences.

Temperature gradient affects differentiation of gene expression and SNP allele frequencies in the dominant Lake Baikal zooplankton species.

PubMed

Bowman, Larry L; Kondrateva, Elizaveta S; Timofeyev, Maxim A; Yampolsky, Lev Y

2018-06-01

Local adaptation and phenotypic plasticity are main mechanisms of organisms' resilience in changing environments. Both are affected by gene flow and are expected to be weak in zooplankton populations inhabiting large continuous water bodies and strongly affected by currents. Lake Baikal, the deepest and one of the coldest lakes on Earth, experienced epilimnion temperature increase during the last 100 years, exposing Baikal's zooplankton to novel selective pressures. We obtained a partial transcriptome of Epischura baikalensis (Copepoda: Calanoida), the dominant component of Baikal's zooplankton, and estimated SNP allele frequencies and transcript abundances in samples from regions of Baikal that differ in multiyear average surface temperatures. The strongest signal in both SNP and transcript abundance differentiation is the SW-NE gradient along the 600+ km long axis of the lake, suggesting isolation by distance. SNP differentiation is stronger for nonsynonymous than synonymous SNPs and is paralleled by differential survival during a laboratory exposure to increased temperature, indicating directional selection operating on the temperature gradient. Transcript abundance, generally collinear with the SNP differentiation, shows samples from the warmest, less deep location clustering together with the southernmost samples. Differential expression is more frequent among transcripts orthologous to candidate thermal response genes previously identified in model arthropods, including genes encoding cytoskeleton proteins, heat-shock proteins, proteases, enzymes of central energy metabolism, lipid and antioxidant pathways. We conclude that the pivotal endemic zooplankton species in Lake Baikal exists under temperature-mediated selection and possesses both genetic variation and plasticity to respond to novel temperature-related environmental pressures. © 2018 John Wiley & Sons Ltd.

Lunar influence on prey availability, diet shifts and niche overlap between Engraulidae larvae in tropical mangrove creeks.

PubMed

Lima, A R A; Barletta, M

2016-10-01

The influence of the lunar cycle on prey availability, diet shifts and overlap between larval Anchovia clupeoides and Cetengraulis edentulus was evaluated in mangrove creeks of the Goiana Estuary. Copepod eggs were highly abundant in the first and last quarter, at the full moon and zoea of Ucides cordatus (Ocypodidae) in the new moon. The Engraulidae larvae fed on microcrustaceans, algae and early planktonic stages of benthic organisms. The relative importance of prey varied according to prey availability in all moon phases. Larval diets were more even in the full and new moons, when the relative importance of calanoid copepods and zoeae of U. cordatus as food items increased (index of relative importance, >80% I RI ). Mangrove creeks were very important feeding grounds for engraulid larvae during spring tides. Larval diets were more diverse in the first and last-quarter moon and included protozoeae of Caridean shrimp, larvae of Anomalocardia brasiliana (Veneridae), Isopoda, Gastropoda, ephippium of Daphnia sp. and nauplii of Cirripedia, Harpacticoidia and cyclopoid Copepoda. The last five items were not found in the creeks, suggesting feeding in the main channel. During neap tides, mangrove creeks were probably also used as refugia. These larvae are opportunistic and feed on highly available prey and both species feed on the same items, leading to high dietary overlap in all moon phases. The lunar cycle, which is related to the spring-neap tidal cycle, was the major driver of quantitative and qualitative changes in feeding of engraulid larvae on a short time scale. © 2016 The Fisheries Society of the British Isles.

Lack of host specificity of copepod crustaceans associated with mushroom corals in the Red Sea.

PubMed

Ivanenko, Viatcheslav N; Hoeksema, Bert W; Mudrova, Sofya V; Nikitin, Mikhail A; Martínez, Alejandro; Rimskaya-Korsakova, Nadezda N; Berumen, Michael L; Fontaneto, Diego

2018-06-14

The radiation of symbiotic copepods (Crustacea: Copepoda) living in association with stony corals (Cnidaria: Scleractinia) is considered host-specific and linked to the phylogenetic diversification of their hosts. However, symbiotic copepods are poorly investigated, occurrence records are mostly anecdotal, and no explicit analysis exists regarding their relationship with the hosts. Here, we analysed the occurrence of symbiotic copepods on different co-occurring and phylogenetically closely related scleractinian corals. We used an innovative approach of DNA extraction from single microscopic specimens that preserves the shape of the organisms for integrative morphological studies. The rationale of the study involved: (i) sampling of mushroom corals (Fungiidae) belonging to 13 species and eight genera on different reefs along the Saudi coastline in the Red Sea, (ii) extraction of all the associated copepods, (iii) morphological screening and identification of copepod species, (iv) use of DNA taxonomy on mitochondrial and nuclear markers to determine species boundaries for morphologically unknown copepod species, (v) reconstruction of phylogenies to understand their evolutionary relationships, and (vi) analysis of the ecological drivers of the occurrence, diversity and host specificity of the copepods. The seven species of coral-associated copepods, all new to science, did not show any statistically significant evidence of host-specificity or other pattern of ecological association. We thus suggest that, contrary to most assumptions and previous anecdotal evidence on this coral-copepod host-symbiont system, the association between copepods and their host corals is rather labile, not strict, and not phylogenetically constrained, changing our perception on evolutionary patterns and processes in symbiotic copepods. Copyright © 2018. Published by Elsevier Inc.

First results on zooplankton community composition and contamination by some persistent organic pollutants in the Gulf of Tadjoura (Djibouti).

PubMed

Boldrocchi, G; Moussa Omar, Y; Rowat, D; Bettinetti, R

2018-06-15

The Gulf of Tadjoura is located in the Horn of Africa and is widely recognized as an important site where the zooplanktivorous whale sharks seasonally aggregate from October to February. The surface zooplankton community (0-3m) was weekly sampled from November 2016 to February 2017 in two sites during the whale shark aggregation period. A total of 12 phyla were identified. Copepoda represented the most abundant and diverse group with 29 different genera, and contributed with an average of 82% of the mean zooplankton density of approximately 6600indm -3 . During the sampling period, copepods were dominated numerically by Calanoida (3600indm -3 ), followed by Poicilostomatatoida (1300indm -3 ). Within the copepods, Paracalanidae, Calanidae, Oncaeidae and Miraciidae were the most common families. The temporal trend in zooplankton biomass at both stations revealed the highest peak in December (41.3±36.4mgm -3 ), and the lowest in February (6.6±3.3mgm -3 ). As no information is available on the occurrence of legacy contaminants use and release in this area, analysis revealed the consistent presence of both DDT and PCB residues in zooplankton samples in the Gulf of Tadjoura. Total PCB ranged from approximately 110 to 637ngg -1 d.w., while total DDT from 21 to 80ngg -1 d.w. The proportion of primary DDT in the total residue was higher than DDE and DDD, which strongly suggests that the area might actually be subjected to DDT inputs of the parent compound. Copyright © 2018 Elsevier B.V. All rights reserved.

De Novo Assembly of a Transcriptome for Calanus finmarchicus (Crustacea, Copepoda) – The Dominant Zooplankter of the North Atlantic Ocean

PubMed Central

Lenz, Petra H.; Roncalli, Vittoria; Hassett, R. Patrick; Wu, Le-Shin; Cieslak, Matthew C.; Hartline, Daniel K.; Christie, Andrew E.

2014-01-01

Assessing the impact of global warming on the food web of the North Atlantic will require difficult-to-obtain physiological data on a key copepod crustacean, Calanus finmarchicus. The de novo transcriptome presented here represents a new resource for acquiring such data. It was produced from multiplexed gene libraries using RNA collected from six developmental stages: embryo, early nauplius (NI-II), late nauplius (NV-VI), early copepodite (CI-II), late copepodite (CV) and adult (CVI) female. Over 400,000,000 paired-end reads (100 base-pairs long) were sequenced on an Illumina instrument, and assembled into 206,041 contigs using Trinity software. Coverage was estimated to be at least 65%. A reference transcriptome comprising 96,090 unique components (“comps”) was annotated using Blast2GO. 40% of the comps had significant blast hits. 11% of the comps were successfully annotated with gene ontology (GO) terms. Expression of many comps was found to be near zero in one or more developmental stages suggesting that 35 to 48% of the transcriptome is “silent” at any given life stage. Transcripts involved in lipid biosynthesis pathways, critical for the C. finmarchicus life cycle, were identified and their expression pattern during development was examined. Relative expression of three transcripts suggests wax ester biosynthesis in late copepodites, but triacylglyceride biosynthesis in adult females. Two of these transcripts may be involved in the preparatory phase of diapause. A key environmental challenge for C. finmarchicus is the seasonal exposure to the dinoflagellate Alexandrium fundyense with high concentrations of saxitoxins, neurotoxins that block voltage-gated sodium channels. Multiple contigs encoding putative voltage-gated sodium channels were identified. They appeared to be the result of both alternate splicing and gene duplication. This is the first report of multiple NaV1 genes in a protostome. These data provide new insights into the transcriptome and physiology of this environmentally important zooplankter. PMID:24586345

A new species of Mastigodiaptomus Light, 1939 from Mexico, with notes of species diversity of the genus (Copepoda, Calanoida, Diaptomidae)

PubMed Central

Gutiérrez-Aguirre, Martha Angélica; Cervantes-Martínez, Adrián

2016-01-01

Abstract A new species of the genus Mastigodiaptomus Light, 1939, named Mastigodiaptomus cuneatus sp. n. was found in a freshwater system in the City of Mazatlán, in the northern region of Mexico. Morphologically, the females of this new species are distinguishable from those of its congeners by the following combination of features: the right distal corner of the genital double-somite and second urosomite have a wedge-shaped projection, the fourth urosomite has no dorsal projection and its integument is smooth. The males are distinct by the following features: the right caudal ramus has a wedge-shaped structure at the disto-ventral inner corner; the basis of the right fifth leg has one triangular and one rounded projection at the distal and proximal margins, respectively, plus one hyaline membrane on the caudal surface close to the inner margin; the aculeus length is almost the width of the right second exopod (Exp2); and the frontal and caudal surfaces of the right Exp2 are smooth. Furthermore, the analysis of the COI gene of Mastigodiaptomus cuneatus sp. n. has revealed that Mastigodiaptomus albuquerquensis (Herrick, 1895) is its nearest congener, with 18.64% of genetic distance. A key for the identification of the known species of the genus is provided. PMID:28138275

Egg production and hatching success of Paracartia grani (Copepoda, Calanoida, Acartiidae) in two hypersaline ponds of a Tunisian Solar Saltern

NASA Astrophysics Data System (ADS)

Annabi-Trabelsi, Neila; Rebai, Rayda Kobbi; Ali, Mohammad; Subrahmanyam, M. N. V.; Belmonte, Genuario; Ayadi, Habib

2018-04-01

Reproductive traits of Paracartia grani [percentage of spawning females, egg production rate (EPR), and hatching success (HS)] were investigated for the first time at high salinities (39-121 psu) to examine the impact of such a particular situation. The study was done in two hypersaline ponds [A1 (39-46 psu) and C31 (70-121 psu)] in Sfax Solar Saltern, central-eastern coast of Tunisia. These ponds also differed in terms of the composition and concentrations of nutritional parameters. The EPR differed significantly between the ponds (ANOVA, F = 29.45, p < 0.001). In pond A1, EPR varied between 12.7 ± 1.3 eggs female- 1 day- 1 (7 December 2009) and 14 ± 1 eggs female- 1 day- 1 (19 January 2010) with an average of 13.3 ± 0.44 eggs female- 1 day- 1. HS after 48 h of incubation were significantly higher than those after 24 h. The mean values of HS after 48 h were 42.72 ± 2.58% at pond A1 and 41.67 ± 3.92% at pond C31. The two peaks of HS (after 48 h) were observed at 15 °C in pond A1 (21 December 2009, 45.18% nauplii eggs- 1) and in C31 (4 January 2010, 48.78%) at the same temperature. This study confirms that a broad salinity tolerance allows P. grani to settle itself in environments, which are normally hostile to the development of other Acartiidae.

Reconstruction of arietellid copepod phylogenetic relationship, with description of a new species of Sarsarietellus (Copepoda, Calanoida, Arietellidae) from Korean waters.

PubMed

Soh, Ho Young; Moon, Seong Yong; Ohtsuka, Susumu; Pae, Se Jin; Jeong, Hyeon Gyeong

2013-11-01

A new species of the genus Sarsarietellus from Korean waters, S. orientalis n. sp. is described based on both sexes. This is very closely related to S. suluensis Ohtsuka, Nishida and Machida, 2005 , but is readily distinguished by the following characteristics: in the female (1) narrow head; (2) nearly symmetrical posterior corners of last pedigerous somite, not extending beyond the genital double-somite; (3) antennary endopod slightly longer than the exopod; (4) nearly equal length of three outer spines and the terminal spine of the exopod of the fifth leg, except for the proximal third outer spine; and in the male the left fifth leg with two whip-like setae on the tip of the second exopodal segment not being rotated outside. Sarsarietellus orientalis is the fourth species of the genus Sarsarietellus, while the male of Sarsarietellus species is the first reported. The habitat colonization of arietellids is reconsidered.

Histopathology of a mesoparasitic hatschekiid copepod in hospite: does Mihbaicola sakamakii (Copepoda: Siphonostomatoida: Hatschekiidae) fast within the host fish tissue?

PubMed

Hirose, Euichi; Uyeno, Daisuke

2014-08-01

Mihbaicola sakamakii is a mesoparasitic copepod that infests the branchiostegal membranes of groupers (Perciformes: Serranidae). In this study, we observed M. sakamakii within host tissue. Histologically, copepods were found enclosed inside a pouch composed of the thickened epidermis of the host, tightly encased on all sides by the host epidermal pouch wall. There were no host blood cells or other food resources in the pouch lumen. Since the host epidermis was intact and continuous, even in the vicinity of the oral region of the parasite, the copepod would not have access to the host blood in this state. However, the stomach (ampullary part of the mid gut) was filled with granular components, the majority of which were crystalloids that likely originated from fish erythrocyte hemoglobin. We supposed that the parasite drinks blood exuded from the lesion in the fish caused by copepod entry into the host tissue. Invasion of the parasite may elicit immune responses in the host, but there were no traces on the copepod of any cellular immune reactions, such as encapsulation. The array of minute protuberances on the copepod cuticle surface may be involved in avoidance of cell adhesion. After the lesion has healed, the copepod is enclosed in a tough epidermal pouch, in which it gradually digests the contents of its stomach and continues egg production.

Global phylogeography of Oithona similis s.l. (Crustacea, Copepoda, Oithonidae) - A cosmopolitan plankton species or a complex of cryptic lineages?

PubMed

Cornils, Astrid; Wend-Heckmann, Britta; Held, Christoph

2017-02-01

Traditionally, many small-sized copepod species are considered to be widespread, bipolar or cosmopolitan. However, these large-scale distribution patterns need to be re-examined in view of increasing evidence of cryptic and pseudo-cryptic speciation in pelagic copepods. Here, we present a phylogeographic study of Oithona similis s.l. populations from the Arctic Ocean, the Southern Ocean and its northern boundaries, the North Atlantic and the Mediterrranean Sea. O. similis s.l. is considered as one of the most abundant species in temperate to polar oceans and acts as an important link in the trophic network between the microbial loop and higher trophic levels such as fish larvae. Two gene fragments were analysed: the mitochondrial cytochrome oxidase c subunit I (COI), and the nuclear ribosomal 28 S genetic marker. Seven distinct, geographically delimitated, mitochondrial lineages could be identified, with divergences among the lineages ranging from 8 to 24%, thus representing most likely cryptic or pseudocryptic species within O. similis s.l. Four lineages were identified within or close to the borders of the Southern Ocean, one lineage in the Arctic Ocean and two lineages in the temperate Northern hemisphere. Surprisingly the Arctic lineage was more closely related to lineages from the Southern hemisphere than to the other lineages from the Northern hemisphere, suggesting that geographic proximity is a rather poor predictor of how closely related the clades are on a genetic level. Copyright © 2016 Elsevier Inc. All rights reserved.

New records of Ergasilus (Copepoda: Ergasilidae) in the Laurentian Great Lakes, including a lakewide review of records and host associations

USGS Publications Warehouse

Hudson, Patrick L.; Bowen, Charles A.; Stedman, Ralph M.

1994-01-01

Ergasilus nerkae was found infecting ninespine stickleback (Pungitius pungitius) in lakes Huron, Michigan, and Superior and threespine stickleback (Gasterosteus aculeatus) and round whitefish (Prosopium cylindraceum) in Lake Huron. Based upon the literature and study of archived material, we propose that E. nerkae is enzootic to the Great Lakes and that ninespine stickleback are a preferred host in Lake Huron. Prevalence of E. nerkae on ninespine stickleback increased from 17% in June to 68% in September, but mean intensity remained light. Prevalence and mean intensity increased with host length. Ergasilus luciopercarum is also reported on lake trout (Salvelinus namaycush) and largemouth bass (Micropterus salmoides) for the first time. Host-parasite records of Ergasilus spp. in North America are reviewed, biology and taxonomy are summarized, and a checklist of Great Lakes host-parasite-locality records is provided. At present, eight species of Ergasilus are known to infect 42 Great Lakes fish species.

‘Cand. Actinochlamydia clariae’ gen. nov., sp. nov., a Unique Intracellular Bacterium Causing Epitheliocystis in Catfish (Clarias gariepinus) in Uganda

PubMed Central

Steigen, Andreas; Nylund, Are; Karlsbakk, Egil; Akoll, Peter; Fiksdal, Ingrid U.; Nylund, Stian; Odong, Robinson; Plarre, Heidrun; Semyalo, Ronald; Skår, Cecilie; Watanabe, Kuninori

2013-01-01

Background and Objectives Epitheliocystis, caused by bacteria infecting gill epithelial cells in fish, is common among a large range of fish species in both fresh- and seawater. The aquaculture industry considers epitheliocystis an important problem. It affects the welfare of the fish and the resulting gill disease may lead to mortalities. In a culture facility in Kampala, Uganda, juveniles of the African sharptooth catfish (Clarias gariepinus) was observed swimming in the surface, sometimes belly up, showing signs of respiratory problems. Histological examination of gill tissues from this fish revealed large amounts of epitheliocysts, and also presence of a few Ichthyobodo sp. and Trichodina sp. Methods and Results Sequencing of the epitheliocystis bacterium 16S rRNA gene shows 86.3% similarity with Candidatus Piscichlamydia salmonis causing epitheliocystis in Atlantic salmon (Salmo salar). Transmission electron microscopy showed that the morphology of the developmental stages of the bacterium is similar to that of members of the family Chlamydiaceae. The similarity of the bacterium rRNA gene sequences compared with other chlamydia-like bacteria ranged between 80.5% and 86.3%. Inclusions containing this new bacterium have tubules/channels (termed actinae) that are radiating from the inclusion membrane and opening on the cell surface or in neighbouring cells. Conclusions Radiation of tubules/channels (actinae) from the inclusion membrane has never been described in any of the other members of Chlamydiales. It seems to be a completely new character and an apomorphy. We propose the name Candidatus Actinochlamydia clariae gen. nov., sp. nov. (Actinochlamydiaceae fam. nov., order Chlamydiales, phylum Chlamydiae) for this new agent causing epitheliocystis in African sharptooth catfish. PMID:23826156

The control of sea lice in Atlantic salmon by selective breeding.

PubMed

Gharbi, Karim; Matthews, Louise; Bron, James; Roberts, Ron; Tinch, Alan; Stear, Michael

2015-09-06

Sea lice threaten the welfare of farmed Atlantic salmon and the sustainability of fish farming across the world. Chemical treatments are the major method of control but drug resistance means that alternatives are urgently needed. Selective breeding can be a cheap and effective alternative. Here, we combine experimental trials and diagnostics to provide a practical protocol for quantifying resistance to sea lice. We then combined quantitative genetics with epidemiological modelling to make the first prediction of the response to selection, quantified in terms of reduced need for chemical treatments. We infected over 1400 young fish with Lepeophtheirus salmonis, the most important species in the Northern Hemisphere. Mechanisms of resistance were expressed early in infection. Consequently, the number of lice per fish and the ranking of families were very similar at 7 and 17 days post infection, providing a stable window for assessing susceptibility to infection. The heritability of lice numbers within this time window was moderately high at 0.3, confirming that selective breeding is viable. We combined an epidemiological model of sea lice infection and control on a salmon farm with genetic variation in susceptibility among individuals. We simulated 10 generations of selective breeding and examined the frequency of treatments needed to control infection. Our model predicted that substantially fewer chemical treatments are needed to control lice outbreaks in selected populations and chemical treatment could be unnecessary after 10 generations of selection. Selective breeding for sea lice resistance should reduce the impact of sea lice on fish health and thus substantially improve the sustainability of Atlantic salmon production. © 2015 The Author(s).

Neoechinorhynchus (Neoechinorhynchus) chimalapasensis n. sp. (Acanthocephala: Neoechinorhynchidae) from the freshwater fish Awaous banana (Valenciennes) (Gobiidae) in Mexico.

PubMed

Salgado-Maldonado, Guillermo; Caspeta-Mandujano, Juan Manuel; Martínez-Ramírez, Emilio

2010-03-01

Neoechinorhynchus (Neoechinorhynchus) chimalapasensis n. sp. (Eoacanthocephala: Neoechinorhynchidae) is described from the intestine of Awaous banana (Valenciennes) (Pisces: Gobiidae) collected in the Río Negro, a tributary in the upper Río Coatzacoalcos basin, Santa María Chimalapa, Oaxaca State, Mexico. It is the third species of Neoechinorhynchus Stiles & Hassall, 1905 described from Mexican freshwater fishes, although 36 other species are known from freshwater fishes in the Americas. Like four other species of Neoechinorhynchus from freshwater fishes in North America and Mexico, N. (N.) limi Muzzall & Buckner, 1982, (N.) rutili (Müller, 1780) Stiles & Hassall, 1905, N. (N.) salmonis Ching, 1984 and N. (N.) roseus Salgado-Maldonado, 1978, males and females of the new species are less than 20 mm in length, lack conspicuous sexual dimorphism in size, have a small proboscis of about 0.1 mm in length with the largest hooks being the anteriormost, about 30-90 microm in length and of equal size, and have subequal lemnisci, larger than the proboscis receptacle but still relatively short and, in males, generally restricted to a position considerably anterior to the testes. The new species is closest to N. (N.) roseus, but it is distinguished from it by having: (1) a slightly larger cylindrical proboscis with almost parallel sides versus a globular proboscis with a rounded tip which is shorter and somewhat wider in N. (N.) roseus; (2) smaller but robust anterior proboscis hooks that do not reach the equatorial level or extend beyond the hooks of the middle circle as in N. (N.) roseus; and (3) the female gonopore situated ventrally subterminal, as opposed to being a significant distance anteriorly to the posterior extremity in N. (N.) roseus.

Biological baseline data Youngs Bay, Oregon, 1974

DOE Office of Scientific and Technical Information (OSTI.GOV)

McMechan, K.J.; Higley, D.L.; Holton, R.L.

1975-04-01

This report presents biological baseline information gathered during the research project, Physical, Chemical and Biological Studies on Youngs Bay.'' Youngs Bay is a shallow embayment located on the south shore of the Columbia River, near Astoria, Oregon. Research on Youngs Bay was motivated by the proposed construction by Alumax Pacific Aluminum Corporation of an aluminum reduction plant at Warrenton, Oregon. The research was designed to provide biological baseline information on Youngs Bay in anticipation of potential harmful effects from plant effluents. The information collected concerns the kinds of animals found in the Youngs Bay area, and their distribution and seasonalmore » patterns of abundance. In addition, information was collected on the feeding habits of selected fish species, and on the life history and behavioral characteristics of the most abundant benthic amphipod, Corophium salmonis. Sampling was conducted at approximately three-week intervals, using commonly accepted methods of animal collection. Relatively few stations were sampled for fish, because of the need to standardize conditions of capture. Data on fish capture are reported in terms of catch-per-unit effort by a particular sampling gear at a specific station. Methods used in sampling invertebrates were generally more quantitative, and allowed sampling at a greater variety of places, as well as a valid basis for the computation of densities. Checklists of invertebrate species and fish species were developed from these samples, and are referred to throughout the report. The invertebrate checklist is more specific taxonomically than are tables reporting invertebrate densities. This is because the methods employed in identification were more precise than those used in counts. 9 refs., 27 figs., 25 tabs.« less

Meiofauna abundance and community patterns along a transatlantic transect in the Vema Fracture Zone and in the hadal zone of the Puerto Rico trench

NASA Astrophysics Data System (ADS)

Schmidt, Christina; Escobar Wolf, Kaibil; Lins, Lidia; Martínez Arbizu, Pedro; Brandt, Angelika

2018-02-01

Despite the increasing sampling effort that occurred in the deep-sea environment during the last decades, knowledge about meiofauna ecology in trenches and Fracture Zones is still scarce. Based on the lack of this information, a longitudinal transect across the Vema Fracture Zone in the North Atlantic was sampled to test whether meiofauna abundances differ between Northeast and Northwest Atlantic basins, separated by the Mid-Atlantic Ridge. Also, for examination of meiofauna depth pattern, the Puerto Rico trench floor, its upper trench slope and the Western North Atlantic abyssal were investigated. In this study, meiofauna communities were dominated by Nematoda (93%) and Copepoda (4%). The highest total abundance of meiofauna was found in the Puerto Rico trench and the lowest in the Western basin. We found significant differences between the Eastern and Western Atlantic basins, which were potentially caused by differences in current regimes. Stronger currents observed in the Western basin possibly led to the coarser sediment grain size observed in this region, and consequently to the lower abundances of the major groups found there. Besides grain size, the total abundance of meiofauna was significantly correlated with total nitrogen, total organic carbon, and water depth. Moreover, our study reveals a trend of increasing abundance of total meiofauna with increasing water depth in the Puerto Rico trench. Also, significant differences between the Western abyssal and the Puerto Rico trench were discovered. Generally, the meiofauna abundance in the investigated area decreased from East to West but increased with increasing water depth in the Puerto Rico trench. Due to funnelling of organic sediments increased food availability towards deeper regions in trenches could occur and promote higher abundance.

Food web effects of titanium dioxide nanoparticles in an outdoor freshwater mesocosm experiment.

PubMed

Jovanović, Boris; Bezirci, Gizem; Çağan, Ali Serhan; Coppens, Jan; Levi, Eti E; Oluz, Zehra; Tuncel, Eylül; Duran, Hatice; Beklioğlu, Meryem

2016-09-01

Over the course of 78 days, nine outdoor mesocosms, each with 1350 L capacity, were situated on a pontoon platform in the middle of a lake and exposed to 0 μg L(-1) TiO2, 25 μg L(-1) TiO2 or 250 μg L(-1) TiO2 nanoparticles in the form of E171 TiO2 human food additive five times a week. Mesocosms were inoculated with sediment, phytoplankton, zooplankton, macroinvertebrates, macrophytes and fish before exposure, ensuring a complete food web. Physicochemical parameters of the water, nutrient concentrations, and biomass of the taxa were monitored. Concentrations of 25 μg L(-1) TiO2 and 250 μg L(-1) TiO2 caused a reduction in available soluble reactive phosphorus in the mesocosms by 15 and 23%, respectively, but not in the amount of total phosphorus. The biomass of Rotifera was significantly reduced by 32 and 57% in the TiO2 25 μg L(-1) and TiO2 250 μg L(-1) treatments, respectively, when compared to the control; however, the biomass of the other monitored groups-Cladocera, Copepoda, phytoplankton, macrophytes, chironomids and fish-remained unaffected. In conclusion, environmentally relevant concentrations of TiO2 nanoparticles may negatively affect certain parameters and taxa of the freshwater lentic aquatic ecosystem. However, these negative effects are not significant enough to affect the overall function of the ecosystem, as there were no cascade effects leading to a major change in its trophic state or primary production.

Chronic aquatic effect assessment for the fungicide azoxystrobin.

PubMed

van Wijngaarden, Rene P A; Belgers, Dick J M; Zafar, Mazhar I; Matser, Arrienne M; Boerwinkel, Marie-Claire; Arts, Gertie H P

2014-12-01

The present study examined the ecological effects of a range of chronic exposure concentrations of the fungicide azoxystrobin in freshwater experimental systems (1270-L outdoor microcosms). Intended and environmentally relevant test concentrations of azoxystrobin were 0 µg active ingredient (a.i.)/L, 0.33 µg a.i./L, 1 µg a.i./L, 3.3 µg a.i./L, 10 µg a.i./L, and 33 µg a.i./L, kept at constant values. Responses of freshwater populations and community parameters were studied. During the 42-d experimental period, the time-weighted average concentrations of azoxystrobin ranged from 93.5% to 99.3% of intended values. Zooplankton, especially copepods and the Daphnia longispina group, were the most sensitive groups. At the population level, a consistent no-observed-effect concentration (NOEC) of 1 µg a.i./L was calculated for Copepoda. The NOEC at the zooplankton community level was 10 µg azoxystrobin/L. The principle of the European Union pesticide directive is that lower-tier regulatory acceptable concentrations (RACs) are protective of higher-tier RACs. This was tested for chronic risks from azoxystrobin. With the exception of the microcosm community chronic RAC (highest tier), all other chronic RAC values were similar to each other (0.5-1 µg a.i./L). The new and stricter first-tier species requirements of the European Union pesticide regulation (1107/2009/EC) are not protective for the most sensitive populations in the microcosm study, when based on the higher tier population RAC. In comparison, the Water Framework Directive generates environmental quality standards that are 5 to 10 times lower than the derived chronic RACs. © 2014 SETAC.

Canyon effect and seasonal variability of deep-sea organisms in the NW Mediterranean: Synchronous, year-long captures of ;swimmers; from near-bottom sediment traps in a submarine canyon and its adjacent open slope

NASA Astrophysics Data System (ADS)

Romano, C.; Flexas, M. M.; Segura, M.; Román, S.; Bahamon, N.; Gili, J. M.; Sanchez-Vidal, A.; Martin, D.

2017-11-01

Numerous organisms, including both passive sinkers and active migrators, are captured in sediment traps together with sediments. By capturing these "swimmers", the traps become an extraordinarily tool to obtain relevant information on the biodiversity and dynamics of deep-sea organisms. Here we analyze near-bottom swimmers larger than 500 μm and their fluxes collected from eight near-bottom sediment traps installed on instrumented moorings deployed nearby Blanes Canyon (BC). Our data, obtained from November 2008 to October 2009 with a sampling rate of 15 days, constitutes the first year-long, continuous time series of the whole swimmers' community collected at different traps and bottom depths (from 300 m to 1800 m) inside a submarine canyon and on its adjacent open slope (OS). The traps captured 2155 specimens belonging to 70 taxa, with Crustacea (mainly Copepoda) and Annelida Polychaeta accounting for more than 90% of the total abundance. Almost half of the identified taxa (33) were only present in BC traps, where mean annual swimmer fluxes per trap were almost one order of magnitude higher than in the OS ones. Temporal variability in swimmer fluxes was more evident in BC than in OS. Fluxes dropped in winter (in coincidence with the stormy period in the region) and remained low until the following spring. In spring, there was a switch in taxa composition, including an increase of planktonic organisms. Additionally, we report drastic effects of extreme events, such as major storms, on deep-sea fauna. The impact of such extreme events along submarine canyon systems calls to rethink the influence of climate-driven phenomena on deep-sea ecosystems and, consequently, on their living resources.

A new species of Caligus (Copepoda, Siphonostomatoida) from the plankton of the Caribbean coast of Venezuela with a key to species

PubMed Central

Suárez-Morales, Eduardo; Camisotti, Humberto; Martín, Alberto

2012-01-01

Abstract During a survey of the zooplankton community of Bahía Amuay, Venezuelan Caribbean, specimens of an undescribed species of Caligus Müller were collected. It resembles Caligus xystercus Cressey and Caligus ocyurus Cressey, both known only from the Caribbean Sea. The new species can be distinguished from these and other congeners by a combination of characters including the armature of legs 1 and 4, but mainly by its unique female genital complex. This is the first species of Caligus described from Venezuela. The species is described in full and a key to the species of the genus recorded in Venezuela is provided. PMID:22768004

Sabelliphilidae (Copepoda: Cyclopoida) associated with the tube anemone Pachycerianthus maua (Carlgren) and the horseshoe worm Phoronis australis Haswell off New Caledonia.

PubMed

Kim, Il-Hoi; Huys, Rony

2012-09-01

Examination of washings of the ceriantharian Pachycerianthus maua (Carlgren) and its phoronid symbiont Phoronis australis Haswell in New Caledonian waters revealed two species of symbiotic copepods belonging to the family Sabelliphilidae (Cyclopoida). Phoronicola spinulatus Boxshall & Humes, 1988, the only other copepod known to be associated with a phoronid and originally described from Hong Kong, was found on both the lophophore of Phoronis australis and the tentacular crown of Pachycerianthus maua. Both sexes of Phoronicola spinulatus are redescribed based on the New Caledonian material and re-examination of the type-material revealed some observational errors in the original description. Myxomolgus hoi n. sp. was exclusively found on the ceriantharian host and appears most closely related to its only known Pacific congener, M. invulgus Kim, 2001, in lacking the strong spines on antennulary segments 1-2, the presence of closely set, fine teeth along the convex margin of the mandibular blade, and the absence of a proximal bulbous protrusion along the inner margin of leg 5 exopod. Differences between both species are found in the rostrum, antennule, antenna, maxillule, leg 4, caudal rami and body size. The relatively low number of specimens of P. spinulatus recovered from washings of the lophophores (and its presence on Pachycerianthus maua) suggests that its real host is a ceriantharian rather than a phoronid. It is conceivable that both Phoronicola spinulatus and M. hoi n. sp. live and feed on/inside the mucilaginous ceriantharian tube rather than on the lophophore or tentacular crown of their respective hosts.

Prediction of the protein components of a putative Calanus finmarchicus (Crustacea, Copepoda) circadian signaling system using a de novo assembled transcriptome

PubMed Central

Christie, Andrew E.; Fontanilla, Tiana M.; Nesbit, Katherine T.; Lenz, Petra H.

2013-01-01

Diel vertical migration and seasonal diapause are critical life history events for the copepod Calanus finmarchicus. While much is known about these behaviors phenomenologically, little is known about their molecular underpinnings. Recent studies in insects suggest that some circadian genes/proteins also contribute to the establishment of seasonal diapause. Thus, it is possible that in Calanus these distinct timing regimes share some genetic components. To begin to address this possibility, we used the well-established Drosophila melanogaster circadian system as a reference for mining clock transcripts from a 200,000+ sequence Calanus transcriptome; the proteins encoded by the identified transcripts were also deduced and characterized. Sequences encoding homologs of the Drosophila core clock proteins CLOCK, CYCLE, PERIOD and TIMELESS were identified, as was one encoding CRYPTOCHROME 2, a core clock protein in ancestral insect systems, but absent in Drosophila. Calanus transcripts encoding proteins known to modulate the Drosophila core clock were also identified and characterized, e.g. CLOCKWORK ORANGE, DOUBLETIME, SHAGGY and VRILLE. Alignment and structural analyses of the deduced Calanus proteins with their Drosophila counterparts revealed extensive sequence conservation, particularly in functional domains. Interestingly, reverse BLAST analyses of these sequences against all arthropod proteins typically revealed non-Drosophila isoforms to be most similar to the Calanus queries. This, in combination with the presence of both CRYPTOCHROME 1 (a clock input pathway protein) and CRYPTOCHROME 2 in Calanus, suggests that the organization of the copepod circadian system is an ancestral one, more similar to that of insects like Danaus plexippus than to that of Drosophila. PMID:23727418

Effects of elevated carbon dioxide (CO2) concentrations on early developmental stages of the marine copepod Calanus finmarchicus Gunnerus (Copepoda: Calanoidae).

PubMed

Pedersen, Sindre Andre; Våge, Vegard Thorset; Olsen, Anders Johny; Hammer, Karen Marie; Altin, Dag

2014-01-01

Ocean acidification poses an ongoing threat to marine organisms, and early life stages are believed to be particularly sensitive. The boreal calanoid copepod Calanus finmarchicus seasonally dominates the standing stock of zooplankton in the northern North Sea and North Atlantic, and due to its size and abundance is considered an ecological key species linking energy from primary producers to higher trophic levels. To examine whether the early stages of C. finmarchicus are particularly vulnerable to elevated levels of CO2, eggs and nauplii were subjected to different levels of CO2-acidified seawater for 1 wk. The first experiment, with eggs as the starting point, revealed no marked effect on hatching success, but a significant reduction in nauplii survival during incubation at 8800 ppm CO2. In addition, a significant decrease in ontogenetic development rate during incubation at 8800 ppm CO2 was observed in this experiment. In the second experiment, where third-stage nauplii represented the starting point, no significant effects on ontogenetic development and survival following exposure to pCO2 ≥ 7700 ppm were observed. Data suggest that the two first nauplii stages, which are fed endogenously, may be more vulnerable and therefore likely to represent the "bottleneck" for this species in a more acidic ocean. However, the absence of significant effects in the most sensitive stages during exposure to 2800 ppm CO2, a level that is well above worst-case scenario predictions for year 2300 (approximately 2000 ppm CO2), suggests that this species may be generally robust to direct effects of ocean acidification.

A new species of Pseudopandarus Kirtisinghe, 1950 (Copepoda: Siphonostomatoida: Pandaridae) from sharks of the genus Squalus L. in New Caledonian waters.

PubMed

Bernot, James P; Boxshall, Geoffrey A

2017-02-01

Both sexes of a new species of pandarid copepod are described from sharks of the genus Squalus L. (Squaliformes: Squalidae). Specimens of Pseudopandarus cairae n. sp. were collected from Squalus bucephalus Last, Séret & Pogonoski and S. melanurus Fourmanoir & Rivaton in New Caledonian waters, the first parasitic copepod to be described from either host species. This is the eighth nominal species of Pseudopandarus Kirtisinghe, 1950 and the first to be described from a shark of the order Squaliformes. Pseudopandarus cairae n. sp. is easily distinguished from P. australis Cressey & Simpfendorfer, 1988, P. longus (Gnanamuthu, 1951) Cressey, 1967, and P. pelagicus Rangnekar, 1977 in having the female genital complex concealed beneath an elongate dorsal genital shield with a trilobed posterior margin. It can be distinguished from P. gracilis Kirtisinghe, 1950 and P. scyllii Yamaguti & Yamasu, 1959 by the armature of the leg 4 endopod and by the proportions of the dorsal genital shield. The new species is unique among known species of Pseudopandarus in its possession of only 1 setal element on the distal endopod segment of leg 4. In addition to describing the new species, the host associations of all species of Pseudopandarus are reviewed and observations are made regarding sexual dimorphism and mode of attachment. A key to the species considered valid is provided.

A new species of Asterocheres (Copepoda, Siphonostomatoida) with a redescription of A. complexus Stock, 1960 and A. sarsi Bandera & Conradi, 2009.

PubMed

Bandera, Eugenia; Conradi, Mercedes

2014-07-07

The present paper reviews the material of three species of Asterocheres Boeck 1859 deposited in four different Zoological European museums as part of the ongoing taxonomical revision of this genus. Asterocheres sarsi Bandera & Conradi 2009, the species described by Sars in 1915 as Ascomyzon latum (Brady 1880) and lately recognized as a distinct species by Bandera and Conradi in 2009 is fully described in this paper from material collected by Sars in Norway in 1915 and deposited in The Natural History Museum of the University of Oslo. Asterocheres complexus Stock, 1960 which has been sometimes confused with A. sarsi is redescribed from material collected by Stock in France in 1959 and deposited in the Zoological Museum of the University of Amsterdam. Furthermore, a new species, previously misidentified as A. suberitis Gieisbrecht 1897, from the Norman`s collection of The Natural History Museum of London, is described as A. eugenioi, new species. These three species, A. complexus, A. eugenioi, and A. sarsi share the general appearance of body thanks to the pointed posterolateral angle of the epimeral area of somite bearing leg 3, sometimes slightly produced into backwardly directed processes, and somite bearing leg 4 largely concealed under somite bearing leg 3.

Patterns of pair formation and mating in an ectoparasitic caligid copepod Lepeophtheirus salmonis (Krøyer 1837): implications for its sensory and mating biology

PubMed Central

Hull, M. Q.

1998-01-01

Non-invasive observations of single cohort and manipulated populations of the sealouse on laboratory-maintained salmon established the sequence of reproductive events and mating. Protandry occurs with adult male emergence synchronized with pre-adult II female emergence, the stage at which most pair formation and pre-copular guarding takes place. Male competence for pair formation and mating was achieved within 24 h of the final moult and pairing occurred according to the preference hierarchy, virgin adult females greater than pre-adult II females much greater than pre-adult I females. This hierarchy broke down when the adult male to unmated female ratio increased rapidly. Males mated successfully not only with newly moulted adult females, but also with older virgin females in which enlargement of the genital complex and premature extrusion of egg strings had occurred. Multiple mating by adult males was demonstrated and may be widespread. Significant inter-host transfer was also demonstrated. Adult males were more mobile than adult females and showed significantly more inter-host transfer. Ablation of the distal tip of the antennules significantly reduced the success of host-finding, pair formation and males' mating.

The novel isoxazoline ectoparasiticide lotilaner (Credelio™): a non-competitive antagonist specific to invertebrates γ-aminobutyric acid-gated chloride channels (GABACls).

PubMed

Rufener, Lucien; Danelli, Vanessa; Bertrand, Daniel; Sager, Heinz

2017-11-01

The isoxazolines are a novel class of parasiticides that are potent inhibitors of γ-aminobutyric acid (GABA)-gated chloride channels (GABACls) and, to a lesser extent, of inhibitory glutamate-gated chloride channels (GluCls). Lotilaner (Credelio™), a novel representative of this chemical class, is currently evaluated for its excellent ectoparasiticide properties. In this study, we investigated the molecular mode of action and pharmacology of lotilaner. We report the successful gene identification, cDNA cloning and functional expression in Xenopus oocytes of Drosohpila melanogaster (wild type and dieldrin/fipronil-resistant forms), Lepeophtheirus salmonis (an ectoparasite copepod crustacean of salmon), Rhipicephalus microplus and Canis lupus familiaris GABACls. Automated Xenopus oocyte two-electrode voltage clamp electrophysiology was used to assess GABACls functionality and to compare ion channel inhibition by lotilaner with that of established insecticides addressing GABACls as targets. In these assays, we demonstrated that lotilaner is a potent non-competitive antagonist of insects (fly) GABACls. No cross-resistance with dieldrin or fipronil resistance mutations was detected, suggesting that lotilaner might bind to a site at least partly different from the one bound by known GABACl blockers. Using co-application experiments, we observed that lotilaner antagonism differs significantly from the classical open channel blocker fipronil. We finally confirmed for the first time that isoxazoline compounds are not only powerful antagonists of GABACls of acari (ticks) but also of crustaceans (sea lice), while no activity on a dog GABA A receptor was observed up to a concentration of 10 μM. Together, these results demonstrate that lotilaner is a non-competitive antagonist specific to invertebrate's γ-aminobutyric acid-gated chloride channels (GABACls). They contribute to our understanding of the mode of action of this new ectoparasiticide compound.

Predicting the effectiveness of depth-based technologies to prevent salmon lice infection using a dispersal model.

PubMed

Samsing, Francisca; Johnsen, Ingrid; Stien, Lars Helge; Oppedal, Frode; Albretsen, Jon; Asplin, Lars; Dempster, Tim

2016-07-01

Salmon lice is one of the major parasitic problems affecting wild and farmed salmonid species. The planktonic larval stages of these marine parasites can survive for extended periods without a host and are transported long distances by water masses. Salmon lice larvae have limited swimming capacity, but can influence their horizontal transport by vertical positioning. Here, we adapted a coupled biological-physical model to calculate the distribution of farm-produced salmon lice (Lepeophtheirus salmonis) during winter in the southwest coast of Norway. We tested 4 model simulations to see which best represented empirical data from two sources: (1) observed lice infection levels reported by farms; and (2) experimental data from a vertical exposure experiment where fish were forced to swim at different depths with a lice-barrier technology. Model simulations tested were different development time to the infective stage (35 or 50°-days), with or without the presence of temperature-controlled vertical behaviour of lice early planktonic stages (naupliar stages). The best model fit occurred with a 35°-day development time to the infective stage, and temperature-controlled vertical behaviour. We applied this model to predict the effectiveness of depth-based preventive lice-barrier technologies. Both simulated and experimental data revealed that hindering fish from swimming close to the surface efficiently reduced lice infection. Moreover, while our model simulation predicted that this preventive technology is widely applicable, its effectiveness will depend on environmental conditions. Low salinity surface waters reduce the effectiveness of this technology because salmon lice avoid these conditions, and can encounter the fish as they sink deeper in the water column. Correctly parameterized and validated salmon lice dispersal models can predict the impact of preventive approaches to control this parasite and become an essential tool in lice management strategies. Copyright

Glandular kallikrein in the innate immune system of Atlantic salmon (Salmo salar).

PubMed

Haussmann, D; Figueroa, J

2011-02-15

Glandular Kallikrein is a serine-protease with trypsin-like activity and is able to generate bioactive peptides from inactive precursors. We have evaluated the presence of this protease in the different organs of the Atlantic salmon (Salmo salar). The results clearly indicate that GK and PRL are generated in the same pituitary cells based on a co-localization by confocal microscopy. Based on probed cross-reactivity between C. striata and C. carpio glandular anti-GK antibodies, we used a homologous antibody to detect the presence of GK in several salmon tissues. We have evaluated the GK expression in healthy and defied fish. P. salmonis and V. ordalii. The GK immunoreaction in organs such as leukocytes, gills and skin is considerably increased in defied fish compared to healthy fish. This increase was present in the cells of the excretory kidney and in the intercellular tissue, where the development of hematopoietic and lymphocytic lines in fish take place. One of the most interesting organs to study was the skin, bearing in mind that this is a primary barrier to all pathogens. The skin of the defied fish exhibited an increase in immunoreactivity for glandular kallikrein similar to the protease found in mucus. An immunoreactive tissue kallikrein-like protein was identified and partially separated by perfusion chromatography. Enzymatic activity of salmon muscle prokallikrein was determined before and after trypsin activation. Kallikrein activity was characterized with respect to their ability to cleave the chromogenic leaving group, p-nitroanilide, from the peptidyl kallikrein and trypsin substrate. These findings constitute a important contribution to reveal the role of kallikrein in the innate immune system of fish. Copyright © 2010 Elsevier B.V. All rights reserved.

DNA barcoding of Arctic Ocean holozooplankton for species identification and recognition

NASA Astrophysics Data System (ADS)

Bucklin, Ann; Hopcroft, Russell R.; Kosobokova, Ksenia N.; Nigro, Lisa M.; Ortman, Brian D.; Jennings, Robert M.; Sweetman, Christopher J.

2010-01-01

Zooplankton species diversity and distribution are important measures of environmental change in the Arctic Ocean, and may serve as 'rapid-responders' of climate-induced changes in this fragile ecosystem. The scarcity of taxonomists hampers detailed and up-to-date monitoring of these patterns for the rarer and more problematic species. DNA barcodes (short DNA sequences for species recognition and discovery) provide an alternative approach to accurate identification of known species, and can speed routine analysis of zooplankton samples. During 2004-2008, zooplankton samples were collected during cruises to the central Arctic Ocean and Chukchi Sea. A ˜700 base-pair region of the mitochondrial cytochrome oxidase I (mtCOI) gene was amplified and sequenced for 82 identified specimens of 41 species, including cnidarians (six hydrozoans, one scyphozoan), arthropod crustaceans (five amphipods, 24 copepods, one decapod, and one euphausiid); two chaetognaths; and one nemertean. Phylogenetic analysis used the Neighbor-Joining algorithm with Kimura-2-Parameter (K-2-P) distances, with 1000-fold bootstrapping. K-2-P genetic distances between individuals of the same species ranged from 0.0 to 0.2; genetic distances between species ranged widely from 0.1 to 0.7. The mtCOI gene tree showed monophyly (at 100% bootstrap value) for each of the 26 species for which more than one individual was analyzed. Of seven genera for which more than one species was analyzed, four were shown to be monophyletic; three genera were not resolved. At higher taxonomic levels, only the crustacean order Copepoda was resolved, with bootstrap value of 83%. The mtCOI barcodes accurately discriminated and identified known species of 10 taxonomic groups of Arctic Ocean holozooplankton. A comprehensive DNA barcode database for the estimated 300 described species of Arctic holozooplankton will allow rapid assessment of species diversity and distribution in this climate-vulnerable ocean ecosystem.

Indicator Properties of Baltic Zooplankton for Classification of Environmental Status within Marine Strategy Framework Directive.

PubMed

Gorokhova, Elena; Lehtiniemi, Maiju; Postel, Lutz; Rubene, Gunta; Amid, Callis; Lesutiene, Jurate; Uusitalo, Laura; Strake, Solvita; Demereckiene, Natalja

2016-01-01

The European Marine Strategy Framework Directive requires the EU Member States to estimate the level of anthropogenic impacts on their marine systems using 11 Descriptors. Assessing food web response to altered habitats is addressed by Descriptor 4 and its indicators, which are being developed for regional seas. However, the development of simple foodweb indicators able to assess the health of ecologically diverse, spatially variable and complex interactions is challenging. Zooplankton is a key element in marine foodwebs and thus comprise an important part of overall ecosystem health. Here, we review work on zooplankton indicator development using long-term data sets across the Baltic Sea and report the main findings. A suite of zooplankton community metrics were evaluated as putative ecological indicators that track community state in relation to Good Environmental Status (GES) criteria with regard to eutrophication and fish feeding conditions in the Baltic Sea. On the basis of an operational definition of GES, we propose mean body mass of zooplankton in the community in combination with zooplankton stock measured as either abundance or biomass to be applicable as an integrated indicator that could be used within the Descriptor 4 in the Baltic Sea. These metrics performed best in predicting zooplankton being in-GES when considering all datasets evaluated. However, some other metrics, such as copepod biomass, the contribution of copepods to the total zooplankton biomass or biomass-based Cladocera: Copepoda ratio, were equally reliable or even superior in certain basin-specific assessments. Our evaluation suggests that in several basins of the Baltic Sea, zooplankton communities currently appear to be out-of-GES, being comprised by smaller zooplankters and having lower total abundance or biomass compared to the communities during the reference conditions; however, the changes in the taxonomic structure underlying these trends vary widely across the sea basins due to

Genetic diversity among the Eurytemora affinis species complex in the Scheldt estuary and its tributaries using ISSR-PCR marker assay

NASA Astrophysics Data System (ADS)

Gasmi, S.; Ferval, M.; Pelissier, C.; D'Amico, F.; Maris, T.; Tackx, M.; Legal, L.

2014-05-01

As an estuary being restored, the Scheldt (Belgium/The Netherlands) offers an interesting setting to study the response of organisms and ecosystems to changing conditions. This study specifically deals with this with regard to the spatio-temporal distribution and possible genetic differentiation among the species complex Eurytemora affinis (copepoda, calanoida). Until the 1990s, E. affinis typically occurred downstream the Scheldt estuary (Belgium/The Netherlands). In parallel to water quality improvement, E.affinis has recently also occurred upstream the estuary and in some of the tributaries. This paper aims to assess the origin of the copepod sibling species complex E. affinis occurring upstream the Scheldt estuary through genetic characterization. Using the Inter Simple Sequence Repeat (ISSR) technique, we explored genetic pools of the E. affinis complex in three Scheldt localities (downstream, middle-estuary and upstream) and two of its tributaries. Four ISSR primers produced 75 polymorphic loci. Bayesian and hierarchical analysis revealed different but close genetic entities in both down and upstream localities. The middle-estuary individuals were genetically a composite mix of downstream and upstream populations (84% from downstream and 16% from upstream). A distinctive separation of the tributaries and the main Scheldt stream populations suggests that two fully independent genetic pools are present. It is of note that the tributaries showed a lack of genetic subdivision, that upstream and downstream E. affinis populations are closely related, and that the downstream population is most likely at the origin of the upstream one, which implies the necessity to guarantee sufficient oxygen concentration levels throughout the estuarine continuum to guarantee the presence of this species upstream. The results of the ISSR technique are discussed in comparison with genetic studies on E. affinis using COI barcoding.

Temporal and spatial distribution of the meiobenthic community in Daya Bay, South China Sea

NASA Astrophysics Data System (ADS)

Tang, L.; Li, H. X.; Yan, Y.

2012-04-01

Spatial and temporal biodiversity patterns of the meiobenthos were studied for the first time in Daya Bay, which is a tropical semi-enclosed basin located in the South China Sea. The abundance, biomass, and composition of the meiobenthos and the basic environmental factors in the bay were investigated. The following 19 taxonomic groups were represented in the meiofauna: Nematoda, Copepoda, Polychaeta, Oligochaeta, Kinorhyncha, Gastrotricha, Ostracoda, Bivalvia, Turbellaria, Nemertinea, Sipuncula, Hydroida, Amphipoda, Cumacea, Halacaroidea, Priapulida, Echinodermata, Tanaidacea, and Rotifera. Total abundance and biomass of the meiobenthos showed great spatial and temporal variation, with mean values of 993.57 ± 455.36 ind cm-2 and 690.51 ± 210.64 μg 10 cm-2, respectively. Nematodes constituted 95.60 % of the total abundance and thus had the greatest effect on meiofauna quantity and distribution, followed by copepods (1.55 %) and polychaetes (1.39 %). Meiobenthos abundance was significantly negatively correlated with water depth at stations (r=-0.747, P<0.05) and significantly negatively correlated with silt-clay content (r=-0.516, P<0.01) and medium diameter (r=-0.499, P<0.01) of the sediment. Similar results were found for correlations of biomass and abundance of nematodes with environmental parameters. Polychaete abundance was positively correlated with the bottom water temperature (r=0.456, P<0.01). Meiobenthos abundance differed significantly among seasons (P<0.05), although no significant difference among stations and the interaction of station × season was detected by two-way ANOVA. In terms of vertical distribution, most of the meiobenthos was found in the surface layer of sediment. This pattern was apparent for nematodes and copepods, but a vertical distribution pattern for polychaetes was not as obvious. Based on the biotic indices and analyses of their correlations and variance, the diversity of this community was likely to be influenced by

Ocean acidification alters zooplankton communities and increases top-down pressure of a cubozoan predator.

PubMed

Hammill, Edd; Johnson, Ellery; Atwood, Trisha B; Harianto, Januar; Hinchliffe, Charles; Calosi, Piero; Byrne, Maria

2018-01-01

The composition of local ecological communities is determined by the members of the regional community that are able to survive the abiotic and biotic conditions of a local ecosystem. Anthropogenic activities since the industrial revolution have increased atmospheric CO 2 concentrations, which have in turn decreased ocean pH and altered carbonate ion concentrations: so called ocean acidification (OA). Single-species experiments have shown how OA can dramatically affect zooplankton development, physiology and skeletal mineralization status, potentially reducing their defensive function and altering their predatory and antipredatory behaviors. This means that increased OA may indirectly alter the biotic conditions by modifying trophic interactions. We investigated how OA affects the impact of a cubozoan predator on their zooplankton prey, predominantly Copepoda, Pleocyemata, Dendrobranchiata, and Amphipoda. Experimental conditions were set at either current (pCO 2 370 μatm) or end-of-the-century OA (pCO 2 1,100 μatm) scenarios, crossed in an orthogonal experimental design with the presence/absence of the cubozoan predator Carybdea rastoni. The combined effects of exposure to OA and predation by C. rastoni caused greater shifts in community structure, and greater reductions in the abundance of key taxa than would be predicted from combining the effect of each stressor in isolation. Specifically, we show that in the combined presence of OA and a cubozoan predator, populations of the most abundant member of the zooplankton community (calanoid copepods) were reduced 27% more than it would be predicted based on the effects of these stressors in isolation, suggesting that OA increases the susceptibility of plankton to predation. Our results indicate that the ecological consequences of OA may be greater than predicted from single-species experiments, and highlight the need to understand future marine global change from a community perspective. © 2017 John Wiley & Sons

Strong Spatial Influence on Colonization Rates in a Pioneer Zooplankton Metacommunity

PubMed Central

Frisch, Dagmar; Cottenie, Karl; Badosa, Anna; Green, Andy J.

2012-01-01

The magnitude of community-wide dispersal is central to metacommunity models, yet dispersal is notoriously difficult to quantify in passive and cryptic dispersers such as many freshwater invertebrates. By overcoming the problem of quantifying dispersal rates, colonization rates into new habitats can provide a useful estimate of the magnitude of effective dispersal. Here we study the influence of spatial and local processes on colonization rates into new ponds that indicate differential dispersal limitation of major zooplankton taxa, with important implications for metacommunity dynamics. We identify regional and local factors that affect zooplankton colonization rates and spatial patterns in a large-scale experimental system. Our study differs from others in the unique setup of the experimental pond area by which we were able to test spatial and environmental variables at a large spatial scale. We quantified colonization rates separately for the Copepoda, Cladocera and Rotifera from samples collected over a period of 21 months in 48 newly constructed temporary ponds of 0.18–2.95 ha distributed in a restored wetland area of 2,700 ha in Doñana National Park, Southern Spain. Species richness upon initial sampling of new ponds was about one third of that in reference ponds, although the rate of detection of new species from thereon were not significantly different, probably owing to high turnover in the dynamic, temporary reference ponds. Environmental heterogeneity had no detectable effect on colonization rates in new ponds. In contrast, connectivity, space (based on latitude and longitude) and surface area were key determinants of colonization rates for copepods and cladocerans. This suggests dispersal limitation in cladocerans and copepods, but not in rotifers, possibly due to differences in propagule size and abundance. PMID:22792241

Strong spatial influence on colonization rates in a pioneer zooplankton metacommunity.

PubMed

Frisch, Dagmar; Cottenie, Karl; Badosa, Anna; Green, Andy J

2012-01-01

The magnitude of community-wide dispersal is central to metacommunity models, yet dispersal is notoriously difficult to quantify in passive and cryptic dispersers such as many freshwater invertebrates. By overcoming the problem of quantifying dispersal rates, colonization rates into new habitats can provide a useful estimate of the magnitude of effective dispersal. Here we study the influence of spatial and local processes on colonization rates into new ponds that indicate differential dispersal limitation of major zooplankton taxa, with important implications for metacommunity dynamics. We identify regional and local factors that affect zooplankton colonization rates and spatial patterns in a large-scale experimental system. Our study differs from others in the unique setup of the experimental pond area by which we were able to test spatial and environmental variables at a large spatial scale. We quantified colonization rates separately for the Copepoda, Cladocera and Rotifera from samples collected over a period of 21 months in 48 newly constructed temporary ponds of 0.18-2.95 ha distributed in a restored wetland area of 2,700 ha in Doñana National Park, Southern Spain. Species richness upon initial sampling of new ponds was about one third of that in reference ponds, although the rate of detection of new species from thereon were not significantly different, probably owing to high turnover in the dynamic, temporary reference ponds. Environmental heterogeneity had no detectable effect on colonization rates in new ponds. In contrast, connectivity, space (based on latitude and longitude) and surface area were key determinants of colonization rates for copepods and cladocerans. This suggests dispersal limitation in cladocerans and copepods, but not in rotifers, possibly due to differences in propagule size and abundance.

Effects of the fungicide metiram in outdoor freshwater microcosms: responses of invertebrates, primary producers and microbes.

PubMed

Lin, Ronghua; Buijse, Laura; Dimitrov, Mauricio R; Dohmen, Peter; Kosol, Sujitra; Maltby, Lorraine; Roessink, Ivo; Sinkeldam, Jos A; Smidt, Hauke; Van Wijngaarden, René P A; Brock, Theo C M

2012-07-01

The ecological impact of the dithiocarbamate fungicide metiram was studied in outdoor freshwater microcosms, consisting of 14 enclosures placed in an experimental ditch. The microcosms were treated three times (interval 7 days) with the formulated product BAS 222 28F (Polyram®). Intended metiram concentrations in the overlying water were 0, 4, 12, 36, 108 and 324 μg a.i./L. Responses of zooplankton, macroinvertebrates, phytoplankton, macrophytes, microbes and community metabolism endpoints were investigated. Dissipation half-life (DT₅₀) of metiram was approximately 1-6 h in the water column of the microcosm test system and the metabolites formed were not persistent. Multivariate analysis indicated treatment-related effects on the zooplankton (NOEC(community) = 36 μg a.i./L). Consistent treatment-related effects on the phytoplankton and macroinvertebrate communities and on the sediment microbial community could not be demonstrated or were minor. There was no evidence that metiram affected the biomass, abundance or functioning of aquatic hyphomycetes on decomposing alder leaves. The most sensitive populations in the microcosms comprised representatives of Rotifera with a NOEC of 12 μg a.i./L on isolated sampling days and a NOEC of 36 μg a.i./L on consecutive samplings. At the highest treatment-level populations of Copepoda (zooplankton) and the blue-green alga Anabaena (phytoplankton) also showed a short-term decline on consecutive sampling days (NOEC = 108 μg a.i./L). Indirect effects in the form of short-term increases in the abundance of a few macroinvertebrate and several phytoplankton taxa were also observed. The overall community and population level no-observed-effect concentration (NOEC(microcosm)) was 12-36 μg a.i./L. At higher treatment levels, including the test systems that received the highest dose, ecological recovery of affected measurement endpoints was fast (effect period < 8 weeks).

Cryptic or pseudocryptic: can morphological methods inform copepod taxonomy? An analysis of publications and a case study of the Eurytemora affinis species complex

PubMed Central

Lajus, Dmitry; Sukhikh, Natalia; Alekseev, Victor

2015-01-01

Interest in cryptic species has increased significantly with current progress in genetic methods. The large number of cryptic species suggests that the resolution of traditional morphological techniques may be insufficient for taxonomical research. However, some species now considered to be cryptic may, in fact, be designated pseudocryptic after close morphological examination. Thus the “cryptic or pseudocryptic” dilemma speaks to the resolution of morphological analysis and its utility for identifying species. We address this dilemma first by systematically reviewing data published from 1980 to 2013 on cryptic species of Copepoda and then by performing an in-depth morphological study of the former Eurytemora affinis complex of cryptic species. Analyzing the published data showed that, in 5 of 24 revisions eligible for systematic review, cryptic species assignment was based solely on the genetic variation of forms without detailed morphological analysis to confirm the assignment. Therefore, some newly described cryptic species might be designated pseudocryptic under more detailed morphological analysis as happened with Eurytemora affinis complex. Recent genetic analyses of the complex found high levels of heterogeneity without morphological differences; it is argued to be cryptic. However, next detailed morphological analyses allowed to describe a number of valid species. Our study, using deep statistical analyses usually not applied for new species describing, of this species complex confirmed considerable differences between former cryptic species. In particular, fluctuating asymmetry (FA), the random variation of left and right structures, was significantly different between forms and provided independent information about their status. Our work showed that multivariate statistical approaches, such as principal component analysis, can be powerful techniques for the morphological discrimination of cryptic taxons. Despite increasing cryptic species

Distinctive mitochondrial genome of Calanoid copepod Calanus sinicus with multiple large non-coding regions and reshuffled gene order: Useful molecular markers for phylogenetic and population studies

PubMed Central

2011-01-01

Background Copepods are highly diverse and abundant, resulting in extensive ecological radiation in marine ecosystems. Calanus sinicus dominates continental shelf waters in the northwest Pacific Ocean and plays an important role in the local ecosystem by linking primary production to higher trophic levels. A lack of effective molecular markers has hindered phylogenetic and population genetic studies concerning copepods. As they are genome-level informative, mitochondrial DNA sequences can be used as markers for population genetic studies and phylogenetic studies. Results The mitochondrial genome of C. sinicus is distinct from other arthropods owing to the concurrence of multiple non-coding regions and a reshuffled gene arrangement. Further particularities in the mitogenome of C. sinicus include low A + T-content, symmetrical nucleotide composition between strands, abbreviated stop codons for several PCGs and extended lengths of the genes atp6 and atp8 relative to other copepods. The monophyletic Copepoda should be placed within the Vericrustacea. The close affinity between Cyclopoida and Poecilostomatoida suggests reassigning the latter as subordinate to the former. Monophyly of Maxillopoda is rejected. Within the alignment of 11 C. sinicus mitogenomes, there are 397 variable sites harbouring three 'hotspot' variable sites and three microsatellite loci. Conclusion The occurrence of the circular subgenomic fragment during laboratory assays suggests that special caution should be taken when sequencing mitogenomes using long PCR. Such a phenomenon may provide additional evidence of mitochondrial DNA recombination, which appears to have been a prerequisite for shaping the present mitochondrial profile of C. sinicus during its evolution. The lack of synapomorphic gene arrangements among copepods has cast doubt on the utility of gene order as a useful molecular marker for deep phylogenetic analysis. However, mitochondrial genomic sequences have been valuable markers for

Egg number-egg size: an important trade-off in parasite life history strategies.

PubMed

Cavaleiro, Francisca I; Santos, Maria J

2014-03-01

Parasites produce from just a few to many eggs of variable size, but our understanding of the factors driving variation in these two life history traits at the intraspecific level is still very fragmentary. This study evaluates the importance of performing multilevel analyses on egg number and egg size, while characterising parasite life history strategies. A total of 120 ovigerous females of Octopicola superba (Copepoda: Octopicolidae) (one sample (n=30) per season) were characterised with respect to different body dimensions (total length; genital somite length) and measures of reproductive effort (fecundity; mean egg diameter; total reproductive effort; mean egg sac length). While endoparasites are suggested to follow both an r- and K-strategy simultaneously, the evidence found in this and other studies suggests that environmental conditions force ectoparasites into one of the two alternatives. The positive and negative skewness of the distributions of fecundity and mean egg diameter, respectively, suggest that O. superba is mainly a K-strategist (i.e. produces a relatively small number of large, well provisioned eggs). Significant sample differences were recorded concomitantly for all body dimensions and measures of reproductive effort, while a general linear model detected a significant influence of season*parasite total length in both egg number and size. This evidence suggests adaptive phenotypic plasticity in body dimensions and size-mediated changes in egg production. Seasonal changes in partitioning of resources between egg number and size resulted in significant differences in egg sac length but not in total reproductive effort. Evidence for a trade-off between egg number and size was found while controlling for a potential confounding effect of parasite total length. However, this trade-off became apparent only at high fecundity levels, suggesting a state of physiological exhaustion. Copyright © 2014 Australian Society for Parasitology Inc. Published

A comparative study on mesozooplankton abundance and diversity between a protected and an unprotected coastal area of Andaman Islands.

PubMed

Pillai, Honey U K; Jayalakshmy, K V; Biju, A; Jayalakshmi, K J; Paulinose, V T; Devi, C B L; Nair, V R; Revichandran, C; Menon, N R; Achuthankutty, C T; Panampunnayil, S U

2014-06-01

The study was carried out to understand the variability in phytoplankton production (Chlorophyll a) and mesozooplankton diversity from two different shallow coastal regions of south Andaman viz. Port Blair Bay (PBB), the only real urban area among the islands and Mahatma Gandhi Marine National Park, a Marine Protected Area (MPA) at Wandoor. Seasonal sampling was carried out during the Northeast monsoon (NEM--November 2005), Intermonsoon (IM--April 2006), and Southwest monsoon (SWM--August 2006). Significant (P < 0.05) seasonal variation was observed in the environmental variables at both the regions. Higher average chlorophyll a (Chl. a) and mesozooplankton standing stock were observed at PBB compared to MPA, but the seasonal variation observed was marginal at both the study areas. Chl. a showed a steep increasing gradient from outer to the inner regions of the PBB. The number of zooplankton taxa recorded at both areas was quite similar, but marked differences were noticed in their relative contribution to the total abundance. Eventhough the Copepoda dominated at both the areas, the non-copepod taxa differed significantly between the regions. Dominance of carnivores such as siphonophores and chaetognaths were noticed at PBB, while filter feeders such as appendicularians and decapod larvae were more abundant at MPA. A total of 20 and 21 copepod families was recorded from PBB and MPA, respectively. Eleven species of chaetognaths were observed as common at both areas. Larval decapods were found to be predominant at MPA with 20 families; whereas, at PBB, only 12 families were recorded. In the light of the recent reports on various changes occurring in the coastal waters of the Andaman Islands, it is suspected that the difference in Chl. a as well as the mesozooplankton standing stock and community structure observed between the two study areas may be related to the various anthropogenic events influencing the coastal waters.

The deep-sea zooplankton of the North, Central, and South Atlantic: Biomass, abundance, diversity

NASA Astrophysics Data System (ADS)

Vereshchaka, Alexander; Abyzova, Galina; Lunina, Anastasia; Musaeva, Eteri

2017-03-01

Ocean-scale surveys of vertical distribution of the zooplankton from the surface to the bathypelagic zone along transects are quite rare in the North Atlantic and absent in the Equatorial and South Atlantic. We present the first deep-sea quantitative survey of the zooplankton in the Equatorial and South Atlantic, analyze the interaction between environment (depth, water masses, surface productivity) and zooplankton abundance and biomass, and assess the biodiversity and role of copepods in various deep strata. Samples were taken at 20 sites along a submeridional transect between 40°N and 30°S at four discrete depth strata: epi- meso-, upper- and lower- bathypelagic. A closing Bogorov-Rass plankton net (1 m2 opening, 500 μm mesh size, towed at a speed of 1 m s-1) was used and three major plankton groups were defined: non-gelatinous mesozooplankton (mainly copepods and chaetognaths; 1-30 mm length), gelatinous mesozooplankton (mainly siphonophorans, medudae and salps; individual or zooid; 1-30 mm length) and macroplankton (mainly shrimps; over 30 mm length). Over 300 plankton taxa were identified, among which 243 belonged to Copepoda. Two-dimensional distribution (latitude versus depth zone) of major group biomass, total copepod abundance, and abundance of dominant species is presented as well as distribution of biodiversity parameters (number of species, Shannon and 'dominance' indices). Biomass and abundance of all major groups were depth-dependent. The number of taxa (N) was depended on surface productivity, diversity of the communities was strongly linked to depth, whilst 'evenness' was independant upon both variables. Each of depth strata was inhabited by distinct copepod assemblages, which significantly differed from each other. The paper is concluded with brief descriptions of the deep Atlantic plankton communities from studied strata.

Ecological impacts of time-variable exposure regimes to the fungicide azoxystrobin on freshwater communities in outdoor microcosms.

PubMed

Zafar, Mazhar Iqbal; Belgers, J Dick M; Van Wijngaarden, Rene P A; Matser, Arriënne; Van den Brink, Paul J

2012-05-01

This paper evaluates the effects of different time-varying exposure patterns of the strobilurin fungicide azoxystrobin on freshwater microsocosm communities. These exposure patterns included two treatments with a similar peak but different time-weighted average (TWA) concentrations, and two treatments with similar TWA but different peak concentrations. The experiment was carried out in outdoor microcosms under four different exposure regimes; (1) a continuous application treatment of 10 μg/L (CAT(10)) for 42 days (2), a continuous application treatment of 33 μg/L (CAT(33)) for 42 days (3), a single application treatment of 33 μg/L (SAT(33)) and (4) a four application treatment of 16 μg/L (FAT(16)), with a time interval of 10 days. Mean measured 42-d TWA concentrations in the different treatments were 9.4 μg/L (CAT(10)), 32.8 μg/L (CAT(33)), 14.9 μg/L (SAT(33)) and 14.7 μg/L (FAT(16)). Multivariate analyses demonstrated significant changes in zooplankton community structure in all but the CAT(10) treated microcosms relative to that of controls. The largest adverse effects were reported for zooplankton taxa belonging to Copepoda and Cladocera. By the end of the experimental period (day 42 after treatment), community effects were of similar magnitude for the pulsed treatment regimes, although the magnitude of the initial effect was larger in the SAT(33) treatment. This indicates that for long-term effects the TWA is more important for most zooplankton species in the test system than the peak concentration. Azoxystrobin only slightly affected some species of the macroinvertebrate, phytoplankton and macrophyte assemblages. The overall no observed ecologically adverse effect concentrations (NOEAEC) in this study was 10 µg/L.

A new anchialine Stephos Scott from the Yucatan Peninsula with notes on the biogeography and diversity of the genus (Copepoda, Calanoida, Stephidae)

PubMed Central

Suárez-Morales, Eduardo; Gutiérrez-Aguirre, Martha A.; Cervantes-Martínez, Adrián; Iliffe, Thomas M.

2017-01-01

Abstract Surveys of the anchialine crustacean fauna of the Yucatan Peninsula (YP), Mexico, have revealed the occurrence of calanoid copepods. The genus Stephos Scott, 1892, belonging to the family Stephidae is among the most frequent and widely distributed groups in anchialine caves but has not been hitherto recorded from the YP. Recent collections from an anchialine cave in an island off the northern coast of the YP yielded many specimens of a new species of Stephos. The new taxon, S. fernandoi sp. n., is described here based on male and female specimens. The new species is clearly distinguished from its congeners by the following characters: male left fifth leg with three terminal lamellae plus subdistal process, right leg with distal row of peg-like elements; female fifth leg with single long, acute apical process; genital double-somite with two rows each of 4 long spinules adjacent to operculum; legs 2-4 with articulated setae. The diversity of the genus shows regional differences; the Australia-Western Pacific region is the most diverse (eleven species), followed by the Mediterranean (seven species) and the Northeastern Atlantic (six species); only four species are known from the Northwestern Tropical Atlantic (NWTA). The morphology of the female fifth leg was examined to explore possible biogeographic trends in the genus; patterns suggest multiple colonization events in the highly diverse regions and a relatively recent radiation in the NWTA, characterized by anchialine forms. The introduction of stephid copepods in the region may be a relatively recent event derived from colonization of benthopelagic ancestral forms and subsequent invasion onto cave habitats. The new species appears to be linked to the strictly anchialine Miostephos. PMID:28769658

A new anchialine Stephos Scott from the Yucatan Peninsula with notes on the biogeography and diversity of the genus (Copepoda, Calanoida, Stephidae).

PubMed

Suárez-Morales, Eduardo; Gutiérrez-Aguirre, Martha A; Cervantes-Martínez, Adrián; Iliffe, Thomas M

2017-01-01

Surveys of the anchialine crustacean fauna of the Yucatan Peninsula (YP), Mexico, have revealed the occurrence of calanoid copepods. The genus Stephos Scott, 1892, belonging to the family Stephidae is among the most frequent and widely distributed groups in anchialine caves but has not been hitherto recorded from the YP. Recent collections from an anchialine cave in an island off the northern coast of the YP yielded many specimens of a new species of Stephos . The new taxon, S. fernandoi sp. n. , is described here based on male and female specimens. The new species is clearly distinguished from its congeners by the following characters: male left fifth leg with three terminal lamellae plus subdistal process, right leg with distal row of peg-like elements; female fifth leg with single long, acute apical process; genital double-somite with two rows each of 4 long spinules adjacent to operculum; legs 2-4 with articulated setae. The diversity of the genus shows regional differences; the Australia-Western Pacific region is the most diverse (eleven species), followed by the Mediterranean (seven species) and the Northeastern Atlantic (six species); only four species are known from the Northwestern Tropical Atlantic (NWTA). The morphology of the female fifth leg was examined to explore possible biogeographic trends in the genus; patterns suggest multiple colonization events in the highly diverse regions and a relatively recent radiation in the NWTA, characterized by anchialine forms. The introduction of stephid copepods in the region may be a relatively recent event derived from colonization of benthopelagic ancestral forms and subsequent invasion onto cave habitats. The new species appears to be linked to the strictly anchialine Miostephos .

Transcriptome survey of the lipid metabolic pathways involved in energy production and ecdysteroid synthesis in the salmon louse Caligus rogercresseyi (Crustacea: Copepoda).

PubMed

Gonçalves, Ana Teresa; Farlora, Rodolfo; Gallardo-Escárate, Cristian

2014-10-01

The goal of this study was to identify and analyze the lipid metabolic pathways involved in energy production and ecdysteroid synthesis in the ectoparasite copepod Caligus rogercresseyi. Massive transcriptome sequencing analysis was performed during the infectious copepodid larval stage, during the attached chalimus larval stage, and also in female and male adults. Thirty genes were selected for describing the pathways, and these were annotated for proteins or enzymes involved in lipid digestion, absorption, and transport; fatty acid degradation; the synthesis and degradation of ketone bodies; and steroid and ecdysteroid syntheses. Differential expression of these genes was analyzed by ontogenic stage and discussed considering each stage's feeding habits and energetic needs. Copepodids showed a low expression of fatty acid digestion genes, reflected by a non-feeding behavior, and the upregulation of genes involved in steroid biosynthesis, which was consistent with a pathway for cholesterol synthesis during ecdysis. The chalimus stage showed an upregulation of genes related to fatty acid digestion, absorption, and transport, as well as to fatty acid degradation and the synthesis of ketone bodies, therefore suggesting that lipids ingested from the mucus and skin of the host fish are metabolized as important sources of energy. Adult females also showed a pattern of high lipid metabolism for energy supply and mobilization in relation to reproduction and vitellogenesis. Adult females and males revealed different lipid metabolism patterns that reflected different energetic needs. This study reports for the first time the probable lipid metabolic pathways involved in the energy production and ecdysteroid synthesis of C. rogercresseyi. Copyright © 2014 Elsevier Inc. All rights reserved.

Infestation of Lernaeenicus seeri (Copepoda: Pennellidae) and Hirudinella ventricosa (Digenea: Hirudinellidae) on wahoo Acanthocybium solandri collected from Parangipettai, southeast coast of India.

PubMed

Raja, K; Venmathi Maran, B A; Gopalakrishnan, A; Saravanakumar, A; Vijayakumar, R; Sinduja, K

2014-09-01

A commercially important fish, wahoo Acanthocybium solandri (Cuvier, 1832) (Scombridae), was collected to study the infestation of parasites from Parangipettai landing center, Tamil Nadu, southeast coast of India for a period of one year from January to December 2011. A total of 644 fish were captured and screened for parasites. Off 644 fish, 270 were infested by a parasitic copepod Lernaeenicus seeri Kirtisinghe, 1934 (Siphonostomatoida: Pennellidae) on the body surface. It is a mesoparasite, since the head and neck are inserted and attached to the muscle by making a wound/hole on the body and the rest of the parasite body with the egg sacs hanging outside. Prevalence was recorded as 42.29% with mean and maximum intensity at 3.22 and 33, respectively. Seasonal study showed that the prevalence was highest (62.82 %) during postmonsoon. Simultaneously, some of the fish (n = 144) were internally observed for the presence of parasites and we found that 101 fish were infested with an endoparasite digenean Hirudinella ventricosa (Pallas, 1774) (Hirudinellidae) in the stomach. Prevalence was recorded as 70.9%, and mean intensity of 1.62 and maximum intensity of 3 were also noted. The overall percentage of both copepod and digenean infestation were recorded as 60.42%. The infestation was high in postmonsoon season for both parasites. This is the first record of L. seeri from Indian waters and the second record of occurrence worldwide. Significant interactions were observed between season and infestation of both parasites (P<0.05).

A new species of the rare endoparasitic copepod Entobius (Copepoda: Entobiidae) from Mexico with a key to the species of the genus.

PubMed

Suárez-Morales, Eduardo; Carrera-Parra, Luis F

2012-09-01

Abstract: In a study of the benthic polychaete fauna of the southern Gulf of Mexico and the Caribbean Sea, several specimens of the terebellid polychaete Scionides reticulata (Ehlers) were found to host endoparasitic copepods that represent an undescribed species of the rare cyclopoid genus Entobius Dogiel, 1948. The new species, E. scionides sp. n., can be distinguished from its congeners by a combination of characters including a genital region without constrictions, three-segmented antennules, a reduced antenna with a blunt terminal process, reduced ornamentation of endopods of legs 1-4 and its relatively small size (2.3-2.7 mm). It is the smallest species of the genus. Comments on immature females are also provided, but males of this species remain unknown. It has a high prevalence (53%) in populations of the terebellid S. reticulata in the southern Gulf of Mexico, but it is absent from the Caribbean. This is the first occurrence of this copepod genus in the Americas. The finding of the new species of Entobius in S. reticulata confirms the strict specificity of most members of the genus and expands the host range of this copepod genus. A key for the identification of the species of Entobius is provided.

Colobomatus kimi sp. nov. (Copepoda: Philichthyidae) parasitic in the dwarf goatfish Upeneus parvus Poey, 1852 (Perciformes: Mullidae) in the South Atlantic Ocean.

PubMed

Paschoal, Fabiano; Pereira, Aldenice N; Luque, José Luis

2016-10-11

A new species of copepod, Colobomatus kimi sp. nov., belonging to the cyclopoid family Philichthyidae Vogt, 1877, is proposed based on female specimens collected from the pores of the cephalic sensory system of the dwarf goatfish, Upeneus parvus Poey from the southeastern Brazilian coastal zone. The new species can be distinguished from its closest congeners by the unique combination of characters displayed by the female, including the forked caudal rami, the position of the midventral cephalic process shorter in relation to the lateral cephalic processes, and the presence of paired genital processes. The new species is the first member of Colobomatus Hesse, 1873 found to parasitize mullids of the genus Upeneus.

A new species of Monstrilla Dana, 1849 (Copepoda: Monstrilloida: Monstrillidae) from Korea, including a key to species from the north-west Pacific.

PubMed

Lee, Jimin; Chang, Cheon Young

2016-10-11

A new species of monstrilloid copepod belonging to the genus Monstrilla Dana, 1849 is recorded from South Korea. Specimens were obtained between May of 2012 and January of 2014 from inshore waters along the coasts of the East Sea, South Sea, and Jeju Island, using a light trap installed at quays and wharves overnight. Monstrilla ilhoii sp. nov. is characterized by a remarkable combination of a large body size (females about 3.8 mm long, males about 2.8 mm long), a polygonal ridge pattern (cuticular reticulation) over the entire body surface, and an antennule armature featuring a supernumerary spiniform seta (4d₃) in females and a dagger-shaped distal spine (6₂) in both sexes. In other respects M. ilhoii sp. nov. most closely resembles M. lata Desai & Bal, 1963; both species have one and three setae on the endopodal and exopodal lobes, respectively, of female leg 5, a horseshoe-shaped male genital apparatus with marked undulations along the whole distal margin, and six setae on each caudal ramus in both sexes. This paper provides a description of the new species, taxonomic remarks on its morphological features, and differential diagnoses with respect to its allies. Scanning electron microscopy was used to document significant morphological microcharacters. The species of Monstrilla known from five sub-regions of the north-west Pacific are enumerated with the source references, and keys to the females and males of these species are provided.

Response of abyssal Copepoda Harpacticoida (Crustacea) and other meiobenthos to an artificial disturbance and its bearing on future mining for polymetallic nodules

NASA Astrophysics Data System (ADS)

Ahnert, Ahmed; Schriever, Gerd

Long-term effects of an anthropogenic physical disturbance on the Harpacticoida taxocene at a deep-sea site were investigated during the course of the disturbance and recolonization (DISCOL) experiment in a manganese nodule area in the southeastern Pacific. Nineteen harpacticoid copepod families were found, contributing 9-12% to the metazoan meiofauna of the experimental area (Nematoda 72-80%). Twelve families occurred in sufficient numbers to be considered representatively sampled. Dominant are the Ameiridae (17%) followed by Ectinosomatidae, Argestidae, Tisbidae, Neobradyidae, Diosaccidae, Paranannopidae, Paramesochridae, Canthocamptidae, Cletodidae, Thalestridae and Huntemanniidae. These families are mainly distributed at random. Basic data on developmental stage composition and sex ratio of total Harpacticoida as well as vertical distribution of harpacticoid families in the sediment column are provided. Within the overall aim of the experiment, which was to assess the ecological risks of future deep-sea manganese nodule mining, we conducted multivariate community analyses based on the familial composition of the Harpacticoida assemblages immediately before and after experimental impact as well as seven years later. We were not able to detect a community response at the family level immediately after impact. An identification of the Tisbidae to species, however, revealed initial disturbance effects. After seven years we found significant differences in the assemblage composition of the directly disturbed portions of the experimental area and the secondarily disturbed areas in between, which to some extent had received blanketing from sediment plumes created during the experimental disturbance. Best discriminating families for long-term effects are the Ameiridae, Argestidae and Thalestridae. Their potential value as indicator taxa for monitoring disturbances in the deep sea is discussed, including some considerations on a cost-effective design of such monitoring programs that would include the meiofaunal Harpacticoida.

Two new stygobiotic species of Elaphoidella (Crustacea: Copepoda: Harpacticoida) with comments on geographical distribution and ecology of harpacticoids from caves in Thailand.

PubMed

Watiroyram, Santi; Brancelj, Anton; Sanoamuang, La-Orsri

2015-02-16

Elaphoidella thailandensis sp. nov. and E. jaesornensis sp. nov., collected during an investigation of cave-dwelling copepod fauna in the northern part of Thailand, are described and figured herein. The new species were collected from pools filled by percolating water from the unsaturated zone of a karstic aquifer in Phitsanulok and Lampang Provinces, respectively. Elaphoidella thailandensis, from Tham Khun cave, is distinguished from its congeners by the two-segmented endopod of pediger 1, the absence of endopod on pediger 4, and the setal formula 4, 5, 6 for the distal exopodal segment of pedigers 2-4. Elaphoidella jaesornensis, from Tham Phar Ngam cave, is distinguished from its most closely related species, E. namnaoensis Brancelj, Watiroyram & Sanoamuang, 2010, by the armature formula of the endopod of pedigers 2-5. The geographical distribution and ecology of Harpacticoida from Thai caves is also presented.

A new genus of speleophriid copepod (Copepoda: Misophrioida) from a cenote in the Yucatan, Mexico with a phylogenetic analysis at the species level.

PubMed

Boxshall, Geoff A; Zylinski, Sarah; Jaume, Damià; Iliffe, Thomas M; Suárez-Morales, Eduardo

2014-06-23

A new genus and species of speleophriid copepod, Mexicophria cenoticola gen. et sp. nov., is described based on material collected from a cenote in the Yucatan Peninsula of Mexico. It is characterised by relatively reduced fifth legs that are located adjacent to the ventral midline in both sexes, by the possession of a bulbous swelling on the first antennulary segment in both sexes, and by the reduced setation of the swimming legs. The presence of just one inner margin seta on the second endopodal segment of legs 2 to 4 is a unique feature for the family. A phylogenetic analysis places the new genus on a basal lineage of the family together with its sister taxon, Boxshallia Huys, 1988, from Lanzarote in the Canary Islands, and recovers the existing genera as monophyletic units. The zoogeography is discussed at local, regional, ocean basin  and global scales.

Discovery of the male of the rare caligiform copepod Kabataia Kazachenko, Korotaeva & Kurochkin, 1972 (Copepoda: Siphonostomatoida), with a reconsideration of its phylogenetic affinities.

PubMed

Hutson, Kate S; Boxshall, Geoffrey A

2016-10-11

We report the discovery of the male of the rare caligiform copepod Kabataia ostorhynchi Kazachenko, Korotaeva & Kurochkin, 1972 on the gills of the type-host Oplegnathus woodwardi (Waite, 1900) captured in the Southern Ocean, off Australia. Light and scanning electron microscopy confirmed the unusual body plan of Kabataia Kazachenko, Korotaeva & Kurochkin, 1972, where only the first pedigerous somite is incorporated into the cephalothorax and the second and third pedigerous somites are fused to form a double-somite, visible both dorsally and ventrally. The adult female carries paired dorsal plates originating from the second pedigerous somite within this double-somite. In the male the second and third pedigerous somites are free and paired dorsal plates are present on the former. Kabataia exhibits sexual dimorphism in an unusually wide range of limbs. Most remarkable is the tubular extension from the exit pore of the maxillary gland at the base of the maxilla which reaches beyond the anterior margin of the mouth tube; this is present in the male only. Kabataia exhibits a functional articulation between the first and second pedigerous somites and thus lacks the diagnostic apomorphy of the family Trebiidae (incorporation of both first and second pedigerous somites into the cephalothorax). We propose to transfer Kabataia to the Pandaridae, since it shares the key synapomorphies of this family. Furthermore, we propose to transfer Innaprokofevnas Kazachenko, 2001 to the Dissonidae, which leaves Trebius Krøyer, 1838 as the only genus within the Trebiidae. The correct spelling of Philorthragoriscus Horst, 1897 is noted.

Descriptions of two new species of Rhizorhina Hansen, 1892 (Copepoda: Siphonostomatoida: Nicothoidae) parasitic on tanaidacean crustaceans, with a note on their phylogenetic position.

PubMed

Kakui, Keiichi

2016-01-01

Two new species of nicothoid copepod are described. Rhizorhina ohtsukai n. sp. found on a leptocheliid (Leptochelia sp.) collected at depths of 151-136 m in the North Pacific Ocean is most similar to Rhizorhina aesthetes Boxshall & Harrison, 1988 but can be distinguished by the possession of a narrower body with a rounded anterior end, and in the position of the gonopores. Rhizorhina soyoae n. sp. found on an apseudid (Fageapseudes sp.) collected at depths of 1,595-1,557 m in East China Sea most closely resembles Rhizorhina tanaidaceae Gotto, 1984 but differs in having a narrower body with a rounded anterior end. Partial nucleotide sequences of the cytochrome c oxidase subunit I (COI) gene were obtained from the two copepods in order to enable future barcoding. A phylogenetic reconstruction based on the 18S rRNA gene placed the copepods within the Siphonostomatoida Burmeister, 1835, with the nicothoid Choniosphaera maenadis (Bloch & Gallien, 1933), and separate from the Rhizorhina spp. clade, suggesting that the family Nicothoidae Dana, 1849 is not monophyletic. This is the third report of copepods parasitic on tanaidacean crustaceans.

First record and redescription of Macandrewella cochinensis Gopalakrishnan, 1973 (Copepoda, Scolecitrichidae) from the Red Sea, with notes on swarm formation

PubMed Central

El-Sherbiny, Mohsen M.; Al-Aidaroos, Ali M.

2013-01-01

Abstract During a study of the epipelagic zooplankton carried out near the fringing reef around Sharm El-Sheikh area, in the northern Red Sea, female and male specimens of the poorly known calanoid copepod Macandrewella cochinensis Gopalakrishnan, 1973 were collected. This is the first record of species occurrence in the Red Sea. Macandrewella cochinensis was previously known only from the offshore water of Cochin, south west of India. The Red Sea specimens are described in details herein to allow their comparison with the specimens from the type locality, because original description of M. cochinensis is incomplete and causes some taxonomic confusion. The most important characters that may have been overlooked in the original description are: shape of projections of the female distolateral prosomal borders, details of morphology of the asymmetrical female genital double-somite and presence of leg 5 in female. PMID:24194657

First record and redescription of Macandrewella cochinensis Gopalakrishnan, 1973 (Copepoda, Scolecitrichidae) from the Red Sea, with notes on swarm formation.

PubMed

El-Sherbiny, Mohsen M; Al-Aidaroos, Ali M

2013-01-01

During a study of the epipelagic zooplankton carried out near the fringing reef around Sharm El-Sheikh area, in the northern Red Sea, female and male specimens of the poorly known calanoid copepod Macandrewella cochinensis Gopalakrishnan, 1973 were collected. This is the first record of species occurrence in the Red Sea. Macandrewella cochinensis was previously known only from the offshore water of Cochin, south west of India. The Red Sea specimens are described in details herein to allow their comparison with the specimens from the type locality, because original description of M. cochinensis is incomplete and causes some taxonomic confusion. The most important characters that may have been overlooked in the original description are: shape of projections of the female distolateral prosomal borders, details of morphology of the asymmetrical female genital double-somite and presence of leg 5 in female.

Fish farms, parasites, and predators: implications for salmon population dynamics.

PubMed

Krkosek, Martin; Connors, Brendan M; Ford, Helen; Peacock, Stephanie; Mages, Paul; Ford, Jennifer S; Morton, Alexandra; Volpe, John P; Hilborn, Ray; Dill, Lawrence M; Lewis, Mark A

2011-04-01

For some salmon populations, the individual and population effects of sea lice (Lepeophtheirus salmonis) transmission from sea cage salmon farms is probably mediated by predation, which is a primary natural source of mortality of juvenile salmon. We examined how sea lice infestation affects predation risk and mortality of juvenile pink (Oncorhynchus gorbuscha) and chum (O. keta) salmon, and developed a mathematical model to assess the implications for population dynamics and conservation. A risk-taking experiment indicated that infected juvenile pink salmon accept a higher predation risk in order to obtain foraging opportunities. In a schooling experiment with juvenile chum salmon, infected individuals had increased nearest-neighbor distances and occupied peripheral positions in the school. Prey selection experiments with cutthroat trout (O. clarkii) predators indicated that infection reduces the ability of juvenile pink salmon to evade a predatory strike. Group predation experiments with coho salmon (O. kisutch) feeding on juvenile pink or chum salmon indicated that predators selectively consume infected prey. The experimental results indicate that lice may increase the rate of prey capture but not the handling time of a predator. Based on this result, we developed a mathematical model of sea lice and salmon population dynamics in which parasitism affects the attack rate in a type II functional response. Analysis of the model indicates that: (1) the estimated mortality of wild juvenile salmon due to sea lice infestation is probably higher than previously thought; (2) predation can cause a simultaneous decline in sea louse abundance on wild fish and salmon productivity that could mislead managers and regulators; and (3) compensatory mortality occurs in the saturation region of the type II functional response where prey are abundant because predators increase mortality of parasites but not overall predation rates. These findings indicate that predation is an

Immunization against parasitic diseases of fish.

PubMed

Woo, P T

1997-01-01

sonicated/killed cercariae or metacercariae have fewer metacercariae in the eyes and survives longer. Lepeophtheirus salmonis and Caligus elongatus are parasitic copepods (sea lice), and they are important parasites of Atlantic salmon in cage cultures. A vaccine against fish lice is plausible, and the efficacy of about 20 candidate antigens in protecting fish is being tested.

A new species of Echinolaophonte and record of E. armiger (Gurney, 1927) (Crustacea, Copepoda, Harpacticoida, Laophontidae) from the Caribbean with a key to species

PubMed Central

Fuentes-Reinés, Juan Manuel; Suárez-Morales, Eduardo

2017-01-01

Abstract A new species of the harpacticoid copepod genus Echinolaophonte is described here from specimens obtained during a biological survey of Rodadero Bay, a coastal system in the Colombian Caribbean. This species has been previously recorded as E. armiger Gurney, 1927 in different geographic areas (Indian and Pacific Oceans). The Colombian specimens recognized as E. villabonae sp. n. and true E. armiger are deemed as distinct species based on differences in several features of which the shape of the rostrum and the dorsal spinous process on the prosome are among the most distinctive. These and other characters are shared by specimens recorded as E. armiger from Caroline Islands and Australia that are now incorporated to the new species. The finding of the true E. armiger, previously known only from Egypt, the Texan coast, Brazil, and possibly Bermuda, constitutes the first record of this species in the western Caribbean and a regional range extension. A key to the identification of the 13 known species of the genus is also provided. PMID:29308028

A new species of Echinolaophonte and record of E. armiger (Gurney, 1927) (Crustacea, Copepoda, Harpacticoida, Laophontidae) from the Caribbean with a key to species.

PubMed

Fuentes-Reinés, Juan Manuel; Suárez-Morales, Eduardo

2017-01-01

A new species of the harpacticoid copepod genus Echinolaophonte is described here from specimens obtained during a biological survey of Rodadero Bay, a coastal system in the Colombian Caribbean. This species has been previously recorded as E. armiger Gurney, 1927 in different geographic areas (Indian and Pacific Oceans). The Colombian specimens recognized as E. villabonae sp. n. and true E. armiger are deemed as distinct species based on differences in several features of which the shape of the rostrum and the dorsal spinous process on the prosome are among the most distinctive. These and other characters are shared by specimens recorded as E. armiger from Caroline Islands and Australia that are now incorporated to the new species. The finding of the true E. armiger , previously known only from Egypt, the Texan coast, Brazil, and possibly Bermuda, constitutes the first record of this species in the western Caribbean and a regional range extension. A key to the identification of the 13 known species of the genus is also provided.

On Kiefer’s American Eucyclops (Copepoda, Eucyclopinae): redescriptions and comments on the historical records of E. delachauxi, E. prionophorus, E. bondi and E. leptacanthus

PubMed Central

Mercado-Salas, Nancy F.; Suárez-Morales, Eduardo

2014-01-01

Abstract The freshwater copepod genus Eucyclops contains many supposedly cosmopolitan species whose taxonomic status is still under discussion; some of them represent species complexes. The problem is not exclusive to these widespread species; there are several American Eucyclops needing a taxonomic re-evaluation. Based on the examination of Friedrich Kiefer’s collection in Karlsruhe, Germany, the type specimens of four American species of Eucyclops (E. delachauxi (Kiefer, 1926), E. prionophorus Kiefer, 1931, E. bondi Kiefer, 1934, E. leptacanthus Kiefer, 1956) were re-examined and redescribed using upgraded descriptive standards. Kiefer’s translated descriptions and unpublished original drawings of these species are also presented. Characters like the ornamentation of the antennal basis, ornamentation of intercoxal sclerites of the swimming legs 1–4, length of basipodal seta of leg 1, ornamentation of caudal rami, the presence of aesthetascs and modified setae on the antennules in male, and the structure of the male sixth leg are compared herein to aid a more accurate separation of these American species. A revision of the American records of these species confirms that some are likely to refer to undescribed species. Overall, the diversity of the American Eucyclops appears to be underestimated and certainly deserves further study. PMID:24843261

Preface: Recent Developments in Taxonomy and Biodiversity of Symbiotic Copepoda (Crustacea)-A Volume in Celebration of the Career of Prof. Il-Hoi Kim.

PubMed

Huys, Rony

2016-10-11

Symbiosis is one of the most successful modes of life displayed by aquatic organisms, as measured by the number of times it evolved and how many symbiotic species are presently in existence. Among the Crustacea copepods utilize an extraordinary range of hosts, occurring on virtually every phylum of marine macroinvertebrates and, jointly with the monogeneans, are the most speciose group of metazoan ectoparasites of marine fishes (Rhode 2005). Several species have a major impact on global finfish and shellfish aquaculture, causing significant effects on farm production, economic viability and sustainability (Shinn et al. 2015). Parasitism by copepods on other metazoans has evolved independently numerous times in the evolutionary history of animal life on Earth and has led to an exceptional diversity in morphologies, physiologies, life-strategies and habitat preferences of its members. Reflecting the diversity of hosts, copepods show an amazing variety of adaptations which secure infection of and survival on the hosts. Since the first descriptions of parasitic copepods occurring on fish by Linnaeus (1758) and the first report of a copepod utilizing an invertebrate host by Say (1818) (Clausidium caudatum (Say, 1818)) the number of described symbiotic copepods has seen a steady increase over a 200-yr period, culminating in a total of 5,306 valid species recognized today. About 38% of all described copepod species utilize either vertebrate (2,450 spp.) or invertebrate hosts (2,856 spp.), however, many host groups have not been thoroughly examined, and for this reason even approximate estimates of true species numbers are futile. Plotting the proposal of new species by decade (Fig. 1) shows a sharp rise since 1950 with 67% of the species having been described in the preceding 65 years. This period of exceptionally rapid progress can be attributed to a number of highly prolific investigators such as Arthur Humes, Il-Hoi Kim, Ju-shey Ho and Jan Stock who, single-handedly or in collaboration with other authors, described 698, 356, 290 and 246 species, respectively. Historically, the number of described copepod species parasitizing fish typically outnumbered those known to be associated with invertebrates. Only during the mid-1970s the species curves of both categories converged and during the last 30 years the discovery of new species associated with invertebrate hosts appears to progress more rapidly. Despite a significant drop in the number of specialists working on symbiotic copepods the steady addition of new taxa shows that the dynamism of their taxonomy is clearly set to continue.

Comparative evaluation of fecundity and survivorship of six copepod (Copepoda: Cyclopidae) species, in relation to selection of candidate biological control agents against Aedes aegypti.

PubMed

Phong, Tran Vu; Tuno, Nobuko; Kawada, Hitoshi; Takagi, Masahiro

2008-03-01

The fecundity and survival of 6 copepod species were assessed under laboratory conditions in order to choose the best candidates to control the aquatic stages of dengue mosquitoes in the field. Females of all the 6 species (Mesocyclops aspericornis, Mesocyclops pehpeiensis, Mesocyclops woutersi, Mesocyclops thermocyclopoides, Mesocyclops ogunnus, and Megacyclops viridis) mated more than once. Multiple mating resulted in increased egg production. The reproductive ability and longevity varied among the species, and M. aspericornis had the highest values. The lowest values were observed in M. thermocyclopoides. Multiple mating of males of M. aspericornis was also observed. The paternal fecundity decreased with each additional mating. There was no difference in the paternal fecundity between the males that mated at low and high female frequencies. The sperm stored in the M. aspericornis females remained viable for 30 days after storage under moist conditions at 25 degrees C or 15 degrees C. This feature in M. aspericornis represents an additional positive factor indicating that this species is a good biological agent for controlling mosquito larvae, especially in domestic water containers that may dry intermittently.

Impact of early salmon louse, Lepeophtheirus salmonis, infestation and differences in survival and marine growth of sea-ranched Atlantic salmon, Salmo salar L., smolts 1997–2009

PubMed Central

Skilbrei, O T; Finstad, B; Urdal, K; Bakke, G; Kroglund, F; Strand, R

2013-01-01

The impact of salmon lice on the survival of migrating Atlantic salmon smolts was studied by comparing the adult returns of sea-ranched smolts treated for sea lice using emamectin benzoate or substance EX with untreated control groups in the River Dale in western Norway. A total of 143 500 smolts were released in 35 release groups in freshwater from 1997 to 2009 and in the fjord system from 2007 to 2009. The adult recaptures declined gradually with release year and reached minimum levels in 2007. This development corresponded with poor marine growth and increased age at maturity of ranched salmon and in three monitored salmon populations and indicated unfavourable conditions in the Norwegian Sea. The recapture rate of treated smolts was significantly higher than the controls in three of the releases performed: the only release in 1997, one of three in 2002 and the only group released in sea water in 2007. The effect of treating the smolts against salmon lice was smaller than the variability in return rates between release groups, and much smaller that variability between release years, but its overall contribution was still significant (P < 0.05) and equivalent to an odds ratio of the probability of being recaptured of 1.17 in favour of the treated smolts. Control fish also tended to be smaller as grilse (P = 0.057), possibly due to a sublethal effect of salmon lice. PMID:23311746

A “Rosetta Stone” for metazoan zooplankton: DNA barcode analysis of species diversity of the Sargasso Sea (Northwest Atlantic Ocean)

NASA Astrophysics Data System (ADS)

Bucklin, Ann; Ortman, Brian D.; Jennings, Robert M.; Nigro, Lisa M.; Sweetman, Christopher J.; Copley, Nancy J.; Sutton, Tracey; Wiebe, Peter H.

2010-12-01

Species diversity of the metazoan holozooplankton assemblage of the Sargasso Sea, Northwest Atlantic Ocean, was examined through coordinated morphological taxonomic identification of species and DNA sequencing of a ˜650 base-pair region of mitochondrial cytochrome oxidase I (mtCOI) as a DNA barcode (i.e., short sequence for species recognition and discrimination). Zooplankton collections were made from the surface to 5,000 meters during April, 2006 on the R/V R.H. Brown. Samples were examined by a ship-board team of morphological taxonomists; DNA barcoding was carried out in both ship-board and land-based DNA sequencing laboratories. DNA barcodes were determined for a total of 297 individuals of 175 holozooplankton species in four phyla, including: Cnidaria (Hydromedusae, 4 species; Siphonophora, 47); Arthropoda (Amphipoda, 10; Copepoda, 34; Decapoda, 9; Euphausiacea, 10; Mysidacea, 1; Ostracoda, 27); and Mollusca (Cephalopoda, 8; Heteropoda, 6; Pteropoda, 15); and Chaetognatha (4). Thirty species of fish (Teleostei) were also barcoded. For all seven zooplankton groups for which sufficient data were available, Kimura-2-Parameter genetic distances were significantly lower between individuals of the same species (mean=0.0114; S.D. 0.0117) than between individuals of different species within the same group (mean=0.3166; S.D. 0.0378). This difference, known as the barcode gap, ensures that mtCOI sequences are reliable characters for species identification for the oceanic holozooplankton assemblage. In addition, DNA barcodes allow recognition of new or undescribed species, reveal cryptic species within known taxa, and inform phylogeographic and population genetic studies of geographic variation. The growing database of "gold standard" DNA barcodes serves as a Rosetta Stone for marine zooplankton, providing the key for decoding species diversity by linking species names, morphology, and DNA sequence variation. In light of the pivotal position of zooplankton in ocean

Modeling species richness and abundance of phytoplankton and zooplankton in radioactively contaminated water bodies.

PubMed

Shuryak, Igor

2018-06-05

Water bodies polluted by the Mayak nuclear plant in Russia provide valuable information on multi-generation effects of radioactive contamination on freshwater organisms. For example, lake Karachay was probably the most radioactive lake in the world: its water contained ∼2 × 10 7 Bq/L of radionuclides and estimated dose rates to plankton exceeded 5 Gy/h. We performed quantitative modeling of radiation effects on phytoplankton and zooplankton species richness and abundance in Mayak-contaminated water bodies. Due to collinearity between radioactive contamination, water body size and salinity, we combined these variables into one (called HabitatFactors). We employed a customized machine learning approach, where synthetic noise variables acted as benchmarks of predictor performance. HabitatFactors was the only predictor that outperformed noise variables and, therefore, we used it for parametric modeling of plankton responses. Best-fit model predictions suggested 50% species richness reduction at HabitatFactors values corresponding to dose rates of 10 4 -10 5  μGy/h for phytoplankton, and 10 3 -10 4  μGy/h for zooplankton. Under conditions similar to those in lake Karachay, best-fit models predicted 81-98% species richness reductions for various taxa (Cyanobacteria, Bacillariophyta, Chlorophyta, Rotifera, Cladocera and Copepoda), ∼20-300-fold abundance reduction for total zooplankton, but no abundance reduction for phytoplankton. Rotifera was the only taxon whose fractional abundance increased with contamination level, reaching 100% in lake Karachay, but Rotifera species richness declined with contamination level, as in other taxa. Under severe radioactive and chemical contamination, one species of Cyanobacteria (Geitlerinema amphibium) dominated phytoplankton, and rotifers from the genus Brachionus dominated zooplankton. The modeling approaches proposed here are applicable to other radioecological data sets. The results provide quantitative information

Interpopulation hybridization results in widespread viability selection across the genome in Tigriopus californicus

PubMed Central

2011-01-01

Background Genetic interactions within hybrids influence their overall fitness. Understanding the details of these interactions can improve our understanding of speciation. One experimental approach is to investigate deviations from Mendelian expectations (segregation distortion) in the inheritance of mapped genetic markers. In this study, we used the copepod Tigriopus californicus, a species which exhibits high genetic divergence between populations and a general pattern of reduced fitness in F2 interpopulation hybrids. Previous studies have implicated both nuclear-cytoplasmic and nuclear-nuclear interactions in causing this fitness reduction. We identified and mapped population-diagnostic single nucleotide polymorphisms (SNPs) and used these to examine segregation distortion across the genome within F2 hybrids. Results We generated a linkage map which included 45 newly elucidated SNPs and 8 population-diagnostic microsatellites used in previous studies. The map, the first available for the Copepoda, was estimated to cover 75% of the genome and included markers on all 12 T. californicus chromosomes. We observed little segregation distortion in newly hatched F2 hybrid larvae (fewer than 10% of markers at p < 0.05), but strikingly higher distortion in F2 hybrid adult males (45% of markers at p < 0.05). Hence, segregation distortion was primarily caused by selection against particular genetic combinations which acted between hatching and maturity. Distorted markers were not distributed randomly across the genome but clustered on particular chromosomes. In contrast to other studies in this species we found little evidence for cytonuclear coadaptation. Instead, different linkage groups exhibited markedly different patterns of distortion, which appear to have been influenced by nuclear-nuclear epistatic interactions and may also reflect genetic load carried within the parental lines. Conclusion Adult male F2 hybrids between two populations of T. californius exhibit

Exposure and effects of sediment-spiked fludioxonil on macroinvertebrates and zooplankton in outdoor aquatic microcosms.

PubMed

Yin, Xiao H; Brock, Theo C M; Barone, Lidia E; Belgers, J Dick M; Boerwinkel, Marie-Claire; Buijse, Laura; van Wijngaarden, René P A; Hamer, Mick; Roessink, Ivo

2018-01-01

Information from effects of pesticides in sediments at an ecosystem level, to validate current and proposed risk assessment procedures, is scarce. A sediment-spiked outdoor freshwater microcosm experiment was conducted with fludioxonil (lipophilic, non-systemic fungicide) to study exposure dynamics and treatment-related responses of benthic and pelagic macroinvertebrates and zooplankton. Besides blank control and solvent control systems the experiment had six different treatment levels (1.7-614mga.s./kg dry sediment) based around the reported 28-d No Observed Effect Concentration (NOEC) for Chironomus riparius (40mga.s./kg dry sediment). Twelve systems were available per treatment of which four were sacrificed on each of days 28, 56 and 84 after microcosm construction. Fludioxonil persisted in the sediment and mean measured concentrations were 53-82% of the initial concentration after 84days. The dissipation rate increased with the treatment level. Also exposure concentrations in overlying water were long-term, with highest concentrations 28days after initiation of the experiment. Sediment-dwelling Oligochaeta and pelagic Rotifera and Cladocera showed the most pronounced treatment-related declines. The most sensitive sediment-dwelling oligochaete was Dero digitata (population NOEC 14.2mga.s./kg dry sediment). The same NOEC was calculated for the sediment-dwelling macroinvertebrate community. The most sensitive zooplankton species was the cladoceran Diaphanosoma brachyurum (NOEC of 1.6μga.s./L in overlying water corresponding to 5.0mga.s./kg dry sediment). At the two highest treatments several rotifer taxa showed a pronounced decrease, while the zooplankton community-level NOEC was 5.6μga.s./L (corresponding to 14.2mga.s./kg dry sediment). Zooplankton taxa calanoid Copepoda and Daphnia gr. longispina showed a pronounced treatment-related increase (indirect effects). Consequently, an assessment factor of 10 to the chronic laboratory NOECs of Chironomus riparius

[Spatial and temporal variation in diet composition of invertivore fishes in a tropical stream, Venezuela].

PubMed

Ortaz, Mario; Martín, Ricardo; López-Ordaz, Adriana

2011-09-01

Invertivores fishes are an important component of neotropical streams and they represent a link between aquatic invertebrates and piscivorous species. This study evaluated the breadth diet and interspecific food overlap of nine invertivores fish species during three consecutive hydrological phases: falling (December/07, January/08, February/08 and March/08), low (April/08) and rising waters (June/08), in two sections of a Venezuelan neotropical stream, which were located at different elevation, high watershed (HW) and low watershed (LW). The fishes were collected with a beach seine (5mm mesh) between 8:00 and 11:00 hours. The diet of each species was evaluated using an index of relative importance (IRI), which includes as variables the number, weight and occurrence frequency of food items consumed. The Levin' index (B ) and Morisita (IM) were used to estimate the breadth diet and interspecific food overlap, respectively. All estimations were made using the numeric proportion of preys. Nine fish species were captured, eight Characiformes, of which three were captured in HW (Knodus deuteronoides, Creagrutus bolivari and C. melasma) and five in LW (Thoracocharax stellatus, Moenkhausia lepidura, Cheirodon pulcher, Ctenobrycon spilurus and Aphyocharax alburnus), and one Cyprinodontiformes (Poecilia reticulata), which was also found in HW. In HW aquatic insects were the main resource consumed by fishes while plant material and terrestrial arthropods were secondary resources. In LW the fishes ingested all of these items in addition to zooplankton (Copepoda, Cladocera and larval stages of Decapoda). However, there was a temporal replacement with a predominance of zooplankton in falling and low water. In general, the breadth diet decreased during the falling water in both sections and increased in rising water. However, the average breadth diet was higher in HW. The interspecific food overlap was high in HW while low values were more frequent in LW and its temporal

'Snorkel' lice barrier technology reduced two co- occurring parasites, the salmon louse (Lepeophtheirus salmonis) and the amoebic gill disease causing agent (Neoparamoeba perurans), in commercial salmon sea-cages.

PubMed

Wright, D W; Stien, L H; Dempster, T; Vågseth, T; Nola, V; Fosseidengen, J-E; Oppedal, F

2017-05-01

Diverse chemical-free parasite controls are gaining status in Atlantic salmon sea-cage farming. Yet, the intricacies of their use at commercial scale, including effects on co-occurring parasites, are seldom reported. A new salmon lice prevention method involves installing a deep net roof and 'snorkel' lice barrier in cages to shelter salmon from free-living infective larvae which concentrate at shallow depths, and allows salmon to jump and re- inflate their buoyancy-regulating swim bladder by swallowing air. We document use of snorkel cages (10m deep barrier) in commercial farms, where their effects on salmon lice levels, amoebic gill disease (AGD)-related gill scores, the cage environment, fish welfare and farm management practices were compared to standard cages. During an autumn-winter study involving only snorkel cages, high AGD-related gill scores were observed to decline when freshwater was pumped into snorkels, creating a freshwater surface layer for salmon to enter for self-treatment. In a spring-summer study incorporating snorkel and standard cages, snorkel cages were found to reduce new lice infestations by 84%. The deployment of snorkels and intermittent oxygen depletion detected within them in the spring-summer study did not alter fish welfare parameters. Overall, the results suggest snorkel technology has a place in the toolkit of commercial salmon sea-cage farmers co-managing salmon lice and amoebic gill disease outbreaks - two principal parasite issues facing the industry. Copyright © 2017 Elsevier B.V. All rights reserved.

Histopathological changes on the gills of asp (Aspius aspius) and European catfish (Silurus glanis) caused by Lamproglena pulchella and a Lamproglena sp. (Copepoda: Lernaeidae), respectively.

PubMed

Molnár, K; Avenant-Oldewage, A; Sellyei, B; Varga, Á; Székely, C

2018-01-01

In a parasitology survey of Hungarian fishes, heavy infections of parasitic copepods Lamproglena pulchella and a Lamproglena sp. were found in the gills of the asp and the European catfish, respectively. Individuals of both fish species were emaciated and infected with hundreds of Lamproglena. Copepods located close to the tip of gill filaments and formed a depression at the attachment sites. In histological sections, cell degenerations and local haemorrhages were present adjacent to the maxillipeds and where the maxillary claws pierced the gill tissue. Around maxillae and in the midgut of the Lamproglena, damaged piscine blood cells and remains of the gill tissue were observed. Host reaction was expressed by proliferation of epithelioid cells, increase in both number and size of goblet and mast cells and formation of giant cells. © 2017 John Wiley & Sons Ltd.

A new species of Ergasilus Nordmann, 1832 (Copepoda: Cyclopoida: Ergasilidae) from Bryconops giacopinii Fernández-Yépez (Characidae) in the Vichada River Basin, Colombia.

PubMed

Muriel-Hoyos, Felipe; Santana-Piñeros, Ana María; Cruz-Quintana, Yanis; Suárez-Morales, Eduardo

2015-11-01

A new copepod species, Ergasilus curticrus n. sp. is described based on 14 female specimens collected from the gills of the characid teleost Bryconops giacopinii Fernández-Yépez, captured in the Vichada River Basin in Colombia. The new species has a unique combination of characters including: (i) 2-segmented endopods in legs 1 and 4; (ii) a semi-pinnate, falciform seta on the terminal segment of the first leg exopod; (iii) a 1-segmented fourth leg exopod; (iv) a reduced fifth leg with a single seta; and (v) a circular structure fused to a groove near the lateral margins of the second pedigerous tergite. Only two other known congeners have a 1-segmented leg 4 exopod, E. coatiarus Araujo & Varella, 1998 and E. iheringi Tidd, 1942. Among other characters, they differ from the new species by the lack of a semi-pinnate, falciform seta on the terminal exopodal segment of leg 1 and in the structure and armature of the fifth leg. The prevalence of E. curticrus n. sp. was 13.6% and its mean abundance was 0.4 specimens per host. This is the first new species of Ergasilus Nordmann, 1832 described from the Orinoco River Basin.

Spatial and temporal distribution in density and biomass of two Pseudodiaptomus species (Copepoda: Calanoida) in the Caeté river estuary (Amazon region--North of Brazil).

PubMed

Magalhães, A; Costa, R M; Liang, T H; Pereira, L C C; Ribeiro, M J S

2006-05-01

Spatial and temporal density and biomass distribution of the planktonic copepods Pseudodiaptomus richardi and P. acutus along a salinity gradient were investigated in the Caeté River Estuary (North-Brazil) in June and December, 1998 (dry season) and in February and May, 1999 (rainy season). Copepod biomass was estimated using regression parameters based on the relation of dry weight and body length (prosome) of adult organisms. The Caeté River Estuary was characterized by high spatial and temporal variations in salinity (0.8-37.2). Exponential length-weight relationships were observed for both Pseudodiaptomus species. Density and biomass values oscillated between 0.28-46.18 ind. m-3 and 0.0022-0.3507 mg DW. m-3 for P. richardi; and between 0.01-17.02 ind. m-3 and 0.0005-0.7181 mg DW. m-3 for P. acutus. The results showed that the contribution of P. richardi for the secondary production in the Caeté River Estuary is more important in the limnetic zone than in other zones where euhaline-polyhaline regimes were predominant. However, it was not possible to observe a clear pattern of spatial and temporal distribution for P. acutus.

On some new species of Ancorabolidae Sars, 1909 from the Gulf of California: the genera Ceratonotus Sars, 1909, and Dendropsyllus Conroy-Dalton, 2003 (Crustacea, Copepoda, Harpacticoida).

PubMed

Gómez, Samuel; Díaz, Karen

2017-01-01

Two new species of two genera of the family Ancorabolidae, Ceratonotus elongatus sp. n. and Dendropsyllus californiensis sp. n. , found at 1642 m and 1759 m depth, respectively, in the Southern Trough of Guaymas Basin, are described. Ceratonotus elongatus sp. n. was attributed to that genus by a series of character states of which the lack of dendroid dorsal processes on the P6-bearing somite and the presence of such processes on the first abdominal somite were definitive. This species was observed to be very close to Ceratonotus thistlei Conroy-Dalton, 2003 from the San Diego Trough, and can be separated by a number of traits of which the elongated sensilla-bearing dorsal tubercles on the second abdominal somite in the new species was definitive. Dendropsyllus californiensis sp. n. has been placed within that genus given the presence of four geniculate setae on P1EXP2 and one seta on P1ENP2, one inner seta on P3EXP3, and lack of inner armature on P4EXP3. Dendropsyllus californiensis sp. n. appears to be more closely related to Dendropsyllus thomasi Conroy-Dalton, 2003 and Dendropsyllus magellanicus (George & Schminke, 1998) on account of the spinulose nature of the basis of the maxilliped, the two-segmented P4ENP, and the fused condition of the P5 baseoendopod and exopod, and seems to be even more closely related to Dendropsyllus thomasi by the degree of development of the lateroventral processes of the cephalothorax. Dendropsyllus californiensis sp. n. can be separated from its congeners by the relative length of the first antennulary segment, relative length of the caudal rami, and by the armature formula of P3ENP2.

A new species of Ergasilus von Nordmann, 1832 (Copepoda: Cyclopoida) from the gills of a dasyatid ray, Himantura oxyrhyncha (Sauvage, 1878) from West Kalimantan, Indonesia.

PubMed

Boxshall, Geoffrey A

2016-10-11

A new species of the cyclopoid copepod genus Ergasilus von Nordmann, 1832 is described based on material collected from the gills of an elasmobranch, Himantura oxyrhyncha (Sauvage, 1878), collected in the Java Sea off the coast of West Kalimantan, Indonesia. To justify the establishment of the new species, Ergasilus kimi sp. nov., detailed comparisons are made with the 28 congeneric species that share the combination of a 3-segmented leg 1 endopod and the presence of 2 setae on the free exopodal segment of leg 5. This is the fourth report of an Ergasilus species infecting an elasmobranch and it is concluded that each represents an independent colonization event of elasmobranchs as hosts.

Nucleospora cyclopteri n. sp., an intranuclear microsporidian infecting wild lumpfish, Cyclopterus lumpus L., in Icelandic waters

PubMed Central

2013-01-01

Background Commercial fisheries of lumpfish Cyclopterus lumpus have been carried out in Iceland for centuries. Traditionally the most valuable part is the eggs which are harvested for use as a caviar substitute. Previously reported parasitic infections from lumpfish include an undescribed intranuclear microsporidian associated with abnormal kidneys and mortalities in captive lumpfish in Canada. During Icelandic lumpfish fisheries in spring 2011, extensive enlargements to the kidneys were observed in some fish during processing. The aim of this study was to identify the pathogen responsible for these abnormalities. Methods Lumpfish from the Icelandic coast were examined for the causative agent of kidney enlargement. Fish were dissected and used in histological and molecular studies. Results Lumpfish, with various grades of clinical signs, were observed at 12 of the 43 sites sampled around Iceland. From a total of 77 fish examined, 18 had clear clinical signs, the most prominent of which was an extensive enlargement and pallor of the kidneys. The histopathology of the most severely affected fish consisted of extensive degeneration and necrosis of kidney tubules and vacuolar degeneration of the haematopoietic tissue. Intranuclear microsporidians were detected in all organs examined in fish with prominent clinical signs and most organs of apparently healthy fish using the new PCR and histological examination. One or multiple uniformly oval shaped spores measuring 3.12 ± 0.15 × 1.30 ± 0.12 μm were observed in the nucleus of affected lymphocytes and lymphocyte precursor cells. DNA sequencing provided a ribosomal DNA sequence that was strongly supported in phylogenetic analyses in a clade containing other microsporidian parasites from the Enterocytozoonidae, showing highest similarity to the intranuclear microsporidian Nucleospora salmonis. Conclusions Intranuclear microsporidian infections are common in wild caught lumpfish from around the Icelandic

Control of aedes vectors of dengue in three provinces of Vietnam by use of Mesocyclops (Copepoda) and community-based methods validated by entomologic, clinical, and serological surveillance.

PubMed

Kay, Brian H; Nam, Vu Sinh; Tien, Tran Van; Yen, Nguyen Thi; Phong, Tran Vu; Diep, Vu Thi Bich; Ninh, Truong Uyen; Bektas, Ahmet; Aaskov, John G

2002-01-01

We describe remarkable success in controlling dengue vectors, Aedes aegypti (L.) and Aedes albopictus (Skuse), in 6 communes with 11,675 households and 49,647 people in the northern provinces of Haiphong, Hung Yen, and Nam Dinh in Vietnam. The communes were selected for high-frequency use of large outdoor concrete tanks and wells. These were found to be the source of 49.6-98.4% of Ae. aegypti larvae, which were amenable to treatment with local Mesocyclops, mainly M. woutersi Van der Velde, M. aspericornis (Daday) and M. thermocyclopoides Harada. Knowledge, attitude, and practice surveys were performed to determine whether the communities viewed dengue and dengue hemorrhagic fever as a serious health threat; to determine their knowledge of the etiology, attitudes, and practices regarding control methods including Mesocyclops; and to determine their receptivity to various information methods. On the basis of the knowledge, attitude, and practice data, the community-based dengue control program comprised a system of local leaders, health volunteer teachers, and schoolchildren, supported by health professionals. Recycling of discards for economic gain was enhanced, where appropriate, and this, plus 37 clean-up campaigns, removed small containers unsuitable for Mesocyclops treatment. A previously successful eradication at Phan Boi village (Hung Yen province) was extended to 7 other villages forming Di Su commune (1,750 households) in the current study. Complete control was also achieved in Nghia Hiep (Hung Yen province) and in Xuan Phong (Nam Dinh province); control efficacy was > or = 99.7% in the other 3 communes (Lac Vien in Haiphong, Nghia Dong, and Xuan Kien in Nam Dinh). Although tanks and wells were the key container types of Ae. aegypti productivity, discarded materials were the source of 51% of the standing crop of Ae. albopictus. Aedes albopictus larvae were eliminated from the 3 Nam Dinh communes, and 86-98% control was achieved in the other 3 communes. Variable dengue attack rates made the clinical and serological comparison of control and untreated communes problematic, but these data indicate that clinical surveillance by itself is inadequate to monitor dengue transmission.

Retention and characteristics of microplastics in natural zooplankton taxa from the East China Sea.

PubMed

Sun, Xiaoxia; Liu, Tao; Zhu, Mingliang; Liang, Junhua; Zhao, Yongfang; Zhang, Bo

2018-05-30

The ubiquitous presence and persistence of microplastics (MPs) in aquatic environments have become of particular concern in recent years. Biological interactions are among the key processes that affect the impact and fate of MPs in the oceans. Zooplankton is one of the most sensitive taxa because their prey is approximately the same size as MPs. However, the status of MPs in zooplankton within natural marine environments remains largely unknown. By focusing on zooplankton in the East China Sea, the characteristics, bioaccumulated concentration, and retention of MPs for 10 zooplankton groups were systematically studied. Three types of MPs were found in zooplankton: fibres, pellets, and fragments. The fibres (54.6%) were more common than the other two types. The average lengths of the fibres, pellets, and fragments were 295.2 ± 348.6 μm, 20.3 ± 11.0 μm, and 82.4 ± 80.5 μm, respectively. Nineteen polymers were detected in the zooplankton via the Thermo Scientific Nicolet iN10 Infrared Microscope. Polymerized oxidized organic material and polyester were dominant, accounting for 35.9% and 25.6% of the polymers, respectively. The bioaccumulated concentration of MPs in the 10 zooplankton taxa varied from 0.13 pieces/zooplankton for Copepoda to 0.35 pieces/zooplankton for Pteropoda. The bioaccumulated concentration was negatively correlated with the abundance of zooplankton, showing a significant biological dilution effect. The bioaccumulated concentration was also influenced by the feeding mode of zooplankton, showing a trend of omnivorous > carnivorous > herbivorous. High retention of MPs was found in the zooplankton community of the East China Sea, achieving 19.7 ± 22.4 pieces/m 3 . This is much higher than the MP retention in zooplankton from other reported sea areas. By revealing the characteristics and retention of MPs in the natural zooplankton taxa from the East China Sea, this research identified the influence that MPs have

Limnological study of Lake Shastina, Siskiyou County, California

USGS Publications Warehouse

Dong, Alex E.; Beatty, Kenneth W.; Averett, Robert C.

1974-01-01

about 5 million cells per litre.Zooplankton numbers were greatest in March, July, and September, with lesser concentrations in June. Three major zooplankton groups, Cladocera, Copepoda, and Rotifera, were present. The major groups of benthic organisms were Oligochaeta, Chironomidae, and Chaoborus, with numbers ranging from 3350, 890, and 8450 per square metre, respectively.A discussion on algal control is included.

Composition of abyssal macrofauna along the Vema Fracture Zone and the hadal Puerto Rico Trench, northern tropical Atlantic

NASA Astrophysics Data System (ADS)

Brandt, A.; Frutos, I.; Bober, S.; Brix, S.; Brenke, N.; Guggolz, T.; Heitland, N.; Malyutina, M.; Minzlaff, U.; Riehl, T.; Schwabe, E.; Zinkann, A.-C.; Linse, K.

2018-02-01

We analyzed composition and variations in benthic macrofaunal communities along a transect of the entire length of the Vema-Fracture Zone on board of RV Sonne (SO-237) between December 2014 and January 2015 in order to test whether the Mid-Atlantic Ridge serves as a barrier limiting benthic taxon distribution in the abyssal basins on both sides of the ridge or whether the fracture zone permits the migration of species between the western and eastern abyssal Atlantic basins. The Puerto Rico Trench, much deeper than the surrounding abyssal West Atlantic, was sampled to determine whether the biodiversity of its hadal macrofauna differs from that of the abyssal Atlantic. The composition of the macrofauna from the epibenthic sledge catches yielded a total of 21,332 invertebrates. Crustacea occurred most frequently (59%) with 12,538 individuals followed by Annelida (mostly Polychaeta) (26%) with 5491 individuals, Mollusca (7%) with 1458 individuals, Echinodermata (4%) with 778 individuals, Nematoda (2%) with 502 individuals and Chaetognatha (1%) with 152 and Porifera (1%) with 131 individuals. All other taxa occurred with overall less than ten individuals (Hemichordata, Phoronida, Priapulida, Brachiopoda, invertebrate Chordata, Echiurida, Foraminifera (here refereed to macrofaunal Komokiacea only), Chelicerata, Platyhelminthes). Within the Crustacea, Peracarida (62.6%) with 7848 individuals and Copepoda (36.1%) with 44,526 individuals were the most abundant taxa. Along the abyssal Vema-Fracture Zone macrofaunal abundances (ind./1000 m2) were generally higher on the eastern side, while the highest normalized abundance value was reported in the Puerto Rico Trench at abyssal station 14-1 2313 individuals/1000 m2. The lowest abundance was reported at station 11-4 with 120 ind./1000 m2 located at the western side of the Vema-Fracture Zone. The number of major macrofaunal taxa (phylum, class) ranged between five (stations 12-5, 13-4 and 13-5 at hadal depths in the Puerto Rico

Observing copepods through a genomic lens

PubMed Central

2011-01-01

Background Copepods outnumber every other multicellular animal group. They are critical components of the world's freshwater and marine ecosystems, sensitive indicators of local and global climate change, key ecosystem service providers, parasites and predators of economically important aquatic animals and potential vectors of waterborne disease. Copepods sustain the world fisheries that nourish and support human populations. Although genomic tools have transformed many areas of biological and biomedical research, their power to elucidate aspects of the biology, behavior and ecology of copepods has only recently begun to be exploited. Discussion The extraordinary biological and ecological diversity of the subclass Copepoda provides both unique advantages for addressing key problems in aquatic systems and formidable challenges for developing a focused genomics strategy. This article provides an overview of genomic studies of copepods and discusses strategies for using genomics tools to address key questions at levels extending from individuals to ecosystems. Genomics can, for instance, help to decipher patterns of genome evolution such as those that occur during transitions from free living to symbiotic and parasitic lifestyles and can assist in the identification of genetic mechanisms and accompanying physiological changes associated with adaptation to new or physiologically challenging environments. The adaptive significance of the diversity in genome size and unique mechanisms of genome reorganization during development could similarly be explored. Genome-wide and EST studies of parasitic copepods of salmon and large EST studies of selected free-living copepods have demonstrated the potential utility of modern genomics approaches for the study of copepods and have generated resources such as EST libraries, shotgun genome sequences, BAC libraries, genome maps and inbred lines that will be invaluable in assisting further efforts to provide genomics tools for

A compilation of quantitative functional traits for marine and freshwater crustacean zooplankton.

PubMed

Hébert, Marie-Pier; Beisner, Beatrix E; Maranger, Roxane

2016-04-01

This data compilation synthesizes 8609 individual observations and ranges of 13 traits from 201 freshwater and 191 marine crustacean taxa belonging to either Copepoda or Cladocera, two important zooplankton groups across all major aquatic habitats. Most data were gathered from the literature, with the balance being provided by zooplankton ecologists. With the aim of more fully assessing zooplankton effects on elemental processes such as nitrogen (N), phosphorus (P) and carbon (C) stocks and fluxes in aquatic ecosystems, this data set provides information on the following traits: body size (length and mass), trophic group, elemental and biochemical corporal composition (N, P, C, lipid and protein content), respiration rates, N- and P-excretion rates, as well as stoichiometric ratios. Although relationships for zooplankton metabolism as a function of body mass or requirements have been explored in the past three decades, data have not been systematically compiled nor examined from an integrative and large-scale perspective across crustacean taxa and habitat types. While this contribution likely represents the most comprehensive assembly of traits for both marine and freshwater species, this data set is not exhaustive either. As a result, this compilation also identifies knowledge gaps: a fact that should encourage researchers to disclose information they may have to help complete such databases. This trait matrix is made available for the first time in this data paper; prior to its release, the data set has been analyzed in a meta-analysis published as a companion paper. This data set should prove extremely valuable for aquatic ecologists for trait-based characterization of plankton community structure as well as biogeochemical modeling. These data are also well-suited for deriving shortcut relationships that predict more difficult to measure trait values, most of which can be directly related to ecosystem properties (i.e., effect traits), from simpler traits (e

Determination and validation of an aquatic Maximum Acceptable Concentration-Environmental Quality Standard (MAC-EQS) value for the agricultural fungicide azoxystrobin.

PubMed

Rodrigues, Elsa Teresa; Pardal, Miguel Ângelo; Gante, Cristiano; Loureiro, João; Lopes, Isabel

2017-02-01

The main goal of the present study was to determine and validate an aquatic Maximum Acceptable Concentration-Environmental Quality Standard (MAC-EQS) value for the agricultural fungicide azoxystrobin (AZX). Assessment factors were applied to short-term toxicity data using the lowest EC 50 and after the Species Sensitivity Distribution (SSD) method. Both ways of EQS generation were applied to a freshwater toxicity dataset for AZX based on available data, and to marine toxicity datasets for AZX and Ortiva ® (a commercial formulation of AZX) obtained by the present study. A high interspecific variability in AZX sensitivity was observed in all datasets, being the copepoda Eudiaptomus graciloides (LC 50,48h  = 38 μg L -1 ) and the gastropod Gibbula umbilicalis (LC 50,96h  = 13 μg L -1 ) the most sensitive freshwater and marine species, respectively. MAC-EQS values derived using the lowest EC 50 (≤0.38 μg L -1 ) were more protective than those derived using the SSD method (≤3.2 μg L -1 ). After comparing the MAC-EQS values estimated in the present study to the smallest AA-EQS available, which protect against the occurrence of prolonged exposure of AZX, the MAC-EQS values derived using the lowest EC 50 were considered overprotective and a MAC-EQS of 1.8 μg L -1 was validated and recommended for AZX for the water column. This value was derived from marine toxicity data, which highlights the importance of testing marine organisms. Moreover, Ortiva affects the most sensitive marine species to a greater extent than AZX, and marine species are more sensitive than freshwater species to AZX. A risk characterization ratio higher than one allowed to conclude that AZX might pose a high risk to the aquatic environment. Also, in a wider conclusion, before new pesticides are approved, we suggest to improve the Tier 1 prospective Ecological Risk Assessment by increasing the number of short-term data, and apply the SSD approach, in order to ensure the safety of

A new species of Labidocera (Copepoda, Calanoida, Pontellidae) collected from Okinawa, southwestern Japan, with establishment of five Indo-West Pacific species groups in the L.detruncata species complex.

PubMed

Hirabayashi, Takeshi; Ohtsuka, Susumu

2014-01-01

Labidocerachuraumi sp. n. is described from Okinawa, southwestern Japan. The female of the new species differs from other congeners in genital compound somite with right postero-lateral and left antero-lateral processes. The male is distinguished from other congeners by the structure of the fifth leg. This new species is assigned to a newly proposed species group, the Labidoceramadurae species group, within the Labidoceradetruncata species complex. In this species complex five Indo-West Pacific species groups are recognized (cervi, detruncata, gangetica, madurae, and pavo) and defined on the basis of difference in sexual dimorphism.

A new species of Labidocera (Copepoda, Calanoida, Pontellidae) collected from Okinawa, southwestern Japan, with establishment of five Indo-West Pacific species groups in the L. detruncata species complex

PubMed Central

Hirabayashi, Takeshi; Ohtsuka, Susumu

2014-01-01

Abstract Labidocera churaumi sp. n. is described from Okinawa, southwestern Japan. The female of the new species differs from other congeners in genital compound somite with right postero-lateral and left antero-lateral processes. The male is distinguished from other congeners by the structure of the fifth leg. This new species is assigned to a newly proposed species group, the Labidocera madurae species group, within the Labidocera detruncata species complex. In this species complex five Indo-West Pacific species groups are recognized (cervi, detruncata, gangetica, madurae, and pavo) and defined on the basis of difference in sexual dimorphism. PMID:25349514

Infectious salmon anaemia virus (ISAV) in Chilean Atlantic salmon (Salmo salar) aquaculture: emergence of low pathogenic ISAV-HPR0 and re-emergence of virulent ISAV-HPR∆: HPR3 and HPR14.

PubMed

Godoy, Marcos G; Kibenge, Molly J T; Suarez, Rudy; Lazo, Eduardo; Heisinger, Alejandro; Aguinaga, Javier; Bravo, Diego; Mendoza, Julio; Llegues, Katerina O; Avendaño-Herrera, Rubén; Vera, Cristian; Mardones, Fernando; Kibenge, Frederick S B

2013-11-23

Infectious salmon anaemia (ISA) is a serious disease of marine-farmed Atlantic salmon (Salmo salar) caused by ISA virus (ISAV), which belongs to the genus Isavirus, family Orthomyxoviridae. ISA is caused by virulent ISAV strains with deletions in a highly polymorphic region (HPR) of the hemagglutinin-esterase (HE) protein (designated virulent ISAV-HPR∆). This study shows the historic dynamics of ISAV-HPR∆ and ISAV-HPR0 in Chile, the genetic relationship among ISAV-HPR0 reported worldwide and between ISAV-HPR0 and ISAV-HPR∆ in Chile, and reports the 2013 ISA outbreak in Chile. The first ISA outbreak in Chile occurred from mid-June 2007 to 2010 and involved the virulent ISAV-HPR7b, which was then replaced by a low pathogenic ISAV-HPR0 variant. We analyzed this variant in 66 laboratory-confirmed ISAV-HPR0 cases in Chile in comparison to virulent ISAV-HPR∆ that caused two new ISA outbreaks in April 2013. Multiple alignment and phylogenetic analysis of HE sequences from all ISAV-HPR0 viruses allowed us to identify three genomic clusters, which correlated with three residue patterns of ISAV-HPR0 (360PST362, 360PAN362 and 360PAT362) in HPR. The virus responsible for the 2013 ISAV-HPR∆ cases in Chile belonged to ISAV-HPR3 and ISAV-HPR14, and in phylogenetic analyses, both clustered with the ISAV-HPR0 found in Chile. The ISAV-HPR14 had the ISAV-HPR0 residue pattern 360PAT362, which is the only type of ISAV-HPR0 variant found in Chile. This suggested to us that the 2013 ISAV-HPR∆ re-emerged from ISAV-HPR0 that is enzootic in Chilean salmon aquaculture and were not new introductions of virulent ISAV-HPR∆ to Chile. The clinical presentations and diagnostic evidence of the 2013 ISA cases indicated a mixed infection of ISAV with the ectoparasite Caligus rogercresseyi and the bacterium Piscirickettsia salmonis, which underscores the need for active ISAV surveillance in areas where ISAV-HPR0 is enzootic, to ensure early detection and control of new ISA outbreaks, as

Infectious salmon anaemia virus (ISAV) in Chilean Atlantic salmon (Salmo salar) aquaculture: emergence of low pathogenic ISAV-HPR0 and re-emergence of virulent ISAV-HPR∆: HPR3 and HPR14

PubMed Central

2013-01-01

Abstact Infectious salmon anaemia (ISA) is a serious disease of marine-farmed Atlantic salmon (Salmo salar) caused by ISA virus (ISAV), which belongs to the genus Isavirus, family Orthomyxoviridae. ISA is caused by virulent ISAV strains with deletions in a highly polymorphic region (HPR) of the hemagglutinin-esterase (HE) protein (designated virulent ISAV-HPR∆). This study shows the historic dynamics of ISAV-HPR∆ and ISAV-HPR0 in Chile, the genetic relationship among ISAV-HPR0 reported worldwide and between ISAV-HPR0 and ISAV-HPR∆ in Chile, and reports the 2013 ISA outbreak in Chile. The first ISA outbreak in Chile occurred from mid-June 2007 to 2010 and involved the virulent ISAV-HPR7b, which was then replaced by a low pathogenic ISAV-HPR0 variant. We analyzed this variant in 66 laboratory-confirmed ISAV-HPR0 cases in Chile in comparison to virulent ISAV-HPR∆ that caused two new ISA outbreaks in April 2013. Multiple alignment and phylogenetic analysis of HE sequences from all ISAV-HPR0 viruses allowed us to identify three genomic clusters, which correlated with three residue patterns of ISAV-HPR0 (360PST362, 360PAN362 and 360PAT362) in HPR. The virus responsible for the 2013 ISAV-HPR∆ cases in Chile belonged to ISAV-HPR3 and ISAV-HPR14, and in phylogenetic analyses, both clustered with the ISAV-HPR0 found in Chile. The ISAV-HPR14 had the ISAV-HPR0 residue pattern 360PAT362, which is the only type of ISAV-HPR0 variant found in Chile. This suggested to us that the 2013 ISAV-HPR∆ re-emerged from ISAV-HPR0 that is enzootic in Chilean salmon aquaculture and were not new introductions of virulent ISAV-HPR∆ to Chile. The clinical presentations and diagnostic evidence of the 2013 ISA cases indicated a mixed infection of ISAV with the ectoparasite Caligus rogercresseyi and the bacterium Piscirickettsia salmonis, which underscores the need for active ISAV surveillance in areas where ISAV-HPR0 is enzootic, to ensure early detection and control of new ISA

Spring evolution of Pseudocalanus spp. abundance on Georges Bank based on molecular discrimination of P. moultoni and P. newmani1

NASA Astrophysics Data System (ADS)

Bucklin, Ann; Guarnieri, Maria; McGillicuddy, Dennis J.; Sean Hill, R.

The planktonic copepod sibling species Pseudocalanus moultoni and P. newmani (Crustacea, Copepoda) are abundant in waters over Georges Bank from late winter until mid-summer and are thought to reproduce throughout this period. The two species cannot be reliably distinguished using morphological characters, but are readily identified and distinguished by simple, rapid, and inexpensive molecular protocols based on sequence variation of mitochondrial DNA (mtDNA). DNA sequence variation of a portion of the mitochondrial cytochrome oxidase I (mtCOI) confirmed the presence of P. moultoni and P. newmani on Georges Bank; the mtCOI sequences were used to design species-specific oligonucleotide primers for use in a competitive multiplexed species-specific polymerase chain reaction (PCR). Species-specific PCR was used to determine the relative abundances of the two species in sub-samples of zooplankton collections from US GLOBEC Georges Bank Study Broadscale Surveys from February to June, 1997. Based on monthly visualizations, we inferred the spring evolution of the two species' distributions and abundances on Georges Bank. Both species' overall abundances increased from February to May or June: maximum abundance of P. moultoni was 38,061 m -2 in surface waters on the crest of Georges Bank in June; maximum abundance of P. newmani was 13,854 m -2 in subsurface waters on the Northeast Peak in April. The Peak in distribution of P. moultoni shifted from Georges Basin in April, to the northern edge of the Bank in May, to the center of the Bank in June. In contrast, P. newmani was more abundant to the south and east of the Bank. Beginning in April, P. newmani occurred on the Bank but was less abundant and less widely-distributed than P. moultoni; P. newmani abundance peaked in May and declined somewhat in June. Females of the species differed in their patterns of distribution and abundance, with P. moultoni always the more abundant species on the crest of the Bank. The spring

A Synoptic Assessment of the Amazon River-Ocean Continuum during Boreal Autumn: From Physics to Plankton Communities and Carbon Flux.

PubMed

Araujo, Moacyr; Noriega, Carlos; Hounsou-Gbo, Gbekpo Aubains; Veleda, Doris; Araujo, Julia; Bruto, Leonardo; Feitosa, Fernando; Flores-Montes, Manuel; Lefèvre, Nathalie; Melo, Pedro; Otsuka, Amanda; Travassos, Keyla; Schwamborn, Ralf; Neumann-Leitão, Sigrid

2017-01-01

The Amazon generates the world's largest offshore river plume, which covers extensive areas of the tropical Atlantic. The data and samples in this study were obtained during the oceanographic cruise Camadas Finas III in October 2012 along the Amazon River-Ocean Continuum (AROC). The cruise occurred during boreal autumn, when the river plume reaches its maximum eastward extent. In this study, we examine the links between physics, biogeochemistry and plankton community structure along the AROC. Hydrographic results showed very different conditions, ranging from shallow well-mixed coastal waters to offshore areas, where low salinity Amazonian waters mix with open ocean waters. Nutrients, mainly [Formula: see text] and [Formula: see text], were highly depleted in coastal regions, and the magnitude of primary production was greater than that of respiration (negative apparent oxygen utilization). In terms of phytoplankton groups, diatoms dominated the region from the river mouth to the edge of the area affected by the North Brazil Current (NBC) retroflection (with chlorophyll a concentrations ranging from 0.02 to 0.94 mg m -3 ). The North Equatorial Counter Current (NECC) region, east of retroflection, is fully oligotrophic and the most representative groups are Cyanobacteria and dinoflagellates. Additionally, in this region, blooms of cyanophyte species were associated with diatoms and Mesozooplankton (copepods). A total of 178 zooplankton taxa were observed in this area, with Copepoda being the most diverse and abundant group. Two different zooplankton communities were identified: a low-diversity, high-abundance coastal community and a high-diversity, low-abundance oceanic community offshore. The CO 2 fugacity (fCO 2 sw), calculated from total alkalinity (1,450 < TA < 2,394 μmol kg -1 ) and dissolved inorganic carbon (1,303 < DIC < 2,062 μmol kg -1 ) measurements, confirms that the Amazon River plume is a sink of atmospheric CO 2 in areas with salinities <35 psu

Comparison of laboratory single species and field population-level effects of the pyrethroid insecticide lambda-cyhalothrin on freshwater invertebrates.

PubMed

Schroer, A F W; Belgers, J D M; Brock, T C M; Matser, A M; Maund, S J; Van den Brink, P J

2004-04-01

The toxicity of the pyrethroid insecticide lambda-cyhalothrin to freshwater invertebrates has been investigated using data from short-term laboratory toxicity tests and in situ bioassays and population-level effects in field microcosms. In laboratory tests, patterns of toxicity were consistent with previous data on pyrethroids. The midge Chaoborus obscuripes was most sensitive (48- and 96-h EC50 = 2.8 ng/L). Other insect larvae (Hemiptera, Ephemeroptera) and macrocrustacea (Amphipoda, Isopoda) were also relatively sensitive, with 48- and 96-h EC50 values between 10 and 100 ng/L. Generally, microcrustacea (Cladocera, Copepoda) and larvae of certain insect groups (Odonata and Chironomidae) were less sensitive, with 48-h EC50 values higher than 100 ng/L. Mollusca and Plathelminthes were insensitive and were unaffected at concentrations at and above the water solubility (5 microg/L). Generally, the EC50 values based on initial population responses in field enclosures were similar to values derived from laboratory tests with the same taxa. Also, the corresponding fifth and tenth percentile hazard concentrations (HC5 and HC10) were similar (laboratory HC5 = 2.7 ng/L and field HC5 = 4.1 ng/L; laboratory and field HC10 = 5.1 ng/L), at least when based on the same sensitive taxonomic groups (insects and crustaceans) and when a similar concentration range was taken into account. In the three field enclosure experiments and at a treatment level of 10 ng/L, consistent effects were observed for only one population (Chaoborus obscuripes), with recovery taking place within 3 to 6 weeks. The laboratory HC5 (2.7 ng/L) and HC10 (5.1 ng/L) based on acute EC50 values of all aquatic arthropod taxa were both lower than this 10 ng/L, a concentration that might represent the "regulatory acceptable concentration." The HC5 and HC10 values in this study in The Netherlands (based on static laboratory tests with freshwater arthropods) were very similar to those derived from a previous study in

A Synoptic Assessment of the Amazon River-Ocean Continuum during Boreal Autumn: From Physics to Plankton Communities and Carbon Flux

PubMed Central

Araujo, Moacyr; Noriega, Carlos; Hounsou-gbo, Gbekpo Aubains; Veleda, Doris; Araujo, Julia; Bruto, Leonardo; Feitosa, Fernando; Flores-Montes, Manuel; Lefèvre, Nathalie; Melo, Pedro; Otsuka, Amanda; Travassos, Keyla; Schwamborn, Ralf; Neumann-Leitão, Sigrid

2017-01-01

The Amazon generates the world's largest offshore river plume, which covers extensive areas of the tropical Atlantic. The data and samples in this study were obtained during the oceanographic cruise Camadas Finas III in October 2012 along the Amazon River-Ocean Continuum (AROC). The cruise occurred during boreal autumn, when the river plume reaches its maximum eastward extent. In this study, we examine the links between physics, biogeochemistry and plankton community structure along the AROC. Hydrographic results showed very different conditions, ranging from shallow well-mixed coastal waters to offshore areas, where low salinity Amazonian waters mix with open ocean waters. Nutrients, mainly NO3− and SiO2−, were highly depleted in coastal regions, and the magnitude of primary production was greater than that of respiration (negative apparent oxygen utilization). In terms of phytoplankton groups, diatoms dominated the region from the river mouth to the edge of the area affected by the North Brazil Current (NBC) retroflection (with chlorophyll a concentrations ranging from 0.02 to 0.94 mg m−3). The North Equatorial Counter Current (NECC) region, east of retroflection, is fully oligotrophic and the most representative groups are Cyanobacteria and dinoflagellates. Additionally, in this region, blooms of cyanophyte species were associated with diatoms and Mesozooplankton (copepods). A total of 178 zooplankton taxa were observed in this area, with Copepoda being the most diverse and abundant group. Two different zooplankton communities were identified: a low-diversity, high-abundance coastal community and a high-diversity, low-abundance oceanic community offshore. The CO2 fugacity (fCO2sw), calculated from total alkalinity (1,450 < TA < 2,394 μmol kg−1) and dissolved inorganic carbon (1,303 < DIC < 2,062 μmol kg−1) measurements, confirms that the Amazon River plume is a sink of atmospheric CO2 in areas with salinities <35 psu, whereas, in regions with

Addition of a selective breeding program for resistance to sea lice Lepeophtheirus salmonis (Kroyer 1838) to existing lines of Atlantic Salmon, Salmo salar L., at the USDA's National Cold Water Marine Aquaculture Center

USDA-ARS?s Scientific Manuscript database

Sea lice are likely the single most economically costly pathogen that has faced the salmon farming industry over the past 40 years. The most recent economic estimates put the annual cost of sea lice at just under $500 million USD in 2006. This is likely an underestimate of the current costs to indus...

An annotated list of fish parasites (Isopoda, Copepoda, Monogenea, Digenea, Cestoda, Nematoda) collected from Snappers and Bream (Lutjanidae, Nemipteridae, Caesionidae) in New Caledonia confirms high parasite biodiversity on coral reef fish

PubMed Central

2012-01-01

Background Coral reefs are areas of maximum biodiversity, but the parasites of coral reef fishes, and especially their species richness, are not well known. Over an 8-year period, parasites were collected from 24 species of Lutjanidae, Nemipteridae and Caesionidae off New Caledonia, South Pacific. Results Host-parasite and parasite-host lists are provided, with a total of 207 host-parasite combinations and 58 parasite species identified at the species level, with 27 new host records. Results are presented for isopods, copepods, monogeneans, digeneans, cestodes and nematodes. When results are restricted to well-sampled reef fish species (sample size > 30), the number of host-parasite combinations is 20–25 per fish species, and the number of parasites identified at the species level is 9–13 per fish species. Lutjanids include reef-associated fish and deeper sea fish from the outer slopes of the coral reef: fish from both milieus were compared. Surprisingly, parasite biodiversity was higher in deeper sea fish than in reef fish (host-parasite combinations: 12.50 vs 10.13, number of species per fish 3.75 vs 3.00); however, we identified four biases which diminish the validity of this comparison. Finally, these results and previously published results allow us to propose a generalization of parasite biodiversity for four major families of reef-associated fishes (Lutjanidae, Nemipteridae, Serranidae and Lethrinidae): well-sampled fish have a mean of 20 host-parasite combinations per fish species, and the number of parasites identified at the species level is 10 per fish species. Conclusions Since all precautions have been taken to minimize taxon numbers, it is safe to affirm than the number of fish parasites is at least ten times the number of fish species in coral reefs, for species of similar size or larger than the species in the four families studied; this is a major improvement to our estimate of biodiversity in coral reefs. Our results suggest that extinction of a coral reef fish species would eventually result in the coextinction of at least ten species of parasites. PMID:22947621

An annotated list of fish parasites (Isopoda, Copepoda, Monogenea, Digenea, Cestoda, Nematoda) collected from Snappers and Bream (Lutjanidae, Nemipteridae, Caesionidae) in New Caledonia confirms high parasite biodiversity on coral reef fish.

PubMed

Justine, Jean-Lou; Beveridge, Ian; Boxshall, Geoffrey A; Bray, Rodney A; Miller, Terrence L; Moravec, František; Trilles, Jean-Paul; Whittington, Ian D

2012-09-04

Coral reefs are areas of maximum biodiversity, but the parasites of coral reef fishes, and especially their species richness, are not well known. Over an 8-year period, parasites were collected from 24 species of Lutjanidae, Nemipteridae and Caesionidae off New Caledonia, South Pacific. Host-parasite and parasite-host lists are provided, with a total of 207 host-parasite combinations and 58 parasite species identified at the species level, with 27 new host records. Results are presented for isopods, copepods, monogeneans, digeneans, cestodes and nematodes. When results are restricted to well-sampled reef fish species (sample size > 30), the number of host-parasite combinations is 20-25 per fish species, and the number of parasites identified at the species level is 9-13 per fish species. Lutjanids include reef-associated fish and deeper sea fish from the outer slopes of the coral reef: fish from both milieus were compared. Surprisingly, parasite biodiversity was higher in deeper sea fish than in reef fish (host-parasite combinations: 12.50 vs 10.13, number of species per fish 3.75 vs 3.00); however, we identified four biases which diminish the validity of this comparison. Finally, these results and previously published results allow us to propose a generalization of parasite biodiversity for four major families of reef-associated fishes (Lutjanidae, Nemipteridae, Serranidae and Lethrinidae): well-sampled fish have a mean of 20 host-parasite combinations per fish species, and the number of parasites identified at the species level is 10 per fish species. Since all precautions have been taken to minimize taxon numbers, it is safe to affirm than the number of fish parasites is at least ten times the number of fish species in coral reefs, for species of similar size or larger than the species in the four families studied; this is a major improvement to our estimate of biodiversity in coral reefs. Our results suggest that extinction of a coral reef fish species would eventually result in the coextinction of at least ten species of parasites.

A critical life stage of the Atlantic salmon Salmo salar: behaviour and survival during the smolt and initial post-smolt migration.

PubMed

Thorstad, E B; Whoriskey, F; Uglem, I; Moore, A; Rikardsen, A H; Finstad, B

2012-07-01

The anadromous life cycle of Atlantic salmon Salmo salar involves long migrations to novel environments and challenging physiological transformations when moving between salt-free and salt-rich waters. In this article, (1) environmental factors affecting the migration behaviour and survival of smolts and post-smolts during the river, estuarine and early marine phases, (2) how behavioural patterns are linked to survival and (3) how anthropogenic factors affect migration and survival are synthesized and reviewed based on published literature. The timing of the smolt migration is important in determining marine survival. The timing varies among rivers, most likely as a consequence of local adaptations, to ensure sea entry during optimal periods. Smolts and post-smolts swim actively and fast during migration, but in areas with strong currents, their own movements may be overridden by current-induced transport. Progression rates during the early marine migration vary between 0.4 and 3.0 body lengths s(-1) relative to the ground. Reported mortality is 0.3-7.0% (median 2.3) km(-1) during downriver migration, 0.6-36% (median 6.0) km(-1) in estuaries and 0.3-3.4% (median 1.4) km(-1) in coastal areas. Estuaries and river mouths are the sites of the highest mortalities, with predation being a common cause. The mortality rates varied more among studies in estuaries than in rivers and marine areas, which probably reflects the huge variation among estuaries in their characteristics. Behaviour and survival during migration may also be affected by pollution, fish farming, sea lice Lepeophtheirus salmonis, hydropower development and other anthropogenic activities that may be directly lethal, delay migration or have indirect effects by inhibiting migration. Total mortality reported during early marine migration (up to 5-230 km from the river mouths) in the studies available to date varies between 8 and 71%. Hence, the early marine migration is a life stage with high mortalities, due

Endemism of subterranean Diacyclops in Korea and Japan, with descriptions of seven new species of the languidoides-group and redescriptions of D. brevifurcus Ishida, 2006 and D. suoensis Ito, 1954 (Crustacea, Copepoda, Cyclopoida)

PubMed Central

Karanovic, Tomislav; Grygier, Mark J.; Lee, Wonchoel

2013-01-01

Abstract Copepods have been poorly studied in subterranean habitats in Korea. Previous records have indicated mostly the presence of species already described from Japan, with very few endemic elements. This commonality has usually been explained by repeated dispersal across the land bridges that connected the two countries several times during the Pleistocene glacial cycles. However, the Korean Peninsula is known for pockets of Cambrian and Ordovician carbonate rocks, with more than 1,000 caves already having been explored. The relative isolation of these carbonate pockets makes for an enormous speciation potential, and the development of a high level of short-range endemism of subterranean copepods should be expected. Representatives of the genus Diacyclops Kiefer, 1927 are here investigated from a range of subterranean habitats in South Korea, with comparative material sampled from central Honshu in Japan. Morphological analyses of microcharacters, many of which are used in cyclopoid taxonomy for the first time herein, reveal high diversity in both countries. No subterranean species is found in common, although the existence of four sibling species pairs in Korea and Japan may be indicative of relatively recent speciation. We describe seven new stygobiotic species, including three from Korea (Diacyclops hanguk sp. n., Diacyclops leeae sp. n., and Diacyclops parasuoensis sp. n.) and four from Japan (Diacyclops hisuta sp. n., Diacyclops ishidai sp. n., Diacyclops parahanguk sp. n., and Diacyclops pseudosuoensis sp. n.). Diacyclops hanguk, Diacyclops parasuoensis, Diacyclops ishidai, and Diacyclops parahanguk are described from newly collected material, while the other three new species are proposed for specimens previously identified as other, widely distributed species. Diacyclops brevifurcus Ishida, 2006 is redescribed from the holotype female, and Diacyclops suoensis Ito, 1954 is redescribed from material newly collected near the ancient Lake Biwa in Japan. This research provides evidence for the importance of subterranean habitats as reservoirs of biodiversity, and also demonstrates the inadequacy of current morphological methods of identifying closely related species of copepods. The disproportionately high diversity discovered around Lake Biwa provides further evidence in support of the hypothesis about the role of ancient lakes as biodiversity pumps for subterranean habitats. A key to the East Asian species of the languidoides-group is provided. PMID:23653520

New record and redescription of Calanopia thompsoni A. Scott, 1909 (Copepoda, Calanoida, Pontellidae) from the Red Sea, with notes on the taxonomic status of C. parathompsoni Gaudy, 1969 and a key to species.

PubMed

Al-Aidaroos, Ali M; Salama, Adnan J; El-Sherbiny, Mohsen M

2016-01-01

During a plankton sampling programme around Al-Wajh area, Saudi Arabian coast of the northern Red Sea, a copepod Calanopia thompsoni A. Scott, 1909 (Calanoida: Pontellidae) was reported for the first time in the Red Sea. Both sexes are fully redescribed and compared to previous descriptions as well as the closely related species, Calanopia parathompsoni. The zoogeographical distribution of the species confirms that it is of Indo-Pacific origin. A dichotomous key for the identification of males and females of the species of Calanopia is included.

First report of the presence of Acartiabispinosa Carl, 1907 (Copepoda, Calanoida) in a semi-enclosed Bay (Sharm El-Maya), northern Red Sea with some notes on its seasonal variation in abundance and body size.

PubMed

El-Sherbiny, Mohsen M; Al-Aidaroos, Ali M

2014-01-01

The calanoid copepod, Acartiabispinosa Carl, 1907, is reported for the first time in the Red Sea, where it is found to be an important copepod in the mesozooplankton community structure of the Sharm El-Maya Bay. Female and male are fully redescribed and illustrated of as the mouthparts of this species have never previously been described and figured. Acartiabispinosa was collected in the plankton samples throughout the year and showed two peaks of abundance, a pronounced one in April (4234 individuals m(-3)), and second smaller peak during November (1784 individuals m(-3)). The average total length of females varied between 1.32 and 1.53 mm at the end of June and January respectively. For males, the average total length fluctuated between 1.07 and 1.16 mm at end of June and March respectively. Temperature showed an inverse relationship with the body length (P > 0.001) and seemed to be one of the prime factors affecting the body length of both sexes.

Effects of structural marsh management and salinity on invertebrate prey of waterbirds in marsh ponds during winter on the Gulf Coast Chenier Plain

USGS Publications Warehouse

Bolduc, F.; Afton, A.D.

2003-01-01

. Furthermore, as predicted, an a priori MANOVA contrast indicated that biomass of a single invertebrate class adapted to low salinity (Oligochaeta, 200 to 999 ??m) was greater in ponds of IF marshes than in those of IO and IM marshes. A canonical correspondence analysis indicated that variation in salinity and O2 penetration best explained differences among sites that maximized biomass of the common invertebrate classes. Salinity was positively correlated with the silt-clay fraction, O2, and O2 penetration, and negatively correlated with water depth, sediment hardness, carbon, and C:N. Nematoda, Foraminifera, and Copepoda generally were associated with UM marsh ponds and high salinity, whereas other invertebrate classes were distributed among impounded marsh ponds and associated with lower salinity. Our results suggest that SMM and salinity have relatively small effects on invertebrate prey of wintering waterbirds in marsh ponds because they affect biomass of Nematoda and Oligochaeta, and few waterbirds consume these invertebrates. ?? 2003, The Society of Wetland Scientists.

First report of the presence of Acartia bispinosa Carl, 1907 (Copepoda, Calanoida) in a semi-enclosed Bay (Sharm El-Maya), northern Red Sea with some notes on its seasonal variation in abundance and body size

PubMed Central

El-Sherbiny, Mohsen M.; Al-Aidaroos, Ali M.

2014-01-01

Abstract The calanoid copepod, Acartia bispinosa Carl, 1907, is reported for the first time in the Red Sea, where it is found to be an important copepod in the mesozooplankton community structure of the Sharm El-Maya Bay. Female and male are fully redescribed and illustrated of as the mouthparts of this species have never previously been described and figured. Acartia bispinosa was collected in the plankton samples throughout the year and showed two peaks of abundance, a pronounced one in April (4234 individuals m-3), and second smaller peak during November (1784 individuals m-3). The average total length of females varied between 1.32 and 1.53 mm at the end of June and January respectively. For males, the average total length fluctuated between 1.07 and 1.16 mm at end of June and March respectively. Temperature showed an inverse relationship with the body length (P > 0.001) and seemed to be one of the prime factors affecting the body length of both sexes. PMID:25349502

Review of Pennella Oken, 1816 (Copepoda: Pennellidae) with a description of Pennella benzi sp. nov., a parasite of Escolar, Lepidocybium flavobrunneum (Pisces) in the northwest Atlantic Ocean.

PubMed

Hogans, W E

2017-03-17

The genus Pennella Oken, 1816, mesoparasitic copepods from marine fish and mammals, is reviewed with the objective of determining the validity of members of the genus. Details of the external morphological structures of the adult female are presented. Pennella species are differentiated based on a combination of characters: the type of host parasitized, overall length of the parasite, shape, size and configuration of cephalothoracic papillae, segmentation of the first and second antenna, holdfast horn number, shape and configuration, and structure of the abdominal plumes. A new species of Pennella, Pennella benzi sp. nov., is described from the escolar, Lepidocybium flavobrunneum in the northwest Atlantic. Pennella balaenoptera Koren & Danielssen, 1877 is reported from the harbor porpoise (Phocaena phocaena) in the Bay of Fundy, a new locality record. The validity of 44 species is assessed; nine species (P. balaenoptera Koren & Danielssen, 1877, P. benzi sp. nov., P. diodontis Oken, 1816, P. exocoeti (Holten, 1802), P. filosa Linnaeus, 1758, P. hawaiiensis Kazachenko & Kurochkin, 1974, P. instructa Wilson, 1917, P. makaira Hogans, 1988 and P. sagitta Linnaeus, 1758) are considered substantiated and valid; six species (P. elegans Gnanamuthu, 1957, P. longicauda Gnanamuthu, 1957, P. platycephalus Gnanamuthu, 1957, P. remorae Murray, 1856, P. robusta Gnanamuthu, 1957, and P. selaris Kirtisinghe, 1964) exhibit unique characteristics, but are based on descriptions of single specimens, have not been found since the original reports and are considered as species inquirendae; the remaining species are unsubstantiated and invalid based on inadequate or missing original descriptions, or are designated as synonyms of valid species. A key to the valid species of the genus is provided.

Traditional and confocal descriptions of a new genus and two new species of deep water Cerviniinae Sars, 1903 from the Southern Atlantic and the Norwegian Sea: with a discussion on the use of digital media in taxonomy (Copepoda, Harpacticoida, Aegisthidae).

PubMed

Corgosinho, Paulo H C; Kihara, Terue C; Schizas, Nikolaos V; Ostmann, Alexandra; Arbizu, Pedro Martínez; Ivanenko, Viatcheslav N

2018-01-01

Aegisthidae is one of the most abundant and diverse families of harpacticoid copepods living in deep-sea benthos, and the phylogenetic relationships within the family are in state of flux. Females of two new deep-water species of harpacticoid copepods belonging to the Hase gen. n. (Aegisthidae: Cerviniinae) are described. The first taxonomic description of marine copepod species based on the combined use of interference and confocal microscopy for the study of the habitus and dissected appendages is presented here. CLSM (Confocal Laser Scanning Microscopy) is a non-destructive method, comparable in quality to SEM (scanning electron microscopy) at the same magnifications. To observe and reconstruct in detail the habitus and dissected appendages, whole specimens and dissected parts were stained with Congo Red, mounted on slides with glycerine for CLSM and scanned under three visible-light lasers. Hase lagomorphicus gen. et sp. n. and Hase talpamorphicus gen. et sp. n. were collected from the sediments of the Southern Atlantic and the Norwegian Sea, from 2270 m and 5468 m depths, respectively. Hase gen. n. is included within Cerviniinae based on the caudal rami which are relatively divergent. Hase gen. n. is the sister taxon of Cerviniella based on the following synapomorphies: sturdy body, exopodites 1-3 of pereopods 1-3 heavily built, transformed into digging limbs, with strong outer and distal spines/setae, two-segmented endopod on the pereopods 2 and 3, and a reduced pereopod 5. Compared to Cerviniella, Hase gen. n. exhibits a more developed armature on the pereopod 1, which has outer and distal elements transformed into strong and long spines vs. stiff setae on Cerviniella.Hase gen. n. has one or two strong and long spines on the inner margin of the exopodite 3 of pereopod 4 and pereopod 5 is fused to the somite, ornamented with three distal setae. The telson of Hase gen. n. is subquadratic, and the furca is among the shortest yet described for Aegisthidae. The new species differ in a number of diagnostic characters, three of which are: a) the somite bearing pereopods 3 and 4 with latero-distal spiniform processes in H. talpamorphicus gen. et sp. n. but smooth in H. lagomorphicus gen. et sp. n. , b) antenna is armed with three stout spines on the lateral inner margin of the exopod in H. talpamorphicus gen. et sp. n. and two proximal setae in H. lagomorphicus gen. et sp. n. , and c) pereopod 4 exopodite 3 has two long and strong spines on the inner margin in H. lagomorphicus gen. et sp. n. and one spine in H. talpamorphicus gen. et sp. n. The high quality of CLSM images should foster discussion about the use of high quality digital images as type or as part of the type series in zoological studies, especially when studying rare and small macrofaunal and meiofaunal taxa.

Traditional and confocal descriptions of a new genus and two new species of deep water Cerviniinae Sars, 1903 from the Southern Atlantic and the Norwegian Sea: with a discussion on the use of digital media in taxonomy (Copepoda, Harpacticoida, Aegisthidae)

PubMed Central

Corgosinho, Paulo H. C.; Kihara, Terue C.; Schizas, Nikolaos V.; Ostmann, Alexandra; Arbizu, Pedro Martínez; Ivanenko, Viatcheslav N.

2018-01-01

Abstract Aegisthidae is one of the most abundant and diverse families of harpacticoid copepods living in deep-sea benthos, and the phylogenetic relationships within the family are in state of flux. Females of two new deep-water species of harpacticoid copepods belonging to the Hase gen. n. (Aegisthidae: Cerviniinae) are described. The first taxonomic description of marine copepod species based on the combined use of interference and confocal microscopy for the study of the habitus and dissected appendages is presented here. CLSM (Confocal Laser Scanning Microscopy) is a non-destructive method, comparable in quality to SEM (scanning electron microscopy) at the same magnifications. To observe and reconstruct in detail the habitus and dissected appendages, whole specimens and dissected parts were stained with Congo Red, mounted on slides with glycerine for CLSM and scanned under three visible-light lasers. Hase lagomorphicus gen. et sp. n. and Hase talpamorphicus gen. et sp. n. were collected from the sediments of the Southern Atlantic and the Norwegian Sea, from 2270 m and 5468 m depths, respectively. Hase gen. n. is included within Cerviniinae based on the caudal rami which are relatively divergent. Hase gen. n. is the sister taxon of Cerviniella based on the following synapomorphies: sturdy body, exopodites 1–3 of pereopods 1–3 heavily built, transformed into digging limbs, with strong outer and distal spines/setae, two-segmented endopod on the pereopods 2 and 3, and a reduced pereopod 5. Compared to Cerviniella, Hase gen. n. exhibits a more developed armature on the pereopod 1, which has outer and distal elements transformed into strong and long spines vs. stiff setae on Cerviniella.Hase gen. n. has one or two strong and long spines on the inner margin of the exopodite 3 of pereopod 4 and pereopod 5 is fused to the somite, ornamented with three distal setae. The telson of Hase gen. n. is subquadratic, and the furca is among the shortest yet described for Aegisthidae. The new species differ in a number of diagnostic characters, three of which are: a) the somite bearing pereopods 3 and 4 with latero-distal spiniform processes in H. talpamorphicus gen. et sp. n. but smooth in H. lagomorphicus gen. et sp. n., b) antenna is armed with three stout spines on the lateral inner margin of the exopod in H. talpamorphicus gen. et sp. n. and two proximal setae in H. lagomorphicus gen. et sp. n., and c) pereopod 4 exopodite 3 has two long and strong spines on the inner margin in H. lagomorphicus gen. et sp. n. and one spine in H. talpamorphicus gen. et sp. n. The high quality of CLSM images should foster discussion about the use of high quality digital images as type or as part of the type series in zoological studies, especially when studying rare and small macrofaunal and meiofaunal taxa. PMID:29930476

Food-web structure and trophodynamics of mesopelagic-suprabenthic bathyal macrofauna of the Algerian Basin based on stable isotopes of carbon and nitrogen

NASA Astrophysics Data System (ADS)

Fanelli, E.; Cartes, J. E.; Rumolo, P.; Sprovieri, M.

2009-09-01

The trophodynamics of mesopelagic (macrozooplankton/micronekton) and benthic boundary layer (suprabenthos=hyperbenthos) faunas from the Algerian Basin were characterized on a seasonal scale through stable carbon and nitrogen isotopic analyses of a total of 34 species and two broad taxa (Copepoda and Cumacea). This is the first study simultaneously focused on trophodynamics of deep-sea zooplankton and suprabenthos. Samples were collected southeast of Mallorca (Algerian Basin, Western Mediterranean), on the continental slope close to Cabrera Archipelago, at 650-780 m depths, ca. bi-monthly between August 2003 and June 2004. Mean δ 13C values of suprabenthos ranged from -21.1‰ ( Munnopsurus atlanticus) to -16.7‰ ( Cyclaspis longicaudata). Values of δ 15N ranged from 2.8‰ ( Lepechinella manco) to 9.9‰ (larvae of Gnathia sp.). The stable isotope ratios of suprabenthic fauna displayed a continuum of values, confirming a wide spectrum of feeding guilds (from filter feeders/surface deposit feeders to predators). According to the available information on diets for suprabenthic species, the highest annual mean δ 15N values were found for the hematophagous isopod Gnathia sp. parasite on fish (represented by Praniza larvae) and carnivorous amphipods (e.g. Rhachotropis spp., Nicippe tumida) consuming copepods, and the lowest δ 15N values were found for two cumaceans ( Cyclaspis longicaudata and Platysympus typicus) feeding on detritus. Assuming a 15N-enrichment factor of 2.5‰ and deposit feeders as baseline, we found three trophic levels in suprabenthic food webs. δ 13C ranges were particularly wide among deposit feeders (ranging from -21.8% to -17.3‰) and omnivores (from -20.5% to -18.8‰), suggesting exploitation of particulate organic matter (POM) of different characteristics. Our isotopic analyses revealed lower ranges of δ 13C and δ 15N for macrozooplankton/micronekton, compared with suprabenthos. δ 13C values of zooplankton taxa ranged from -21.1�