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Sample records for alewives alosa pseudoharengus

  1. Anadromous alewives, Alosa pseudoharengus, as prey for white perch, Morone americana

    USGS Publications Warehouse

    Moring, J.R.; Mink, L.H.

    2002-01-01

    The reintroduction of anadromous alewives, Alosa pseudoharengus, to their historic habitats in the inland waters of the United States and Canada, has prompted concerns about possible interactions with a popular sport fish, white perch, Morone americana. Both species are now widely distributed in northeastern North America. Diets of white perch in Lake George, Maine, U.S.A., where alewives were absent, were monitored and compared with those of white perch populations that were sympatric with anadromous alewives in two coastal Maine lakes, Biscay Pond and North Pond. In the presence of introduced alewives, the diet of adult white perch became almost exclusively juvenile alewives by late summer in ponds where both species were present. White perch that were sympatric with alewives were more piscivorus than were Lake George white perch, which primarily consumed Cladocera. Not only were alewives the principal prey item in the diet of white perch in Biscay and North ponds, but adult alewives were largely cannibalistic by August. Thus, success of reintroducing anadromous alewives in waters containing white perch may be negatively impacted by predation as well as cannibalism.

  2. Predation by rainbow smelt (Osmerus mordax) on young-of-the-year alewives (Alosa pseudoharengus) in the Great Lakes

    USGS Publications Warehouse

    O'Gorman, Robert

    1974-01-01

    Although predation by rainbow smelt (Osmerus mordax) on young-of-the-year alewives (Alosa pseudoharengus) in the Great Lakes has long been suspected, evidence has been lacking. Young alewives were first noticed in the alimentary tracts of a few large smelt caught in northeastern Lake Ontario in September 1972. A more detailed examination of the stomach contents of smelt taken at various localities in northern Lake Michigan and northern Lake Huron was made during the fall of 1973. Inasmuch as the observations suggest that large smelt commonly prey on young alewives during the fall when the two species occupy the same depth zones, the quantity of young alewives consumed by smelt may represent an important part of the alewife's total mortality during its first year of life.

  3. Intestinal coccidiosis of anadromous and landlocked alewives, Alosa pseudoharengus, caused by Goussia ameliae n. sp. and G. alosii n. sp. (Apicomplexa: Eimeriidae)

    PubMed Central

    Lovy, Jan; Friend, Sarah E.

    2015-01-01

    Anadromous alewives, Alosa pseudoharengus, have experienced significant population level declines caused by factors including habitat destruction. Alewives occur in two different life histories, anadromous and landlocked forms. The landlocked alewife evolved from ancestral anadromous populations, resulting in an exclusively freshwater and phenotypically unique form. The occurrence of parasites in a host is linked to the environment, making alewives an ideal model to compare parasitology within a single species with contrasting life histories. Currently, little information exists on the presence and impacts of parasites in these fish populations; the present study sets out to better understand coccidiosis in the threatened anadromous populations and to understand how coccidian parasites compare in both life history forms. The intestinal coccidian, Goussia ameliae n. sp., was described infecting the pyloric cecum of 76% and 86% of young-of-the-year and adult anadromous alewives, respectively, from the Maurice River, New Jersey, USA. The coccidian was found in landlocked alewife populations with a prevalence of 92% and 34% in YOY and adult fish, respectively. An analysis of the small subunit 18S ribosomal RNA gene of G. ameliae from both life history forms demonstrated that the coccidian had 100% sequence identity, confirming the same parasite species in both forms. Though genetic analysis demonstrated G. ameliae to be identical, some differences were observed in sporulation and morphology of the parasite within the two populations. The sporocysts in anadromous populations were shorter and wider, and sporulation timing differed from that of landlocked fish. These differences may either be attributed to differences in the host type or to the sporulation environment. Lastly, alewives from landlocked populations were frequently co-infected with a second coccidian species in the posterior intestine, which occurred at a lower prevalence. This species, G. alosii n. sp., was

  4. Population characteristics and physical condition of alewives, Alosa pseudoharengus, in a massive die-off in Lake Michigan, 1967

    USGS Publications Warehouse

    Brown, Edward H.

    1968-01-01

    Despite the presence of Saprolegnia and hemorrhages on some fish, alewives in the dieoff appeared robust. Spawning attrition could not have been a major cause of the dieoff because many immature yearlings died and 80 percent of the dead adults were unspawned. The presence of rapidly digestible zooplankton in the stomachs of dead alewives indicated that many fish were feeding just before death. About 20 percent of the alewives in the selected samples of fish from the dieoff were infected by Saprolegnia; twice as many females were infected as males. The fungus was randomly distributed among the size groups. Hemorrhages may have been a symptom or physiological response to the cause of the dieoff because they affected a much higher percentage of the dying alewives (47 percent) than did fungus. Occurrence of the hemorrhages did not differ significantly between the sexes or among the size groups.

  5. Variation in Lake Michigan alewife (Alosa pseudoharengus) thiaminase and fatty acids composition

    USGS Publications Warehouse

    Honeyfield, D.C.; Tillitt, D.E.; Fitzsimons, J.D.; Brown, S.B.

    2010-01-01

    Thiaminase activity of alewife (Alosa pseudoharengus) is variable across Lake Michigan, yet factors that contribute to the variability in alewife thiaminase activity are unknown. The fatty acid content of Lake Michigan alewife has not been previously reported. Analysis of 53 Lake Michigan alewives found a positive correlation between thiaminase activity and the following fatty acid: C22:ln9, sum of omega-6 fatty acids (Sw6), and sum of the polyunsaturated fatty acids. Thiaminase activity was negatively correlated with C15:0, C16:0, C17:0, C18:0, C20:0, C22:0, C24:0, C18:ln9t, C20:3n3, C22:2, and the sum of all saturated fatty acids (SAFA). Multi-variant regression analysis resulted in three variables (C18:ln9t, Sw6, SAFA) that explained 71% (R2=0.71, P<0.0001) of the variation in thiaminase activity. Because the fatty acid content of an organism is related is food source, diet may be an important factor modulating alewife thiaminase activity. These data suggest there is an association between fatty acids and thiaminase activity in Lake Michigan alewife.

  6. Genetic Divergence between Freshwater and Marine Morphs of Alewife (Alosa pseudoharengus): A ‘Next-Generation’ Sequencing Analysis

    PubMed Central

    Czesny, Sergiusz; Epifanio, John; Michalak, Pawel

    2012-01-01

    Alewife Alosa pseudoharengus, a small clupeid fish native to Atlantic Ocean, has recently (∼150 years ago) invaded the North American Great Lakes and despite challenges of freshwater environment its populations exploded and disrupted local food web structures. This range expansion has been accompanied by dramatic changes at all levels of organization. Growth rates, size at maturation, or fecundity are only a few of the most distinct morphological and life history traits that contrast the two alewife morphs. A question arises to what extent these rapidly evolving differences between marine and freshwater varieties result from regulatory (including phenotypic plasticity) or structural mutations. To gain insights into expression changes and sequence divergence between marine and freshwater alewives, we sequenced transcriptomes of individuals from Lake Michigan and Atlantic Ocean. Population specific single nucleotide polymorphisms were rare but interestingly occurred in sequences of genes that also tended to show large differences in expression. Our results show that the striking phenotypic divergence between anadromous and lake alewives can be attributed to massive regulatory modifications rather than coding changes. PMID:22438868

  7. Genetic divergence between freshwater and marine morphs of alewife (Alosa pseudoharengus): a 'next-generation' sequencing analysis.

    PubMed

    Czesny, Sergiusz; Epifanio, John; Michalak, Pawel

    2012-01-01

    Alewife Alosa pseudoharengus, a small clupeid fish native to Atlantic Ocean, has recently (∼150 years ago) invaded the North American Great Lakes and despite challenges of freshwater environment its populations exploded and disrupted local food web structures. This range expansion has been accompanied by dramatic changes at all levels of organization. Growth rates, size at maturation, or fecundity are only a few of the most distinct morphological and life history traits that contrast the two alewife morphs. A question arises to what extent these rapidly evolving differences between marine and freshwater varieties result from regulatory (including phenotypic plasticity) or structural mutations. To gain insights into expression changes and sequence divergence between marine and freshwater alewives, we sequenced transcriptomes of individuals from Lake Michigan and Atlantic Ocean. Population specific single nucleotide polymorphisms were rare but interestingly occurred in sequences of genes that also tended to show large differences in expression. Our results show that the striking phenotypic divergence between anadromous and lake alewives can be attributed to massive regulatory modifications rather than coding changes.

  8. Catches of larval rainbow smelt (Osmerus mordax) and alewife (Alosa pseudoharengus) in plankton nets of different mesh sizes

    USGS Publications Warehouse

    O'Gorman, Robert

    1984-01-01

    Four 0.5-m plankton nets (one each of 0.355-, 0.450-, 0.560-, and 0.750-mm mesh) were used to collect larvae of the alewife (Alosa pseudoharengus) and rainbow smelt (Osmerus mordax) in northwestern Lake Huron and the St. Marys River. The number of larvae collected varied inversely with mesh size and the average length of larvae varied directly with mesh size. Numbers of each species caught in 0.355- and 0.450-mm mesh nets were significantly greater (P < 0.01) than the numbers caught in 0.560- and 0.750-mm mesh nets. Numbers of alewives caught were significantly greater (P < 0.01) in the 0.355- than in the 0.450-mm mesh, but numbers of rainbow smelt caught in the two meshes were about equal. Between the two larger-mesh nets, numbers of each species caught did not differ significantly. Nets with mesh larger than 0.355 mm were less effective at catching recently hatched larvae, and this reduced effectiveness accounted wholly for the smaller numbers caught in the 0.450-mm mesh net. Smaller numbers were caught in the 0.560- and 0.750-mm mesh nets not only because they caught fewer recently hatched larvae but also because they failed to retain older, larger larvae. Information on the effect of mesh size and towing speed on catches of larvae is important for making accurate estimates of larval densities.

  9. Recent changes in Lake Michigan's fish community and their probable causes, with emphasis on the role of the alewife (Alosa pseudoharengus)

    USGS Publications Warehouse

    Eck, Gary W.; Wells, LaRue

    1987-01-01

    Deepwater ciscoes (Coregonus spp.) or "chubs" of Lake Michigan far surpassed those of Lake Huron in yield, population density, and resilience following severe depletion in the 1960s and 1970s, when the bloater (C. hoyi) composed more than 90% of the stocks. The population decline of bloaters in recent decades was mainly attributed to exploitation, to the depression of chub recruitment (e.g. from inferred predation on early life stages) by nonendemic alewives (Alosa pseudoharengus) and rainbow smelt (Osmerus mordax), and to complications arising from extreme female predominance that was best documented for Lake Michigan. The various interactions between bloaters and the nonendemic species, which were intensified after the loss of large predators to sea lamprey (Petromyzon marinus), would help to explain why a stock–recruitment relation was not shown for the Lake Michigan bloater. We hypothesize that reproductive inefficiency caused by a shift to strong female predominance in the bloater depresses recruitment and thus helps to regulate abundance. However, the low resilience that sex imbalance seems to impart makes the stock unstable when exploited. It should therefore be exploited conservatively during such periods. Also, the sex ratio and its direction of change appear to be important qualifiers when surplus production is estimated from stock size.

  10. Effects of abundance and water temperature on recruitment and growth of alewife (Alosa pseudoharengus) near South Bay, Lake Huron, 1954-82

    USGS Publications Warehouse

    Henderson, Bryan A.; Brown, Edward H.

    1985-01-01

    Analysis of catches in pound nets provided indices of population size (ages 2–6) and of recruitment (ages 4–6) for alewives (Alosa pseudoharengus) spawning in South Bay (1954–82). Four hypotheses concerning the effects of stock size and water temperature on growth and recruitment were tested statistically. The number of recruits per spawner was not a function of parental stock size, but was dependent on surface-water temperatures in June and July. Although the size of both males and females at age 3 yr was positively related to surface-water temperatures in the three preceding summers, growth rates were only a function of water temperatures during the second year of growth (age 1). However, growth rates during the first, second, and third years of growth were all related to year-class strength. Thus, population abundance, through recruitment, was determined by an abiotic factor (water temperature), but growth was mostly affected by intraspecific competition for, presumably, food.

  11. Beta-thymosin gene polymorphism associated with freshwater invasiveness of alewife (Alosa pseudoharengus)

    USGS Publications Warehouse

    Michalak, Katarzyna; Czesny, Sergiusz J.; Epifanio, John; Snyder, Randal J.; Schultz, Eric T.; Velotta, Jonathan P.; McCormick, Stephen D.; Brown, Bonnie L.; Santopietro, Graciela; Michalak, Pawel

    2014-01-01

    Predicting the success of a species’ colonization into a novel environment is routinely considered to be predicated on niche-space similarity and vacancy, as well as propagule pressure. The role genomic variation plays in colonization success (and the interaction with environment) may be suggested, but has not rigorously been documented. To test an hypothesis that previously observed ecotype-specific polymorphisms between anadromous and landlocked alewife (Alosa pseudoharengus) populations are an adaptive response to osmoregulatory challenges rather than a result of allele sampling at founding, we examined multiple anadromous and landlocked (colonized) populations for their allelic profiles at a conserved region (3’-UTR end) of a β-thymosin gene whose protein product plays a central role in the organization of cytoskeleton. The putatively ancestral β-thymosin allele was prevalent in anadromous populations, whereas a newly derived allele was overrepresented in landlocked populations; a third allele was exclusive to the anadromous populations. We also conducted a complementary set of salinity exposure experiments to test osmoregulatory performance of the alewife ecotypes in contrasting saline environments. The pattern of variation and results from these challenges indicate a strong association of β-thymosin with colonization success and a transition for species with an anadromous life-history to one with only a freshwater component.

  12. Distribution of alewives in southeastern Lake Ontario in autumn and winter: a clue to winter mortalities

    USGS Publications Warehouse

    Bergstedt, Roger A.; O'Gorman, Robert

    1989-01-01

    Alewives Alosa pseudoharengus in the Great Lakes are thought to avoid extreme cold in winter by moving to deep water where the temperature is usually highest because of inverse thermal stratification. Information collected in Lake Ontario during autumn and winter 1981–1984 with an echo sounder and bottom and midwater trawls indicated that many alewives remained at depths above 110 m, regardless of water temperature. Alewives in the Great Lakes that did not descend to greater depths would be exposed to potentially lethal temperatures during cold winters.inters.

  13. Long-term changes of the Lake Michigan fish community following the reduction of exotic alewife (Alosa pseudoharengus)

    USGS Publications Warehouse

    Bunnell, D.B.; Madenjian, C.P.; Claramunt, R.M.

    2006-01-01

    We used our long-term annual bottom trawl survey (1973–2004) in Lake Michigan to reveal the response of the native fish community to the biological control of a dominant exotic fish, alewife (Alosa pseudoharengus), as well as to changes in total phosphorus and salmonine biomass. Through nonmetric multidimensional scaling, we documented a 1970s community largely dominated by alewife, and then a shift to a community dominated by several native species during the 1980s through 1990s, when alewife remained at relatively low levels. We argue that the recovery of burbot (Lota lota), deepwater sculpin (Myoxocephalus thompsonii), and yellow perch (Perca flavescens) was partially or fully aided by the alewife reduction. We argue that changes in phosphorus or salmonines were not directly related to abundance increases of native species. An additional community shift occurred during 1999–2004, which coincided with a reduction in species richness and total fish biomass in our trawl. The mechanisms underlying this latest shift may be related to reductions in nutrients, but further research is required. The restoration of the native fish community has been incomplete, however, as emerald shiner (Notropis atherinioides), cisco (Coregonus artedii), and lake trout (Salvelinus namaycush) have yet to demonstrate recovery.

  14. Consumer interaction strength may limit the diversifying effect of intraspecific competition: a test in alewife (Alosa pseudoharengus).

    PubMed

    Jones, Andrew W; Post, David M

    2013-06-01

    Intraspecific competition is considered a principal driver of dietary variation, but empirical studies provide mixed support for this mechanism. Here we link comparative and experimental work testing the effects of competition and resource availability on the dietary variation of the alewife (Alosa pseudoharengus). The alewife, a consumer with extreme effects on its resources, was specifically utilized to additionally test the idea that strong interactions between a consumer and its resources can diminish the diversifying effect of competition. First, we compared the short- and long-term diet measures of wild populations across a wide range of densities. Second, in a pair of large-scale field mesocosm experiments, we explored the influence of competition and interaction strength on alewife dietary variation. Results from a whole-lake comparison and field experiments indicated that increasing competition was negatively correlated with population dietary variation. Further, altering the strength of the interaction between the alewife and its prey via prey supplementation eliminated this negative relationship. Collectively, our results suggest that competitive interactions may not drive dietary diversification in the alewife and, potentially, in other highly effective consumers. Our results also indicate that further consideration of the strength of species interactions (and the consumer traits that underlie them) would improve our understanding of the link between intraspecific competition and variation.

  15. Food of the alewife (Alosa pseudoharengus) in Lake Ontario before and after the establishment of Bythotrephes cederstroemi

    USGS Publications Warehouse

    Mills, Edward L.; O'Gorman, Robert; DeGisi, Joe; Heberger, Roy; House, Robert A.

    1992-01-01

    Diets and length–weight relationships of Lake Ontario alewife (Alosa pseudoharengus) in 1972 differed from those in 1988; the large cladoceran Bythotrephes cederstroemi colonized the lake during the mid-1980's. Micro-crustacean zooplankton were the dominant prey of alewife during April–October in 1972 and 1988. Although Bythotrephes was not found in 1988 net samples, it replaced other zooplankters in the alewife's diet. Typically, tailspines were the only part ofBythotrephes in alewife stomachs; their frequency was high in April–May, diminished rapidly in summer and was very low by fall. In spring 1988, alewife  were in better condition than in spring 1972 and this may have been due to larger fish feeding more heavily onBythotrephes. Variation in diet among widely separated sampling sites was due to differences in alewife abundance, stability of thermal structure, progress of zooplankton community development and distance to the mouth of the Niagara River (through which Bythotrephesprobably enter the lake in summer and fall). In the Great Lakes, inter- and intralake differences in diet clearly exist, and these must be incorporated into models of alewife planktivory to gain an accurate understanding of energy flow between trophic levels.

  16. Effects of temperature on electrolyte balance and osmoregulation of the alewife (Alosa pseudoharengus) in fresh and sea water

    USGS Publications Warehouse

    Stanley, Jon G.; Colby, Peter J.

    1971-01-01

    In the laboratory, alewife mortalities caused by increasing or decreasing temperatures were about equal in fresh water and sea water. These findings suggest that salinity does not modify the capacity of alewives to tolerate acute temperature stress.

  17. Discrepancies between ages determined from scales and otoliths for alewives from the Great Lakes

    USGS Publications Warehouse

    O'Gorman, Robert; Barwick, D. Hugh; Bowen, Charles A.; Summerfelt, R.D.; Hall, G.E.

    1987-01-01

    Discrepancies between ages determined from otoliths and those determined from scales were common and, sometimes, quite large in alewives Alosa pseudoharengus collected in fall 1983 from Lakes Ontario, Huron, and Michigan. Among fish with 'otolith ages' of 4 or more, the percentages having identical 'scale ages' were 1% in Lake Ontario, 35% in Lake Huron, and 56% in Lake Michigan. Among alewives with different otolith and scale ages, the percentages with discrepancies of 3 years or more were 51% in Lake Ontario, 23% in Lake Huron, and 6% in Lake Michigan. Among the three populations, variation in the magnitude of age disagreements were perhaps due to the different mortality rates in each lake, whereas variation in the frequency of disagreements appeared to be due to different ratios of food to fish in each lake. Previously reported age compositions and rates of mortality and production for Great Lakes alewives derived from scales have probably been inaccurate to various degrees.

  18. Recruitment variability of alewives in Lake Michigan

    USGS Publications Warehouse

    Madenjian, C.P.; Hook, T.O.; Rutherford, E.S.; Mason, D.M.; Croley, T.E.; Szalai, E.B.; Bence, J.R.

    2005-01-01

    We used a long-term series of observations on alewife Alosa pseudoharengus abundance that was based on fall bottom-trawl catches to assess the importance of various abiotic and biotic factors on alewife recruitment in Lake Michigan during 1962–2002. We first fit a basic Ricker spawner–recruit model to the lakewide biomass estimates of age-3 recruits and the corresponding spawning stock size; we then fit models for all possible combinations of the following four external variables added to the basic model: an index of salmonine predation on an alewife year-class, an index for the spring–summer water temperatures experienced by alewives during their first year in the lake, an index of the severity of the first winter experienced by alewives in the lake, and an index of lake productivity during an alewife year-class's second year in the lake. Based on an information criterion, the best model for alewife recruitment included indices of salmonine predation and spring–summer water temperatures as external variables. Our analysis corroborated the contention that a decline in alewife abundance during the 1970s and early 1980s in Lake Michigan was driven by salmonine predation. Furthermore, our findings indicated that the extraordinarily warm water temperatures during the spring and summer of 1998 probably led to a moderately high recruitment of age-3 alewives in 2001, despite abundant salmonines.

  19. Annual variation in habitat-specific recruitment success: Implications from an individual-based model of Lake Michigan alewife (Alosa pseudoharengus)

    USGS Publications Warehouse

    Hook, T.O.; Rutherford, E.S.; Croley, T.E.; Mason, D.M.; Madenjian, C.P.

    2008-01-01

    The identification of important spawning and nursery habitats for fish stocks can aid fisheries management, but is complicated by various factors, including annual variation in recruitment success. The alewife (Alosa pseudoharengus) is an ecologically important species in Lake Michigan that utilizes a variety of habitats for spawning and early life growth. While productive, warm tributary mouths (connected to Lake Michigan) may contribute disproportionately more recruits (relative to their habitat volume) to the adult alewife population than cooler, less productive nearshore habitats, the extent of interannual variation in the relative contributions of recruits from these two habitat types remains unknown. We used an individual-based bioenergetics simulation model and input data on daily temperatures to estimate alewife recruitment to the adult population by these different habitat types. Simulations suggest that nearshore lake habitats typically produce the vast majority of young alewife recruits. However, tributary habitats may contribute the majority of alewife recruits during years of low recruitment. We suggest that high interannual variation in the relative importance of habitats for recruitment is a common phenomenon, which should be considered when developing habitat management plans for fish populations. ?? 2008 NRC.

  20. Planktivory by alewife (Alosa pseudoharengus) and rainbow smelt (Osmerus mordax) on microcrustacean zooplankton and dreissenid (Bivalvia: Dreissenidae) veligers in southern Lake Ontario

    USGS Publications Warehouse

    Mills, Edward L.; O'Gorman, Robert; Roseman, Edward F.; Adams, Connie; Owens, Randall W.

    1995-01-01

    The objective of this study was to describe the diet of young-of-the-year and adult alewife (Alosa pseudoharengus) and rainbow smelt (Osmerus mordax) in nearshore waters coincident with the colonization of Lake Ontario by Dreissena. Laboratory experiments and field observations indicated that alewife and rainbow smelt consumed dreissenid veligers and that the veligers remained intact and identifiable in the digestive tract for several hours. Dreissenid larvae were found in field-caught alewife and rainbow smelt in August 1992, even though veliger densities were low (<0.1/L). Zooplankton dominated the diet of all fish and veliger larvae were <0.1% of the biomass of prey eaten by these fish. Density of veligers and the distribution of settled dreissenids declined from west to east along the south shore of Lake Ontario. Based on veliger consumption rates we measured and the abundance of veligers and planktivores, we conclude that planktivory by alewife and smelt in the nearshore waters of Lake Ontario did not substantially reduce the number of veligers during 1991–1993. However, our results indicate that if the density of veligers in Lake Ontario decreases, and if planktivores remain abundant, planktivory on veliger populations could be significant.

  1. Reproduction and early-life accommodations of landlocked alewives to a southern range extension

    USGS Publications Warehouse

    Nigro, A.A.; Ney, John J.

    1982-01-01

    Reproduction and first-year growth and food habits of landlocked alewives Alosa pseudoharengus in Claytor Lake, Virginia were examined and compared to descriptions for populations in the species' established New England-Great Lakes range. Alewives in mesothermal (2–27 C) Claytor Lake are shorter-lived (3 years) but grow faster, mature earlier (age 1), and have higher relative and absolute fecundities than have been reported for populations in colder northern waters. The 1979 spawning period extended from early May to early August, beginning at least 1 month earlier and lasting 4–9 weeks longer than in northern lakes. Changes in ovary condition during the spawning period suggest that alewives may be fractional spawners. Evidence of spawning was found in littoral areas throughout the lower 15 km of the reservoir. Growth in length of age-0 Claytor Lake alewives was linear through September and terminated in late autumn. Total first-year growth was reduced in 1979 (maximum of 130 mm total length, TL) from previous years (average of 160 mm TL), although it was substantially greater than recorded in the Great Lakes and the northeastern United States. The longer growing season, rather than accelerated in-season growth, appears to account for larger size achieved in Claytor Lake. High annual growth limits predation by Claytor Lake game fish on early spawned age-0 alewives by late summer. As elsewhere, larval and juvenile alewives (6–70 mm TL) fed primarily on copepods and cladocerans. Age-0 alewives longer than 35 mm TL demonstrated positive size-selection for cyclopoid copepods comparable to that shown by adults. Our findings suggest that self-sustaining alewife populations can be established in many inland waters but raise concerns regarding their forage value and community impacts.

  2. Relaxed selection causes microevolution of seawater osmoregulation and gene expression in landlocked Alewives

    USGS Publications Warehouse

    Velotta, Jonathan P.; McCormick, Stephen D.; O'Neill, Rachel J.; Schultz, Eric T.

    2014-01-01

    Ecological transitions from marine to freshwater environments have been important in the creation of diversity among fishes. Evolutionary changes associated with these transitions likely involve modifications of osmoregulatory function. In particular, relaxed selection on hypo-osmoregulation should strongly affect animals that transition into novel freshwater environments. We used populations of the Alewife (Alosa pseudoharengus) to study evolutionary shifts in hypo-osmoregulatory capacity and ion regulation associated with freshwater transitions. Alewives are ancestrally anadromous, but multiple populations in Connecticut have been independently restricted to freshwater lakes; these landlocked populations complete their entire life cycle in freshwater. Juvenile landlocked and anadromous Alewives were exposed to three salinities (1, 20 and 30 ppt) in small enclosures within the lake. We detected strong differentiation between life history forms: landlocked Alewives exhibited reduced seawater tolerance and hypo-osmoregulatory performance compared to anadromous Alewives. Furthermore, gill Na+/K+-ATPase activity and transcription of genes for seawater osmoregulation (NKCC—Na+/K+/2Cl− cotransporter and CFTR—cystic fibrosis transmembrane conductance regulator) exhibited reduced responsiveness to seawater challenge. Our study demonstrates that adaptations of marine-derived species to completely freshwater life cycles involve partial loss of seawater osmoregulatory performance mediated through changes to ion regulation in the gill.

  3. Effect of stock size, climate, predation, and trophic status on recruitment of alewives in Lake Ontario, 1978-2000

    USGS Publications Warehouse

    O'Gorman, Robert; Lantry, Brian F.; Schneider, Clifford P.

    2004-01-01

    The population of alewives Alosa pseudoharengus in Lake Ontario is of great concern to fishery managers because alewives are the principal prey of introduced salmonines and because alewives negatively influence many endemic fishes. We used spring bottom trawl catches of alewives to investigate the roles of stock size, climate, predation, and lake trophic status on recruitment of alewives to age 2 in Lake Ontario during 1978–2000. Climate was indexed from the temperature of water entering a south-shore municipal treatment plant, lake trophic status was indexed by the mean concentration of total phosphorus (TP) in surface water in spring, and predation was indexed by the product of the number of salmonines stocked and relative, first-year survival of Chinook salmonOncorhynchus tshawytscha. A Ricker-type parent–progeny model suggested that peak production of age-1 alewives could occur over a broad range of spawning stock sizes, and the fit of the model was improved most by the addition of terms for spring water temperature and winter duration. With the addition of the two climate terms, the Ricker model indicated that when water was relatively warm in spring and the winter was relatively short, peak potential production of young was nine times higher than when water temperature and winters were average, and 73 times higher than when water was cold in spring and winters were long. Relative survival from age 1 to recruitment at age 2 was best described by a multiple linear regression with terms for adult abundance, TP, and predation. Mean recruitment of age-2 fish in the 1978–1998 year-classes predicted by using the two models in sequence was only about 20% greater than the observed mean recruitment. Model estimates fit the measured data exceptionally well for all but the largest four year-classes, which suggests that the models will facilitate improvement in estimates of trophic transfer due to alewives.

  4. The bioenergetic consequences of invasive-induced food web disruption to Lake Ontario alewives

    USGS Publications Warehouse

    Stewart, Thomas J.; O'Gorman, Robert; Sprules, W. Gary; Lantry, B.F.

    2010-01-01

    Alewives Alosa pseudoharengus are the dominant prey fish in Lake Ontario, and their response to ecological change can alter the structure and function of the Lake Ontario food web. Using stochastic population-based bioenergetic models of Lake Ontario alewives for 1987–1991 and 2001–2005, we evaluated changes to alewife production, consumption, and associated bioenergetic ratios after invasive-induced food web disruption. After the disruption, mean biomass of alewives declined from 28.0 to 14.6 g/m2, production declined from 40.8 to 13.6 g·m−2·year−1, and consumption declined from 342.1 to 137.2 g·m−2·year−1, but bootstrapping of error sources suggested that the changes were not statistically significant. Population-based bioenergetic ratios of production to biomass (P/B ratio), total consumption to biomass (Q/B ratio), and production efficiency did not change. Pathways of energy flow measured as prey-group-specific Q/B ratios changed significantly between the two time periods for invasive predatory cladocerans (from 0.6 to 1.3), Mysis diluviana (from 0.4 to 2.5), and other prey (from 0.8 to 0.1), but the observed decline in the zooplankton Q/B ratio (from 10.6 to 5.5) was not significant. Gross production efficiency did not change; values ranged from 8% to 15%. Age-group mean gross conversion efficiency (GCE) declined with age; GCE ranged from 7.5% to 11.0% for yearlings, was approximately 5% for age-2 alewives, and was less than 2% for age-3 and older alewives. The GCE increased significantly between the time periods for yearling alewives. Our analyses support the hypothesis that after 2003, alewives could not sustain their growth while feeding on zooplankton closer to shore. Modeling of observed spatial variation in diet and alternative occupied temperatures demonstrates the potential for reducing consumption by alewives. Our results suggest that Lake Ontario alewives can exploit spatial heterogeneity in resource patches and thermal habitat to

  5. Dynamics of alewives in Lake Ontario following a mass mortality

    USGS Publications Warehouse

    O'Gorman, Robert; Schneider, Clifford P.

    1986-01-01

    The U.S. Fish and Wildlife Service and the New York Department of Environmental Conservation assessed the population of alewives Alosa pseudoharengus in U.S. waters of Lake Ontario during 1976–1982 with bottom trawls. Alewives were abundant in 1976 but a die-off greatly reduced their numbers during the winter of 1976–1977. The population quickly recovered, however, adult abundance increasing nearly sevenfold during 1978–1981. In spring 1981 the bottom population in southern Lake Ontario was estimated to be 5.25 × 109 fish weighing 128,500 t. Estimated average alewife biomass per hectare during 1978–1982 far exceeded the estimates for either Lake Michigan during 1967–1982 or western Lake Huron during 1973–1982. Recruitment of age-II fish to the population was affected by abundance of adults in two ways: (1) the number of yearlings produced was directly related to adult abundance at low population levels but inversely related at high population levels; and (2) survival of yearlings to age II was inversely related to adult abundance. Growth in 1977 was exceptional, leaving a wide, unmistakable band on scales of the previously slow-growing adults. This wide growth zone served as a marker to identify survivors of the 1976–1977 die-off and to show that each year after 1978 a successively larger proportion of survivors was failing to grow in length or to form an annulus (54% in 1979, 96% in 1980, and 100% in 1981). There was no marker on scales of alewives recruited after the die-off, but the apparent age composition of our catches strongly suggested that most of them also failed to grow in 1981.

  6. Shifts in depth distributions of alewives, rainbow smelt, and age-2 lake trout in southern Lake Ontario following establishment of Dreissenids

    USGS Publications Warehouse

    O'Gorman, Robert; Elrod, Joseph H.; Owens, Randall W.; Schneider, Clifford P.; Eckert, Thomas H.; Lantry, Brian F.

    2000-01-01

    In the mid-1990s, biologists conducting assessments of fish stocks in Lake Ontario reported finding alewives Alosa pseudoharengus, rainbow smelt Osmerus mordax, and juvenile lake trout Salvelinus namaycush at greater depths than in the mid-1980s. To determine if depth distributions shifted coincident with the early 1990s colonization of Lake Ontario by exotic Dreissena mussels, we calculated mean depth of capture for each of the three species during trawl surveys conducted annually during 1978–1997 and examined the means for significant deviations from established patterns. We found that mean capture depth of alewives, rainbow smelt, and age-2 lake trout shifted deeper during the build up of the dreissenid population in Lake Ontario but that timing of the shift varied among seasons and species. Depth shifts occurred first for rainbow smelt and age-2 lake trout in June 1991. In 1992, alewives shifted deeper in June followed by age-2 lake trout in July–August. Finally, in 1993 and 1994, the distribution of lake trout and alewives shifted in April–May. Reasons why the three fishes moved to deeper water are not clear, but changes in distribution were not linked to temperature. Mean temperature of capture after the depth shift was significantly lower than before the depth shift except for alewives in April–May. Movement of alewives, rainbow smelt, and age-2 lake trout to colder, deeper water has the potential to alter growth and reproduction schedules by exposing the fish to different temperature regimes and to alter the food chain, increasing predation on Mysis relicta in deep water and decreasing alewife predation on lake trout fry over nearshore spawning grounds in spring.

  7. Branchial ionocyte organization and ion-transport protein expression in juvenile alewives acclimated to freshwater or seawater

    USGS Publications Warehouse

    Christensen, A.K.; Hiroi, J.; Schultz, E.T.; McCormick, S.D.

    2012-01-01

    The alewife (Alosa pseudoharengus) is a clupeid that undergoes larval and juvenile development in freshwater preceding marine habitation. The purpose of this study was to investigate osmoregulatory mechanisms in alewives that permit homeostasis in different salinities. To this end, we measured physiological, branchial biochemical and cellular responses in juvenile alewives acclimated to freshwater (0.5p.p.t.) or seawater (35.0p.p.t.). Plasma chloride concentration was higher in seawater-acclimated than freshwater-acclimated individuals (141mmoll -1 vs 134mmoll -1), but the hematocrit remained unchanged. In seawateracclimated individuals, branchial Na +/K +-ATPase (NKA) activity was higher by 75%. Western blot analysis indicated that the abundance of the NKA subunit and a Na+/K+/2Cl- cotransporter (NKCC1) were greater in seawater-acclimated individuals by 40% and 200%, respectively. NKA and NKCC1 were localized on the basolateral surface and tubular network of ionocytes in both acclimation groups. Immunohistochemical labeling for the cystic fibrosis transmembrane conductance regulator (CFTR) was restricted to the apical crypt of ionocytes in seawater-acclimated individuals, whereas sodium/hydrogen exchanger 3 (NHE3) labeling was present on the apical surface of ionocytes in both acclimation groups. Ionocytes were concentrated on the trailing edge of the gill filament, evenly distributed along the proximal 75% of the filamental axis and reduced distally. Ionocyte size and number on the gill filament were not affected by salinity; however, the number of lamellar ionocytes was significantly lower in seawater-acclimated fish. Confocal z-series reconstructions revealed that mature ionocytes in seawater-acclimated alewives occurred in multicellular complexes. These complexes might reduce paracellular Na + resistance, hence facilitating Na+ extrusion in hypo-osmoregulating juvenile alewives after seaward migration. ?? 2012. Published by The Company of Biologists Ltd.

  8. Changes in consumption by alewives and lake whitefish after dreissenid mussel invasions in Lakes Michigan and Huron

    USGS Publications Warehouse

    Pothoven, S.A.; Madenjian, C.P.

    2008-01-01

    Growth of alewives Alosa pseudoharengus and lake whitefish Coregonus clupeaformis has declined since the arrival and spread of dreissenid mussels in Lakes Michigan and Huron. Alewives are the main forage for the salmonids in Lake Michigan, and lake whitefish are the most important commercial species in both lakes. Bioenergetics modeling was used to determine consumption by the average individual fish before and after the dreissenid invasion and to provide insight into the invasion's effects on fish growth and food web dynamics. Alewives feed on both Zooplankton and benthic macroinvertebrates, and lake whitefish are benthivores. Annual consumption of zooplankton by an average alewife in Lake Michigan was 37% lower and consumption of benthic macroinvertebrates (amphipods Diporeia spp., opossum shrimp Mysis relicta, and Chironomidae) was 19% lower during the postinvasion period (1995-2005) than during the preinvasion period (1983-1994). Reduced consumption by alewives corresponded with reduced alewife growth. In Lakes Michigan and Huron, consumption of nonmollusk macroinvertebrates (Diporeia spp., opossum shrimp, Chironomidae) by the average lake whitefish was 46-96% lower and consumption of mollusks (mainly dreissenids and gastropods) was 2-5 times greater during the postinvasion period than during the preinvasion period. Even though total food consumption by lake whitefish did not differ between the two periods in Lake Huron or the Southern Management Unit in Lake Michigan, postinvasion weight at age was at least 38% lower than preinvasion weight at age. Under the current postinvasion diet regime, consumption by lake whitefish would have to increase by up to 122% to achieve preinvasion growth rates. ?? Copyright by the American Fisheries Society 2008.

  9. Food of alewives, yellow perch, spottail shiners, trout-perch, and slimy and fourhorn sculpins in southeastern Lake Michigan

    USGS Publications Warehouse

    Wells, LaRue

    1980-01-01

    Stomachs of 1,064 alewives (Alosa pseudoharengus), 1,103 yellow perch (Perca flavescens), 246 spottail shiners (Notropis hudsonius), 288 trout-perch (Percopsis omiscomaycus), 454 slimy sculpins (Cottus cognatus), and 562 fourhorn sculpins (Myoxocephalus quadricornis) from Lake Michigan were examined for food contents. Fish were sampled primarily from March to November and nearly all were caught at the bottom in the southeastern part of the lake near Saugatuck, Michigan. Depths of capture (m) were: alewives, 5 to 110; yellow perch, 5 to 26; spottail shiners, 5 to 31; trout-perch, 9 to 46; slimy sculpins, 31 to 91; and fourhorn sculpins, 73 to 110. Alewives, particularly those less than 140 mm long, fed chiefly on zooplankton; Pontoporeia usually constituted most of the rest of the food, although Mysis and immature midges were occasionally eaten in considerable quantity. Yellow perch ate primarily Pontoporeia, fish eggs, Mysis, and crayfish; Pontoporeia was consumed most heavily by perch less than 250 mm long and those in relatively deep water, fish (mainly slimy sculpins) by those 200 mm long or longer, Mysis by those in deep water, and crayfish by those on rocky bottom. Spottail shiners fed most commonly on immature midges, Pontoporeia, zooplankton, fingernail clams, and (in July only) fish eggs; immature midges were eaten mainly by shiners in shallow water; and Pontoporeia by those in deeper areas. The diet of trout-perch was strongly dominated by Pontoporeia and immature midges. Slimy sculpins ate Pontoporeia almost exclusively. Fourhorn sculpins fed almost entirely on Mysis and Pontoporeia; Pontoporeia was particularly important in the diet of the larger fish.

  10. Age and growth of alewives in the changing pelagia of Lake Ontario, 1978-1992

    USGS Publications Warehouse

    O'Gorman, Robert; Johannsson, Ora E.; Schneider, Clifford P.

    1997-01-01

    We documented the age and growth of alewives Alosa pseudoharenqus in Lake Ontario during 1978-1992 and determined if growth was affected by intraspecific competition for epilimnetic zooplankton, lake temperature, or demand of salmonine piscivores for prey. Ages of juvenile alewives were determined from scales during 1978-1983, and ages of juvenile and adult alewives were determined from otoliths during 1984-1992. Indices of abundance for alewives were calculated from spring bottom trawl catches in 1978-1992; zooplankton density and epilimnetic temperature were monitored at two stations during 1981-1991; and salmonine demand each year during 1978-1992 was calculated with a simulation model. Although we encountered 11-year-old alewives, few fish lived longer than 7 years, and most fish in the population were younger than 6 years. Mean sizes at ages 1, 2, and 3 in spring averaged 93 mm (5.1 g), 133 mm (17 g), and 149 mm (22 g), but from age 3 to age 8, mean size increased by only 5-7 mm and 2-3 g per year. Female alewives lived longer than male alewives and were always longer than male alewives at age 4 and older. Epilimnetic temperatures were suitable for rapid growth of juvenile alewives each year. Lake temperature had the potential to affect growth of adults but adult growth was not correlated with temperature suitability indices perhaps because temperature regimes differed among lake regions and alewives were mobile. Growth of alewives was not correlated with salmonine demand for prey. Competition for zooplankton among the two youngest alewife cohorts affected growth of age-1 alewives. Zooplankton density declined sharply in 1986, and should it decline again, growth of age-1 alewives will slow, unless numbers of age-0 alewives fall. Whether growth of age-1 fish declines or numbers of age-0 fish fall, the result of another decline in zooplankton density will be a reduction in the production of alewives needed to support piscivores.

  11. Alewives and rainbow smelt in Lake Huron: midwater and bottom aggregations and estimates of standing stocks

    USGS Publications Warehouse

    Argyle, Ray L.

    1982-01-01

    The continued availability of adequate amounts of forage fish, primarily alewives Alosa pseudoharengus and rainbow smelt Osmerus mordax, is critical to the success of ongoing programs aimed at rebuilding lake trout Salvelinus namaycush populations and maintaining other salmonid stocks in Lake Huron. These forage species are distributed at middepths as well as on or near the bottom. Acoustic methods were integrated with midwater and bottom trawling to characterize the population and estimate the biomass of the forage stocks. The average sizes of alewives and rainbow smelt caught at middepths were smaller than those caught in bottom trawls; however, most size ranges in the bottom trawl catches were also present in the midwater catches. Subadult and adult fish (both species) were rarely caught concurrently in midwater and when they were caught together the fish were invariably large subadults and small adults. Biomass estimates for the pelagic component were determined from trawl catches and echogram counts. The regression of echogram counts (X) on trawl catches (Y) was Y = -2.69 + 0.983X (r2 = 0.766) at the fish densities investigated. The pelagic biomasses of alewives and rainbow smelt in United States waters of Lake Huron were estimated at 17,200 t in July 1974, 22,000 t in July 1975, and 19,000 t in August 1976. Biomass estimates of the stocks in midwater were usually larger in spring than in fall, probably due to seasonal differences in distribution rather than in abundance. Estimates for the demersal component of the combined alewife-rainbow smelt forage stock, calculated from stratified random sampling of the spring bottom trawl catches for 1973 through 1980 went from 35,000 t in 1973, to a high of 83,000 t in 1975, and to 72,000 t in 1980; the estimates in fall went from 31,000 t in 1973, to a high of 56,000 t in 1977, and to 43,000 t in 1980. Biomass estimates calculated from spring catch data were usually larger than those calculated from fall data

  12. Evaluation of nature-like and technical fishways for the passage of alewives at two coastal streams in New England

    USGS Publications Warehouse

    Franklin, Abigail E.; Haro, Alex; Castro-Santos, Theodore; Noreika, John

    2012-01-01

    Nature-like fishways have been designed with the intent to reconnect river corridors and provide passage for all species occurring in a system. The approach is gaining popularity both in Europe and North America, but performance of these designs has not been quantitatively evaluated in a field setting for any North American species. Two nature-like fishways and three technical fishways in New England were evaluated for passage of anadromous adult alewives Alosa pseudoharengus by using passive integrated transponder (PIT) telemetry. A perturbation boulder rock ramp (32 m long; 4.2% slope) constructed in Town Brook (Plymouth, Massachusetts) passed 94% of the fish that made passage attempts, with most fish ascending the ramp in less than 22 min. In the East River (Guilford, Connecticut), a step-pool bypass design (48 m long; 7.1% slope) passed only 40% of attempting fish, with a median transit time of 75 min. In Town Brook, a technical pool-and-weir fishway (14 m long; 14.3% slope) exhibited poor entry and poor passage for the fish. In contrast, in the East River, two technical steeppass fishways (3 m long; 29.6% and 9.6% slopes) passed the majority of available fish, although one of these steeppass fishways may have lacked sufficient flow to attract fish to the entrance. In both Town Brook and the East River, tagged fish passed rapidly downstream through all fishways after spawning. In the East River, the amount of time fish spent in the spawning habitat before migrating downstream ranged from 1 to 41 d. These studies demonstrate that some nature-like and technical fishway designs can effectively facilitate passage of alewives, but a fishway's location in relation to a spillway is important, and further evaluations are required to more precisely identify the influence of the vertical drop per pool and the specific local hydraulics on alewife behaviors and passage performance.

  13. Spatially explicit measures of production of young alewives in Lake Michigan: Linkage between essential fish habitat and recruitment

    USGS Publications Warehouse

    Hook, Tomas O.; Rutherford, Edward S.; Brines, Shannon J.; Mason, Doran M.; Schwab, David J.; McCormick, Michael; Desorcie, Timothy J.

    2003-01-01

    The identification and protection of essential habitats for early life stages of fishes are necessary to sustain fish stocks. Essential fish habitat for early life stages may be defined as areas where fish densities, growth, survival, or production rates are relatively high. To identify critical habitats for young-of-year (YOY) alewives (Alosa pseud oharengus) in Lake Michigan, we integrated bioenergetics models with GIS (Geographic Information Systems) to generate spatially explicit estimates of potential population production (an index of habitat quality). These estimates were based upon YOY alewife bioenergetic growth rate potential and their salmonine predators’ consumptive demand. We compared estimates of potential population production to YOY alewife yield (an index of habitat importance). Our analysis suggested that during 1994–1995, YOY alewife habitat quality and yield varied widely throughout Lake Michigan. Spatial patterns of alewife yield were not significantly correlated to habitat quality. Various mechanisms (e.g., predator migrations, lake circulation patterns, alternative strategies) may preclude YOY alewives from concentrating in areas of high habitat quality in Lake Michigan.

  14. Spawning behaviour of Allis shad Alosa alosa: new insights based on imaging sonar data.

    PubMed

    Langkau, M C; Clavé, D; Schmidt, M B; Borcherding, J

    2016-06-01

    Spawning behaviour of Alosa alosa was observed by high resolution imaging sonar. Detected clouds of sexual products and micro bubbles served as a potential indicator of spawning activity. Peak spawning time was between 0130 and 0200 hours at night. Increasing detections over three consecutive nights were consistent with sounds of mating events (bulls) assessed in hearing surveys in parallel to the hydro acoustic detection. In 70% of the analysed mating events there were no additional A. alosa joining the event whilst 70% of the mating events showed one or two A. alosa leaving the cloud. In 31% of the analysed mating events, however, three or more A. alosa were leaving the clouds, indicating that matings are not restricted to a pair. Imaging sonar is suitable for monitoring spawning activity and behaviour of anadromous clupeids in their spawning habitats.

  15. Species Profiles. Life Histories and Environmental Requirements of Coastal Fishes and Invertebrates (North Atlantic). Atlantic Herring,

    DTIC Science & Technology

    1986-04-01

    from alewives (Alosa pseudoharengus) economy (Briggs et al. 1982). The and shads (Alosa spp.): the point of average annual value of Maine herring origin...D.J. Wildish, and R.H. pp. Peterson. 1981. Possible impact 20 .. .. , ,,n ,nnmm, m mm • ~ mlm mBNIN - - !| from dredging and spoil disposal on...a herring (Clu__ a No. 1008. 33 pp. harengus L.) spawning bed in Miramichi Bay, New Brunswick. Can. Meyer, H.A. 1878. Beobachtungen uber Tech. Rep

  16. Macroparasites of allis shad (Alosa alosa) and twaite shad (Alosa fallax) of the Western Iberian Peninsula Rivers: ecological, phylogenetic and zoonotic insights.

    PubMed

    Bao, M; Roura, A; Mota, M; Nachón, D J; Antunes, C; Cobo, F; MacKenzie, K; Pascual, S

    2015-10-01

    Samples of anadromous Alosa alosa (Clupeidae) (n = 163) and Alosa fallax (Clupeidae) (n = 223), caught in Western Iberian Peninsula Rivers from 2008 to 2013, were examined for buccal, branchial and internal macroparasites, which were identified using morphological and molecular methods. Alosa alosa were infected with Anisakis simplex s.s., Anisakis pegreffii, Hysterothylacium aduncum, Rhadinorhynchus pristis, Mazocraes alosae, Hemiurus appendiculatus, Ceratothoa italica and an unidentified ergasilid copepod. Ceratothoa italica represents a new host record for A. alosa. Alosa fallax were infected with A. simplex s.s., A. pegreffii, H. aduncum, H. appendiculatus, Clavellisa emarginata and an unidentified cymothoid isopod. This is the first report of C. italica, C. emarginata and M. alosae in the Iberian Peninsula. The phylogenetic positions of M. alosae, H. appendiculatus and C. emarginata were assessed using 18S and 28S ribosomal RNA (rRNA); our contributions provide a better understanding of the phylogenetic relationships within their groups. Qualitative and quantitative differences in the parasite faunas of these two shad species are consistent with different feeding strategies. The results provide information about host migration behaviour and transmission pathways through diet during the marine trophic phase of the shad's life cycle and their roles as paratenic or final hosts and transporters of parasites between seawater and freshwater environments. The zoonotic parasites A. simplex s.s. and A. pegreffii pose a risk for consumers or riverine mammals (e.g. European otter). The use of parasites as biological tags for shad stocks in Western Iberian Rivers could be a useful approach in multidisciplinary studies concerning fish stock delimitation and characterization.

  17. Posthandling survival and PIT tag retention by alewives—a comparison of gastric and surgical implants

    USGS Publications Warehouse

    Castro-Santos, Theodore; Voni, Volney

    2013-01-01

    We compared survival and tag retention of Alewives Alosa pseudoharengus tagged with PIT tags, using intraperitoneal (IP) surgical implants, gastric implants (GI), and untagged controls held for 38 d. Retention was 100% for IP-tagged Alewives and 98% for GI-tagged implants. No significant difference in survival was observed among any of these groups. These results lend support to the use of PIT telemetry for studying fish passage and migration of anadromous herring. Both methods hold promise for improving estimates of freshwater survival of adult anadromous clupeids; further research should make it also possible to refine estimates of adult marine survival.

  18. Comparative phylogeography and demographic history of European shads (Alosa alosa and A. fallax) inferred from mitochondrial DNA

    PubMed Central

    2012-01-01

    Background Comparative broad-scale phylogeographic studies of aquatic organisms provide insights on biotic responses to the paleohydrological dynamics associated with climatic oscillations. These insights can be used to formulate a framework for understanding the evolutionary history of a species or closely related taxa as well as aid in predictive modeling of further responses to climate change. Anadromous fishes constitute interesting models for understanding the relative importance of environmental versus biological factors in shaping intraspecific genetic substructure on the interface between marine and freshwater realms. European shads, Alosa alosa and A. fallax are anadromous species that have persisted through historical large-scale environmental perturbations and now additionally face an array of anthropogenic challenges. A comprehensive phylogeographic investigation of these species is needed to provide insights on both the historical processes that have shaped their extant genetic structure and diversity, and the prospects for their future management and conservation. Results Despite introgressive hybridization, A. alosa and A. fallax are genetically divergent, congruent with previous studies. Three similarly divergent mtDNA clades were recognized within both A. fallax and A. alosa, most likely originating during common periods of isolation during the Pleistocene among the studied oceanographic regions. Periods of basin isolation apparently extended to the Black Sea as additional Alosa clades occur there. The present day geographic distribution of genetic diversity within European Alosa sp. suggests the existence of a strong but permeable barrier between the Atlantic and Mediterranean seas, as shown for a number of other aquatic species. Overall mtDNA diversity is considerably lower for A. alosa compared to A. fallax, suggesting that the former species is more sensitive to climatic as well as anthropogenic changes. For A. fallax, migration from the

  19. First evidence of natural reproduction of the Allis shad Alosa alosa in the River Rhine following re-introduction measures.

    PubMed

    Hundt, M; Scharbert, A; Weibel, U; Kuhn, G; Metzner, K; Jatteau, P; Pies, A; Schulz, R; Gergs, R

    2015-08-01

    After stocking with larvae from the Gironde-Garonne-Dordogne population, in 2013, three young-of-the-year Allis shad Alosa alosa, probably originating from natural reproduction, were documented for the first time in a period of nearly 100 years in the River Rhine. In 2014, a further increase was observed when 57 juveniles and eight adults were caught; seven of these eight adults were derived from stocking, indicating the success of stocking measures within the framework of the EU-LIFE project.

  20. Impacts of changing food webs in Lake Ontario: Implications of dietary fatty acids on growth of alewives

    USGS Publications Warehouse

    Snyder, R.J.; Demarche, C.J.; Honeyfield, D.C.

    2011-01-01

    Declines in the abundance and condition of Great Lakes Alewives have been reported periodically during the last two decades, and the reasons for these declines remain unclear. To better understand how food web changes may influence Alewife growth and Wisconsin growth model predictions, we fed Alewives isocaloric diets high in omega-6 fatty acids (corn oil) or high in omega-3 fatty acids (fish oil). Alewives were fed the experimental diets at either 1% ("low ration") or 3% ("high ration") of their wet body weight per day. After six weeks, Alewives maintained on the high ration diets were significantly larger than those fed the low ration diets. Moreover, Alewives given the high ration fish oil diet were significantly larger than those maintained on the high ration corn oil diet after six weeks of growth. Body lipid, energy density and total body energy of Alewives on the high ration diets were significantly higher than those fed the low ration diets, and total body energy was significantly higher in Alewives given the high ration fish oil diet compared to those on the high ration corn oil diet. The current Wisconsin bioenergetics model underestimated growth and overestimated food consumption by Alewives in our study. Alewife thiaminase activity was similar among treatment groups. Overall, our results suggest that future food web changes in Lake Ontario, particularly if they involve decreases in the abundance of lipid rich prey items such as Mysis, may reduce Alewife growth rates and total body energy due to reductions in the availability of dietary omega-3 fatty acids. ?? 2011 AEHMS.

  1. Egg fatty acid composition from lake trout fed two Lake Michigan prey fish species.

    USGS Publications Warehouse

    Honeyfield, D.C.; Fitzsimons, J.D.; Tillitt, D.E.; Brown, S.B.

    2009-01-01

    We previously demonstrated that there were significant differences in the egg thiamine content in lake trout Salvelinus namaycush fed two Lake Michigan prey fish (alewife Alosa pseudoharengus and bloater Coregonus hoyi). Lake trout fed alewives produced eggs low in thiamine, but it was unknown whether the consumption of alewives affected other nutritionally important components. In this study we investigated the fatty acid composition of lake trout eggs when females were fed diets that resulted in different egg thiamine concentrations. For 2 years, adult lake trout were fed diets consisting of four combinations of captured alewives and bloaters (100% alewives; 65% alewives, 35% bloaters; 35% alewives, 65% bloaters; and 100% bloaters). The alewife fatty acid profile had higher concentrations of arachidonic acid and total omega-6 fatty acids than the bloater profile. The concentrations of four fatty acids (cis-13, 16-docosadienoic, eicosapentaenoic, docosapentaenoic, and docosahexaenoic acids) were higher in bloaters than in alewives. Although six fatty acid components were higher in lake trout eggs in 2001 than in 2000 and eight fatty acids were lower, diet had no effect on any fatty acid concentration measured in lake trout eggs in this study. Based on these results, it appears that egg fatty acid concentrations differ between years but that the egg fatty acid profile does not reflect the alewife-bloater mix in the diet of adults. The essential fatty acid content of lake trout eggs from females fed alewives and bloaters appears to be physiologically regulated and adequate to meet the requirements of developing embryos.

  2. Prey fish dynamics and salmonine predator growth in Lake Ontario, 1978-84

    USGS Publications Warehouse

    O'Gorman, Robert; Bergstedt, Roger A.; Eckert, Thomas H.

    1987-01-01

    The size of hatchery-reared brown trout (Salmo trutta) and coho salmon (Oncorhynchus kisutch), 1 yr after release in Lake Ontario, declined when the stocking of salmonines was increased between 1978 and 1984. The principal prey species, alewife (Alosa pseudoharengus) and rainbow smelt (Osmerus mordax), failed to show the expected, predator-induced downturn in abundance. Instead, rainbow smelt remained moderately abundant and alewives very abundant. During this period, alewife year-classes were small, survival of yearling alewives was poor, growth of young-of-the-year of both alewives and rainbow smelt was slow (growth of most older alewives ceased), and rainbow smelt numbers gradually increased (the much larger alewife population presumably buffered older rainbow smelt from predation by large piscivores). When adult alewife numbers were halved by a winter die-off, the subsequent year-class of alewives was large and growth of brown trout during their first year in the lake increased. This suggested a causal relation between abundance of young alewives and brown trout growth. In the first year coho salmon were at liberty, their growth was related to abundance of young-of-the-year alewives; in their second year it was related to the abundance of yearling alewives and the condition of adult alewives. We hypothesize that abundant adult alewives suppressed production of young-of-the-year fish (necessary prey for salmonines during their first year in the lake) through competition for limited zooplankton production, and thus impeded the transfer of energy from the lowest trophic level to young salmonine predators.

  3. Intraspecific variation in a predator affects community structure and cascading trophic interactions.

    PubMed

    Post, David M; Palkovacs, Eric P; Schielke, Erika G; Dodson, Stanley I

    2008-07-01

    Intraspecific phenotypic variation in ecologically important traits is widespread and important for evolutionary processes, but its effects on community and ecosystem processes are poorly understood. We use life history differences among populations of alewives, Alosa pseudoharengus, to test the effects of intraspecific phenotypic variation in a predator on pelagic zooplankton community structure and the strength of cascading trophic interactions. We focus on the effects of differences in (1) the duration of residence in fresh water (either seasonal or year-round) and (2) differences in foraging morphology, both of which may strongly influence interactions between alewives and their prey. We measured zooplankton community structure, algal biomass, and spring total phosphorus in lakes that contained landlocked, anadromous, or no alewives. Both the duration of residence and the intraspecific variation in foraging morphology strongly influenced zooplankton community structure. Lakes with landlocked alewives had small-bodied zooplankton year-round, and lakes with no alewives had large-bodied zooplankton year-round. In contrast, zooplankton communities in lakes with anadromous alewives cycled between large-bodied zooplankton in the winter and spring and small-bodied zooplankton in the summer. In summer, differences in feeding morphology of alewives caused zooplankton biomass to be lower and body size to be smaller in lakes with anadromous alewives than in lakes with landlocked alewives. Furthermore, intraspecific variation altered the strength of the trophic cascade caused by alewives. Our results demonstrate that intraspecific phenotypic variation of predators can regulate community structure and ecosystem processes by modifying the form and strength of complex trophic interactions.

  4. Distribution and abundance of larval fish in the nearshore waters of western Lake Huron

    USGS Publications Warehouse

    O'Gorman, Robert

    1983-01-01

    Ichthyoplankton was collected at 17 nearshore (bottom depth ≥5 m but ≤10 m) sites in western Lake Huron during 1973–75 with a 0.5-m net of 351-micron mesh towed at 99 m/min. Larvae of rainbow smelt (Osmerus mordax) dominated late spring and early summer catches and larvae of alewives (Alosa pseudoharengus) the midsummer catches. Larval yellow perch (Perca flavescens) were caught in early summer but were rarely the dominant species. The time of spawning and hatching, and thus occurrence of larvae, differed between areas but was less variable for alewives than for yellow perch. The appearance of larvae in Saginaw Bay was followed successively by their appearance in southern, central, and northern Lake Huron. Rainbow smelt were most abundant in northern Lake Huron and yellow perch and alewives in inner Saginaw Bay. Densities of either rainbow smelt or alewives occasionally exceeded 1/m3, whereas those of yellow perch never exceeded 0.1/m3. Abundance of alewives was usually highest 1 to 3 m beneath the surface and that of rainbow smelt 2 to at least 6 m beneath the surface. Important nursery areas of rainbow smelt were in bays and off irregular coastlines and those of yellow perch were in bays. All nearshore waters seemed equally important as nursery areas of alewives.

  5. Anisakis infection in allis shad, Alosa alosa (Linnaeus, 1758), and twaite shad, Alosa fallax (Lacépède, 1803), from Western Iberian Peninsula Rivers: zoonotic and ecological implications.

    PubMed

    Bao, M; Mota, M; Nachón, D J; Antunes, C; Cobo, F; Garci, M E; Pierce, G J; Pascual, S

    2015-06-01

    Spawning individuals of allis shad, Alosa alosa (Linnaeus, 1758), and twaite shad, Alosa fallax (Lacépède, 1803), were sampled from three rivers on the Atlantic coast of the Iberian Peninsula (Ulla, Minho, Mondego) during 2008 to 2013 to assess the presence of the zoonotic marine parasite Anisakis spp. larvae. The results revealed that both shad species were infected by third-larval stage Anisakis simplex s.s. and Anisakis pegreffii. The latter is reported in mixed infections in both shad species of Western Iberian Peninsula for the first time. In A. alosa, the prevalence of Anisakis infection can reach 100%, while in A. fallax, prevalence was up to 83%. Infected individuals of the former species also often contain much higher number of parasites in theirs internal organs and flesh: from 1 to 1138 Anisakis spp. larvae as compared to 1 to 121 larvae, respectively. In general, numbers of A. pegreffii were higher than those of A. simplex s.s. Our results suggest that in the marine environment of the Western Iberian Peninsula, both anadromous shad species act as paratenic hosts for A. simplex s.s. and A. pegreffii, thus widening the distribution of the infective nematode larvae from the marine to the freshwater ecosystem. This finding is of great epidemiological relevance for wildlife managers and consumers, considering the zoonotic and gastroallergic threats posed of these parasites.

  6. Development of thiamine deficiencies and early mortality syndrome in lake trout by feeding experimental and feral fish diets containing thiaminase

    USGS Publications Warehouse

    Honeyfield, D.C.; Hinterkopf, J.P.; Fitzsimons, J.D.; Tillitt, D.E.; Zajicek, J.L.; Brown, S.B.

    2005-01-01

    We conducted a laboratory investigation on the consequences of feeding predatory salmonids either experimental diets low in thiamine or diets containing alewife Alosa pseudoharengus. In experiment 1, adult lake trout Salvelinus namaycush were fed experimental diets containing bacterial thiaminase. In experiment 2, adult lake trout were fed natural prey species, alewives, and bloaters Coregonus hoyi. The diets consisted of four combinations of alewives and bloaters from Lake Michigan (100% alewives, 65% alewives–35% bloaters, 35% alewives–65% bloaters, and 100% bloaters), alewives from Cayuga Lake, a casein bacterial thiaminase, and a commercial trout diet. We assessed the effects of each diet on egg thiamine concentration and incidence of an embryonic early mortality syndrome (EMS). In experiment 1, incidence of EMS ranged from 0% to 100%. Significant relationships were found between the incidence of EMS and thiamine. In experiment 2, adult lake trout fed 100% alewives from either Lake Michigan or Cayuga Lake or fish fed the casein bacterial thiaminase diet produced eggs with low thiamine and swim-up fry with EMS. At either 35% or 65% alewives in the diet, egg thiamine was significantly lowered. The number of females that produced offspring that died from EMS were low but demonstrated the negative potential if feral lake trout foraged on either 35% or 65% alewives. Depleted egg thiamine and the onset of EMS required diets containing thiaminase for a minimum of 2 years in lake trout initially fully thiamine replete. We conclude that EMS can be caused by extensive feeding on 100% alewives and dietary levels of 35% or greater may prove detrimental to sustainable reproduction of salmonids in the Great Lakes. The data are consistent with that observed in feral lake trout, and it is concluded that EMS is the result of a thiamine deficiency.

  7. Evaluating the effect of stressors on thiaminase activity in alewife

    USGS Publications Warehouse

    Lepak, J.M.; Kraft, C.E.; Honeyfield, D.C.; Brown, S.B.

    2008-01-01

    No consistent explanation has been found for the variability in the thiaminase activity of alewives Alosa pseudoharengus despite the role of alewife thiaminase in large-scale salmonine mortality in the Laurentian Great Lakes. We conducted experiments to evaluate the effect of two stressors, reduced salt content in the water and food limitation, on alewife thiaminase activity. Alewives were subjected to treatments in replicated tanks in which conductivity was lowered (<100 ??S/cm) for 8 d and feeding was limited for 39 d. Circulating white blood cells, plasma cortisol, plasma glucose, and whole-body thiaminase were measured in individual alewives to assess their response to these experimental treatments. Alewives from the controls had significantly larger numbers of circulating white blood cells than those in the salt-reduced and food-limited treatments (24,000 and 19,000 cells/??L and 11,000 and 9,000 cells/??L for alewives from the two control and salt-reduced treatment tanks, respectively, and 34,000 and 30,000 cells/??L and 21,000 and 16,000 cells/??L for alewives from the two control and food-limited treatment tanks). No significant differences in alewife thiaminase activity were found between treatment fish and their controls. The mean thiaminase activity in the alewives studied increased from 6,900 to 16,000 pmol??g -1??min-1 from the time of their collection in Cayuga Lake to the start of laboratory experiments 1.5-2.5 years later; the latter value was more than twice that of previously reported levels of thiaminase activity from alewives collected in the wild. These data suggest that the variability in alewife thiaminase is not related to stress from salt reduction or food limitation, but laboratory holding conditions significantly increased thiaminase through a mechanism not evaluated by our experimental treatments. ?? Copyright by the American Fisheries Society 2008.

  8. Spring-summer diet of lake trout on Six Fathom Bank and Yankee Reef in Lake Huron

    USGS Publications Warehouse

    Madenjian, C.P.; Holuszko, J.D.; Desorcie, T.J.

    2006-01-01

    We examined the stomach contents of 1,045 lake trout (Salvelinus namaycush) caught on Six Fathom Bank and Yankee Reef, two offshore reef complexes in Lake Huron, during late spring and early summer 1998-2003. Lake trout ranged in total length from 213 to 858 mm, and in age from 2 to 14 years. In total, 742 stomachs contained food. On a wet-weight basis, alewife (Alosa pseudoharengus) dominated the spring-summer diet of lake trout on both of these offshore reef complexes. Alewives accounted for 75 to 90% of lake trout diet, depending on the lake trout size category. Size of alewives found in lake trout stomachs increased with increasing lake trout size. Faster growth of juvenile lake trout on Six Fathom Bank and Yankee Reef than on Sheboygan Reef in Lake Michigan was attributed to greater availability of small alewives on the offshore reefs in Lake Huron. Our findings indicated that alewives inhabited Six Fathom Bank and Yankee Reef during spring and summer months. Thus, our study provided support for the contention that alewives may have interfered with natural reproduction by lake trout on these offshore reef complexes in Lake Huron.

  9. Distribution, abundance, and biology of the alewife in U.S. waters of Lake Superior

    USGS Publications Warehouse

    Bronte, Charles R.; Selgeby, James H.; Curtis, Gary L.

    1991-01-01

    Alewives (Alosa pseudoharengus) were first reported in Lake Superior in 1954 and gradually increased in abundance in the late 1950s. In the 1960s and early 1970s, the fish were widespread in the lake but scarce. We determined the more recent abundance and distribution of alewives by cross-contour trawling in the spring in 1978–1988. Alewives were scarce lake-wide; the mean catch rate was only 23 fish per 100 h of trawling and represented a density of 0.003 kg per hectare in the area swept by the trawls. Fish of six age groups were caught in trawls in spring and gill nets in fall in 1983–1987. Total annual mortality was 64%, a high natural rate in the absence of fishing. Alewives in Lake Superior were small at the end of their first growing season but later grew faster than those in the other Great Lakes. Fecundity, estimated to be 64,000 eggs (mean total length = 187 mm) was higher than in other freshwater stocks. Zooplankton was the major food of alewives < 100 mm long and Mysis was the main food of larger fish. Exposure to water temperatures below lethal minimums for overwintering fish and for developing eggs limits the success of this species in Lake Superior.

  10. The influence of alewife year-class strength on prey selection and abundance of age-1 Chinook salmon in Lake Michigan

    USGS Publications Warehouse

    Warner, D.M.; Kiley, C.S.; Claramunt, R.M.; Clapp, D.F.

    2008-01-01

    We used growth and diet data from a fishery-independent survey of Chinook salmon Oncorhynchus tshawytscha, acoustic estimates of prey density and biomass, and statistical catch-at-age modeling to study the influence of the year-class strength of alewife Alosa pseudoharengus on the prey selection and abundance of age-1 Chinook salmon in Lake Michigan during the years 1992-1996 and 2001-2005. Alewives age 2 or younger were a large part of age-1 Chinook salmon diets but were not selectively fed upon by age-1 Chinook salmon in most years. Feeding by age-1 Chinook salmon on alewives age 2 or younger became selective as the biomass of alewives in that young age bracket increased, and age-1 Chinook salmon also fed selectively on young bloaters Coregonus hoyi when bloater density was high. Selection of older alewives decreased at high densities of alewives age 2 or younger and, in some cases, high densities of bloater. The weight and condition of age-1 Chinook salmon were not related to age-1 Chinook salmon abundance or prey abundance, but the abundance of age-1 Chinook salmon in year t was positively related to the density of age-0 alewives in year t - 1. Our results suggest that alewife year-class strength exerts a positive bottom-up influence on age-1 Chinook salmon abundance, prey switching behavior by young Chinook salmon contributing to the stability of the predator-prey relationship between Chinook salmon and alewives. ?? Copyright by the American Fisheries Society 2008.

  11. Native rainbow smelt and nonnative alewife distribution related to temperature and light gradients in Lake Champlain

    USGS Publications Warehouse

    Parrish, Donna; Simonin, Paul W.; Rudstam, Lars G.; Sullivan, Patrick J.; Pientka, Bernard

    2012-01-01

    Alewife (Alosa pseudoharengus) recently became established in Lake Champlain and may compete with native rainbow smelt (Osmerus mordax) for food or consume larval rainbow smelt. The strength of this effect depends partly on the spatial and temporal overlap of different age groups of the two species; therefore, we need a better understanding of factors affecting alewife and rainbow smelt distributions in Lake Champlain. We used hydroacoustics, trawls, and gill nets to document vertical fish distribution, and recorded environmental data during 16 day–night surveys over two years. Temperature, temperature change, and light were all predictors of adult and age-0 rainbow smelt distribution, and temperature and light were predictors of age-0 alewives' distribution (based on GAMM models evaluated with AIC). Adult alewives were 5–30 m shallower and age-0 alewives were 2–15 m shallower than their rainbow smelt counterparts. Adult rainbow smelt distribution overlapped with age-0 rainbow smelt and age-0 alewives near the thermocline (10–25 m), whereas adult alewives were shallower (0–6 m) and overlapped with age-0 alewives and rainbow smelt in the epilimnion. Adult rainbow smelt were in water < 10–12 °C, whereas age-0 rainbow smelt were in 10–20 °C, and adult and age-0 alewives were in 15–22 °C water. Predicting these species distributions is necessary for quantifying the strength of predatory and competitive interactions between alewife and rainbow smelt, as well as between alewife and other fish species in Lake Champlain.

  12. Multibeam sonar (DIDSON) assessment of American shad (Alosa sapidissima) approaching a hydroelectric dam

    USGS Publications Warehouse

    Grote, Ann B.; Bailey, Michael M.; Zydlewski, Joseph; Hightower, Joseph E.

    2014-01-01

    We investigated the fish community approaching the Veazie Dam on the Penobscot River, Maine, prior to implementation of a major dam removal and river restoration project. Multibeam sonar (dual-frequency identification sonar, DIDSON) surveys were conducted continuously at the fishway entrance from May to July in 2011. A 5% subsample of DIDSON data contained 43 793 fish targets, the majority of which were of Excellent (15.7%) or Good (73.01%) observation quality. Excellent quality DIDSON targets (n = 6876) were apportioned by species using a Bayesian mixture model based on four known fork length distributions (river herring (alewife,Alosa psuedoharengus, and blueback herring, Alosa aestivalis), American shad, Alosa sapidissima) and two size classes (one sea-winter and multi-sea-winter) of Atlantic salmon (Salmo salar). 76.2% of targets were assigned to the American shad distribution; Atlantic salmon accounted for 15.64%, and river herring 8.16% of observed targets. Shad-sized (99.0%) and salmon-sized (99.3%) targets approached the fishway almost exclusively during the day, whereas river herring-sized targets were observed both during the day (51.1%) and at night (48.9%). This approach demonstrates how multibeam sonar imaging can be used to evaluate community composition and species-specific movement patterns in systems where there is little overlap in the length distributions of target species.

  13. Organochlorinated pesticides, PCBs, dioxins, and PBDEs in grey mullets (Liza ramada) and allis shads (Alosa alosa) from the Vilaine estuary (France).

    PubMed

    Bocquené, Gilles; Abarnou, Alain

    2013-02-01

    This study aimed to compare the contamination levels of various organohalogenated compounds in two migratory fish species in the Vilaine River in western France. Organochlorinated pesticides, polychlorinated biphenyls (PCBs), dioxins (polychlorinated dibenzo-p-dioxins/dibenzofurans (PCDDs/Fs)), and polybrominated diphenyl ethers (PBDEs) were analyzed in two diadromous species from the Vilaine estuary, the grey mullet (Liza ramada)-an amphihaline species, and the allis shad (Alosa alosa)-an anadromous species. Fish were collected in spring 2004 and spring 2005, upstream and downstream of the Arzal Dam. PCB contamination varied from 27 to 200 ng g(-1) dry weight (d.w.). PCDDs/Fs, expressed in toxicity equivalent quantity (TEQ) varied from 0.4 to 2.8 pg g(-1) d.w. Dioxins and dioxin-like PCBs expressed in total TEQ varied from 1.4 to 18.8 pg g(-1) d.w. PBDE47 was present at around 2-10 ng g(-1) d.w. and concentrations of the insecticide dichlorodiphenyltrichloroethane breakdown product p,p'-dichlorodiphenylchloroethylene varied from 1 to 14 ng g(-1) d.w. For both species, specimens collected upstream were more contaminated. The grey mullet specimens were less contaminated than the allis shad when taken downstream of the dam but were more contaminated upstream. The allis shads presented intermediate contaminant concentrations with a less pronounced difference between upstream and downstream specimens. However, it is thought that shads do not feed when they spawn in the upstream parts of rivers, which should modify the contaminant concentrations. However, measurements in upstream shad samples show an unexpected increase of the contamination, which remains unexplained.

  14. Regional variation in muscle metabolic enzymes in individual American shad (Alosa sapidissima)

    USGS Publications Warehouse

    Leonard, J.B.K.

    1999-01-01

    Evaluation of the activity of metabolic enzymes is often used to asses metabolic capacity at the tissue level, but the amount of regional variability within a tissue in an individual fish of a given species is frequently unknown. The activities of four enzymes (citrate synthase (CS), phosphofructokinase, lactate dehydrogenase (LDH), and ??-hydroxyacyl coenzyme A dehydrogenase (HOAD) were assayed in red and white muscle at 10 sites along the body of adult American shad (Alosa sapidissima). Red and white muscle HOAD and white muscle CS and LDH varied significantly, generally increasing posteriorly. Maximal variation occurs in red muscle HOAD (~450%) and white muscle LDH (~60%) activity. Differences between the sexes also vary with sampling location. This study suggests that the variability in enzyme activity may be linked to functional differences in the muscle at different locations, and also provides guidelines for sample collection in this species.

  15. The nematode Anisakis simplex in American shad (Alosa sapidissima) in two Oregon rivers.

    PubMed

    Shields, B A; Bird, P; Liss, W J; Groves, K L; Olson, R; Rossignol, P A

    2002-10-01

    This paper represents the first report of the nematode Anisakis simplex in the American shad (Alosa sapidissima) in its introduced range in the American Pacific Northwest. All the adult shad sampled from spawning populations in the Willamette (n = 9) and Umpqua (n = 12) rivers were infected with A. simplex with intensities ranging from 6 to 89 worms per fish. This preliminary investigation contrasts sharply with previous studies in the native range of American shad and confirms that this fish may be an important intermediate host for A. simplex in the Pacific Northwest. It is suggested that this new parasite-host relationship has led to an ecological expansion into rivers and Anisakis may present an emerging health risk for wildlife and some human consumers.

  16. Trade-offs in osmoregulation and parallel shifts in molecular function follow ecological transitions to freshwater in the Alewife

    USGS Publications Warehouse

    Velotta, Jonathan P.; McCormick, Stephen; Schultz, Eric T.

    2015-01-01

    Adaptation to freshwater may be expected to reduce performance in seawater because these environments represent opposing selective regimes. We tested for such a trade-off in populations of the Alewife (Alosa pseudoharengus). Alewives are ancestrally anadromous, and multiple populations have been independently restricted to freshwater (landlocked). We conducted salinity challenge experiments, whereby juvenile Alewives from one anadromous and multiple landlocked populations were exposed to freshwater and seawater on acute and acclimation timescales. In response to acute salinity challenge trials, independently derived landlocked populations varied in the degree to which seawater tolerance has been lost. In laboratory-acclimation experiments, landlocked Alewives exhibited improved freshwater tolerance, which was correlated with reductions in seawater tolerance and hypo-osmotic balance, suggesting that trade-offs in osmoregulation may be associated with local adaptation to freshwater. We detected differentiation between life-history forms in the expression of an ion-uptake gene (NHE3), and in gill Na+/K+-ATPase activity. Trade-offs in osmoregulation, therefore, may be mediated by differentiation in ion-uptake and salt-secreting pathways.

  17. Thiamine and fatty acid content of walleye tissue from three southern U.S. reservoirs

    USGS Publications Warehouse

    Honeyfield, D.C.; Vandergoot, C.S.; Bettoli, P.W.; Hinterkopf, J.P.; Zajicek, J.L.

    2007-01-01

    We determined the thiamine concentration in egg, muscle, and liver tissues of walleyes Sander vitreus and the fatty acid content of walleye eggs from three southern U.S. reservoirs. In two Tennessee reservoirs (Dale Hollow and Center Hill), in which there were alewives Alosa pseudoharengus in the forage base, natural recruitment of walleyes was not occurring; by contrast in Lake James Reservoir, North Carolina, where there were no alewives, the walleye population was sustained via natural recruitment. Female walleye tissues were collected and assayed for thiamine (vitamin B1) and fatty acid content. Thiamine pyrophosphate was found to be the predominant form of thiamine in walleye eggs. In 2000, mean total egg thiamine concentrations were similar among Center Hill, Dale Hollow, and Lake James reservoirs (2.13, 3.14, and 2.77 nmol thiamine/g, respectively). Egg thiamine concentration increased as maternal muscle (r 2 = 0.73) and liver (r2 = 0.68) thiamine concentration increased. Walleye egg thiamine does not appear to be connected to poor natural reproduction in Tennessee walleyes. Threadfin shad Dorosoma petenense, which are found in all three reservoirs, had higher thiaminase activity than alewives. Six fatty acids differed among the walleye eggs for the three reservoirs. Two were physiologically important fatty acids, arachidonic acid (20:4[n-6]) and docosahexaenoic acid (22:6[n-3]), which are important eicosanoid precursors involved in the regulation of biological functions, such as immune response and reproduction. ?? Copyright by the American Fisheries Society 2007.

  18. Interactions between hatch dates, growth rates, and mortality of Age-0 native Rainbow Smelt and nonnative Alewife in Lake Champlain

    USGS Publications Warehouse

    Parrish, Donna; Simonin, Paul W.; Rudstam, Lars G.; Pientka, Bernard; Sullivan, Patrick J.

    2016-01-01

    Timing of hatch in fish populations can be critical for first-year survival and, therefore, year-class strength and subsequent species interactions. We compared hatch timing, growth rates, and subsequent mortality of age-0 Rainbow Smelt Osmerus mordax and Alewife Alosa pseudoharengus, two common open-water fish species of northern North America. In our study site, Lake Champlain, Rainbow Smelt hatched (beginning May 26) almost a month earlier than Alewives (June 20). Abundance in the sampling area was highest in July for age-0 Rainbow Smelt and August for age-0 Alewives. Late-hatching individuals of both species grew faster than those hatching earlier (0.6 mm/d versus 0.4 for Rainbow Smelt; 0.7 mm/d versus 0.6 for Alewives). Mean mortality rate during the first 45 d of life was 3.4%/d for age-0 Rainbow Smelt and was 5.5%/d for age-0 Alewives. Alewife mortality rates did not differ with hatch timing but daily mortality rates of Rainbow Smelt were highest for early-hatching fish. Cannibalism is probably the primary mortality source for age-0 Rainbow Smelt in this lake. Therefore, hatching earlier may not be advantageous because the overlap of adult and age-0 Rainbow Smelt is highest earlier in the season. However, Alewives, first documented in Lake Champlain in 2003, may increase the mortality of age-0 Rainbow Smelt in the summer, which should favor selection for earlier hatching.

  19. Chinook salmon foraging patterns in a changing Lake Michigan

    USGS Publications Warehouse

    Jacobs, Gregory R.; Madenjian, Charles P.; Bunnell, David B.; Warner, David M.; Claramunt, Randall M.

    2013-01-01

    Since Pacific salmon stocking began in Lake Michigan, managers have attempted to maintain salmon abundance at high levels within what can be sustained by available prey fishes, primarily Alewife Alosa pseudoharengus. Chinook Salmon Oncorhynchus tshawytscha are the primary apex predators in pelagic Lake Michigan and patterns in their prey selection (by species and size) may strongly influence pelagic prey fish communities in any given year. In 1994–1996, there were larger Alewives, relatively more abundant alternative prey species, fewer Chinook Salmon, and fewer invasive species in Lake Michigan than in 2009–2010. The years 2009–2010 were instead characterized by smaller, leaner Alewives, fewer alternative prey species, higher abundance of Chinook Salmon, a firmly established nonnative benthic community, and reduced abundance of Diporeia, an important food of Lake Michigan prey fish. We characterized Chinook Salmon diets, prey species selectivity, and prey size selectivity between 1994–1996 and 2009–2010 time periods. In 1994–1996, Alewife as prey represented a smaller percentage of Chinook Salmon diets than in 2009–2010, when alewife comprised over 90% of Chinook Salmon diets, possibly due to declines in alternative prey fish populations. The size of Alewives eaten by Chinook Salmon also decreased between these two time periods. For the largest Chinook Salmon in 2009–2010, the average size of Alewife prey was nearly 50 mm total length shorter than in 1994–1996. We suggest that changes in the Lake Michigan food web, such as the decline in Diporeia, may have contributed to the relatively low abundance of large Alewives during the late 2000s by heightening the effect of predation from top predators like Chinook Salmon, which have retained a preference for Alewife and now forage with greater frequency on smaller Alewives.

  20. The Peñalosa Principle of Transportation Democracy: Lessons from Bogotá on the Morality of Urban Mobility.

    PubMed

    Epting, Shane

    2016-12-01

    The mayor of Bogotá, Enrique Peñalosa strives to deliver transit services that promote social equity through bicycle lanes, improved sidewalks, and a world-famous Bus Rapid Transit (BRT) system, "TransMilenio." Through examining the principles that guide his planning, we can flesh out a starting point for socially just transit systems. While such measures can alleviate several harms that transit systems cause, they rest on an incomplete foundation due to their top-down nature. To amend this situation, the author argues for a restorative justice approach to transportation democracy, using examples from Peñalosa's mayoral tenure. In turn, lessons from Bogotá's transportation history reveal how to develop transit systems that strongly favor justice.

  1. Alewife dieoffs: Why do they occur?

    USGS Publications Warehouse

    Colby, Peter J.

    1971-01-01

    Periodid midwinter, early spring, and summer mortalities of alewives (Alosa pseudoharengus) have been common in the Great Lakes since the first appearance of the silvery marine invader in Lake Ontario in the mid-1870's. In 1967 a nationally publicized dieoff of tremendous magnitude (estimated at several hundred million pounds of fish) in Lake Michigan resulted in losses to industry,municipalities, and recreational interests in excess of $100 million. The cause of these mortalities is still unclear. The apparent inability of this primarily marine species to adjust completely to the Great Lakes has several suspected causes, among which failure to adjust to temperature extremes and fluctuations in the Great Lakes now appears to be of primary importance. Other possible causes are exhaustion of the food supply, failure to osmoregulate (maintain a suitable chemical balance) adequately in fresh water, failure to extract sufficient iodine from the iodine-poor Great Lakes, and a combination of these several possibilities.

  2. Density-dependent recruitment of the bloater (Coregonus hoyi) in Lake Michigan

    USGS Publications Warehouse

    Brown, Edward H.; Eck, Gary W.

    1992-01-01

    Density-dependent recruitment of the bloater (Coregonus hoyi) in Lake Michigan during and after recovery of the population in about 1977-1983 was best reflected in the fit of the Beverton-Holt recruitment function to age -1 and -2 recruits and estimated eggs of parents surveyed with trawls. A lower growth rate and lower lipid content of bloaters at higher population densities and no evidence of cannibalism supported the conclusion that recruitment is resource limited when alewife (Alosa pseudoharengus) abundance is low. Predation on larvae by alewives was indicated in earlier studies as the probable cause of depressed recruitment of bloaters before their recovery, which coincided with declining alewife abundance. This negative interaction masked any bloater stock-recruitment relation in the earlier period.

  3. Developmental changes in digestive enzyme activity in American shad, Alosa sapidissima, during early ontogeny.

    PubMed

    Gao, Xiao-Qiang; Liu, Zhi-Feng; Guan, Chang-Tao; Huang, Bin; Lei, Ji-Lin; Li, Juan; Guo, Zheng-Long; Wang, Yao-Hui; Hong, Lei

    2016-12-09

    In order to assess the digestive physiological capacity of the American shad Alosa sapidissima and to establish feeding protocols that match larval nutritional requirements, we investigated the ontogenesis of digestive enzymes (trypsin, amylase, lipase, pepsin, alkaline phosphatase, and leucine aminopeptidase) in larvae, from hatching to 45 days after hatching (DAH). We found that all of the target enzymes were present at hatching, except pepsin, which indicated an initial ability to digest nutrients and precocious digestive system development. Trypsin rapidly increased to a maximum at 14 DAH. Amylase sharply increased until 10 DAH and exhibited a second increase at 33 DAH, which coincided with the introduction of microdiet at 30 DAH, thereby suggesting that the increase was associated with the microdiet carbohydrate content. Lipase increased until 14 DAH, decreased until 27 DAH, and then increased until 45 DAH. Pepsin was first detected at 27 DAH and then sharply increased until 45 DAH, which suggested the formation of a functional stomach. Both alkaline phosphatase and leucine aminopeptidase markedly increased until 18 DAH, which indicated intestinal maturation. According to our results, we conclude that American shad larvae possess the functional digestive system before mouth opening, and the significant increases in lipase, amylase, pepsin, and intestinal enzyme activities between 27 and 33 DAH suggest that larvae can be successfully weaned onto microdiets around this age.

  4. The loss of hyperosmoregulatory ability in migrating juvenile American shad, Alosa sapidissima

    USGS Publications Warehouse

    Zydlewski, J.; McCormick, S.D.

    1997-01-01

    Investigations on juvenile American shad (Alosa sapidissima) revealed several physiological changes associated with downstream migration. Plasma chloride decreased 20% in wild juvenile shad during the autumn migration. Migrants had lower condition factor and hematocrit than non-migrant shad captured by beach seining. Gill Na+,K+-ATPase activity of migrant shad was higher than non-migrant; a 2.5-fold increase was observed in 1993, while a 57% increase was observed in 1994. Similar changes were observed in laboratory studies of shad maintained in fresh water under simulated natural temperature and photoperiod. Plasma chloride dropped 68% and gill Na+,K+-ATPase activity increased 3-fold over a 3-month period. Decreased plasma chloride was associated with increased mortality. Increases in gill Na+,K+-ATPase activity decreases in plasma chloride and osmolality, and incidence of mortality were delayed and moderated, but not eliminated, in shad maintained at constant temperature (24??C). Shad did not survive in fresh water past December regardless of temperature regime. In seawater, all shad survived and showed no perturbation of plasma chloride at 24??C or simulated natural temperature (above 4??C). The decline in hyperosmoregulatory ability, as influenced by declining temperatures, may serve as a proximate cue for autumnal migration.

  5. An integrative study of larval organogenesis of American shad Alosa sapidissima in histological aspects

    NASA Astrophysics Data System (ADS)

    Gao, Xiaoqiang; Hong, Lei; Liu, Zhifeng; Guo, Zhenglong; Wang, Yaohui; Lei, Jilin

    2016-01-01

    We describe organogenesis at a histological level in American shad ( Alosa sapidissima) larvae from 0 until 45 days after hatching (DAH). Larval development was divided into four stages based on the feeding mode, external morphological features, and structural changes in the organs: stage 1 (0-2 DAH), stage 2 (3-5 DAH), stage 3 (6-26 DAH) and stage 4 (27-45 DAH). At early stage 2 (3 DAH), American shad larvae developed the initial digestive and absorptive tissues, including the mouth and anal opening, buccopharyngeal cavity, oesophagus, incipient stomach, anterior and posterior intestine, differentiated hepatocytes, and exocrine pancreas. The digestive and absorptive capacity developed further in stages 2 to 3, at which time the pharyngeal teeth, taste buds, gut mucosa folds, differentiated stomach, and gastric glands could be observed. Four defined compartments were discernible in the heart at 4 DAH. From 3 to 13 DAH, the excretory systems started to develop, accompanied by urinary bladder opening, the appearance and development of primordial pronephros, and the proliferation and convolution of renal tubules. Primordial gills were detected at 2 DAH, the pseudobranch was visible at 6 DAH, and the filaments and lamellae proliferated rapidly during stage 3. The primordial swim bladder was first observed at 2 DAH and started to inflate at 9 DAH; from then on, it expanded constantly. The spleen was first observed at 8 DAH and the thymus was evident at 12 DAH. From stage 4 onwards, most organs essentially manifested an increase in size, number, and complexity of tissue structure.

  6. Histamine Formation in a Dry Salted Twaite Shad ( Alosa fallax lacustris ) Product.

    PubMed

    Vasconi, Mauro; Bellagamba, Federica; Bernardi, Cristian; Martino, Piera Anna; Moretti, Vittorio Maria

    2017-01-01

    Landlocked shad is a freshwater clupeid fish ( Alosa fallax lacustris ) whose consumption is associated with the risk of scombrotoxin poisoning. Traditionally, fresh shad are subjected to an artisanal processing procedure, consisting of dry salting and maturation under pressure, to give a fish product named missoltino , which is stored in large metallic barrels and is sold to local consumers and restaurants. In recent years, the introduction of modern food packaging technologies has enabled this product to also be distributed in shops and supermarkets. Consequently, the determination of the safety of this product is an urgent issue. The aims of the present research were to measure histamine levels and histamine-forming bacteria in shad products collected at different phases of preparation and ripening, in order to minimize poison hazards, to provide technical information about risk, and to standardize the production process. One hundred twenty-six samples of shad (21 fresh fish and 105 dried) at different phases of preparation and ripening were collected from seven producers and were analyzed for chemical composition, histamine content, and microbiological properties. After 130 days of ripening, samples from three producers presented unacceptable amounts of histamine (>200 mg/kg), according to European Union legislation. A moderate negative correlation was found between histamine levels and salt content (r =-0.504, P < 0.01) and between histamine levels and water phase salt content (r =-0.415, P < 0.01). Several bacterial strains that were positive on Niven's medium were isolated during the early phases of production, whereas the extreme environment of salted shad at the end of ripening led to a drastic decrease of bacteria, but not of histamine. The most effective preventive measures for histamine formation and accumulation in salted shad were strictly related to fish handling and storage conditions during processing.

  7. Metabolic rates in an anadromous clupeid, the American shad (Alosa sapidissima)

    USGS Publications Warehouse

    Leonard, J.B.K.; Norieka, J.F.; Kynard, B.; McCormick, S.D.

    1999-01-01

    To assess the energetics of migration in an anadromous fish, adult American shad (Alosa sapidissima) were swum in a large respirometer at a range of speeds (1.0–2.3 body lengths (BL) s−1, 13–24 °C). Metabolic rate (MO2) was logarithmically related to swimming speed (Bl s−1; r2 = 0.41, slope = 0.23 ± 0.037) and tailbeat frequency (beats × min−1; r2 = 0.52, slope = 0.003 ± 0.0003). Temperature had a significant effect on metabolic rate (r2 = 0.41) with a Q10of 2.2. Standard metabolic rate (SMR), determined directly after immobilization with the neuroblocker gallamine triethiodide, ranged from 2.2–6.2 mmolO2 kg−1 h−1 and scaled with mass (W) such that SMR = 4.0 (±0.03)W0.695(±0.15). Comparison of directly determined and extrapolated SMR suggests that swimming respirometry provides a good estimate of SMR in this species, given the differences in basal activity monitored by the two methods. Overall, American shad metabolic rates (MO2 and SMR) were intermediate between salmonids and fast-swimming perciforms, including tunas, and may be a result of evolutionary adaptation to their active pelagic, schooling life history. This study demonstrates variability in metabolic strategy among anadromous fishes that may be important to understanding the relative success of different migratory species under varying environmental conditions.

  8. Energy density and size of pelagic prey fishes in Lake Ontario, 1978-1990: Implications for salmonine energetics

    USGS Publications Warehouse

    Rand, Peter S.; Lantry, Brian F.; O'Gorman, R.; Owens, Randall W.; Stewart, Donald J.

    1994-01-01

    We describe dynamics of energy density and size of Lake Ontario alewife Alosa pseudoharengus and rainbow smelt Osmerus mordax, and we use a bioenergetics model of a common pelagic piscivore, chinook salmon Oncorhynchus tshawytscha, to demonstrate the effect of these factors on piscivore daily ration during 1978–1990. The energy density of alewives varied more than twofold between peaks in September (age 1) or October–November (age ≥2) and the lows in May (age 1) or July–September (age≥2). The previously described seasonal pattern of energy density of Lake Michigan alewives was similar except that energy density of older alewives (age≥3) was markedly higher in Lake Michigan. During 1978–1990, the spring energy density of Lake Ontario alewives peaked in 1979 (6,259 J/g wet weight), declined irregularly until 1985, and then remained stable through 1990 (at approximately 4,600 J/g). The initial decline may have been a density-dependent response to a burgeoning alewife population, but the lack of an increase in alewife condition in the late 1980s, when alewife biomass fell, suggests a decline in lake productivity. Energy density of rainbow smelt increased with age in Lake Ontario and condition was invariant during 1978–1990 despite a threefold change in rainbow smelt biomass. Rainbow smelt energy density was lower and fluctuated less seasonally in Lake Ontario than in Lake Michigan. Mean weight of alewives aged 2 and older dropped from 41 g in 1978 to 19 g in 1989 in Lake Ontario. Rainbow smelt aged 2 and older showed a drop in mean weight from 13–17 g in 1978–1982 to 8 g in 1990. This downward trend in mean size of alewives was correlated with the sizes of alewives consumed by Lake Ontario chinook salmon during 1983–1987. For adult chinook salmon to maintain a constant growth rate during 1978–1990, mean individual daily ration during June–October had to increase from a low of 2.2% body weight/d (or 1.5 prey fish/d) in 1979 to 3.1% body

  9. Migration behaviour of twaite shad Alosa fallax assessed by otolith Sr:Ca and Ba:Ca profiles.

    PubMed

    Magath, V; Marohn, L; Fietzke, J; Frische, M; Thiel, R; Dierking, J

    2013-06-01

    Individual migration behaviour during the juvenile and adult life phase of the anadromous twaite shad Alosa fallax in the Elbe estuary was examined using otolith Sr:Ca and Ba:Ca profiles. Between hatching and the end of the first year of life, juveniles showed two migration patterns. Pattern one exhibited a single downstream migration from fresh water to the sea with no return into fresh water. In contrast, pattern two showed a first migration into the sea, then a return into fresh water and, finally, a second downstream migration into marine water. This first report of migration plasticity for A. fallax points to different exposure times to estuarine threats depending on the migration strategy. In adults, high Sr:Ca and low Ba:Ca in the majority of individuals confirmed prior reports of a primarily marine habitat use. Patterns reflecting spawning migrations were rarely observed on otoliths, possibly due to the short duration of visits to fresh water.

  10. Diet of lake trout and burbot in northern Lake Michigan during spring: Evidence of ecological interaction

    USGS Publications Warehouse

    Jacobs, Gregory R.; Madenjian, Charles P.; Bunnell, David B.; Holuszko, Jeffrey D.

    2010-01-01

    We used analyses of burbot (Lota lota) and lake trout (Salvelinus namaycush) diets taken during spring gill-net surveys in northern Lake Michigan in 2006-2008 to investigate the potential for competition and predator-prey interactions between these two species. We also compared our results to historical data from 1932. During 2006-2008, lake trout diet consisted mainly of alewives (Alosa pseudoharengus) and rainbow smelt (Osmerus mordax), whereas burbot utilized a much wider prey base including round goby (Neogobius melanostomus), rainbow smelt, alewives, and sculpins. Using the Schoener's diet overlap index, we found a higher potential for interspecific competition in 1932 than in 2006-2008, though diet overlap was not significant in either time period. No evidence of cannibalism by lake trout or lake trout predation on burbot was found in either time period. In 2006-2008, however, lake trout composed 5.4% (by weight) of burbot diet. To determine whether this predation could be having an impact on lake trout rehabilitation efforts in northern Lake Michigan, we developed a bioenergetic-based consumption estimate for burbot on Boulder Reef (a representative reef within the Northern Refuge) and found that burbot alone can consume a considerable proportion of the yearling lake trout stocked annually, depending on burbot density. Overall, we conclude that predation, rather than competition, is the more important ecological interaction between burbot and lake trout, and burbot predation may be contributing to the failed lake trout rehabilitation efforts in Lake Michigan.

  11. A method for measuring total thiaminase activity in fish tissues

    USGS Publications Warehouse

    Zajicek, James L.; Tillitt, Donald E.; Honeyfield, Dale C.; Brown, Scott B.; Fitzsimons, John D.

    2005-01-01

    An accurate, quantitative, and rapid method for the measurement of thiaminase activity in fish samples is required to provide sufficient information to characterize the role of dietary thiaminase in the onset of thiamine deficiency in Great Lakes salmonines. A radiometric method that uses 14C-thiamine was optimized for substrate and co-substrate (nicotinic acid) concentrations, incubation time, and sample dilution. Total thiaminase activity was successfully determined in extracts of selected Great Lakes fishes and invertebrates. Samples included whole-body and selected tissues of forage fishes. Positive control material prepared from frozen alewives Alosa pseudoharengus collected in Lake Michigan enhanced the development and application of the method. The method allowed improved discrimination of thiaminolytic activity among forage fish species and their tissues. The temperature dependence of the thiaminase activity observed in crude extracts of Lake Michigan alewives followed a Q10 = 2 relationship for the 1-37??C temperature range, which is consistent with the bacterial-derived thiaminase I protein. ?? Copyright by the American Fisheries Society 2005.

  12. What is "fallback"?: metrics needed to assess telemetry tag effects on anadromous fish behavior

    USGS Publications Warehouse

    Frank, Holly J.; Mather, Martha E.; Smith, Joseph M.; Muth, Robert M.; Finn, John T.; McCormick, Stephen D.

    2009-01-01

    Telemetry has allowed researchers to document the upstream migrations of anadromous fish in freshwater. In many anadromous alosine telemetry studies, researchers use downstream movements (“fallback”) as a behavioral field bioassay for adverse tag effects. However, these downstream movements have not been uniformly reported or interpreted. We quantified movement trajectories of radio-tagged anadromous alewives (Alosa pseudoharengus) in the Ipswich River, Massachusetts (USA) and tested blood chemistry of tagged and untagged fish held 24 h. A diverse repertoire of movements was observed, which could be quantified using (a) direction of initial movements, (b) timing, and (c) characteristics of bouts of coupled upstream and downstream movements (e.g., direction, distance, duration, and speed). Because downstream movements of individual fish were almost always made in combination with upstream movements, these should be examined together. Several of the movement patterns described here could fall under the traditional definition of “fallback” but were not necessarily aberrant. Because superficially similar movements could have quite different interpretations, post-tagging trajectories need more precise definitions. The set of metrics we propose here will help quantify tag effects in the field, and provide the basis for a conceptual framework that helps define the complicated behaviors seen in telemetry studies on alewives and other fish in the field.

  13. Lakewide estimates of alewife biomass and Chinook salmon abundance and consumption in Lake Ontario, 1989–2005: implications for prey fish sustainability

    USGS Publications Warehouse

    Murry, Brent A.; Connerton, Michael J.; O'Gorman, Robert; Stewart, Donald J.; Ringlerd, Neil H.

    2010-01-01

    Stocking levels of Chinook salmon Oncorhynchus tshawytscha for Lake Ontario have been highly controversial since the early 1990s, largely because of uncertainties about lakewide abundance and rates of prey consumption. Previous estimates have focused on years before 1995; since then, however, the Lake Ontario ecosystem has undergone substantial changes, and there is new evidence of extensive natural recruitment. Presented here are new abundance estimates of Chinook salmon and alewives Alosa pseudoharengus in Lake Ontario and a reevaluation of the potential risk of alewife population collapse. We found that Lake Ontario has been supporting, on average (1989–2005), 1.83 × 106 (range, 1.08 × 106 to 3.24 × 106) Chinook salmon of ages 1–4, amounting to a mean annual biomass of 11.33 × 103 metric tons (range, 5.83 × 103 to 23.04 × 103 metric tons). During the same period (1989–2005), the lake supported an alewife biomass of 173.66 × 103 metric tons (range, 62.37 × 103 to 345.49 × 103 metric tons); Chinook salmon of ages 1–4 consumed, on average, 22% (range, 11–44%) of the alewife biomass annually. Because our estimates probably underestimate total consumption and because Chinook salmon are only one of several salmonine species that depend on alewives, predation pressure on the Lake Ontario alewife population may be high enough to raise concerns about long-term stability of this predator–prey system.

  14. Modeling migratory energetics of Connecticut River American shad (Alosa sapidissima): implications for the conservation of an iteroparous anadromous fish

    USGS Publications Warehouse

    Castro-Santos, Theodore; Letcher, Benjamin H.

    2010-01-01

    We present a simulation model in which individual adult migrant American shad (Alosa sapidissima) ascend the Connecticut River and spawn, and survivors return to the marine environment. Our approach synthesizes bioenergetics, reproductive biology, and behavior to estimate the effects of migratory distance and delays incurred at dams on spawning success and survival. We quantified both the magnitude of effects and the consequences of uncertainty in the estimates of input variables. Behavior, physiology, and energetics strongly affected both the distribution of spawning effort and survival to the marine environment. Delays to both upstream and downstream movements had dramatic effects on spawning success, determining total fecundity and spatial extent of spawning. Delays, combined with cues for migratory reversal, also determined the likelihood of survival. Spawning was concentrated in the immediate vicinity of dams and increased with greater migratory distance and delays to downstream migration. More research is needed on reproductive biology, behavior, energetics, and barrier effects to adequately understand the interplay of the various components of this model; it does provide a framework, however, that suggests that provision of upstream passage at dams in the absence of expeditious downstream passage may increase spawning success — but at the expense of reduced iteroparity. 

  15. Linking landscapes and habitat suitability scores for diadromous fish restoration in the susquehanna river basin

    USGS Publications Warehouse

    Kocovsky, P.M.; Ross, R.M.; Dropkin, D.S.; Campbell, J.M.

    2008-01-01

    Dams within the Susquehanna River drainage, Pennsylvania, are potential barriers to migration of diadromous fishes, and many are under consideration for removal to facilitate fish passage. To provide useful input for prioritizing dam removal, we examined relations between landscape-scale factors and habitat suitability indices (HSIs) for native diadromous species of the Susquehanna River. We used two different methods (U.S. Fish and Wildlife Service method: Stier and Crance [1985], Ross et al. [1993a, 1993b, 1997], and Pardue [1983]; Pennsylvania State University method: Carline et al. [1994]) to calculate HSIs for several life stages of American shad Alosa sapidissima, alewives Alosa pseudoharengus, and blueback herring Alosa aestivalis and a single HSI for American eels Anguilla rostrata based on habitat variables measured at transects spaced every 5 km on six major Susquehanna River tributaries. Using geographical information systems, we calculated land use and geologic variables upstream from each transect and associated those data with HSIs calculated at each transect. We then performed canonical correlation analysis to determine how HSIs were linked to geologic and land use factors. Canonical correlation analysis identified the proportion of watershed underlain by carbonate rock as a positive correlate of HSIs for all species and life stages except American eels and juvenile blueback herring. We hypothesize that potential mechanisms linking carbonate rock to habitat suitability include increased productivity and buffering capacity. No other consistent patterns of positive or negative correlation between landscape-scale factors and HSIs were evident. This analysis will be useful for prioritizing removal of dams in the Susquehanna River drainage, because it provides a broad perspective on relationships between habitat suitability for diadromous fishes and easily measured landscape factors. This approach can be applied elsewhere to elucidate relationships

  16. 78 FR 48943 - Endangered and Threatened Wildlife and Plants; Endangered Species Act Listing Determination for...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-08-12

    ...We, NMFS, have completed a comprehensive review of the status of river herring (alewife and blueback herring) in response to a petition submitted by the Natural Resources Defense Council (NRDC) requesting that we list alewife (Alosa pseudoharengus) and blueback herring (Alosa aestivalis) as threatened under the Endangered Species Act (ESA) throughout all or a significant portion of their range......

  17. Roles of predation, food, and temperature in structuring the epilimnetic zooplankton populations in Lake Ontario, 1981-1986

    USGS Publications Warehouse

    Johannsson, Ora E.; O'Gorman, Robert

    1991-01-01

    We sampled phytoplankton, zooplankton, and alewives Alosa pseudoharengus and measured water temperature in Lake Ontario during 1981–1986. Through the use of general linear regression models we then sought evidence of control of the eplimnetic zooplankton community (mid-July to mid-October) by producers, consumers, and temperature. Our measures of the zooplankton community were total biomass, cladoceran biomass, and the ratio of large to small Daphnia spp. (D. galeata mendotae andD. retrocurva). Zooplankton population variables assessed were abundance, egg ratio, and productivity. Through factor analysis, factors were created from the standardized, transformed independent variables for use in the regression analyses. Regression models showed significant inverse relationships (P < 0.05) between alewives and Bosmina longirostris (abundance, production, and egg ratio), Ceriodaphnia lacustris (egg ratio), andDaphnia retrocurva (egg ratio). Bosmina longirostris and D. retrocurva egg ratios were inversely related to algae biomass (<20 μm), thus the smaller algae might be controlled in part by the zooplankton community. Production of C. lacustris was directly related to temperature, as was the production and abundance of Tropocyclops prasinus. The annual size-frequency distributions of B. longirostris and D. retrocurva were inversely related to yearling alewife abundance and directly related to adult alewife abundance, which suggested that yearlings use a particulate-feeding mode on these zooplankton species more frequently than adults. We found no significant negative correlations among the zooplankton species, which suggested that interzooplankton predation and competition were not as important in structuring the community as were planktivory and temperature.

  18. Environmental and ecological conditions surrounding the production of large year classes of walleye (Sander vitreus) in Saginaw Bay, Lake Huron

    USGS Publications Warehouse

    Fielder, D.G.; Schaeffer, J.S.; Thomas, M.V.

    2007-01-01

    The Saginaw Bay walleye population (Sander vitreus) has not fully recovered from a collapse that began in the 1940s and has been dependent on stocking with only limited natural reproduction. Beginning in 2003, and through at least 2005, reproductive success of walleye surged to unprecedented levels. The increase was concurrent with ecological changes in Lake Huron and we sought to quantitatively model which factors most influenced this new dynamic. We developed Ricker stock-recruitment models for both wild and stock fish and evaluated them with second-order Akaike's information criterion to find the best model. Independent variables included adult alewife (Alosa pseudoharengus) abundance, spring water temperatures, chlorophyll a levels and total phosphorus levels. In all, 14 models were evaluated for production of wild age-0 walleyes and eight models for stocked age-0 walleyes. For wild walleyes, adult alewife abundance was the dominant factor, accounting for 58% of the variability in age-0 abundance. Production of wild age-0 fish increased when adult alewives were scarce. The only other plausible factor was spring water temperature. Predictably, alewife abundance was not important to stocked fish; instead temperature and adult walleye abundance were more significant variables. The surge in reproductive success for walleyes during 2003–2005 was most likely due to large declines in adult alewives in Lake Huron. While relatively strong year classes (age-1 and up) have been produced as a result of increased age-0 production during 2003–2005, the overall magnitude has not been as great as the initial age-0 abundance originally suggested. It appears that over-winter mortality is higher than in the past and may stem from higher predation or slower growth (lower condition for enduring winter thermal stress). From this it appears that low alewife abundance does not assure strong walleye year classes in Saginaw Bay but may be a prerequisite for them.

  19. Drying temperature effects on fish dry mass measurements

    USGS Publications Warehouse

    Lantry, B.F.; O'Gorman, R.

    2007-01-01

    Analysis of tissue composition in fish often requires dry samples. Time needed to dry fish decreases as temperature is increased, but additional volatile material may be lost. Effects of 10??C temperature increases on percentage dry mass (%DM) were tested against 60??C controls for groups of lake trout Salvelinus namaycush, rainbow smelt Osmerus mordax, slimy sculpin Cottus cognatus, and alewife Alosa pseudoharengus. Lake trout %DMs were lower at greater temperatures, but not significantly different from 60??C controls. Rainbow smelt and slimy sculpin %DMs were lower at greater temperatures and differences were significant when test temperatures reached 90??C. Significant differences were not found in tests using alewives because variability in %DM was high between fish. To avoid inter-fish variability, 30 alewives were each dried successively at 60, 70, 80, and then 90??C and for all fish %DM declined at each higher temperature. In general, %DMs were lower at greater temperatures and after reaching a stable dry weight, fish did not lose additional mass if temperature remained constant. Results indicate that caution should be used when comparing dry mass related indices from fish dried at different temperatures because %DM was negatively related to temperature. The differences in %DM observed with rising temperature could account for substantial portions of the variability in reported energy values for the species tested. Differences in %DM means for the 60 vs. 80??C and 60 vs. 90??C tests for rainbow smelt and alewife could represent of from 8 to 38% of observed annual energy cycles for Lakes Ontario and Michigan.

  20. Lipid concentrations in Lake Michigan fishes: Seasonal, spatial, ontogenetic, and long-term trends

    USGS Publications Warehouse

    Madenjian, Charles P.; Elliott, Robert F.; DeSorcie, Timothy J.; Stedman, Ralph M.; O'Connor, Daniel V.; Rottiers, Donald V.

    2000-01-01

    Lipid concentrations were measured in seven species of fish from several locations in Lake Michigan during spring, summer, and fall in 1994 to 1995. Adult alewife (Alosa pseudoharengus) and age-2 coho salmon (Oncorhynchus kisutch) exhibited pronounced seasonal changes in lipid content. Adult alewives averaged 7.4% lipid, on a wet weight basis, during spring (May), 2.6% in summer (July), and 12.2% in fall (late September through October). Spring lipid concentration was low in age-2 coho salmon, averaging only 1.9%, then increased to 7.8% during summer and decreased to 4.5% by fall. In contrast, lipid content in adult bloater (Coregonus hoyi) was relatively constant with respect to season, ranging between 10.6% and 12.4% during the year. Lipid concentration increased with fish size for all species except rainbow smelt (Osmerus mordax). Although deepwater sculpin (Myoxocephalus thompsoni) were considerably larger than slimy sculpin (Cottus cognatus) (mean total length of 117 mm vs 68 mm), mean lipid content of deepwater sculpin (7.6%) was only slightly higher than that for slimy sculpin (6.6%). Comparison of lipid concentrations from this study with previous studies indicated that lipid concentration in lake trout (Salvelinus namaycush) and alewives in Lake Michigan did not change significantly from 1969–1971 to 1994–1995. Lipid concentration in large (about 250 mm total length) adult bloaters near Saugatuck (along the southeastern shore of the lake) decreased from 23.3% in 1980 to 11.9% in 1986, but showed no significant change between 1986 and 1994–1995.

  1. Egg thiamine status of Lake Ontario salmonines 1995-2004 with emphasis on lake trout

    USGS Publications Warehouse

    Fitzsimons, J.D.; Williston, B.; Williston, G.; Brown, L.; El-Shaarawi, A.; Vandenbyllaardt, L.; Honeyfeld, D.; Tillitt, D.; Wolgamood, M.; Brown, S.B.

    2007-01-01

    Alewives (Alosa pseudoharengus), the major prey fish for Lake Ontario, contain thiaminase. They are associated with development of a thiamine deficiency in salmonines which greatly increases the potential for developing an early mortality syndrome (EMS). To assess the possible effects of thiamine deficiency on salmonine reproduction we measured egg thiamine concentrations for five species of Lake Ontario salmonines. From this we estimated the proportion of families susceptible to EMS based on whether they were below the ED20, the egg thiamine concentration associated with 20% mortality due to EMS. The ED20s were 1.52, 2.63, and 2.99 nmol/g egg for Chinook salmon (Oncorhynchus tshawytscha), lake trout (Salvelinus namaycush), and coho salmon (Oncorhynchus kisutch), respectively. Based on the proportion of fish having egg thiamine concentrations falling below the ED20, the risk of developing EMS in Lake Ontario was highest for lake trout, followed by coho (O. kisutch), and Chinook salmon, with the least risk for rainbow trout (O. mykiss). For lake trout from western Lake Ontario, mean egg thiamine concentration showed significant annual variability during 1994 to 2003, when the proportion of lake trout at risk of developing EMS based on ED20 ranged between 77 and 100%. Variation in the annual mean egg thiamine concentration for western Lake Ontario lake trout was positively related (p < 0.001, r2 = 0.94) with indices of annual adult alewife biomass. While suggesting the possible involvement of density-dependent changes in alewives, the changes are small relative to egg thiamine concentrations when alewife are not part of the diet and are of insufficient magnitude to allow for natural reproduction by lake trout.

  2. Proximate composition and caloric content of eight Lake Michigan fishes

    USGS Publications Warehouse

    Rottiers, Donald V.; Tucker, Robert M.

    1982-01-01

    We measured the proximate composition (percentage lipid, water, fat-free dry material, ash) and caloric content of eight species of Lake Michigan fish: lake trout (Salvelinus namaycush), coho salmon (Oncorhynchus kisutch), lake whitefish (Coregonus clupeaformis), bloater (Coregonus hoyi), alewife (Alosa pseudoharengus), rainbow smelt (Osmerus mordax), deepwater sculpin (Myoxocephalus quadricornis), and slimy sculpin (Cottus cognatus). Except for alewives, proximate composition and caloric content did not differ significantly between males and females. And, for coho salmon, there was no significant difference in composition between fish collected in different years. Lipid and caloric content of lake trout increased directly with age. In all species examined, lipids and caloric contents were significantly lower in small, presumably immature, fish than in larger, older fish. Lipid content of lake trout, lake whitefish, and bloaters (range of means, 16-22%) was nearly 3 times higher than that of coho salmon, sculpins, rainbow smelt, and alewives (range of means, 5.2-7.0%). The mean caloric content ranged from 6.9 to 7.1 kcal/g for species high in lipids and from 5.8 to 6.3 kcal/g for species low in lipids. Although the caloric content of all species varied directly with lipid content and inversely with water content, an increase in lipid content did not always coincide with a proportional increase in caloric content when other components of fish composition were essentially unchanged. This observation suggests that the energy content of fish estimated from the proximate composition by using universal conversion factors may not necessarily be accurate.

  3. Quantitative polymerase chain reaction (PCR) assays for a bacterial thiaminase I gene and the thiaminase-producing bacterium Paenibacillus thiaminolyticus.

    USGS Publications Warehouse

    Richter, C.A.; Wright-Osment, Maureen K.; Zajicek, J.L.; Honeyfield, D.C.; Tillitt, D.E.

    2009-01-01

    The thiaminase I enzyme produced by the gram-positive bacterium Paenibacillus thiaminolyticus isolated from the viscera of Lake Michigan alewives Alosa pseudoharengus is currently the only defined source of the thiaminase activity linked to thiamine (vitamin B1) deficiency in early mortality syndrome (EMS) in the larvae of Great Lakes salmonines. Diets of alewife or isolated strains of P. thiaminolyticus mixed in a semipurified diet and fed to lake trout Salvelinus namaycush have been shown to produce EMS in fry. We utilized quantitative polymerase chain reaction (Q-PCR) to aid in studies of the sources of P. thiaminolyticus and thiaminase I. Quantitative PCR assays were established to detect the thiaminase I gene of P. thiaminolyticus, the 16S rRNA gene from most species of bacteria, and the 16S rRNA gene specifically from P. thiaminolyticus and a few closely related taxa. The Q-PCR assays are linear over at least six orders of magnitude and can detect the thiaminase I gene of P. thiaminolyticus from as few as 1,000 P. thiaminolyticus cells/g of sample or the Paenibacillus 16S rRNA gene from as few as 100 P. thiaminolyticus cells/g of sample. The initial results from alewife viscera samples with high thiaminase activity yielded unexpectedly low densities of P. thiaminolyticus cells; Paenibacillus thiaminolyticus was detectable in 2 of 6 alewife viscera tested at densities on the order of 100 cells/g out of 100,000,000 total bacterial cells/g. The low numbers of P. thiaminolyticus detected suggest that alewives contain additional non-P. thiaminolyticus sources of thiaminase activity.

  4. Coupling age-structured stock assessment and fish bioenergetics models: a system of time-varying models for quantifying piscivory patterns during the rapid trophic shift in the main basin of Lake Huron

    USGS Publications Warehouse

    He, Ji X.; Bence, James R.; Madenjian, Charles P.; Pothoven, Steven A.; Dobiesz, Norine E.; Fielder, David G.; Johnson, James E.; Ebener, Mark P.; Cottrill, Adam R.; Mohr, Lloyd C.; Koproski, Scott R.

    2015-01-01

    We quantified piscivory patterns in the main basin of Lake Huron during 1984–2010 and found that the biomass transfer from prey fish to piscivores remained consistently high despite the rapid major trophic shift in the food webs. We coupled age-structured stock assessment models and fish bioenergetics models for lake trout (Salvelinus namaycush), Chinook salmon (Oncorhynchus tshawytscha), walleye (Sander vitreus), and lake whitefish (Coregonus clupeaformis). The model system also included time-varying parameters or variables of growth, length–mass relations, maturity schedules, energy density, and diets. These time-varying models reflected the dynamic connections that a fish cohort responded to year-to-year ecosystem changes at different ages and body sizes. We found that the ratio of annual predation by lake trout, Chinook salmon, and walleye combined with the biomass indices of age-1 and older alewives (Alosa pseudoharengus) and rainbow smelt (Osmerus mordax) increased more than tenfold during 1987–2010, and such increases in predation pressure were structured by relatively stable biomass of the three piscivores and stepwise declines in the biomass of alewives and rainbow smelt. The piscivore stability was supported by the use of alternative energy pathways and changes in relative composition of the three piscivores. In addition, lake whitefish became a new piscivore by feeding on round goby (Neogobius melanostomus). Their total fish consumption rivaled that of the other piscivores combined, although fish were still a modest proportion of their diet. Overall, the use of alternative energy pathways by piscivores allowed the increases in predation pressure on dominant diet species.

  5. Yield and dynamics of destabilized chub (Coregonus spp.) populations in Lakes Michigan and Huron, 1950-84

    USGS Publications Warehouse

    Brown, Edward H.; Argyle, Ray L.; Payne, N. Robert; Holey, Mark E.

    1987-01-01

    Deepwater ciscoes (Coregonus spp.) or 'chubs' of Lake Michigan far surpassed those of Lake Huron in yield, population density, and resilience following severe depletion in the 1960s and 1970s, when the bloater (C. hoyi) composed more than 90% of the stocks. The population decline of bloaters in recent decades was mainly attributed to exploitation, to the depression of chub recruitment (e.g. from inferred predation on early life stage) by nonendemic alewives (Alosa pseudoharengus) and rainbow smelt (Osmerus mordax), and to complications arising from extreme female predominance that was best documented for Lake Michigan. The various interactions between bloaters and the nonendemic species, which were intensified after the loss of large predators to sea lamprey (Petromyzon marinus), would help to explain why a stock-recruitment relation was not shown for the Lake Michigan bloater. We hypothesize that reproductive inefficiency caused by a shift to strong female predominance in the bloater depresses recruitment and thus helps to regulate abundance. However, the low resilience that sex imbalance seems to impart makes the stock unstable when exploited. It should therefore be exploited conservatively during such periods. Also, the sex ratio and its direction of change appear to be important qualifiers when surplus production is estimated from stock size.

  6. Evidence that sea lamprey control led to recovery of the burbot population in Lake Erie

    USGS Publications Warehouse

    Stapanian, M.A.; Madenjian, C.P.; Witzel, L.D.

    2006-01-01

    Between 1987 and 2003, the abundance of burbot Lota lota in eastern Lake Erie increased significantly, especially in Ontario waters. We considered four hypotheses to explain this increase: (1) reduced competition with lake trout Salvelinus namaycush, the other major coldwater piscivore in Lake Erie; (2) increased abundance of the two main prey species, rainbow smelt Osmerus mordax and round goby Neogobius melanostomus; (3) reduced interference with burbot reproduction by alewives Alosa pseudoharengus; and (4) reduced predation by sea lampreys Petromyzon marinus on burbot. Species abundance data did not support the first three hypotheses. Our results suggested that the apparent recovery of the burbot population of Lake Erie was driven by effective sea lamprey control. Sea lamprey predation appeared to be the common factor affecting burbot abundance in Lakes Michigan, Huron, Erie, and Ontario. In addition, relatively high alewife density probably depressed burbot abundance in Lakes Ontario and Michigan. We propose that a healthy adult lake trout population may augment burbot recovery in some lakes by serving as a buffer against sea lamprey predation and will not negatively impact burbot through competition.

  7. Records, ages, and growth of the mooneye, Hiodon tergisus, of the Great Lakes

    USGS Publications Warehouse

    Van Oosten, John

    1961-01-01

    Mooneyes (Hiodon tergisus) are very scarce in the upper three Great Lakes since only four specimens have been received from Lake Michigan, one from Lake Huron, and none from Lake Superior. The published statistics of the mooneyes are erroneous. Those of 1931 of Lake Michigan were perhaps chubs (Coregonus spp.) and those of Lake Huron of 1929 were also chubs and of 1934, 1949, and 1951 were gizzard shad (Dorosoma cepedianum) but since 1956 were alewives (Alosa pseudoharengus). Mooneyes are common in Lakes Erie and Ontario and perhaps in Lake St. Clair but are commercialized only in the States of Ohio and Michigan. Virtually all Lake Erie mooneyes were caught in trap nets, pound nets, and seines in less than 35 feet of water. Their life-history data collected in 1927-31 included lengths and weights of age-groups I-VII, calculated increments and lengths based on both anterior radii and lateral diameters of scales, length-weight relationships, and sexual maturity. Apparently mature specimens exceeded 8.8 inches, 3.25 ounces, and age-group I.

  8. Using larval fish abundance in the St. Clair and Detroit Rivers to predict year-class strength of forage fish in Lakes Huron and Erie

    USGS Publications Warehouse

    Hatcher, Charles O.; Nester, Robert T.; Muth, Kenneth M.

    1991-01-01

    Larval fish samples were collected in plankton tow nets in spring and summer, 1977–1978 and 1983–1984, in the St. Clair and Detroit rivers which are part of the connecting waterway between Lakes Huron and Erie. Larvae abundance of the major forage fish in the rivers are compared with their year-class abundance, as measured by bottom trawl catches of later life stages in Lakes Huron and Erie. Abundance of rainbow smelt, Osmerus mordax, and alewife, Alosa pseudo-harengus, larvae in the St. Clair River in adjacent years of the 4-year study was correlated with the abundance of yearlings captured in bottom trawls in lower Lake Huron in the spring of the following years. Abundance of locally produced larval rainbow smelt, alewives, and gizzard shad, Dorosoma cepedianum, in the Detroit River in adjacent years was correlated with the abundance oj’ young-of -t he-year captured in bottom trawls in western Lake Erie the following fall. Sampling fish larvae in the main channels of the St. Clair and Detroit rivers thus provided a potential early index of forage fish abundance in the lakes.

  9. Occurrence of the Great Lake's most recent invader, Hemimysis anomala, in the diet of fishes in southeastern Lake Ontario

    USGS Publications Warehouse

    Lantry, B.F.; Walsh, M.G.; Johnson, J.H.; McKenna, J.E.

    2010-01-01

    The Ponto-Caspian mysid, Hemimysis anomala, was first observed in southeastern Lake Ontario in May 2006. During July and August 2007, gill nets were fished in 6 to 8 m of water at two locations of known Hemimysis colonization in southeastern Lake Ontario to determine if fish that consume macroinvertebrates were beginning to include this new invasive mysid in their diets. Of nine fish species captured in August, September, and October 2007, three species had consumed Hemimysis: alewife (Alosa pseudoharengus), rock bass (Ambloplites rupestris), and yellow perch (Perca flavescens); and six species had not: round goby Apollonia melanostoma, smallmouth bass Micropterus dolomieu, spottail shiner Notropis hudsonius, gizzard shad Dorosoma cepedianum, white perch Morone americana and log perch Percina caprodes. Diets of alewives from all samples were composed predominantly of Hemimysis (69.6% -100% frequency of occurrence, 46.0%–74.5% dry weight diet composition). Two of 6 rock bass stomachs sampled in August contained ≥ 98.9% Hemimysis (10 and 40 individuals each) and one of 61 yellow perch stomachs sampled in September contained 10.0% Hemimysis (6 individuals) and 90.0% fish. While Hemimysis were observed only sparsely in the diet of most nearshore fish, their predominance in alewife diets and their omnivorous feeding behavior indicated that they have the potential to alter energy flow in Great Lakes' foodwebs.

  10. Increasing thiamine concentrations in lake trout eggs from Lakes Huron and Michigan coincide with low alewife abundance

    USGS Publications Warehouse

    Riley, Stephen C.; Rinchard, Jacques; Honeyfield, Dale C.; Evans, Allison N.; Begnoche, Linda

    2011-01-01

    Lake trout Salvelinus namaycush in the Laurentian Great Lakes suffer from thiamine deficiency as a result of adult lake trout consuming prey containing thiaminase, a thiamine-degrading enzyme. Sufficiently low egg thiamine concentrations result in direct mortality of or sublethal effects on newly hatched lake trout fry. To determine the prevalence and severity of low thiamine in lake trout eggs, we monitored thiamine concentrations in lake trout eggs from 15 sites in Lakes Huron and Michigan from 2001 to 2009. Lake trout egg thiamine concentrations at most sites in both lakes were initially low and increased over time at 11 of 15 sites, and the proportion of females with egg thiamine concentrations lower than the recommended management objective of 4 nmol/g decreased over time at eight sites. Egg thiamine concentrations at five of six sites in Lakes Huron and Michigan were significantly inversely related to site-specific estimates of mean abundance of alewives Alosa pseudoharengus, and successful natural reproduction of lake trout has been observed in Lake Huron since the alewife population crashed. These results support the hypothesis that low egg thiamine in Great Lakes lake trout is associated with increased alewife abundance and that low alewife abundance may currently be a prerequisite for successful reproduction by lake trout in the Great Lakes.

  11. Selective food preferences of walleyes of the 1959 year class in Lake Erie

    USGS Publications Warehouse

    Parsons, John W.

    1971-01-01

    Stomachs were examined from 1,473 walleyes (Stizostedion vitreum vitreum) of the 1959 year class collected in western Lake Erie from June 1959 to October 1960. In the same period, the relative abundance and lengths of potential forage species were determined from trawl catches. The walleye fed almost entirely on fish. In 1959 the food was dominated first (in June and July) by yellow perch (Perca flavescens) and then, in sequence, by spottail shiners (Notropis hudsonius) and emerald shiners (Notropis atherinoides). In 1960, the walleyes fed mostly on yearling spottail shiners and emerald shiners in the spring and summer but young alewives (Alosa pseudoharengus) became the dominant food in the fall. The length of forage fish increased with the length of walleyes and walleyes of a given length usually ate forage fish within a restricted range of lengths. This size preference was shown by walleyes of the same length in the same and different months. The increased in length of forage fish with length of walleye was not proportionate. Walleyes 2.5 inches long ate forage fish 0.44 times their length whereas walleyes 15.5 inches long ate forage fish only 0.28 times their length. The diet of the walleyes changed according to species and lengths of forage fish available. Since young of several species hatched in different months and grew at different rates, abundance and suitability as forage sometimes changed rapidly.

  12. Resurgence of emerald shiners Notropis atherinoides in Lake Huron's main basin

    USGS Publications Warehouse

    Schaeffer, J.S.; Warner, D.M.; O'Brien, T. P.

    2008-01-01

    Emerald shiners Notropis atherinoides were formerly common in Lakes Huron and Michigan, but declined during the 1960s as the exotic alewife Alosa pseudoharengus proliferated. The Lake Huron emerald shiner population was chronically depressed through 2004; however, we detected resurgence in emerald shiner density and biomass in Lake Huron during acoustic and midwater trawl surveys conducted during 2004-2006. Emerald shiners were not found during 2004, but by 2006 main basin density exceeded 500 fish/ha, biomass estimates exceeded 0.5 kg/ha, and emerald shiners contributed more to pelagic biomass than alewives or rainbow smelt Osmerus mordax. Length frequency distributions suggested that increased density was the result of two consecutive strong year classes in 2005 and 2006. Emerald shiner distributions also expanded from a focus in western Lake Huron in 2005 to a lakewide distribution in 2006. Emerald shiners occurred offshore, but were nearly always associated with epilimnetic surface waters warmer than 19??C. Resurgence of emerald shiners was likely a consequence of reduced alewife abundance, as they declined concurrently with alewife proliferation during the early 1960s. Return of this species may benefit native nearshore piscivores; however, benefits to Pacific salmonids Oncorhynchus spp. are uncertain because emerald shiners are smaller and still less abundant than historically important prey species, and they may be thermally segregated from salmonines.

  13. Transcriptomic imprints of adaptation to fresh water: parallel evolution of osmoregulatory gene expression in the Alewife.

    PubMed

    Velotta, Jonathan P; Wegrzyn, Jill L; Ginzburg, Samuel; Kang, Lin; Czesny, Sergiusz; O'Neill, Rachel J; McCormick, Stephen D; Michalak, Pawel; Schultz, Eric T

    2017-02-01

    Comparative approaches in physiological genomics offer an opportunity to understand the functional importance of genes involved in niche exploitation. We used populations of Alewife (Alosa pseudoharengus) to explore the transcriptional mechanisms that underlie adaptation to fresh water. Ancestrally anadromous Alewives have recently formed multiple, independently derived, landlocked populations, which exhibit reduced tolerance of saltwater and enhanced tolerance of fresh water. Using RNA-seq, we compared transcriptional responses of an anadromous Alewife population to two landlocked populations after acclimation to fresh (0 ppt) and saltwater (35 ppt). Our results suggest that the gill transcriptome has evolved in primarily discordant ways between independent landlocked populations and their anadromous ancestor. By contrast, evolved shifts in the transcription of a small suite of well-characterized osmoregulatory genes exhibited a strong degree of parallelism. In particular, transcription of genes that regulate gill ion exchange has diverged in accordance with functional predictions: freshwater ion-uptake genes (most notably, the 'freshwater paralog' of Na(+) /K(+) -ATPase α-subunit) were more highly expressed in landlocked forms, whereas genes that regulate saltwater ion secretion (e.g. the 'saltwater paralog' of NKAα) exhibited a blunted response to saltwater. Parallel divergence of ion transport gene expression is associated with shifts in salinity tolerance limits among landlocked forms, suggesting that changes to the gill's transcriptional response to salinity facilitate freshwater adaptation.

  14. Diel and seasonal distribution patterns of eggs, embryos and larvae of Twaite shad Alosa fallax fallax (Lacépède, 1803) in a lowland tidal river

    NASA Astrophysics Data System (ADS)

    Esteves, Eduardo; Pedro Andrade, José

    2008-09-01

    The anadromous Twaite shad Alosa fallax fallax (Lacépède, 1803) is globally classified as "Data Deficient" by the IUCN but the Instituto de Conservação da Natureza, Portugal, classified the species as "Vulnerable". In this study, the aims were to describe the putative diel, seasonal and inter-annual patterns of distribution and abundance of Twaite shad early life-history stages in a lowland tidal river, River Mira (south Portugal), and to examine how changes in temperature, rainfall, microplankton biomass, potential prey and competitors' predator abundance affect the distribution patterns using generalised additive models (GAM). Twaite shad yolk-sac larvae were collected indiscriminately at various times of day while larvae were more common during daylight hours in comparison to samples collected during the night, independently of tide. Moreover, A. f. fallax eggs, embryos and larvae were found in samples from late-March to mid-June. Peak densities were observed around late-April for eggs, mid-May for embryos and mid to late-May for larvae. The observed among- and within-year changes in abundance of Twaite shad embryos and larvae were related, through GAM, with a combination of environmental covariates, mainly in a non-linear way.

  15. Climate change and the green energy paradox: the consequences for twaite shad Alosa fallax from the River Severn, U.K.

    PubMed

    Aprahamian, M W; Aprahamian, C D; Knights, A M

    2010-11-01

    A stock-recruitment model with a temperature component was used to estimate the effect of an increase in temperature predicted by climate change projections on population persistence and distribution of twaite shad Alosa fallax. An increase of 1 and 2° C above the current mean summer (June to August) water temperature of 17·8° C was estimated to result in a three and six-fold increase in the population, respectively. Climate change is also predicted to result in an earlier commencement to their spawning migration into fresh water. The model was expanded to investigate the effect of any additional mortality that might arise from a tidal power barrage across the Severn Estuary. Turbine mortality was separated into two components: (1) juvenile (pre-maturation) on their out migration during their first year and on their first return to the river to spawn and (2) post-maturation mortality on adults on the repeat spawning component of the population. Under current conditions, decreasing pre-maturation and post-maturation survival by 8% is estimated to result in the stock becoming extinct. It is estimated that an increase in mean summer water temperature of 1° C would mean that survival pre and post-maturation would need to be reduced by c. 10% before the stock becomes extinct. Therefore, climate change is likely to be beneficial to populations of A. fallax within U.K. rivers, increasing survival and thus, population persistence.

  16. Application of theory and research in fishery management of the Laurentian Great Lakes

    USGS Publications Warehouse

    Smith, Stanford H.

    1973-01-01

    Three examples are used to illustrate these problems: (1) Sea lamprey (Petromyzon marinus) research was not initiated until 50 years after the destructiveness of the sea lamprey was recognized, and control measures were not developed or applied until species most vulnerable to the lamprey had been greatly reduced or eliminated. (2) Most research on the alewife (Alosa pseudoharengus) has been directed toward determining why large numbers of alewives die during the spring and summer, but has not provided the information most urgently needed by management to use alewives to best advantage, or to reduce the biological or human problems that alewives cause. (3) After a study during 1926-30 to determine if pollution was affecting fish in Lake Erie, it was concluded that the detrimental effects of pollution in certain regions were offset by the benefits of enrichment in other areas, but managers were not warned that areas of pollution might expand, and eventually influence the entire lake. The Great Lakes ecosystem is complex and in a state of rapid change. Thus, the outcome from the application of theory is uncertain at best and there can be no assurance that the desired results will be attained. The programs for sea lamprey control and salmonid restoration are a current example of difficulty in application of theory in management. Superficially the sea lamprey appears to be under control and salmonids have been restored. The postcontrol abundance of sea lampreys, however, is equal to the abundance that caused the initial collapse of the lake trout (Salvelinus namaycush), and there is evidence that the damage lampreys are inflicting on lake trout is as heavy as it was in the precontrol period. Also, in the presence of an abundance of hatchery-reared salmonids, the lamprey is reproducing and thriving as well as or better than it did during its initial population explosion, and indications are that it will increase rather than decrease under the present method and level of

  17. Increase in lake trout reproduction in lake huron following the collapse of alewife: Relief from thiamine deficiency or larval predation?

    USGS Publications Warehouse

    Fitzsimons, J.D.; Brown, S.; Brown, L.; Honeyfield, D.; He, J.; Johnson, J.E.

    2010-01-01

    In the Great Lakes there is still uncertainty as to the population level effects of a thiamine deficiency on salmonines caused by high consumption of alewives Alosa pseudoharengus. A resurgence of lake trout Salvelinus namaycush reproduction in Lake Huron following the crash of alewife stocks between 2002 and 2004 provided an opportunity to evaluate the relative effects of this crash on reproduction through relief from either alewife mediated thiamine deficiency or alewife predation on larval lake trout relative to possible changes in the size of the lake trout spawning stock. Changes in mean lake trout egg thiamine concentration post crash at one spawning reef in Parry Sound, wheremean thiamine concentration increased by almost two fold, were consistent with diet switching from alewives to rainbow smelt Osmerus mordax, the next most abundant prey fish in Lake Huron. Although thiamine levels for lake trout collected at a second reef in Parry Sound did not change post-crash, levels both pre- and post-crash were consistent with a rainbow smelt diet. A reef specific fry emergence index was found to be positively related to reef specific egg thiamine concentration but negatively related to reef specific occurrence of EMS, a thiamine deficiency related mortality syndrome. We found little evidence for overlap between the timing of spring shoreward migration of alewives and lake trout emergence, suggesting that relief from alewife predation effects had relatively little effect on the observed increase in lake trout recruitment. Numbers of spawners in the north, north-central, and southern zones of the lake increased from 2000 onwards. Overall the abundance post-2003 was higher than from pre-2004, suggesting that spawner abundance may also have contributed to increased lake trout reproduction. However, predicted numbers of spawners and measured abundance of wild recruits in assessment gear were poorly correlated suggesting that the increase in reproduction was not totally

  18. Effects of different salinities on growth performance, survival, digestive enzyme activity, immune response, and muscle fatty acid composition in juvenile American shad (Alosa sapidissima).

    PubMed

    Liu, Zhi-Feng; Gao, Xiao-Qiang; Yu, Jiu-Xiang; Qian, Xiao-Ming; Xue, Guo-Ping; Zhang, Qiao-Yun; Liu, Bao-Liang; Hong, Lei

    2016-12-24

    The effects of salinity on survival, growth, special activity of digestive enzymes, nonspecific immune response, and muscle fatty acid composition were evaluated in the American shad (Alosa sapidissima). Juveniles of 35 days after hatching were reared at 0 (control), 7, 14, 21, and 28 ppt for 60 days. At the end of the experiment, juvenile American shad presented higher survival and specific growth rate (SGR) in salinity group (7, 14, and 21 ppt) than control group (P < 0.05). The special activity of trypsin and chymotrypsin was highest in fish reared at 21 ppt, while the highest lipase special activity was obtained in control group (P < 0.05). The special activity of alkaline phosphatase (ALP), lysozyme (LZM), superoxide dismutase (SOD), and catalase (CAT) showed significant increases in salinity group (14 and 21 ppt) compared to control group (P < 0.05). Lower muscle ash contents were detected in salinity group (14, 21, and 28 ppt) than control group (P < 0.05), while the contents of crude lipid and crude protein were significantly higher than control group (P < 0.05). The level of monounsaturated fatty acids (MUFA) exhibited a decreasing trend, while an increased level of polyunsaturated fatty acids (PUFA) was detected with the increase of salinity. Among the PUFA, the content of n-3 fatty acids in muscle tissue was found to be increasing with the increasing salinity, especially eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA). Results indicate that appropriate increase in salinity was reasonable and beneficial for juvenile American shad culture after a comprehensive consideration, especially salinity range from 14 to 21 ppt.

  19. Gut content analysis of Lake Michigan waterbirds in years with avian botulism type E mortality, 2010–2012

    USGS Publications Warehouse

    Essian, David A.; Chipault, Jennifer G.; Lafrancois, Brenda M.; Leonard, Jill B.K.

    2016-01-01

    Waterbird die-offs caused by Clostridium botulinum neurotoxin type E (BoNT/E) have occurred sporadically in the Great Lakes since the late 1960s, with a recent pulse starting in the late 1990s. In recent die-offs, round gobies (Neogobius melanostomus) have been implicated as vectors for the transfer of BoNT/E to fish-eating birds due to the round goby invasion history and their importance as prey. Dreissenid mussels (Dreissena spp.) are also potentially involved in BoNT/E transmission to birds and round gobies. We examined gut contents of waterbirds collected in Lake Michigan during die-offs in 2010–2012, and the gut contents of culled, presumably BoNT/E-free double-crested cormorants (Phalacrocorax auritus). Round gobies were found in 86% of the BoNT/E-positive individuals, 84% of the BoNT/E-negative birds, and 94% of the BoNT/E-free cormorants examined. Double-crested cormorants, ring-billed gulls (Larus delewarensis), and common loons (Gavia immer) consumed larger-sized round gobies than horned and red-necked grebes (Podiceps auritus and Podiceps grisegena), white-winged scoters (Melanitta deglandi), and long-tailed ducks (Clangula hymealis). Other common prey included dreissenid mussels, terrestrial insects, and alewives (Alosa pseudoharengus). Our data emphasize the importance of round gobies and mussels in diets of Lake Michigan waterbirds and suggest they may play a role in the transfer of BoNT/E to waterbirds; however, round gobies and mussels were found in BoNT/E-positive, -negative, and -free individuals, suggesting that other factors, such as alternative trophic pathways for toxin transfer, bird migratory timing and feeding locations, prey behavior, and individual physiological differences across birds may affect the likelihood that a bird will succumb to BoNT/E intoxication.

  20. Changes in the Lake Michigan food web following dreissenid mussel invasions: A synthesis

    USGS Publications Warehouse

    Madenjian, Charles P.; Bunnell, David B.; Warner, David M.; Pothoven, Steven A.; Fahnenstiel, Gary L.; Nalepa, Thomas F.; Vanderploeg, Henry A.; Tsehaye, Iyob; Claramunt, Randall M.; Clark, Richard D

    2015-01-01

    Using various available time series for Lake Michigan, we examined changes in the Lake Michigan food web following the dreissenid mussel invasions and identified those changes most likely attributable to these invasions, thereby providing a synthesis. Expansion of the quagga mussel (Dreissena rostriformis bugensis) population into deeper waters, which began around 2004, appeared to have a substantial predatory effect on both phytoplankton abundance and primary production, with annual primary production in offshore (> 50 m deep) waters being reduced by about 35% by 2007. Primary production likely decreased in nearshore waters as well, primarily due to predatory effects exerted by the quagga mussel expansion. The drastic decline inDiporeia abundance in Lake Michigan during the 1990s and 2000s has been attributed to dreissenid mussel effects, but the exact mechanism by which the mussels were negatively affecting Diporeia abundance remains unknown. In turn, decreased Diporeiaabundance was associated with reduced condition, growth, and/or energy density in alewife (Alosa pseudoharengus), lake whitefish (Coregonus clupeaformis), deepwater sculpin (Myoxocephalus thompsonii), and bloater (Coregonus hoyi). However, lake-wide biomass of salmonines, top predators in the food web, remained high during the 2000s, and consumption of alewives by salmonines actually increased between the 1980–1995 and 1996–2011 time periods. Moreover, abundance of the lake whitefish population, which supports Lake Michigan's most valuable commercial fishery, remained at historically high levels during the 2000s. Apparently, counterbalancing mechanisms operating within the complex Lake Michigan food web have enabled salmonines and lake whitefish to retain relatively high abundances despite reduced primary production.

  1. Potential impacts of water diversion on fishery resources in the Great Lakes

    USGS Publications Warehouse

    Manny, Bruce A.

    1984-01-01

    Uses of Great Lakes water within the Great Lakes basin are steadily increasing, and critical water shortages elsewhere may add to the demands for diversions of water out of the basin in the near future. The impacts of such diversions on fish in the Great Lakes must be considered in the context of in-basin uses of the water, because in-basin uses already adversely affect the fishery resources. Temporary in-basin water withdrawals from Lake Michigan by industry in 1980 equaled 260% of the total volume of water between the shoreline and the 10-meter depth - the littoral waters most heavily used by fish as spawning and nursery grounds. Nearly 100% of the fish removed by these water withdrawals were killed. Enough young alewives (Alosa pseudoharengus) and rainbow smelt (Osmerus mordax) in Lake Michigan and young yellow perch (Perca flavescens) in western Lake Erie have been removed at water intakes in recent years to reduce the productivity and biomass of adult fish stocks. Out-of-basin diversions of water at Chicago and at the Welland Canal, channel modifications in the St. Clair River, and in-basin consumptive water withdrawals have lowered the annual mean water level of Lakes Michigan and Huron by about 27 cm and that of Lake Erie by about 10 cm, dewatering wetlands that historically served as spawning and nursery habitat for many valuable fish species. The dollar value of fish lost to water diversions and withdrawals has not yet been estimated, but water withdrawals alone have already reduced the annual economic impact of the Great Lakes fisheries, which has been estimated to be 1.16 billion dollars.

  2. Effectiveness and retention of thiamine and its analogs administered to steelhead and landlocked Atlantic salmon

    USGS Publications Warehouse

    Ketola, H.G.; Isaacs, G.R.; Robins, J.S.; Lloyd, R.C.

    2008-01-01

    We investigated the feasibility of enhancing the reproduction of steelhead Oncorhynchus mykiss and landlocked Atlantic salmon Salmo salar in lakes where the consumption of alewives Alosa pseudoharengus and other forage fishes containing thiaminase can cause them to become thiamine deficient and thereby reduce the survival of their fry. We evaluated feeding fingerling steelhead excess thiamine hydrochloride (THCl) for 1 or 2 weeks or equimolar amounts of thiamine mononitrate, thiamine-tetrahydrofurfuryl-disulfide, benfotiamine, or dibenzoyl thiamine (DBT). We found minimal internal reserves of thiamine after 6 months. We also compared the ability of injections of thiamine and its analogs to prevent mortality in thiamine-deficient steelhead and Atlantic salmon sac fry and found all forms to be effective, although benfotiamine was the least effective on an equimolar basis. Further, we injected yearling steelhead and found that DBT was tolerated at approximately 11,200 nmol/g of body weight, about 10 times more than thiamine in any other form. When yearling steelhead were injected with near-maximal doses of thiamine hydrochloride and several analogs and then fed a thiamine-deficient diet, DBT was retained for approximately 2 years - in contrast to other forms, which were retained for less than about 6 months. Therefore, these results suggest that neither feeding nor injecting young hatchery salmonids with DBT is likely to enhance their reproduction for more than 2 years after stocking. However, injecting DBT in nearly mature fish (either cultured fish from hatcheries or wild fish captured in lakes) may provide them with enough thiamine to successfully spawn within 2 years even though they consume mainly thiaminase-containing forage fishes. ?? Copyright by the American Fisheries Society 2008.

  3. Effects of thiamine on reproduction of Atlantic salmon and a new hypothesis for their extirpation in Lake Ontario

    USGS Publications Warehouse

    Ketola, H. George; Bowser, Paul R.; Wooster, Gregory A.; Wedge, Leslie R.; Hurst, Steven S.

    2000-01-01

    Previous researchers demonstrated that a mortality in fry (called Cayuga syndrome) of Atlantic salmon Salmo salar from Cayuga Lake (New York) was associated with low levels of thiamine. They reduced the mortality of fry by bathing or injecting fry with thiamine. We injected four to six gravid female Atlantic salmon with either physiological saline (PS) or PS plus thiamine (7 mg/kg weight) 14–23 d before eggs were stripped, fertilized, and incubated in individual lots. Chemical analyses showed that eggs from control and treated salmon contained 1.1 and 1.6 nmol thiamine/g, respectively. Thiamine injections had no significant effect on the percentage of eggs that hatched. Between 700 and 800 Celius degree-days postfertilization, control fry (saline) showed signs of Cayuga syndrome and a 45% incidence of mortality; in contrast, mortality was only 1.9% for fry that received thiamine. By 1,078 degree-days postfertilization, mean mortality of control fry was 98.6%, whereas that for thiamine-injected salmon was 2.1%. This study showed that thiamine injections of prespawning female salmon from Cayuga Lake increased thiamine content of their eggs and prevented the Cayuga syndrome and subsequent mortality of fry. Historically, overfishing, pollution, and building of dams and barriers to spawning migration were suggested as possible causes of the decline of the Atlantic salmon in Lake Ontario and Cayuga Lake. Based on our findings and other reports, we suggest another possible contributing cause of the extirpation of landlocked Atlantic salmon in Lake Ontario and some other inland waters of New York: The entrance of alewives Alosa pseudoharengus containing thiaminase, which induced thiamine deficiency in eggs and increased mortality in fry of the predatory salmon.

  4. Comparative bioenergetics modeling of two Lake Trout morphotypes

    USGS Publications Warehouse

    Kepler, Megan V.; Wagner, Tyler; Sweka, John A.

    2014-01-01

    Efforts to restore Lake Trout Salvelinus namaycush in the Laurentian Great Lakes have been hampered for decades by several factors, including overfishing and invasive species (e.g., parasitism by Sea Lampreys Petromyzon marinus and reproductive deficiencies associated with consumption of Alewives Alosa pseudoharengus). Restoration efforts are complicated by the presence of multiple body forms (i.e., morphotypes) of Lake Trout that differ in habitat utilization, prey consumption, lipid storage, and spawning preferences. Bioenergetics models constitute one tool that is used to help inform management and restoration decisions; however, bioenergetic differences among morphotypes have not been evaluated. The goal of this research was to investigate bioenergetic differences between two actively stocked morphotypes: lean and humper Lake Trout. We measured consumption and respiration rates across a wide range of temperatures (4–22°C) and size-classes (5–100 g) to develop bioenergetics models for juvenile Lake Trout. Bayesian estimation was used so that uncertainty could be propagated through final growth predictions. Differences between morphotypes were minimal, but when present, the differences were temperature and weight dependent. Basal respiration did not differ between morphotypes at any temperature or size-class. When growth and consumption differed between morphotypes, the differences were not consistent across the size ranges tested. Management scenarios utilizing the temperatures presently found in the Great Lakes (e.g., predicted growth at an average temperature of 11.7°C and 14.4°C during a 30-d period) demonstrated no difference in growth between the two morphotypes. Due to a lack of consistent differences between lean and humper Lake Trout, we developed a model that combined data from both morphotypes. The combined model yielded results similar to those of the morphotype-specific models, suggesting that accounting for morphotype differences may

  5. Thiamine and thiaminase status in forage fish of salmonines from Lake Michigan

    USGS Publications Warehouse

    Tillitt, D.E.; Zajicek, J.L.; Brown, S.B.; Brown, L.R.; Fitzsimons, J.D.; Honeyfield, D.C.; Holey, M.E.; Wright, G.M.

    2005-01-01

    Dietary sources of thiamine (vitamin B1) and thiamine-degrading enzymes (thiaminases) are thought to be primary factors in the development of thiamine deficiency among Great Lakes salmonines. We surveyed major forage fish species in Lake Michigan for their content of thiamine, thiamine vitamers, and thiaminase activity. Concentrations of total thiamine were similar (P ≤ 0.05) among most forage fishes (alewife Alosa pseudoharengus, bloater Coregonus hoyi, spottail shiner Notropis hudsonius, deepwater sculpin Myoxocephalus thompsonii, yellow perch Perca flavescens, ninespine stickleback Pungitius pungitius, and round goby Neogobius melanostomus) and slightly lower in rainbow smelt Osmerus mordax. Concentrations of total thiamine were all above the dietary requirements of coldwater fishes, suggesting the thiamine content of forage fish is not the critical factor in the development of thiamine deficiency in Lake Michigan salmonines. Thiamine pyrophosphate was the predominant form of thiamine in most species of forage fish, followed by free thiamine and thiamine monophosphate. Total thiamine was slightly greater in summer collections of alewife and rainbow smelt than in spring and fall collections, but the same was not true for bloater. Thiaminase activity varied among species and was greatest in gizzard shad Dorosoma cepedianum, spottail shiner, alewife, and rainbow smelt. Thiaminase activity in alewife varied among collection locations, season (greatest in spring), and size of the fish. Size and condition factors were positively correlated with both total thiamine and thiaminase activity in alewife. Thus, thiamine and thiaminase activity in forage fishes collected in Lake Michigan varied among species, seasons, year caught, and size (or condition). Therefore, multiple factors must be considered in the development of predictive models for the onset of thiamine deficiency in Great Lakes salmonines. Most importantly, thiaminase activity was great in alewives and

  6. Ontogenic and spatial patterns in diet and growth of lake trout in Lake Michigan

    USGS Publications Warehouse

    Madenjian, Charles P.; DeSorcie, Timothy J.; Stedman, Ralph M.

    1998-01-01

    Lake trout Salvelinus namaycush in nearshore waters of Lake Michigan grow faster than lake trout residing offshore on Sheboygan Reef, which is in midlake. We examined the stomachs of lake trout, spanning ages 1 through 16, caught in both nearshore and offshore environments of Lake Michigan during 1994 and 1995 to determine whether diet differences may be responsible for the difference in growth rate. A comparison of the diets, coupled with bioenergetics modeling, indicated that juvenile lake trout on Sheboygan Reef experienced slow growth due to low food availability rather than to cold water temperatures. The availability of appropriate-size prey appeared to regulate lake trout growth. Small prey fish were probably not readily available to small (200- to 399-mm total length) lake trout on Sheboygan Reef, a substantial portion of whose diet consisted of invertebrates; in contrast, nearshore juveniles had a nearly 100% fish diet. Growth rate on the reef remained slow through intermediate lake trout sizes (400-599 mm total length), presumably due to low availability of rainbow smelt Osmerus mordax on the reef. Once lake trout achieved total lengths of approximately 600 mm, they grew slightly faster on Sheboygan Reef than near shore, indicating that large (>170-mm total length) prey fish were readily available to lake trout in the reef area. On a wet-weight basis, alewife Alosa pseudoharengus dominated the diet of large (a?Y 600 mm total length) lake trout from both the nearshore and offshore regions of the lake, although bloater Coregonus hoyi composed over 30% of the diet on Sheboygan Reef and in southeastern nearshore Lake Michigan. Size of alewife prey increased with lake trout size. The bloater population currently represents the bulk of the biomass of the adult prey fish community, so our diet analysis suggests that large lake trout are continuing to select alewives.

  7. Optimum temperature for growth and preferred temperatures of age-0 lake trout

    USGS Publications Warehouse

    Edsall, Thomas A.; Cleland, Joshua

    2000-01-01

    This study was performed to determine the thermal preferences and optimum temperature for growth of age-0 lake trout Salvelinus namaycush to help predict the thermal habitat they select when they leave the spawning grounds and to assess the risk posed to them in the Great Lakes by piscivorus, nonnative fishes whose thermal habitat preferences are known. The test fish were hatched in the laboratory from eggs taken from wild fish, acclimated to 5, 10, 15, and 18°C, and fed to excess with commercial trout food for 47 d. The test fish grew at all of the temperatures, and the specific growth rate was highest at about 12.5°C (3.8% wet body weight/d). Fish used in the growth study were also tested in a vertical thermal gradient tank and had a final thermal preferendum between 10.1°C and 10.2°C. These results, which generally agreed with those of an earlier laboratory study of the temperature preference of age-1 lake trout and the limited information on thermal habitat use by age-0 lake trout in the Great Lakes, indicated age-0 lake trout would tend to seek temperatures near 10°C, or as high as 12.5°C, during summer if food was abundant. Published information on thermal habitat use of age-1 and adult alewives Alosa pseudoharengus and rainbow smelt Osmerus mordax indicated they would be expected to co-occur with age-0 lake trout during much of the time when the lake trout were small enough to be eaten by these two introduced piscivores.

  8. The effect of thiamine injection on upstream migration, survival, and thiamine status of putative thiamine-deficient coho salmon

    USGS Publications Warehouse

    Fitzsimons, J.D.; Williston, B.; Amcoff, P.; Balk, L.; Pecor, C.; Ketola, H.G.; Hinterkopf, J.P.; Honeyfield, D.C.

    2005-01-01

    A diet containing a high proportion of alewives Alosa pseudoharengus results in a thiamine deficiency that has been associated with high larval salmonid mortality, known as early mortality syndrome (EMS), but relatively little is known about the effects of the deficiency on adults. Using thiamine injection (50 mg thiamine/kg body weight) of ascending adult female coho salmon Oncorhynchus kisutch on the Platte River, Michigan, we investigated the effects of thiamine supplementation on migration, adult survival, and thiamine status. The thiamine concentrations of eggs, muscle (red and white), spleen, kidney (head and trunk), and liver and the transketolase activity of the liver, head kidney, and trunk kidney of fish injected with thiamine dissolved in physiological saline (PST) or physiological saline only (PS) were compared with those of uninjected fish. The injection did not affect the number of fish making the 15-km upstream migration to a collection weir but did affect survival once fish reached the upstream weir, where survival of PST-injected fish was almost twice that of controls. The egg and liver thiamine concentrations in PS fish sampled after their upstream migration were significantly lower than those of uninjected fish collected at the downstream weir, but the white muscle thiamine concentration did not differ between the two groups. At the upper weir, thiamine levels in the liver, spleen, head kidney, and trunk kidney of PS fish were indistinguishable from those of uninjected fish (called "wigglers") suffering from a severe deficiency and exhibiting reduced equilibrium, a stage that precedes total loss of equilibrium and death. For PST fish collected at the upstream weir, total thiamine levels in all tissues were significantly elevated over those of PS fish. Based on the limited number of tissues examined, thiamine status was indicated better by tissue thiamine concentration than by transketolase activity. The adult injection method we used appears to

  9. Ninespine Stickleback Abundance in Lake Michigan Increases After Dreissenid Mussel Invasion

    USGS Publications Warehouse

    Madenjian, Charles P.; Bunnell, David B.; Gorman, Owen T.

    2010-01-01

    Based on data from our annual lakewide bottom trawl survey of Lake Michigan, we determined that density of ninespine sticklebacks Pungitius pungitius increased from an average of 0.234 kg/ha during 1973–1995 to an average of 1.318 kg/ha during 1996–2007. This greater-than-fivefold increase in density coincided with the dreissenid mussel invasion of Lake Michigan. Intervention analysis revealed that ninespine stickleback density in Lake Michigan significantly increased between the two time periods. In contrast, based on data from our annual bottom trawl survey of U.S. waters of Lake Superior, ninespine stickleback density decreased from an average of 0.133 kg/ha during 1978–1999 to an average of only 0.026 kg/ha during 2000–2007. This greater-than-fivefold density decrease, which was found to be significant via intervention analysis, coincided with population recovery for both lean and fat morphotypes of lake trout Salvelinus namaycush in Lake Superior. In contrast to Lake Michigan, dreissenid mussels have not invaded Lake Superior on a lakewide basis. Thus, a comparison of these two lakes indicated that the increase in ninespine stickleback abundance in Lake Michigan was most likely attributable to the dreissenid mussel invasion. In addition, based on our correlation analysis, alewives Alosa pseudoharengus did not have an adverse effect on ninespine stickleback abundance in Lake Michigan. Perhaps the recent increase in biomass of green algae Cladophora spp. associated with the dreissenid mussel invasion improved spawning habitat quality for ninespine sticklebacks and led to their stepwise abundance increase in Lake Michigan beginning in 1996

  10. The effect of temperature and ration size on the growth, body composition, and energy content of juvenile coho salmon

    USGS Publications Warehouse

    Edsall, Thomas A.; Frank, Anthony M.; Rottiers, Donald V.; Adams, Jean V.

    1999-01-01

    Juvenile (postsmolt) coho salmon (Oncorhynchus kitsuch) were held in fresh water in the laboratory at 5, 10, 15, and 18A?C for 8 weeks and fed freshly thawed, juvenile alewives (Alosa pseudoharengus) at rates equal to 1 and 2 % of their wet body weight/day, and also at the ad libitum or unrestricted ration rate. Most rapid growth in weight (1.2% wet body weight/day) occurred among fish fed the ad libitum ration at 15A?C; growth was most rapid at about 10A?C for fish fed the 2% ration (0.7%/day), and the 1% ration (0.1%/day). Gross conversion efficiency was highest at 10A?C for all three ration levels. Gross body constituents and energy content of the test fish changed with temperature and ration during the study. Growth rate was positively related to lipid, energy content, and ration; lipid and energy content were positively related to water temperature; lipid, energy content, growth rate, ration, and water temperature were negatively related to water content; and protein was not related to any of the test variables. At the end of the study, water (68.7 to 76.4%) and lipid (3.5 to 10.4%) content were more variable than ash (1.8 to 3.1%), carbohydrate (0.1 to 1.9%), and protein (16.9 to 19.4%) content. Energy content of the fish increased with ration and was highest for each ration level at 15A?C.

  11. Can diet-dependent factors help explain fish-to-fish variation in thiamine-dependent early mortality syndrome?

    USGS Publications Warehouse

    Brown, S.B.; Arts, M.T.; Brown, L.R.; Brown, M.; Moore, K.; Villella, M.; Fitzsimons, J.D.; Honeyfield, D.C.; Tillitt, D.E.; Zajicek, J.L.; Wolgamood, M.; Hnath, J.G.

    2005-01-01

    To provide insight into the reasons why offspring of certain salmonine females exhibit early mortality syndrome (EMS) in the Great Lakes whereas others do not, we measured the egg concentrations of potential biochemical markers (stable isotopes of nitrogen and carbon, fatty acid signatures, and lipid-soluble carotenoids and vitamins) that are indicative of differing food web and trophic structure. To corroborate the presence of EMS, we also measured the egg content of thiamine vitamers. For all the stocks of coho salmon Oncorhynchus kisutch and Chinook salmon O. tshawytscha we studied, there was a very high correspondence between EMS and low concentrations of unphosphorylated thiamine in unfertilized eggs. For salmonine stocks in the Platte River, Thompson Creek, and the Swan River, Michigan, small but significant shifts occurred in measures of egg carotenoids, retinoids, ??15N depletion, and fatty acid profiles of fish producing normal offspring relative to those exhibiting EMS. Egg thiamine concentrations in Chinook salmon from the Little Manistee River, Michigan, in the low-EMS group were only marginally above the threshold for EMS induction. Along with this small thiamine differential, there was no evidence of differing food web or dietary factors between EMS-positive and normal Chinook salmon from the Little Manistee River. Further investigations are required to determine the potential dietary sources for the observed differences in biochemical markers between EMS-positive and normal fish. These findings are generally consistent with the hypothesis that a more diverse forage base may help to limit overall dietary content of species that contain thiaminase, such as alewives Alosa pseudoharengus, and may lead to improved embryonic survival for feral salmonids. ?? Copyright by the American Fisheries Society 2005.

  12. ESTIMATION OF SURPLUS BIOMASS OF CLUPEIDS IN SMITH MOUNTAIN LAKE, VIRGINIA

    EPA Science Inventory

    Mean annual estimates of surplus biomass of alewife Alosa pseudoharengus and gizzard shad Dorosoma cepedianum in Smith Mountain Lake, Virginia, were calculated using data on the biomass, growth, and mortality of each clupeid species. Surplus biomass, defined as production over a...

  13. Large-scale changes in bloater growth and condition in Lake Huron

    USGS Publications Warehouse

    Prichard, Carson G.; Roseman, Edward F.; Keeler, Kevin M.; O'Brien, Timothy P.; Riley, Stephen C.

    2016-01-01

    Native Bloaters Coregonus hoyi have exhibited multiple strong year-classes since 2005 and now are the most abundant benthopelagic offshore prey fish in Lake Huron, following the crash of nonnative AlewivesAlosa pseudoharengus and substantial declines in nonnative Rainbow Smelt Osmerus mordax. Despite recent recoveries in Bloater abundance, marketable-size (>229 mm) Bloaters remain scarce. We used annual survey data to assess temporal and spatial dynamics of Bloater body condition and lengths at age in the main basin of Lake Huron from 1973 to 2014. Basinwide lengths at age were modeled by cohort for the 1973–2003 year-classes using a von Bertalanffy growth model with time-varying Brody growth coefficient (k) and asymptotic length () parameters. Median Bloater weights at selected lengths were estimated to assess changes in condition by modeling weight–length relations with an allometric growth model that allowed growth parameters to vary spatially and temporally. Estimated Bloater lengths at age declined 14–24% among ages 4–8 for all year-classes between 1973 and 2004. Estimates of  declined from a peak of 394 mm (1973 year-class) to a minimum of 238 mm (1998 year-class). Observed mean lengths at age in 2014 were at all-time lows, suggesting that year-classes comprising the current Bloater population would have to follow growth trajectories unlike those characterizing the 1973–2003 year-classes to attain marketable size. Furthermore, estimated weights of 250-mm Bloaters (i.e., a large, commercially valuable size-class) declined 17% among all regions from 1976 to 2007. Decreases in body condition of large Bloaters are associated with lower lipid content and may be linked to marked declines in abundance of the amphipodsDiporeia spp. in Lake Huron. We hypothesize that since at least 1976, large Bloaters have become more negatively buoyant and may have incurred an increasingly greater metabolic cost performing diel vertical migrations to prey upon the opossum

  14. Fish community dynamics in northeastern Lake Ontario with emphasis on the growth and reproductive success of yellow perch (Perca flavescens) and white perch (Morone americana), 1978 to1997

    USGS Publications Warehouse

    O'Gorman, Robert; Burnett, John A.D.

    2001-01-01

    Fishes were assessed in Guffin, Chaumount, and Black River bays in northeastern Lake Ontario with a 7.9-m (headrope) bottom trawl during late September and early October, 1978 to 1997. Fish density declined in the early 1990s with sharp declines in abundance of spottail shiner (Notropis hudsonius), trout-perch (Percopsis omiscomaycus), and johnny darter (Etheostoma nigrum) occurring in 1993 to 1995. Rising numbers of piscivores, walleye (Stizostedion vitreum) and double-crested cormorant (Phalacrocorax auritus), increased predation pressure, presumably acting in concert with oligotrophication to lower fish density, particularly after 1991 when large numbers of adult alewife (Alosa pseudoharengus) no longer migrated to the northeast basin in spring. Annual mortality of yellow perch (Perca flavescens) from age 2 to 5 rose from 33% in 1980–83 to 65% in 1992–95 and was positively related to piscivore numbers (P = 0.01, r = 0.96, n = 5). Annual mortality of yellow perch from age 0 to 2 also peaked in 1992–95. Abundance of yellow perch YOY in fall varied 40 fold and was not related to water warming in spring (P = 0.45, r = −0.19, n = 18) but was negatively related to the abundance of adult alewives in spring (P = 0.04, r = −0.49, n = 18). Although yellow perch produced moderate to strong year classes each year during 1991–95, stock size failed to increase because of rapidly accelerating mortality. Fully 85% of the variation in mean length of yellow perch YOY was explained by a multiple regression model which included YOY abundance, mean total phosphorus, and cumulative degree days > 13.5°C (P < 0.01, n = 15). Abundance of white perch (Morone americana) YOY varied nearly 200 fold and was not related to water warming or spring alewife abundance (P > 0.15). Variation in mean length of white perch YOY was related to cumulative degree days > 15°C (P < 0.01, r = 0.69).

  15. A synthesis of ecological and fish-community changes in Lake Ontario, 1970-2000

    USGS Publications Warehouse

    Mills, E.L.; Casselman, J.M.; Dermott, R.; Fitzsimons, J.D.; Gal, G.; Holeck, K. T.; Hoyle, J.A.; Johannsson, O.E.; Lantry, B.F.; Makarewicz, J.C.; Millard, E.S.; Munawar, I.F.; Munawar, M.; O'Gorman, R.; Owens, R.W.; Rudstam, L. G.; Schaner, T.; Stewart, T.J.

    2005-01-01

    We assessed stressors associated with ecological and fishcommunity changes in Lake Ontario since 1970, when the first symposium on Salmonid Communities in Oligotrophic Lakes (SCOL I) was held (J. Fish. Res. Board Can. 29: 613-616). Phosphorus controls implemented in the early 1970s were undeniably successful; lower food-web studies showed declines in algal abundance and epilimnetic zooplankton production and a shift in pelagic primary productivity toward smaller organisms. Stressors on the fish community prior to 1970 such as exploitation, sea lamprey (Petromyzon marinus) predation, and effects of nuisance populations of alewife (Alosa pseudoharengus) were largely ameliorated by the 1990s. The alewife became a pivotal species supporting a multi-million-dollar salmonid sport fishery, but alewife-induced thiamine deficiency continued to hamper restoration and sustainability of native lake trout (Salvelinus namaycush). Expanding salmonine populations dependent on alewife raised concerns about predator demand and prey supply, leading to reductions in salmonine stocking in the early 1990s. Relaxation of the predation impact by alewives and their shift to deeper water allowed recovery of native fishes such as threespine stickleback (Gasterosteus aculeatus) and emerald shiner (Notropis atherinoides). The return of the Lake Ontario ecosystem to historical conditions has been impeded by unplanned introductions. Establishment of Dreissena spp. led to increased water clarity and increased vectoring of lower trophic-level production to benthic habitats and contributed to the collapse of Diporeia spp. populations, behavioral modifications of key fish species, and the decline of native lake whitefish (Coregonus clupeaformis). Despite reduced productivity, exotic-species introductions, and changes in the fish community, offshore Mysis relicta populations remained relatively stable. The effects of climate and climate change on the population abundance and dynamics of Lake Ontario

  16. Mitigation of Shore Damage Attributed to the Federal Navigation Structures at Ludington Harbor, Michigan.

    DTIC Science & Technology

    1975-12-01

    Point, Quebec (International Great Lakes Datum, 1955). Lakes Michigan and Huron , connected by the deep and broad straits of Mackinac, act as one...the confluence of Lake Michigan and Lake Huron . This zone is classified as a northern -56- Vie d)OUw i t r ViwLooking North froma Point Located about...White sucker C Ccztos tom-us catostonmus Longnose sucker C Alosa pseudoharengus Alewife C Core gonus artedii Lake herring TE Coregc’nus reighardi

  17. Environmental Baseline Studies of St. Marys River Near Neebish Island, Michigan, Prior to Proposed Extension of Navigation Season, 1981. Great Lakes- St. Lawrence Seaway, Navigation Season Extension Program

    DTIC Science & Technology

    1983-06-01

    to Lake Huron at Detour, Michigan (Figure 1). From its headwaters to Lake Huron the St. Marys River descends approximately 6.7 m (22’). Most of this...conditions at both the Middle Neebish Channel and at a proposed dredge spoil disposal site in Lake Huron . Extensive background data on physical/chemical...Alosa pseudoharengus Alewife Salmonidae Salmons, trouts, whitefishes Coregonus artedii Cisco Coregonus clupeaformis Lake whitefish Osmeridae Smelts

  18. Ascent, dominance, and decline of the alewife in the Great Lakes: Food web interactions and management strategies

    USGS Publications Warehouse

    O'Gorman, Robert; Stewart, Thomas J.; Taylor, William W.; Ferreri, C. Paola

    1999-01-01

    This article chronicles the ascent, dominance, and decline of the alewife (Alosa pseudoharengus) in the Great Lakes and tracks the gradual accumulation of knowledge on the fish's effect on the aquatic community. Changes in management strategies for alewife are followed, and the current management dilemma is framed in light of the alewife's effect on inidigenous fishes and the changing biota and trophic status of the Great Lakes.

  19. Volume 89, Issue4 (September 2004)Articles in the Current Issue:Original PaperSpatial Analysis of Twaite Shad, Alosa fallax (Lacepède, 1803), in the Southern North Sea: Application of Non-Linear Geostatistics as a Tool to Search for Special Areas of Conservation

    NASA Astrophysics Data System (ADS)

    Stelzenmüller, Vanessa; Maynou, Francesc; Ehrich, Siegfried; Zauke, Gerd-Peter

    2004-09-01

    This study aims to evaluate the suitability of non-linear geostatistics and indicator kriging (IK) as a tool in environmental impact assessment and nature conservation, in particular to search for potential Special Areas of Conservation (SAC) for the endangered fish species twaite shad, Alosa fallax (Lacepède, 1803) within the German Exclusive Economical Zone (EEZ) of the North Sea. To analyse the spatial distribution of this fish species, data on standardised biomass index (catch per unit effort, c.p.u.e., kg × 30 min-1) from 1996 to 2001 were used, regarding the third and fourth quarters of each year, respectively. Thereby we assume that the spatial distribution can be described as a time-invariant process. This assumption is supported by information on annual sampling effort, allocation of hauls and spatial distribution of the positive catches. All indicator variograms obtained for different c.p.u.e. cut-off values displayed distinct spatial structures, clearly indicating that the indicator variables were spatially autocorrelated. Gaussian models were fitted by least-squares methods and were evaluated with a goodness-of-fit statistic. Subsequently, IK was employed to estimate the probability of exceeding the c.p.u.e. cut-off values for the twaite shad in the investigation area. These were highest in the Weser- and Elbe-estuary, probably because of migrations of twaite shad to and from estuaries at the time of investigation due to spawning, while within the German EEZ of the North Sea no such areas with increased probabilities could be discerned. Thus, although available data did not allow to identify and implement any SAC in the German EEZ, the methods employed here can be regarded as a promising management tool in biological conservation issues. (

  20. Swimming performance of upstream migrant fishes in open-channel flow: A new approach to predicting passage through velocity barriers

    USGS Publications Warehouse

    Haro, A.; Castro-Santos, T.; Noreika, J.; Odeh, M.

    2004-01-01

    The ability to traverse barriers of high-velocity flow limits the distributions of many diadromous and other migratory fish species, yet very few data exist that quantify this ability. We provide a detailed analysis of sprint swimming ability of six migratory fish species (American shad (Alosa sapidissima), alewife (Alosa pseudoharengus), blueback herring (Alosa aestivalis), striped bass (Morone saxatilis), walleye (Stizostedion vitreum), and white sucker (Catostomus commersoni)) against controlled water velocities of 1.5-4.5 m??s-1 in a large, open-channel flume. Performance was strictly voluntary: no coercive incentives were used to motivate fish to sprint. We used these data to generate models of maximum distance traversed, taking into account effects of flow velocity, body length, and temperature. Although the maximum distance traversed decreased with increasing velocity, the magnitude of this effect varied among species. Other covariate effects were likewise variable, with divergent effects of temperature and nonuniform length effects. These effects do not account for all of the variability in performance, however, and behavioral traits may account for observed interspecific differences. We propose the models be used to develop criteria for fish passage structures, culverts, and breached dams.

  1. Role of origin and release location in pre-spawning distribution and movements of anadromous alewife

    USGS Publications Warehouse

    Frank, Holly J.; Mather, M. E.; Smith, Joseph M.; Muth, Robert M.; Finn, John T.

    2011-01-01

    Capturing adult anadromous fish that are ready to spawn from a self sustaining population and transferring them into a depleted system is a common fisheries enhancement tool. The behaviour of these transplanted fish, however, has not been fully evaluated. The movements of stocked and native anadromous alewife, Alosa pseudoharengus (Wilson), were monitored in the Ipswich River, Massachusetts, USA, to provide a scientific basis for this management tool. Radiotelemetry was used to examine the effect of origin (native or stocked) and release location (upstream or downstream) on distribution and movement during the spawning migration. Native fish remained in the river longer than stocked fish regardless of release location. Release location and origin influenced where fish spent time and how they moved. The spatial mosaic of available habitats and the entire trajectory of freshwater movements should be considered to restore effectively spawners that traverse tens of kilometres within coastal rivers.

  2. Update COSEWIC status report on the shortjaw cisco, Coregonus zenithicus, in Canada

    USGS Publications Warehouse

    Todd, Thomas N.

    2003-01-01

    Extirpated in most of the Great Lakes, the shortjaw cisco, Coregonus zenithicus, is currently found in Lakes Superior and Nipigon in addition to at least 22 Canadian lakes. The species exhibits morphological and genetic variability throughout its range and may consist of more than one distinct taxon. However, a common morph is widely distributed from the Great Lakes to the Northwest Territories, consistent with a hypothesis of preglacial origin for the species. Shortjaw ciscoes have declined because of excessive exploitation by food fisheries, habitat degradation, and predation and competition with introduced and exotic species such as alewife, Alosa pseudoharengus, and rainbow smelt, Osmerus mordax. The status of the species in most Canadian lakes is unknown, but continuing declines in those lakes that have been monitored suggest that the shortjaw cisco should be considered as threatened throughout its range.

  3. Status of river herring stocks in large rivers

    USGS Publications Warehouse

    Schmidt, R.E.; Jessop, B.M.; Hightower, J.E.

    2003-01-01

    We examined long-term data sets from large rivers in the northern, central, and southern parts of the ranges of anadromous river herring (alewife Alosa pseudoharengus and blueback herring A. aestivalis) to assess the current status of these species and for evidence of fishery-induced effects on their demographic characteristics. Both species show signs of overexploitation in all rivers examined, such as reductions in mean age, decreases in percentage of returning spawners, and decreases in abundance. These two species should be managed separately since exploitation within a given river is often biased toward one or the other and there are enough differences in their biology so that a single management option will affect them differently. These species are not distinguished in commercial catches, which hinders understanding of their exploitation. ?? 2003 by the American Fisheries Society.

  4. Combining genetic and demographic information to prioritize conservation efforts for anadromous alewife and blueback herring

    PubMed Central

    Palkovacs, Eric P; Hasselman, Daniel J; Argo, Emily E; Gephard, Stephen R; Limburg, Karin E; Post, David M; Schultz, Thomas F; Willis, Theodore V

    2014-01-01

    A major challenge in conservation biology is the need to broadly prioritize conservation efforts when demographic data are limited. One method to address this challenge is to use population genetic data to define groups of populations linked by migration and then use demographic information from monitored populations to draw inferences about the status of unmonitored populations within those groups. We applied this method to anadromous alewife (Alosa pseudoharengus) and blueback herring (Alosa aestivalis), species for which long-term demographic data are limited. Recent decades have seen dramatic declines in these species, which are an important ecological component of coastal ecosystems and once represented an important fishery resource. Results show that most populations comprise genetically distinguishable units, which are nested geographically within genetically distinct clusters or stocks. We identified three distinct stocks in alewife and four stocks in blueback herring. Analysis of available time series data for spawning adult abundance and body size indicate declines across the US ranges of both species, with the most severe declines having occurred for populations belonging to the Southern New England and the Mid-Atlantic Stocks. While all alewife and blueback herring populations deserve conservation attention, those belonging to these genetic stocks warrant the highest conservation prioritization. PMID:24567743

  5. Permanent genetic resources added to Molecular Ecology Resources Database 1 August 2011-30 September 2011.

    PubMed

    A'Hara, S W; Amouroux, P; Argo, Emily E; Avand-Faghih, A; Barat, Ashoktaru; Barbieri, Luiz; Bert, Theresa M; Blatrix, R; Blin, Aurélie; Bouktila, D; Broome, A; Burban, C; Capdevielle-Dulac, C; Casse, N; Chandra, Suresh; Cho, Kyung Jin; Cottrell, J E; Crawford, Charles R; Davis, Michelle C; Delatte, H; Desneux, Nicolas; Djieto-Lordon, C; Dubois, M P; El-Mergawy, R A A M; Gallardo-Escárate, C; Garcia, M; Gardiner, Mary M; Guillemaud, Thomas; Haye, P A; Hellemans, B; Hinrichsen, P; Jeon, Ji Hyun; Kerdelhué, C; Kharrat, I; Kim, Ki Hwan; Kim, Yong Yul; Kwan, Ye-Seul; Labbe, Ellen M; LaHood, Eric; Lee, Kyung Mi; Lee, Wan-Ok; Lee, Yat-Hung; Legoff, Isabelle; Li, H; Lin, Chung-Ping; Liu, S S; Liu, Y G; Long, D; Maes, G E; Magnoux, E; Mahanta, Prabin Chandra; Makni, H; Makni, M; Malausa, Thibaut; Matura, Rakesh; McKey, D; McMillen-Jackson, Anne L; Méndez, M A; Mezghani-Khemakhem, M; Michel, Andy P; Paul, Moran; Muriel-Cunha, Janice; Nibouche, S; Normand, F; Palkovacs, Eric P; Pande, Veena; Parmentier, K; Peccoud, J; Piatscheck, F; Puchulutegui, Cecilia; Ramos, R; Ravest, G; Richner, Heinz; Robbens, J; Rochat, D; Rousselet, J; Saladin, Verena; Sauve, M; Schlei, Ora; Schultz, Thomas F; Scobie, A R; Segovia, N I; Seyoum, Seifu; Silvain, J-F; Tabone, Elisabeth; Van Houdt, J K J; Vandamme, S G; Volckaert, F A M; Wenburg, John; Willis, Theodore V; Won, Yong-Jin; Ye, N H; Zhang, W; Zhang, Y X

    2012-01-01

    This article documents the addition of 299 microsatellite marker loci and nine pairs of single-nucleotide polymorphism (SNP) EPIC primers to the Molecular Ecology Resources (MER) Database. Loci were developed for the following species: Alosa pseudoharengus, Alosa aestivalis, Aphis spiraecola, Argopecten purpuratus, Coreoleuciscus splendidus, Garra gotyla, Hippodamia convergens, Linnaea borealis, Menippe mercenaria, Menippe adina, Parus major, Pinus densiflora, Portunus trituberculatus, Procontarinia mangiferae, Rhynchophorus ferrugineus, Schizothorax richardsonii, Scophthalmus rhombus, Tetraponera aethiops, Thaumetopoea pityocampa, Tuta absoluta and Ugni molinae. These loci were cross-tested on the following species: Barilius bendelisis, Chiromantes haematocheir, Eriocheir sinensis, Eucalyptus camaldulensis, Eucalyptus cladocalix, Eucalyptus globulus, Garra litaninsis vishwanath, Garra para lissorhynchus, Guindilla trinervis, Hemigrapsus sanguineus, Luma chequen. Guayaba, Myrceugenia colchagüensis, Myrceugenia correifolia, Myrceugenia exsucca, Parasesarma plicatum, Parus major, Portunus pelagicus, Psidium guayaba, Schizothorax richardsonii, Scophthalmus maximus, Tetraponera latifrons, Thaumetopoea bonjeani, Thaumetopoea ispartensis, Thaumetopoea libanotica, Thaumetopoea pinivora, Thaumetopoea pityocampa ena clade, Thaumetopoea solitaria, Thaumetopoea wilkinsoni and Tor putitora. This article also documents the addition of nine EPIC primer pairs for Euphaea decorata, Euphaea formosa, Euphaea ornata and Euphaea yayeyamana.

  6. Migratory Patterns of American Shad (Alosa Sapidissima) Revealed by Natural Geochemical Tags in Otoliths

    DTIC Science & Technology

    2007-02-01

    geographic indicators of natal origins of monarch butterflies in eastern North America. Oecologia 120: 397-404. Hoff, G.R., & Fuiman, L.A. 1995... butterflies (Chamberlain et al. 1997; Hobson et al. 1999; Rubenstein et al. 2002). Such remarkable movements are not restricted to terrestrial... butterflies have been successfully studied using natural gradients in hydrogen, carbon, and nitrogen isotope ratios that are recorded in feather and wing

  7. Ultrastructural study of the spermatozoon of Pronoprymna ventricosa (Digenea, Baccigerinae), parasite of the twaite shad Alosa fallax Lacepede (Pisces, Teleostei).

    PubMed

    Quilichini, Yann; Foata, Josephine; Marchand, Bernard

    2007-09-01

    In this paper, we describe the ultrastructural organisation of the spermatozoon of a Digenea Baccigerinae Pronoprymna ventricosa. This spermatozoon possesses the elements found in the others digeneans: two axonemes with 9 + "1" pattern, a mitochondrion, a nucleus, cortical microtubules and external ornamentations. However, this spermatozoon presents two particularities. The first is the presence of a single field of cortical microtubules disposed in the ventral side (mitochondrion side) of the spermatozoon. In the other digeneans, two fields of cortical microtubules are observed between the two axonemes. The second is the presence of external ornamentations not associated with cortical microtubules. These two points have, to our knowledge, never been described in another digenean. Moreover, a separation in two groups of the digenean spermatozoa is proposed in relation to the localisation of the external ornamentations. We propose to distinguish a first group exhibiting these elements in the proximal part of the spermatozoon and a second one with external ornamentations in a second part of the gamete.

  8. Genetic diversity and differentiation in a wide ranging anadromous fish, American shad (Alosa sapidissima), is correlated with latitude.

    PubMed

    Hasselman, Daniel J; Ricard, Daniel; Bentzen, Paul

    2013-03-01

    Studies that span entire species ranges can provide insight into the relative roles of historical contingency and contemporary factors that influence population structure and can reveal patterns of genetic variation that might otherwise go undetected. American shad is a wide ranging anadromous clupeid fish that exhibits variation in demographic histories and reproductive strategies (both semelparity and iteroparity) and provides a unique perspective on the evolutionary processes that govern the genetic architecture of anadromous fishes. Using 13 microsatellite loci, we examined the magnitude and spatial distribution of genetic variation among 33 populations across the species' range to (i) determine whether signals of historical demography persist among contemporary populations and (ii) assess the effect of different reproductive strategies on population structure. Patterns of genetic diversity and differentiation among populations varied widely and reflect the differential influences of historical demography, microevolutionary processes and anthropogenic factors across the species' range. Sequential reductions of diversity with latitude among formerly glaciated rivers are consistent with stepwise postglacial colonization and successive population founder events. Weak differentiation among U.S. iteroparous populations may be a consequence of human-mediated gene flow, while weak differentiation among semelparous populations probably reflects natural gene flow. Evidence for an effect of reproductive strategy on population structure suggests an important role for environmental variation and suggests that the factors that are responsible for shaping American shad life history patterns may also influence population genetic structure.

  9. Angler-caught piscivore diets reflect fish community changes in Lake Huron

    USGS Publications Warehouse

    Roseman, Edward F.; Schaeffer, Jeff; Bright, Ethan; Fielder, David G.

    2014-01-01

    Examination of angler-caught piscivore stomachs revealed that Lake Trout Salvelinus namaycush, Chinook Salmon Oncorhynchus tshawytscha, and Walleyes Sander vitreus altered theirdiets in response to unprecedented declines in Lake Huron's main-basin prey fish community.Diets varied by predator species, season, and location but were nearly always dominated numerically by some combination of Alewife Alosa pseudoharengus, Rainbow Smelt Osmerus mordax, Emerald Shiner Notropis atherinoides, Round Goby Neogobius melanostomus, or terrestrial insects. Rainbow Trout Oncorhynchus mykiss (steelhead), Coho Salmon Oncorhynchus kisutch, and Atlantic Salmon Salmo salar had varied diets that reflected higher contributions of insects. Compared with an earlier (1983–1986) examination of angler-caught predator fishes from Lake Huron, the contemporary results showed an increase in consumption of nontraditional prey (including conspecifics), use of smaller prey, and an increase in insects in the diet, suggesting that piscivores were faced with chronic prey limitation during this study. The management of all piscivores in Lake Huron will likely require consideration of the pervasive effects of changes in food webs, especially if prey fish remain at low levels.

  10. The contribution of cold winter temperatures to the 2003 alewife population collapse in Lake Huron

    USGS Publications Warehouse

    Dunlop, Erin; Riley, Stephen C.

    2013-01-01

    The Lake Huron ecosystem has recently undergone dramatic changes. As part of those changes, the once highly abundant non-native alewife Alosa pseudoharengus population crashed in 2003 and has yet to recover. The purpose of this study was to evaluate whether temperature played a role in the population crash, because historically alewife have been subject to die-off events in response to cold temperatures in other lakes. Long-term climate data (1973–2009) showed that the winter of 2002–2003 exhibited the largest drop in degree days relative to the previous year, had the most extensive average March ice coverage, and was among the coldest years on record. However, since 2003, winter temperatures have not been overly cold, and air temperature has shown an increasing trend. Also, the relationship between temperature and alewife abundance between 1975 and 2006 was non-significant. Therefore, although we found evidence that cold winter temperatures contributed to the abrupt decline of alewife in 2003, they could not explain why the population failed to recover as it had after previous cold winters. Historically, Chinook salmon abundance contributed to long-term trends in alewife abundance, however, we found predation by Chinook to play a lesser role on the 2003 alewife collapse. In the absence of direct estimates of food availability, analyses of alewife length data suggest that a declining prey base altered the ecosystem conditions for alewife, possibly contributing to their collapse and lack of recovery.

  11. Use of fish-otolith-length regressions to infer size of double-crested cormorant prey fish from recovered otoliths in Lake Ontario

    USGS Publications Warehouse

    Ross, Robert M.; Johnson, James H.; Adams, Connie M.

    2005-01-01

    To provide a method for estimating fish size from fish otoliths for forensic applications or other predictive uses, morphometric measurements were obtained from three centrarchid fishes (pumpkinseed [Lepomis gibbosus], rock bass [Ambloplites rupestris], and smallmouth bass [Micropterus dolomieu]), two percids (yellow perch [Perca flavescens] and walleye [Stizostedion vitreum]), and one clupeid (alewife [Alosa pseudoharengus]) from the eastern basin of Lake Ontario. These species are the principal or economically important prey of Double-crested Cormorants (Phalacrocorax auritus), whose diet can be determined from regurgitated digestive pellets containing fish otoliths. A fuller understanding of the ecosystem roles of cormorants requires estimation of prey-fish size, obtainable from regressions of otolith length on fish length. Up to 100 fish of each species were collected from eastern Lake Ontario and measured for total length and otolith length. Least-squares regressions of otolith length on fish length were calculated for all species, covering life-stage ranges of immature fish to large adults near maximum known size. The regressions with 95% confidence intervals may be applicable outside the Lake Ontario ecosystem if used with caution.

  12. Species interactions of the alewife in the Great Lakes

    USGS Publications Warehouse

    Smith, Stanford H.

    1970-01-01

    The alewife (Alosa pseudoharengus) has caused serious problems in the Great Lakes for almost 100 years. It entered Lake Ontario in abundance via the Erie Canal during the 1860's when major piscivores were declining, and became the dominant species in the lake during the 1870's. The alewife subsequently spread throughout the Great Lakes and became the dominant species in Lakes Huron and Michigan as major piscivores declined. In lakes where it became extremely abundant, the shallow-water planktivores declined in the first decade after alewife establishment, the minor piscivores increased then declined in the second decade, and the deep-water planktivores declined in the third decade. The consequence has been a general reduction in fishery productivity. Rehabilitation will require extreme reduction of the alewife, and restoration of an interacting complex of deep- and shallow-water forage species, and minor and major piscivores, either by reestablishing species affected by the alewife, or by the introduction of new species that can thrive under the new ecological conditions of the lakes.

  13. Reappearance of deepwater sculpin in Lake Ontario: Resurgence or last gasp of a doomed population?

    USGS Publications Warehouse

    Lantry, B.F.; O'Gorman, R.; Walsh, M.G.; Casselman, J.M.; Hoyle, J.A.; Keir, M.J.; Lantry, J.R.

    2007-01-01

    Deepwater sculpin (Myoxocephalus thompsonii) were abundant in Lake Ontario in the 1920s and at least common into the 1940s. By the 1960s they were rare and, thereafter, some considered the population extirpated even though a synoptic survey of the lake in 1972 produced three, relatively large (148–165 mm total length, TL), and presumably old, specimens from the northern half of the lake. Deepwater sculpin were absent from annual survey catches in the 1980s and did not reappear until 1996, when three were caught in northern Lake Ontario. Isolated collections of deepwater sculpin continued during 1998–2004. Catches during 1996–2004 included five smaller individuals, 89–118 mm TL. In 2005, catches increased sharply, with 18 deepwater sculpin collected from southern waters and one from northern waters. Moreover, young, small sculpin were dominant in 2005—16 of the 19 sculpins averaged 68 ± 12 mm total length (± 1 s.d.). The young fish observed since 1996 could have originated from reproduction by the small in-lake population, from downstream drift of planktonic larvae from Lake Huron, or both. The presence of juveniles is a clear sign that conditions for survival of young deepwater sculpin are becoming more favorable, perhaps because of reduced abundance of alewife (Alosa pseudoharengus), a pelagic planktivore linked to depression of deepwater sculpin in Lake Michigan, and also low abundances of burbot (Lota lota) and lake trout (Salvelinus namaycush), benthic piscivores.

  14. Mysid and fish zooplanktivory in Lake Ontario: quantification of direct and indirect effects

    USGS Publications Warehouse

    Gal, Gideon; Rudstam, Lars G.; Mills, Edward L.; Lantry, Jana R.; Johannsson, Ora E.; Greene, C.

    2011-01-01

    Mysis relicta and planktivorous fish feed on zooplankton in Lake Ontario and form a trophic triangle that includes intraguild predation by fish on mysids. Thus, fish affect zooplankton both directly and indirectly. To evaluate the importance of alewife (Alosa pseudoharengus), rainbow smelt (Osmerus mordax), and mysids as zooplanktivores in Lake Ontario, we measured abundances and distributions, assessed diets, and computed mysid and fish consumption rates based on bioenergetics models. We further estimated indirect effects by comparing clearance rates given observed and potential mysid distributions. Estimated consumption rates varied widely with season and water depth and ranged between 2.6 x 10-3 and 1.3 gm-2day-1 for mysids and between 1.4 x 10-3 and 0.5 gm-2day-1 for fish, representing a daily removal of zooplankton of up to 10.2%-day-1 and 2.0%-day-1 by mysids and fish, respectively. Mysid planktivory exceeded fish planktivory in May and August, but fish planktivory dominated in October. Estimated mysid planktivory rates were 2- to 90-fold lower than the potential rate if mysids moved to temperatures that maximized their predation rates, suggesting an indirect positive effect of fish on zooplankton.

  15. Diet niches of major forage fish in Lake Michigan

    USGS Publications Warehouse

    Davis, B.M.; Savino, J.F.; Ogilvie, L.M.; ,

    2007-01-01

    A large complex of coregonine species historically dominated the fish community of Lake Michigan. The current species complex is simplified with one remaining coregonine, bloater (Coregonus hoyi), deepwater sculpin (Myoxocephalus thompsoni), slimy sculpin (Cottus cognatus), and two dominant invaders, alewife (Alosa pseudoharengus) and rainbow smelt (Osmerus mordax). To better understand the diet relationships of the major offshore forage fishes now in Lake Michigan, diets of bloater, alewife, rainbow smelt, deepwater sculpin, and slimy sculpin were compared. The three sites, chosen to represent northern, central, and southern components of the lake, were sampled during spring, summer, and fall in 1994, and spring and fall in 1995. Forage fishes had diverse and variable diets, with niches differentiated by prey type or location. Diporeia hoyi, Mysis relicta, and zooplankton were the major diet items. The index of relative importance showed benthic (slimy and deepwater sculpins) and pelagic (alewife, rainbow smelt) feeding strategies with opportunistic bloaters incorporating both feeding strategies. Highest diet overlaps were between species of sculpin, and between large and small bloaters; both groups partitioned food by size. Though competition for food may be minimized by spatial segregation of potential competitors, the forage fish in Lake Michigan apparently partition food resources. Fishery management models incorporating food habits of pelagic forage fish would need to take into account diet variation associated with location and season. ?? 2007 E. Schweizerbart'sche Verlagsbuchhandlung.

  16. Fall diets of alewife, rainbow smelt, and slimy sculpin in the profundal zone of southern Lake Ontario during 1994-2005 with an emphasis on occurrence of Mysis relicta

    USGS Publications Warehouse

    Walsh, M.G.; O'Gorman, R.; Strang, T.; Edwards, W.H.; Rudstam, L. G.

    2008-01-01

    In Lake Ontario, factors including the collapse of the burrowing amphipod, Diporeia spp., changes in the distribution and composition of the prey fish community, and occurrence of exotic cladocerans Bythotrephes longimanus and Cercopagis pengoi have led to changes in predation pressure on the remaining native profundal macroinvertebrate, Mysis relicta. We conducted a diet study on three important prey fishes, alewife (Alosa pseudoharengus), rainbow smelt (Osmerus mordax), and slimy sculpin (Cottus cognatus) in 2002-2005 at depths 75-130 m along the south shore of Lake Ontario to evaluate the current role of Mysis in the diets of these species relative to earlier studies and previously unpublished data from 1994-1995. Mysis have remained an important prey item for alewife, rainbow smelt, and slimy sculpin in the profundal zone of southern Lake Ontario through 2005, indicating that the population has been able to sustain itself following the collapse of Diporeia. Although the occurrence of Diporeia in prey fish diets was minimal in 2003-2005, Bythotrephes longimanus and Cercopagis pengoi played an important role in the diet of alewife and a minor role in the diet of rainbow smelt, and may actually serve to mitigate predation pressure on Mysis, particularly in years when they are very abundant. Conversely, without Diporeia, the benthic slimy sculpin was primarily reliant on Mysis as a prey item and would be most vulnerable to a decline in the Mysis population. Copyright ?? 2008 AEHMS.

  17. Testing for synchrony in recruitment among four Lake Michigan fish species

    USGS Publications Warehouse

    Bunnell, David; Höök, Tomas O.; Troy, Cary D.; Liu, Wentao; Madenjian, Charles P.; Adams, Jean V.

    2017-01-01

    In the Great Lakes region, multiple fish species display intra-specific spatial synchrony in 28 recruitment success, with inter-annual climate variation hypothesized as the most likely driver. 29 In Lake Michigan, we evaluated whether climatic or other physical variables could also induce 30 spatial synchrony across multiple species, including bloater (Coregonus hoyi), rainbow smelt 31 (Osmerus mordax), yellow perch (Perca flavescens), and alewife (Alosa pseudoharengus). The 32 residuals from stock-recruitment relationships revealed yellow perch recruitment to be correlated 33 with recruitment of both rainbow smelt (r = 0.37) and alewife (r = 0.36). Across all four species, 34 higher than expected recruitment occurred in 5 years between 1978 and 1987 and then switched 35 to lower than expected recruitment in 5 years between 1996 and 2004. Generalized additive 36 models revealed warmer spring and summer water temperatures and lower wind speeds 37 corresponded to higher than expected recruitment for the nearshore-spawning species, and 38 overall variance explained ranged from 14% (yellow perch) to 61% (alewife). For all species 39 but rainbow smelt, higher recruitment also occurred in extremely high or low years of the North 40 Atlantic Oscillation index. Future development of indices that describe the physical Great Lakes 41 environment could improve understanding of how climate can synchronize fish populations 42 within and across species.

  18. Prioritizing removal of dams for passage of diadromous fishes on a major river system

    USGS Publications Warehouse

    Kocovsky, P.M.; Ross, R.M.; Dropkin, D.S.

    2009-01-01

    Native diadromous fishes have been extirpated from much of the Susquehanna River system for nearly a century. Recent restoration efforts have focused on removal of dams, but there are hundreds of dams and presently there is no biologically based system to assist in prioritizing their removal. We present a new method that uses existing habitat suitability index models (HSI) for American shad Alosa sapidissima, alewife A. pseudoharengus, blueback herring A. aestivalis, and American eel Anguilla rostrata to prioritize the removal of non-hydropower dams within the Susquehanna River system. We ranked HSI scores for each of the four species, association between a landscape-scale factor and HSIs, length of river opened by removing a dam, and distance from the mouth at Chesapeake Bay for each dam and then calculated a mean rank prioritization for dam removal by averaging the ranks for the seven criteria. This prioritization method is resistant to outliers, is not strongly affected by somewhat arbitrary decisions on metrics included in the analysis, and provides a biologically based prioritization for dam removal that can be easily amended to include other metrics or adapted to other river systems and that complements other social and economic considerations that must be included in decisions to remove dams.

  19. Influence of diet of double-crested cormorants on thiamine, lead, and mineral contents of their eggs

    USGS Publications Warehouse

    Ketola, H. George; Johnson, James H.; Adams, C.M.; Farquhar, J.F.

    2009-01-01

    Throughout much of the Great Lakes basin, reproduction of several fish species is impaired by deficiency of thiamine in their eggs, an effect attributed to consumption of thiaminase-containing forage species, primarily alewife (Alosa pseudoharengus.) Because the double-crested cormorant (Phalacrocorax auritus) nesting on islands in Lake Ontario is known to consume considerable amounts of alewife, we examined cormorant food habits and measured thiamine content in eggs collected in 1999 from six separate nests of cormorants from colonies near Lake Ontario and contrasted them with food habits and eggs of cormorants from Oneida Lake where the alewife is rare. Thiamine concentrations in eggs varied between 4.31 and 11.24 nmoleslg with no significant (P>0.18) difference between mean concentrations for Lake Ontario and Oneida Lake (8.08 vs 8.36 nmoles/g) even though alewife comprised approximately 65 vs 0 % of their diets, respectively. Consumption of other thiaminase-containing species was minor in both lakes. Therefore, consumption of alewife and other thiaminase containing fishes by cormorants on Lake Ontario did not appear to significantly impair the levels of thiamine in their eggs. However, we found that the concentration of thiamine in eggs (T; nmoles/g) was inversely related (P<0.02) to lead (Pb) concentration (μg/g) according to the equation: T = −3.142 Pb + 16.25. This relationship may reflect the known ability of thiamine to chelate lead and increase its excretion.

  20. Influence of diet of double-crested cormorants on thiamine, lead, and mineral contents of their eggs

    USGS Publications Warehouse

    Ketola, H.G.; Johnson, J.H.; Adams, C.M.; Farquhar, J.F.

    2009-01-01

    Throughout much of the Great Lakes basin, reproduction of several fish species is impaired by deficiency of thiamine in their eggs, an effect attributed to consumption of thiaminase-containing forage species, primarily alewife (Alosa pseudoharengus). Because the double-crested cormorant (Phalacrocorax auritus) nesting on islands in Lake Ontario is known to consume considerable amounts of alewife, we examined cormorant food habits and measured thiamine content in eggs collected in 1999 from six separate nests of cormorants from colonies near Lake Ontario and contrasted them with food habits and eggs of cormorants from Oneida Lake where the alewife is rare. Thiamine concentrations in eggs varied between 4.31 and 11.24 nmoles/g with no significant (P>0.18) difference between mean concentrations for Lake Ontario and Oneida Lake (8.08 vs 8.36 nmoles/g) even though alewife comprised approximately 65 vs 0 % of their diets, respectively. Consumption of other thiaminase-containing species was minor in both lakes. Therefore, consumption of alewife and other thiaminase containing fishes by cormorants on Lake Ontario did not appear to significantly impair the levels of thiamine in their eggs. However, we found that the concentration of thiamine in eggs (T; nmoles/g) was inversely related (P<0.02) to lead (Pb) concentration (µg/g) according to the equation: T = -3.142 Pb + 16.25. This relationship may reflect the known ability of thiamine to chelate lead and increase its excretion.

  1. Landscape scale measures of steelhead (Oncorhynchus mykiss) bioenergetic growth rate potential in Lake Michigan and comparison with angler catch rates

    USGS Publications Warehouse

    Hook, T.O.; Rutherford, E.S.; Brines, Shannon J.; Geddes, C.A.; Mason, D.M.; Schwab, D.J.; Fleischer, G.W.

    2004-01-01

    The relative quality of a habitat can influence fish consumption, growth, mortality, and production. In order to quantify habitat quality, several authors have combined bioenergetic and foraging models to generate spatially explicit estimates of fish growth rate potential (GRP). However, the capacity of GRP to reflect the spatial distributions of fishes over large areas has not been fully evaluated. We generated landscape scale estimates of steelhead (Oncorhynchus mykiss) GRP throughout Lake Michigan for 1994-1996, and used these estimates to test the hypotheses that GRP is a good predictor of spatial patterns of steelhead catch rates. We used surface temperatures (measured with AVHRR satellite imagery) and acoustically measured steelhead prey densities (alewife, Alosa pseudoharengus) as inputs for the GRP model. Our analyses demonstrate that potential steelhead growth rates in Lake Michigan are highly variable in both space and time. Steelhead GRP tended to increase with latitude, and mean GRP was much higher during September 1995, compared to 1994 and 1996. In addition, our study suggests that landscape scale measures of GRP are not good predictors of steelhead catch rates throughout Lake Michigan, but may provide an index of interannual variation in system-wide habitat quality.

  2. Seasonal consumption of Hemimysis anomala by fish in southeastern Lake Ontario, 2009-2010

    USGS Publications Warehouse

    Lantry, B.F.; Gumtow, C.F.; Walsh, M.G.; Weidel, B.C.; Boscarino, B.T.; Rudstam, L. G.

    2012-01-01

    We investigated the seasonal occurrence of Hemimysis anomala in the diets of fish that prey on macroinvertebrates at two sites with established Hemimysis populations east of Oswego, NY, during 2009-2010. In 2009, we examined 320 stomachs from 10 species and found Hemimysis only in alewife (Alosa pseudoharengus), rockbass (Ambloplites rupestris), and yellow perch (Perca flavescens). Of those species, alewife consumed Hemimysis most frequently and it represented a greater proportion of their diets. During 2009, the dry weight composition of Hemimysis in alewife diets varied seasonally between <1% in June, 5% in July, 98.5% in August, and 18.8% in September. In contrast, we examined 667 stomachs from 15 species in 2010 and observed Hemimysis in only one alewife and two rockbass stomachs. For alewife from September 2009, we found no relationship between predator size and the number of Hemimysis consumed, or between the presence of Hemimysis in fish diets and the presence of other diet taxa or diet diversity. Fish diets collected as bycatch from other assessments revealed large numbers of Hemimysis in fishes that had not previously been observed consuming Hemimysis in Lake Ontario, including cisco (Coregonus artedi) and white perch (Morone americana). Our results indicate Hemimysis consumption by nearshore fish can be high, but that it is variable across seasons and years, and may be most prevalent in fish that feed up in the water column, at or near dark, and have the ability to consume swift moving prey like Mysis diluviana or small fish.

  3. Evidence that PCBs are approaching stable concentrations in Lake Michigan fishes

    USGS Publications Warehouse

    Stow, Craig A.; Carpenter, Stephen R.; Eby, Lisa A.; Amrhein, James F.; Hesselberg, Robert J.

    1995-01-01

    We examined PCB concentration data for seven species of Lake Michigan fishes to determine what trends were apparent °20 yr after PCB restrictions became effective. Total PCB concentrations in all seven species, lake trout (Salvelinus namaycush), rainbow trout (Oncorhynchus mykiss), brown trout (Salmo trutta), chinook salmon (Oncorhynchus tshawytscha), coho salmon (Oncorhynchus kisutch), alewife (Alosa pseudoharengus), and bloater chub (Coregonus hoyi) declined and appeared to stabilize in the mid-to-late 1980s. Concentrations in two species, chinook and coho salmon, appear to have increased slightly since the late 1980s. All species are currently well below the high PCB levels that existed when PCB use was curtailed in the 1970s. We believe stabilizing concentrations are the result of large pools of PCBs that are being recycled in the environment. Atmospheric and sediment PCB inputs to the lake probably constitute current PCB sources. Increasing concentrations in chinook and coho salmon are likely the result of changing growth dynamics caused by alterations in the mid-trophic levels of the food web. Median stable PCB concentrations estimated in this analysis are below the current FDA action level of 2 mg/kg, but not appreciably below this threshold. Improvements beyond these levels may result if management practices that maximize fish growth rates are implemented. Detection of future improvements in PCB levels may require samples in the range of 1000-2000 fish because of the high variability in PCB concentrations among individuals.

  4. Changes in the nearshore and offshore zooplankton communities in Lake Ontario: 1981-88

    USGS Publications Warehouse

    Johannsson, Ora E.; Mills, Edward L.; O'Gorman, Robert

    1991-01-01

    We examined trends and factors influencing changes in nearshore and offshore zooplankton abundance and composition in Lake Ontario between 1981 and 1988. In the nearshore (southshore and eastern basin), zooplankton abundance decreased and shifts occurred in the relative abundances of Bosmina longirostris and Daphnia retrocurva (eastern basin) and Daphnia retrocurva and Daphnia galeata mendotae (southshore). These changes could have resulted from increased vertebrate predation or reduced food resources which intensified the effects of predation. In the offshore, the first appearance (FA) of the larger, less common cladoceran species occurred earlier in the season as of 1985. FA was correlated with cumulative epilimnetic temperature (CET) and the catch per unit effort (CPUE) of alewife (Alosa pseudoharengus) a?Y165 mm caught in U.S. waters in the spring. In 1987, when CET was high and CPUE of alewife a?Y165 mm was low, large populations of these cladocerans developed in June and July. Bythotrephes cederstroemi, a recent invader in the Great Lakes, was abundant only in 1987 when the CPUE of alewife was lowest. Changes in zooplankton abundance, development, and composition along the nearshore-offshore gradient reflected effects of temperature, habitat, and planktivory on the community.

  5. Dynamics of the Lake Michigan food web, 1970-2000

    USGS Publications Warehouse

    Madenjian, Charles P.; Fahnenstiel, Gary L.; Johengen, Thomas H.; Nalepa, Thomas F.; Vanderploeg, Henry A.; Fleischer, Guy W.; Schneeberger, Philip J.; Benjamin, Darren M.; Smith, Emily B.; Bence, James R.; Rutherford, Edward S.; Lavis, Dennis S.; Robertson, Dale M.; Jude, David J.; Ebener, Mark P.

    2002-01-01

    Herein, we document changes in the Lake Michigan food web between 1970 and 2000 and identify the factors responsible for these changes. Control of sea lamprey (Petromyzon marinus) and alewife (Alosa pseudoharengus) populations in Lake Michigan, beginning in the 1950s and 1960s, had profound effects on the food web. Recoveries of lake whitefish (Coregonus clupeaformis) and burbot (Lota lota) populations, as well as the buildup of salmonine populations, were attributable, at least in part, to sea lamprey control. Based on our analyses, predation by salmonines was primarily responsible for the reduction in alewife abundance during the 1970s and early 1980s. In turn, the decrease in alewife abundance likely contributed to recoveries of deepwater sculpin (Myoxocephalus thompsoni), yellow perch (Perca flavescens), and burbot populations during the 1970s and 1980s. Decrease in the abundance of all three dominant benthic macroinvertebrate groups, including Diporeia, oligochaetes, and sphaeriids, during the 1980s in nearshore waters (50 m deep) of Lake Michigan, was attributable to a decrease in primary production linked to a decline in phosphorus loadings. Continued decrease in Diporeia abundance during the 1990s was associated with the zebra mussel (Dreissena polymorpha) invasion, but specific mechanisms for zebra mussels affecting Diporeia abundance remain unidentified.

  6. Lake Ontario: Food web dynamics in a changing ecosystem (1970-2000)

    USGS Publications Warehouse

    Mills, E.L.; Casselman, J.M.; Dermott, R.; Fitzsimons, J.D.; Gal, G.; Holeck, K. T.; Hoyle, J.A.; Johannsson, O.E.; Lantry, B.F.; Makarewicz, J.C.; Millard, E.S.; Munawar, I.F.; Munawar, M.; O'Gorman, R.; Owens, R.W.; Rudstam, L. G.; Schaner, T.; Stewart, T.J.

    2003-01-01

    We examined stressors that have led to profound ecological changes in the Lake Ontario ecosystem and its fish community since 1970. The most notable changes have been reductions in phosphorus loading, invasion by Dreissena spp., fisheries management through stocking of exotic salmonids and control of sea lamprey (Petromyzon marinus), and fish harvest by anglers and double-crested cormorants (Phalacrocorax auritus). The response to these stressors has led to (i) declines in both algal photosynthesis and epilimnetic zooplankton production, (ii) decreases in alewife (Alosa pseudoharengus) abundance, (iii) declines in native Diporeia and lake whitefish (Coregonus clupeaformis), (iv) behavioral shifts in alewife spatial distribution benefitting native lake trout (Salvelinus namaycush), threespine stickleback (Gasterosteus aculeatus), and emerald shiner (Notropis atherinoides) populations, (v) dramatic increases in water clarity, (vi) predation impacts by cormorants on select fish species, and (vii) lake trout recruitment bottlenecks associated with alewife-induced thiamine deficiency. We expect stressor responses associated with anthropogenic forces like exotic species invasions and global climate warming to continue to impact the Lake Ontario ecosystem in the future and recommend continuous long-term ecological studies to enhance scientific understanding and management of this important resource.

  7. 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.

  8. Lake Michigan offshore ecosystem structure and food web changes from 1987 to 2008

    USGS Publications Warehouse

    Rogers, Mark W.; Bunnell, David B.; Madenjian, Charles P.; Warner, David M.

    2014-01-01

    Ecosystems undergo dynamic changes owing to species invasions, fisheries management decisions, landscape modifications, and nutrient inputs. At Lake Michigan, new invaders (e.g., dreissenid mussels (Dreissena spp.), spiny water flea (Bythotrephes longimanus), round goby (Neogobius melanostomus)) have proliferated and altered energy transfer pathways, while nutrient concentrations and stocking rates to support fisheries have changed. We developed an ecosystem model to describe food web structure in 1987 and ran simulations through 2008 to evaluate changes in biomass of functional groups, predator consumption, and effects of recently invading species. Keystone functional groups from 1987 were identified as Mysis, burbot (Lota lota), phytoplankton, alewife (Alosa pseudoharengus), nonpredatory cladocerans, and Chinook salmon (Oncorhynchus tshawytscha). Simulations predicted biomass reductions across all trophic levels and predicted biomasses fit observed trends for most functional groups. The effects of invasive species (e.g., dreissenid grazing) increased across simulation years, but were difficult to disentangle from other changes (e.g., declining offshore nutrient concentrations). In total, our model effectively represented recent changes to the Lake Michigan ecosystem and provides an ecosystem-based tool for exploring future resource management scenarios.

  9. Using linear models with correlated errors to analyze changes in abundance of Lake Michigan fishes: 1973-1992

    USGS Publications Warehouse

    Fabrizio, Mary C.; Raz, Jonathan; Bandekar, Ramanath R.

    2000-01-01

    We examined annual changes in relative abundance of Lake Michigan fishes using linear models with correlated errors in space and time. Abundance of bloater (Coregonus hoyi), deepwater sculpin (Myoxocephalus thompsoni), slimy sculpin (Cottus cognatus), alewife (Alosa pseudoharengus), and rainbow smelt (Osmerus mordax) was monitored with bottom trawls at 10 discrete depths (between 18 and 110 m) off eight fixed ports from 1973 to 1992. The model describing abundance included fixed effects of year, port, depth, and interaction terms as well as quadratic and cubic effects of year and depth because changes in abundance were not strictly linear. Observed temporal trends in abundance varied with species and depth. Additionally, trends in alewife and slimy sculpin abundances depended on port. Cubic trends in the abundance of bloater and quadratic trends in deepwater sculpin and rainbow smelt abundances were similar among ports, permitting lakewide inferences for these species. Mean bloater abundance was low throughout the 1970s, increased during the 1980s, and reached high levels by 1990. Mean abundances of deepwater sculpin and rainbow smelt increased from 1973 to the mid-1980s and declined thereafter. The linear model with correlated errors can be readily applied to repeated-measures data from other fixed-station fishery surveys and is appropriate for data exhibiting spatial and temporal autocorrelations.

  10. Interpopulation variation in a fish predator drives evolutionary divergence in prey in lakes.

    PubMed

    Walsh, Matthew R; Post, David M

    2011-09-07

    Ecological factors are known to cause evolutionary diversification. Recent work has shown that evolution in strongly interacting predator species has reciprocal impacts on ecosystems. These divergent impacts of predators may alter the selective landscape and cause the evolution of prey. Yet, this link between intraspecific variation and evolution is unexplored. We compared the life history of a species of zooplankton (Daphnia ambigua) from lakes in New England in which the dominant planktivorous predator, the alewife (Alosa pseudoharengus), differs in feeding traits and migratory behaviour. Anadromous alewife (seasonal migrants) exhibit larger gapes, gill-raker spacing and target larger prey than landlocked alewife (year-round freshwater resident). In 'anadromous' lakes, Daphnia are abundant in the spring but extirpated by alewife predation in summer. Daphnia are rare year-round in 'landlocked' lakes. We show that Daphnia from lakes with anadromous alewife grew faster, matured earlier but at the same size and produced more offspring than Daphnia from lakes with landlocked or no alewife across multiple temperature and resource treatments. Our results are inconsistent with a response to size-selective predation but are better explained as an adaptation to colder temperatures and shorter periods of development (countergradient variation) mediated by seasonal alewife predation.

  11. Measurement error associated with surveys of fish abundance in Lake Michigan

    USGS Publications Warehouse

    Krause, Ann E.; Hayes, Daniel B.; Bence, James R.; Madenjian, Charles P.; Stedman, Ralph M.

    2002-01-01

    In fisheries, imprecise measurements in catch data from surveys adds uncertainty to the results of fishery stock assessments. The USGS Great Lakes Science Center (GLSC) began to survey the fall fish community of Lake Michigan in 1962 with bottom trawls. The measurement error was evaluated at the level of individual tows for nine fish species collected in this survey by applying a measurement-error regression model to replicated trawl data. It was found that the estimates of measurement-error variance ranged from 0.37 (deepwater sculpin, Myoxocephalus thompsoni) to 1.23 (alewife, Alosa pseudoharengus) on a logarithmic scale corresponding to a coefficient of variation = 66% to 156%. The estimates appeared to increase with the range of temperature occupied by the fish species. This association may be a result of the variability in the fall thermal structure of the lake. The estimates may also be influenced by other factors, such as pelagic behavior and schooling. Measurement error might be reduced by surveying the fish community during other seasons and/or by using additional technologies, such as acoustics. Measurement-error estimates should be considered when interpreting results of assessments that use abundance information from USGS-GLSC surveys of Lake Michigan and could be used if the survey design was altered. This study is the first to report estimates of measurement-error variance associated with this survey.

  12. Evaluation of a chinook salmon (Oncorhynchus tshawytscha) bioenergetics model

    USGS Publications Warehouse

    Madenjian, Charles P.; O'Connor, Daniel V.; Chernyak, Sergei M.; Rediske, Richard R.; O'Keefe, James P.

    2004-01-01

    We evaluated the Wisconsin bioenergetics model for chinook salmon (Oncorhynchus tshawytscha) in both the laboratory and the field. Chinook salmon in laboratory tanks were fed alewife (Alosa pseudoharengus), the predominant food of chinook salmon in Lake Michigan. Food consumption and growth by chinook salmon during the experiment were measured. To estimate the efficiency with which chinook salmon retain polychlorinated biphenyls (PCBs) from their food in the laboratory, PCB concentrations of the alewife and of the chinook salmon at both the beginning and end of the experiment were determined. Based on our laboratory evaluation, the bioenergetics model was furnishing unbiased estimates of food consumption by chinook salmon. Additionally, from the laboratory experiment, we calculated that chinook salmon retained 75% of the PCBs contained within their food. In an earlier study, assimilation rate of PCBs to chinook salmon from their food in Lake Michigan was estimated at 53%, thereby suggesting that the model was substantially overestimating food consumption by chinook salmon in Lake Michigan. However, we concluded that field performance of the model could not be accurately assessed because PCB assimilation efficiency is dependent on feeding rate, and feeding rate of chinook salmon was likely much lower in our laboratory tanks than in Lake Michigan.

  13. Comparative recruitment dynamics of Alewife and Bloater in Lakes Michigan and Huron

    USGS Publications Warehouse

    Collingsworth, Paris D.; Bunnell, David B.; Madenjian, Charles P.; Riley, Stephen C.

    2014-01-01

    The predictive power of recruitment models often relies on the identification and quantification of external variables, in addition to stock size. In theory, the identification of climatic, biotic, or demographic influences on reproductive success assists fisheries management by identifying factors that have a direct and reproducible influence on the population dynamics of a target species. More often, models are constructed as one-time studies of a single population whose results are not revisited when further data become available. Here, we present results from stock recruitment models for Alewife Alosa pseudoharengus and Bloater Coregonus hoyi in Lakes Michigan and Huron. The factors that explain variation in Bloater recruitment were remarkably consistent across populations and with previous studies that found Bloater recruitment to be linked to population demographic patterns in Lake Michigan. Conversely, our models were poor predictors of Alewife recruitment in Lake Huron but did show some agreement with previously published models from Lake Michigan. Overall, our results suggest that external predictors of fish recruitment are difficult to discern using traditional fisheries models, and reproducing the results from previous studies may be difficult particularly at low population sizes.

  14. A multispecies statistical age-structured model to assess predator-prey balance: application to an intensively managed Lake Michigan pelagic fish community

    USGS Publications Warehouse

    Tsehaye, Iyob; Jones, Michael L.; Bence, James R.; Brenden, Travis O.; Madenjian, Charles P.; Warner, David M.

    2014-01-01

    Using a Bayesian model fitting approach, we developed a multispecies statistical catch-at-age model to assess trade-offs between predatory demands and prey productivities, focusing on the Lake Michigan pelagic fish community. We assessed these trade-offs in terms of predation mortalities and productivities of alewife (Alosa pseudoharengus) and rainbow smelt (Osmerus mordax) and functional responses of salmonines. Our predation mortality estimates suggest that salmonine consumption has been a major driver of historical fluctuations in prey abundance, with sharp declines in alewife abundance in the 1980s and 2000s coinciding with estimated increases in predation mortalities. While Chinook salmon (Oncorhynchus tshawytscha) were food limited during periods of low alewife abundance, other salmonines appeared to maintain a (near) maximum per-predator consumption across all observed prey densities, suggesting that feedback mechanisms are unlikely to help maintain a balance between predator consumption and prey productivity in Lake Michigan. This study demonstrates that a multispecies modeling approach that combines stock assessment methods with explicit consideration of predator–prey interactions could provide the basis for tactical decision-making from a broader ecosystem perspective.

  15. Fish community response to dam removal in a Maine coastal river tributary

    USGS Publications Warehouse

    Zydlewski, Joseph; Hogg, Robert S.; Coghlan Jr., Stephen M.; Gardner, Cory

    2016-01-01

    Sedgeunkedunk Stream, a third-order tributary to the Penobscot River in Maine, historically has supported several anadromous fishes including Atlantic Salmon Salmo salar, Alewife Alosa pseudoharengus, and Sea Lamprey Petromyzon marinus. Two small dams constructed in the 1800s reduced or eliminated spawning runs entirely. In 2009, efforts to restore marine–freshwater connectivity in the system culminated in removal of the lowermost dam (Mill Dam) providing access to 4.7 km of lotic habitat and unimpeded passage into the lentic habitat of Fields Pond. In anticipation of these barrier removals, we initiated a modified before-after-control-impact study, and monitored stream fish assemblages in fixed treatment and reference sites. Electrofishing surveys were conducted twice yearly since 2007. Results indicated that density, biomass, and diversity of the fish assemblage increased at all treatment sites upstream of the 2009 dam removal. No distinct changes in these metrics occurred at reference sites. We documented recolonization and successful reproduction of Atlantic Salmon, Alewife, and Sea Lamprey in previously inaccessible upstream reaches. These results clearly demonstrate that dam removal has enhanced the fish assemblage by providing an undisrupted stream gradient linking a small headwater lake and tributary with a large coastal river, its estuary, and the Atlantic Ocean.

  16. Estimates of lake trout (Salvelinus namaycush) diet in Lake Ontario using two and three isotope mixing models

    USGS Publications Warehouse

    Colborne, Scott F.; Rush, Scott A.; Paterson, Gordon; Johnson, Timothy B.; Lantry, Brian F.; Fisk, Aaron T.

    2016-01-01

    Recent development of multi-dimensional stable isotope models for estimating both foraging patterns and niches have presented the analytical tools to further assess the food webs of freshwater populations. One approach to refine predictions from these analyses is to include a third isotope to the more common two-isotope carbon and nitrogen mixing models to increase the power to resolve different prey sources. We compared predictions made with two-isotope carbon and nitrogen mixing models and three-isotope models that also included sulphur (δ34S) for the diets of Lake Ontario lake trout (Salvelinus namaycush). We determined the isotopic compositions of lake trout and potential prey fishes sampled from Lake Ontario and then used quantitative estimates of resource use generated by two- and three-isotope Bayesian mixing models (SIAR) to infer feeding patterns of lake trout. Both two- and three-isotope models indicated that alewife (Alosa pseudoharengus) and round goby (Neogobius melanostomus) were the primary prey items, but the three-isotope models were more consistent with recent measures of prey fish abundances and lake trout diets. The lake trout sampled directly from the hatcheries had isotopic compositions derived from the hatchery food which were distinctively different from those derived from the natural prey sources. Those hatchery signals were retained for months after release, raising the possibility to distinguish hatchery-reared yearlings and similarly sized naturally reproduced lake trout based on isotopic compositions. Addition of a third-isotope resulted in mixing model results that confirmed round goby have become an important component of lake trout diet and may be overtaking alewife as a prey resource.

  17. Comparison of thiaminase activity in fish using the radiometric and 4-nitrothiophenol colorimetric methods

    USGS Publications Warehouse

    Honeyfield, D.C.; Hanes, J.W.; Brown, L.; Kraft, C.E.; Begley, T.P.

    2010-01-01

    Thiaminase induced thiamine deficiency occurs in fish, humans, livestock and wild animals. A non-radioactive thiaminase assay was described in 2007, but a direct comparison with the radioactive 14C-thiamine method which has been in use for more than 30years has not been reported. The objective was to measure thiaminase activity in forage fish (alewife Alosa pseudoharengus, rainbow smelt Osmerus mordax, and slimy sculpin Cottus cognatus) consumed by predators that manifest thiamine deficiency using both methods. Modifications were made to the colorimetric assay to improve repeatability. Modification included a change in assay pH, enhanced sample clean-up, constant assay temperature (37??C), increase in the concentration of 4-nitrothiophenol (4NTP) and use of a spectrophotometer fitted with a 0.2cm cell. A strong relationship between the two assays was found for 51 alewife (R2=0.85), 36 smelt (R2=0.87) and 20 sculpin (R2=0.82). Thiaminase activity in the colorimetric assay was about 1000 times higher than activity measured by the radioactive method. Application of the assay to fish species from which no thiaminase activity has previously been reported resulted in no 4NTP thiaminase activity being found in bloater Coregonus hoyi, lake trout Salvelinus namaycusch, steelhead trout Oncorhynchus mykiss or Chinook salmon Oncorhynchus tshawytscha. In species previously reported to contain thiaminase, 4NTP thiaminase activity was measured in bacteria Paenibacillus thiaminolyticus, gizzard shad Dorosoma cepedianum, bracken fern Pteridium aquilinum, quagga mussel Dreissena bugensis and zebra mussels D. polymorpha. ?? 2010.

  18. Great lakes prey fish populations: a cross-basin overview of status and trends based on bottom trawl surveys, 1978-2012

    USGS Publications Warehouse

    Gorman, Owen T.

    2012-01-01

    The assessment of prey fish stocks in the Great Lakes have been conducted annually with bottom trawls since the 1970s by the Great Lakes Science Center, sometimes assisted by partner agencies. These stock assessments provide data on the status and trends of prey fish that are consumed by important commercial and recreational fishes. Although all these annual surveys are conducted using bottom trawls, they differ among the lakes in the proportion of the lake covered, seasonal timing, bottom trawl gear used, and the manner in which the trawl is towed (across or along bottom contours). Because each assessment is unique in one or more important aspects, direct comparison of prey fish catches among lakes is not straightforward. However, all of the assessments produce indices of abundance or biomass that can be standardized to facilitate comparisons of status and trends across all the Great Lakes. In this report, population indices were standardized to the highest value for a time series within each lake for the following principal prey species: cisco (Coregonus artedi), bloater (C. hoyi), rainbow smelt (Osmerus mordax), and alewife (Alosa pseudoharengus). Indices were also provided for round goby (Neogobius melanostomus), an invasive fish that has proliferated throughout the basin over the past 18 years. These standardized indices represent the best available long-term indices of relative abundance for these fishes across all of the Great Lakes. In this report, standardized indices are presented in graphical form along with synopses to provide a short, informal cross-basin summary of the status and trends of principal prey fishes. In keeping with this intent, tables, references, and a detailed discussion were omitted.

  19. Fish losses to double-crested cormorant predation in Eastern Lake Ontario, 1992-97

    USGS Publications Warehouse

    Ross, Robert M.; Johnson, James H.

    1999-01-01

    We examined 4,848 regurgitated digestive pellets of double-crested cormorants (Phalacrocorax auritus) over a 6-year period (1992–97) to estimate annual predation on sport and other fishes in the eastern basin of Lake Ontario. We found more than 51,000 fish of 28 species. Using a model that incorporates annual colony nest counts; fledgling production rates; adult, immature, and young-of-year residence times (seasonal); estimates of mean number of fish per pellet and mean fish size; and a fecal pathway correction factor (4.0 percent), we estimate total annual number of fish consumed by cormorants in the eastern basin of Lake Ontario to range from 37 million to 128 million fish for 1993–97. This fish loss equates to an estimated 0.93 million to 3.21 million kg (mean 2.07 million kg) of fish consumed per year, principally alewife (Alosa pseudoharengus, 42.3 percent) and yellow perch (Perca flavescens, 18.4 percent). Forage fish (alewife, cyprinids, trout-perch [Percopsis omiscomaycus], and other minor components) accounted for 65 percent of the diet, and panfish contributed 34 percent of the diet for the 5-year period. Game fish were minor components of the diet, in view of an average estimated annual consumption of 900,000 smallmouth bass (Micropterus dolomieui, 1.1 percent) and 168,000 salmonines (mostly lake trout, Salvelinus namaycush, 0.2 percent). Cormorant predation on lake trout fingerlings stocked in May 1993 and June 1994 was estimated through the use of coded wire tag recoveries from pellets collected on Little Galloo Island 1 and 4 days after stocking events. We estimated losses of 13.6 percent and 8.8 percent, respectively, of the fish stocked for the two events, an average of 11.2 percent. Such losses may be reduced through alteration of existing stocking practices.

  20. Broadband acoustic backscatter and high-resolution morphology of fish: Measurement and modeling

    NASA Astrophysics Data System (ADS)

    Reeder, D. Benjamin; Jech, J. Michael; Stanton, Timothy K.

    2004-08-01

    Broadband acoustic backscattering measurements, advanced high-resolution imaging of fish morphology using CT scans and phase-contrast x rays (in addition to traditional x rays), and associated scattering modeling using the images have been conducted involving alewife (Alosa pseudoharengus), a swimbladder-bearing fish. A greater-than-octave bandwidth (40-95 kHz) signal was used to insonify live, individual, adult alewife that were tethered while being rotated in 1-deg increments over all angles in two planes of rotation (lateral and dorsal/ventral). These data, in addition to providing the orientation dependence of the scattering over a continuous band of frequencies, were also used (after pulse compression) to identify dominant scattering features of the fish (including the skull and swimbladder). The x-ray and CT scan images of the swimbladder were digitized and incorporated into two scattering models: (1) Kirchhoff-ray mode (KRM) model [Clay and Horne, J. Acoust. Soc. Am. 96, 1661-1668 (1994)] and (2) conformal-mapping-based Fourier matching method (FMM), which has recently been extended to finite-length bodies [Reeder and Stanton, J. Acoust. Soc. Am. 116. 729-746 (2004)]. Comparisons between the scattering predictions and data demonstrate the utility of the CT scan imagery for use in scattering models, as it provided a means for rapidly and noninvasively measuring the fish morphology in three dimensions and at high resolution. In addition to further validation of the KRM model, the potential of the new FMM formulation was demonstrated, which is a versatile approach, valid over a wide range of shapes, all frequencies and all angles of orientation.

  1. Shifts in the diet of Lake Ontario alewife in response to ecosystem change

    USGS Publications Warehouse

    Stewart, T.J.; Sprules, W.G.; O'Gorman, R.

    2009-01-01

    In the 1990s, the Lake Ontario ecosystem was dramatically altered due to continued invasions of exotic species including dreissenid mussels and predatory cladocerans. We describe the diet and biomass of prey in the stomachs of adult (≥ 109 mm TL) and sub-adult (Alosa pseudoharengus) in 2004 and 2005 across seasons and depths and compare our results to data from 1972 to 1988. During 2004 and 2005, adult alewife consumed primarily zooplankton prey at bottom depth zones Mysis at bottom depth zones > 70 m. Mysis dominated the diets of adult alewife in all seasons except during the summer of 2004 when zooplankton dominated. Mysis dominated the diets of sub-adult alewife during early and late spring and zooplankton dominated the diets in summer and fall. Bythotrephes and Cercopagis were observed in the diets of both sub-adult and adult alewife. Diporeia was observed only rarely in adult alewife diets. The biomass of prey in alewife stomachs varied seasonally and increased with bottom depth for adult alewife. Alewife diets in 2004–2005 differed from those in 1972 and 1988 with an increase in the prevalence of Mysis, and a decline in the prevalence of zooplankton. The biomass of prey in adult alewife stomachs declined in 2004 and 2005 compared to 1972 and 1988, at bottom depth zones 70 m suggesting reduced food availability closer to shore. We hypothesize that consumption levels at the shallower depth zones, as indicated by very low biomass of prey in alewife stomachs, may not be sufficient to sustain alewife growth. The increased prevalence of Mysis and common occurrence of predatory cladocerans in the diet of alewife means that alewife have shifted to a higher trophic position.

  2. A shift in bloater consumption in Lake Michigan between 1993 and 2011 and its effects on Diporeia and Mysis prey

    USGS Publications Warehouse

    Pothoven, Steven A.; Bunnell, David B.

    2016-01-01

    Bioenergetics modeling was used to determine individual and population consumption by Bloater Coregonus hoyi in Lake Michigan during three time periods with variable Bloater density: 1993–1996 (high), 1998–2002 (intermediate), and 2009–2011 (low). Despite declines in Bloater abundance between 1993 and 2011, our results did not show any density-dependent compensatory response in annual individual consumption, specific consumption, or proportion of maximum consumption consumed. Diporeia spp. accounted for a steadily decreasing fraction of annual consumption, and Bloater were apparently unable to eat enough Mysis diluviana or other prey to account for the loss of Diporeia in the environment. The fraction of production of both Diporeia and Mysis that was consumed by the Bloater population decreased over time so that the consumption-to-production ratio for Diporeia + Mysis was 0.74, 0.26, and 0.14 in 1993–1996, 1998–2002, and 2009–2011, respectively. Although high Bloater numbers in the 1980s to 1990s may have had an influence on populations of Diporeia, Bloater were not the main factor driving Diporeia to a nearly complete disappearance because Diporeia continued to decline when Bloater predation demands were lessening. Thus, there appears to be a decoupling in the inverse relationship between predator and prey abundance in Lake Michigan. Compared with Alewife Alosa pseudoharengus, the other dominant planktivore in the lake, Bloater have a lower specific consumption and higher gross conversion efficiency (GCE), indicating that the lake can support a higher biomass of Bloater than Alewife. However, declines in Bloater GCE since the 1970s and the absence of positive responses in consumption variables following declines in abundance suggest that productivity in Lake Michigan might not be able to support the same biomass of Bloater as in the past.

  3. Bathythermal habitat use by strains of Great Lakes- and Finger Lakes-origin lake trout in Lake Huron after a change in prey fish abundance and composition

    USGS Publications Warehouse

    Bergstedt, Roger A.; Argyle, Ray L.; Krueger, Charles C.; Taylor, William W.

    2012-01-01

    A study conducted in Lake Huron during October 1998–June 2001 found that strains of Great Lakes-origin (GLO) lake trout Salvelinus namaycush occupied significantly higher temperatures than did Finger Lakes-origin (FLO; New York) lake trout based on data from archival (or data storage) telemetry tags that recorded only temperature. During 2002 and 2003, we implanted archival tags that recorded depth as well as temperature in GLO and FLO lake trout in Lake Huron. Data subsequently recorded by those tags spanned 2002–2005. Based on those data, we examined whether temperatures and depths occupied by GLO and FLO lake trout differed during 2002–2005. Temperatures occupied during those years were also compared with occupied temperatures reported for 1998–2001, before a substantial decline in prey fish biomass. Temperatures occupied by GLO lake trout were again significantly higher than those occupied by FLO lake trout. This result supports the conclusion of the previous study. The GLO lake trout also occupied significantly shallower depths than FLO lake trout. In 2002–2005, both GLO and FLO lake trout occupied significantly lower temperatures than they did in 1998–2001. Aside from the sharp decline in prey fish biomass between study periods, the formerly abundant pelagic alewife Alosa pseudoharengus virtually disappeared and the demersal round goby Neogobius melanostomus invaded the lake and became locally abundant. The lower temperatures occupied by lake trout in Lake Huron during 2002–2005 may be attributable to changes in the composition of the prey fish community, food scarcity (i.e., a retreat to cooler water could increase conversion efficiency), or both.

  4. Variations of thiaminase I activity pH dependencies among typical Great Lakes forage fish and Paenibacillus thiaminolyticus.

    USGS Publications Warehouse

    Zajicek, J.L.; Brown, L.; Brown, S.B.; Honeyfield, D.C.; Fitzsimons, J.D.; Tillitt, D.E.

    2009-01-01

    The source of thiaminase in the Great Lakes food web remains unknown. Biochemical characterization of the thiaminase I activities observed in forage fish was undertaken to provide insights into potential thiaminase sources and to optimize catalytic assay conditions. We measured the thiaminase I activities of crude extracts from five forage fish species and one strain of Paenibacillus thiaminolyticus over a range of pH values. The clupeids, alewife Alosa pseudoharengus and gizzard shad Dorosoma cepedianum, had very similar thiaminase I pH dependencies, with optimal activity ranges (> or = 90% of maximum activity) between pH 4.6 and 5.5. Rainbow smelt Osmerus mordax and spottail shiner Notropis hudsonius had optimal activity ranges between pH 5.5-6.6. The thiaminase I activity pH dependence profile of P. thiaminolyticus had an optimal activity range between pH 5.4 and 6.3, which was similar to the optimal range for rainbow smelt and spottail shiners. Incubation of P. thiaminolyticus extracts with extracts from bloater Coregonus hoyi (normally, bloaters have little or no detectable thiaminase I activity) did not significantly alter the pH dependence profile of P. thiaminolyticus-derived thiaminase I, such that it continued to resemble that of the rainbow smelt and spottail shiner, with an apparent optimal activity range between pH 5.7 and 6.6. These data are consistent with the hypothesis of a bacterial source for thiaminase I in the nonclupeid species of forage fish; however, the data also suggest different sources of thiaminase I enzymes in the clupeid species.

  5. Evaluating the importance of abiotic and biotic drivers on Bythotrephes biomass in Lakes Superior and Michigan

    USGS Publications Warehouse

    Keeler, Kevin M.; Bunnell, David B.; Diana, James S.; Adams, Jean V.; Mychek-Londer, Justin G.; Warner, David M.; Yule, Daniel; Vinson, Mark

    2015-01-01

    The ability of planktivorous fishes to exert top-down control on Bythotrephes potentially has far-reaching impacts on aquatic food-webs, given previously described effects of Bythotrephes on zooplankton communities. We estimated consumption of Bythotrephes by planktivorous and benthivorous fishes, using bioenergetics and daily ration models at nearshore (18 m), intermediate (46 m), and offshore (110 m) depths along one western Lake Superior transect (April, and September-November) and two northern Lake Michigan transects (April, July, September). In Lake Superior, consumption (primarily by cisco Coregonus artedi) exceeded Bythotrephes production at all offshore sites in September-November (up to 396% of production consumed) and at the intermediate site in November (842%) with no evidence of consumption nearshore. By comparing Bythotrephes biomass following months of excessive consumption, we conservatively concluded that top-down control was evident only at the offshore site during September-October. In Lake Michigan, consumption by fishes (primarily alewife Alosa pseudoharengus) exceeded production at nearshore sites (up to 178%), but not in deeper sites (< 15%). Evidence for top-down control in the nearshore was not supported, however, as Bythotrephes never subsequently declined. Using generalized additive models, temperature, and not fish consumption, not zooplankton prey density, best explained variability in Bythotrephes biomass. The non-linear pattern revealed Bythotrephes to increase with temperature up to 16 °C, and then decline between 16 and 23 °C. We discuss how temperature likely has direct negative impacts on Bythotrephes when temperatures near 23 °C, but speculate that predation also contributes to declining biomass when temperatures exceed 16 °C.

  6. Temporal trends of young-of-year fishes in Lake Erie and comparison of diel sampling periods

    USGS Publications Warehouse

    Stapanian, M.A.; Bur, M.T.; Adams, J.V.

    2007-01-01

    We explored temporal trends of young-of-year (YOY) fishes caught in bottom trawl hauls at an established offshore monitoring site in Lake Erie in fall during 1961–2001. Sampling was conducted during morning, afternoon, and night in each year. Catches per hour (CPH) of alewife (Alosa pseudoharengus) YOY were relatively low and exhibited no temporal trend. This result was consistent with the species’ intolerance to Lake Erie’s adverse winter water temperatures. Gizzard shad (Dorosoma cepedianum) YOY decreased sharply after 1991, which was consistent with recent oligotrophication of the lake. Following the establishment in 1979 and rapid increase of white perch (Morone americana) YOY, white bass (Morone chrysops) and freshwater drum (Aplodinotus grunniens) YOY decreased. Trout-perch (Percopsis omiscomaycus) YOY decreased during 1986–1991, but recovered to previous levels during 1991–2001. The recovery coincided with the resurgence of mayflies (Ephemoptera) in the lake. CPH of spottail shiner (Notropis hudsonius) and emerald shiner (N. atherinoides) YOY exhibited no temporal trend between 1961 and the late 1970s to early 1980s. CPH of yellow perch (Perca flavescens) YOY decreased during 1961–1988, and walleye (Sander vitreum) YOY increased overall during the time series. These observations were consistent with published studies of adults in the region. CPH of 4 of the 10 species of YOY considered were greatest during night. CPH for walleye YOY was higher in the morning than in the afternoon, but there was no significant difference between night and morning abundances. The results suggest that (1) CPH of YOY fishes may be a useful monitoring tool for Lake Erie, and (2) offshore monitoring programs that do not include night sampling periods may underestimate recruitment for several common species.

  7. Ichthyoplankton assemblages of coastal west-central Lake Erie and associated habitat characteristics

    USGS Publications Warehouse

    McKenna, J.E.; Davis, B.M.; Fabrizio, M.C.; Savino, J.F.; Todd, T.N.; Bur, M.

    2008-01-01

    Early life stage survival often determines fish cohort strength and that survival is affected by habitat conditions. The structure and dynamics of ichthyoplankton assemblages can tell us much about biodiversity and fish population dynamics, but are poorly understood in nearshore areas of the Great Lakes, where most spawning and nursery habitats exist. Ichthyoplankton samples were collected with a neuston net in waters 2-13 m deep weekly or biweekly from mid-April through August, during 3 years (2000-2002) as part of a study of fish assemblages in west-central Lake Erie. A suite of abiotic variables was simultaneously measured to characterize habitat. Cluster and ordination analyses revealed several distinct ichthyoplankton assemblages that changed seasonally. A lake whitefish (Coregonus clupeaformis) dominated assemblage appeared first in April. In May, assemblages were dominated by several percid species. Summer assemblages were overwhelmingly dominated by emerald shiner (Notropis atherinoides), with large gizzard shad (Dorosoma cepedianum) and alewife (Alosa pseudoharengus) components. This seasonal trend in species assemblages was also associated with increasing temperature and water clarity. Water depth and drift processes may also play a role in structuring these assemblages. The most common and widely distributed assemblages were not associated with substratum type, which we characterized as either hard or soft. The timing of hatch and larval growth separated the major groups in time and may have adaptive significance for the members of each major assemblage. The quality and locations (with reference to lake circulation) of spawning and nursery grounds may determine larval success and affect year class strength.

  8. Lake trout population dynamics in the Northern Refuge of Lake Michigan: implications for future rehabilitation

    USGS Publications Warehouse

    Madenjiana, Charles P.; DeSorcie, Timothy J.

    2010-01-01

    The Northern Refuge was established in 1985 as part of the lake trout Salvelinus namaycush rehabilitation effort for Lake Michigan. To evaluate progress toward lake trout rehabilitation in the Northern Refuge, we conducted annual (1991–2008) gill-net surveys in the fall to assess the adult population and beam trawl surveys in the spring to assess naturally reproduced age-0 lake trout. Our criteria for evaluating progress included the density of “wild” age-0 fish within the Northern Refuge, the proportion of wild fish within the adult population, density of spawners, adult survival, growth, and wounding rate by sea lampreys Petromyzon marinus. No wild age-0 lake trout were caught in the Northern Refuge during 1991–2008. Overall, wild lake trout did not recruit to the adult population to any detectable degree. The mean density of spawning lake trout decreased from 45 fish·305 m of gill net−1·d−1 during 1991–1999 to only 4 fish·305 m−1·d−1 during 2000–2008. Although the sea lamprey wounding rate more than doubled between these two time periods, catch curve analysis revealed that mortality of adult lake trout actually decreased between the two periods. Therefore, the 90% decrease in abundance of spawning lake trout between the two periods could not be attributed to increased sea lamprey predation but instead was probably due in part to the reduced lake trout stocking rate during 1995–2005. The paucity of natural reproduction in the Northern Refuge during 1991–2008 most likely resulted from alewife Alosa pseudoharengus interference with lake trout reproduction and from the relatively low lake trout spawner density during 2000–2008. Our results suggest that the annual stocking rate of lake trout yearlings should be increased to at least 250,000 fish/reef to achieve greater densities of spawners.

  9. Misapplied survey data and model uncertainty result in incorrect conclusions about the role of predation on alewife population dynamics in Lake Huron: a comment on He et al. (2015)

    USGS Publications Warehouse

    Riley, Stephen C.; Dunlop, Erin S.

    2016-01-01

    Drastic recent and ongoing changes to fish populations and food webs in the Great Lakes have been well-described (Riley et al. 2008; Barbiero et al. 2009; Nalepa et al. 2009; Fahnenstiel et al. 2010;Evans et al. 2011; Gobin et al. 2015), and uncertainty regarding their potential effects on fisheries has caused concern among scientists and fishery managers (e.g., Dettmers et al. 2012). In particular, the relative importance of “bottom-up” (e.g., lower trophic level changes) versus “top-down” (e.g., predation) factors to fish community changes in the Great Lakes have been widely debated (e.g.,Barbiero et al. 2011; Eshenroder and Lantry 2012; Bunnell et al. 2014). In Lake Huron, recent ecosystem changes have been particularly profound, and populations of alewife (Alosa pseudoharengus), an offshore pelagic prey fish, collapsed in 2003 and have yet to recover (Riley et al. 2008, 2014). He et al. (2015) recently used a series of linked ecological models to assess the role of predation in the dynamics of the offshore prey fish community in Lake Huron. While we believe that they provide a novel method for combining bioenergetics and stock assessment modeling, we question the validity of their conclusions because of the misapplication of survey data and the lack of critical interpretation of their modeling efforts. Here we describe how He et al. (2015) have misapplied bottom trawl data from Lake Huron, and we provide examples of how this has resulted in erroneous conclusions regarding the importance of predation to the population dynamics and collapse of alewife in Lake Huron.

  10. Sustainability of hatchery-dependent salmonine fisheries in Lake Ontario: The conflict between predator demand and predator supply

    USGS Publications Warehouse

    Jones, Michael L.; Koonce, Joseph F.; O'Gorman, Robert

    1993-01-01

    The offshore fish community of Lake Ontario is presently dominated by intensively managed, nonnative species: Alewife Alosa pseudoharengus and rainbow smelt Osmerus mordax at the planktivore level and stocked salmonines at the piscivore level. Salmonine stocking rates per unit area of Lake Ontario are the highest in the Great Lakes, and fishery managers are concerned about the sustainability of the fishery under present stocking policies, particularly with the recent collapse of the Lake Michigan fishery for chinook salmon Oncorhynchus tshawytscha. In this paper, we describe and present the results of a simulation model that integrates predator demand estimates derived from bioenergetics, prey and predator population dynamics, and a predation model based on the multiple-species functional response, Model reconstructions of historical alewife biomass trends and salmonine diets corresponded reasonably well with existing data for the period 1978–1992. The simulations suggest that current predator demand does not exceed the threshold beyond which alewife biomass cannot be sustained, but they indicate that the sustainability of the prey fish community is extremely sensitive to fluctuations in overwinter survival of alewife; an additional mortality of 25% in a single winter would be sufficient to cause the collapse of the alewife population. The model includes a number of assumptions and simplifications with a limited empirical basis; better estimates of salmonine survival rates, an evaluation of the importance of spatial and temporal interactions among predators and prey, and incorporation of the effects of recently observed declines in system productivity at lower trophic levels would significantly increase confidence in the model's projections.

  11. Laboratory evaluation of a lake trout bioenergetics model

    USGS Publications Warehouse

    Madenjian, Charles P.; O'Connor, Daniel V.

    1999-01-01

    Lake trout Salvelinus namaycush, aged 3 and 6 years and with average weights of 700 and 2,000 g, were grown in laboratory tanks for up to 407 d under a thermal regime similar to that experienced by lake trout in nearshore Lake Michigan. Lake trout were fed alewifeAlosa pseudoharengus and rainbow smelt Osmerus mordax, prey typical of lake trout in Lake Michigan. Of the 120 lake trout used in the experiment, 40 were fed a low ration (0.25% of their body weight per day), 40 were fed a medium ration (0.5% of their body weight per day), and 40 were fed a high ration (ad libitum). We measured consumption and growth, and we compared observed consumption with that predicted by the Wisconsin bioenergetics model. For lake trout fed the medium ration, model predictions for monthly consumption were unbiased. Moreover, predicted cumulative consumption by medium-ration lake trout for the entire experiment (320 d for smaller lake trout and 407 d for larger lake trout) agreed quite well with observed cumulative consumption; predictions were as close as within 0.1 to 5.2% of observed cumulative consumption. Even so, the model consistently overestimated consumption by low-ration fish and underestimated consumption by high-ration fish. The bias was significant in both cases, but was more severe for the low-ration trout. Because the low-ration and high-ration regimes were probably unrealistic for lake trout residing in Lake Michigan and because the model fit our laboratory data rather well for medium-ration trout, we conclude that applying the Wisconsin bioenergetics model to the Lake Michigan lake trout population in order to estimate the amount of prey fish consumed by lake trout each year is appropriate.

  12. Evaluation of methods for identifying spawning sites and habitat selection for alosines

    USGS Publications Warehouse

    Harris, Julianne E.; Hightower, Joseph E.

    2010-01-01

    Characterization of riverine spawning habitat is important for the management and restoration of anadromous alosines. We examined the relative effectiveness of oblique plankton tows and spawning pads for collecting the eggs of American shad Alosa sapidissima, hickory shad A. mediocris, and “river herring” (a collective term for alewife A. pseudoharengus and blueback herring A. aestivalis) in the Roanoke River, North Carolina. Relatively nonadhesive American shad eggs were only collected by plankton tows, whereas semiadhesive hickory shad and river herring eggs were collected by both methods. Compared with spawning pads, oblique plankton tows had higher probabilities of collecting eggs and led to the identification of longer spawning periods. In assumed spawning areas, twice-weekly plankton sampling for 15 min throughout the spawning season had a 95% or greater probability of collecting at least one egg for all alosines; however, the probabilities were lower in areas with more limited spawning. Comparisons of plankton tows, spawning pads, and two other methods of identifying spawning habitat (direct observation of spawning and examination of female histology) suggested differences in effectiveness and efficiency. Riverwide information on spawning sites and timing for all alosines is most efficiently obtained by plankton sampling. Spawning pads and direct observations of spawning are the best ways to determine microhabitat selectivity for appropriate species, especially when spawning sites have previously been identified. Histological examination can help determine primary spawning sites but is most useful when information on reproductive biology and spawning periodicity is also desired. The target species, riverine habitat conditions, and research goals should be considered when selecting methods with which to evaluate alosine spawning habitat.

  13. Anadromous sea lampreys recolonize a Maine coastal river tributary after dam removal

    USGS Publications Warehouse

    Hogg, Robert; Coghlan Jr., Stephen M.; Zydlewski, Joseph

    2013-01-01

    Sedgeunkedunk Stream, a third-order tributary to the Penobscot River, Maine, historically supported several anadromous fishes, including the Atlantic Salmon Salmo salar, AlewifeAlosa pseudoharengus, and Sea Lamprey Petromyzon marinus. However, two small dams constructed in the 1800s reduced or eliminated spawning runs entirely. In 2009, efforts to restore marine–freshwater connectivity in the system culminated with removal of the lowermost dam, thus providing access to an additional 4.6 km of lotic habitat. Because Sea Lampreys utilized accessible habitat prior to dam removal, they were chosen as a focal species with which to quantify recolonization. During spawning runs of 2008–2011 (before and after dam removal), individuals were marked with PIT tags and their activity was tracked with daily recapture surveys. Open-population mark–recapture models indicated a fourfold increase in the annual abundance of spawning-phase Sea Lampreys, with estimates rising from 59±4 () before dam removal (2008) to 223±18 and 242±16 after dam removal (2010 and 2011, respectively). Accompanying the marked increase in annual abundance was a greater than fourfold increase in nesting sites: the number of nests increased from 31 in 2008 to 128 and 131 in 2010 and 2011, respectively. During the initial recolonization event (i.e., in 2010), Sea Lampreys took 6 d to move past the former dam site and 9 d to expand into the furthest upstream reaches. Conversely, during the 2011 spawning run, Sea Lampreys took only 3 d to penetrate into the upstream reaches, thus suggesting a potential positive feedback in which larval recruitment into the system may have attracted adult spawners via conspecific pheromone cues. Although more research is needed to verify the migratory pheromone hypothesis, our study clearly demonstrates that small-stream dam removal in coastal river systems has the potential to enhance recovery of declining anadromous fish populations.

  14. Diet shifts by planktivorous and benthivorous fishes in northern Lake Michigan in response to ecosystem changes

    USGS Publications Warehouse

    Bunnell, David B.; Davis, Bruce M.; Chriscinske, Margret Ann; Keeler, Kevin M.; Mychek-Londer, Justin G.

    2015-01-01

    In Lake Michigan, diets of planktivorous and benthivorous fishes have varied over the past decades, in part owing to food web changes. To update diet information and compare them to a similar effort in 1994–1995, we analyzed the diets of seven benthivorous and planktivorous fish species collected along two northern Lake Michigan transects that spanned nearshore (18 m), intermediate (46 m), and offshore (91, 110, 128 m) bottom depths during spring, summer, and autumn of 2010. Calanoid copepods (e.g., Limnocalanus macrurus, Leptodiaptomus sicilis, and Senecella calanoides) comprised a majority of the diets in at least one season for all sizes of alewife (Alosa pseudoharengus), bloater (Coregonus hoyi), and rainbow smelt (Osmerus mordax). Similarly, Mysis diluviana was the highest proportion in at least one season for large sizes of alewife, bloater, and rainbow smelt, as well as slimy sculpin (Cottus cognatus) and deepwater sculpin (Myoxocephalus thompsonii). The diets of the remaining two species, ninespine stickleback (Pungitius pungitius) and round goby (Neogobius melanostomus), were dominated by herbivorous cladocerans or dreissenid mussels, respectively. Interspecific diet overlap was minimal at 18 and 46 m. In offshore waters, however, overlap was relatively high, driven by frequent consumption of Mysis. Relative to 1994–1995, 2010 diets revealed increased feeding on calanoid copepods and Mysis, with corresponding declining consumption of Diporeia spp. and herbivorous cladocerans. Relative diet weight was also higher in 1994–1995 than in 2010 for small and large bloater and both sculpin species. We hypothesize that the shifts in diets are reflective of community-level changes in invertebrate prey availability.

  15. Little Galloo Island, Lake Ontario: A review of nine years of double-crested cormorant diet and fish consumption information

    USGS Publications Warehouse

    Johnson, James H.; Ross, Robert M.; McCullough, Russ D.

    2002-01-01

    The diet of double-crested cormorants (Phalacrocorax auritus) on Little Galloo Island (LGI) in the eastern basin of Lake Ontario has been quantified since 1992. Over the past nine years considerable information has been generated on cormorant feeding ecology through the examination of approximately 12,000 pellets collected on LGI, where three distinct cormorant feeding periods, pre-chick, chick, and post-chick, are delineated by differences in diet composition and daily fish consumption. Yellow perch (Perca flavescens) were the major prey during pre-chick and post-chick feeding periods. Alewife (Alosa pseudoharengus), which move inshore to spawn in mid-June, dominated (>60%) cormorant diets during the chick feeding period. Mean daily fish consumption (14.6) during the pre-chick feeding period was significantly greater than during the chick feeding (9.3) or post-chick feeding (8.0) periods. The proportion of smallmouth bass (Micropterus dolomieu) in the diet increased over the season (0.8% to 7.2%), while the size of bass consumed declined (214 mm to 143 mm). Forage fish (mainly alewife, three-spine sticklebacks [Gasterosteus aculeatus] and minnows) comprised 58% of the diet of LGI cormorants, followed by panfish (37%) (yellow perch, pumpkinseed [Lepomis gibbosus], rock bass [Ambloplites rupestris]) and gamefish (5%) (mostly smallmouth bass). On the average LGI cormorants consumed about 32.8 million fish annually, weighing about 1.4 million kilograms. Cormorants from LGI consumed more biomass of smallmouth bass and yellow perch annually than is taken by sport (bass and yellow perch) and commercial (perch) fishermen.

  16. Does variation in the intensity and duration of predation drive evolutionary changes in senescence?

    PubMed

    Walsh, Matthew R; Whittington, Deirdre; Walsh, Melissa J

    2014-11-01

    The evolutionary theory of senescence predicts that increased rates of extrinsic mortality select for faster declines in fertility and survival with age. One predicted mechanism is that increased mortality favours alleles that enhance fitness early in life at the expense of survival or reproduction later in life (antagonistic pleiotropy). We tested these predictions in natural populations of Daphnia ambigua from lakes that vary in the severity and duration of fish predation. Daphnia are found in lakes with (i) anadromous alewife (Alosa pseudoharengus) that migrate between marine and freshwater, (ii) permanent landlocked alewife and (iii) no alewife. Daphnia are rare year-round in 'landlocked lakes' and are seasonally eliminated from the water column in 'anadromous lakes' due to the very strong predatory impact of anadromous alewife on populations of zooplankton. Previous work has also shown that intense seasonal bouts of predation by anadromous alewife has selected for increased allocation towards growth and reproduction in Daphnia found in lakes with anadromous alewife. Such variation in the risk of mortality and the expression of life-history traits early in life provides the raw materials to test the evolutionary theory of ageing. We reared replicate populations of Daphnia from all three lake types and quantified lifetime rates of offspring production and intrinsic survival. We found no differences in age-related declines in fertility or survival. Daphnia from anadromous lakes produced significantly more offspring throughout their lifetime despite no differences in life span or in the number of reproductive bouts compared with Daphnia from lakes with landlocked and no alewife. The lack of divergence in ageing contradicts the prediction that elevated mortality rates drive evolutionary shifts in ageing. We reconcile these results by considering the predictions of theoretical frameworks that incorporate feedbacks associated with increased mortality such as density

  17. Optimal swim speeds for traversing velocity barriers: An analysis of volitional high-speed swimming behavior of migratory fishes

    USGS Publications Warehouse

    Castro-Santos, T.

    2005-01-01

    Migrating fish traversing velocity barriers are often forced to swim at speeds greater than their maximum sustained speed (Ums). Failure to select an appropriate swim speed under these conditions can prevent fish from successfully negotiating otherwise passable barriers. I propose a new model of a distance-maximizing strategy for fishes traversing velocity barriers, derived from the relationships between swim speed and fatigue time in both prolonged and sprint modes. The model predicts that fish will maximize traversed distance by swimming at a constant groundspeed against a range of flow velocities, and this groundspeed is equal to the negative inverse of the slope of the swim speed-fatigue time relationship for each mode. At a predictable flow velocity, they should switch from the optimal groundspeed for prolonged mode to that for sprint mode. Data from six migratory fish species (anadromous clupeids: American shad Alosa sapidissima, alewife A. pseudoharengus and blueback herring A. aestivalis; amphidromous: striped bass Morone saxatilis; and potomodromous species: walleye (previously known as Stizostedion vitrium) and white sucker Catostomus commersonii) were used to explore the ability of fish to approximate the predicted distance-maximizing behaviors, as well as the consequences of deviating from the optima. Fish volitionally sprinted up an open-channel flume against fixed flow velocities of 1.5-4.5 m s-1, providing data on swim speeds and fatigue times, as well as their groundspeeds. Only anadromous clupeids selected the appropriate distance-maximizing groundspeed at both prolonged and sprint modes. The other three species maintained groundspeeds appropriate to the prolonged mode, even when they should have switched to the sprint optima. Because of this, these species failed to maximize distance of ascent. The observed behavioral variability has important implications both for distributional limits and fishway design.

  18. Species succession and fishery exploitation in the Great Lakes

    USGS Publications Warehouse

    Smith, Stanford H.

    1968-01-01

    The species composition of fish in the Great Lakes has undergone continual change since the earliest records. Some changes were caused by enrichment of the environment, but others primarily by an intensive and selective fishery for certain species. Major changes related to the fishery were less frequent before the late 1930's than in recent years and involved few species. Lake sturgeon (Acipenser fulvescens) were overexploited knowingly during the late 1800's because they interfered with fishing for preferred species; sturgeon were greatly reduced in all lakes by the early 1900's. Heavy exploitation accompanied sharp declines of lake herring (Leucichthys artedi) in Lake Erie during the 1920's and lake whitefish (Coregonus clupeaformis) in Lake Huron during the 1930's. A rapid succession of fish species in Lakes Huron, Michigan, and Superior that started about 1940 has been caused by selective predation by the sea lamprey (Petromyzon marinus) on native predatory species, and the resultant shifting emphasis of the fishery and species interaction as various species declined. Lake trout (Salvelinus namaycush) and burbot (Lota lota), the deepwater predators, were depleted first; this favored their prey, the chubs (Leucichthys spp.). The seven species of chubs were influenced differently according to differences in size. Fishing emphasis and predation by sea lampreys were selective for the largest species of chubs as lake trout and burbot declined. A single slow-growing chub, the bloater, was favored and increased, but as the large chubs declined the bloater was exploited by a new trawl fishery. The growth rate and size of the bloater increased, making it more vulnerable to conventional gillnet fishery and lamprey predation. This situation in Lakes Michigan and Huron favored the small alewife (Alosa pseudoharengus) which had recently become established in the upper Great Lakes, and the alewife increased rapidly and dominated the fish stocks of the lakes. The successive

  19. Lake trout status in the main basin of Lake Huron, 1973-2010

    USGS Publications Warehouse

    He, Ji X.; Ebener, Mark P.; Riley, Stephen C.; Cottrill, Adam; Kowalski, Adam; Koproski, Scott; Mohr, Lloyd; Johnson, James E.

    2012-01-01

    We developed indices of lake trout Salvelinus namaycush status in the main basin of Lake Huron (1973-2010) to understand increases in the relative abundance of wild year-classes during 1995-2010. Sea lamprey Petromyzon marinus wounds per 100 lake trout declined from 23.63 in 2000 to 5.86-10.64 in 2002-2010. The average age-7 lake trout catch per effort per recruitment (CPE/R; fish•305mof gill net-1•million stocked yearlings-1) increased from 0.56 for the 1973-1990 year-classes to 0.92 for the 1991-2001 year-classes. Total CPE (fish/305 m of gill net) declined from 16.4 fish in 1996 to 4.1 fish in 2010, but the percentage of age-5 and younger lake trout steadily decreased from more than 70% before 1996 to less than 10% by 2009. The modal age in gill-net catches increased from age 5 before 1996 to age 7 by 2005. The average adult CPE increased from 2.8 fish/305 m of gill net during 1978-1995 to 5.34 fish/305 m of gill net during 1996-2010. The 1995-2010 year-classes of wild fish weremore abundant than previous year-classes and were associated with the relatively high adult abundance during 1996-2010. Until the 2002 year-class, there was no decline in age-7 CPE/R; until 2008, there was no decline in adult CPE. Low survival of the 2002 and 2003 year-classes of stocked fish was related to the event of alewife Alosa pseudoharengus population collapse in 2003-2004. Lake trout in the main basin of Lake Huron are undergoing a transition from a hatchery stock to a wild stock, accompanied by an increased uncertainty in delayed recruitment. Future management should pay more attention to the protection of wild recruitment and the abundance of the spawning stock.

  20. Toxaphene congeners in the Canadian Great Lakes basin: temporal and spatial food web dynamics.

    PubMed

    Whittle, D M; Kiriluk, R M; Carswell, A A; Keir, M J; MacEachen, D C

    2000-01-01

    Samples of a top predator fish species, lake trout (Salvelinus namaycush) and predominant forage species including smelt (Osmerus mordax), alewife (Alosa pseudoharengus), slimy sculpin (Cottus cognatus), deepwater sculpin (Myoxocephalus quadricornis) and lake herring (Coregonus artedii) were, collected from throughout 4 of the 5 Great Lakes (Superior, Huron, Erie and Ontario) (Fig. 1). Lake trout were also collected from three isolated lake systems (Lakes Nipigon, Simcoe and Opeongo), all located within the basin. All the samples were analysed for body burdens of total toxaphene and 22 toxaphene congeners. In addition, from each of the Great Lakes sites samples of major invertebrate dietary items, which included Mysis relicta, Diporeia hoyi and plankton, were similarly analysed. Whole lake trout samples, archived at -80 degrees C, were reanalysed to determine historical trends of toxaphene congeners plus carbon and nitrogen stable isotope signatures. The Lake Superior food web consistently had the highest levels of total toxaphene of all the Great Lakes monitored. The primary source of toxaphene to Lake Superior has been identified as atmospheric transport and deposition from sites in the southern US, Mexico and Central America (Hoff, R.M., Strachan, W.M.J., Sweet, C.W., Chan, C.H., Shackelton, M., Bidleman, T.F., Brice, K.A., Burnison, D.A., Cussion, S., Gatz, D.F., Harlin, K., Schroeder, W.H., 1996. Atmospheric deposition of toxic chemicals to the Great Lakes: A review of data through 1994. Atmospheric Environ. 30, 3505-3527). Of the offsystem lakes surveyed. Lake Nipigon, situated due north of Lake Superior and with a Lake Basin area of about 6% of Lake Superior (Hendendorf, C.E., 1982. J. Great Lakes Res. 8(3), 379-412) had total toxaphene levels in lake trout equivalent to about 50% of those found in lake trout from Lake Superior. Temporal trend toxaphene congener analysis was conducted on archived whole fish samples collected over the period 1980 through to

  1. Factors of ecologic succession in oligotrophic fish communities of the Laurentian Great Lakes

    USGS Publications Warehouse

    Smith, Stanford H.

    1972-01-01

    Oligotrophic fish communities of the Great Lakes have undergone successive disruptions since the mid-1800s. Major contributing factors have been intensive selective fisheries, extreme modification of the drainage, invasion of marine species, and progressive physical–chemical changes of the lake environments. Lake Ontario was the first to be affected as its basin was settled and industrialized earliest, and it was the first to be connected by canals to the mid-Atlantic where the alewife (Alosa pseudoharengus) and sea lamprey (Petromyzon marinus) which ultimately became established in the Great Lakes were abundant. Oligotrophic fish communities were successively disrupted in Lakes Erie, Huron, Michigan, and Superior as the affects of population growth, industrialization, and marine invaders spread upward in the Laurentian drainage.The degree and sequence of response of families offish and species within families differed for each factor, but the sequence of change among families and species has been the same in response to each factor as it affected various lakes at different times. The ultimate result of the disruption of fish communities has been a reduction of productivity of oligotrophic species that ranges from extreme in Lake Ontario to moderate in Lake Superior, and which has reached a state of instability and rapid change in the upper three Great Lakes by the rnid-1900s similar to the situation in Lake Ontario in the mid-1800s. Since oligotrophic species (primarily salmonines, coregonines, and deepwater cottids) are the only kinds of fish that fully occupied the entire volume of the deepwater Great Lakes (Ontario, Huron, Michigan, and Superior), the fish biomass of these lakes has been reduced as various species declined or disappeared. In Lake Erie, which is shallow, and in the shallow bays of the deep lakes, oligotrophic species were replaced by mesotrophic species, primarily percids, which have successively increased and declined. All oligotrophic

  2. Thiamine Deficiency Complex Workshop final report: November 6-7, 2008, Ann Arbor, MI

    USGS Publications Warehouse

    Honeyfield, Dale C.; Tillitt, Donald E.; Riley, Stephen C.

    2008-01-01

    Fry mortality which was first observed in the late 1960s in Great Lakes salmonines and in Baltic Sea salmon in 1974 has now been linked to thiamine deficiency (historically referred to as Early Mortality Syndrome, or EMS and M74, respectively). Over the past 14 years significant strides have been made in our understanding of this perplexing problem. It is now known that thiamine deficiency causes embryonic mortality in these salmonids. Both overt mortality and secondary effects of thiamine deficiency are observed in juvenile and adult animals. Collectively the morbidity and mortality (fry and adult mortality, secondary metabolic and behavior affects in juveniles and adult fish) are referred to as Thiamine Deficiency Complex (TDC). A workshop was held in Ann Arbor, MI on 6-7 November 2008 that brought together 38 federal, state, provincial, tribal and university scientists to share information, present data and discuss the latest observations on thiamine status of aquatic animals with thiamine deficiency and the causative agent, thiaminase. Twenty presentations (13 oral and 7 posters) detailed current knowledge. In Lake Huron, low alewife Alosa pseudoharengus abundance has persisted and egg thiamine concentrations in salmonines continue to increase, along with evidence of natural reproduction in lake trout Salvelinus namaycush. Lake Michigan Chinook salmon Oncorhynchus tshawytscha appear to have a lower thiamine requirement than other salmonids in the lake. Lake Ontario American eel Anguilla rostrata foraging on alewife have approximately one third the muscle thiamine compared to eels not feeding on alewife, suggesting that eels may be suffering from thiamine deficiency. Secondary effects of low thiamine exist in Great Lakes salmonines and should not be ignored. Thiaminase activity in dreissenid mussels is extremely high but a connection to TDC has not been made. Thiaminase in net plankton was found more consistently in lakes Michigan and Ontario than other lakes

  3. Disruption of the lower food web in Lake Ontario: Did it affect alewife growth or condition?

    USGS Publications Warehouse

    O'Gorman, R.; Prindle, S.E.; Lantry, J.R.; Lantry, B.F.

    2008-01-01

    From the early 1980s to the late 1990s, a succession of non-native invertebrates colonized Lake Ontario and the suite of consequences caused by their colonization became known as "food web disruption". For example, the native burrowing amphipod Diporeia spp., a key link in the profundal food web, declined to near absence, exotic predaceous cladocerans with long spines proliferated, altering the zooplankton community, and depth distributions of fishes shifted. These changes had the potential to affect growth and condition of planktivorous alewife Alosa pseudoharengus, the most abundant fish in the lake. To determine if food web disruption affected alewife, we used change-point analysis to examine alewife growth and adult alewife condition during 1976-2006 and analysis-of-variance to determine if values between change points differed significantly. There were no change points in growth during the first year of life. Of three change points in growth during the second year of life, one coincided with the shift in springtime distribution of alewife to deeper water but it was not associated with a significant change in growth. After the second year of life, no change points in growth were evident, although growth in the third year of life spiked in those years when Bythotrephes, the largest of the exotic cladocerans, was abundant suggesting that it was a profitable prey item for age-2 fish. We detected two change points in condition of adult alewife in fall, but the first occurred in 1981, well before disruption began. A second change point occurred in 2003, well after disruption began. After the springtime distribution of alewife shifted deeper during 1992-1994, growth in the first two years of life became more variable, and growth in years of life two and older became correlated (P < 0.05). In conclusion, food web disruption had no negative affect on growth and condition of alewife in Lake Ontario although it appears to have resulted in growth in the first two years of

  4. Numerical Field Model Simulation of Full Scale Fire Tests in a Closed and an Open Compartment

    DTIC Science & Technology

    1992-12-01

    30,30,25) COMM4ON/BL38/TCOUP(30) ,CXl(30) ,CY(30) ,CZ(30) ,NTH(30,3) ,NTHCO COMMON/BL39/ALEW, CONSRA, QSIN, QSWER, QSWAL, QSAIR , QSFAN, QSHOL COMMON/BL4 0...GC, RAIR, NT COMMON/BL39/.ALEW, CONSRA, QSIN, QSWER, QSWAL, QSAIR , QSFAN, QSHOL C ~~SPECIFY THE INITIAL DATA DATA UO, PRT, RHOO , CPO, VISO , NTMAXO...30,30,25),COND(30,30,25),RESORM(40), & CPM(30,30,25),NHSZ(3,2),NOD(30,30,25) COMMON/BL39/ALEW, CONSRA, QSIN, QSWER, QSWAL, QSAIR , QSFAN, QSHOL COMMON

  5. Great Lakes prey fish populations: a cross-basin overview of status and trends based on bottom trawl surveys, 1978-2013

    USGS Publications Warehouse

    Gorman, Owen T.; Weidel, Brian C.

    2014-01-01

    The assessment of Great Lakes prey fish stocks have been conducted annually with bottom trawls since the 1970s by the Great Lakes Science Center, sometimes assisted by partner agencies. These stock assessments provide data on the status and trends of prey fish that are consumed by important commercial and recreational fishes. Although all these annual surveys are conducted using bottom trawls, they differ among the lakes in the proportion of the lake covered, seasonal timing, trawl gear used, and the manner in which the trawl is towed (across or along bottom contours). Because each assessment is unique, population indices were standardized to the highest value for a time series within each lake for the following prey species: Cisco (Coregonus artedi), Bloater (C. hoyi), Rainbow Smelt (Osmerus mordax), Alewife (Alosa pseudoharengus), and Round Goby (Neogobius melanostomus). In this report, standardized indices are presented in graphical form along with synopses to provide a short, informal cross-basin summary of the status and trends of principal prey fishes. There was basin-wide agreement in the trends of age-1 and older biomass for all prey species, with the highest concordance occurring for coregonids and Rainbow Smelt, and weaker concordance for Alewife. For coregonids, the highest biomass occurred from the mid-1980s to the mid-1990s. Rainbow Smelt biomass declined slowly and erratically during the last quarter century. Alewife biomass was generally higher from the early 1980s through 1990s across the Great Lakes, but since the early 1990s, trends have been divergent across the lakes, though there has been a downward trend in all lakes since 2005. Recently, Lake Huron has shown resurgence in biomass of Bloater, achieving 75% of its maximum record in 2012 due to recruitment of a succession of strong and moderate year classes that appeared in 2005-2011. Also, strong recruitment of the 2010 year class of Alewife has led to a sharp increase in biomass of Alewife in

  6. Experimental evidence that phenotypic divergence in predators drives community divergence in prey.

    PubMed

    Palkovacs, Eric P; Post, David M

    2009-02-01

    Studies of adaptive divergence have traditionally focused on the ecological causes of trait diversification, while the ecological consequences of phenotypic divergence remain relatively unexplored. Divergence in predator foraging traits, in particular, has the potential to impact the structure and dynamics of ecological communities. To examine the effects of predator trait divergence on prey communities, we exposed zooplankton communities in lake mesocosms to predation from either anadromous or landlocked (freshwater resident) alewives, which have undergone recent and rapid phenotypic differentiation in foraging traits (gape width, gill raker spacing, and prey size-selectivity). Anadromous alewives, which exploit large prey items, significantly reduced the mean body size, total biomass, species richness, and diversity of crustacean zooplankton relative to landlocked alewives, which exploit smaller prey. The zooplankton responses observed in this experiment are consistent with patterns observed in lakes. This study provides direct evidence that phenotypic divergence in predators, even in its early stages, can play a critical role in determining prey community structure.

  7. A highly permeable species boundary between two anadromous fishes.

    PubMed

    Coscia, I; Rountree, V; King, J J; Roche, W K; Mariani, S

    2010-10-01

    Meristic identification, mitochondrial DNA and a suite of microsatellite markers were employed to estimate the incidence of hybridization in wild populations of anadromous Allis shad Alosa alosa and twaite shad Alosa fallax in southern Irish riverine and estuarine waters. It was shown that 16% of the fishes examined were misclassified using meristic count of gill rakers. Next, a significant proportion of fishes that were robustly assigned to a species using nuclear markers were shown to possess the mtDNA of the other. The genomes of A. alosa and A. fallax in Ireland are extensively introgressed, which suggests a complex history of hybridization between these species, which can only partially be explained by recent man-made habitat changes.

  8. 50 CFR 600.1400 - Definitions.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ...: Alosa alabamae Striped bass: Morone saxatilis Rainbow smelt: Osmerus mordax Atlantic salmon: Salmo salar Chinook, or king, salmon: Oncorhynchus tshawytscha Coho, or silver, salmon: Oncorhynchus kisutch Pink salmon: Oncorhynchus gorbuscha Sockeye salmon: Oncorhynchus nerka Chum salmon: Oncorhynchus...

  9. 50 CFR 600.1400 - Definitions.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ...: Alosa alabamae Striped bass: Morone saxatilis Rainbow smelt: Osmerus mordax Atlantic salmon: Salmo salar Chinook, or king, salmon: Oncorhynchus tshawytscha Coho, or silver, salmon: Oncorhynchus kisutch Pink salmon: Oncorhynchus gorbuscha Sockeye salmon: Oncorhynchus nerka Chum salmon: Oncorhynchus...

  10. 50 CFR 600.1400 - Definitions.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ...: Alosa alabamae Striped bass: Morone saxatilis Rainbow smelt: Osmerus mordax Atlantic salmon: Salmo salar Chinook, or king, salmon: Oncorhynchus tshawytscha Coho, or silver, salmon: Oncorhynchus kisutch Pink salmon: Oncorhynchus gorbuscha Sockeye salmon: Oncorhynchus nerka Chum salmon: Oncorhynchus...

  11. Environmental Guide to the Virginia Capes Operating Area

    DTIC Science & Technology

    1973-03-01

    Sharks occur throughout the area with large concentrations in Shelf Water and near the shelf break. An exception is the hammerhead shark which...invertebrates occupy the waters over the shelf. Among fishes found here are croakers, sea robins, sea bass, sharks , rays, bluefish, alewives, and

  12. The Environmental Effects of Underwater Explosions with Methods to Mitigate Impacts

    DTIC Science & Technology

    1997-08-01

    INTRODUCTION  INJURY AND MORTALITY OF MARINE MAMMALS EXPOSED TO UNDERWATER EXPLOSIONS  BEHAVIORAL EFFECTS OF UNDERWATER BLASTING ON MARINE MAMMALS...P Geoghegan, J. J. Reichle, J. K. Menezes, and J. K. Watson . 1992. Alewives avoid high-frequency sound. North American Journal of Fisheries...F. W. 1954. Experiments on the effects of seismographic exploration on oysters. Proceedings National Shellfish Association 1953:93-104. Skinner , F

  13. Tambora and the mackerel year: Phenology and fisheries during an extreme climate event.

    PubMed

    Alexander, Karen E; Leavenworth, William B; Willis, Theodore V; Hall, Carolyn; Mattocks, Steven; Bittner, Steven M; Klein, Emily; Staudinger, Michelle; Bryan, Alexander; Rosset, Julianne; Carr, Benjamin H; Jordaan, Adrian

    2017-01-01

    Global warming has increased the frequency of extreme climate events, yet responses of biological and human communities are poorly understood, particularly for aquatic ecosystems and fisheries. Retrospective analysis of known outcomes may provide insights into the nature of adaptations and trajectory of subsequent conditions. We consider the 1815 eruption of the Indonesian volcano Tambora and its impact on Gulf of Maine (GoM) coastal and riparian fisheries in 1816. Applying complex adaptive systems theory with historical methods, we analyzed fish export data and contemporary climate records to disclose human and piscine responses to Tambora's extreme weather at different spatial and temporal scales while also considering sociopolitical influences. Results identified a tipping point in GoM fisheries induced by concatenating social and biological responses to extreme weather. Abnormal daily temperatures selectively affected targeted fish species-alewives, shad, herring, and mackerel-according to their migration and spawning phenologies and temperature tolerances. First to arrive, alewives suffered the worst. Crop failure and incipient famine intensified fishing pressure, especially in heavily settled regions where dams already compromised watersheds. Insufficient alewife runs led fishers to target mackerel, the next species appearing in abundance along the coast; thus, 1816 became the "mackerel year." Critically, the shift from riparian to marine fisheries persisted and expanded after temperatures moderated and alewives recovered. We conclude that contingent human adaptations to extraordinary weather permanently altered this complex system. Understanding how adaptive responses to extreme events can trigger unintended consequences may advance long-term planning for resilience in an uncertain future.

  14. Tambora and the mackerel year: Phenology and fisheries during an extreme climate event

    PubMed Central

    Alexander, Karen E.; Leavenworth, William B.; Willis, Theodore V.; Hall, Carolyn; Mattocks, Steven; Bittner, Steven M.; Klein, Emily; Staudinger, Michelle; Bryan, Alexander; Rosset, Julianne; Carr, Benjamin H.; Jordaan, Adrian

    2017-01-01

    Global warming has increased the frequency of extreme climate events, yet responses of biological and human communities are poorly understood, particularly for aquatic ecosystems and fisheries. Retrospective analysis of known outcomes may provide insights into the nature of adaptations and trajectory of subsequent conditions. We consider the 1815 eruption of the Indonesian volcano Tambora and its impact on Gulf of Maine (GoM) coastal and riparian fisheries in 1816. Applying complex adaptive systems theory with historical methods, we analyzed fish export data and contemporary climate records to disclose human and piscine responses to Tambora’s extreme weather at different spatial and temporal scales while also considering sociopolitical influences. Results identified a tipping point in GoM fisheries induced by concatenating social and biological responses to extreme weather. Abnormal daily temperatures selectively affected targeted fish species—alewives, shad, herring, and mackerel—according to their migration and spawning phenologies and temperature tolerances. First to arrive, alewives suffered the worst. Crop failure and incipient famine intensified fishing pressure, especially in heavily settled regions where dams already compromised watersheds. Insufficient alewife runs led fishers to target mackerel, the next species appearing in abundance along the coast; thus, 1816 became the “mackerel year.” Critically, the shift from riparian to marine fisheries persisted and expanded after temperatures moderated and alewives recovered. We conclude that contingent human adaptations to extraordinary weather permanently altered this complex system. Understanding how adaptive responses to extreme events can trigger unintended consequences may advance long-term planning for resilience in an uncertain future. PMID:28116356

  15. Lake Michigan faces exotic species, dune sand mining, other challenges

    NASA Astrophysics Data System (ADS)

    Showstack, Randy

    As Steve Pothoven scooped out his bottom trawl catch on the deck of a U.S. government research vessel in June, he expected the regular monitoring exercise to land alewives and a mound of zebra mussels. These two now-ubiquitous exotic aquatic species are among more than 130 that have entered the Great Lakes ecosystem over the past century. They have invaded by various means: hiding in ballast water, navigating through connecting channels such as the Welland Canal that was completed in 1829 as a route around Niagara Falls, or introduced on purpose.

  16. Habitat Suitability Index Models: Alewife and blueback herring

    USGS Publications Warehouse

    Pardue, Garland B.

    1983-01-01

    Alewives and blueback herring are anadromous clupeids found along the Atlantic coast in marine, estuarine, and riverine habitats, depending upon life stage. Both are important commercial species, used fresh or salted for human consumption, and used as crab bait, fish meal (particularly in animal food manufacturing), and fish oil. Alewife and blueback herring are marketed collectively as 'river herring,' a term that will be used for both species in this report. River herring play important ecological roles. In marine, estuarine, and riverine food webs, they occupy a level between zooplankton, their principal food, and piscivores.

  17. A species-to-be? The genetic status and colonization history of the critically endangered Killarney shad.

    PubMed

    Coscia, Ilaria; McDevitt, Allan D; King, James J; Roche, William K; McLoughlin, Carol; Mariani, Stefano

    2013-12-01

    Typically anadromous, the twaite shad (Alosa fallax) can become landlocked and adapt to a fully freshwater life. The only landlocked shad population in Northwestern Europe is found in a lake in Ireland, Lough Leane. The Killarney shad, Alosa killarnensis (or Alosa fallax killarnensis, as it is mostly referred to) displays a level of morphological divergence that indicates a long-term isolation in the lake. Microsatellites and mtDNA control region sequences were used within a coalescent framework (BEAST and Approximate Bayesian Computation (ABC)) to investigate its colonization history and to clarify its taxonomic status. Results indicate that the lake was likely colonized in two independent events, the first coinciding with the retreat of the ice sheet from the area after the Last Glacial Maximum and the second after the Younger Dryas. Microsatellite data has shown that these two landlocked lineages have completely admixed within the lake, and have started diverging significantly from their closest ancestor, the twaite shad. We argue that our molecular results (together with the life-history and physiological divergence between Killarney and twaite shad) are conspicuous enough to view the landlocked population as a new species, and one whose future existence would certainly not be insured by its sister taxon.

  18. Using time-varying asymptotic length and body condition of top piscivores to indicate ecosystem regime shift in the main basin of Lake Huron: a Bayesian hierarchical modeling approach

    USGS Publications Warehouse

    He, Ji X.; Bence, James R.; Roseman, Edward F.; Fielder, David G.; Ebener, Mark P.

    2015-01-01

    We evaluated the ecosystem regime shift in the main basin of Lake Huron that was indicated by the 2003 collapse of alewives, and dramatic declines in Chinook salmon abundance thereafter. We found that the period of 1995-2002 should be considered as the early phase of the final regime shift. We developed two Bayesian hierarchical models to describe time-varying growth based on the von Bertalanffy growth function and the length-mass relationship. We used asymptotic length as an index of growth potential, and predicted body mass at a given length as an index of body condition. Modeling fits to length and body mass at age of lake trout, Chinook salmon, and walleye were excellent. Based on posterior distributions, we evaluated the shifts in among-year geometric means of the growth potential and body condition. For a given top piscivore, one of the two indices responded to the regime shift much earlier than the 2003 collapse of alewives, the other corresponded to the 2003 changes, and which index provided the early signal differed among the three top piscivores.

  19. Numerical Field Model Simulation of Fire and Heat Transfer in a Rectangular Compartment

    DTIC Science & Technology

    1992-09-01

    QSAIR ,QSFAN COMMON/BL4O/ VFHSW(5 ,25, 15) ,VFHSE(5 ,25,15),VFHSS(5, 15 ,25), & VFHSN(5,15,25),VFHSB(5,25,25) ,VFHSF(5,25,25) COMMON/BL41/VFHSBW...QSIN,QSWER,QSWAL, QSAIR ,QSFAN C *** SPECIFY THE INITIAL DATA DATA UO, PRT, RHOO , CPO, VISO , NTMAXO/ & 1.0, 1.0, 0.0714, 0.24, 1.56D-4, 0/ DATA CNT...COMMON/BL37/VIS(25.,25,15),COND(25,25,15),RESORM(40), & CPM(25,25,1S) ,NHSZ(3,2) ,NOD(25,25.,15) COMMON/BL39/ALEW,CONSRA,QSIN,QSWER,QSWAL, QSAIR ,QSFAN

  20. The Lake Ontario zooplankton community before (1987-1991) and after (2001-2005) invasion-induced ecosystem change

    USGS Publications Warehouse

    Stewart, T.J.; Johannsson, O.E.; Holeck, K.; Sprules, W.G.; O'Gorman, R.

    2010-01-01

    We assessed changes in Lake Ontario zooplankton biomass, production, and community composition before (1987–1991) and after (2001–2005) invasion-induced ecosystem changes. The ecosystem changes were associated with establishment of invasive dreissenid mussels and invasive predatory cladocerans (Bythotrephes and Cercopagis). Whole-lake total epilimnetic plus metalimnetic zooplankton production declined by approximately half from 42.45 (g dry wt∙m−2∙ year−1) during 1987–1991 to 21.91 (g dry wt∙m−2∙ year−1) in 2003 and averaged 21.01 (g dry wt∙m−2∙ year−1) during 2001–2005. Analysis of two independent data sets indicates that the mean biomass and biomass proportion of cyclopoid copepods declined while the same measures increased for the invasive predatory cladocerans. Changes in means and proportions of all other zooplankton groups were not consistent between the data sets. Cyclopoid copepod biomass and production declined by factors ranging from 3.6 to 5.7. Invasive predatory cladoceran biomass averaged from 5.0% to 8.0% of the total zooplankton biomass. The zooplankton community was otherwise resilient to the invasion-induced disruption as zooplankton species richness and diversity were unaffected. Zooplankton production was likely reduced by declines in primary productivity but may have declined further due to increased predation by alewives and invasive predatory cladocerans. Shifts in zooplankton community structure were consistent with increased predation pressure on cyclopoid copepods by alewives and invasive predatory cladocerans. Predicted declines in the proportion of small cladocerans were not evident. This study represents the first direct comparison of changes in Lake Ontario zooplankton production before and after the invasion-induced disruption and will be important to food web-scale investigations of invasion effects.

  1. Contribution of anadromous fish to the diet of European catfish in a large river system

    NASA Astrophysics Data System (ADS)

    Syväranta, Jari; Cucherousset, Julien; Kopp, Dorothée; Martino, Aurélia; Céréghino, Régis; Santoul, Frédéric

    2009-05-01

    Many anadromous fish species, when migrating from the sea to spawn in fresh waters, can potentially be a valuable prey for larger predatory fish, thereby efficiently linking these two ecosystems. Here, we assess the contribution of anadromous fish to the diet of European catfish ( Silurus glanis) in a large river system (Garonne, southwestern France) using stable isotope analysis and allis shad ( Alosa alosa) as an example of anadromous fish. Allis shad caught in the Garonne had a very distinct marine δ13C value, over 8‰ higher after lipid extraction compared to the mean δ13C value of all other potential freshwater prey fish. The δ13C values of European catfish varied considerably between these two extremes and some individuals were clearly specializing on freshwater prey, whereas others specialized on anadromous fish. The mean contribution of anadromous fish to the entire European catfish population was estimated to be between 53% and 65%, depending on the fractionation factor used for δ13C.

  2. Thiaminase activity and life history investigations in American Shad in the Columbia river

    USGS Publications Warehouse

    Wetzel, Lisa A.; Parsley, Michael J; van der Leeuw, Bjorn K.; Larsen, Kimberly A.

    2011-01-01

    American shad Alosa sapidissima fry were successfully transplanted from the Atlantic to the Pacific coast in 1871 and have subsequently proliferated. The Columbia River population is in the millions, yet few investigations have been conducted to better understand their life history, population dynamics, or potential impacts on other species. In 2007 and 2008 we captured American shad from the Columbia River to assess levels of thiaminase activity and to characterize some aspects of American shad life history. Thiaminase levels in age-0 and adult fish were high and ranged from 4,113-20,874 pmol/g/min. Ages of spawning American shad ranged from 3-7 years and iteroparity was approximately 33-36% in the spawning population. Males were typically younger and smaller and had a higher degree of iteroparity than females

  3. Development of a bioenergetics model for age-0 American Shad

    USGS Publications Warehouse

    Sauter, Sally T.

    2011-01-01

    Bioenergetics modeling can be used as a tool to investigate the impact of non-native age-0 American shad (Alosa sapidissima) on reservoir and estuary food webs. The model can increase our understanding of how these fish influence lower trophic levels as well as predatory fish populations that feed on juvenile salmonids. Bioenergetics modeling can be used to investigate ecological processes, evaluate alternative research hypotheses, provide decision support, and quantitative prediction. Bioenergetics modeling has proven to be extremely useful in fisheries research (Ney et al. 1993,Chips and Wahl 2008, Petersen et al. 2008). If growth and diet parameters are known, the bioenergetics model can be used to quantify the relative amount of zooplankton or insects consumed by age-0 American shad. When linked with spatial and temporal information on fish abundance, model output can guide inferential hypothesis development to demonstrate where the greatest impacts of age-0 American shad might occur.

  4. The Combined Use of Correlative and Mechanistic Species Distribution Models Benefits Low Conservation Status Species

    PubMed Central

    Rougier, Thibaud; Lassalle, Géraldine; Drouineau, Hilaire; Dumoulin, Nicolas; Faure, Thierry; Deffuant, Guillaume; Rochard, Eric; Lambert, Patrick

    2015-01-01

    Species can respond to climate change by tracking appropriate environmental conditions in space, resulting in a range shift. Species Distribution Models (SDMs) can help forecast such range shift responses. For few species, both correlative and mechanistic SDMs were built, but allis shad (Alosa alosa), an endangered anadromous fish species, is one of them. The main purpose of this study was to provide a framework for joint analyses of correlative and mechanistic SDMs projections in order to strengthen conservation measures for species of conservation concern. Guidelines for joint representation and subsequent interpretation of models outputs were defined and applied. The present joint analysis was based on the novel mechanistic model GR3D (Global Repositioning Dynamics of Diadromous fish Distribution) which was parameterized on allis shad and then used to predict its future distribution along the European Atlantic coast under different climate change scenarios (RCP 4.5 and RCP 8.5). We then used a correlative SDM for this species to forecast its distribution across the same geographic area and under the same climate change scenarios. First, projections from correlative and mechanistic models provided congruent trends in probability of habitat suitability and population dynamics. This agreement was preferentially interpreted as referring to the species vulnerability to climate change. Climate change could not be accordingly listed as a major threat for allis shad. The congruence in predicted range limits between SDMs projections was the next point of interest. The difference, when noticed, required to deepen our understanding of the niche modelled by each approach. In this respect, the relative position of the northern range limit between the two methods strongly suggested here that a key biological process related to intraspecific variability was potentially lacking in the mechanistic SDM. Based on our knowledge, we hypothesized that local adaptations to cold

  5. Food of young-of-the-year walleyes in Lake Erie

    USGS Publications Warehouse

    Wolfert, David R.

    1966-01-01

    Stomach contents were examined for 794 young-of-the-year (0-group) walleyes (Stizostedion vitreum vitreum) captured by trawls at 17 locations in western Lake Erie in June-November 1962. Food organisms were found in 92.5 percent of the stomachs. Food varied with geographic location and season of capture, but within areas and seasons, selection for certain species and sizes of prey was strong. Walleyes from the extreme western end of Lake Erie fed primarily on gizzard shad and alewives during the summer and shifted to emerald shiners during the fall. The stomach contents of walleyes from the Island region changed from mainly yellow perch during the summer to emerald shiners by the end of the year. Walleyes collected east of the Islands had consumed only smelt and yellow perch. The numbers of forage species caught with walleyes in trawls showed little correlation with the representation of these species in walleye stomachs. Walleyes fed on the smallest individuals of each species regardless of species preferences.

  6. Effects of alewife predation on zooplankton populations in Lake Michigan

    USGS Publications Warehouse

    Wells, LaRue

    1970-01-01

    The zooplankton populations in southeastern Lake Michigan underwent striking, size-related changes between 1954 and 1966. Forms that decline sharply were the largest cladocerans (Leptodora kindtii, Daphnia galeata, and D. retrocurva), the largest calanoid copepods (Limnocalanus macrurus, Epischura lacustris, and Diaptomus sicilis), and the largest cyclopoid copepod (Mesocyclops edax). Two of these, D. galeata and M. edax (both abundant in 1954), became extremely rare. Certain medium-sized or small species increased in numbers: Daphnia longiremis, Holopedium gibberum, Polyphemus pediculus, Bosmina longirostris, Bosmina coregoni, Ceriodaphnia sp., Cyclops bicuspidatus, Cyclops vernalis, and Diaptomus ashlandi. Evidence is strong that the changes were due to selective predation by alewives. The alewife was uncommon in southeastern Lake Michigan in 1954 but had increased to enormous proportions by 1966; there was a massive dieoff in spring 1967, and abundance remained relatively low in 1968. The composition of zooplankton populations in 1968 generally had shifted back toward that of 1954, although D. galeata and M. edax remained rare. The average size, and size at onset of maturity, of D. retrocurva decreased noticeably between 1954 and 1966 but increased between 1966 and 1968.

  7. The present status of the United States commercial fisheries of the Great Lakes

    USGS Publications Warehouse

    Van Oosten, John

    1949-01-01

    This review of the trends in production on the Great Lakes suggests that great biological changes have taken place. The general abundance of the choicer varieties, and of some of the less choice fishes, has been lowered considerably; and the prospects are that this level will fall still farther. In addition, the niches occupied by these finer species in the lakes have not been filled by coarser forms. Much of the reduced abundance in modern fishery must be attributed to overfishing or unwise fishing (cisco, whitefish, lake trout, chubs). Part of it we believe was caused by an infectious disease as was true for the smelt; part of it by the parasitic predator, the sea lamprey. Perhaps increased competition for space or food such as might have been brought about by the smelt in Lakes Huron and Michigan or the alewives in Lake Ontario may have played a role. Pollution, too, may have taken its toll. Often we have no better explanation to offer than to state that some unknown change in the environment was responsible.

  8. Energy budget for yearling lake trout, Salvelinus namaycush

    USGS Publications Warehouse

    Rottiers, Donald V.

    1993-01-01

    Components of the energy budget of yearling lake trout (Salvelinus namaycush) were derived from data gathered in laboratory growth and metabolism studies; values for energy lost as waste were estimated with previously published equations. Because the total caloric value of food consumed by experimental lake trout was significantly different during the two years in which the studies were done, separate annual energy budgets were formulated. The gross conversion efficiency in yearling lake trout fed ad libitum rations of alewives at 10A?C was 26.6% to 41%. The distribution of energy with temperature was similar for each component of the energy budget. Highest conversion efficiencies were observed in fish fed less than ad libitum rations; fish fed an amount of food equivalent to about 4% of their body weight at 10A?C had a conversion efficiency of 33% to 45.1%. Physiologically useful energy was 76.1-80.1% of the total energy consumed. Estimated growth for age-I and -II lake fish was near that observed for laboratory fish held at lake temperatures and fed reduced rations.

  9. Seasonal zooplankton dynamics in Lake Michigan: disentangling impacts of resource limitation, ecosystem engineering, and predation during a critical ecosystem transition

    USGS Publications Warehouse

    Vanderploeg, Henry A.; Pothoven, Steven A.; Fahnenstiel, Gary L.; Cavaletto, Joann F.; Liebig, James R.; Stow, Craig Stow; Nalepa, Thomas F.; Madenjian, Charles P.; Bunnell, David B.

    2012-01-01

    We examined seasonal dynamics of zooplankton at an offshore station in Lake Michigan from 1994 to 2003 and 2007 to 2008. This period saw variable weather, declines in planktivorous fish abundance, the introduction and expansion of dreissenid mussels, and a slow decline in total phosphorus concentrations. After the major expansion of mussels into deep water (2007–2008), chlorophyll in spring declined sharply, Secchi depth increased markedly in all seasons, and planktivorous fish biomass declined to record-low levels. Overlaying these dramatic ecosystem-level changes, the zooplankton community exhibited complex seasonal dynamics between 1994–2003 and 2007–2008. Phenology of the zooplankton maximum was affected by onset of thermal stratification, but there was no other discernable effect due to temperature. Interannual variability in zooplankton biomass during 1994 and 2003 was strongly driven by planktivorous fish abundance, particularly age-0 and age-1 alewives. In 2007–2008, there were large decreases in Diacyclops thomasi and Daphnia mendotae possibly caused by food limitation as well as increased predation and indirect negative effects from increases in Bythotrephes longimanus abundance and in foraging efficiency associated with increased light penetration. The Bythotrephes increase was likely driven in part by decreased predation from yearling and older alewife. While there was a major decrease in epilimnetic–metalimnetic herbivorous cladocerans in 2007–2008, there was an increase in large omnivorous and predacious calanoid copepods, especially those in the hypolimnion. Thus, changes to the zooplankton community are the result of cascading, synergistic interactions, including a shift from vertebrate to invertebrate planktivory and mussel ecosystem impacts on light climate and chlorophyll.

  10. Limitations to lake trout (Salvelinus namaycush) rehabilitation in the Great Lakes imposed by biotic interactions occurring at early life stages

    USGS Publications Warehouse

    Jones, Michael L.; Eck, Gary W.; Evans, David O.; Fabrizio, Mary C.; Hoff, Michael H.; Hudson, Patrick L.; Janssen, John; Jude, David; O'Gorman, Robert; Savino, Jacqueline F.

    1995-01-01

    We examine evidence that biotic factors, particularly predation, may be limiting early survival of wild lake trout (Salvelinus namaycush) juveniles in many areas of the Great Lakes. The Great Lakes contain numerous potential predators of lake trout eggs and fry, some of which are recent invaders, and most of which were probably absent when lake trout most recently re-invaded the Great Lakes after the last ice age. Simple quantitative models of predation suggest that plausible assumptions about prey densities, predator feeding rates, and duration of exposure of predator to prey can lead to very high estimates of predation mortality, in some instances approaching 100%. Indirect evidence from inter-Great Lake comparisons and inland lake examples also suggest that biotic factors may impede successful lake trout colonization. Our synthesis of the evidence leads to recommendations for research to better define field feeding rates of lake trout egg and fry predators and comparative studies of densities of potential egg and fry predators on lake trout spawning reefs. Management options should be designed to provide useful information as well as achieve short-term goals. From a management standpoint we recommend that: newly constructed lake trout reefs should be placed well away from concentrations of potential predators; offshore spawning reefs should be stocked; salmonine stocking, nutrient abatement, and commercial harvest of alewives should all be considered as options to enhance survival of young lake trout; hatchery lake trout should not be stocked at sites where wild lake trout are showing signs of recovery; and exotic species expansions or introductions must be curtailed to maintain or improve on our recent successes in lake trout rehabilitation.

  11. Revisiting the classics: considering nonconsumptive effects in textbook examples of predator-prey interactions.

    PubMed

    Peckarsky, Barbara L; Abrams, Peter A; Bolnick, Daniel I; Dill, Lawrence M; Grabowski, Jonathan H; Luttbeg, Barney; Orrock, John L; Peacor, Scott D; Preisser, Evan L; Schmitz, Oswald J; Trussell, Geoffrey C

    2008-09-01

    Predator effects on prey dynamics are conventionally studied by measuring changes in prey abundance attributed to consumption by predators. We revisit four classic examples of predator-prey systems often cited in textbooks and incorporate subsequent studies of nonconsumptive effects of predators (NCE), defined as changes in prey traits (e.g., behavior, growth, development) measured on an ecological time scale. Our review revealed that NCE were integral to explaining lynx-hare population dynamics in boreal forests, cascading effects of top predators in Wisconsin lakes, and cascading effects of killer whales and sea otters on kelp forests in nearshore marine habitats. The relative roles of consumption and NCE of wolves on moose and consequent indirect effects on plant communities of Isle Royale depended on climate oscillations. Nonconsumptive effects have not been explicitly tested to explain the link between planktonic alewives and the size structure of the zooplankton, nor have they been invoked to attribute keystone predator status in intertidal communities or elsewhere. We argue that both consumption and intimidation contribute to the total effects of keystone predators, and that characteristics of keystone consumers may differ from those of predators having predominantly NCE. Nonconsumptive effects are often considered as an afterthought to explain observations inconsistent with consumption-based theory. Consequently, NCE with the same sign as consumptive effects may be overlooked, even though they can affect the magnitude, rate, or scale of a prey response to predation and can have important management or conservation implications. Nonconsumptive effects may underlie other classic paradigms in ecology, such as delayed density dependence and predator-mediated prey coexistence. Revisiting classic studies enriches our understanding of predator-prey dynamics and provides compelling rationale for ramping up efforts to consider how NCE affect traditional predator

  12. Changes in seasonal nearshore zooplankton abundance patterns in Lake Ontario following establishment of the exotic predator Cercopagis pengoi

    USGS Publications Warehouse

    Warner, David M.; Rudstam, Lars G.; Benoit, Hugues; Mills, Edward L.; Johannsson, Ora E.

    2006-01-01

    Cercopagis pengoi, a zooplanktivore first discovered in Lake Ontario in 1998, may reduce availability of prey for planktivorous fish. Cercoapgis pengoi is most abundant in late summer and fall. Therefore, we hypothesized that abundance of small zooplankton (bosminids and cyclopoids) species would decrease at that time. To determine if the establishment of C. pengoi was followed by changes in the zooplankton community, seasonal patterns in nearshore zooplankton collected from May to October 1995–2000 were examined. Early summer density of small zooplankton was similar in all years while late summer and fall densities were significantly lower in 1998–2000 than in 1995–1997. The declines of small zooplankton coincided seasonally with the peak in C. pengoidensity. Other possible causes for the observed changes in small zooplankton are less likely. High levels of fish predation should have resulted in smaller zooplankton in 1998–2000 than in 1995–1997 and larger declines in Daphnia than other groups. This was not observed. There was no significant decline in chlorophyll-a concentrations or changes in temperature between 1995–1997 and 1998–2000. Therefore, the declines in density of small zooplankton were most likely the result of C. pengoi predation. The effect of C. pengoi establishment on alewives is increased competition for zooplankton prey but C. pengoi has replaced a portion of the zooplankton biomass and adult alewife diet formerly dominated by Diacyclops thomasi and Bosmina longirostris.

  13. The growth-temperature relation and preferred temperatures of juvenile lake herring

    USGS Publications Warehouse

    Edsall, T.A.; Desorcie, T.J.

    2002-01-01

    Lake herring, Coregonus artedi, were once extremely abundant in the Great Lakes where they functioned as a major trophic integrator, directly linking the planktonic crustacean resource to lake trout. Salvelinus namaycush. Lake herring populations in the Great Lakes collapsed during the middle third of the 20th century due to overfishing, degradation of critical habitat in major production areas, and interaction with exotic species. Fishery and habitat impediments to the recovery of lake herring have been removed, and it may now be possible to reestablish the species in its former habitats in the Great Lakes if adverse interactions with exotic species can be controlled within acceptable limits. To determine the potential for thermal niche overlap and adverse interaction with exotic fishes, juvenile (age-0) lake herring were held in the laboratory at 5, 10, 15, 18, and 21 C, and fed ad libitum for 54 days. The optimum temperature for growth in weight was about 14.5 C, indicating the fundamental thermal niche was 12.5-16.5 C. Fish used in the growth study were also tested in a vertical thermal gradient tank to measure their final preferendum. The final preferendum, 16.5 C, was in close agreement with the optimum temperature for growth and within the fundamental thermal niche. Both the optimum temperature for growth and the final preferendum have been used as measures of thermal niche, but this is the first time both measures were made on the same group of fish. Published information on the fundamental thermal niche, preferred temperatures, thermal habitat use, and feeding habits of alewives, rainbow smelt, and ruffe, indicates they will co-occur in spring, or summer with age-0 lake herring and that collectively they pose a predation threat to small, age-0 lake herring.

  14. Starvation resistance in lake trout fry

    USGS Publications Warehouse

    Edsall, Thomas A.; Manny, Bruce A.; Kennedy, Gregory W.

    2003-01-01

    Newly hatched fry were acclimated to 7 or 12A?C and either fed daily (controls) or denied food for varying lengths of time and then fed daily until the end of the study (day 91 at 7A?C and day 43 at 12A?C). Growth was reduced by delays in the onset of feeding of 27 or more days at 7A?C and 7 or more days at 12A?C. Mortality of fry unfed for more than 34 days at 7A?C, or more than 21 days at 12A?C, was higher than among controls. Daily mortality increased with the length of the food deprivation period and did not cease immediately when food was made available, but reached zero by the end of the study. Mortality among unfed fry reached 50% in about 59 days at 7A?C and 32 days at 12A?C. Study results permitted calculation of the 'point-of-no-return' (PNR) mortality, which included the mortality that occurred during the period of food deprivation, and also the delayed component of mortality that was directly attributable to starvation and that occurred after food was made available. The PNR for 50% mortality for food-deprived fry occurred after 52 days at 7A?C and 24 days at 12A?C. Thus, both measures of mortality indicate that lake trout fry would be highly resistant to death by starvation in the thermal habitat they would be expected to occupy in the Great Lakes. We conclude that a more likely adverse effect of reduced food availability would result from a reduction in growth rate that extends the length of time fry remain small and vulnerable to predation by adult alewives and other non-native fishes with which they associate.

  15. Pacific salmonines in the Great Lakes Basin

    USGS Publications Warehouse

    Claramunt, Randall M.; Madenjian, Charles P.; Clapp, David; Taylor, William W.; Lynch, Abigail J.; Leonard, Nancy J.

    2012-01-01

    Pacific salmon (genus Oncorhynchus) are a valuable resource, both within their native range in the North Pacific rim and in the Great Lakes basin. Understanding their value from a biological and economic perspective in the Great Lakes, however, requires an understanding of changes in the ecosystem and of management actions that have been taken to promote system stability, integrity, and sustainable fisheries. Pacific salmonine introductions to the Great Lakes are comprised mainly of Chinook salmon, coho salmon, and steelhead and have accounted for 421, 177, and 247 million fish, respectively, stocked during 1966-2007. Stocking of Pacific salmonines has been effective in substantially reducing exotic prey fish abundances in several of the Great Lakes (e.g., lakes Michigan, Huron, and Ontario). The goal of our evaluation was to highlight differences in management strategies and perspectives across the basin, and to evaluate policies for Pacific salmonine management in the Great Lakes. Currently, a potential conflict exists between Pacific salmonine management and native fish rehabilitation goals because of the desire to sustain recreational fisheries and to develop self-sustaining populations of stocked Pacific salmonines in the Great Lakes. We provide evidence that suggests Pacific salmonines have not only become naturalized to the food webs of the Great Lakes, but that their populations (specifically Chinook salmon) may be fluctuating in concert with specific prey (i.e., alewives) whose populations are changing relative to environmental conditions and ecosystem disturbances. Remaining questions, however, are whether or not “natural” fluctuations in predator and prey provide enough “stability” in the Great Lakes food webs, and even more importantly, would a choice by managers to attempt to reduce the severity of predator-prey oscillations be antagonistic to native fish restoration efforts. We argue that, on each of the Great Lakes, managers are pursuing

  16. The Adopt-a-Herring program as a fisheries conservation tool

    USGS Publications Warehouse

    Frank, Holly J.; Mather, Martha E.; Muth, Robert M.; Pautzke, Sarah M.; Smith, Joseph M.; Finn, John T.

    2009-01-01

    Successful conservation depends on a scientifically literate public. We developed the adopt-a-Herring program to educate nonscientists about fisheries and watershed restoration. this interactive educational and outreach project encouraged coastal residents to be involved in local watershed restoration. In the northeastern United States, river herring (Alosa spp.) are an important component of many coastal watersheds and often are the object of conservation efforts. In order to understand river herring spawning behavior and to improve the effectiveness of restoration efforts, our research tracked these fish via radiotelemetry in the Ipswich River, Massachusetts. In our adopt-a-Herring Program, participating stakeholder organizations adopted and named individual tagged river herring and followed their movements online. We also made information available to our adopters on our larger research goals, the mission and activities of other research and management agencies, examples of human actions that adversely affect watersheds, and opportunities for proactive conservation. Research results were communicated to adopters through our project web page and end-of-the-season summary presentations. Both tools cultivated a personal interest in river herring, stimulated discussion about fisheries and watershed restoration, educated participants about the goals and methods of scientists in general, and initiated critical thinking about human activities that advance or impede sustainability.

  17. Status of rainbow smelt in the U.S. waters of Lake Ontario, 2013: Section 12 of NYSDEC Lake Ontario Unit annual report 2013

    USGS Publications Warehouse

    Weidel, Brian C.; Connerton, Michael J.

    2014-01-01

    Rainbow Smelt Osmerus mordax are the second most abundant pelagic prey fish in Lake Ontario after Alewife Alosa psuedoharengus. The 2013, USGS/NYSDEC bottom trawl assessment indicated the abundance of Lake Ontario age-1 and older Rainbow Smelt decreased by 69% relative to 2012. Length frequency-based age analysis indicated that age-1 Rainbow Smelt constituted approximately 50% of the population, which is similar to recent trends where the proportion of age-1 has ranged from 95% to 42% of the population. While they constituted approximately half of the catch, the overall abundance index for age 1 was one of the lowest observed in the time series, potentially a result of cannibalism from the previous year class. Combined data from all bottom trawl assessments along the southern shore and eastern basin indicate the proportion of the fish community that is Rainbow Smelt has declined over the past 30 years. In 2013 the proportion of the pelagic fish catch (only pelagic species) that was Rainbow Smelt was the second lowest in the time series at 3.1%. Community diversity indices, based on bottom trawl catches, indicate that Lake Ontario fish community diversity, as assessed by bottom trawls, has sharply declined over the past 36 years and in 2013 the index was the lowest value in the time series. Much of this community diversity decline is driven by changes in the pelagic fish community and dominance of Alewife.

  18. A spatial capture-recapture model to estimate fish survival and location from linear continuous monitoring arrays

    USGS Publications Warehouse

    Raabe, Joshua K.; Gardner, Beth; Hightower, Joseph E.

    2013-01-01

    We developed a spatial capture–recapture model to evaluate survival and activity centres (i.e., mean locations) of tagged individuals detected along a linear array. Our spatially explicit version of the Cormack–Jolly–Seber model, analyzed using a Bayesian framework, correlates movement between periods and can incorporate environmental or other covariates. We demonstrate the model using 2010 data for anadromous American shad (Alosa sapidissima) tagged with passive integrated transponders (PIT) at a weir near the mouth of a North Carolina river and passively monitored with an upstream array of PIT antennas. The river channel constrained migrations, resulting in linear, one-dimensional encounter histories that included both weir captures and antenna detections. Individual activity centres in a given time period were a function of the individual’s previous estimated location and the river conditions (i.e., gage height). Model results indicate high within-river spawning mortality (mean weekly survival = 0.80) and more extensive movements during elevated river conditions. This model is applicable for any linear array (e.g., rivers, shorelines, and corridors), opening new opportunities to study demographic parameters, movement or migration, and habitat use.

  19. Trophic interactions and consumption rates of subyearling Chinook Salmon and nonnative juvenile American Shad in Columbia River reservoirs

    USGS Publications Warehouse

    Haskell, Craig A.; Beauchamp, David A.; Bollins, Stephen M

    2017-01-01

    We used a large lampara seine coupled with nonlethal gastric lavage to examine the diets and estimate consumption rates of subyearling Chinook Salmon Oncorhynchus tshawytscha during July and August 2013. During August we also examined the diet and consumption rates of juvenile American Shad Alosa sapidissima, a potential competitor of subyearling Chinook Salmon. Subyearling Chinook Salmon consumed Daphnia in July but switched to feeding on smaller juvenile American Shad in August. We captured no juvenile American Shad in July, but in August juvenile American Shad consumed cyclopoid and calanoid copepods. Stomach evacuation rates for subyearling Chinook Salmon were high during both sample periods (0.58 h−1 in July, 0.51 h−1 in August), and daily ration estimates were slightly higher than values reported in the literature for other subyearlings. By switching from planktivory to piscivory, subyearling Chinook Salmon gained greater growth opportunity. While past studies have shown that juvenile American Shad reduce zooplankton availability for Chinook Salmon subyearlings, our work indicates that they also become important prey after Daphnia abundance declines. The diet and consumption data here can be used in future bioenergetics modeling to estimate the growth of subyearling Chinook Salmon in lower Columbia River reservoirs.

  20. Accumulation of polychlorinated biphenyls in american shad during their migration in the Hudson River, spring 1977.

    PubMed

    Pastel, M; Bush, B; Kim, J S

    1980-06-01

    Fifty-two female American shad (Alosa sapidissima) were collected during the spring of 1977 at two sites on the lower Hudson River, 27 miles and 75 miles from the river mouth. The fish were extracted with hexane, and the extracts were analyzed by electron-capture gas chromatography (EC-GC) and by GC/mass spectrometry (MS), PCBs were quantitated by EC-GC, and the concentrations were compared by fish length and by site. Fish collected from the downstream site contained a mean PCB concentration of 2.0 +/- 1.0 microgram/g, wet weight; fish from the upstream site contained a mean PCB concentration of 6.1 +/- 2.6 microgram/g, wet weight. Aliquots of the hexane extracts were fractionated before analysis by GC/MS. The presence of PCBs was confirmed, and DDE and the alkane series from C22 through C26 were detected. American shad are saltwater fish that only enter fresh water to spawn. Because they do not feed in fresh water before spawning, they may be used as an indicator of water contamination.

  1. Nocturnal Fish Use of New Jersey Marsh Creek and Adjacent Bay Shoal Habitats

    NASA Astrophysics Data System (ADS)

    Rountree, R. A.; Able, K. W.

    1997-06-01

    Night-time sampling with gill nets in the Little Egg Harbor estuary revealed a component of the estuarine fish fauna, hitherto poorly documented, which is comprised of relatively large size classes of juvenile and adult life history stages. The fishesMustelus canis, Pomatomus saltatrix, Paralichthys dentatus, Brevoortia tyrannus, Prionotus evolansandAlosa mediocriswere the most abundant fishes captured. These observations suggest that Mid-Atlantic Bight estuaries are important nurseries for juvenile stages beyond the first year, as well as for the young of the year (YOY). Although many other studies emphasise the importance of estuaries as nurseries for YOY stages, the importance of estuaries to later juvenile life stages has been largely overlooked. This component of estuarine fish fauna has been poorly represented in previous North American studies because of probable gear avoidance, and because most studies are conducted primarily during the day. The authors hypothesise that these later juvenile stages are likely to be important estuarine faunal components in other geographic regions, as well as in the Mid-Atlantic Bight. A descriptive comparison of catches between ebb and flood tide stages, and between bay shoal and tidal marsh creek habitats, suggests that later juvenile and adult stages of several species make tidal migrations into shallow estuarine habitats, such as shoals and marsh creeks, during the night hours.

  2. Redescription of Eubothrium fragile (Rudolphi, 1802) and E. rugosum (Batsch, 1786) (Cestoda: Pseudophyllidea), parasites of fish in the Holarctic Region.

    PubMed

    Kuchta, Roman; Hanzelová, Vladimíra; Shinn, Andy P; Poddubnaya, Larisa G; Scholz, Tomás

    2005-09-01

    Two fish cestodes, the little-known Eubothrium fragile (Rudolphi, 1802) and E. rugosum (Batsch, 1786), the type species of the genus Eubothrium Nybelin, 1922, are redescribed on the basis of new material from twaite shad, Alosa fallax (Lacépède, 1803), from England and burbot, Lota lota (Linnaeus, 1758), from Russia, respectively. The tapeworms are compared with two other species of the genus, E. crassum (Bloch, 1779) and E. salvelini (Schrank, 1790), common parasites of salmonid fish in the Holarctic. The most notable differential characters are the size and the shape of the scolex (smaller and oval in E. fragile), the shape of the apical disc (four or more indentations in E. crassum), the number and size of the testes (the largest and least numerous in E. rugosum), and the position and size of the vitelline follicles (almost entirely cortical in distribution in E. fragile and E. crassum versus largely medullary in E. rugosum and E. salvelini). A comparison of species has also shown the morphological similarity of the freshwater species (E. rugosum and E. salvelini) on one hand and those of marine origin, E. fragile and E. crassum, on the other, with the latter species occurring also in fresh waters. A key to the identification of the species studied is also provided.

  3. Impact of entrainment and impingement on fish populations in the Hudson River estuary. Volume I. Entrainment-impact estimates for six fish populations inhabiting the Hudson River estuary

    SciTech Connect

    Boreman, J.; Barnthouse, L.W.; Vaughn, D.S.; Goodyear, C.P.; Christensen, S.W.; Kumar, K.D.; Kirk, B.L.; Van Winkle, W.

    1982-01-01

    This volume is concerned with the estimation of the direct (or annual) entrainment impact of power plants on populations of striped bass, white perch, Alosa spp. (blueback herring and alewife), American shad, Atlantic tomcod, and bay anchovy in the Hudson River estuary. Entrainment impact results from the killing of fish eggs, larvae, and young juveniles that are contained in the cooling water cycled through a power plant. An Empirical Transport Model (ETM) is presented as the means of estimating a conditional entrainment mortality rate (defined as the fraction of a year class which would be killed due to entrainment in the absence of any other source of mortality). Most of this volume is concerned with the estimation of several parameters required by the ETM: physical input parameters (e.g., power-plant withdrawal flow rates); the longitudinal distribution of ichthyoplankton in time and space; the duration of susceptibility of the vulnerable organisms; the W-factors, which express the ratios of densities of organisms in power plant intakes to densities of organisms in the river; and the entrainment mortality factors (f-factors), which express the probability that an organism will be killed if it is entrained. Once these values are obtained, the ETM is used to estimate entrainment impact for both historical and projected conditions.

  4. Movement and population size of American shad near a low-head lock and dam

    USGS Publications Warehouse

    Bailey, M.M.; Isely, J.J.; Bridges, W.C.

    2004-01-01

    We investigated the population size and the proportion of the population of American shad Alosa sapidissima that passed through the New Savannah Bluff Lock and Dam, a low-head lock and dam on the Savannah River in South Carolina and Georgia. We fitted 110 American shad with radio transmitters in 2001 and 2002. All but two fish moved downstream after transmitter implantation. In 2001, a smaller proportion of American shad implanted with radio transmitters earlier in the season returned to the dam than fish released later. Of the fish that returned to the dam, over 50% in 2001 and 9% in 2002 passed through the lock and continued migrating upstream. In both years, the modal daily movement distance was less than 1 km. Movements greater than 5 km/d were generally associated with fish rapidly returning upstream after their initial downstream movement. Continuous diel monitoring indicated that movements greater than 0.1 km/h were more frequent at night than during the day. In both years, American shad were not uniformly distributed over the study area but were predominantly grouped just below the dam and in a relatively large pool approximately 6 km below the dam. We estimated the population size of American shad that reached the New Savannah Bluff Lock and Dam at 157,685 in 2001 and 217,077 in 2002.

  5. 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.

  6. A Bayesian spawning habitat suitability model for American shad in southeastern United States rivers

    USGS Publications Warehouse

    Hightower, Joseph E.; Harris, Julianne E.; Raabe, Joshua K.; Brownell, Prescott; Drew, C. Ashton

    2012-01-01

    Habitat suitability index models for American shad Alosa sapidissima were developed by Stier and Crance in 1985. These models, which were based on a combination of published information and expert opinion, are often used to make decisions about hydropower dam operations and fish passage. The purpose of this study was to develop updated habitat suitability index models for spawning American shad in the southeastern United States, building on the many field and laboratory studies completed since 1985. We surveyed biologists who had knowledge about American shad spawning grounds, assembled a panel of experts to discuss important habitat variables, and used raw data from published and unpublished studies to develop new habitat suitability curves. The updated curves are based on resource selection functions, which can model habitat selectivity based on use and availability of particular habitats. Using field data collected in eight rivers from Virginia to Florida (Mattaponi, Pamunkey, Roanoke, Tar, Neuse, Cape Fear, Pee Dee, St. Johns), we obtained new curves for temperature, current velocity, and depth that were generally similar to the original models. Our new suitability function for substrate was also similar to the original pattern, except that sand (optimal in the original model) has a very low estimated suitability. The Bayesian approach that we used to develop habitat suitability curves provides an objective framework for updating the model as new studies are completed and for testing the model's applicability in other parts of the species' range.

  7. Comparing historical catch rates of American shad in multifilament and monofilament nets: A step toward setting restoration targets for Virginia stocks

    USGS Publications Warehouse

    Maki, K.L.; Hoenig, J.M.; Olney, J.E.; Heisey, D.M.

    2006-01-01

    Recreational and commercial harvest of American shad Alosa sapidissima in the Virginia waters of the Chesapeake Bay and its tributaries has been prohibited since 1994. The Atlantic States Marine Fisheries Commission Shad and River Herring Management Plan requires that Virginia develop restoration targets for its shad populations, but estimates of their sizes are not available and there is little information about historic population levels. Thus, establishing restoration targets based on population size is problematic. A current spawning stock monitoring program yields catch rate information that can be compared with historic catch rate information recorded in commercial fishery logbooks from the 1950s and the 1980s. However, multifilament gill nets were used in the 1950s and monofilament nets were used in the 1980s (as well as in the current monitoring program). A Latin square design was employed to test the differences in relative fishing power of the two gear types over 2 years of seasonal sampling on the York River, Virginia. Estimates are that the monofilament nets are roughly twice as efficient as the multifilament nets. Reported catch rates in the 1950s and 1980s are roughly equivalent. However, when adjustments are made for the differences in fishing gear, catch rates for the 1950s are twice as high as those during the 1980s. These results provide valuable information for setting restoration targets for Virginia stocks of American shad. ?? Copyright by the American Fisheries Society 2006.

  8. Food of blueback herring and threadfin shad in Jocassee Reservoir, South Carolina

    USGS Publications Warehouse

    Davis, Bruce M.; Foltz, Jeffrey W.

    1991-01-01

    Threadfin shad Dorosoma petenense and blueback herring Alosa aestivalis were introduced into Jocassee Reservoir, South Carolina, in the early 1970s as prey for large piscivores. To assess the potential for trophic competition between these clupeids, we examined their diets and the extent of diet overlap in May, August, and December 1982 and February 1983. The diet of blueback herring consisted mainly of large species of cladocerans and copepods supplemented in August with Chaoborus punctipennis and young fish. Mean length of the organisms eaten by blueback herring was 1.4 mm. Threadfin shad fed on smaller species of cladocerans and copepods, as well as on rotifers and copepod nauplii. The mean length of the organisms eaten by threadfin shad was 0.4 mm, which differed significantly from the mean length of the zooplankton population in Jocassee Reservoir (0.6 mm). Phytoplankton contributed 24 and 32% of the stomach contents of threadfin shad in August and December. Bosmina longirostris was important in the diet of both species, although blueback herring showed negative selection for it. Diet overlap between the two clupeids was low on all four dates. Although we found no evidence of trophic competition between the two species in Jocassee Reservoir, we do not recommend stocking them together, because both species are voracious planktivores and blueback herring are piscivorous.

  9. Diet of juvenile and adult American Shad in the Columbia River

    USGS Publications Warehouse

    Sauter, Sally T.; Blubaugh, J; Parsley, Michael J.

    2011-01-01

    The diet of juvenile and adult American shad Alosa sapidissima captured from various locations in the Columbia River was investigated during 2007 and 2008. Collection efforts in 2007 were restricted to fish collected from existing adult and juvenile fish collection facilities located at Bonneville Dam and to adult shad captured by angling downstream from Bonneville Dam. In 2008, we used gillnets, electrofishing, beach seining, or cast nets to collect juvenile and adult shad from the saline estuary near Astoria (approximately river km 24) to just upstream from McNary Dam (approximately river km 472). We examined the stomach contents of 436 American shad captured in 2007 and 1,272 captured in 2008. Fish caught within the river were much more likely to contain food items than fish removed from fish collection facilities.


    The diet of age-0 American shad varied spatially and temporally, but was comprised primarily of crustaceans and insects. Prey diversity of age-0 American shad, as assessed by the Shannon Diversity Index, increased with decreasing distance to the estuary. Pre- and partial-spawn American shad primarily consumed Corophium spp. throughout the Columbia River; however, post-spawn adults primarily consumed gastropods upstream of McNary Dam

  10. Distribution of spawning activity by anadromous fishes in an atlantic slope drainage after removal of a low-head dam

    USGS Publications Warehouse

    Burdick, S.M.; Hightower, J.E.

    2006-01-01

    In 1998, the Quaker Neck Dam was removed from the Neuse River near Goldsboro, North Carolina, restoring access to more than 120 km of potential main-stem spawning habitat and 1,488 km of potential tributary spawning habitat to anadromous fishes. We used plankton sampling and standardized electrofishing to examine the extent to which anadromous fishes utilized this restored spawning habitat in 2003 and 2004. Evidence of spawning activity was detected upstream of the former dam site for three anadromous species: American shad Alosa sapidissima, hickory shad A. mediocris, and striped bass Morone saxatilis. The percentages of eggs and larvae collected in the restored upstream habitat were greater in 2003, when spring flows were high, than in 2004. River reaches where spawning occurred were estimated from egg stage and water velocity data. Spawning of American shad and striped bass occurred primarily in main-stem river reaches that were further upstream during the year of higher spring flows. Hickory shad generally spawned in downstream reaches and in tributaries above and below the former dam site. These results demonstrate that anadromous fishes will take advantage of upper basin spawning habitat restored through dam removal as long as instream flows are adequate to facilitate upstream migration.

  11. American shad migratory behavior, weight loss, survival, and abundance in a North Carolina River following dam removals

    USGS Publications Warehouse

    Raabe, Joshua K.; Hightower, Joseph E.

    2014-01-01

    Despite extensive management and research, populations of American Shad Alosa sapidissima have experienced prolonged declines, and uncertainty about the underlying mechanisms causing these declines remains. In the springs of 2007 through 2010, we used a resistance board weir and PIT technology to capture, tag, and track American Shad in the Little River, North Carolina, a tributary to the Neuse River with complete and partial removals of low-head dams. Our objectives were to examine migratory behaviors and estimate weight loss, survival, and abundance during each spawning season. Males typically immigrated earlier than females and also used upstream habitat at a higher percentage, but otherwise exhibited relatively similar migratory patterns. Proportional weight loss displayed a strong positive relationship with both cumulative water temperature during residence time and number of days spent upstream, and to a lesser extent, minimum distance the fish traveled in the river. Surviving emigrating males lost up to 30% of their initial weight and females lost up to 50% of their initial weight, indicating there are potential survival thresholds. Survival for the spawning season was low and estimates ranged from 0.07 to 0.17; no distinct factors (e.g., sex, size, migration distance) that could contribute to survival were detected. Sampled and estimated American Shad abundance increased from 2007 through 2009, but was lower in 2010. Our study provides substantial new information about American Shad spawning that may aid restoration efforts.

  12. Estimating mortality rates of adult fish from entrainment through the propellers of river towboats

    USGS Publications Warehouse

    Gutreuter, S.; Dettmers, J.M.; Wahl, David H.

    2003-01-01

    We developed a method to estimate mortality rates of adult fish caused by entrainment through the propellers of commercial towboats operating in river channels. The method combines trawling while following towboats (to recover a fraction of the kills) and application of a hydrodynamic model of diffusion (to estimate the fraction of the total kills collected in the trawls). The sampling problem is unusual and required quantifying relatively rare events. We first examined key statistical properties of the entrainment mortality rate estimators using Monte Carlo simulation, which demonstrated that a design-based estimator and a new ad hoc estimator are both unbiased and converge to the true value as the sample size becomes large. Next, we estimated the entrainment mortality rates of adult fishes in Pool 26 of the Mississippi River and the Alton Pool of the Illinois River, where we observed kills that we attributed to entrainment. Our estimates of entrainment mortality rates were 2.52 fish/km of towboat travel (80% confidence interval, 1.00-6.09 fish/km) for gizzard shad Dorosoma cepedianum, 0.13 fish/km (0.00-0.41) for skipjack herring Alosa chrysochloris, and 0.53 fish/km (0.00-1.33) for both shovelnose sturgeon Scaphirhynchus platorynchus and smallmouth buffalo Ictiobus bubalus. Our approach applies more broadly to commercial vessels operating in confined channels, including other large rivers and intracoastal waterways.

  13. Passage of American shad: paradigms and realities

    USGS Publications Warehouse

    Haro, Alex; Castro-Santos, Theodore

    2012-01-01

    Despite more than 250 years of development, the passage of American shad Alosa sapidissima at dams and other barriers frequently remains problematic. Few improvements in design based on knowledge of the swimming, schooling, and migratory behaviors of American shad have been incorporated into passage structures. Large-scale technical fishways designed for the passage of adult salmonids on the Columbia River have been presumed to have good performance for American shad but have never been rigorously evaluated for this species. Similar but smaller fishway designs on the East Coast frequently have poor performance. Provision of effective downstream passage for both juvenile and postspawning adult American shad has been given little consideration in most passage projects. Ways to attract and guide American shad to both fishway entrances and downstream bypasses remain marginally understood. The historical development of passage structures for American shad has resulted in assumptions and paradigms about American shad behavior and passage that are frequently unsubstantiated by supporting data or appropriate experimentation. We propose that many of these assumptions and paradigms are either unfounded or invalid and that significant improvements to American shad upstream and downstream passage can be made via a sequential program of behavioral experimentation, application of experimental results to the physical and hydraulic design of new structures, and controlled tests of large-scale prototype structures in the laboratory and field.

  14. Video evaluation of passage efficiency of American shad and sea lamprey in a modified Ice Harbor fishway

    USGS Publications Warehouse

    Haro, A.; Kynard, B.

    1997-01-01

    Movement and behavior of adult American shad Alosa sapidissima and sea lamprey Petromyzon marinus were monitored by closed-circuit video at several locations within a modified Ice Harbor fishway. American shad ascended and descended the fishway exclusively by surface weirs, while sea lampreys used both surface weirs and submerged orifices. Upstream movement of American shad during the day was higher than at night at both lower and middle fishway observation sites. Peak downstream movement of American shad at both locations was associated with decreasing light levels in the evening. Sea lampreys moved primarily at night at the lower and middle fishway sites. Mean daily passage efficiency was low (1% for American shad, -2% for sea lamprey) at the lower fishway surface weir, but passage efficiency at the middle fishway surface weir was moderate (70% for American shad, 35% for sea lamprey). High water velocity, air entrainment, and turbulence of the modified Ice Harbor fishway design appeared to inhibit American shad and sea lamprey passage by disrupting upstream migratory motivation and visual and rheotactic orientation.

  15. Effects of pressure reductions in a proposed siphon water lift system at St. Stephen Dam, South Carolina, on mortality rates of juvenile American shad and blueback herring. Technical report

    SciTech Connect

    Nestler, J.M.; Schilt, C.R.; Jones, D.P.

    1998-09-01

    This report presents results of studies to predict the mortality rate of juvenile blueback herring (Alosa aestivalis) and American shad (A. sapidissima) associated with reduced pressure as they pass downstream through a proposed siphon water lift system at St. Stephen Dam, South Carolina. The primary function of the siphon is to increase attracting flow to better guide upstream migrating adult herring of both species into the existing fish lift for upstream passage. The US Army Engineer District, Charleston, wishes to consider the siphon as an alternative bypass route through the dam for downstream migrating juvenile and adult herring. A pressure-reduction testing system that emulates some of the pressure characteristics of the siphon was used to determine the approximate percentage of juvenile fishes that could be reasonably expected to be killed passing through the reduced pressures anticipated for the siphon water lift system. The testing system could duplicate the range of pressure change anticipated for the siphon lift system but could not obtain pressures lower than 4.1 psi, whereas pressures for some design alternatives may approach the theoretical minimum pressure of 0.0 psi. Study results indicate that the mortality rate is probably about 20 percent. Power analysis indicates that mortality rate above 30 percent is unlikely. Conducting additional mortality studies is recommended to refine predicted mortality rates. Measures should be taken to prevent juvenile fish from entering the siphon lift system if excessive mortality rates are observed.

  16. Effects of feeding ration on larval swimming speed and responsiveness to predator attacks: Implications for cohort survival

    USGS Publications Warehouse

    Chick, J.H.; Van Den Avyle, M.J.

    2000-01-01

    We conducted laboratory experiments to examine the effects of feeding ration on the routine swimming speed of larval striped bass (Morone saxatilis) and their responsiveness to simulated-predator attacks. Striped bass were reared in low (7 prey ?? L-1), medium (354 prey ?? L-1), or high (740 prey ?? L-1) prey treatments from age 4 to 14 days posthatch. Larvae reared in the low-prey treatment had slower routine swimming speeds and shorter reactive distances and were less responsive to simulated-predator attacks. These differences were most pronounced after age 10 and appeared to be an effect of deteriorating larval condition rather than an effect of size. Simulation models were constructed for two potential fish predators, Alosa aestivalis and Pomoxis nigromaculatus, to examine how variation in growth rate, swimming speed, and responsiveness to predator attacks might influence mortality rate. Our simulations predicted that cohort mortality rate would decrease with increasing larval growth rates, even though faster routine swimming speed and growth rate increased encounter rates with predators. The influence of larval growth rate and responsiveness on mortality rate varied between the two predators, but cohorts experiencing no growth always had the greatest mortality rate.

  17. Atlantic coast feeding habits of striped bass: A synthesis supporting a coast-wide understanding of trophic biology

    USGS Publications Warehouse

    Walter, J. F.; Overton, A.S.; Ferry, K.H.; Mather, M. E.

    2003-01-01

    The recent increase in the Atlantic coast population of striped bass, Morone saxatilis (Walbaum), prompted managers to re-evaluate their predatory impact. Published and unpublished diet data for striped bass on the Atlantic Coast of North America were examined for geographical, ontogenetic and seasonal patterns in the diet and to assess diet for this species. Diets of young-of-the-year (YOY) striped bass were similar across the Upper Atlantic (UPATL), Chesapeake and Delaware Bays (CBDEL) and North Carolina (NCARO) areas of the Atlantic coast where either fish or mysid shrimp dominate the diet. For age one and older striped bass, cluster analysis partitioned diets based on predominance of either Atlantic menhaden, Brevoortia tyrannus (Latrobe), characteristic of striped bass from the CBDEL and NCARO regions, or non-menhaden fishes or invertebrates, characteristic of fish from the UPATL, in the diet. The predominance of invertebrates in the diets of striped bass in the UPATL region can be attributed to the absence of several important species groups in Northern waters, particularly sciaenid fishes, and to the sporadic occurrences of Atlantic menhaden to UPATL waters. In all regions, across most seasons and in most size classes of striped bass, the clupeiod fishes; menhaden, anchovies (Anchoa spp.) and river herrings (Alosa spp,) and Atlantic herring, Clupea harengus L., dominated the diets of striped bass above the first year of life.

  18. Potential strategies for recovery of lake whitefish and lake herring stocks in eastern Lake Erie

    USGS Publications Warehouse

    Oldenburg, K.; Stapanian, M.A.; Ryan, P.A.; Holm, E.

    2007-01-01

    Lake Erie sustained large populations of ciscoes (Salmonidae: Coregoninae) 120 years ago. By the end of the 19th century, abundance of lake whitefish (Coregonus clupeaformis) had declined drastically. By 1925, the lake herring (a cisco) population (Coregonus artedii) had collapsed, although a limited lake herring fishery persisted in the eastern basin until the 1950s. In the latter part of the 20th century, the composition of the fish community changed as oligotrophication proceeded. Since 1984, a limited recovery of lake whitefish has occurred, however no recovery was evident for lake herring. Current ecological conditions in Lake Erie probably will not inhibit recovery of the coregonine species. Recovery of walleye (Sander vitreus) and efforts to rehabilitate the native lake trout (Salvelinus namaycush) in Lake Erie will probably assist recovery because these piscivores reduce populations of alewife (Alosa psuedoharengus) and rainbow smelt (Osmerus mordax), which inhibit reproductive success of coregonines. Although there are considerable spawning substrates available to coregonine species in eastern Lake Erie, eggs and fry would probably be displaced by storm surge from most shoals. Site selection for stocking or seeding of eggs should consider the reproductive life cycle of the stocked fish and suitable protection from storm events. Two potential sites in the eastern basin have been identified. Recommended management procedures, including commercial fisheries, are suggested to assist in recovery. Stocking in the eastern basin of Lake Erie is recommended for both species, as conditions are adequate and the native spawning population in the eastern basin is low. For lake herring, consideration should be given to match ecophenotypes as much as possible. Egg seeding is recommended. Egg seeding of lake whitefish should be considered initially, with fingerling or yearling stocking suggested if unsuccessful. Spawning stocks of whitefish in the western basin of Lake

  19. Prey of nesting ospreys on the Willamette and Columbia Rivers, Oregon and Washington

    USGS Publications Warehouse

    Johnson, B.L.; Kaiser, J.L.; Henny, C.J.; Grove, R.A.

    2008-01-01

    To more effectively use ospreys as a biomonitoring tool and to better assess contaminant pathways, the diet of nesting ospreys (Pandion haliaetus) was studied along the lower Columbia and upper mainstem Willamette rivers by evaluating prey remains collected from wire baskets constructed under artificial feeding perches installed near nest sites and from the ground beneath natural feeding perches and nests. Prey remains from 1997-2004 on the Columbia River and 1993 (previously published) and 2001 on the Willamette River were evaluated and compared. Largescale suckers (Catostomus macrocheilus) were the predominate fish species identified in collections from the Columbia River (61.5% [84.3% biomass]) and Willamette River (76.0% [92.7% biomass]). Prey fish diversity, when based only on ground collections, was higher in the Columbia (2.45) than the Willamette river (1.92) (P = 0.038). Prey fish diversity in collections from the Willamette River did not differ between this study (2001) and previous study (1993) (P = 0.62). Fishbones recovered in wire baskets are likely more representative of osprey diet compared to bones recovered from the ground, because prey diversity was higher among basket samples compared to ground collections (wire basket diversity = 5.25 vs. ground collection diversity = 2.45, P = 0.011). Soft-boned salmonids (Oncorhynchus spp.), American shad (Alosa sapidissima), and mountain whitefish (Prosopium williamsoni) were probably underrepresented in collections obtained from the ground. Study results suggest that baskets provide a better method for assessing osprey diet than other indirect methods. These findings augment available osprey food-habits information and provide additional biological and ecological information to better assess potential impacts of various environmental contaminants on nesting ospreys.

  20. Assessing distribution of migratory fishes and connectivity following complete and partial dam removals in a North Carolina River

    USGS Publications Warehouse

    Raabe, Joshua K.; Hightower, Joseph E.

    2014-01-01

    Fish, especially migratory species, are assumed to benefit from dam removals that restore connectivity and access to upstream habitat, but few studies have evaluated this assumption. Therefore, we assessed the movement of migratory fishes in the springs of 2008 through 2010 and surveyed available habitat in the Little River, North Carolina, a tributary to the Neuse River, after three complete dam removals and one partial (notched) dam removal. We tagged migratory fishes with PIT tags at a resistance-board weir located at a dam removal site (river kilometer [rkm] 3.7) and followed their movements with an array of PIT antennas. The river-wide distribution of fish following removals varied by species. For example, 24–31% of anadromous American Shad Alosa sapidissima, 45–49% of resident Gizzard Shad Dorosoma cepedianum, and 4–11% of nonnative Flathead CatfishPylodictis olivaris passed the dam removal site at rkm 56 in 2009 and 2010. No preremoval data were available for comparison, but reach connectivity appeared to increase as tagged individuals passed former dam sites and certain individuals moved extensively both upstream and downstream. However, 17–28% did not pass the partially removed dam at rkm 7.9, while 20–39% of those that passed remained downstream for more than a day before migrating upstream. Gizzard Shad required the deepest water to pass this notched structure, followed by American Shad then Flathead Catfish. Fish that passed the notched dam accessed more complex habitat (e.g., available substrate size-classes) in the middle and upper reaches. The results provide strong support for efforts to restore currently inaccessible habitat through complete removal of derelict dams.

  1. Demographic population model for American shad: will access to additional habitat upstream of dams increase population sizes?

    USGS Publications Warehouse

    Harris, Julianne E.; Hightower, Joseph E.

    2012-01-01

    American shad Alosa sapidissima are in decline in their native range, and modeling possible management scenarios could help guide their restoration. We developed a density-dependent, deterministic, stage-based matrix model to predict the population-level results of transporting American shad to suitable spawning habitat upstream of dams on the Roanoke River, North Carolina and Virginia. We used data on sonic-tagged adult American shad and oxytetracycline-marked American shad fry both above and below dams on the Roanoke River with information from other systems to estimate a starting population size and vital rates. We modeled the adult female population over 30 years under plausible scenarios of adult transport, effective fecundity (egg production), and survival of adults (i.e., to return to spawn the next year) and juveniles (from spawned egg to age 1). We also evaluated the potential effects of increased survival for adults and juveniles. The adult female population size in the Roanoke River was estimated to be 5,224. With no transport, the model predicted a slow population increase over the next 30 years. Predicted population increases were highest when survival was improved during the first year of life. Transport was predicted to benefit the population only if high rates of effective fecundity and juvenile survival could be achieved. Currently, transported adults and young are less likely to successfully out-migrate than individuals below the dams, and the estimated adult population size is much smaller than either of two assumed values of carrying capacity for the lower river; therefore, transport is not predicted to help restore the stock under present conditions. Research on survival rates, density-dependent processes, and the impacts of structures to increase out-migration success would improve evaluation of the potential benefits of access to additional spawning habitat for American shad.

  2. Diel and distributional abundance patterns of fish embryos and larvae in the lower Columbia and Deschutes rivers

    USGS Publications Warehouse

    Gadomski, D.M.; Barfoot, C.A.

    1998-01-01

    Diel and distributional abundance patterns of free embryos and larvae of fishes in the lower Columbia River Basin were investigated. Ichthyoplankton samples were collected in 1993 during day and night in the main-channel and a backwater of the lower Columbia River, and in a tributary, the Deschutes River. Fish embryos and larvae collected in the main-channel Columbia River were primarily (85.6%) of native taxa (peamouth Mylocheilus caurinus, northern squawfish Ptychocheilus oregonensis, suckers Catostomus spp., and sculpins Cottus spp.), with two introduced species (American shad Alosa sapidissima and common carp Cyprinus carpio) comprising a smaller percentage of the catch (13.3%). Similarly, in the Deschutes River native taxa [lampreys (Petromyzontidae), minnows (Cyprinidae), and suckers Catostomus spp.] dominated collections (99.5% of the catch). In contrast, 83.5% of embryos and larvae in the Columbia River backwater were of introduced taxa [American shad, common carp, and sunfishes (Centrarchidae)]. In all locations, all dominant taxa except sculpins were collected in significantly greater proportions at night. Taxon-specific differences in proportions of embryos and larvae collected at night can in some instances be related to life history styles. In the main-channel Columbia River, northern squawfish and peamouth were strongly nocturnal and high proportions still had yolksacs, suggesting that they had recently hatched and were drifting downriver to rearing areas. In contrast, sculpin abundances were similar during day and night, and sculpins mostly had depleted yolksacs, indicating sculpins were feeding and rearing in offshore limnetic habitats. Taxon-specific diel abundance patterns and their causes must be considered when designing effective sampling programs for fish embryos and larvae.

  3. Movement Patterns of American Shad Transported Upstream of Dams on The Roanoke River, North Carolina and Virginia

    USGS Publications Warehouse

    Harris, Julianne E.; Hightower, J.E.

    2011-01-01

    American shad Alosa sapidissima are in decline throughout much of their native range as a result of overfishing, pollution, and habitat alteration in coastal rivers where they spawn. One approach to restoration in regulated rivers is to provide access to historical spawning habitat above dams through a trap-and-transport program. We examined the initial survival, movement patterns, spawning, and downstream passage of sonic-tagged adult American shad transported to reservoir and riverine habitats upstream of hydroelectric dams on the Roanoke River, North Carolina and Virginia, during 2007–2009. Average survival to release in 2007–2008 was 85%, but survival decreased with increasing water temperature. Some tagged fish released in reservoirs migrated upstream to rivers; however, most meandered back and forth within the reservoir. A higher percentage of fish migrated through a smaller (8,215-ha) than a larger (20,234-ha) reservoir, suggesting that the population-level effects of transport may depend on upper basin characteristics. Transported American shad spent little time in upper basin rivers but were there when temperatures were appropriate for spawning. No American shad eggs were collected during weekly plankton sampling in upper basin rivers. The estimated initial survival of sonic-tagged American shad after downstream passage through each dam was 71–100%; however, only 1% of the detected fish migrated downstream through all three dams and many were relocated just upstream of a dam late in the season. Although adult American shad were successfully transported to upstream habitats in the Roanoke River basin, under present conditions transported individuals may have reduced effective fecundity and postspawning survival compared with nontransported fish that spawn in the lower Roanoke River.

  4. Movement and spawning of American shad transported above dams on the Roanoke River, North Carolina and Virginia

    USGS Publications Warehouse

    Harris, Julianne E.; Hightower, Joseph E.

    2011-01-01

    American shad Alosa sapidissima are in decline throughout much of their native range as a result of overfishing, pollution, and habitat alteration in coastal rivers where they spawn. One approach to restoration in regulated rivers is to provide access to historical spawning habitat above dams through a trap-and-transport program. We examined the initial survival, movement patterns, spawning, and downstream passage of sonic-tagged adult American shad transported to reservoir and riverine habitats upstream of hydroelectric dams on the Roanoke River, North Carolina and Virginia, during 2007–2009. Average survival to release in 2007–2008 was 85%, but survival decreased with increasing water temperature. Some tagged fish released in reservoirs migrated upstream to rivers; however, most meandered back and forth within the reservoir. A higher percentage of fish migrated through a smaller (8,215-ha) than a larger (20,234-ha) reservoir, suggesting that the population-level effects of transport may depend on upper basin characteristics. Transported American shad spent little time in upper basin rivers but were there when temperatures were appropriate for spawning. No American shad eggs were collected during weekly plankton sampling in upper basin rivers. The estimated initial survival of sonic-tagged American shad after downstream passage through each dam was 71–100%; however, only 1% of the detected fish migrated downstream through all three dams and many were relocated just upstream of a dam late in the season. Although adult American shad were successfully transported to upstream habitats in the Roanoke River basin, under present conditions transported individuals may have reduced effective fecundity and postspawning survival compared with nontransported fish that spawn in the lower Roanoke River.

  5. Fall diets of red-breasted merganser (Mergus serrator) and walleye (Sander vitreus) in Sandusky Bay and adjacent waters of western Lake Erie

    USGS Publications Warehouse

    Bur, M.T.; Stapanian, M.A.; Bernhardt, G.; Turner, M.W.

    2008-01-01

    Although published studies indicate the contrary, there is concern among many sport anglers that migrating red-breasted mergansers (Mergus serrator) and other waterbirds pose a competitive threat to sport fish species such as walleye (Sander vitreus) in Lake Erie. We quantified the diet of autumn-migrant mergansers and walleye during 1998-2000 in Sandusky Bay and adjacent waters of western Lake Erie. We hypothesized that the diets of both predators would be similar in species composition, but because of different foraging ecologies their diets would differ markedly in size of prey consumed. In addition to predator samples, we used trawl data from the same general area as an index of prey availability. We found that mergansers fed almost exclusively on fish (nine species). Gizzard shad (Dorosoma cepedianum), emerald shiner (Notropis atherinoides) and round goby (Neogobius melanostomus) were consumed in the greatest numbers, most frequently and comprised the greatest biomass. Walleye fed exclusively on fish: gizzard shad, alewife (Alosa psuedoharengus) and emerald shiner were consumed in the greatest numbers, most frequently and comprised the greatest biomass. Diet overlap between mergansers and walleye was 67% by weight and 66% by species frequency. Mean total lengths of gizzard shad, emerald shiner and round goby found in walleye stomachs exceeded those captured in trawls by 47%, on average. Mean total lengths of gizzard shad, emerald shiner and round goby were greater in walleye stomachs than in merganser stomachs. Mean total lengths of emerald shiner and round goby were less in merganser stomachs than in trawls. Our results suggest that although the diets of walleye and mergansers overlapped considerably, mergansers generally consumed smaller fish than walleye. Given the abundance and diversity of prey species available, and the transient nature of mergansers on Lake Erie during migration, we conclude that competition for food between these species is minimal.

  6. Identification of American shad spawning sites and habitat use in the Pee Dee River, North Carolina and South Carolina

    USGS Publications Warehouse

    Harris, Julianne E.; Hightower, Joseph E.

    2011-01-01

    We examined spawning site selection and habitat use by American shad Alosa sapidissima in the Pee Dee River, North Carolina and South Carolina, to inform future management in this flow-regulated river. American shad eggs were collected in plankton tows, and the origin (spawning site) of each egg was estimated; relocations of radio-tagged adults on spawning grounds illustrated habitat use and movement in relation to changes in water discharge rates. Most spawning was estimated to occur in the Piedmont physiographic region within a 25-river-kilometer (rkm) section just below the lowermost dam in the system; however, some spawning also occurred downstream in the Coastal Plain. The Piedmont region has a higher gradient and is predicted to have slightly higher current velocities and shallower depths, on average, than the Coastal Plain. The Piedmont region is dominated by large substrates (e.g., boulders and gravel), whereas the Coastal Plain is dominated by sand. Sampling at night (the primary spawning period) resulted in the collection of young eggs (≤1.5 h old) that more precisely identified the spawning sites. In the Piedmont region, most radio-tagged American shad remained in discrete areas (average linear range = 3.6 rkm) during the spawning season and generally occupied water velocities between 0.20 and 0.69 m/s, depths between 1.0 and 2.9 m, and substrates dominated by boulder or bedrock and gravel. Tagged adults made only small-scale movements with changes in water discharge rates. Our results demonstrate that the upstream extent of migration and an area of concentrated spawning occur just below the lowermost dam. If upstream areas have similar habitat, facilitating upstream access for American shad could increase the spawning habitat available and increase the population's size.

  7. Effect of low-head lock and dam structures on migration and spawning of American shad and striped bass in the Cape Fear River, North Carolina

    USGS Publications Warehouse

    Smith, Joseph A.; Hightower, Joseph E.

    2012-01-01

    Anadromous fish populations within the Cape Fear River, North Carolina, have declined substantially since the late 1800s. Three low-head lock-and-dam (LD) structures on the river (LD-1–3) contributed to this decline by limiting access to upstream spawning habitat. We used egg sampling and sonic telemetry to examine the effects of the LD structures on migration and spawning activity of American shad Alosa sapidissima and striped bassMorone saxatilis. Egg distribution and stage of development suggested that most of the American shad spawning took place downstream from the lowermost structure, LD-1. The predicted mean density of stage-1 American shad eggs at a water temperature of 21°C was 895 eggs/1,000 m3 (95% credible interval [CI] = 800–994) below LD-1; 147 eggs/1,000 m3 (95% CI = 103–197) below LD-2; and 32 eggs/1,000 m3 (95% CI = 17–49) below the uppermost structure, LD-3. The probability of capturing a stage-1 American shad egg was strongly dependent on water temperature and hour of egg collection. Transmitter detections for 20 sonic-tagged American shad and 20 striped bass in 2008 showed that for both species, the majority of fish moved upstream of LD-1; 35% of American shad and 25% of striped bass migrated upstream of LD-3. Based on passage rates at the three LD structures, American shad would be expected to be most abundant downstream of LD-1 and upstream of LD-3. For striped bass, the river section between LD-2 and LD-3 had the highest egg collections and highest predicted proportion of the run. In combination, these results demonstrate that the locking program provides some access to historical spawning habitat, although further improvements in fish passage could benefit both species.

  8. The effects of juvenile American shad planktivory on zooplankton production in Columbia River food webs

    USGS Publications Warehouse

    Haskell, Craig A.; Tiffan, Kenneth F.; Rondorf, Dennis W.

    2013-01-01

    Columbia River reservoirs support a large population of nonnative American Shad Alosa sapidissima that consume the zooplankton that native fishes also rely on. We hypothesized that the unprecedented biomass of juvenile American Shad in John Day Reservoir is capable of altering the zooplankton community if these fish consume a large portion of the zooplankton production. We derived taxon-specific estimates of zooplankton production using field data and a production model from the literature. Empirical daily ration was estimated for American Shad and expanded to population-level consumption using abundance and biomass data from hydroacoustic surveys. Daphnia spp. production was high in early summer but declined to near zero by September as shad abundance increased. American Shad sequentially consumed Daphnia spp., copepods, and Bosmina spp., which tracked the production trends of these taxa. American Shad evacuation rates ranged from 0.09 to 0.24/h, and daily rations ranged from 0.008 to 0.045 g·g−1·d−1 (dry weight) over all years. We observed peak American Shad biomass (45.2 kg/ha) in 1994, and daily consumption (1.6 kg/ha) approached 30% (5.3 kg/ha) of zooplankton production. On average, American Shad consumed 23.6% of the available zooplankton production (range, <1–83%). The changes in the zooplankton community are consistent with a top-down effect of planktivory by American Shad associated with their unprecedented biomass and consumption, but the effects are likely constrained by temperature, nutrient flux, and the seasonal production patterns of zooplankton in John Day Reservoir. American Shad add to the planktivory exerted by other species like Neomysis mercedis to reduce the capacity of the reservoir to support other planktivorous fishes. The introduction of American Shad and other nonnative species will continue to alter the food web in John Day Reservoir, potentially affecting native fishes, including Pacific salmon Oncorhynchus spp.

  9. To stock or not to stock? Assessing restoration potential of a remnant American shad spawning run with hatchery supplementation

    USGS Publications Warehouse

    Bailey, Michael M.; Zydlewski, Joseph

    2013-01-01

    Hatchery supplementation has been widely used as a restoration technique for American Shad Alosa sapidissima on the East Coast of the USA, but results have been equivocal. In the Penobscot River, Maine, dam removals and other improvements to fish passage will likely reestablish access to the majority of this species’ historic spawning habitat. Additional efforts being considered include the stocking of larval American Shad. The decision about whether to stock a river system undergoing restoration should be made after evaluating the probability of natural recolonization and examining the costs and benefits of potentially accelerating recovery using a stocking program. However, appropriate evaluation can be confounded by a dearth of information about the starting population size and age structure of the remnant American Shad spawning run in the river. We used the Penobscot River as a case study to assess the theoretical sensitivity of recovery time to either scenario (stocking or not) by building a deterministic model of an American Shad population. This model is based on the best available estimates of size at age, fecundity, rate of iteroparity, and recruitment. Density dependence was imposed, such that the population reached a plateau at an arbitrary recovery goal of 633,000 spawning adults. Stocking had a strong accelerating effect on the time to modeled recovery (as measured by the time to reach 50% of the recovery goal) in the base model, but stocking had diminishing effects with larger population sizes. There is a diminishing return to stocking when the starting population is modestly increased. With a low starting population (a spawning run of 1,000), supplementation with 12 million larvae annually accelerated modeled recovery by 12 years. Only a 2-year acceleration was observed if the starting population was 15,000. Such a heuristic model may aid managers in assessing the costs and benefits of stocking by incorporating a structured decision framework.

  10. American shad in the Columbia River

    USGS Publications Warehouse

    Petersen, J.H.; Hinrichsen, R.A.; Gadomski, D.M.; Feil, D.H.; Rondorf, D.W.

    2003-01-01

    American shad Alosa sapidissima from the Hudson River, New York, were introduced into the Sacramento River, California, in 1871 and were first observed in the Columbia River in 1876. American shad returns to the Columbia River increased greatly between 1960 and 1990, and recently 2-4 million adults have been counted per year at Bonneville Dam, Oregon and Washington State (river kilometer 235). The total return of American shad is likely much higher than this dam count. Returning adults migrate as far as 600 km up the Columbia and Snake rivers, passing as many as eight large hydroelectric dams. Spawning occurs primarily in the lower river and in several large reservoirs. A small sample found returning adults were 2-6 years old and about one-third of adults were repeat spawners. Larval American shad are abundant in plankton and in the nearshore zone. Juvenile American shad occur throughout the water column during night, but school near the bottom or inshore during day. Juveniles consume a variety of zooplankton, but cyclopoid copepods were 86% of the diet by mass. Juveniles emigrate from the river from August through December. Annual exploitation of American shad by commercial and recreational fisheries combined is near 9% of the total count at Bonneville Dam. The success of American shad in the Columbia River is likely related to successful passage at dams, good spawning and rearing habitats, and low exploitation. The role of American shad within the aquatic community is poorly understood. We speculate that juveniles could alter the zooplankton community and may supplement the diet of resident predators. Data, however, are lacking or sparse in some areas, and more information is needed on the role of larval and juvenile American shad in the food web, factors limiting adult returns, ocean distribution of adults, and interactions between American shad and endangered or threatened salmonids throughout the river. ?? 2003 by the American Fisheries Society.

  11. Understanding the influence of predation by introduced fishes on juvenile salmonids in the Columbia River Basin: Closing some knowledge gaps. Interim Report of Research 2010

    USGS Publications Warehouse

    Rose, Brien P.; Hansen, Gabriel S.; Mesa, Matthew G.

    2011-01-01

    In response to these recent concerns about the potential predatory impact of non-native piscivores on salmon survival, the Bonneville Power Administration (BPA) and the Columbia Basin Fish and Wildlife Authority (CBFWA) co-hosted a workshop to address predation on juvenile salmonids in the CRB by non-native fish (Halton 2008). The purpose of the workshop was to review, evaluate, and develop strategies to reduce predation by non-native fishes on juvenile salmonids. In the end, discussion at the workshop and at subsequent meetings considered two potential ideas to reduce predation by non-native fish on juvenile salmonids; (1) understanding the role of juvenile American shad Alosa sapidissima in the diet of non-native predators in the fall; and (2) the effects of localized, intense reductions of smallmouth bass in areas of particularly high salmonid predation. In this report, we describe initial efforts to understand the influence of juvenile American shad as a prey item for introduced predators in the middle Columbia River. Our first objective, addressed in Chapter 1, was to evaluate the efficacy of nonlethal methods to describe the physiological condition of smallmouth bass, walleye, and channel catfish from late summer through late fall. Such information will be used to understand the contribution of juvenile American shad to the energy reserves of predaceous fish prior to winter. In Chapter 2, we describe the results of some limited sampling to document the food habits of smallmouth bass, walleye, and channel catfish in three reservoirs of the middle Columbia River during late fall. Collectively, we hope to increase our understanding of the contribution of juvenile American shad to the diets of introduced predators and the contribution of this diet to their energy reserves, growth, and perhaps over-winter survival. Managers should be able to use this information for deciding whether to control the population of American shad in the CRB or for managing introduced

  12. Survival Estimates for Juvenile Fish Subjected to a Laboratory-Generated Shear Environment

    SciTech Connect

    Neitzel, Duane A.; Dauble, Dennis D.; Cada, G. F.; Richmond, Marshall C.; Guensch, Greg R.; Mueller, Robert P.; Abernethy, Cary S.; Amidan, Brett G.

    2004-03-01

    Juvenile rainbow trout and steelhead Oncorhynchus mykiss, spring and fall chinook salmon O. tshawytscha, and American shad Alosa sapidissima were exposed to shear environments in the laboratory to determine the rate of strain that would kill or injure them. Fish were exposed to a submerged jet of water with exit velocities adjustable from 0 to 21.3 m/sec. The exposure strain rates for our tests ranged from 0 to about 1100 sec-1. The greatest strain rate tested is beyond rates expected in most natural fish habitat or during passage through the turbine intake of a hydroelectric dam. The rate of strain experienced by test fish varied based on a change in distance or scale of 1.8 cm, the approximate width of the fish tested. Turbulence intensity in the area of the jet where fish were subjected to the shear environment was +3 to 6% of the estimated exposure strain rate. Injuries and mortalities increased with increasing strain rates. There were no significant injuries to any fish subjected to rates of strain !U500 sec-1. American shad were the most susceptible to injury after being subjected to a shear environment while steelhead and rainbow trout were the most resistant. Fish exposed head first to the jet had higher injury/mortality rates than fish introduced tail first. Our studies reinforce past conclusions that a one-time exposure to shear environments exceeding a change in velocity of 15 m/sec over 1.8 cm is harmful to juvenile fish. The associated exposure strain rate for these velocities is ~850 sec-1 at a measurement scale of Dy = 1.8 cm.

  13. Spawning habitat selection of hickory shad

    USGS Publications Warehouse

    Harris, Julianne E.; Hightower, J.E.

    2011-01-01

    We examined the spawning habitat selectivity of hickory shad Alosa mediocris, an anadromous species on the Atlantic coast of North America. Using plankton tows and artificial substrates (spawning pads), we collected hickory shad eggs in the Roanoke River, North Carolina, to identify spawning timing, temperature, and microhabitat use. Hickory shad eggs were collected by both sampling gears in March and April. The results from this and three other studies in North Carolina indicate that spawning peaks at water temperatures between 12.0??C and 14.9??C and that approximately 90% occurs between 11.0??C and 18.9??C. Hickory shad eggs were collected in run and riffle habitats. Water velocity and substrate were significantly different at spawning pads with eggs than at those without eggs, suggesting that these are important microhabitat factors for spawning. Hickory shad eggs were usually collected in velocities of at least 0.1 m/s and on all substrates except those dominated by silt. Eggs were most abundant on gravel, cobble, and boulder substrates. Hickory shad spawned further upstream in years when water discharge rates at Roanoke Rapids were approximately average during March and April (2005 and 2007), as compared with a severe drought year (2006), suggesting that water flows may affect not only spawning site selection but also the quantity and quality of spawning habitat available at a macrohabitat scale. Using our field data and a Bayesian approach to resource selection analysis, we developed a preliminary habitat suitability model for hickory shad. This Bayesian approach provides an objective framework for updating the model as future studies of hickory shad spawning habitat are conducted. ?? American Fisheries Society 2011.

  14. Assessment of fish abundance and species composition at selected sites in South Dakota: an overview

    USGS Publications Warehouse

    Harwood, Alison

    2010-01-01

    The U.S. Geological Survey (USGS) conducted surveys of streams throughout the State of South Dakota during 2008-09 as part of the U.S. Environmental Protection Agency?s (USEPA) National Rivers and Streams Assessment (NRSA) Program. During 2008-09, as part of the stream assessment, the USGS completed surveys of fish populations and species composition at 64 sites. Fish were inventoried at 60 of the 64 sites, but not at four of the sites because water was too low to sustain fish or specific conductivity was too high to electroshock effectively. Four of the sites were surveyed in 2000-04 during the USEPA's Environmental Monitoring and Assessment Program-West (EMAP-West) project. Two wadeable sites and two boatable sites were revisited for quality-assurance/quality-control requirements. During the study, both wadeable and boatable streams were sampled using electrofishing equipment and methods. Of the 64 sites, 62 were wadeable and 2 were boatable. Procedures for sampling wadeable streams differed slightly from procedures for boatable streams. Backpack electrofishing equipment was used for wadeable streams, whereas boat electrofishing equipment was used for boatable streams. Wadeable streams also were fished in an opposite direction than boatable streams. Several species of fish were collected during the NRSA. Species diversity ranged from 0-11 species in wadeable streams and from 6-26 species in boatable streams. Many common species were sampled during the study. The most frequently sampled fish was the sand shiner (Notropis stramineus), with 609 individuals sampled. In contrast, only one heritage species, the skipjack herring (Alosa chrysochloris), was identified during 2008-09. Common anomalies found in fish caught were parasitic lesions, "black spot disease," and tumors. When comparing the fish sampling results for the four sites visited in both 2000-04 and in 2008-09, more individuals and species were collected during 2008-09 than in 2000-04 at two sites, whereas

  15. Fluktuationen der Fischfauna im Elbe-Ästuar als Indikator für ein gestörtes Ökosystem

    NASA Astrophysics Data System (ADS)

    Köhler, Angela

    1981-09-01

    During 1978, 22 fish species (in particular Anguilla anguilla L., Platichthys flesus L., Osmerus eperlanus L., Gasterosteus aculeatus L., Lampetra fluviatilis L., Alosa fallax [Lacepede], Gymnocephalus cernua L., Clupea harengus L. and Sprattus sprattus L.), sampled at the intake of the cooling system in the nuclear power plant at Brunsbüttel (Elbe estuary), were analyzed for quantities and size distribution. The data obtained were correlated to abiotic factors, such as water temperature, water outflow from the upper Elbe river, salinity and oxygen content. Spawning times and seasonal migrations of the fish species investigated corresponded to appropriate temperatures of the Elbe water. The diversity of fish species from the cooling water proved to be representative for the ichthyo-fauna of this particular estuarine area. At least 190 tons of fish per year were estimated to be annihilated by the suction of cooling water into the nuclear power plant. In spite of the progressive development of regional industries and the increasing discharges of cooling water, temperature in the estuary has remained largely unaffected up till now. The oxygen content of the heavily polluted lower Elbe river, however, has become mainly dependent on the amount of fresh water flowing from the upper Elbe river. Up to 1978, oxygen levels of 80 90 % were recorded only in the mouth of the Elbe, thus meeting the requirements for the continuous occurrence of fish species typical for this estuarine area. Varying oxygen concentrations downstream of Hamburg and at Brunsbüttel are considered to be responsible for migrations of certain fish species (mainly flounder and smelt) between the Brunsbüttel region and their habitats further upstream which were occupied before the process of industrialisation initiated. This was reflected by the size of the samples taken from various fishes. During an eventual hazard of the industrial filter plants at Brunsbüttel in May 1978 an extreme oxygen depletion

  16. Understanding the influence of predation on introduced fishes on juvenile salmonids in the Columbia River Basin: Closing some knowledge gaps. Late summer and fall diet and condition of smallmouth bass, walleye, and channel catfish in the middle Columbia River, USA. Interim Report of Research 2011.

    USGS Publications Warehouse

    Rose, Brien P.; Hansen, Gabriel S.; Weaver,; Ayers,; Van Dyke, Erick S.; Mesa, Matthew G.

    2012-01-01

    American shad Alosa sapidissima in the middle Columbia River (MCR)—a high energy food available in the summer and fall—may be contributing to the increased growth and enhanced condition of nonnative piscivores. To test this hypothesis we quantified the late summer and autumn diets of smallmouth bass Micropterus dolomieu, walleye Sander vitreus, and channel catfish Ictalurus punctatus in the three lowermost reservoirs on the Columbia River (Bonneville [BON], The Dalles [TDA], and John Day [JDA]). The diet of smallmouth bass (SMB) was fairly similar among reservoirs, with crustaceans (52–82%) and fish (13–38%) being the dominant prey groups by percent mass. Cottidae were usually the dominant fish prey in the diet of SMB at all areas and the contribution of juvenile shad ranged from 0–8.2%. Fish (mostly Cyprinidae and Cottidae) were always the dominant prey item for walleye (WAL) at all areas and at all times, ranging from 70–100% of their diet by mass. Juvenile American shad composed from 10–27% (by mass) of the diet of walleye, depending on area and month. For channel catfish (CHC), the most common prey items consumed were crustaceans (20%–80% by mass) and unidentified items (30%–80%). Fish represented a relatively small component (< 4%) of their diet. We also evaluated the condition of SMB and WAL by determining relative weights (Wr) and hepatosomatic indices (HSI). Mean Wr for SMB greater than 300 mm ranged from 0.89 to 0.94 depending on area and month and showed a significant increase from August to September for fish in BON only. Overall, mean Wr of WAL was similar at all areas, ranging from 0.89–0.91, and increased significantly from September to mid-October and November for fish in TDA only. Overall, mean HSI of SMB ranged from 1.18 to 1.48, did not differ between fish in different reservoirs, and increased significantly from September to mid-October and November for fish from the lower JDA only. Mean HSI of WAL was significantly higher in

  17. Development of a bioenergetics model for age-0 American Shad

    USGS Publications Warehouse

    Sauter, Sally T.

    2011-01-01

    Bioenergetics modeling can be used as a tool to investigate the impact of non-native age-0 American shad (Alosa sapidissima) on reservoir and estuary food webs. The model can increase our understanding of how these fish influence lower trophic levels as well as predatory fish populations that feed on juvenile salmonids. Bioenergetics modeling can be used to investigate ecological processes, evaluate alternative research hypotheses, provide decision support, and quantitative prediction. Bioenergetics modeling has proven to be extremely useful in fisheries research (Ney et al. 1993,Chips and Wahl 2008, Petersen et al. 2008). If growth and diet parameters are known, the bioenergetics model can be used to quantify the relative amount of zooplankton or insects consumed by age-0 American shad. When linked with spatial and temporal information on fish abundance, model output can guide inferential hypothesis development to demonstrate where the greatest impacts of age-0 American shad might occur.


    Bioenergetics modeling is particularly useful when research questions involve multiple species and trophic levels (e.g. plankton communities). Bioenergetics models are mass-balance equations where the energy acquired from food is partitioned between maintenance costs, waste products, and growth (Winberg 1956). Specifically, the Wisconsin bioenergetics model (Hanson et al. 1997) is widely used in fisheries science. Researchers have extensively tested, reviewed, and improved on this modeling approach for over 30 years (Petersen et al. 2008). Development of a bioenergetics model for any species requires three key components: 1) determine physiological parameters for the model through laboratory experiments or incorporate data from a closely related species, 2) corroboration of the model with growth and consumption estimates from independent research, and 3) error analysis of model parameters.


    Wisconsin bioenergetics models have been parameterized for