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Sample records for bottom trawl surveys

  1. A dataset from bottom trawl survey around Taiwan

    PubMed Central

    Shao, Kwang-Tsao; Lin, Jack; Wu, Chung-Han; Yeh, Hsin-Ming; Cheng, Tun-Yuan

    2012-01-01

    Abstract Bottom trawl fishery is one of the most important coastal fisheries in Taiwan both in production and economic values. However, its annual production started to decline due to overfishing since the 1980s. Its bycatch problem also damages the fishery resource seriously. Thus, the government banned the bottom fishery within 3 nautical miles along the shoreline in 1989. To evaluate the effectiveness of this policy, a four year survey was conducted from 2000–2003, in the waters around Taiwan and Penghu (Pescadore) Islands, one region each year respectively. All fish specimens collected from trawling were brought back to lab for identification, individual number count and body weight measurement. These raw data have been integrated and established in Taiwan Fish Database (http://fishdb.sinica.edu.tw). They have also been published through TaiBIF (http://taibif.tw), FishBase and GBIF (website see below). This dataset contains 631 fish species and 3,529 records, making it the most complete demersal fish fauna and their temporal and spatial distributional data on the soft marine habitat in Taiwan. PMID:22707908

  2. A dataset from bottom trawl survey around Taiwan.

    PubMed

    Shao, Kwang-Tsao; Lin, Jack; Wu, Chung-Han; Yeh, Hsin-Ming; Cheng, Tun-Yuan

    2012-01-01

    Bottom trawl fishery is one of the most important coastal fisheries in Taiwan both in production and economic values. However, its annual production started to decline due to overfishing since the 1980s. Its bycatch problem also damages the fishery resource seriously. Thus, the government banned the bottom fishery within 3 nautical miles along the shoreline in 1989. To evaluate the effectiveness of this policy, a four year survey was conducted from 2000-2003, in the waters around Taiwan and Penghu (Pescadore) Islands, one region each year respectively. All fish specimens collected from trawling were brought back to lab for identification, individual number count and body weight measurement. These raw data have been integrated and established in Taiwan Fish Database (http://fishdb.sinica.edu.tw). They have also been published through TaiBIF (http://taibif.tw), FishBase and GBIF (website see below). This dataset contains 631 fish species and 3,529 records, making it the most complete demersal fish fauna and their temporal and spatial distributional data on the soft marine habitat in Taiwan.

  3. Vertical distribution of fish biomass in Lake Superior: Implications for day bottom trawl surveys

    USGS Publications Warehouse

    Stockwell, J.D.; Yule, D.L.; Hrabik, T.R.; Adams, J.V.; Gorman, O.T.; Holbrook, B.V.

    2007-01-01

    Evaluation of the biases in sampling methodology is essential for understanding the limitations of abundance and biomass estimates of fish populations. Estimates from surveys that rely solely on bottom trawls may be particularly vulnerable to bias if pelagic fish are numerous. We evaluated the variability in the vertical distribution of fish biomass during the U.S. Geological Survey's annual spring bottom trawl survey of Lake Superior using concurrent hydroacoustic observations to (1) test the assumption that fish are generally demersal during the day and (2) evaluate the potential for predictive models to improve bottom trawl–determined biomass estimates. Our results indicate that the assumption that fish exhibit demersal behavior during the annual spring bottom trawl survey in Lake Superior is unfounded. Bottom trawl biomass (BBT) estimates (mean ± SE) for species known to exhibit pelagic behavior (cisco Coregonus artedi, bloater C. hoyi, kiyi C. kiyi, and rainbow smelt Osmerus mordax; 3.01 ± 0.73 kg/ha) were not significantly greater than mean acoustic pelagic zone biomass (BAPZ) estimates (6.39 ± 2.03 kg/ha). Mean BAPZ estimates were 1.6- to 4.8-fold greater than mean BBT estimates over 4 years of sampling. The relationship between concurrent BAPZ and BBT estimates was marginally significant and highly variable. Predicted BAPZ estimates using cross-validation models were sensitive to adjustments for back-transforming from the logarithmic to the linear scale and poorly corresponded to observed BAPZ estimates. We conclude that statistical models to predict BAPZ from day BBT cannot be developed. We propose that night sampling with multiple gears will be necessary to generate better biomass estimates for management needs.

  4. Retrospective analysis of Bering Sea bottom trawl surveys: regime shift and ecosystem reorganization

    NASA Astrophysics Data System (ADS)

    Conners, M. E.; Hollowed, A. B.; Brown, E.

    2002-10-01

    This paper compiles data from bottom trawl surveys using variations on a 400-mesh eastern trawl gear into a 38-year time series (1963-2000), using a robust index of median catch per unit effort (CPUE) as an indicator of regional abundance. Time series are presented for three index sites in the southeastern Bering Sea: the inner shelf in Bristol Bay, the middle shelf north of Unimak Island, and the outer shelf near the Pribilof Islands. All three sites show strong evidence of a shift in benthic biomass and community structure in the early to mid-1980s. During this period, all three sites showed substantial increases in the abundances of walleye pollock, Pacific cod, rock sole, flathead sole, cartilaginous fishes (skates) and non-crab benthic invertebrates. Species composition, especially of flatfish, differs at the three sites, but the trend for groundfish abundance to increase was consistent at all three sites. The similarity in trends both across the region and across both commercial and unexploited groups suggests to us that a complete reorganization of benthic and demersal food webs may have taken place. The timing of change in trawl catch weight is consistent with effects of the strong regime shift observed in climate indices in 1976-1977. There is little evidence of similar biological responses to subsequent, less pronounced changes in climate. Our data are also consistent with recently documented shifts in ecosystem dynamics resulting from changes in ice cover and thermal structure in the eastern Bering Sea. Our analysis indicates that there was a much higher biomass of groundfish at all three sites during 1980-2000 than in 1960-1980. This result provides evidence against the hypothesis that the overall productivity of the eastern Bering Sea has decreased. The precipitous decline of the endangered Steller sea lion in this region from 1975-1985 was concurrent with an overall increase in abundance of groundfish prey.

  5. 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.

  6. 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

  7. Bottom-trawling along submarine canyons impacts deep sedimentary regimes

    NASA Astrophysics Data System (ADS)

    Paradis, Sarah; Puig, Pere; Masqué, Pere; Juan-Díaz, Xènia; Martín, Jacobo; Palanques, Albert

    2017-02-01

    Many studies highlight that fish trawling activities cause seafloor erosion, but the assessment of the remobilization of surface sediments and its relocation is still not well documented. These impacts were examined along the flanks and axes of three headless submarine canyons incised on the Barcelona continental margin, where trawling fleets have been operating for decades. Trawled grounds along canyon flanks presented eroded and highly reworked surface sediments resulting from the passage of heavy trawling gear. Sedimentation rates on the upper canyon axes tripled and quadrupled its natural (i.e. pre-industrialization) values after a substantial increase in total horsepower of the operating trawling fleets between 1960 s and 1970 s. These impacts affected the upper canyon reaches next to fishing grounds, where sediment resuspended by trawling can be transported towards the canyon axes. This study highlights that bottom trawling has the capacity to alter natural sedimentary environments by promoting sediment-starved canyon flanks, and by enhancing sedimentation rates along the contiguous axes, independently of canyons’ morphology. Considering the global mechanisation and offshore expansion of bottom trawling fisheries since the mid-20th century, these sedimentary alterations may occur in many trawled canyons worldwide, with further ecological impacts on the trophic status of these non-resilient benthic communities.

  8. Bottom-trawling along submarine canyons impacts deep sedimentary regimes.

    PubMed

    Paradis, Sarah; Puig, Pere; Masqué, Pere; Juan-Díaz, Xènia; Martín, Jacobo; Palanques, Albert

    2017-02-24

    Many studies highlight that fish trawling activities cause seafloor erosion, but the assessment of the remobilization of surface sediments and its relocation is still not well documented. These impacts were examined along the flanks and axes of three headless submarine canyons incised on the Barcelona continental margin, where trawling fleets have been operating for decades. Trawled grounds along canyon flanks presented eroded and highly reworked surface sediments resulting from the passage of heavy trawling gear. Sedimentation rates on the upper canyon axes tripled and quadrupled its natural (i.e. pre-industrialization) values after a substantial increase in total horsepower of the operating trawling fleets between 1960 s and 1970 s. These impacts affected the upper canyon reaches next to fishing grounds, where sediment resuspended by trawling can be transported towards the canyon axes. This study highlights that bottom trawling has the capacity to alter natural sedimentary environments by promoting sediment-starved canyon flanks, and by enhancing sedimentation rates along the contiguous axes, independently of canyons' morphology. Considering the global mechanisation and offshore expansion of bottom trawling fisheries since the mid-20(th) century, these sedimentary alterations may occur in many trawled canyons worldwide, with further ecological impacts on the trophic status of these non-resilient benthic communities.

  9. Bottom-trawling along submarine canyons impacts deep sedimentary regimes

    PubMed Central

    Paradis, Sarah; Puig, Pere; Masqué, Pere; Juan-Díaz, Xènia; Martín, Jacobo; Palanques, Albert

    2017-01-01

    Many studies highlight that fish trawling activities cause seafloor erosion, but the assessment of the remobilization of surface sediments and its relocation is still not well documented. These impacts were examined along the flanks and axes of three headless submarine canyons incised on the Barcelona continental margin, where trawling fleets have been operating for decades. Trawled grounds along canyon flanks presented eroded and highly reworked surface sediments resulting from the passage of heavy trawling gear. Sedimentation rates on the upper canyon axes tripled and quadrupled its natural (i.e. pre-industrialization) values after a substantial increase in total horsepower of the operating trawling fleets between 1960 s and 1970 s. These impacts affected the upper canyon reaches next to fishing grounds, where sediment resuspended by trawling can be transported towards the canyon axes. This study highlights that bottom trawling has the capacity to alter natural sedimentary environments by promoting sediment-starved canyon flanks, and by enhancing sedimentation rates along the contiguous axes, independently of canyons’ morphology. Considering the global mechanisation and offshore expansion of bottom trawling fisheries since the mid-20th century, these sedimentary alterations may occur in many trawled canyons worldwide, with further ecological impacts on the trophic status of these non-resilient benthic communities. PMID:28233856

  10. Effects of bottom trawling on fish foraging and feeding

    PubMed Central

    Johnson, Andrew Frederick; Gorelli, Giulia; Jenkins, Stuart Rees; Hiddink, Jan Geert; Hinz, Hilmar

    2015-01-01

    The effects of bottom trawling on benthic invertebrates include reductions of biomass, diversity and body size. These changes may negatively affect prey availability for demersal fishes, potentially leading to reduced food intake, body condition and yield of fishes in chronically trawled areas. Here, the effect of trawling on the prey availability and diet of two commercially important flatfish species, plaice (Pleuronectes platessa) and dab (Limanda limanda), was investigated over a trawling intensity gradient in the Irish Sea. Previous work in this area has shown that trawling negatively affects the condition of plaice but not of dab. This study showed that reductions in local prey availability did not result in reduced feeding of fish. As trawling frequency increased, both fish and prey biomass declined, such that the ratio of fish to prey remained unchanged. Consequently, even at frequently trawled sites with low prey biomass, both plaice and dab maintained constant levels of stomach fullness and gut energy contents. However, dietary shifts in plaice towards energy-poor prey items were evident when prey species were analysed individually. This, together with a potential decrease in foraging efficiency due to low prey densities, was seen as the most plausible cause for the reduced body condition observed. Understanding the relationship between trawling, benthic impacts, fish foraging and resultant body condition is an important step in designing successful mitigation measures for future management strategies in bottom trawl fisheries. PMID:25621336

  11. Assessing prey fish populations in Lake Michigan: Comparison of simultaneous acoustic-midwater trawling with bottom trawling

    USGS Publications Warehouse

    Fabrizio, Mary C.; Adams, Jean V.; Curtis, Gary L.

    1997-01-01

    The Lake Michigan fish community has been monitored since the 1960s with bottom trawls, and since the late 1980s with acoustics and midwater trawls. These sampling tools are limited to different habitats: bottom trawls sample fish near bottom in areas with smooth substrates, and acoustic methods sample fish throughout the water column above all substrate types. We compared estimates of fish densities and species richness from daytime bottom trawling with those estimated from night-time acoustic and midwater trawling at a range of depths in northeastern Lake Michigan in summer 1995. We examined estimates of total fish density as well as densities of alewife Alosa pseudoharengus (Wilson), bloater Coregonus hoyi (Gill), and rainbow smelt Osmerus mordax (Mitchell) because these three species are the dominant forage of large piscivores in Lake Michigan. In shallow water (18 m), we detected more species but fewer fish (in fish/ha and kg/ha) with bottom trawls than with acoustic-midwater trawling. Large aggregations of rainbow smelt were detected by acoustic-midwater trawling at 18 m and contributed to the differences in total fish density estimates between gears at this depth. Numerical and biomass densitites of bloaters from all depths were significantly higher when based on bottom trawl samples than on acoustic-midwater trawling, and this probably contributed to the observed significant difference between methods for total fish densities (kg/ha) at 55 m. Significantly fewer alewives per ha were estimated from bottom trawling than from acoustics-midwater trawling at 55 m, and in deeper waters, no alewives were taken by bottom trawling. The differences detected between gears resulted from alewife, bloater, and rainbow smelt vertical distributions, which varied with lake depth and time of day. Because Lake Michigan fishes are both demersal and pelagic, a single sampling method cannot be used to completely describe characteristics of the fish community.

  12. Evaluation of bottom trawls as compared to acoustics to assess adult Lake Herring (Coregonus artedi) abundance in Lake Superior

    USGS Publications Warehouse

    Stockwell, J.D.; Yule, D.L.; Gorman, O.T.; Isaac, E.J.; Moore, S.A.

    2006-01-01

    We compared density estimates from day bottom trawl tows against night midwater trawl tows and acoustic gear to test the hypothesis that adult lake herring (≥250 mm) are underestimated by day bottom trawl tows during the annual USGS spring fish community survey in Lake Superior. We found average density at nine nearshore stations was significantly higher at night (21.3 adult fish/ha) compared to day (1.0 adult fish/ha; p = 0.0119). At nine offshore stations, no lake herring were captured during the day but density averaged 39.6 adult fish/ha at night. At a lakewide scale (n = 18 stations), precision (relative standard error) was much better using night midwater trawls and acoustic gear (37%) compared to day bottom trawls (100%). Moderate sample size increases using the former methodology would likely bring precision within recommended levels (≤30%) for stock-recruit data sets. Our results suggest that 1) population abundances of adult lake herring in Lake Superior are much higher than previously considered, 2) the annual spring fish community survey may not provide a relative index of abundance of adult lake herring, 3) night midwater trawls and acoustic gear are necessary for assessing adult lake herring abundance, and 4) previous studies using lake herring data from the annual spring fish community survey need to be re-evaluated in light of these results. Lake herring appear to become progressively more pelagic and less susceptible to bottom trawling as they mature. Day bottom trawls appear to be an adequate tool for estimating relative density of age-1 recruits, although this method still suffers from relatively poor precision.

  13. Evaluation of Midwater Trawl Selectivity and its Influence on Acoustic-Based Fish Population Surveys

    NASA Astrophysics Data System (ADS)

    Williams, Kresimir

    Trawls are used extensively during fisheries abundance surveys to derive estimates of fish density and, in the case of acoustic-based surveys, to identify acoustically sampled fish populations. However, trawls are selective in what fish they retain, resulting in biased estimates of density, species, and size compositions. Selectivity of the midwater trawl used in acoustic-based surveys of walleye pollock (Theragra chalcogramma) was evaluated using multiple methods. The effects of trawl selectivity on the acoustic-based survey abundance estimates and the stock assessment were evaluated for the Gulf of Alaska walleye pollock population. Selectivity was quantified using recapture, or pocket, nets attached to the outside of the trawl. Pocket net catches were modeled using a hierarchical Bayesian model to provide uncertainty in selectivity parameter estimates. Significant under-sampling of juvenile pollock by the midwater trawl was found, with lengths at 50% retention ranging from 14--26 cm over three experiments. Escapement was found to be light dependent, with more fish escaping in dark conditions. Highest escapement rates were observed in the aft of the trawl near to the codend though the bottom panel of the trawl. The behavioral mechanisms involved in the process of herding and escapement were evaluated using stereo-cameras, a DIDSON high frequency imaging sonar, and pocket nets. Fish maintained greater distances from the trawl panel during daylight, suggesting trawl modifications such as increased visibility of netting materials may evoke stronger herding responses and increased retention of fish. Selectivity and catchability of pollock by the midwater trawl was also investigated using acoustic density as an independent estimate of fish abundance to compare with trawl catches. A modeling framework was developed to evaluate potential explanatory factors for selectivity and catchability. Selectivity estimates were dependent on which vessel was used for the survey

  14. What a drag: Quantifying the global impact of chronic bottom trawling on continental shelf sediment

    USGS Publications Warehouse

    Oberle, Ferdinand K.J.; Storlazzi, Curt; Hanebuth, Till J.J.

    2016-01-01

    Continental shelves worldwide are subject to intense bottom trawling that causes sediment to be resuspended. The widely used traditional concepts of modern sedimentary transport systems on the shelf rely only on estimates for naturally driven sediment resuspension such as through storm waves, bottom currents, and gravity-driven flows but they overlook a critical anthropogenic factor. The strong influence of bottom trawling on a source-to-sink sediment budget is explored on the NW Iberian shelf. Use of Automated Information System vessel tracking data provides for a high-resolution vessel track reconstruction and the accurate calculation of the spatial distribution of bottom trawling intensity and associated resuspended sediment load. The mean bottom trawling-induced resuspended sediment mass for the NW Iberian shelf is 13.50 Mt yr− 1, which leads to a six-fold increase in off-shelf sediment transport when compared to natural resuspension mechanisms. The source-to-sink budget analysis provides evidence that bottom trawling causes a rapid erosion of the fine sediment on human time scales. Combining global soft sediment distribution data of the shelves with worldwide bottom trawling intensity estimates we show that the bottom trawling-induced resuspended sediment mass amounts to approximately the same mass of all sediment entering the shelves through rivers. Spatial delineations between natural and anthropogenic sediment resuspension areas are presented to aid in marine management questions.

  15. What a drag: Quantifying the global impact of chronic bottom trawling on continental shelf sediment

    NASA Astrophysics Data System (ADS)

    Oberle, Ferdinand K. J.; Storlazzi, Curt D.; Hanebuth, Till J. J.

    2016-07-01

    Continental shelves worldwide are subject to intense bottom trawling that causes sediment to be resuspended. The widely used traditional concepts of modern sedimentary transport systems on the shelf rely only on estimates for naturally driven sediment resuspension such as through storm waves, bottom currents, and gravity-driven flows but they overlook a critical anthropogenic factor. The strong influence of bottom trawling on a source-to-sink sediment budget is explored on the NW Iberian shelf. Use of Automated Information System vessel tracking data provides for a high-resolution vessel track reconstruction and the accurate calculation of the spatial distribution of bottom trawling intensity and associated resuspended sediment load. The mean bottom trawling-induced resuspended sediment mass for the NW Iberian shelf is 13.50 Mt yr- 1, which leads to a six-fold increase in off-shelf sediment transport when compared to natural resuspension mechanisms. The source-to-sink budget analysis provides evidence that bottom trawling causes a rapid erosion of the fine sediment on human time scales. Combining global soft sediment distribution data of the shelves with worldwide bottom trawling intensity estimates we show that the bottom trawling-induced resuspended sediment mass amounts to approximately the same mass of all sediment entering the shelves through rivers. Spatial delineations between natural and anthropogenic sediment resuspension areas are presented to aid in marine management questions.

  16. Satellite-based quantification of the bottom trawling induced sediment resuspension over an entire shelf

    NASA Astrophysics Data System (ADS)

    Oberle, F. J.; Cheriton, O. M.; Hanebuth, T. J. J.

    2014-12-01

    The effect of bottom trawling activities on continental shelves has been a topic of interest for both fishery resource studies and ecological impact studies for a while. However, the impact of demersal fishing gear was almost exclusively studied from a perspective of its effects on benthic fauna, but recently it has also attracted attention due to its profound impact on sediments. Here we present the first study to quantify the trawling-induced sediment resuspension effect by combining satellite-based spatial patterns of bottom trawling with quantitative measurements of induced sediment plumes. This study examined high-resolution GPS vessel monitoring data from one year (2011-2012) to quantify the sedimentary budget caused by bottom trawling activity for the entire NW Iberian shelf, an area that is widely affected by chronic (continuous and intensive) commercial bottom trawling and is exemplary for many other narrow shelves worldwide. By filtering the GPS data by vessel type, vessel speed, and geometry of the trawl path, we resolved geographically detailed bottom trawling activities with varying local trawling intensities depending both on legal restrictions and bedrock geomorphology. Initial results show that trawling-induced resuspended sediments mark a significant if not dominant factor for a source to sink sedimentary budget, as they are calculated to be approximately two times as large as fluvial sedimentary input to the shelf. Ultimately, these results not only allow for a trawling affected sediment budget but also significantly help with marine management decisions by allowing to predict the mobilization and transport of sediment caused by bottom trawling gear at the level of a specific fishing fleet or ecosystem.

  17. Effects of bottom trawling on the Ebro continental shelf sedimentary system (NW Mediterranean)

    NASA Astrophysics Data System (ADS)

    Palanques, Albert; Puig, Pere; Guillén, Jorge; Demestre, Montserrat; Martín, Jacobo

    2014-01-01

    A monitoring effort to address the physical effects of bottom trawling was conducted on the Ebro prodeltaic mud belt during the RESPONSE project. The monitoring was carried out for 14 months covering periods of different trawling intensities and a close season for the trawling fleet. The seabed morphology was studied by side-scan sonar and sediment texture and organic carbon content were analysed. Suspended sediment vertical distribution was recorded by CTD+turbidity hydrographic profiles and sediment transport was computed using time series from moored turbidimeters and current meters. The results show that the seabed of the fishing ground is strongly affected by scraping and ploughing induced by bottom trawling. Part of the finer fraction of the prodeltaic mud resuspended by trawling is winnowed, increasing the silt content of the settling sediment and also near-bottom turbidity. Sediment resuspended by trawling is incorporated in the bottom nepheloid layer and transported across- and along-shelf, increasing sediment fluxes. Trawling also induces an increase in the organic carbon content in the bottom sediment. All these effects induced by trawling have occurred during the last few decades, changing natural conditions in the fishing ground.

  18. Distribution of Bottom Trawling Effort in the Yellow Sea and East China Sea

    PubMed Central

    Zhang, Shengmao; Jin, Shaofei; Zhang, Heng; Fan, Wei; Tang, Fenghua; Yang, Shenglong

    2016-01-01

    Bottom trawling is one of the most efficient fishing activities, but serious and persistent ecological issues have been observed by fishers, scientists and fishery managers. Although China has applied the Beidou fishing vessel position monitoring system (VMS) to manage trawlers since 2006, little is known regarding the impacts of trawling on the sea bottom environments. In this study, continuous VMS data of the 1403 single-rig otter trawlers registered in the Xiangshan Port, 3.9% of the total trawlers in China, were used to map the trawling effort in 2013. We used the accumulated distance (AD), accumulated power distance (APD), and trawling intensity as indexes to express the trawling efforts in the Yellow Sea (YS) and East China Sea (ECS). Our results show that all three indexes had similar patterns in the YS and ECS, and indicated a higher fishing effort of fishing grounds that were near the port. On average, the seabed was trawled 0.73 times in 2013 over the entire fishing region, and 51.38% of the total fishing grounds were with no fishing activities. Because of VMS data from only a small proportion of Chinese trawlers was calculated fishing intensity, more VMS data is required to illustrate the overall trawling effort in China seas. Our results enable fishery managers to identify the distribution of bottom trawling activities in the YS and ECS, and hence to make effective fishery policy. PMID:27855215

  19. Distribution of Bottom Trawling Effort in the Yellow Sea and East China Sea.

    PubMed

    Zhang, Shengmao; Jin, Shaofei; Zhang, Heng; Fan, Wei; Tang, Fenghua; Yang, Shenglong

    2016-01-01

    Bottom trawling is one of the most efficient fishing activities, but serious and persistent ecological issues have been observed by fishers, scientists and fishery managers. Although China has applied the Beidou fishing vessel position monitoring system (VMS) to manage trawlers since 2006, little is known regarding the impacts of trawling on the sea bottom environments. In this study, continuous VMS data of the 1403 single-rig otter trawlers registered in the Xiangshan Port, 3.9% of the total trawlers in China, were used to map the trawling effort in 2013. We used the accumulated distance (AD), accumulated power distance (APD), and trawling intensity as indexes to express the trawling efforts in the Yellow Sea (YS) and East China Sea (ECS). Our results show that all three indexes had similar patterns in the YS and ECS, and indicated a higher fishing effort of fishing grounds that were near the port. On average, the seabed was trawled 0.73 times in 2013 over the entire fishing region, and 51.38% of the total fishing grounds were with no fishing activities. Because of VMS data from only a small proportion of Chinese trawlers was calculated fishing intensity, more VMS data is required to illustrate the overall trawling effort in China seas. Our results enable fishery managers to identify the distribution of bottom trawling activities in the YS and ECS, and hence to make effective fishery policy.

  20. Trophic look at soft-bottom communities - Short-term effects of trawling cessation on benthos

    NASA Astrophysics Data System (ADS)

    Dannheim, Jennifer; Brey, Thomas; Schröder, Alexander; Mintenbeck, Katja; Knust, Rainer; Arntz, Wolf E.

    2014-01-01

    The trophic structure of the German Bight soft-bottom benthic community was evaluated for potential changes after cessation of bottom trawling. Species were collected with van-Veen grabs and beam trawls. Trophic position (i.e. nitrogen stable isotope ratios, δ15N) and energy flow (i.e. species metabolism approximated by body mass scaled abundance) of dominant species were compared in trawled areas and an area protected from fisheries for 14 months in order to detect trawling cessation effects by trophic characteristics. At the community level, energy flow was lower in the protected area, but we were unable to detect significant changes in trophic position. At the species level energy flow in the protected area was lower for predating/scavenging species but higher for interface feeders. Species trophic positions of small predators/scavengers were lower and of deposit feeders higher in the protected area. Major reasons for trophic changes after trawling cessation may be the absence of artificial and additional food sources from trawling likely to attract predators and scavengers, and the absence of physical sediment disturbance impacting settlement/survival of less mobile species and causing a gradual shift in food availability and quality. Our results provide evidence that species or community energy flow is a good indicator to detect trawling induced energy-flow alterations in the benthic system, and that in particular species trophic properties are suitable to capture subtle and short-term changes in the benthos following trawling cessation.

  1. Bottom trawling and oxygen minimum zone influences on continental slope benthic community structure off Vancouver Island (NE Pacific)

    NASA Astrophysics Data System (ADS)

    De Leo, Fabio C.; Gauthier, Maéva; Nephin, Jessica; Mihály, Steven; Juniper, S. Kim

    2017-03-01

    Understanding responses of benthic ecosystems to cumulative impacts of natural stressors, long-term ocean change and increasing resource exploitation is an emerging area of interest for marine ecologists and environmental managers. Few, if any, studies have quantitatively addressed cumulative effects in the deep sea. We report here on a study from the continental slope off Vancouver Island (Canada) in the northeast Pacific Ocean, where the Oxygen Minimum Zone impinges on seabed habitats that are subjected to widespread bottom trawling, primarily by the fishery for thornyhead (Sebastolobus ssp.). We examined how the benthic megafauna in this area was influenced by varying levels of dissolved oxygen and trawling activity, along a depth gradient that was also likely to shape community composition. Continuous video and sonar records from two ROV surveys (50 linear km total; depth range 300-1400 m) respectively provided data on faunal attributes (composition, abundance and diversity) and the frequency of trawl door marks on the seabed. Faunal and trawl data were compiled in a geo-referenced database along with corresponding dissolved oxygen data, and pooled into 500 m segments for statistical analysis. Trawl mark occurrence peaked between 500 and 1100 m, corresponding to areas of slope subjected to hypoxia (<1.4 ml l-1) and severe hypoxia (<0.5 ml l-1). A combined total of 266,251 megafauna organisms from 87 taxa were enumerated in the two transects. Significant megafaunal assemblages according to depth, trawling intensity and bottom water dissolved oxygen concentration were identified by PERMANOVA analyses, with characterizing taxa identified for all three factors. Depth, dissolved oxygen and trawl mark density accounted for 21% to 52% of the variability in benthic community structure according to multiple regression (DISTLM) models. Species richness was highest at intermediate depths and in areas subject to intermediate levels of trawling, and higher under hypoxia

  2. A comparison between benthic gillnet and bottom trawl for assessing fish assemblages in a shallow eutrophic lake near the Changjiang River estuary

    NASA Astrophysics Data System (ADS)

    Li, Yalei; Liu, Qigen; Chen, Liping; Zhao, Liangjie; Wu, Hao; Chen, Liqiao; Hu, Zhongjun

    2017-06-01

    Two fishing methods including gillnetting and trawling to estimate attributes of fish assemblage were compared in Dianshan Lake from August 2009 to July 2010. Species composition differed significantly between the gears, with four significant contributors in gillnet catches and one in trawl catches. Trawling collected more proportions of benthic species by number and biomass than gillnetting. Size distribution was significantly influenced by fishing technique; gillnetting captured relatively less small-sized fishes and trawling captured less large-sized individuals. Trawling produced species richness closer to the one expected than gillnetting. On the whole, trawl catch was a quadratic polynomial function of gillnet catch and a significantly negative correlation was found between them, both of which varied as different polynomial functions of temperature. However, trawl and gillnet catches were significantly correlated only in one of five month groups. It is concluded that single-gear-based surveys can be misleading in assessments of attributes of fish assemblages, bottom trawling is a more effective gear for assessing fish diversity than benthic gillnetting, and using gillnet catches as an indicator of fish density depends on fishing season in the lake.

  3. Deciphering the lithological consequences of bottom trawling to sedimentary habitats on the shelf

    NASA Astrophysics Data System (ADS)

    Oberle, Ferdinand K. J.; Swarzenski, Peter W.; Reddy, Christopher M.; Nelson, Robert K.; Baasch, Benjamin; Hanebuth, Till J. J.

    2016-07-01

    Widespread bottom trawling on the NW Iberian shelf causes chronic sediment and habitat disturbance. The few studies that have investigated vessel-modified sedimentary-structure and texture of the seabed have typically classified their results as being either impacted by trawling or not. This study indicates that bottom trawling can result in a sequence of vastly different effects to the lithology of seabed sediment, which have in turn different ecological consequences. Here, we combined very high-resolution spatial bottom-trawling data with sedimentological (grain size, porosity) and geochemical datasets (excess 210Pb, 3D petroleum fingerprinting) to study sediment disturbance, including sorting and mixing. Our results were used to develop five conceptual disturbance scenarios: minimal seabed effects, sediment overturning, complete sediment mixing, sediment grading and layering, and loss of sediment. Considering that bottom trawling is a widespread and growing global fishing technique, such impacts need to be considered in the management of habitat conservation as well as in the reconstruction of late Holocene climate history from shallow-water deposits, not just on the NW Iberian shelf, but also globally.

  4. Lake Ontario Deepwater Sculpin bottom trawl catch and biological data, 1996-2016

    USGS Publications Warehouse

    Weidel, Brian C.

    2016-01-01

    Deepwater Sculpin are important in oligotrophic lakes as one of the few fishes that use deep profundal habitats and link invertebrates in those habitats to piscivores. In Lake Ontario the species was once abundant, however drastic declines in the mid-1900s led some to suggest the species had been extirpated and ultimately led Canadian and U.S. agencies to elevate the species’ conservation status in the 1990s. Following multiple decades of annual surveys with no captures, Deepwater Sculpin were first caught in low numbers in 1996 and by the early 2000s there were indications of population recovery. These data sets were used to update the status of Lake Ontario Deepwater Sculpin through 2016 to inform resource management and conservation. The entire data set includes tables for bottom trawl catches, length frequency, individual fish length weight, as well as gonad weight.

  5. Global analysis of depletion and recovery of seabed biota after bottom trawling disturbance

    PubMed Central

    Hiddink, Jan Geert; Jennings, Simon; Sciberras, Marija; Szostek, Claire L.; Hughes, Kathryn M.; Ellis, Nick; Rijnsdorp, Adriaan D.; McConnaughey, Robert A.; Mazor, Tessa; Hilborn, Ray; Collie, Jeremy S.; Pitcher, C. Roland; Amoroso, Ricardo O.; Parma, Ana M.; Suuronen, Petri; Kaiser, Michel J.

    2017-01-01

    Bottom trawling is the most widespread human activity affecting seabed habitats. Here, we collate all available data for experimental and comparative studies of trawling impacts on whole communities of seabed macroinvertebrates on sedimentary habitats and develop widely applicable methods to estimate depletion and recovery rates of biota after trawling. Depletion of biota and trawl penetration into the seabed are highly correlated. Otter trawls caused the least depletion, removing 6% of biota per pass and penetrating the seabed on average down to 2.4 cm, whereas hydraulic dredges caused the most depletion, removing 41% of biota and penetrating the seabed on average 16.1 cm. Median recovery times posttrawling (from 50 to 95% of unimpacted biomass) ranged between 1.9 and 6.4 y. By accounting for the effects of penetration depth, environmental variation, and uncertainty, the models explained much of the variability of depletion and recovery estimates from single studies. Coupled with large-scale, high-resolution maps of trawling frequency and habitat, our estimates of depletion and recovery rates enable the assessment of trawling impacts on unprecedented spatial scales. PMID:28716926

  6. Commercial bottom trawling: a driver of deep seascape evolution in the Anthropocene?

    NASA Astrophysics Data System (ADS)

    Martín, Jacobo; Puig, Pere; Canals, Miquel; Company, Joan B.; Amblas, David; Lastras, Galderic; Palanques, Albert; Calafat, Antoni M.

    2013-04-01

    The offshore displacement of bottom trawling fleets has raised concerns over the impact of this human activity on deep-sea ecosystems and associated living resources, which are characterized by a lower resilience than shallow water correlatives. However, the effects of bottom trawling on sediment remobilization across continental margins and on the alteration of seafloor morphology still remain largely unaddressed. We present a compilation of results from studies conducted during the last decade in the La Fonera (Palamós) submarine canyon (NW Mediterranean Sea), where a bottom trawling fishing fleet is active on a daily basis at depths from 400 to 800 m. Deployments of mooring lines equipped with punctual and profiling current-meters, turbidimeters and sediment traps have documented that trawling gears passing along the canyon flanks generate daily sediment gravity flows, implying a periodic sediment removal from fishing grounds. These sediment-laden flows are able to reach the main canyon axis and progress to a minimum depth of 1200 m. Also, sediment accumulation rates in the lower canyon have increased since the industrialization of the local trawling fleet (1970s), suggesting a human-induced enhancement of along-canyon transfer of sediments from the fishing grounds to greater depths. Sedimentological and Pb-210 analysis of interface sediment cores collected from the canyon flanks confirm that widespread erosion and stirring of surface sediments is notable on trawled areas when compared to control (untrawled) sites at similar depths. This chronic reworking and removal of surface sediments from trawling grounds has ultimately led to modifications of the seafloor morphology over large spatial scales, as revealed by high-resolution multibeam bathymetry and Vessel Monitoring Systems (VMS) data sets. Untrawled canyon flank segments are dominated by a dense network of tributary valleys that progress upslope from the main canyon axis, reaching up to five orders of

  7. Chronic and intensive bottom trawling impairs deep-sea biodiversity and ecosystem functioning

    PubMed Central

    Pusceddu, Antonio; Bianchelli, Silvia; Martín, Jacobo; Puig, Pere; Palanques, Albert; Masqué, Pere; Danovaro, Roberto

    2014-01-01

    Bottom trawling has many impacts on marine ecosystems, including seafood stock impoverishment, benthos mortality, and sediment resuspension. Historical records of this fishing practice date back to the mid-1300s. Trawling became a widespread practice in the late 19th century, and it is now progressively expanding to greater depths, with the concerns about its sustainability that emerged during the first half of the 20th century now increasing. We show here that compared with untrawled areas, chronically trawled sediments along the continental slope of the north-western Mediterranean Sea are characterized by significant decreases in organic matter content (up to 52%), slower organic carbon turnover (ca. 37%), and reduced meiofauna abundance (80%), biodiversity (50%), and nematode species richness (25%). We estimate that the organic carbon removed daily by trawling in the region under scrutiny represents as much as 60–100% of the input flux. We anticipate that such an impact is causing the degradation of deep-sea sedimentary habitats and an infaunal depauperation. With deep-sea trawling currently conducted along most continental margins, we conclude that trawling represents a major threat to the deep seafloor ecosystem at the global scale. PMID:24843122

  8. Latitudinal trends and temporal shifts in the catch composition of bottom trawls conducted on the eastern Bering Sea shelf

    NASA Astrophysics Data System (ADS)

    Stevenson, Duane E.; Lauth, Robert R.

    2012-06-01

    Latitudinal species diversity gradients are well known in both terrestrial and aquatic ecosystems throughout the world. However, trends in relative abundance and other shifts in community structure with latitude, which can be more sensitive to environmental shifts such as climate change, have received less attention. Here we investigate latitudinal trends in the seafloor community of the eastern Bering Sea using catches of fishes and epibenthic invertebrates in bottom trawl surveys conducted from 1982 to 2010. Our results indicate that the overall biomass of the epibenthic community declines with increasing latitude in the eastern Bering Sea. This latitudinal trend is primarily driven by declining fish catches in the northern Bering Sea, which in turn reflects changes in the structure of the fish community. The fish fauna in northern latitudes is increasingly dominated by gadids, though the species composition of the gadid fauna also changes with latitude, with smaller species becoming more common in the north. The biomass of the invertebrate megafauna remains relatively consistent throughout the eastern Bering Sea, but invertebrates make up a larger proportion of the catch in bottom trawls conducted at higher latitudes. The epibenthic invertebrate megafauna in the eastern Bering Sea is composed primarily of sea stars (Asteriidae) and oregoniid crabs (Chionoecetes and Hyas), though no clear latitudinal trends in the invertebrate community are evident. Limited trawl data from the eastern Chukchi Sea indicate that the fish community farther north is even more heavily dominated by gadids, and the epibenthic invertebrate community is dominated by asteriid sea stars. Temperature data from bottom trawl surveys in the southeastern Bering Sea over the past decade indicate that there was a distinct temperature shift around 2005, and the relatively warm years of 2001-2005 were followed by five relatively cold years. This shift in the summer temperature regime of the Bering

  9. Marine litter in bottom trawls off the Portuguese coast.

    PubMed

    Neves, Diogo; Sobral, Paula; Pereira, Tânia

    2015-10-15

    Benthic marine litter along the Portuguese coast, was recorded in 14 trips on stern trawlers covering a distance of 2117 km and an area of 56.2 km(2), average depth range 90-349 m. 2034 items of marine litter were registered, 76% were plastics and 38.6% were originated from fishing related activities. Plastic was present in all the trawls and had the highest average density of all litter categories, 50 items km(-2). The highest density of marine litter (178.9 ± 64.0 items km(-2)) was found in the proximity of the Tagus river mouth, probably related to the high population density in the Lisbon metropolitan area. This study highlights the need to raise fishermen awareness for the adoption of good environmental practices that will contribute to the reduction of marine litter.

  10. Using marine reserves to manage impact of bottom trawl fisheries requires consideration of benthic food-web interactions.

    PubMed

    van Denderen, P Daniël; Rijnsdorp, Adriaan D; van Kooten, Tobias

    2016-10-01

    Marine protected areas (MPAs) are widely used to protect exploited fish species as well as to conserve marine habitats and their biodiversity. They have also become a popular management tool for bottom trawl fisheries, a common fishing technique on continental shelves worldwide. The effects of bottom trawling go far beyond the impact on target species, as trawls also affect other components of the benthic ecosystem and the seabed itself. This means that for bottom trawl fisheries, MPAs can potentially be used not only to conserve target species but also to reduce impact of these side effects of the fishery. However, predicting the protective effects of MPAs is complicated because the side effects of trawling potentially alter the food-web interactions between target and non-target species. These changes in predatory and competitive interactions among fish and benthic invertebrates may have important ramifications for MPAs as tools to manage or mitigate the effects of bottom trawling. Yet, in current theory regarding the functioning of MPAs in relation to bottom trawl fisheries, such predatory and competitive interactions between species are generally not taken into account. In this study, we discuss how food-web interactions that are potentially affected by bottom trawling may alter the effectiveness of MPAs to protect (1) biodiversity and marine habitats, (2) fish populations, (3) fisheries yield, and (4) trophic structure of the community. We make the case that in order to be applicable for bottom trawl fisheries, guidelines for the implementation of MPAs must consider their potential food-web effects, at the risk of failing management.

  11. Visual surveys can reveal rather different 'pictures' of fish densities: Comparison of trawl and video camera surveys in the Rockall Bank, NE Atlantic Ocean

    NASA Astrophysics Data System (ADS)

    McIntyre, F. D.; Neat, F.; Collie, N.; Stewart, M.; Fernandes, P. G.

    2015-01-01

    Visual surveys allow non-invasive sampling of organisms in the marine environment which is of particular importance in deep-sea habitats that are vulnerable to damage caused by destructive sampling devices such as bottom trawls. To enable visual surveying at depths greater than 200 m we used a deep towed video camera system, to survey large areas around the Rockall Bank in the North East Atlantic. The area of seabed sampled was similar to that sampled by a bottom trawl, enabling samples from the towed video camera system to be compared with trawl sampling to quantitatively assess the numerical density of deep-water fish populations. The two survey methods provided different results for certain fish taxa and comparable results for others. Fish that exhibited a detectable avoidance behaviour to the towed video camera system, such as the Chimaeridae, resulted in mean density estimates that were significantly lower (121 fish/km2) than those determined by trawl sampling (839 fish/km2). On the other hand, skates and rays showed no reaction to the lights in the towed body of the camera system, and mean density estimates of these were an order of magnitude higher (64 fish/km2) than the trawl (5 fish/km2). This is probably because these fish can pass under the footrope of the trawl due to their flat body shape lying close to the seabed but are easily detected by the benign towed video camera system. For other species, such as Molva sp, estimates of mean density were comparable between the two survey methods (towed camera, 62 fish/km2; trawl, 73 fish/km2). The towed video camera system presented here can be used as an alternative benign method for providing indices of abundance for species such as ling in areas closed to trawling, or for those fish that are poorly monitored by trawl surveying in any area, such as the skates and rays.

  12. Hydrodynamic characteristics of the oval cambered double slotted otter board in bottom trawl fisheries

    NASA Astrophysics Data System (ADS)

    Liu, J.; Huang, H. L.; Li, L. Z.; Qu, T. C.; Wu, Y.; Chen, S.; Yang, J. L.; Rao, X.

    2017-07-01

    The otter board is one of the main components of single boat trawl fisheries. An oval cambered double slotted otter board was developed for improving the expansion performance of trawl net in bottom trawl fisheries. A flume model experiment was conducted to measure the lift coefficient (C L), drag coefficient (C D), and lift to drag ratio (K) in different angles of attack (α). The experimental results are as follows : (1) The C L and K value show a trend of increasing at the beginning and then decreasing with the increase of angle of attack, the C D value reflects an upward trend as the angle of attack increases; (2) The D3 otter board (front flow deflector angle at 29°) showed a better hydrodynamic performance. When α=30°, the max lift coefficient (C Lmax) was 1.464, in this case C D = 0.554 and K=2.643. When α=15°, the max lift to drag ratio (K max) was 4.165, C L =0.633, and C D = 0.152. This suggests that the best working scope for the angle of attack is between 15°~30°, in which case, C L>0.633 and K>2.643. The mean value of the lift coefficient was 1.071 and the mean of the lift to drag ratio was 3.482. Comparative analysis of the hydrodynamic performance of different types of otter boards showed that the D3 otter board both had good expansion performance and efficiency, which can provide a reference basis for further optimization of the bottom trawl otter board.

  13. Bottom trawl impacts on Mediterranean demersal fish diversity: Not so obvious or are we too late?

    NASA Astrophysics Data System (ADS)

    Farriols, M. Teresa; Ordines, Francesc; Somerfield, Paul J.; Pasqual, Catalina; Hidalgo, Manuel; Guijarro, Beatriz; Massutí, Enric

    2017-04-01

    Measures of biodiversity change may be useful as indicators if they are responsive to manageable drivers of biodiversity loss. However, there are many candidate indicators that are considered to be robust to survey artifacts and sensitive to manageable impacts. Using extensive survey data on demersal fish assemblages around the Balearic Islands (western Mediterranean) we analyze relationships among 'traditional', taxonomic and functional diversity indices, to identify a minimum set of indices that provide a good representation of the different aspects of diversity. Secondly we model the responses of the demersal fish community diversity to bottom trawl fishing pressure. To do so, we used two different approaches: (i) considering fishing effort and depth as continuous explanatory variables; and (ii) grouping samples according to bathymetric sampling strata and contrasting levels of fishing effort. The results show that diversity can be described using different complementary aspects such as species richness, evenness, and the taxonomic and functional breadth of the species present in a given community, displaying different responses to fishing pressure. However, the changes in diversity in response to fishing may only be detectable in those communities where the levels of fishing pressure have remained relatively low. When communities have been exposed to high levels of fishing pressure for a long period, the relevant changes in diversity may have happened long before the onset of monitoring of the fishery, and hence it may be too late to detect differences between levels of fishing effort. This seems to be the case on the middle slope of the Balearic Islands, where vulnerable species have disappeared or are very infrequent, and have been replaced by species better-adapted to fishing impacts.

  14. Spatial variability of soft-bottom macrobenthic communities in northern Sicily (Western Mediterranean): Contrasting trawled vs. untrawled areas.

    PubMed

    Romano, C; Fanelli, E; D'Anna, G; Pipitone, C; Vizzini, S; Mazzola, A; Badalamenti, F

    2016-12-01

    This study examines the impact of bottom trawl fishing on the macrobenthic communities inhabiting the coastal terrigenous mud off the northern coast of Sicily (Western Mediterranean). Two intensely trawled gulfs were compared with two gulfs from which trawling has been excluded for 15 years. The results show a significant effect of trawling on the faunal assemblage and when comparing the mean biomass and the whole isotopic composition of the benthic communities. A similar pattern, although not significant, was found for total abundance, biomass, production/biomass ratio and diversity. Higher abundance and lower biomass were found in the untrawled areas, attributable to the presence of more numerous yet smaller individuals, possibly a consequence of more abundant larger predators that are not removed by trawling, and consequent higher predatory pressure on the benthic macrofauna. The SIMPER analysis evidenced a dominance of burrowing deposit feeding worms (Paraonidae and Cossuridae) in trawled areas, as a result of increased mechanical alteration and hence more organic matter available as food. In contrast, the response to trawling as drawn by the use of trophic markers (i.e., stable isotopes) was less clear. While δ(15)N of benthic taxa did not vary significantly between untrawled and trawled areas, δ(13)C was higher in trawled areas possibly due to high sediment resuspension and consequent intense microbial activity. Mixing models confirmed higher reliance to a detritus-based food web for benthic organisms in the trawled areas. Standard Ellipse Areas (SEAc) as a measure of community niche width were slightly larger in trawled areas, likely due to higher generalism triggered by alteration/removal of the original benthic community.

  15. Influence of dreissenid mussels on catchability of benthic fishes in bottom trawls

    USGS Publications Warehouse

    Kocovsky, Patrick M.; Stapanian, Martin A.

    2011-01-01

    Inferring trends in true abundance of fish populations from catch per unit effort data requires either the knowledge of capture probability or the assumption that it is constant, both of which are unlikely contingencies. We developed and validated an index of catchability (a proxy measure for capture probability) from a long-term data set describing nearshore waters of western Lake Erie, and we used the index to test the hypothesis that catchability of four abundant benthic species captured in bottom trawls changed after the invasion of dreissenid mussels. We estimated daytime and nighttime catchability for 1972–1990 (predreissenid period) and 1991–2009 (dreissenid period); we then tested for differences between nighttime and daytime catchability in the predreissenid and dreissenid periods and the nighttime–daytime differential in catchability during the dreissenid period. We also tested relationships between Secchi depth and the catchability index via linear regression. Catchability indices for white perch Morone americana, yellow perch Perca flavescens, and trout-perch Percopsis omiscomaycus did not differ between daytime and nighttime during the predreissenid period. After establishment of dreissenids, all three of these species had lower daytime catchability than nighttime catchability and had positive nighttime–daytime differentials, indicating a shift toward higher nighttime catchability relative to daytime catchability. Changes in catchability indices for freshwater drum Aplodinotus grunniens were opposite the changes observed for the other three species, possibly because the freshwater drum is the only species that actively feeds on dreissenids. Catchability indices were negatively related to water clarity (Secchi depth) for three of the species. Our results are consistent with the hypothesis that catchability of the four most common benthic fish species captured in bottom trawls within nearshore waters of western Lake Erie changed after the

  16. When does fishing lead to more fish? Community consequences of bottom trawl fisheries in demersal food webs.

    PubMed

    van Denderen, P Daniel; van Kooten, Tobias; Rijnsdorp, Adriaan D

    2013-10-22

    Bottom trawls are a globally used fishing gear that physically disturb the seabed and kill non-target organisms, including those that are food for the targeted fish species. There are indications that ensuing changes to the benthic invertebrate community may increase the availability of food and promote growth and even fisheries yield of target fish species. If and how this occurs is the subject of ongoing debate, with evidence both in favour and against. We model the effects of trawling on a simple ecosystem of benthivorous fish and two food populations (benthos), susceptible and resistant to trawling. We show that the ecosystem response to trawling depends on whether the abundance of benthos is top-down or bottom-up controlled. Fishing may result in higher fish abundance, higher (maximum sustainable) yield and increased persistence of fish when the benthos which is the best-quality fish food is also more resistant to trawling. These positive effects occur in bottom-up controlled systems and systems with limited impact of fish feeding on benthos, resembling bottom-up control. Fishing leads to lower yields and fish persistence in all configurations where susceptible benthos are more profitable prey. Our results highlight the importance of mechanistic ecosystem knowledge as a requirement for successful management.

  17. When does fishing lead to more fish? Community consequences of bottom trawl fisheries in demersal food webs

    PubMed Central

    van Denderen, P. Daniel; van Kooten, Tobias; Rijnsdorp, Adriaan D.

    2013-01-01

    Bottom trawls are a globally used fishing gear that physically disturb the seabed and kill non-target organisms, including those that are food for the targeted fish species. There are indications that ensuing changes to the benthic invertebrate community may increase the availability of food and promote growth and even fisheries yield of target fish species. If and how this occurs is the subject of ongoing debate, with evidence both in favour and against. We model the effects of trawling on a simple ecosystem of benthivorous fish and two food populations (benthos), susceptible and resistant to trawling. We show that the ecosystem response to trawling depends on whether the abundance of benthos is top-down or bottom-up controlled. Fishing may result in higher fish abundance, higher (maximum sustainable) yield and increased persistence of fish when the benthos which is the best-quality fish food is also more resistant to trawling. These positive effects occur in bottom-up controlled systems and systems with limited impact of fish feeding on benthos, resembling bottom-up control. Fishing leads to lower yields and fish persistence in all configurations where susceptible benthos are more profitable prey. Our results highlight the importance of mechanistic ecosystem knowledge as a requirement for successful management. PMID:24004941

  18. USGS Lake Erie East Harbor bottom trawl data series, 1961-2011

    USGS Publications Warehouse

    ,

    2016-01-01

    The USGS Lake Erie Biological Station’s East Harbor sampling program began in 1961 with the commissioning of the research vessel Musky II. It is the longest known continuous trawl survey in Lake Erie. In addition to spanning over 50 years, the data series is unique for three prominent design elements: 1) sampling was conducted at three depth strata; 2) replicate trawl samples were collected at each depth stratum; and 3) sampling was conducted during both day and night. Unlike other trawl series collected in Lake Erie, and throughout the Great Lakes, the East Harbor program is the only one to combine these sampling practices in a single survey. In 2012, the original vessel used since the inception of the East Harbor program, the research vessel Musky II, was retired and replaced with a larger research vessel, Muskie. The change in vessel necessitated change in the trawl net and all of the rigging and hardware needed to tow it (LEBS, 2013). This effectively ended the time series of data, which were collected with the exact same vessel and sampling gear for 51 years. This historical data set has proven valuable for testing hypotheses about long-term ecological change and the impacts of non-native species invasions in the Great Lakes. Further, at various times through history it provided accurate predictions of recruitment for species, such as Yellow Perch, that support some of the most valuable fisheries in the Great Lakes. For future scientific endeavors, and to ensure this work is available to the public, we present here the entire data set from 1961 through 2011.

  19. Rapid Changes on Sediment Accumulation Rates within Submarine Canyons Caused By Bottom Trawling Activities

    NASA Astrophysics Data System (ADS)

    Puig, P.; Masque, P.; Martin, J.; Paradis, S.; Juan, X.; Toro, M.; Palanques, A.

    2014-12-01

    The physical disturbance of the marine sedimentary environments by commercial bottom trawling is a matter of concern. The direct physical effects of this fishing technique include scraping and ploughing of the seabed and increases of the near-bottom water turbidity by sediment resuspension. However, the quantification of the sediment that has been resuspended by this anthropogenic activity over years and has been ultimately exported across the margin remains largely unaddressed. The analysis of sediment accumulation rates from sediment cores collected along the axes of several submarine canyons in the Catalan margin (northwestern Mediterranean) has allowed to estimate the contribution of this anthropogenic activity to the present-day sediment dynamics. 210Pb chronologies, occasionally supported by 137Cs dating, indicate a rapid increase of sediment accumulation rates since the 1970s, in coincidence with a strong impulse in the industrialization of the trawling fleets of this region. Such increase has been associated to the enhanced delivery of sediment resuspended by trawlers from the shelves and upper slope regions towards the canyon's interior, and to the rapid technical development at that time, in terms of engine power and gear size. This change has been observed in La Fonera (or Palamós) Canyon at depths greater than 1700 m, while in other canyons it is restricted to shallower regions (~1000 m in depth) closer to fishing grounds. Two sampling sites from La Fonera and Foix submarine canyons that exhibited high sediment accumulation rates (0.6-0.7 cm/y) were reoccupied several years after the first chronological analyses. These two new cores reveal a second and more rapid increase of sediment accumulation rates in both canyons occurring circa 2002 and accounting for about 2 cm/y. This second change at the beginning of the XXI century has been attributed to a preferential displacement of the trawling fleet towards slope fishing grounds surrounding submarine

  20. Influence of bottom trawling on sediment resuspension in the `Grande-Vasière' area (Bay of Biscay, France)

    NASA Astrophysics Data System (ADS)

    Mengual, Baptiste; Cayocca, Florence; Le Hir, Pierre; Draye, Robin; Laffargue, Pascal; Vincent, Benoit; Garlan, Thierry

    2016-09-01

    Sea trials were performed on two zones with different fishing efforts on the continental shelf of the Bay of Biscay (`Grande-Vasière' area of muddy sand) in order to assess particulate matter resuspension and seabed disturbances (i.e., penetration, reworking, grain size changes) induced by different types of trawls. Optical and acoustic measurements made in the water column indicate a significant trawling-induced resuspension mainly due to the scraping action of doors. It manifests as a highly dynamic turbid plume confined near the seabed, where suspended sediment concentrations can reach 200 mg l-1. Concentration levels measured behind an "alternative" configuration (trawls with jumper doors instead of classical doors penetrating the sediment) are significantly lower (around 10-20 mg l-1), which indicates a potential limiting impact regarding the seabed. Grain size analyses of the surficial sediment led to highlight a potential reworking influence of bottom trawling. On the intensively trawled zone, this reworking manifests as an upward coarsening trend in the first 5 cm of the cores. A significant decrease in mud content (30 %) has been also witnessed on this zone between 1967 and 2014, which suggests an influence on the seabed evolution. The geometric analysis of bottom tracks (4-5-cm depth, 20-cm width) observed with a benthic video sledge was used to compute an experimental trawling-induced erosion rate of 0.13 kg m-2. This erosion rate was combined with fishing effort data, in order to estimate trawling-induced erosion fluxes which were then compared to natural erosion fluxes over the Grande-Vasière at monthly, seasonal and annual scales. Winter storms control the annual resuspended load and trawling contribution to annual resuspension is in the order of 1 %. However, results show that trawling resuspension can become dominant during the fishing high season (i.e., until several times the natural one in summer). In addition, the contribution of trawling

  1. Impact of Bottom Trawling on Deep-Sea Sediment Properties along the Flanks of a Submarine Canyon

    PubMed Central

    Martín, Jacobo; Puig, Pere; Masqué, Pere; Palanques, Albert; Sánchez-Gómez, Anabel

    2014-01-01

    The offshore displacement of commercial bottom trawling has raised concerns about the impact of this destructive fishing practice on the deep seafloor, which is in general characterized by lower resilience than shallow water regions. This study focuses on the flanks of La Fonera (or Palamós) submarine canyon in the Northwestern Mediterranean, where an intensive bottom trawl fishery has been active during several decades in the 400–800 m depth range. To explore the degree of alteration of surface sediments (0–50 cm depth) caused by this industrial activity, fishing grounds and control (untrawled) sites were sampled along the canyon flanks with an interface multicorer. Sediment cores were analyzed to obtain vertical profiles of sediment grain-size, dry bulk density, organic carbon content and concentration of the radionuclide 210Pb. At control sites, surface sediments presented sedimentological characteristics typical of slope depositional systems, including a topmost unit of unconsolidated and bioturbated material overlying sediments progressively compacted with depth, with consistently high 210Pb inventories and exponential decaying profiles of 210Pb concentrations. Sediment accumulation rates at these untrawled sites ranged from 0.3 to 1.0 cm y−1. Sediment properties at most trawled sites departed from control sites and the sampled cores were characterized by denser sediments with lower 210Pb surface concentrations and inventories that indicate widespread erosion of recent sediments caused by trawling gears. Other alterations of the physical sediment properties, including thorough mixing or grain-size sorting, as well as organic carbon impoverishment, were also visible at trawled sites. This work contributes to the growing realization of the capacity of bottom trawling to alter the physical properties of surface sediments and affect the seafloor integrity over large spatial scales of the deep-sea. PMID:25111298

  2. Evaluation of New Zealand's high-seas bottom trawl closures using predictive habitat models and quantitative risk assessment.

    PubMed

    Penney, Andrew J; Guinotte, John M

    2013-01-01

    United Nations General Assembly Resolution 61/105 on sustainable fisheries (UNGA 2007) establishes three difficult questions for participants in high-seas bottom fisheries to answer: 1) Where are vulnerable marine systems (VMEs) likely to occur?; 2) What is the likelihood of fisheries interaction with these VMEs?; and 3) What might qualify as adequate conservation and management measures to prevent significant adverse impacts? This paper develops an approach to answering these questions for bottom trawling activities in the Convention Area of the South Pacific Regional Fisheries Management Organisation (SPRFMO) within a quantitative risk assessment and cost : benefit analysis framework. The predicted distribution of deep-sea corals from habitat suitability models is used to answer the first question. Distribution of historical bottom trawl effort is used to answer the second, with estimates of seabed areas swept by bottom trawlers being used to develop discounting factors for reduced biodiversity in previously fished areas. These are used in a quantitative ecological risk assessment approach to guide spatial protection planning to address the third question. The coral VME likelihood (average, discounted, predicted coral habitat suitability) of existing spatial closures implemented by New Zealand within the SPRFMO area is evaluated. Historical catch is used as a measure of cost to industry in a cost : benefit analysis of alternative spatial closure scenarios. Results indicate that current closures within the New Zealand SPRFMO area bottom trawl footprint are suboptimal for protection of VMEs. Examples of alternative trawl closure scenarios are provided to illustrate how the approach could be used to optimise protection of VMEs under chosen management objectives, balancing protection of VMEs against economic loss to commercial fishers from closure of historically fished areas.

  3. Evaluation of New Zealand’s High-Seas Bottom Trawl Closures Using Predictive Habitat Models and Quantitative Risk Assessment

    PubMed Central

    Penney, Andrew J.; Guinotte, John M.

    2013-01-01

    United Nations General Assembly Resolution 61/105 on sustainable fisheries (UNGA 2007) establishes three difficult questions for participants in high-seas bottom fisheries to answer: 1) Where are vulnerable marine systems (VMEs) likely to occur?; 2) What is the likelihood of fisheries interaction with these VMEs?; and 3) What might qualify as adequate conservation and management measures to prevent significant adverse impacts? This paper develops an approach to answering these questions for bottom trawling activities in the Convention Area of the South Pacific Regional Fisheries Management Organisation (SPRFMO) within a quantitative risk assessment and cost : benefit analysis framework. The predicted distribution of deep-sea corals from habitat suitability models is used to answer the first question. Distribution of historical bottom trawl effort is used to answer the second, with estimates of seabed areas swept by bottom trawlers being used to develop discounting factors for reduced biodiversity in previously fished areas. These are used in a quantitative ecological risk assessment approach to guide spatial protection planning to address the third question. The coral VME likelihood (average, discounted, predicted coral habitat suitability) of existing spatial closures implemented by New Zealand within the SPRFMO area is evaluated. Historical catch is used as a measure of cost to industry in a cost : benefit analysis of alternative spatial closure scenarios. Results indicate that current closures within the New Zealand SPRFMO area bottom trawl footprint are suboptimal for protection of VMEs. Examples of alternative trawl closure scenarios are provided to illustrate how the approach could be used to optimise protection of VMEs under chosen management objectives, balancing protection of VMEs against economic loss to commercial fishers from closure of historically fished areas. PMID:24358162

  4. Estimation of Bottom Trawl Catch Efficiency for Two Demersal Fishes, Atlantic Croaker and White Perch in Chesapeake Bay

    EPA Science Inventory

    We present an efficiency analysis of a fisheries-independent demersal trawl survey in Chesapeake Bay, the largest estuary in the United States, that is presently being used for multi-species fisheries assessment and management. The manuscript presents an in situ analysis of demer...

  5. Estimation of Bottom Trawl Catch Efficiency for Two Demersal Fishes, Atlantic Croaker and White Perch in Chesapeake Bay

    EPA Science Inventory

    We present an efficiency analysis of a fisheries-independent demersal trawl survey in Chesapeake Bay, the largest estuary in the United States, that is presently being used for multi-species fisheries assessment and management. The manuscript presents an in situ analysis of demer...

  6. Marine debris in bottom trawl catches and their effects on the selectivity grids in the north eastern Mediterranean.

    PubMed

    Eryaşar, Ahmet Raif; Özbilgin, Hüseyin; Gücü, Ali Cemal; Sakınan, Serdar

    2014-04-15

    In this study composition of marine debris and their blocking potential on the selectivity grid systems deployed on demersal trawls were investigated in the north eastern Mediterranean. For this, a total of 132 hauls were examined in two fishing season between 20 September 2010 and 19 February 2012. Results showed that plastic items were the most abundant debris (73% in terms of weight) and they were followed by metals (10%). Because of plastics and packing debris, it is highly probable that grids may have been blocked in 85% of trawl hauls. The bathymetric and geographical variability in the quantity of debris were evaluated, and concluded that particularly in some areas where direction of currents and bottom topography favor deposition, such devices may easily be rendered ineffective by the plastics and packing debris in particular. To solve this problem, several solution proposals are submitted. Copyright © 2014 Elsevier Ltd. All rights reserved.

  7. Evaluating the Effect of Bottom Trawls in Pamlico River, North Carolina

    NASA Technical Reports Server (NTRS)

    Corbett, D. Reide; West, Terry; Clough, Lisa; Frank, James; Calfee, Worth

    2003-01-01

    The objective of this study is to evaluate and quantify the amount of sediment resuspension on shallow estuarine systems, with specific comparisons between natural and trawling-induced events. This aids in the assessment of water quality and sediment processes on a specific coastal system of North Carolina, providing a basis for future studies on other shallow estuarine ecosystems. Categorizing these sediment processes into distinct individual units (e.g. natural vs. anthropogenic) is an important component toward fully realizing proper management of our coastal habitats. Heavy trawling activity along North Carolina s coast is one of the major obstacles in management plans. Therefore, it is imperative to quantify the effects of trawling to gain a more specific understanding of the human impact on estuaries.

  8. Community stability within the St. Marys River fish community: Evidence from trawl surveys

    USGS Publications Warehouse

    Schaeffer, Jeffrey S.; Bowen, Anjanette K.; Fielder, David G.

    2017-01-01

    A trawl survey was conducted in the Saint Marys River during 2010–2011 and we compared our results to a prior trawl survey conducted during 1979–1983 to look for long-term changes in the fish community, especially in terms of changes induced by invasive species. We found no substantive temporal differences in fish density, fish biomass, or fish diversity; lower trawl biomass during 2010–2011 was likely a result of day versus night trawling. The Saint Marys River remains a center of high fish diversity, invasive species remain rare, and the system continues to exhibit overall long-term stability. Trawling captured a wide range of fish species, but was likely not an effective stock assessment tool for managed game fish because catch rates were low or variable for all game species except yellow perch. Trawling appeared to be an effective tool for sampling connecting channel diversity, especially when large numbers of individuals are needed for directed studies, but annual sampling would be needed to use data to assess recruitment.

  9. Species and size selectivity of two midwater trawls used in an acoustic survey of the Alaska Arctic

    NASA Astrophysics Data System (ADS)

    De Robertis, Alex; Taylor, Kevin; Williams, Kresimir; Wilson, Christopher D.

    2017-01-01

    Acoustic-trawl (AT) survey methods are widely used to estimate the abundance and distribution of pelagic organisms. This technique relies on estimates of size and species composition from trawl catches along with estimates of the acoustic properties of these animals to convert measurements of acoustic backscatter into animal abundance. However, trawls are selective samplers, and if the catch does not represent the size and species composition of the animals in the acoustic beam the resulting abundance estimates will be biased. We conducted an experiment to quantify trawl selectivity for species encountered during an AT survey of the Alaska Arctic. The pelagic assemblage in this environment was dominated by small young-of-the-year (age-0) fishes and jellyfish, which may be poorly retained in trawls. A large midwater trawl (Cantrawl) and a smaller midwater trawl (modified Marinovich) were used during the survey. The Marinovich was equipped with 8 small-mesh recapture nets which were used to estimate the probability that an individual that enters the trawl is retained. In addition, paired hauls were made with the Cantrawl and Marinovich to estimate the difference in selectivity between the two trawls. A statistical model was developed to combine the catches of the recapture nets and the paired hauls to estimate the length-dependent selectivity of the trawls for the most abundant species (e.g., age-0 fishes and jellyfish). The analysis indicated that there was substantial size and species selectivity: although the modified Marinovich generally had a higher catch per unit effort, many of the animals encountered in this environment were poorly retained by both trawls. The observed size and species selectivity of the trawls can be used to select appropriate nets for sampling pelagic fishes, and correct survey estimates for the biases introduced in the trawl capture process.

  10. Deep-sea ecosystem response to bottom trawling impacts: changes in sediment bioturbation patterns

    NASA Astrophysics Data System (ADS)

    Puig, P.; Martin, J.; Masque, P.; Mecho, A.; Company, J. B.; Palanques, A.

    2015-12-01

    Studies conducted in La Fonera (Palamós) submarine canyon (NW Mediterranean) evidence that trawling activities along the canyon flanks cause resuspension and transport of sediments towards the canyon axis. The analysis of a sediment core collected at 1750 m in 2002 showed a doubling of the sediment accumulation rate since the 1970s, coincident with the rapid industrialization of the local trawling fleet. This occurred along with a change from bioturbated texture to well-preserved sedimentary layering, interpreted as depositional pulses of trawling-induced sediment gravity flows. The good preservation of these structures was explained as a temporary hampering of biological mixing, resulting from suffocation of bioturbating fauna. The same canyon area was revisited a decade later (2011) and new data are consistent with the sedimentary regime shift during the 1970s, but also suggest that the accumulation rate during the last decade is even greater than expected, approaching ~2.4 cm/y (compared to ~0.25 cm/y pre-1970s). The X-radiograph image from the 2011 sediment core also indicates that bioturbation, if hampered in the 2002 core, has been reactivated later. Various ichnofabrics observable in the 2011 core testify to a diverse bioturbating fauna, including a scolitia resulting from the burrowing activity of an endobenthic echinoid. Remotely operated vehicle images collected along the canyon axis seafloor evidenced a large presence and densities of the burrowing sea urchin Brissopsis lyrifera. This species has also been found in high densities in the neighbor Blanes canyon axis, while it was absent from the adjacent open slope. However, historical data indicate that B. lyrifera was present in high numbers in the slope region in previous decades, suggesting that trawling activities have modified the distribution of this burrowing species and that the canyon environment is currently functioning as refuge area that offers a suitable environment for their proliferation.

  11. Improving the design of acoustic and midwater trawl surveys through stratification, with an application to Lake Michigan prey fishes

    USGS Publications Warehouse

    Adams, J.V.; Argyle, R.L.; Fleischer, G.W.; Curtis, G.L.; Stickel, R.G.

    2006-01-01

    Reliable estimates of fish biomass are vital to the management of aquatic ecosystems and their associated fisheries. Acoustic and midwater trawl surveys are an efficient sampling method for estimating fish biomass in large bodies of water. To improve the precision of biomass estimates from combined acoustic and midwater trawl surveys, sampling effort should be optimally allocated within each stage of the survey design. Based on information collected during fish surveys, we developed an approach to improve the design of combined acoustic and midwater trawl surveys through stratification. Geographic strata for acoustic surveying and depth strata for midwater trawling were defined using neighbor-restricted cluster analysis, and the optimal allocation of sampling effort for each was then determined. As an example, we applied this survey stratification approach to data from lakewide acoustic and midwater trawl surveys of Lake Michigan prey fishes. Precision of biomass estimates from surveys with and without geographic stratification was compared through resampling. Use of geographic stratification with optimal sampling allocation reduced the variance of Lake Michigan acoustic biomass estimates by 77%. Stratification and optimal allocation at each stage of an acoustic and midwater trawl survey should serve to reduce the variance of the resulting biomass estimates.

  12. Increasing sediment accumulation rates in La Fonera (Palamós) submarine canyon axis and their relationship with bottom trawling activities

    NASA Astrophysics Data System (ADS)

    Puig, P.; Martín, J.; Masqué, P.; Palanques, A.

    2015-10-01

    Previous studies conducted in La Fonera (Palamós) submarine canyon (NW Mediterranean) found that trawling activities along the canyon flanks cause resuspension and transport of sediments toward the canyon axis. 210Pb chronology supported by 137Cs dating applied to a sediment core collected at 1750 m in 2002 suggested a doubling of the sediment accumulation rate since the 1970s, coincident with the rapid industrialization of the local trawling fleet. The same canyon area has been revisited a decade later, and new data are consistent with a sedimentary regime shift during the 1970s and also suggest that the accumulation rate during the last decade could be greater than expected, approaching ~2.4 cm yr-1 (compared to ~0.25 cm yr-1 pre-1970s). These results support the hypothesis that commercial bottom trawling can substantially affect sediment dynamics and budgets on continental margins, eventually initiating the formation of anthropogenic depocenters in submarine canyon environments.

  13. Use of a fishery-independent trawl survey to evaluate distribution patterns of subadult sharks in Georgia

    USGS Publications Warehouse

    Belcher, C.N.; Jennings, Cecil A.

    2009-01-01

    We investigated the utility of a fishery-independent trawl survey for assessing a potential multispecies shark nursery in Georgia's nearshore and inshore waters. A total of 234 subadult sharks from six species were captured during 85 of 216 trawls. Catch rates and size distributions for subadult sharks and the ratio of neonates to juveniles were consistent among areas. The highest concentrations of subadult sharks occurred in creeks and sounds. Species composition varied among areas. The Atlantic sharpnose shark Rhizoprionodon terraenovae was the most abundant species in sound and nearshore stations, whereas the bonnethead Sphyrna tiburo was the most abundant species in creeks. The aggregate of other species occurred with higher frequency in the sounds and nearshore. Sampling characteristics of the trawl survey were compared with those from a fishery-independent longline survey of subadult sharks to assess the similarity of the two gears. A total of 193 subadult sharks from seven species were captured during 57 of 96 longline sets, whereas 52 subadults from four species were captured during 20 of 48 trawls. Selectivity and efficiency differed between the two gears. The trawl had lower catch rates, caught smaller sharks, and encountered a different suite of species than the longline. General seasonal trends in relative abundance also differed between the two gears; the longline showed an increasing trend in abundance, whereas the trawl showed a stable trend. Although trawls were not found to be efficient for sampling subadult sharks from most species, they can be a useful source of supplemental data.

  14. Organic biomarkers in deep-sea regions affected by bottom trawling: pigments, fatty acids, amino acids and carbohydrates in surface sediments from the La Fonera (Palamós) Canyon, NW Mediterranean Sea

    NASA Astrophysics Data System (ADS)

    Sañé, E.; Martín, J.; Puig, P.; Palanques, A.

    2013-12-01

    Deep-sea ecosystems are in general adapted to a limited variability of physical conditions, resulting in high vulnerability and slow recovery rates from anthropogenic perturbations such as bottom trawling. Commercial trawling is the most recurrent and pervasive of human impacts on the deep-sea floor, but studies on its consequences on the biogeochemistry of deep-sea sediments are still scarce. Pigments, fatty acids, amino acids and carbohydrates were analysed in sediments from the flanks of the La Fonera (Palamós) submarine canyon (NW Mediterranean Sea), where a commercial bottom trawling fishery has been active for more than 70 yr. More specifically, we investigated how trawling-induced sediment reworking affects the quality of sedimentary organic matter which reaches the seafloor and accumulates in the sediment column, which is fundamental for the development of benthic communities. Sediment samples were collected during two oceanographic cruises in spring and autumn 2011. The sampled sites included trawl fishing grounds as well as pristine (control) areas. We report that bottom trawling in the flanks of the La Fonera Canyon has caused an alteration of the quality of the organic matter accumulated in the upper 5 cm of the seafloor. The use of a wide pool of biochemical tracers characterized by different reactivity to degradation allowed for us to discriminate the long-term effects of trawl-induced sediment reworking from the natural variability caused by the seasonal cycle of production and sinking of biogenic particles. Differences between untrawled and trawled areas were evidenced by labile amino acids, while differences between spring and autumn samples were detected only by the more labile indicators chlorophyll a and monounsaturated fatty acids. These results suggest that changes in the biochemical composition of the sedimentary organic matter caused by bottom trawling can be more relevant than those associated with natural seasonality and pose serious

  15. Organic biomarkers in deep-sea regions affected by bottom trawling: pigments, fatty acids, amino acids and carbohydrates in surface sediments from the La Fonera (Palamós) Canyon, NW Mediterranean Sea

    NASA Astrophysics Data System (ADS)

    Sañé, E.; Martín, J.; Puig, P.; Palanques, A.

    2012-12-01

    Deep-sea ecosystems are in general adapted to a limited variability of physical conditions, resulting in high vulnerability and slow recovery rates from anthropogenic perturbations such as bottom trawling. Commercial trawling is the most recurrent and pervasive of human impacts on the deep-sea floor, but studies on its consequences on the biogeochemistry of deep-sea sediments are still scarce. Pigments, fatty acids, amino acids and carbohydrates were analyzed in sediments from the flanks of the La Fonera (Palamós) submarine canyon (NW Mediterranean Sea), where a commercial bottom trawling fishery has been active for more than 70 yr. More specifically, we investigated how trawling-induced sediment reworking affects the quality of sedimentary organic matter which reaches the seafloor and accumulates in the sediment column, which is fundamental for the development of benthic communities. Sediment samples were collected during two oceanographic cruises in spring and autumn 2011. The sampled sites included trawl fishing grounds as well as pristine (control) areas. We report that bottom trawling in the flanks of the La Fonera Canyon has caused an alteration of the quality of the organic matter accumulated in the upper 5 cm of the seafloor. The use of a wide pool of biochemical tracers characterized by different reactivity to degradation allowed us to discriminate the long-term effects of trawled-induced sediment reworking from the natural variability caused by the seasonal cycle of production and sinking of biogenic particles. Differences between untrawled and trawled areas were evidenced by labile amino acids, while differences between spring and autumn samples were detected only by the more labile indicators chlorophyll a and mono-unsaturated fatty acids. These results suggest that changes in the biochemical composition of the sedimentary organic matter caused by bottom trawling can be more relevant than those associated with natural seasonality and pose serious

  16. Long-term impact of bottom trawling on pelagic-benthic coupling in the southern North Sea (German Bight)

    NASA Astrophysics Data System (ADS)

    Friedrich, Jana; van Beusekom, Justus E. E.; Neumann, Andreas; Naderipour, Celine; Janssen, Felix; Ahmerkamp, Soeren; Holtappels, Moritz; Schueckel, Ulrike

    2016-04-01

    The southern North Sea, and the German Bight, has been systematically bottom-trawled at least since the late 19th century (Christiansen, 2009; Reiss et al., 2009; Kröncke 2011; Emeis et al., 2015, Neumann et al., 2016). As a result, benthic habitats and benthic biogenic structures created by bivalves, polychaetes and hydroids where destroyed or reduced. The parallel removal of hard substrate (gravel and boulders) avoids the resettlement of hard-substrate depended species. For example, the Oyster ground, a huge oyster bank a hundred years ago (Olsen, 1883), turned into a muddy depression today. In addition, shallow depth of max 40 m, strong tidal currents and frequent storms result in a high-energy environment with low sedimentation rates and recurrent sediment resuspension. The decrease in benthic filtering capacity by disturbance in epifauna and bottom roughness (Callaway et al., 2007) apparently influence pelagic-benthic coupling of biogeochemical fluxes. Heip et al. (1995) indicate that benthic respiration at depths prevailing in the German Bight accounts for 10-40% of total respiration, whereas pelagic respiration accounts for 60-90%. Previous estimates are in the middle of this range (Heip et al., 1995). To test these hypotheses and to assess the partitioning of benthic and pelagic processes, and the factors influencing organic matter mineralization, we measured pelagic production and respiration based on Winkler titration, in-situ benthic fluxes using chamber landers, we did ex-situ incubations of intact sediment cores and analysed still images from a towed benthic video sled. In addition, O2 fluxes in permeable sediments were estimated by integrating the volumetric rate measurements of the upper sediment layer over in-situ microsensor-measured O2 penetration depth. Our current results show significant seasonality in benthic respiration, with highest rates in summer and lowest rates in winter. No significant differences in total benthic respiration rates

  17. Automated area segmentation for ocean bottom surveys

    NASA Astrophysics Data System (ADS)

    Hyland, John C.; Smith, Cheryl M.

    2015-05-01

    In practice, environmental information about an ocean bottom area to be searched using SONAR is often known a priori to some coarse level of resolution. The SONAR search sensor then typically has a different performance characterization function for each environmental classification. Large ocean bottom surveys using search SONAR can pose some difficulties when the environmental conditions vary significantly over the search area because search planning tools cannot adequately segment the area into sub-regions of homogeneous search sensor performance. Such segmentation is critically important to unmanned search vehicles; homogenous bottom segmentation will result in more accurate predictions of search performance and area coverage rate. The Naval Surface Warfare Center, Panama City Division (NSWC PCD) has developed an automated area segmentation algorithm that subdivides the mission area under the constraint that the variation of the search sensor's performance within each sub-mission area cannot exceed a specified threshold, thereby creating sub-regions of homogeneous sensor performance. The algorithm also calculates a new, composite sensor performance function for each sub-mission area. The technique accounts for practical constraints such as enforcing a minimum sub-mission area size and requiring sub-mission areas to be rectangular. Segmentation occurs both across the rows and down the columns of the mission area. Ideally, mission planning should consider both segmentation directions and choose the one with the more favorable result. The Automated Area Segmentation Algorithm was tested using two a priori bottom segmentations: rectangular and triangular; and two search sensor configurations: a set of three bi-modal curves and a set of three uni-modal curves. For each of these four scenarios, the Automated Area Segmentation Algorithm automatically partitioned the mission area across rows and down columns to create regions with homogeneous sensor performance. The

  18. Functional gains of including non-commercial epibenthic taxa in coastal beam trawl surveys: A note

    NASA Astrophysics Data System (ADS)

    Brind'Amour, Anik; Rouyer, Armelle; Martin, Jocelyne

    2009-05-01

    The development of ecosystem-based indicators requires the broadening of a view of the community, from fish species to all the species (macrobenthic and fish) correctly captured by a given sampling gear. Many scientific surveys already have such integrated databases. The present note aims to demonstrate that existing databases, herein from dedicated coastal nursery surveys, are actually underexploited. Such databases contain information on non-commercial taxa, which could greatly improve our knowledge on the organisation and functioning of coastal ecosystems. Using two datasets, a "complete" dataset composed of commercial and not-commercial epibenthic trawled species (fish and invertebrate) and a "subset" dataset characterized by commercial and routinely surveyed species (mainly fish and cephalopods), different measures of functional diversity are compared to identify the functional gains of including epibenthic species. The results show that, when included in the analyses, epibenthic taxa provide gains of functional information, associated mainly with the community feeding traits, i.e. organisms composing the primary and secondary consumer levels of the coastal nursery food web. Failure to include some of the primary (zooplanktivores and suspension feeders) and secondary consumers (detritivores-scavengers) in coastal survey analyses may, for instance, hamper our understanding of energy flux between the benthic and water column compartments of these ecosystems. The results also suggest that the exclusion of some taxa associated with these two food web compartments, may lead to the underestimation of the functional redundancy in coastal ecosystems.

  19. Surface trawl survey for U.S. origin Atlantic salmon Salmo salar.

    PubMed

    Sheehan, T F; Renkawitz, M D; Brown, R W

    2011-08-01

    A surface trawl survey (2001-2005) in Penobscot Bay, Maine, U.S.A., and the nearshore Gulf of Maine waters was conducted to investigate early marine dynamics of a hatchery-dependent Atlantic salmon Salmo salar population from a severely modified river system. Data generated were used to evaluate the effect of stocking location and time on migration success and to describe the migratory pathways and environments that post-smolts traverse. Significant differences in early migration success were detected among different stocking groups, but subsequent marine survival was independent of stocking group. While the post-smolt population was primarily composed of hatchery origin smolt-stocked fish, other life-stage stocking strategies (i.e. parr stocking) represented a higher proportion of the population than previously assumed. Catch distribution suggests evidence of an initial marine migratory pathway out of the dynamic Penobscot Bay environment. The hypothesized benefits of a predator refuge based on the co-occurring species complex is considered minimal for emigrating post-smolts given a mismatch in the size overlap among species and low abundance of other co-occurring diadromous populations. These data can be used to modify current management actions to optimize S. salar recovery and inform future research agendas.

  20. 36. Historic American Buildings Survey L. C. Durette, Photographer BOTTOM ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    36. Historic American Buildings Survey L. C. Durette, Photographer BOTTOM OF SOUTH WEST CORNER POST 2nd. FLOOR SHOWING CONSTRUCTION OF OVERHANG - Doe Garrison, Lamprey River & Great Bay, Newmarket, Rockingham County, NH

  1. LJ's 2010 Budget Survey: Bottoming Out?

    ERIC Educational Resources Information Center

    Kelley, Michael

    2011-01-01

    In this article, the author presents the results of "Library Journal's" 2010 budget survey. The overall trend in FY10 indicated that 72 percent of survey respondents said their budget had been cut, and 43 percent had staff cuts. Among libraries serving populations above one million, these figures were even more acute, with 86 percent reporting…

  2. SUMMER FISH COMMUNITY OF THE COASTAL NORTHERN GULF OF MEXICO: CHARACTGERIZATION OF A LARGE-SCALE TRAWL SURVEY

    EPA Science Inventory

    This paper summarizes the trawled fish assemblage collected during 1992 - 1994 at 119 locations in the northern Gulf of Mexico. The 367 collection sites were located adjacent to five states and represented seven estuarine categories. Fish were collected using an otter trawl durin...

  3. SUMMER FISH COMMUNITY OF THE COASTAL NORTHERN GULF OF MEXICO: CHARACTGERIZATION OF A LARGE-SCALE TRAWL SURVEY

    EPA Science Inventory

    This paper summarizes the trawled fish assemblage collected during 1992 - 1994 at 119 locations in the northern Gulf of Mexico. The 367 collection sites were located adjacent to five states and represented seven estuarine categories. Fish were collected using an otter trawl durin...

  4. Survey of Lake Ontario bottom sediment off Rochester, New York, to define the extent of jettisoned World War II material and its potential for sediment contamination

    USGS Publications Warehouse

    Kennedy, Gregory; Kappel, William M.

    2000-01-01

    Military-type mat??riel was recovered from the bottom of Lake Ontario near Rochester, N.Y., during bottom-trawl, fish-stock surveys at depths of 75 to 180 feet each year from 1978 through 1996. The recovered mat??riel included many shell-detonator nose cones (2 inches in diameter by about 3.5 inches long); several electronic components; one corroded box of detonators; a corrugated container of mercury-filled capsules; and corroded batteries. Most of the recovered mat??riel has been identified as defective components of shell detonators (proximity-fuze assemblies) that were jettisoned in the lake to protect them from discovery during World War II. Side-scan SONAR, metal-detector, and ROV (remotely-operated-vehicle) surveys found no evidence of any large piles of mat??riel containing potentially hazardous, toxic, or polluting materials within the 17-square-mile study site. Many scattered magnetic anomalies were detected in this area, but chemical analysis of bottom sediment and of zebra- and quagga-mussel (Dreissena spp.) tissue indicate that the concentrations of mercury and other heavy metals are within the previously documented ranges for Lake Ontario sediment. The failure of ROV videos and of SCUBA-diver surveys and probes of the lake bottom to locate any debris indicates that most, if not all, of the debris is scattered and buried under a layer of fine-grained sediment and, possibly, mussels.

  5. Sidescan-sonar mapping of benthic trawl marks on the shelf and slope off Eureka, California

    USGS Publications Warehouse

    Friedlander, A.M.; Boehlert, G.W.; Field, M.E.; Mason, J.E.; Gardner, J.V.; Dartnell, P.

    1999-01-01

    The abundance and orientation of trawl marks was quantified over an extensive portion (>2700 km2) of the Eureka, California, outer shelf and slope, an important commercial bottom trawling ground for such high-value species as rockfish, sole, and sablefish. Fishing logbook data indicate that the entire reporting area was trawled about one and a half times on an average annual basis and that some areas were trawled over three times annually. High-resolution sidescan-sonar images of the study area revealed deep gouges on the seafloor, caused by heavy steel trawl doors that act to weigh down and spread open the bottom trawls. These trawl marks are commonly oriented parallel to bathymetric contours and many could be traced for several kilometers. Trawl marks showed a quadratic relationship in relation to water depth, with the greatest number of trawl marks observed at ~400 m. There was a significant positive correlation between the number of trawl marks observed on the sidescan images and the number of annual trawl hours logged within reporting areas. This finding indicates that acoustic remote sensing is a promising independent approach to evaluate fishing effort on a scale consistent with commercial fishing activities. Bottom trawling gear is known to modify seafloor habitats by altering benthic habitat complexity and by removing or damaging infauna and sessile organisms. Identifying the extent of trawling in these areas may help determine the effects of this type of fishing gear on the benthos and develop indices of habitat disturbance caused by fishing activities.

  6. Environmental DNA from Seawater Samples Correlate with Trawl Catches of Subarctic, Deepwater Fishes.

    PubMed

    Thomsen, Philip Francis; Møller, Peter Rask; Sigsgaard, Eva Egelyng; Knudsen, Steen Wilhelm; Jørgensen, Ole Ankjær; Willerslev, Eske

    2016-01-01

    Remote polar and deepwater fish faunas are under pressure from ongoing climate change and increasing fishing effort. However, these fish communities are difficult to monitor for logistic and financial reasons. Currently, monitoring of marine fishes largely relies on invasive techniques such as bottom trawling, and on official reporting of global catches, which can be unreliable. Thus, there is need for alternative and non-invasive techniques for qualitative and quantitative oceanic fish surveys. Here we report environmental DNA (eDNA) metabarcoding of seawater samples from continental slope depths in Southwest Greenland. We collected seawater samples at depths of 188-918 m and compared seawater eDNA to catch data from trawling. We used Illumina sequencing of PCR products to demonstrate that eDNA reads show equivalence to fishing catch data obtained from trawling. Twenty-six families were found with both trawling and eDNA, while three families were found only with eDNA and two families were found only with trawling. Key commercial fish species for Greenland were the most abundant species in both eDNA reads and biomass catch, and interpolation of eDNA abundances between sampling sites showed good correspondence with catch sizes. Environmental DNA sequence reads from the fish assemblages correlated with biomass and abundance data obtained from trawling. Interestingly, the Greenland shark (Somniosus microcephalus) showed high abundance of eDNA reads despite only a single specimen being caught, demonstrating the relevance of the eDNA approach for large species that can probably avoid bottom trawls in most cases. Quantitative detection of marine fish using eDNA remains to be tested further to ascertain whether this technique is able to yield credible results for routine application in fisheries. Nevertheless, our study demonstrates that eDNA reads can be used as a qualitative and quantitative proxy for marine fish assemblages in deepwater oceanic habitats. This relates

  7. Environmental DNA from Seawater Samples Correlate with Trawl Catches of Subarctic, Deepwater Fishes

    PubMed Central

    Thomsen, Philip Francis; Møller, Peter Rask; Sigsgaard, Eva Egelyng; Knudsen, Steen Wilhelm; Jørgensen, Ole Ankjær; Willerslev, Eske

    2016-01-01

    Remote polar and deepwater fish faunas are under pressure from ongoing climate change and increasing fishing effort. However, these fish communities are difficult to monitor for logistic and financial reasons. Currently, monitoring of marine fishes largely relies on invasive techniques such as bottom trawling, and on official reporting of global catches, which can be unreliable. Thus, there is need for alternative and non-invasive techniques for qualitative and quantitative oceanic fish surveys. Here we report environmental DNA (eDNA) metabarcoding of seawater samples from continental slope depths in Southwest Greenland. We collected seawater samples at depths of 188–918 m and compared seawater eDNA to catch data from trawling. We used Illumina sequencing of PCR products to demonstrate that eDNA reads show equivalence to fishing catch data obtained from trawling. Twenty-six families were found with both trawling and eDNA, while three families were found only with eDNA and two families were found only with trawling. Key commercial fish species for Greenland were the most abundant species in both eDNA reads and biomass catch, and interpolation of eDNA abundances between sampling sites showed good correspondence with catch sizes. Environmental DNA sequence reads from the fish assemblages correlated with biomass and abundance data obtained from trawling. Interestingly, the Greenland shark (Somniosus microcephalus) showed high abundance of eDNA reads despite only a single specimen being caught, demonstrating the relevance of the eDNA approach for large species that can probably avoid bottom trawls in most cases. Quantitative detection of marine fish using eDNA remains to be tested further to ascertain whether this technique is able to yield credible results for routine application in fisheries. Nevertheless, our study demonstrates that eDNA reads can be used as a qualitative and quantitative proxy for marine fish assemblages in deepwater oceanic habitats. This relates

  8. Seismicity surveys with ocean bottom seismographs off Western Canada

    SciTech Connect

    Hyndman, R.D.; Rogers, G.C.

    1981-05-10

    Three arrays of ocean bottom seismographs have been deployed to study the seismicity at the northern end of the Juan de Fuca ridge system off western Canada. Nearly 100 events were located with estimated accuracies generally better than +- 10 km, all lying on or near the en echelon ridge-transform fault plate boundaries as defined in this area by the magnetic anomalies, the seafloor morphology and by other geophysical data. The depths of 12 events were determined to lie between 2 and 6 km below the top of the crust. The seismograms exhibit clear P and S wave arrivals along with phases that involve P to S and sometimes S to P conversion probably at the base of the sediments beneath the instruments. The event magnitudes have been estimated from signal duration using four calibration events that were well recorded by a land station. The magnitude estimates permit the determination of rough magnitude-frequency of occurrence relations over the magnitude range of 1 to 3 that are in surprisingly good agreement with the recurrence relations for the area at larger magnitudes from 75 years of land station data. The mean P wave velocity in the uppermost mantle from the earthquake data recorded by the sea floor arrays is 7.6 km s/sup -1/ and the mean V/sub p//V/sub s/ ratio is 1.71 or a Poisson's ratio of 0.24.

  9. Effects of closed trawl fishery areas on some elasmobranch species in the Cantabrian Sea

    NASA Astrophysics Data System (ADS)

    Rodríguez-Cabello, C.; Sánchez, F.; Serrano, A.; Olaso, I.

    2008-07-01

    This study examines the effects of certain closed areas to the trawl fishery on some Rajidae species and small-spotted catshark in the southern area of the Bay of Biscay. The results are based on abundance index (number/haul) and catch length composition obtained from a series of bottom trawl surveys carried out in the area (1993-2005). Abundance trends are similar considering or not closed areas, but with much lower values excluding closed areas. The length distributions revealed that in some of the species like Scyliorhinus canicula the larger specimens were the most affected by this decrease in number. Finally, the effects and consequences of one of these marine protected areas (MPAs), an artificial reef were examined in more detail for all the fishes and invertebrates. The analysis of the yield series showed an increase in total biomass after the placement of the reefs not only for S. canicula and rays but also teleosts fishes like Pagellus acarne, Trachurus trachurus, Mullus surmuletus and Trachinus draco and particularly invertebrates (sea urchins). On the contrary, the main target species of the trawl fishery (hake, monkfish and megrim among others) did not increase.

  10. A temperature probe survey on the Louisiana shelf: Effects of bottom-water temperature variations

    SciTech Connect

    Cathles, L.M. ); Nunns, A.G. )

    1991-01-01

    A survey of temperature gradients in the uppermost sediments of the Louisiana continental shelf was done in 1983 by Gulf Oil Corporation, using a 5-m-long temperature probe. The survey covered 450 mi{sup 2}, with an average grid spacing of less than 1 mi. The purpose was to detect heat flow anomalies due to subsurface fluid flow. However, thermal perturbations due to seasonal variation of bottom-water temperature mask the temperature gradients due to geological heat flow. Bottom-water temperature variations similar to those recorded near the survey area in 1963-1965 explain most of the observed spatial and temporal changes in shallow temperature-depth profiles. The data set from this detailed survey has been donated to a publicly accessible scientific database, to spur research into heat flow measurement on continental shelves.

  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

    . Estimates of the midwater stocks, coinciding with the spring and fall bottom trawl surveys, indicated that between 20 and 30% of the total biomass was in midwater.

  12. The impact of shrimp trawling and associated sediment resuspension in mud dominated, shallow estuaries

    SciTech Connect

    Dellapenna, Timothy M.; Allison, Mead A.; Gill, Gary A.; Lehman, Ronald D.; Warnken, Kent W.

    2006-07-18

    To address the relative importance of shrimp trawling on seabed resuspension and bottom characteristics in shallow estuaries, a series of disturbance and monitoring experiments were conducted at a bay bottom mud site (2.5 m depth) in Galveston Bay, Texas in July 1998 and May 1999. Based on pre- and post-trawl sediment profiles of 7Be; pore water dissolved oxygen and sulfide concentration; and bulk sediment properties, it was estimated that the trawl rig, including the net, trawl doors, and ‘‘tickler chain,’’ excavate the seabed to a maximum depth of approximately 1.5 cm, with most areas displaying considerably less disturbance. Water column profile data in the turbid plume left by the trawl in these underconsolidated muds (85e90% porosity; <0.25 kPa undrained shear strength) demonstrate that suspended sediment inventories of up to 85e90 mg/cm2 are produced immediately behind the trawl net; an order of magnitude higher than pre-trawl inventories and comparable to those observed during a 9e10 m/s wind event at the study site. Plume settling and dispersion caused suspended sediment inventories to return to pre-trawl values about 14 min after trawl passage in two separate experiments, indicating particles re-settle primarily as flocs before they can be widely dispersed by local currents. As a result of the passage of the trawl rig across the seabed, shear strength of the sediment surface showed no significant increase, suggesting that bed armoring is not taking place and the trawled areas will not show an increase in critical shear stress.

  13. Effects of commercial otter trawling on the physical environment of the southeastern Bering Sea

    NASA Astrophysics Data System (ADS)

    Brown, Eloise J.; Finney, Bruce; Dommisse, Michaela; Hills, Sue

    2005-06-01

    The effects of commercial bottom trawling on the physical environment were investigated in a sandy habitat at ˜26-m water depth in the southeastern Bering Sea. We compared an area closed to trawling for 10 years with an adjacent commercial fishery area, examined the immediate effects of experimental trawling on sediment properties, and compared bottom trawling to natural disturbance by waves. The sediments in the top 3 cm of the fished area were slightly better sorted, less variable, and contained fewer fine grains than those of the closed area. Relative to controls, no shift in means was detected immediately after experimental trawling, but significant increases in variability occurred for several grain size and organic matter parameters. Wave disturbance to the study area was persistent and of greater magnitude than disturbance associated with commercial trawling. However, the trawl season occurred at a time of year when sediment resuspension by waves was diminished. Previous work suggested that such trawling-related factors have important biological consequences and account for the different benthic communities observed between trawled and closed areas. Given the physical setting, it is difficult to explain our subtle but significant results by purely physical processes. We hypothesize that the differences in sediment characteristics could result from a biological feedback process, where trawling results in different communities which in turn result in different sediment mixing and bioturbation rates, thereby influencing grain size parameters and labile carbon distributions. Functional differences in the benthic communities are consistent with the observed differences in sedimentary characteristics. This study is unique in identifying potential trawling effects in sandy high-energy environments, and suggests that interactions between physical and biological processes should be addressed in future studies.

  14. Coupling of ocean bottom seismometers to sediment: results of tests with the U.S. Geological Survey ocean bottom seismometer

    USGS Publications Warehouse

    Trehu, Anne M.

    1985-01-01

    The response of an ocean bottom seismometer (OBS) to a transient pull that excites the natural OBS-sediment coupling resonance can be modeled as a mass-spring-dashpot system in which the resonant frequency and damping are functions of instrument mass and bearing radius and of the physical properties of the sediment (primarily the shear modulus). For the very soft sediments sometimes found on the sea floor, this resonance may be within the main frequency band of interest (2 to 15 Hz) for many common instrument configurations. To test the model and to find an anchor that would shift the coupling resonance to a higher frequency and decrease its amplitude, we conducted a series of tests which measured the response of the vertical and horizontal components of the U.S. Geological Survey OBS to transient pulls as a function of anchor configuration and sediment properties. The tested anchors included a concrete “flowerpot,” a tripod, a plate, and a perforated plate. Sites were on soft, organic-rich ooze and on firm sand. Several small shots were also fired at the ooze site in order to compare the response of the plate and “flowerpot” anchors to seismic signals. For a given anchor at a given site, the observed response was very repeatable. We found that the model predicts the vertical coupling response quite well and that good vertical coupling can be achieved with the plate or perforated-plate anchors. The response to the horizontal pulls, however, was similar and resonant for all anchors.

  15. 78 FR 9024 - Sea Turtle Conservation; Shrimp Trawling Requirements

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-02-07

    ..., pusher-head trawls, and wing nets (butterfly trawls) rigged for fishing to use turtle excluder devices... (77 FR 27411) that would require all skimmer trawls, pusher-head trawls, and wing nets (butterfly... trawls, pusher-head trawls, and wing nets (butterfly trawls) will be collectively referred to as skimmer...

  16. Benthic microbial abundance and activities in an intensively trawled ecosystem (Thermaikos Gulf, Aegean Sea)

    NASA Astrophysics Data System (ADS)

    Polymenakou, Paraskevi N.; Pusceddu, Antonio; Tselepides, Anastasios; Polychronaki, Thalia; Giannakourou, Antonia; Fiordelmondo, Carla; Hatziyanni, Eleni; Danovaro, Roberto

    2005-12-01

    Abundance of benthic bacteria, heterotrophic nanoflagellates and ciliates, extracellular enzymatic activities, bacterial C production, C mineralisation and sediment community oxygen consumption rates were measured in the Thermaikos Gulf (Northeastern Mediterranean), before (September 2001), and during intense trawling activities (October 2001 and February 2002). The biochemical composition of sedimentary organic matter has revealed that bottom trawling had an effect on the trophic state of Thermaikos Gulf. Changes on the benthic microbial food web were also recorded, during the three sampling seasons. Even though trawling-induced sediment resuspension did not alter significantly the abundance of the microbial components, with the exception of the most impacted station, it determined changes regarding their relative importance. Thus, the ratios of bacterium to nanoflagellates and ciliate to nanoflagellates abundance increased in the trawled stations, causing a sudden increase in bacterial C production, in comparison to the non-trawled station. Four months later, the effects of trawling on the microbial food web were less evident, masked possibly by the drastic decrease in the water temperature. The results of the present work suggest that bottom trawling induces alteration of the sedimentological variables and can be considered as a factor affecting the function of the microbial food web in marine coastal ecosystems. These alterations cause faster mobilisation of organic C buried in the sediment and increase nutrient concentrations and availability in the system, thus inducing an effect that could lead to coastal eutrophication.

  17. Bathyal demersal fishes of Charlie Gibbs Fracture Zone region (49-54°N) of the Mid-Atlantic Ridge, I: Results from trawl surveys

    NASA Astrophysics Data System (ADS)

    Cousins, Nicola J.; Shields, Mark A.; Crockard, Deborah; Priede, Imants G.

    2013-12-01

    Demersal fishes were sampled by single-warp otter trawl (OTSB) at three sites on the Mid-Atlantic Ridge (MAR), to the northeast (NE), northwest (NW) and southeast (SE) of the Charlie-Gibbs Fracture Zone at approximately 2500 m depth. The mean abundance was 4109 fish km-2 (SD 3714) and biomass 897.1 kg km-2 (SD 842.9) compared with 1996 fish km-2 (SD 1497) and 721.2 kg km-2 (SD 387) at the same depth on the Porcupine Seabight (PSB) segment of the NE Atlantic Ocean margin from previous studies. There was no significant difference in biomass or abundance between the three sites on the MAR, nor in comparison with the ocean margin. A total of fish 22 species were recorded at the three MAR sites with evidence of highest species richness at the SE site. No unique species were found on the ridge; but there were differences in species composition between the PSB and the MAR. Coryphaenoides brevibarbis and Antimora rostrata were important at both the NE and NW trawl sites on the MAR whereas Halosauropsis macrochir was most important in the SE. We conclude that the MAR is an important habitat for species otherwise confined to narrow strips of appropriate depth around the North Atlantic Ocean margins. The MAR supports similar population densities to ocean margin settings but with differences in relative importance of different species between regions.

  18. Most microbeads in a preliminary survey of personal care products are smaller than the typical 330µm trawl mesh size used in surface water surveys

    NASA Astrophysics Data System (ADS)

    Conkle, J. L.; Baez-Del Valle, C.; Turner, J.

    2016-02-01

    Research on plastic debris in aquatic environments, particularly the ocean, has recently exploded due to our emerging understanding of their ubiquitous presence and organismal effects. One study estimated that hundreds of thousands of tons of plastic float at our ocean surface, while another estimated that up to 12.7 million metric tons enter the ocean in a year. These studies produced reasonable estimates of oceanic loads, but research is needed to understand the sources and properties of plastics, particularly microplastics, entering the environment. In this preliminary study, polyethylene (PE) microbeads from 6 facial scrubs, 4 body washes and 3 toothpaste products were extracted and quantified by mass and particle count for the following size classes: 50, 100, 200, 300, 400, 500 and 1000µm. Within the product classes, roughly half (face scrub, 55% and body wash, 48%) to nearly all (toothpaste, 97%) of PE microbeads on a mass basis were smaller than 300µm in diameter. When examining the size distribution by particle count, the results were even more astounding. Nearly all PE microbeads were smaller than 300µm for face scrub (95%), body wash (97%) and toothpaste (100%). The 300µm particle diameter is significant, as major surveys in the published literature (Eriksen et al., 2014; Law et al, 2014) used 330µm or greater mesh size to sample plastic debris and estimate oceanic plastic loads. Therefore, these published surveys, which are some of our best estimates of plastic debris at the ocean surface, likely underestimate total environmental loads because they may exclude half of the mass and nearly all of the individual PE microbead particles that enter our waste stream and potentially surface waters after the use of personal care products.

  19. Behaviour of fish by-catch in the mouth of a crustacean trawl.

    PubMed

    Queirolo, D; Gaete, E; Montenegro, I; Soriguer, M C; Erzini, K

    2012-06-01

    The behaviour of fish by-catch was recorded and characterized by in situ observations in the mouth of a crustacean trawl using an underwater camera system with artificial light, at depths between 106 and 461 m, along the central coast of Chile. The groups or species studied were rattails (family Macrouridae), Chilean hake Merluccius gayi gayi, sharks (orders Carcharhiniformes and Squaliformes), skates (family Rajidae), flatfishes (genus Hippoglossina) and small benthopelagic and demersal fishes (orders Osmeriformes, Stomiiformes, Gadiformes, Ophidiiformes and Perciformes). The fish behaviour was categorized in terms of (1) position in the water column, (2) initial orientation with respect to the trawl, (3) locomotion and (4) swimming speed with respect to the trawl. Rattails, sharks, skates and flatfishes were passive in response to the trawl and showed similar behavioural patterns, with most fishes observed sitting or touching the bottom with no swimming or other activity. Merluccius gayi gayi was the most active species, displaying a wide combination of behavioural responses when the trawl approached. This species showed several behavioural patterns, mainly characterized by swimming forward at variable speed. A fraction of small bentho-pelagic and demersal fishes also showed an active behaviour but always at lower speed than the trawl. The species-specific differences in behaviour in the mouth of the trawl suggest that improvements at the level of the footrope can be made to reduce by-catch, especially of passive species.

  20. Trawling disturbance on the isotopic signature of a structure-building species, the sea urchin Gracilechinus acutus (Lamarck, 1816)

    NASA Astrophysics Data System (ADS)

    González-Irusta, José M.; Preciado, Izaskun; López-López, Lucia; Punzón, Antonio; Cartes, Joan E.; Serrano, Alberto

    2014-08-01

    Bottom trawling is one of the main sources of anthropogenic disturbance in benthic habitats with important direct and indirect effects on the ecosystem functional diversity. In this study, the effect of this impact on a structure-building species, the sea urchin Gracilechinus acutus, was studied in the Central Cantabrian Sea (southern Bay of Biscay) comparing its isotopic signature and additional population descriptors across different trawling pressures. Trawling disturbance had a significant effect on the studied descriptors. In trawling areas, this urchin showed significantly lower values of biomass and mean size and significantly higher values of fullness index. Moreover, the trawling disturbance effect was also significant in the isotopic signature of G. acutus. Urchins inhabiting untrawled areas showed significant lower values of δ15N than urchins dwelling areas under trawling pressure. The urchins' isotopic enrichment increased along the species ontogeny regardless of the trawling effort level. Stable isotope analyses are a suitable tool to detect trawling disturbance on the trophic pathways but do not suffice to explain these changes, especially if there is a lack of baseline information.

  1. Near-bottom magnetic surveys around hydrothermal sites in the southern Mariana Trough

    NASA Astrophysics Data System (ADS)

    Nogi, Y.; Mochizuki, N.; Okino, K.; Asada, M.

    2011-12-01

    Near-bottom magnetic survey is an effective method to reveal detailed magnetic anomaly features of seafloor. The measurements of three-components of the geomagnetic field by using AUV "URASHIMA" were conducted during the YK-09-08 cruise in the southern Mariana Trough in order to detect signals of hydrothermally altered rocks. During the cruise, vector geomagnetic field are successfully obtained along the all dive tracks with the information of the vehicle's attitude. Total intensities of geomagnetic field by the overhauser magnetometer were also conducted, but the data are only collected along almost E-W oriented observation lines due to the sensitivity of the sensor. The distribution of crustal magnetization are estimated using downward component of magnetic anomalies by the inversion method. The distribution of low crustal magnetization are almost coincide with the area around hydrothermal vent sites from on ridge to off ridge area, and most likely indicate signs of hydrothermally altered rocks. The distribution of low crustal magnetization on ridge are almost parallel to the the strike of ridge axis implying tectonic control of hydrothermal vent sites.

  2. The organizational and operational boundaries of triple bottom line reporting: a survey.

    PubMed

    Archel, Pablo; Fernández, Manuel; Larrinaga, Carlos

    2008-01-01

    This article responds to Gray's (2002) call for normative research on social and environmental accounting (SEA) and Parker's (2005) call for active engagement in the process of designing SEA systems. More specifically, our investigation focuses on the study of boundary setting for triple bottom line (TBL) reporting, an issue that has been given more attention by practitioners than by researchers. The study reviews the consequences of boundary setting for the discharge of organizational accountability, from which it develops a framework to investigate TBL reporting boundaries and then reports on an empirical survey of best practice. It concludes that organizations are strategically setting and disclosing their boundaries instead of discharging their accountability and argues that such strategies have far-reaching consequences, because reporting boundaries are not only reflective of organizations but also have a constitutive role in their definition. A further consequence is that it calls into question the use of voluntary labeling, such as "in accordance" with Global Reporting Initiative; one implication being that further research into technical developments in TBL reporting could contribute to the discharge of organizational accountability.

  3. The Organizational and Operational Boundaries of Triple Bottom Line Reporting: A Survey

    NASA Astrophysics Data System (ADS)

    Archel, Pablo; Fernández, Manuel; Larrinaga, Carlos

    2008-01-01

    This article responds to Gray’s (2002) call for normative research on social and environmental accounting (SEA) and Parker’s (2005) call for active engagement in the process of designing SEA systems. More specifically, our investigation focuses on the study of boundary setting for triple bottom line (TBL) reporting, an issue that has been given more attention by practitioners than by researchers. The study reviews the consequences of boundary setting for the discharge of organizational accountability, from which it develops a framework to investigate TBL reporting boundaries and then reports on an empirical survey of best practice. It concludes that organizations are strategically setting and disclosing their boundaries instead of discharging their accountability and argues that such strategies have far-reaching consequences, because reporting boundaries are not only reflective of organizations but also have a constitutive role in their definition. A further consequence is that it calls into question the use of voluntary labeling, such as “in accordance” with Global Reporting Initiative; one implication being that further research into technical developments in TBL reporting could contribute to the discharge of organizational accountability.

  4. Near-bottom Multibeam Survey Capabilities in the US National Deep Submergence Facility (Invited)

    NASA Astrophysics Data System (ADS)

    Yoerger, D. R.; McCue, S. J.; Jason; Sentry Operations Groups

    2010-12-01

    The US National Deep Submergence Facility (NDSF) provides near-bottom multibeam mapping capabilities from the autonomous underwater vehicle Sentry and the remotely operated vehicle Jason. These vehicles can be used to depths of 4500 and 6500m respectively. Both vehicles are equipped with Reson 7125 400khz multibeam sonars as well as compatible navigation equipment (inertial navigation systems, doppler velocity logs, and acoustic navigation systems). These vehicles have produced maps of rugged Mid-Ocean Ridge terrain in the Galapagos Rift, natural oil and gas seeps off the coast of Southern California, deep coral sites in the Gulf of Mexico, and sites for the Ocean Observing Initiative off the coast of Oregon. Multibeam surveys are conducted from heights between 20 and 80 meters, allowing the scientific user to select the tradeoff between resolution and coverage rate. In addition to conventional bathymetric mapping, the systems have used to image methane bubble plumes from natural seeps. This talk will provide summaries of these mapping efforts and describe the data processing pipeline used to produce maps shortly after each dive. Development efforts to reduce navigational errors and reconcile discrepancies between adjacent swaths will also be described.

  5. Comparison between ROV video and Agassiz trawl methods for sampling deep water fauna of submarine canyons in the Northwestern Mediterranean Sea with observations on behavioural reactions of target species

    NASA Astrophysics Data System (ADS)

    Ayma, A.; Aguzzi, J.; Canals, M.; Lastras, G.; Bahamon, N.; Mecho, A.; Company, J. B.

    2016-08-01

    In this paper we present a comparison between Remotely Operated Vehicle (ROV) and Agassiz trawling methods for sampling deep-water fauna in three submarine canyons of the Northwestern Mediterranean Sea and describe the behavioural reactions of fishes and crustacean decapods to ROV approach. 10 ROV dives, where 3583 individuals were observed and identified to species level, and 8 Agassiz trawls were carried out in a depth range of 750-1500 m. As noticed in previous studies, abundances of fishes and decapod crustaceans were much higher in the ROV videos than in Agassiz trawl samples, as the latter are designed for the retrieval of benthic, less motile species in permanent contact with the bottom. In our observations fish abundance was one order of magnitude higher with ROV (4110.22 ind/km2) than with Agassiz trawl (350.88 ind/km2), whereas decapod crustaceans were six times more abundant in ROV videos (6362.40 ind/km2) than in Agassiz samples (1364.52 ind/km2). The behaviour of highly motile fishes was analysed in terms of stationary positioning over the seafloor and avoidance or attraction to ROV approach. The most frequently occurring fish species Coelorinchus mediterraneus, Nezumia aequalis, Bathypterois dubius, Lepidion lepidion, Trachyrincuss scabrus and Polyacanthonotus rissoanus did not react to the presence of the ROV in most cases (>50%). Only B. dubius (11%), Lepidion lepidion (14.8%), P. rissoanus (41%) and T. scabrus (14.3%) reacted to ROV approach. More than 60% of less motile species, such as crustacean decapods, did not respond to ROV presence either. Only 33.3% of Geryon longipes, 36.2% of Munida spp. and 29.79% of Pagurus spp. were observed avoiding or defensively reacting to the ROV. The comparison of results obtained with ROV and trawl sampling is of ecological relevance since ROV can report observations in areas where trawling is technically unfeasible. The lack of reaction by most fish and crustacean decapod specimens further confirms that ROV

  6. The role of juveniles in structuring demersal assemblages in trawled fishing grounds

    NASA Astrophysics Data System (ADS)

    Gristina, M.; Fiorentino, F.; Gancitano, V.; Massi, D.; Mirto, S.; Garofalo, G.

    2013-11-01

    The capture of large amounts of small, immature fish of commercial species is a serious problem particularly in multispecies fisheries. Moreover, considerable and increasing interest is being devoted by fishery scientists to identify the distribution and habitat needs of species throughout their life cycle. To elucidate species composition, the abundance of juveniles in the demersal assemblages and the role of different life history (juvenile and adult) stages of target species in structuring demersal communities, two bottom trawl surveys were carried out during the autumn 2003 and 2004. Multivariate analyses were performed on density indices of adults and juveniles life stages of 30 target species and total density indices for the remainder of the catch species. Juveniles represent more than 61% of the total catch in both the years investigated and their abundance and spatial distribution was strictly related to the sea bottom biocoenotic features. Most juveniles were concentrated in the coastal shelf area and in particular in the hauls performed on the Coastal Terrigenous Mud biocoenosis (CTM). The demersal assemblages located in the slope stratum showed, in general, a lower concentration of juvenile specimens; however, some facies of the Bathyal Mud biocoenosis that characterizes the deep layer of our study area showed a very high percentage of juveniles. This information improves our understanding of ecosystem functioning and represents a useful basis for providing advice on the management of multispecies demersal fisheries within an ecosystem approach.

  7. Initial Biotic Survey of Lisbon Bottom, Big Muddy National Fish and Wildlife Refuge

    USGS Publications Warehouse

    Humburg, Dale D.; Burke, Vincent J.

    1999-01-01

    The 2,300-acre Lisbon Bottom Unit, located in central Missouri, became part of the Big Muddy National Fish and Wildlife Refuge (NFWR) after the Great Flood of 1993 devastated the Unit?s farmland and network of levees. As a result, interdisciplinary studies were initiated through collaboration among various researches, universities, and State and Federal conservation agencies to investigate the short-term effects of the flood and to expand information about the Missouri River and flood-plain systems. The studies included in these chapters investigate diverse aspects of Lisbon Bottom Unit?s physical setting and biota and provide baseline information that managers can use to assess restoration efforts on Lisbon Bottom and other units of the Big Muddy NFWR.

  8. Effects of experimental otter trawling on benthic assemblages on Western Bank, northwest Atlantic Ocean

    NASA Astrophysics Data System (ADS)

    Kenchington, Ellen L. R.; Gilkinson, Kent D.; MacIsaac, Kevin G.; Bourbonnais-Boyce, Cynthia; Kenchington, Trevor J.; Smith, Stephen J.; Gordon, Donald C., Jr.

    2006-10-01

    The effects of otter trawling on a hard-bottom ecosystem on Western Bank on Canada's Scotian Shelf were examined experimentally from 1997 to 1999 with an asymmetrical BACI design. The site was located within an area that had been closed to fishing since 1987 to protect juvenile haddock. An experimental line was trawled 12-14 times on three separate occasions over a 20 month period. The benthic macrofauna and megafauna were sampled before and after trawling on both impact and control lines with both a grab and a photographic system. The 100 grab samples collected contained 341 taxa, primarily polychaetes, amphipods and molluscs, the majority (60%) of which were epifaunal. Biomass was dominated by the horse-mussel Modiolus modiolus, a long-lived bivalve, while the tube-building amphipod Ericthonius fasciatus was the most abundant species. Through the study period the benthos on the control lines showed little qualitative or quantitative change in individual taxa or community metrics. However, the abundance of 24 individual taxa (polychaetes, amphipods, echinoderms and molluscs) changed significantly, with the majority of these increasing. This resulted in a significantly different relative abundance of taxa between years as detected through ANOSIM. A significant change in relative biomass amongst the taxa was also observed. Trawling had few detectable immediate effects on the abundance or biomass of individual taxa and none on community composition. A few taxa, primarily a mixture of polychaetes and amphipods, decreased significantly after trawling and data from fish stomachs collected during the experiment (Kenchington, E.L., Gordon Jr., D.C., Bourbonnais-Boyce, C., MacIsaac, K.G., Gilkinson, K.D., McKeown, D.L., Vass, W.P., 2005. Effects of experimental otter trawling on the feeding of demersal fish on Western Bank, Nova Scotia. Amer. Fish. Soc. Symp. 41, 391-409) showed that some of these were scavenged by demersal fish. Fifteen taxa showed significant decreases

  9. Small trawls in juvenile flatfish research: Their development and efficiency

    NASA Astrophysics Data System (ADS)

    Kuipers, Bouwe R.; Maccurrin, B.; Miller, John M.; van der Veer, Henk W.; Witte, Johannes IJ.

    A resumé is given of the sampling techniques applied in juvenile flatfish research in the countries around the North Sea in the course of time with the emphasis on small trawl nets. A preliminary comparison of the relative efficiencies of otter-trawl and beam-trawl under different environmental conditions is presented. Beam-trawls show a higher and less variable efficiency than otter-trawls. The fixed width of a beam-trawl may be an important factor. Based on these results, a standardization of juvenile flatfish sampling techniques is suggested, based on the 1-m and 2-m beam-trawl.

  10. Trawling-induced alterations of deep-sea sediment accumulation rates during the Anthropocene

    NASA Astrophysics Data System (ADS)

    Puig, P.; Paradis, S.; Masque, P.; Martin, J.; Juan, X.; Palanques, A.

    2015-12-01

    Commercial bottom trawling causes direct physical disturbance of the marine sedimentary environments by scraping and ploughing the seabed, generating periodic resuspension of surface sediments. However, the quantification of the sediment that is removed by trawling and exported across the continental margin remains largely unaddressed, and the preservation of the signal of such impacts in the geological record have been mostly overlooked. The analysis of sediment cores collected along the Catalan margin (NW Mediterranean) has allowed evaluating the contribution of this anthropogenic activity to the present-day sediment dynamics. Sediment cores at intensively trawled sites are characterized by over-consolidated sediments with lower 210Pb surface concentrations and inventories that indicate widespread erosion of recent sedimentary deposits. In turn, combined 210Pb and 137Cs chronologies indicate a significant increase of sediment accumulation rates within submarine canyon environments since the 1970s, coincidently with a strong impulse in the industrialization of the trawling fleets of this region. Two sampling sites that exhibited high sediment accumulation rates (0.6-0.7 cm/y) were reoccupied 1-2 decades after the first studies and revealed a second and even larger increase of sediment accumulation rates (>2 cm/y) occurring at the beginning of the XXI century. This recent change has been attributed to a preferential displacement of the trawling fleet towards fishing grounds surrounding submarine canyons and, also, to technical improvements in trawling vessels, presumably related to financial subsidies provided to the fishing sector. The alteration of sediment accumulation rates described in this continental margin may occur in many regions of the World's oceans given the wide geographical distribution of this human activity, and therefore, it could represent a potential marker of the Anthropocene in deep-sea environments.

  11. An electric beam trawl for the capture of larval lampreys

    USGS Publications Warehouse

    McLain, Alberton; Dahl, Frederick H.

    1968-01-01

    The chemicals used to control the sea lamprey, Petromyzon marinus, in the Great Lakes have drastically reduced populations of larval lampreys in tributary streams. These larvicides are too costly and difficult to apply, however, in inland lakes, estuaries, and bays. Populations of sea lampreys in these areas constitute a threat to the refinement of the control. The gear available to locate, ample, and evaluate larval populations in deep water are inefficient. Electric shockers, satisfactory for collecting ammocoetes in streams, are limited to shallow water. The use of mechanical devices such as the Petersen dredge, anchor dredge, and the orange-peel dredge is time consuming, inefficient, and relatively ineffective in providing reliable quantitative evaluation of population size and composition over large areas of bottom. A device was required to sample adequately many areas in a short period of time, regardless of the depth of water. Mobility also was essential to permit operation of the unit in the various Great Lakes and in inland waters. An electrified beam trawl has been developed that most nearly meets these requirements. It has been used successfully to collect larvae of the sea lamprey, American brook lamprey (Lampetra lamottei), northern brook lamprey (Ichthyomyzon fossor), and silver lamprey (I. unicuspis). Effectiveness of the trawl did not appear to differ with species.

  12. The seascape of demersal fish nursery areas in the North Mediterranean Sea, a first step towards the implementation of spatial planning for trawl fisheries.

    PubMed

    Colloca, Francesco; Garofalo, Germana; Bitetto, Isabella; Facchini, Maria Teresa; Grati, Fabio; Martiradonna, Angela; Mastrantonio, Gianluca; Nikolioudakis, Nikolaos; Ordinas, Francesc; Scarcella, Giuseppe; Tserpes, George; Tugores, M Pilar; Valavanis, Vasilis; Carlucci, Roberto; Fiorentino, Fabio; Follesa, Maria C; Iglesias, Magdalena; Knittweis, Leyla; Lefkaditou, Eugenia; Lembo, Giuseppe; Manfredi, Chiara; Massutí, Enric; Pace, Marie Louise; Papadopoulou, Nadia; Sartor, Paolo; Smith, Christopher J; Spedicato, Maria Teresa

    2015-01-01

    The identification of nursery grounds and other essential fish habitats of exploited stocks is a key requirement for the development of spatial conservation planning aimed at reducing the adverse impact of fishing on the exploited populations and ecosystems. The reduction in juvenile mortality is particularly relevant in the Mediterranean and is considered as one of the main prerequisites for the future sustainability of trawl fisheries. The distribution of nursery areas of 11 important commercial species of demersal fish and shellfish was analysed in the European Union Mediterranean waters using time series of bottom trawl survey data with the aim of identifying the most persistent recruitment areas. A high interspecific spatial overlap between nursery areas was mainly found along the shelf break of many different sectors of the Northern Mediterranean indicating a high potential for the implementation of conservation measures. Overlap of the nursery grounds with existing spatial fisheries management measures and trawl fisheries restricted areas was also investigated. Spatial analyses revealed considerable variation depending on species and associated habitat/depth preferences with increased protection seen in coastal nurseries and minimal protection seen for deeper nurseries (e.g. Parapenaeus longirostris 6%). This is partly attributed to existing environmental policy instruments (e.g. Habitats Directive and Mediterranean Regulation EC 1967/2006) aiming at minimising impacts on coastal priority habitats such as seagrass, coralligenous and maerl beds. The new knowledge on the distribution and persistence of demersal nurseries provided in this study can support the application of spatial conservation measures, such as the designation of no-take Marine Protected Areas in EU Mediterranean waters and their inclusion in a conservation network. The establishment of no-take zones will be consistent with the objectives of the Common Fisheries Policy applying the ecosystem

  13. The Seascape of Demersal Fish Nursery Areas in the North Mediterranean Sea, a First Step Towards the Implementation of Spatial Planning for Trawl Fisheries

    PubMed Central

    Colloca, Francesco; Garofalo, Germana; Bitetto, Isabella; Facchini, Maria Teresa; Grati, Fabio; Martiradonna, Angela; Mastrantonio, Gianluca; Nikolioudakis, Nikolaos; Ordinas, Francesc; Scarcella, Giuseppe; Tserpes, George; Tugores, M. Pilar; Valavanis, Vasilis; Carlucci, Roberto; Fiorentino, Fabio; Follesa, Maria C.; Iglesias, Magdalena; Knittweis, Leyla; Lefkaditou, Eugenia; Lembo, Giuseppe; Manfredi, Chiara; Massutí, Enric; Pace, Marie Louise; Papadopoulou, Nadia; Sartor, Paolo; Smith, Christopher J.; Spedicato, Maria Teresa

    2015-01-01

    The identification of nursery grounds and other essential fish habitats of exploited stocks is a key requirement for the development of spatial conservation planning aimed at reducing the adverse impact of fishing on the exploited populations and ecosystems. The reduction in juvenile mortality is particularly relevant in the Mediterranean and is considered as one of the main prerequisites for the future sustainability of trawl fisheries. The distribution of nursery areas of 11 important commercial species of demersal fish and shellfish was analysed in the European Union Mediterranean waters using time series of bottom trawl survey data with the aim of identifying the most persistent recruitment areas. A high interspecific spatial overlap between nursery areas was mainly found along the shelf break of many different sectors of the Northern Mediterranean indicating a high potential for the implementation of conservation measures. Overlap of the nursery grounds with existing spatial fisheries management measures and trawl fisheries restricted areas was also investigated. Spatial analyses revealed considerable variation depending on species and associated habitat/depth preferences with increased protection seen in coastal nurseries and minimal protection seen for deeper nurseries (e.g. Parapenaeus longirostris 6%). This is partly attributed to existing environmental policy instruments (e.g. Habitats Directive and Mediterranean Regulation EC 1967/2006) aiming at minimising impacts on coastal priority habitats such as seagrass, coralligenous and maerl beds. The new knowledge on the distribution and persistence of demersal nurseries provided in this study can support the application of spatial conservation measures, such as the designation of no-take Marine Protected Areas in EU Mediterranean waters and their inclusion in a conservation network. The establishment of no-take zones will be consistent with the objectives of the Common Fisheries Policy applying the ecosystem

  14. High-resolution AUV-based near bottom magnetic surveys at Palinuro volcanic complex (Southern Tyrrhenian Sea)

    NASA Astrophysics Data System (ADS)

    Cocchi, L.; Plunkett, S.; Augustin, N.; Petersen, S.

    2013-12-01

    In this paper we present the preliminary results of new near bottom magnetic datasets collected during the recent POS442 cruise using the autonomous underwater vehicle (AUV) Abyss. The Southern Tyrrhenian basin is characterized by deep seafloor interspersed with huge volcanic seamounts (e.g Vavilov and Marsili and those associated to the Aeolian volcanic arc), which were formed during eastward roll back of the Apennine subduction system. These submarine edifices often are affected by significant hydrothermal activity and associated mineral deposits such as those observed at Marsili, Palinuro and Panarea. The western part of the Palinuro volcanic complex is characterized by a half rim of a caldera-like structure and hosts hydrothermal barite-pyrite deposits. Until recently, the full extent of the hydrothermal system remained poorly defined, as exploration has been limited to a few specific sites. In November 2012, a set of high resolution near seafloor geophysical surveys were carried out using GEOMAR's AUV Abyss to attempt to better define the hydrothermal mineralization at Palinuro. Five AUV dives were performed, mapping a total area of 3.7 km2 over the western part of Palinuro. Geomar's Abyss AUV (a Remus6000 class vehicle) was equipped with an Applied Physics Systems flux gate magnetometer, writing to a stand alone data logger, powered by the AUV's main batteries. The 5 dives were performed within the same area but with different primary geophysical sensors (multibeam, sidescan sonar, subbottom profiler), survey altitudes above seafloor (100m, 40m) and line spacing (150m, 100m, 20m). Magnetic data was collect on all five dives. At the beginning of each dive, the AUV performed a set of calibration manoeuvres, involving a 360 degree heading variation, a set of three upwards/downwards pitches, and three port and starboard yaws. This magnetic data reveals the magnetization features of the seafloor in unprecedented detail, highlighting a complex pattern mostly due to

  15. A synoptic survey of trace metals in bottom sediments of the Willamette River, Oregon

    USGS Publications Warehouse

    Rickert, David A.; Kennedy, V.C.; McKenzie, S.W.; Hines, W.G.

    1977-01-01

    For nearly half a century the Willamette River in Oregon experienced severe dissolved-oxygen problems related to large loads of organically rich waste waters from industries and municipalities. Since the mid-1950 's dissolved oxygen quality has gradually improved owing to low-flow augmentation, the achievement of basinwide secondary treatment, and the use of other waste-management practices. As a result, summer dissolved-oxygen levels have increased, salmon runs have returned, and the overall effort is widely regarded as a singular water-quality success. To document the improved dissolved-oxygen regimen, the U.S. Geological Survey conducted intensive studies of the Willamette during the summer low-flow seasons of 1973 and 1974. During each summer the mean daily dissolved-oxygen levels were found to be higher than 5 milligrams per liter throughout the river. Because of the basinwide secondary treatment, carbonaceous deoxygenation rates were low. In addition, almost half of the biochemical oxygen demand entering the Willamette was from diffuse (nonpoint) sources rather than outfalls. These results indicated that point-source biochemical oxygen demand was no longer the primary cause of dissolved-oxygen depletion. Instead, the major causes of deoxygenation were nitrification in a shallow ' surface active ' reach below Salem and an anomalous oxygen demand (believed to be primarily of benthal origin) in Portland Harbor. (Woodard-USGS)

  16. Evaluating ecosystem-based management options: Effects of trawling in Torres Strait, Australia

    NASA Astrophysics Data System (ADS)

    Ellis, Nick; Pantus, Francis; Welna, Andrzej; Butler, Alan

    2008-09-01

    A suite of management options for a prawn trawl fishery in Torres Strait, Australia was assessed for impacts on the benthic fauna using a dynamic management strategy evaluation approach. The specification of the management options was gained through consultation with stakeholders. Data for the model was drawn from several sources: the fleet data from fishery logbooks and satellite vessel monitoring systems, benthic depletion rates from trawl-down experiments, benthic recovery rates from post-experiment recovery monitoring studies, and benthic distribution from large-scale benthic surveys. Although there were large uncertainties in the resulting indicators, robust measures relevant to management were obtained by taking ratios relative to the status quo. The management control with the biggest effect was total effort; reducing trawl effort always led to increases in benthic faunal density of up to 10%. Spatial closures had a smaller benefit of up to 2%. The effect of closing a set of buffer zones around reefs to trawling was indistinguishable from the status quo option. Closing a larger area, however, was largely beneficial especially for sea cucumbers. When the spatial distributions of fauna prior to fishing were accounted for, fauna with distributions positively correlated with effort improved relative to those negatively correlated. The reduction in prawn catch under effort reduction scenarios could be ameliorated by introducing temporal closures over the full-moon period.

  17. Deep-sea crustacean trawling fisheries in Portugal: quantification of effort and assessment of landings per unit effort using a Vessel Monitoring System (VMS).

    PubMed

    Bueno-Pardo, Juan; Ramalho, Sofia P; García-Alegre, Ana; Morgado, Mariana; Vieira, Rui P; Cunha, Marina R; Queiroga, Henrique

    2017-01-18

    Mapping and quantifying bottom trawling fishing pressure on the seafloor is pivotal to understand its effects on deep-sea benthic habitats. Using data from the Vessel Monitoring System of crustacean trawlers along the Portuguese margin, we have identified the most exploited areas and characterized the most targeted habitats and water depths. We estimated a total trawling effort of 69596, 66766, and 63427 h y(-1) for the years 2012, 2013, and 2014 respectively which, considering the total landings estimated for this gear, yield values of 20.76, 21.06, and 19.11 kg of landed fish per trawled hour. The main trawling pressure is exerted in the South and Southwest Portuguese margins, on muddy and muddy-sand bottoms between 200 and 700 m water depths, while in the North and Central-West coasts a minor effort, at shallower waters and across a wider range of habitats, is also applied. The most landed species are crustaceans such as rose shrimp and Norway lobster, although this varies importantly between the different regions of Portugal, being fish and cephalopods the main captures in the Northern ports. We discuss the consequences of trawling for the impacted communities as well as the characteristics of the commercialization of these captures in Portugal.

  18. Deep-sea crustacean trawling fisheries in Portugal: quantification of effort and assessment of landings per unit effort using a Vessel Monitoring System (VMS)

    NASA Astrophysics Data System (ADS)

    Bueno-Pardo, Juan; Ramalho, Sofia P.; García-Alegre, Ana; Morgado, Mariana; Vieira, Rui P.; Cunha, Marina R.; Queiroga, Henrique

    2017-01-01

    Mapping and quantifying bottom trawling fishing pressure on the seafloor is pivotal to understand its effects on deep-sea benthic habitats. Using data from the Vessel Monitoring System of crustacean trawlers along the Portuguese margin, we have identified the most exploited areas and characterized the most targeted habitats and water depths. We estimated a total trawling effort of 69596, 66766, and 63427 h y‑1 for the years 2012, 2013, and 2014 respectively which, considering the total landings estimated for this gear, yield values of 20.76, 21.06, and 19.11 kg of landed fish per trawled hour. The main trawling pressure is exerted in the South and Southwest Portuguese margins, on muddy and muddy-sand bottoms between 200 and 700 m water depths, while in the North and Central-West coasts a minor effort, at shallower waters and across a wider range of habitats, is also applied. The most landed species are crustaceans such as rose shrimp and Norway lobster, although this varies importantly between the different regions of Portugal, being fish and cephalopods the main captures in the Northern ports. We discuss the consequences of trawling for the impacted communities as well as the characteristics of the commercialization of these captures in Portugal.

  19. Deep-sea crustacean trawling fisheries in Portugal: quantification of effort and assessment of landings per unit effort using a Vessel Monitoring System (VMS)

    PubMed Central

    Bueno-Pardo, Juan; Ramalho, Sofia P.; García-Alegre, Ana; Morgado, Mariana; Vieira, Rui P.; Cunha, Marina R.; Queiroga, Henrique

    2017-01-01

    Mapping and quantifying bottom trawling fishing pressure on the seafloor is pivotal to understand its effects on deep-sea benthic habitats. Using data from the Vessel Monitoring System of crustacean trawlers along the Portuguese margin, we have identified the most exploited areas and characterized the most targeted habitats and water depths. We estimated a total trawling effort of 69596, 66766, and 63427 h y−1 for the years 2012, 2013, and 2014 respectively which, considering the total landings estimated for this gear, yield values of 20.76, 21.06, and 19.11 kg of landed fish per trawled hour. The main trawling pressure is exerted in the South and Southwest Portuguese margins, on muddy and muddy-sand bottoms between 200 and 700 m water depths, while in the North and Central-West coasts a minor effort, at shallower waters and across a wider range of habitats, is also applied. The most landed species are crustaceans such as rose shrimp and Norway lobster, although this varies importantly between the different regions of Portugal, being fish and cephalopods the main captures in the Northern ports. We discuss the consequences of trawling for the impacted communities as well as the characteristics of the commercialization of these captures in Portugal. PMID:28098211

  20. Impact of natural (storm) and anthropogenic (trawling) sediment resuspension on particulate organic matter in coastal environments

    NASA Astrophysics Data System (ADS)

    Pusceddu, A.; Grémare, A.; Escoubeyrou, K.; Amouroux, J. M.; Fiordelmondo, C.; Danovaro, R.

    2005-12-01

    In order to assess the impact of natural and anthropogenic sediment resuspension on quantity, biochemical composition and bioavailability of particulate organic matter (POM), two field investigations were carried out in two shallow coastal areas of the Mediterranean Sea. In the Gulf of Lions, we investigated the impact of a storm resuspension of sediment, whereas in the Thermaikos Gulf we investigated the impact of bottom trawling. Resuspension in the Gulf of Lions determined the increase of sedimentation rates, modified the composition of the organic fraction of settling particles and decreased the labile fraction of POM, as indicated by a drop in the enzymatically hydrolysable amino acid fraction. The increase in the refractory fraction, following short-term storm-induced resuspension, increased also the contribution of glycine and decreased the contribution of aspartic acid contents to the total amino acid pools. Trawling activities in Thermaikos Gulf determined a significant increase in suspended POM concentrations and important changes in its biochemical composition. After trawling, the protein to carbohydrate ratio decreased (as a result of a major input of sedimentary carbohydrates at the water-sediment interface) and the fraction of enzymatically hydrolysable biopolymeric C decreased by ≈30%, thus reducing the bioavailability of resuspended organic particles. Results of the present study indicate that changes in suspended POM, induced by storms and trawling activities, can have similar consequences on benthic systems and on food webs. In fact, the potential benefit of increased organic particle concentration for suspension feeders, is depressed by the shift of suspended food particles towards a more refractory composition.

  1. Microplastic sampling with the AVANI trawl compared to two neuston trawls in the Bay of Bengal and South Pacific.

    PubMed

    Eriksen, Marcus; Liboiron, Max; Kiessling, Tim; Charron, Louis; Alling, Abigail; Lebreton, Laurent; Richards, Heather; Roth, Barent; Ory, Nicolas C; Hidalgo-Ruz, Valeria; Meerhoff, Erika; Box, Carolynn; Cummins, Anna; Thiel, Martin

    2017-09-28

    Many typical neuston trawls can only be used during relatively calm sea states and slow tow speeds. During two expeditions to the Bay of Bengal and the eastern South Pacific we investigated whether the new, high-speed AVANI trawl (All-purpose Velocity Accelerated Net Instrument) collects similar amounts and types of microplastics as two established scientific trawl designs, the manta trawl and the DiSalvo neuston net. Using a 335 μm net, the AVANI trawl can collect microplastics from the sea surface at speeds up to 8 knots as it "skis" across the surface, whereas the manta and DiSalvo neuston trawls must be towed slowly in a less turbulent sea state and often represent shorter tow lengths. Generally, the AVANI trawl collected a greater numerical abundance and weight of plastic particles in most size classes and debris types than the manta trawl and DiSalvo neuston net, likely because these trawls only skim the surface layer while the AVANI trawl, moving vertically in a random fashion, collects a "deeper" sample, capturing the few plastics that float slightly lower in the water column. However, the samples did not differ enough that results were significantly affected, suggesting that studies done with these different trawls are comparable. The advantage of the AVANI trawl over traditional research trawls is that it allows for collection on vessels underway at high speeds and during long transits, allowing for a nearly continuous sampling effort over long distances. As local surface currents make sea surface abundance widely heterogeneous, widely spaced short-tow trawls, such as the manta and DiSalvo trawls, can catch or miss hotspots or meso-scale variability of microplastic accumulations, whereas the AVANI trawl, if utilized for back-to-back tows of intermediate distances (5-10 km), can bridge variable wind conditions and debris concentrations potentially reducing variance and provide a greater resolution of spatial distribution. Copyright © 2017 Elsevier Ltd

  2. Biological and physical oceanographic observations pertaining to the trawl fishery in a region of persistent coastal upwelling

    NASA Technical Reports Server (NTRS)

    Howe, J. T.; Gibson, D. B.; Evans, T. O.; Breaker, L.; Wrigley, R. C.; Broenkow, W. W.

    1981-01-01

    An upwelling episode in the Point Sal region of the central California coast is examined by using data obtained by a data buoy. The episodes was interrupted by the abrupt abatement of the strong wind which promotes coastal upwelling. The mean hourly upwelling index is calculated to be higher than the 20 year mean monthly value. During 3 days of light wind commercial bottom trawl operations were possible. Shipboard estimates of chlorophyll content in surface waters during trawling show the high concentrations that are indicative of a rich biomass of phytoplankton, a result of the upwelling episode. Satellite imagery shows the extent of the upwelling water to be of the order of 100 km offshore; the result of many upwelling episodes. Shipboard echo sounder data show the presence of various delmersal species and of zooplakton; the latter graze on the phytoplankton in the upper euphotic layers. The fish catch data are recorded according to species for 2 days of trawling, and the catch per trawl hour is recorded.

  3. High Resolution Geophysical Survey of Western Long Island Sound Offshore New York: An Estuary Floor Shaped by Bottom Currents and Human Activity

    NASA Astrophysics Data System (ADS)

    Vargas, W.; Cormier, M.; McHugh, C.

    2009-05-01

    Western Long Island Sound near metropolitan New York averages 16m in water depth, with a few elongated depression up to 40 m deep. In June 2006, we surveyed the westernmost section of Long island Sound with the R/V HUGH SHARP. Analysis of the high-resolution multibeam bathymetric data collected during that survey reveals a series of sedimentary features that are consistent with a net westward direction of bottom currents. These features include: (1) Large sedimentary waves spaced ab out 100 m west of two km-scale features outcropping through the sediments; (2) Prominent sediment drifts or scour marks west of numerous shipwrecks and bouldery outcrops; (3) Series of subtle, sub-parallel sedimentary furrows aligned in a general EW direction along the north slope of the surveyed area (similar features have been documented in north- central Long Island Sound - (Poppe et al., J. Coastal Res. 2002). The lack of short wavelength sedimentary waves is consistent with the known muddy substrate and weak bottom currents (<10 cm/s) documented in western Long Island Sound. Fields of pockmarks affecting areas of gas-charged sediments may indicate localized, active venting of fluids and/or gas. The high-resolution bathymetry also highlights numerous anthropogenic disturbances such as pipelines, cables, shipwrecks, anchor drag marks, and dredge spoils.

  4. Deep vision: an in-trawl stereo camera makes a step forward in monitoring the pelagic community.

    PubMed

    Underwood, Melanie J; Rosen, Shale; Engås, Arill; Eriksen, Elena

    2014-01-01

    Ecosystem surveys are carried out annually in the Barents Sea by Russia and Norway to monitor the spatial distribution of ecosystem components and to study population dynamics. One component of the survey is mapping the upper pelagic zone using a trawl towed at several depths. However, the current technique with a single codend does not provide fine-scale spatial data needed to directly study species overlaps. An in-trawl camera system, Deep Vision, was mounted in front of the codend in order to acquire continuous images of all organisms passing. It was possible to identify and quantify of most young-of-the-year fish (e.g. Gadus morhua, Boreogadus saida and Reinhardtius hippoglossoides) and zooplankton, including Ctenophora, which are usually damaged in the codend. The system showed potential for measuring the length of small organisms and also recorded the vertical and horizontal positions where individuals were imaged. Young-of-the-year fish were difficult to identify when passing the camera at maximum range and to quantify during high densities. In addition, a large number of fish with damaged opercula were observed passing the Deep Vision camera during heaving; suggesting individuals had become entangled in meshes farther forward in the trawl. This indicates that unknown numbers of fish are probably lost in forward sections of the trawl and that the heaving procedure may influence the number of fish entering the codend, with implications for abundance indices and understanding population dynamics. This study suggests modifications to the Deep Vision and the trawl to increase our understanding of the population dynamics.

  5. Deep Vision: An In-Trawl Stereo Camera Makes a Step Forward in Monitoring the Pelagic Community

    PubMed Central

    Underwood, Melanie J.; Rosen, Shale; Engås, Arill; Eriksen, Elena

    2014-01-01

    Ecosystem surveys are carried out annually in the Barents Sea by Russia and Norway to monitor the spatial distribution of ecosystem components and to study population dynamics. One component of the survey is mapping the upper pelagic zone using a trawl towed at several depths. However, the current technique with a single codend does not provide fine-scale spatial data needed to directly study species overlaps. An in-trawl camera system, Deep Vision, was mounted in front of the codend in order to acquire continuous images of all organisms passing. It was possible to identify and quantify of most young-of-the-year fish (e.g. Gadus morhua, Boreogadus saida and Reinhardtius hippoglossoides) and zooplankton, including Ctenophora, which are usually damaged in the codend. The system showed potential for measuring the length of small organisms and also recorded the vertical and horizontal positions where individuals were imaged. Young-of-the-year fish were difficult to identify when passing the camera at maximum range and to quantify during high densities. In addition, a large number of fish with damaged opercula were observed passing the Deep Vision camera during heaving; suggesting individuals had become entangled in meshes farther forward in the trawl. This indicates that unknown numbers of fish are probably lost in forward sections of the trawl and that the heaving procedure may influence the number of fish entering the codend, with implications for abundance indices and understanding population dynamics. This study suggests modifications to the Deep Vision and the trawl to increase our understanding of the population dynamics. PMID:25393121

  6. [Determination of stress in fish community obtained from shrimp trawl fishing in Northern Gulf of California].

    PubMed

    Herrera-Valdivia, Eloísa; López-Martínez, Juana; Vargasmachuca, Sergio Castillo

    2015-09-01

    Bottom trawling has been considered a fishing activity that affects and modifies habitats, because of its impacts in species composition and abundance, and the alteration in the structure and function of the eco-system, that generates biodiversity loss. The Northern part of the Gulf of California has been considered a mega diverse zone with high endemism, and it is of growing interest by the international scientific community. In order to assess its potential changes in the fish community components of shrimp by-catch (FAC) in this area, a total of 119 trawls from 13 fishing boats were analyzed in Puerto Peñasco, based on 14 commercial fishing trips made within 9-90 m depth from 2010-2011. A random sample of 20 kg was obtained from each trawl, and was analyzed in the laboratory for species composition. In addition to the Index of Biological Value (IVB), Shannon diversity (H'), and Pielou evenness (J'), comparative abundance-biomass curves (ABC) were also estimated. Eucinostomus dowii showed the highest IVB = 480.25; Porichthys analis showed greater relative abundance; and Pomadasys panamensis showed greater frequency of occurrence. The mean monthly values in diversity H' = 3.05 (2.72 > H' < 3.25) and J' = 0.71 (0.66 < J' >0.81) showed a tendency to decrease as the fishing season progressed. The comparative abundance-biomass curves (ABC), and the value of statistical W showed moderate stress levels in March (W= -0.022) and September (W= -0.02) 2010, and January 2011 (W= -0.042). In conclusion, the Northern Gulf of California showed a well-structured community with a degree of moderate fishing stress.

  7. Process-driven and biological characterisation and mapping of seabed habitats sensitive to trawling.

    PubMed

    Foveau, Aurélie; Vaz, Sandrine; Desroy, Nicolas; Kostylev, Vladimir E

    2017-01-01

    The increase of anthropogenic pressures on the marine environment together with the necessity of a sustainable management of marine living resources have underlined the need to map and model coastal environments, particularly for the purposes of spatial planning and for the implementation of integrated ecosystem-based management approach. The present study compares outputs of a process-driven benthic habitat sensitivity (PDS) model to the structure, composition and distribution of benthic invertebrates in the Eastern English Channel and southern part of the North Sea. Trawl disturbance indicators (TDI) computed from species biological traits and benthic community composition were produced from samples collected with a bottom trawl. The TDI was found to be highly correlated to the PDS further validating the latter's purpose to identify natural process-driven pattern of sensitivity. PDS was found to reflect an environmental potential that may no longer be fully observable in the field and difference with in situ biological observations could be partially explained by the spatial distribution of fishery pressure on the seafloor. The management implication of these findings are discussed and we suggest that, used in conjunction with TDI approaches, PDS may help monitor management effort by evaluating the difference between the current state and the presumed optimal environmental status of marine benthic habitats.

  8. 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.

  9. Recovery of Seamount Precious Coral Beds From Heavy Trawling Disturbance

    NASA Astrophysics Data System (ADS)

    Morgan, N.; Baco-Taylor, A.; Roark, B.

    2016-02-01

    Resilience and the related concept of recovery provide insights into ecosystem function, connectivity, and succession. Most marine resilience studies have focused on shallow-water ecosystems. However, increasing anthropogenic impacts in the deep sea make studies of resilience and recovery in the deep sea time-critical, with deep-sea hard-substrate habitats and large-scale disturbances having received the least attention. Ironically one of the key anthropogenic impacts to the seafloor, trawling, provides an ideal experimental design to understand processes of recovery from large-scale disturbance in the deep sea. Seamount hard-substrate habitats in particular are thought to have low resilience due to the slow growth rates and recruitment limitations of key structure-forming taxa. The goal of our project is to test the hypothesis of low resilience by examining a series of locations in the far Northwestern Hawaiian Islands and the Emperor Seamount Chain. These sites have had some of the heaviest trawl impacts in the world, from both fish and precious coral fisheries, and include sites that are still trawled as well as ones that have been protected since the establishment of the US Exclusive Economic Zone in 1977. We compare these to untrawled sites as part of a three "treatment" design. During two cruises in 2014 and 2015 we used the AUV Sentry to image nine features (three per treatment). CTD data were also collected. Images were analyzed for all visible megafauna as well as substrate parameters (rugosity, slope, composition, relief). Yuryaku, in the "still trawled" treatment was characterized by extensive areas of bare substrate with abundant trawl scars. This feature also had lower diversity and lower abundance of megafauna compared to the recovering and never trawled locations. Preliminary data suggest recovering and never trawled features have overlapping species, but not in comparable abundances.

  10. 75 FR 7403 - Fisheries of the Exclusive Economic Zone Off Alaska; Bering Sea and Aleutian Islands Trawl...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-02-19

    ... Aleutian Islands (BSAI) trawl limited access fisheries, except American Fisheries Act (AFA) vessels using... for vessels participating in the BSAI trawl limited access fishery, except American Fisheries Act...

  11. Indexing the relative abundance of age-0 white sturgeons in an impoundment of the lower Columbia River from highly skewed trawling data

    USGS Publications Warehouse

    Counihan, T.D.; Miller, Allen I.; Parsley, M.J.

    1999-01-01

    The development of recruitment monitoring programs for age-0 white sturgeons Acipenser transmontanus is complicated by the statistical properties of catch-per-unit-effort (CPUE) data. We found that age-0 CPUE distributions from bottom trawl surveys violated assumptions of statistical procedures based on normal probability theory. Further, no single data transformation uniformly satisfied these assumptions because CPUE distribution properties varied with the sample mean (??(CPUE)). Given these analytic problems, we propose that an additional index of age-0 white sturgeon relative abundance, the proportion of positive tows (Ep), be used to estimate sample sizes before conducting age-0 recruitment surveys and to evaluate statistical hypothesis tests comparing the relative abundance of age-0 white sturgeons among years. Monte Carlo simulations indicated that Ep was consistently more precise than ??(CPUE), and because Ep is binomially rather than normally distributed, surveys can be planned and analyzed without violating the assumptions of procedures based on normal probability theory. However, we show that Ep may underestimate changes in relative abundance at high levels and confound our ability to quantify responses to management actions if relative abundance is consistently high. If data suggest that most samples will contain age-0 white sturgeons, estimators of relative abundance other than Ep should be considered. Because Ep may also obscure correlations to climatic and hydrologic variables if high abundance levels are present in time series data, we recommend ??(CPUE) be used to describe relations to environmental variables. The use of both Ep and ??(CPUE) will facilitate the evaluation of hypothesis tests comparing relative abundance levels and correlations to variables affecting age-0 recruitment. Estimated sample sizes for surveys should therefore be based on detecting predetermined differences in Ep, but data necessary to calculate ??(CPUE) should also be

  12. Effects of trawl selectivity and genetic parameters on fish body length under long-term trawling

    NASA Astrophysics Data System (ADS)

    Yu, Yang; Sun, Peng; Cui, He; Sheng, Huaxiang; Zhao, Fenfang; Tang, Yanli; Chen, Zelin

    2015-10-01

    Long-term fishing pressure affects the biological characteristics of exploited fish stocks. The biological characteristics of hairtail ( Trichiurus lepturus) in the East China Sea are unable to recover because of long-term trawling. Fishing induces evolutionary effects on the fish's biological characteristics. Evidence of these changes includes small size at age, a shift to earlier age structure, and early maturation. Natural and artificial selection usually affect the fish's life history. Selection can induce different chances of reproduction, and individual fish can give a different genetic contribution to the next generation. In this study, analysis of time-dependent probability of significance and test of sensitivity were used to explore the effects of fish exploitation rate, mesh size, and heritability with long-term trawling. Results showed that fishing parameters were important drivers to exploited fish population. However, genetic traits altered by fishing were slow, and the changes in biological characteristics were weaker than those caused by fishing selection. Exploitation rate and mesh size exhibited similar evolutionary trend tendency under long-term fishing. The time-dependent probability of significance trend showed a gradual growth and tended to be stable. Therefore, the direction of fishing-induced evolution and successful management of fish species require considerable attention to contribute to sustainable fisheries in China.

  13. Size Selection of Antarctic Krill (Euphausia superba) in Trawls

    PubMed Central

    Krag, Ludvig A.; Herrmann, Bent; Iversen, Svein A.; Engås, Arill; Nordrum, Sigve; Krafft, Bjørn A.

    2014-01-01

    Trawlers involved in the Antarctic krill (Euphausia superba) fishery use different trawl designs, and very little is known about the size selectivity of the various gears. Size selectivity quantifies a given trawl's ability to catch different sizes of a harvested entity, and this information is crucial for the management of a sustainable fishery. We established a morphological description of krill and used it in a mathematical model (FISHSELECT) to predict the selective potential of diamond meshes measuring 5–40 mm with mesh opening angles (oa) ranging from 10 to 90°. We expected the majority of krill to encounter the trawl netting in random orientations due to high towing speeds and the assumed swimming capabilities of krill. However, our results indicated that size selectivity of krill is a well-defined process in which individuals encounter meshes at an optimal orientation for escapement. The simulation-based results were supported by data from experimental trawl hauls and underwater video images of the mesh geometry during fishing. Herein we present predictions for the size selectivity of a range of netting configurations relevant to the krill fishery. The methods developed and results described are important tools for selecting optimal trawl designs for krill fishing. PMID:25105960

  14. Size selection of Antarctic krill (Euphausia superba) in trawls.

    PubMed

    Krag, Ludvig A; Herrmann, Bent; Iversen, Svein A; Engås, Arill; Nordrum, Sigve; Krafft, Bjørn A

    2014-01-01

    Trawlers involved in the Antarctic krill (Euphausia superba) fishery use different trawl designs, and very little is known about the size selectivity of the various gears. Size selectivity quantifies a given trawl's ability to catch different sizes of a harvested entity, and this information is crucial for the management of a sustainable fishery. We established a morphological description of krill and used it in a mathematical model (FISHSELECT) to predict the selective potential of diamond meshes measuring 5-40 mm with mesh opening angles (oa) ranging from 10 to 90°. We expected the majority of krill to encounter the trawl netting in random orientations due to high towing speeds and the assumed swimming capabilities of krill. However, our results indicated that size selectivity of krill is a well-defined process in which individuals encounter meshes at an optimal orientation for escapement. The simulation-based results were supported by data from experimental trawl hauls and underwater video images of the mesh geometry during fishing. Herein we present predictions for the size selectivity of a range of netting configurations relevant to the krill fishery. The methods developed and results described are important tools for selecting optimal trawl designs for krill fishing.

  15. Bottom production

    SciTech Connect

    Baines, J.; Baranov, S.P.; Bartalini, P.; Bay, A.; Bouhova, E.; Cacciari, M.; Caner, A.; Coadou, Y.; Corti, G.; Damet, J.; Dell-Orso, R.; De Mello Neto, J.R.T.; Domenech, J.L.; Drollinger, V.; Eerola, P.; Ellis, N.; Epp, B.; Frixione, S.; Gadomski, S.; Gavrilenko, I.; Gennai, S.; George, S.; Ghete, V.M.; Guy, L.; Hasegawa, Y.; Iengo, P.; Jacholkowska, A.; Jones, R.; Kharchilava, A.; Kneringer, E.; Koppenburg, P.; Korsmo, H.; Kramer, M.; Labanca, N.; Lehto, M.; Maltoni, F.; Mangano, M.L.; Mele, S.; Nairz, A.M.; Nakada, T.; Nikitin, N.; Nisati, A.; Norrbin, E.; Palla, F.; Rizatdinova, F.; Robins, S.; Rousseau, D.; Sanchis-Lozano, M.A.; Shapiro, M.; Sherwood, P.; Smirnova, L.; Smizanska, M.; Starodumov, A.; Stepanov, N.; Vogt, R.

    2000-03-15

    In the context of the LHC experiments, the physics of bottom flavoured hadrons enters in different contexts. It can be used for QCD tests, it affects the possibilities of B decays studies, and it is an important source of background for several processes of interest. The physics of b production at hadron colliders has a rather long story, dating back to its first observation in the UA1 experiment. Subsequently, b production has been studied at the Tevatron. Besides the transverse momentum spectrum of a single b, it has also become possible, in recent time, to study correlations in the production characteristics of the b and the b. At the LHC new opportunities will be offered by the high statistics and the high energy reach. One expects to be able to study the transverse momentum spectrum at higher transverse momenta, and also to exploit the large statistics to perform more accurate studies of correlations.

  16. 75 FR 13081 - Fisheries off West Coast States; Pacific Coast Groundfish Fishery; Trawl Rationalization Program

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-03-18

    ... National Oceanic and Atmospheric Administration RIN 0648-XRO1 Fisheries off West Coast States; Pacific Coast Groundfish Fishery; Trawl Rationalization Program AGENCY: National Marine Fisheries Service (NMFS... trawl rationalization program that would affect the limited entry trawl fishery of the Pacific...

  17. 50 CFR Figure 26 to Part 679 - Modified Nonpelagic Trawl Gear

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 50 Wildlife and Fisheries 13 2014-10-01 2014-10-01 false Modified Nonpelagic Trawl Gear 26 Figure... ALASKA Pt. 679, Fig. 26 Figure 26 to Part 679—Modified Nonpelagic Trawl Gear This figure shows the location of elevating devices in the elevated section of modified nonpelagic trawl gear, as specified...

  18. 50 CFR 660.114 - Trawl fishery-economic data collection program.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 50 Wildlife and Fisheries 13 2014-10-01 2014-10-01 false Trawl fishery-economic data collection... West Coast Groundfish-Limited Entry Trawl Fisheries § 660.114 Trawl fishery—economic data collection... 2009 through 2010. (b) Economic data collection program requirements. The following...

  19. 50 CFR 660.114 - Trawl fishery-economic data collection program.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 50 Wildlife and Fisheries 11 2011-10-01 2011-10-01 false Trawl fishery-economic data collection... West Coast Groundfish-Limited Entry Trawl Fisheries § 660.114 Trawl fishery—economic data collection program. (a) General. The economic data collection (EDC) program collects mandatory economic data from...

  20. Comparison of anchovy biomass estimates measured by trawls, egg production methods and hydro-acoustics in the Chesapeake Bay and the Korea Strait

    NASA Astrophysics Data System (ADS)

    Jung, Sukgeun; Houde, Edward D.

    2014-06-01

    We compared estimates of anchovy biomass derived from trawl surveys, egg production method (EPM) and acoustic surveys, conducted in two remote regions. Biomass density of bay anchovy Anchoa mitchilli was estimated in Chesapeake Bay, USA, by trawls, EPM and acoustics from 1989 to 2000. Biomass density of Pacific anchovy Engraulis japonicus was estimated in the Korea Strait using EPM, simulation-based daily cohort analysis and acoustics from 1984 to 2006. Most of the existing estimates already had considered body-size-dependent gear selectivity, highlyvariable instantaneous natural mortality of anchovy eggs, and avoidance of trawl nets by adult anchovy. Despite great variability in the ratio of trawl to acoustic biomass estimates (0.034-8.35), annually-averaged biomass density of young-ofthe-year individuals derived by the two methods were similar for bay anchovy in Chesapeake Bay and Pacific anchovy in the Korea Strait (0.83 and 0.70 g m-3, respectively). Results suggested that, despite substantial uncertainty, anchovy biomass estimates are generally compatible between EPM and acoustics. However, reported estimates of biomass density derived from the two acoustic surveys in the Korea Strait differed by a factor of 28, suggesting that further improvements in calibrations are required to reliably estimate anchovy biomass. The comparisons suggested that all biomass estimates could be biased and will require comparison and validation by other, independent sampling methods.

  1. Preliminary Results of a Near-Bottom Integrated Seafloor and Water Column survey of Brothers volcano, Kermadec arc, Using the Autonomous Vehicle ABE

    NASA Astrophysics Data System (ADS)

    Embley, R. W.; de Ronde, C.; Davy, B.; Baker, E. T.; Resing, J. A.; Yoerger, D. R.; Merle, S. G.; Walker, S. L.

    2007-12-01

    Brothers volcano, located about 310 km NE of New Zealand along the magmatic front of the Kermadec arc, is one of the best studied intraoceanic arc submarine volcanoes. Its 3.0 x 3.5 km caldera is slightly elliptical, with the long axis oriented about N320°E and has more than 300 m relief from a rim at ~1500 m to a maximum depth of 1880 m in its NW corner. Two major hydrothermal systems were discovered on it in the late 1990s, a high temperature field (up to 302°C) on the NW wall and a lower temperature gas-rich system on the summits of a pair of dacitic cones that occupy the SE half of the caldera. Although the caldera and cones were partly explored by submersibles in 2004 and 2005, the base map, made with a surface ship multibeam, was not detailed enough to understand the context of the seafloor observations. We used the autonomous vehicle ABE launched and recovered from the R/V SONNE in July-August 2007 to conduct high resolution near-bottom surveys of the caldera and its hydrothermal systems using a multibeam sonar, magnetometer, and CTD. The caldera wall, the dacite cones and part of the flat caldera rim were mapped in 96 hours of survey time over 8 dives. In addition, very detailed water column surveys at lower altitude and closer line spacing were conducted over the two most intense hydrothermal sites (i.e., the NW caldera wall and the smaller dacite cone). Although the results are preliminary, there are obvious correlations between hydrothermal activity, wall geomorphology, structural lineations, and the magnetic signature. New hydrothermal sites were discovered on the uppermost NW rim of the caldera and on the SW wall. This new map, along with the previously collected suites of fluid, mineral and seafloor observations, provides a baseline for future monitoring of Brothers' hydrothermal and volcanic activity. It will also provide a better understanding of how the long-term interplay of hydrothermal and volcanic activity affects the geomorphic evolution of

  2. 50 CFR 622.25 - Exemptions for Gulf groundfish trawling.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... ATLANTIC Reef Fish Resources of the Gulf of Mexico § 622.25 Exemptions for Gulf groundfish trawling. Gulf... requirements and limitations for the vessel's unsorted catch of Gulf reef fish: (1) The requirement for a valid commercial vessel permit for Gulf reef fish in order to sell Gulf reef fish. (2) Minimum size limits for Gulf...

  3. 50 CFR 654.23 - Southwest Florida seasonal trawl closure.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 50 Wildlife and Fisheries 10 2011-10-01 2011-10-01 false Southwest Florida seasonal trawl closure. 654.23 Section 654.23 Wildlife and Fisheries FISHERY CONSERVATION AND MANAGEMENT, NATIONAL OCEANIC AND ATMOSPHERIC ADMINISTRATION, DEPARTMENT OF COMMERCE STONE CRAB FISHERY OF THE GULF OF MEXICO Management...

  4. 50 CFR 660.120 - Trawl fishery-crossover provisions.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 50 Wildlife and Fisheries 9 2010-10-01 2010-10-01 false Trawl fishery-crossover provisions. 660.120 Section 660.120 Wildlife and Fisheries FISHERY CONSERVATION AND MANAGEMENT, NATIONAL OCEANIC AND ATMOSPHERIC ADMINISTRATION, DEPARTMENT OF COMMERCE (CONTINUED) FISHERIES OFF WEST COAST STATES West...

  5. Job Satisfaction in the Shrimp Trawl Fisheries of Chennai, India

    ERIC Educational Resources Information Center

    Bavinck, Maarten

    2012-01-01

    Shrimp trawling represents an important fishing metier in South India, generating high levels of employment and economic value. It is also a contested metier, ostensibly contributing to environmental degradation and social inequality. This paper investigates the job satisfaction of crew members (captains and workers) on board the shrimp trawlers…

  6. 77 FR 29586 - Sea Turtle Conservation; Shrimp Trawling Requirements; Correction

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-05-18

    ... [Federal Register Volume 77, Number 97 (Friday, May 18, 2012)] [Proposed Rules] [Pages 29586-29587] [FR Doc No: 2012-12013] DEPARTMENT OF COMMERCE National Oceanic and Atmospheric Administration 50 CFR Part 223 RIN 0648-BC10 Sea Turtle Conservation; Shrimp Trawling Requirements; Correction AGENCY...

  7. Job Satisfaction in the Shrimp Trawl Fisheries of Vietnam

    ERIC Educational Resources Information Center

    Sinh, Le Xuan

    2012-01-01

    This paper investigates the job satisfaction of small-scale shrimp trawl fishers in the vicinity of Camau National Park in southern Vietnam. The research sample consisted of 77 fishers who belong to a growing population of shrimp fishers in the region. The results suggest that 60% would change their fishing metier, 78% would leave fishing for…

  8. Job Satisfaction in the Shrimp Trawl Fisheries of Chennai, India

    ERIC Educational Resources Information Center

    Bavinck, Maarten

    2012-01-01

    Shrimp trawling represents an important fishing metier in South India, generating high levels of employment and economic value. It is also a contested metier, ostensibly contributing to environmental degradation and social inequality. This paper investigates the job satisfaction of crew members (captains and workers) on board the shrimp trawlers…

  9. Job Satisfaction in the Shrimp Trawl Fisheries of Vietnam

    ERIC Educational Resources Information Center

    Sinh, Le Xuan

    2012-01-01

    This paper investigates the job satisfaction of small-scale shrimp trawl fishers in the vicinity of Camau National Park in southern Vietnam. The research sample consisted of 77 fishers who belong to a growing population of shrimp fishers in the region. The results suggest that 60% would change their fishing metier, 78% would leave fishing for…

  10. 50 CFR 622.47 - Gulf groundfish trawl fishery.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... closure. (b) Other provisions of this part notwithstanding, a dealer in a Gulf state is exempt from the... 50 Wildlife and Fisheries 8 2010-10-01 2010-10-01 false Gulf groundfish trawl fishery. 622.47... ATMOSPHERIC ADMINISTRATION, DEPARTMENT OF COMMERCE FISHERIES OF THE CARIBBEAN, GULF, AND SOUTH...

  11. Benchmarking Non-Hardware Balance-of-System (Soft) Costs for U.S. Photovoltaic Systems Using a Bottom-Up Approach and Installer Survey

    SciTech Connect

    Ardani, Kristen; Margolis, Robert; Feldman, David; Ong, Sean; Barbose, Galen; Wiser, Ryan

    2012-11-01

    This report presents results from the first U.S. Department of Energy (DOE) sponsored, bottom-up data-collection and analysis of non-hardware balance-of-system costs—often referred to as “business process” or “soft” costs—for residential and commercial photovoltaic (PV) systems. Annual expenditure and labor-hour-productivity data are analyzed to benchmark 2010 soft costs related to the DOE priority areas of (1) customer acquisition; (2) permitting, inspection, and interconnection; (3) installation labor; and (4) installer labor for arranging third-party financing. Annual expenditure and labor-hour data were collected from 87 PV installers. After eliminating outliers, the survey sample consists of 75 installers, representing approximately 13% of all residential PV installations and 4% of all commercial installations added in 2010. Including assumed permitting fees, in 2010 the average soft costs benchmarked in this analysis total $1.50/W for residential systems (ranging from $0.66/W to $1.66/W between the 20th and 80th percentiles). For commercial systems, the median 2010 benchmarked soft costs (including assumed permitting fees) are $0.99/W for systems smaller than 250 kW (ranging from $0.51/W to $1.45/W between the 20th and 80th percentiles) and $0.25/W for systems larger than 250 kW (ranging from $0.17/W to $0.78/W between the 20th and 80th percentiles). Additional soft costs not benchmarked in the present analysis (e.g., installer profit, overhead, financing, and contracting) are significant and would add to these figures. The survey results provide a benchmark for measuring—and helping to accelerate—progress over the next decade toward achieving the DOE SunShot Initiative’s soft-cost-reduction targets. We conclude that the selected non-hardware business processes add considerable cost to U.S. PV systems, constituting 23% of residential PV system price, 17% of small commercial system price, and 5% of large commercial system price (in 2010

  12. Bottom Reflection Coefficient.

    DTIC Science & Technology

    SONAR SIGNALS, *UNDERWATER SOUND SIGNALS, SOUND TRANSMISSION, ACOUSTIC ATTENUATION, REVERBERATION, TRANSMISSION LOSS, ACOUSTIC REFLECTION, SOUND RANGING, BOTTOM LOSS, DEEP SCATTERING LAYERS, BOTTOM BOUNCE .

  13. Energy direct inputs and greenhouse gas emissions of the main industrial trawl fishery of Brazil.

    PubMed

    Port, Dagoberto; Perez, Jose Angel Alvarez; de Menezes, João Thadeu

    2014-11-15

    This study provides first-time estimates of direct fuel inputs and greenhouse gas emissions produced by the trawl fishing fleet operating off southeastern and southern Brazil. Analyzed data comprised vessel characteristics, landings, fishing areas and trawling duration of 10,144 fishing operations monitored in Santa Catarina State from 2003 to 2011. Three main fishing strategies were differentiated: 'shrimp trawling', 'slope trawling' and 'pair trawling'. Jointly these operations burned over 9.1 million liters of diesel to land 342.3 million kilograms of fish and shellfish. Annually, 0.023-0.031 l were consumed for every kg of catch landed. Because all fishing strategies relied on multispecific catches to raise total incomes, estimates of fuel use intensity were generally low but increased 200-900% if only nominal targets were considered. In nine years, trawling operations emitted 6.69 GgC to the atmosphere, between 2300 and 3300 tons CO2 per year.

  14. Job Satisfaction in the Shrimp Trawl Fisheries of Chennai, India.

    PubMed

    Bavinck, Maarten

    2012-10-01

    Shrimp trawling represents an important fishing métier in South India, generating high levels of employment and economic value. It is also a contested métier, ostensibly contributing to environmental degradation and social inequality. This paper investigates the job satisfaction of crew members (captains and workers) on board the shrimp trawlers of Chennai (former Madras). Research took place in 2007 and 2008 (N = 137). Results suggest a general satisfaction with being in the fishery. However, a little over three-fifths of fishers said they would be willing to change fishing métier and about one-half said they would leave the occupation. About one-half also said they would not advise a young person to enter the occupation. The tendency to move away from the fishery is argued to reflect a growing pessimism about the future of the shrimp trawl fisheries, but also an increasing awareness of other economic opportunities.

  15. Relationship between mid-water trawling effort and catch composition uncertainty in two large lakes (Huron and Michigan) dominated by alosines, osmerids, and coregonines

    USGS Publications Warehouse

    Warner, David M.; Claramunt, Randall M.; Schaeffer, Jeffrey S.; Yule, Daniel L.; Hrabik, Tom R.; Peintka, Bernie; Rudstam, Lars G.; Holuszko, Jeffrey D.; O'Brien, Timothy P.

    2012-01-01

    Because it is not possible to identify species with echosounders alone, trawling is widely used as a method for collecting species and size composition data for allocating acoustic fish density estimates to species or size groups. In the Laurentian Great Lakes, data from midwater trawls are commonly used for such allocations. However, there are no rules for how much midwater trawling effort is required to adequately describe species and size composition of the pelagic fish communities in these lakes, so the balance between acoustic sampling effort and trawling effort has been unguided. We used midwater trawl data collected between 1986 and 2008 in lakes Michigan and Huron and a variety of analytical techniques to develop guidance for appropriate levels of trawl effort. We used multivariate regression trees and re-sampling techniques to i. identify factors that influence species and size composition of the pelagic fish communities in these lakes, ii. identify stratification schemes for the two lakes, iii. determine if there was a relationship between uncertainty in catch composition and the number of tows made, and iv. predict the number of tows required to reach desired uncertainty targets. We found that depth occupied by fish below the surface was the most influential explanatory variable. Catch composition varied between lakes at depths <38.5 m below the surface, but not at depths ≥38.5 m below the surface. Year, latitude, and bottom depth influenced catch composition in the near-surface waters of Lake Michigan, while only year was important for Lake Huron surface waters. There was an inverse relationship between RSE [relative standard error = 100 × (SE/mean)] and the number of tows made for the proportions of the different size and species groups. We found for the fifth (Lake Huron) and sixth (Lake Michigan) largest lakes in the world, 15–35 tows were adequate to achieve target RSEs (15% and 30%) for ubiquitous species, but rarer species required much

  16. Abundances of demersal sharks and chimaera from 1994-2009 scientific surveys in the central Mediterranean Sea.

    PubMed

    Ragonese, Sergio; Vitale, Sergio; Dimech, Mark; Mazzola, Salvatore

    2013-01-01

    Bibliographic and data gathered in scientific bottom trawl surveys carried out off the Southern Coasts of Sicily (Mediterranean Sea), from 1994 to 2009 and between a depth of 10 and 800 m, were analysed in order to prepare a checklist of demersal sharks and chimaera, which are species sensitive to fisheries exploitation. Out of the 27 previously reported demersal shark and chimaera taxa in the Mediterranean, only 23 were found in literature and 20 sampled during the surveys in the investigated area. Among the species sampled in the surveys, only 2 ubiquitous (Squalusblainville and Scyliorhinuscanicula) and 3 deep-water (Chimaeramonstrosa , Centrophorusgranulosus and Galeusmelastomus) species showed a wide geographical distribution with a consistent abundance. Excluding the rare (such as Oxynotuscentrina) or uncommon shark (e.g. Squalusacanthias), the estimated frequencies of occurrence and abundance indexes show a possible risk of local extinction for the almost exclusively (e.g. angelshark, Squatina spp.) or preferential (e.g. Scyliorhinusstellaris) neritic species.

  17. Abundances of Demersal Sharks and Chimaera from 1994-2009 Scientific Surveys in the Central Mediterranean Sea

    PubMed Central

    Ragonese, Sergio; Vitale, Sergio; Dimech, Mark; Mazzola, Salvatore

    2013-01-01

    Bibliographic and data gathered in scientific bottom trawl surveys carried out off the Southern Coasts of Sicily (Mediterranean Sea), from 1994 to 2009 and between a depth of 10 and 800 m, were analysed in order to prepare a checklist of demersal sharks and chimaera, which are species sensitive to fisheries exploitation. Out of the 27 previously reported demersal shark and chimaera taxa in the Mediterranean, only 23 were found in literature and 20 sampled during the surveys in the investigated area. Among the species sampled in the surveys, only 2 ubiquitous (Squalusblainville and Scyliorhinuscanicula) and 3 deep-water (Chimaeramonstrosa, Centrophorusgranulosus and Galeusmelastomus) species showed a wide geographical distribution with a consistent abundance. Excluding the rare (such as Oxynotuscentrina) or uncommon shark (e.g. Squalusacanthias), the estimated frequencies of occurrence and abundance indexes show a possible risk of local extinction for the almost exclusively (e.g. angelshark, Squatina spp.) or preferential (e.g. Scyliorhinusstellaris) neritic species. PMID:24086386

  18. 30 CFR 250.1741 - If I drag a trawl across a site, what requirements must I meet?

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ...) You must drag the trawl in a grid-like pattern as shown in the following table: For a— You must drag..., or manifold 600-foot-radius circle centered on the structure location. (b) You must trawl 100...

  19. 30 CFR 250.1741 - If I drag a trawl across a site, what requirements must I meet?

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... § 250.1740, you must meet all of the requirements of this section. (a) You must drag the trawl in a grid... centered on the structure location. (b) You must trawl 100 percent of the limits described in paragraph...

  20. Fishes of Missouri River, chute, and flood plain habitats: Chapter 4 in Initial biotic survey of Lisbon Bottom, Big Muddy National Fish and Wildlife Refuge

    USGS Publications Warehouse

    Grady, Joanne; Milligan, Jim; Chapman, Duane C.; Ehrhardt, Ellen A.; Dieterman, Douglas J.; Galat, David L.; Hooker, John; Kubisiak, John; DeLonay, Aaron; Little, Edward E.; Robinson, Jack; Tibbs, John

    1999-01-01

    The Lisbon Bottom Unit of the Big Muddy National Fish and Wildlife Refuge (Refuge) is approximately 2,200 acres and is the first complete unit of the Refuge. Primary objectives of the Refuge are to create and restore diverse riverine aquatic habitats and reconnect the Missouri River to its flood plain where feasible. Management seeks to accomplish these objectives by encouraging natural processes of erosion, deposition, and succession to the greatest extent possible.One of the most salient aquatic features of the Lisbon Bottom Unit is a newly created 2-mile-long free-flowing chute, or side channel (Fig. 1). This chute began forming as a levee breech scour hole during the Great Flood of 1993. The chute continued to develop during the 1995 flood and finally cut through to a flowing side channel during the 1996 flood. Extensive erosion and bank sluffing continued during 1997 due to sustained high flows that occurred throughout most of the year. The chute has progressively become wider and deeper with a developing meander pattern and channel bars have begun to form. Lisbon Bottom also contains several seasonal and permanent wetlands and is subject to periodic flooding at high Missouri River stages.Eight studies have been completed or are ongoing to evaluate Missouri River fishes associated with various habitat components of Lisbon Bottom and adjacent Missouri River reaches (Table 1). Several are part of much larger investigations to evaluate fish use of flood-created habitat features, basinwide fish assessment, and endangered or candidate species concerns.At the Lisbon Bottom Unit or in the Missouri River adjacent to the unit 54 fish species were collected (Table 2). Eight of these species have either a protected status under State or Federal laws or biologists consider them to potentially qualify for protected status. The status of the following fish is listed in Table 2: pallid sturgeon x shovelnose sturgeon hybrid, paddlefish, northern pike, sturgeon chub, sicklefin

  1. 50 CFR Table 51 to Part 679 - Modified Gear Trawl Zone

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 50 Wildlife and Fisheries 13 2013-10-01 2013-10-01 false Modified Gear Trawl Zone 51 Table 51 to Part 679 Wildlife and Fisheries FISHERY CONSERVATION AND MANAGEMENT, NATIONAL OCEANIC AND ATMOSPHERIC..., Table 51 Table 51 to Part 679—Modified Gear Trawl Zone Longitude Latitude 171 45.00 W 61 00.00 N 169...

  2. 50 CFR Figure 26 to Part 679 - Modified Nonpelagic Trawl Gear

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 50 Wildlife and Fisheries 13 2013-10-01 2013-10-01 false Modified Nonpelagic Trawl Gear 26 Figure 26 to Part 679 Wildlife and Fisheries FISHERY CONSERVATION AND MANAGEMENT, NATIONAL OCEANIC AND... ALASKA Pt. 679, Fig. 26 Figure 26 to Part 679—Modified Nonpelagic Trawl Gear ER06OC10.050...

  3. 50 CFR Figure 26 to Part 679 - Modified Nonpelagic Trawl Gear

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 50 Wildlife and Fisheries 13 2012-10-01 2012-10-01 false Modified Nonpelagic Trawl Gear 26 Figure 26 to Part 679 Wildlife and Fisheries FISHERY CONSERVATION AND MANAGEMENT, NATIONAL OCEANIC AND... ALASKA Pt. 679, Fig. 26 Figure 26 to Part 679—Modified Nonpelagic Trawl Gear ER06OC10.050...

  4. 50 CFR Table 51 to Part 679 - Modified Gear Trawl Zone

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 50 Wildlife and Fisheries 13 2014-10-01 2014-10-01 false Modified Gear Trawl Zone 51 Table 51 to Part 679 Wildlife and Fisheries FISHERY CONSERVATION AND MANAGEMENT, NATIONAL OCEANIC AND ATMOSPHERIC..., Table 51 Table 51 to Part 679—Modified Gear Trawl Zone Longitude Latitude 171 45.00 W 61 00.00 N 169...

  5. 50 CFR Figure 26 to Part 679 - Modified Nonpelagic Trawl Gear

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 50 Wildlife and Fisheries 11 2011-10-01 2011-10-01 false Modified Nonpelagic Trawl Gear 26 Figure 26 to Part 679 Wildlife and Fisheries FISHERY CONSERVATION AND MANAGEMENT, NATIONAL OCEANIC AND... ALASKA Pt. 679, Fig. 26 Figure 26 to Part 679—Modified Nonpelagic Trawl Gear ER06OC10.050...

  6. 50 CFR Table 51 to Part 679 - Modified Gear Trawl Zone

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 50 Wildlife and Fisheries 11 2011-10-01 2011-10-01 false Modified Gear Trawl Zone 51 Table 51 to Part 679 Wildlife and Fisheries FISHERY CONSERVATION AND MANAGEMENT, NATIONAL OCEANIC AND ATMOSPHERIC..., Table 51 Table 51 to Part 679—Modified Gear Trawl Zone Longitude Latitude 171 45.00 W 61 00.00 N 169...

  7. 50 CFR Table 51 to Part 679 - Modified Gear Trawl Zone

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 50 Wildlife and Fisheries 13 2012-10-01 2012-10-01 false Modified Gear Trawl Zone 51 Table 51 to Part 679 Wildlife and Fisheries FISHERY CONSERVATION AND MANAGEMENT, NATIONAL OCEANIC AND ATMOSPHERIC..., Table 51 Table 51 to Part 679—Modified Gear Trawl Zone Longitude Latitude 171 45.00 W 61 00.00 N 169...

  8. 76 FR 54887 - Fisheries Off West Coast States; Pacific Coast Groundfish Fishery Management Plan; Trawl...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-09-02

    ..., with 3 exceptions (non-groundfish trawl gear for California halibut, ridgeback prawn, and sea cucumber... fisheries for ridgeback prawn, California halibut, and sea cucumber fisheries. No changes are needed for the... a vessel participating in the ridgeback prawn, sea cucumber, or California halibut trawl...

  9. 50 CFR 660.337 - Trawl rationalization program - data collection requirements.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... COAST STATES West Coast Groundfish Fisheries § 660.337 Trawl rationalization program - data collection... 50 Wildlife and Fisheries 9 2010-10-01 2010-10-01 false Trawl rationalization program - data collection requirements. 660.337 Section 660.337 Wildlife and Fisheries FISHERY CONSERVATION AND...

  10. 50 CFR Figure 12 to Part 679 - Bristol Bay Trawl Closure Area

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 50 Wildlife and Fisheries 11 2011-10-01 2011-10-01 false Bristol Bay Trawl Closure Area 12 Figure 12 to Part 679 Wildlife and Fisheries FISHERY CONSERVATION AND MANAGEMENT, NATIONAL OCEANIC AND... ALASKA Pt. 679, Fig. 12 Figure 12 to Part 679—Bristol Bay Trawl Closure Area ER30NO09.000 ...

  11. 50 CFR Figure 12 to Part 679 - Bristol Bay Trawl Closure Area

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 50 Wildlife and Fisheries 13 2013-10-01 2013-10-01 false Bristol Bay Trawl Closure Area 12 Figure 12 to Part 679 Wildlife and Fisheries FISHERY CONSERVATION AND MANAGEMENT, NATIONAL OCEANIC AND... ALASKA Pt. 679, Fig. 12 Figure 12 to Part 679—Bristol Bay Trawl Closure Area ER30NO09.000 ...

  12. 50 CFR Figure 12 to Part 679 - Bristol Bay Trawl Closure Area

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 50 Wildlife and Fisheries 13 2014-10-01 2014-10-01 false Bristol Bay Trawl Closure Area 12 Figure 12 to Part 679 Wildlife and Fisheries FISHERY CONSERVATION AND MANAGEMENT, NATIONAL OCEANIC AND... ALASKA Pt. 679, Fig. 12 Figure 12 to Part 679—Bristol Bay Trawl Closure Area ER30NO09.000 ...

  13. 50 CFR Figure 12 to Part 679 - Bristol Bay Trawl Closure Area

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 50 Wildlife and Fisheries 13 2012-10-01 2012-10-01 false Bristol Bay Trawl Closure Area 12 Figure 12 to Part 679 Wildlife and Fisheries FISHERY CONSERVATION AND MANAGEMENT, NATIONAL OCEANIC AND... ALASKA Pt. 679, Fig. 12 Figure 12 to Part 679—Bristol Bay Trawl Closure Area ER30NO09.000 ...

  14. 50 CFR Figure 12 to Part 679 - Bristol Bay Trawl Closure Area

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 50 Wildlife and Fisheries 9 2010-10-01 2010-10-01 false Bristol Bay Trawl Closure Area 12 Figure 12 to Part 679 Wildlife and Fisheries FISHERY CONSERVATION AND MANAGEMENT, NATIONAL OCEANIC AND... ALASKA Pt. 679, Fig. 12 Figure 12 to Part 679—Bristol Bay Trawl Closure Area ER30NO09.000 ...

  15. 50 CFR Figure 6 to Part 223 - TED Extension in Summer Flounder Trawl

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 50 Wildlife and Fisheries 7 2010-10-01 2010-10-01 false TED Extension in Summer Flounder Trawl 6 Figure 6 to Part 223 Wildlife and Fisheries NATIONAL MARINE FISHERIES SERVICE, NATIONAL OCEANIC AND.... 223, Fig. 6 Figure 6 to Part 223—TED Extension in Summer Flounder Trawl ER15OC99.001 ...

  16. The effects of trawling on the benthic fauna of the Gulf of Nicoya, Costa Rica.

    PubMed

    Rostad, T; Hansen, K L

    2001-12-01

    Four van Veen grab replicates where collected to sample macrofauna (organism retained on a 500 micron mesh sieve) at four stations in the Gulf of Nicoya, during October 24, 1997, January 16 and April 30, 1998. This information was used to search for any effects of trawling on the benthic fauna. Two stations where located in a trawled area, and two stations where in a protected area. Diversity (H') varied from 2.01 to 3.52 in the trawled area and from 2.13 to 2.78 in the protected area. Diversity was generally higher in the trawled area, and this was in contradiction to what we would have expected from other studies where the trend has been that trawling reduces diversity. Brittlestars and lancelets seemed to be the groups mostly harmed by the trawling, while amphipods where more abundant in trawled areas. The multivariate analyses did not reveal the patterns of faunal change as well as we hoped. This is surely because of our lack of more replicate samples. The multivariate analyses are easily confounded when few sites are analyzed. We have found differences in the type of fauna found in trawled and protected areas and, considering the differences in environmental variables in our stations and our lack of replication, this indicates that there are differences and a larger investigation is in order to reveal its magnitude.

  17. 77 FR 23159 - Fisheries of the Exclusive Economic Zone Off Alaska; Pacific Cod by Catcher Vessels Using Trawl...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-04-18

    ... Economic Zone Off Alaska; Pacific Cod by Catcher Vessels Using Trawl Gear in the Bering Sea and Aleutian... for Pacific cod by catcher vessels using trawl gear in the Bering Sea and Aleutian Islands management... directed fishing for Pacific cod by catcher vessels using trawl gear in the BSAI. After the effective...

  18. 76 FR 20891 - Fisheries of the Exclusive Economic Zone Off Alaska; Pacific Cod by Catcher Vessels Using Trawl...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-04-14

    ... Economic Zone Off Alaska; Pacific Cod by Catcher Vessels Using Trawl Gear in the Bering Sea and Aleutian... directed fishing for Pacific cod by catcher vessels using trawl gear in the Bering Sea and Aleutian Islands... allowable catch (TAC) of Pacific cod allocated to catcher vessels using trawl gear in the BSAI....

  19. 76 FR 57679 - Fisheries of the Exclusive Economic Zone Off Alaska; Shallow-Water Species by Vessels Using Trawl...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-09-16

    ... Economic Zone Off Alaska; Shallow- Water Species by Vessels Using Trawl Gear in the Gulf of Alaska AGENCY...-water species by vessels using trawl gear in the Gulf of Alaska (GOA) for 48 hours. This action is...-water species by vessels using trawl gear in the GOA under Sec. 679.21(d)(7)(i) on September 3, 2011...

  20. 75 FR 16359 - Fisheries of the Exclusive Economic Zone Off Alaska; Pacific Cod by Catcher Vessels Using Trawl...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-04-01

    ... Economic Zone Off Alaska; Pacific Cod by Catcher Vessels Using Trawl Gear in the Bering Sea and Aleutian... for Pacific cod by catcher vessels using trawl gear in the Bering Sea and Aleutian Islands management... cod allowable catch (TAC) specified for catcher vessels using trawl gear in the BSAI. DATES:...

  1. 76 FR 22057 - Fisheries of the Exclusive Economic Zone Off Alaska; Pacific Cod by Catcher Vessels Using Trawl...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-04-20

    ... Economic Zone Off Alaska; Pacific Cod by Catcher Vessels Using Trawl Gear in the Bering Sea and Aleutian... directed fishing for Pacific cod by catcher vessels using trawl gear in the Bering Sea and Aleutian Islands... allowable catch (TAC) of Pacific cod allocated to catcher vessels using trawl gear in the BSAI....

  2. 75 FR 12463 - Fisheries of the Exclusive Economic Zone Off Alaska; Pacific Cod by Catcher Vessels Using Trawl...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-03-16

    ... Economic Zone Off Alaska; Pacific Cod by Catcher Vessels Using Trawl Gear in the Bering Sea and Aleutian... for Pacific cod by catcher vessels using trawl gear in the Bering Sea and Aleutian Islands management... cod allowable catch (TAC) specified for catcher vessels using trawl gear in the BSAI. DATES:...

  3. 76 FR 18663 - Fisheries of the Exclusive Economic Zone Off Alaska; Pacific Cod by Catcher Vessels Using Trawl...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-04-05

    ... Economic Zone Off Alaska; Pacific Cod by Catcher Vessels Using Trawl Gear in the Bering Sea and Aleutian... for Pacific cod by catcher vessels using trawl gear in the Bering Sea and Aleutian Islands management... cod allowable catch (TAC) specified for catcher vessels using trawl gear in the BSAI. DATES:...

  4. 75 FR 56017 - Fisheries of the Exclusive Economic Zone Off Alaska; Shallow-Water Species by Vessels Using Trawl...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-09-15

    ... Economic Zone Off Alaska; Shallow- Water Species by Vessels Using Trawl Gear in the Gulf of Alaska AGENCY...-water species by vessels using trawl gear in the Gulf of Alaska (GOA). This action is necessary to fully... 679. NMFS prohibited directed fishing for shallow-water species by vessels using trawl gear in the...

  5. 77 FR 19564 - Fisheries of the Exclusive Economic Zone Off Alaska; Pacific Cod by Catcher Vessels Using Trawl...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-04-02

    ... Economic Zone Off Alaska; Pacific Cod by Catcher Vessels Using Trawl Gear in the Central Regulatory Area of... for Pacific cod by catcher vessels (CVs) using trawl gear in the Central Regulatory Area of the Gulf... Pacific cod total allowable catch apportioned to CVs using trawl gear in the Central Regulatory Area...

  6. 77 FR 11412 - Fisheries of the Exclusive Economic Zone Off Alaska; Pacific Cod by Catcher Vessels Using Trawl...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-02-27

    ... Economic Zone Off Alaska; Pacific Cod by Catcher Vessels Using Trawl Gear in the Western Regulatory Area of... for Pacific cod by catcher vessels (CVs) using trawl gear in the Western Regulatory Area of the Gulf... Pacific cod total allowable catch apportioned to CVs using trawl gear in the Western Regulatory Area...

  7. 78 FR 18528 - Fisheries of the Exclusive Economic Zone Off Alaska; Pacific Cod by Catcher Vessels Using Trawl...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-03-27

    ... Economic Zone Off Alaska; Pacific Cod by Catcher Vessels Using Trawl Gear in the Central Regulatory Area of... for Pacific cod by catcher vessels (CVs) using trawl gear in the Central Regulatory Area of the Gulf... Pacific cod total allowable catch apportioned to CVs using trawl gear in the Central Regulatory Area...

  8. 78 FR 15643 - Fisheries of the Exclusive Economic Zone Off Alaska; Pacific Cod by Catcher Vessels Using Trawl...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-03-12

    ... Economic Zone Off Alaska; Pacific Cod by Catcher Vessels Using Trawl Gear in the Bering Sea and Aleutian... for Pacific cod by catcher vessels using trawl gear in the Bering Sea and Aleutian Islands management... Pacific cod total allowable catch allocated to trawl catcher vessels in the BSAI. DATES: Effective...

  9. 77 FR 19147 - Fisheries of the Exclusive Economic Zone Off Alaska; Pacific Cod by Catcher Vessels Using Trawl...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-03-30

    ... Economic Zone Off Alaska; Pacific Cod by Catcher Vessels Using Trawl Gear in the Bering Sea and Aleutian... directed fishing for Pacific cod by catcher vessels using trawl gear in the Bering Sea and Aleutian Islands... cod total allowable catch (TAC) allocated to trawl catcher vessels in the BSAI. DATES: Effective...

  10. 78 FR 11790 - Fisheries of the Exclusive Economic Zone Off Alaska; Pacific Cod by Catcher Vessels Using Trawl...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-02-20

    ... Economic Zone Off Alaska; Pacific Cod by Catcher Vessels Using Trawl Gear in the Western Regulatory Area of... for Pacific cod by catcher vessels (CVs) using trawl gear in the Western Regulatory Area of the Gulf... Pacific cod total allowable catch apportioned to CVs using trawl gear in the Western Regulatory Area...

  11. Efficacy of a benthic trawl for sampling small-bodied fishes in large river systems

    USGS Publications Warehouse

    Herzog, D.P.; Barko, V.A.; Scheibe, J.S.; Hrabik, R.A.; Ostendorf, D.E.

    2005-01-01

    We conducted a study from 1998 to 2001 to determine the efficacy of a benthic trawl designed to increase species detection and reduce the incidence of zero catches of small-bodied fishes. We modified a standard two-seam slingshot balloon trawl by covering the entire trawl with a small-mesh cover. After completing 281 hauls with the modified (Missouri) trawl, we discovered that most fish passed through the body of the standard trawl and were captured in the cover. Logistic regression indicated no noticeable effect of the cover on the catch entering the standard portion of the modified trawl. However, some fishes (e.g., larval sturgeons Scaphirhynchus spp. and pallid sturgeon S. albus) were exclusively captured in the small-mesh cover, while the catch of small-bodied adult fish (e.g., chubs Macrhybopsis spp.) was significantly improved by use of the small-mesh cover design. The Missouri trawl significantly increased the number and species of small-bodied fishes captured over previously used designs and is a useful method for sampling the benthic fish community in moderate- to large-size river systems.

  12. Benchmarking Non-Hardware Balance-of-System (Soft) Costs for U.S. Photovoltaic Systems, Using a Bottom-Up Approach and Installer Survey - Second Edition

    SciTech Connect

    Friedman, B.; Ardani, K.; Feldman, D.; Citron, R.; Margolis, R.; Zuboy, J.

    2013-10-01

    This report presents results from the second U.S. Department of Energy (DOE) sponsored, bottom-up data-collection and analysis of non-hardware balance-of-system costs -- often referred to as 'business process' or 'soft' costs -- for U.S. residential and commercial photovoltaic (PV) systems. In service to DOE's SunShot Initiative, annual expenditure and labor-hour-productivity data are analyzed to benchmark 2012 soft costs related to (1) customer acquisition and system design (2) permitting, inspection, and interconnection (PII). We also include an in-depth analysis of costs related to financing, overhead, and profit. Soft costs are both a major challenge and a major opportunity for reducing PV system prices and stimulating SunShot-level PV deployment in the United States. The data and analysis in this series of benchmarking reports are a step toward the more detailed understanding of PV soft costs required to track and accelerate these price reductions.

  13. Bottom head assembly

    DOEpatents

    Fife, A.B.

    1998-09-01

    A bottom head dome assembly is described which includes, in one embodiment, a bottom head dome and a liner configured to be positioned proximate the bottom head dome. The bottom head dome has a plurality of openings extending there through. The liner also has a plurality of openings extending there through, and each liner opening aligns with a respective bottom head dome opening. A seal is formed, such as by welding, between the liner and the bottom head dome to resist entry of water between the liner and the bottom head dome at the edge of the liner. In the one embodiment, a plurality of stub tubes are secured to the liner. Each stub tube has a bore extending there through, and each stub tube bore is coaxially aligned with a respective liner opening. A seat portion is formed by each liner opening for receiving a portion of the respective stub tube. The assembly also includes a plurality of support shims positioned between the bottom head dome and the liner for supporting the liner. In one embodiment, each support shim includes a support stub having a bore there through, and each support stub bore aligns with a respective bottom head dome opening. 2 figs.

  14. Bottom head assembly

    DOEpatents

    Fife, Alex Blair

    1998-01-01

    A bottom head dome assembly which includes, in one embodiment, a bottom head dome and a liner configured to be positioned proximate the bottom head dome is described. The bottom head dome has a plurality of openings extending therethrough. The liner also has a plurality of openings extending therethrough, and each liner opening aligns with a respective bottom head dome opening. A seal is formed, such as by welding, between the liner and the bottom head dome to resist entry of water between the liner and the bottom head dome at the edge of the liner. In the one embodiment, a plurality of stub tubes are secured to the liner. Each stub tube has a bore extending therethrough, and each stub tube bore is coaxially aligned with a respective liner opening. A seat portion is formed by each liner opening for receiving a portion of the respective stub tube. The assembly also includes a plurality of support shims positioned between the bottom head dome and the liner for supporting the liner. In one embodiment, each support shim includes a support stub having a bore therethrough, and each support stub bore aligns with a respective bottom head dome opening.

  15. Evaluation of changes in macrobenthic standing stock and polychaete community structure along the south eastern Arabian Sea shelf during the monsoon trawl-ban

    NASA Astrophysics Data System (ADS)

    Abdul Jaleel, K. U.; Parameswaran, Usha V.; Gopal, Aiswarya; Khader, Chippy; Ganesh, T.; Sanjeevan, V. N.; Shunmugaraj, T.; Vijayan, Anil Kumar; Gupta, G. V. M.

    2015-07-01

    The south eastern Arabian Sea is characterized by moderate coastal upwelling, high biological production and subsurface oxygen depletion during the southwest monsoon (June-September). Concurrently, a seasonal closure to trawling activities (15th June-31st July) is implemented here, as a sustainable ecosystem management practise. The effects of monsoon driven environmental changes and consequences of trawling cessation on macrofauna were assessed, based on surveys at 12 sites (30-200 m) preceding and during different phases of the southwest monsoon. Macrofaunal density and biomass increased considerably towards the mid and late monsoon along the inner shelf (30-50 m) where trawling is intense, while no temporal changes were observed along the outer shelf (100-200 m). Density increased four-folds at the 30 m contour and three-folds at 50 m, while biomass nearly doubled at both depths, reflecting a marked increase in density of polychaetes (61-87% of macrofauna). The disproportionate increase in faunal density and biomass along the inner shelf (30-50 m) was due to abundance of juvenile polychaetes and dominance of small-sized opportunists towards late monsoon (August-September). A concurrent hike in nominal species count of polychaetes was also observed in the study area. The increase in polychaete standing stock and high density of planktonic larvae during onset and peak monsoon, coupled with occurrence of juveniles as well as gamete-bearing adults in sediments, indicates that the southwest monsoon is a peak breeding season for the dominant polychaetes in the region. The trawl-ban during this period facilitates the recoupment of benthos by maximising spawning success and larval settlement, thereby enhancing overall ecosystem integrity.

  16. Methods of analysis by the U.S. Geological Survey National Water Quality Laboratory; determination of organochlorine pesticides and polychlorinated biphenyls in bottom sediment by dual capillary-column gas chromatography with electron-capture detection

    USGS Publications Warehouse

    Foreman, William T.; Connor, Brooke F.; Furlong, Edward T.; Vaught, Deborah G.; Merten, Leslie M.

    1995-01-01

    A method for the determination of 30 individual organochlorine pesticides, total toxaphene, and total polychlorinated biphenyls (PCBs) in bottom sediment is described. The method isolates the pesticides and PCBs by solvent extraction with dichlorobenzene, removes inorganic sulfur, large naturally occurring molecules, and other unwanted interferences by gel permeation chromatography, and further cleans up and class fractionates the extract using adsorption chromatography. The com- pounds then are instrumentally determined using dual capillary-column gas chromatography with electron-capture detection. Reporting limits range from 1 to 5 micrograms per kilogram for 30 individual pesticides, 50 micrograms per kilogram for total PCBs, and 200 micrograms per kilogram for total toxaphene. The method also is designed to allow the simultaneous isolation of 79 other semivolatile organic compounds from the sediment, which are separately quantified using gas chromatography with mass spectrometric detection. The method was developed in support of the U.S. Geological Survey's National Water-Quality Assessment program.

  17. Survival of European plaice discarded from coastal otter trawl fisheries in the English Channel.

    PubMed

    Morfin, Marie; Kopp, Dorothée; Benoît, Hugues P; Méhault, Sonia; Randall, Peter; Foster, Robert; Catchpole, Thomas

    2017-09-12

    Species that have a high likelihood of surviving the discarding process have become great concern since the European Union reformed the Common Fisheries Policy and enacted a landing obligation prohibiting the discarding any individuals of species under quota. Among species presenting an elevated survival potential, plaice (Pleuronectes platessa) is one of the most discarded in the coastal otter trawl fishery in the English Channel. The objective of this study is to provide the most reliable estimates of plaice survival after release in commercial conditions, and to identify the factors that influence survival rates. A captivity experiment was conducted in January-February in the English fishery to assess the survival of discarded plaice as a function of a semi-quantitative index of fish vitality, which has been demonstrated to be a good proxy of fish survival in comparable fishing and environmental conditions. This study examined the potential of this index to estimate discard survival in three trials from the English and French fisheries and at three different seasons. The vitality index was then used to analyse the influence of several factors (fishing practices, environmental conditions and fish biological characteristics) on the discard survival. The survival rates for plaice were accurately estimated at 62.8% in January-February, 66.6% in November and 45.2% in July. While these rates remained substantial whatever the fishing, environmental or fish biological conditions, the time fish spent on the deck, the bottom and air temperatures, the tow depth and the fish length had a significant influence on plaice survival. In practice, plaice survival could be enhanced by releasing the fish early during catch sorting and avoiding exposure to extreme air temperatures. Copyright © 2017 Elsevier Ltd. All rights reserved.

  18. Methods of analysis by the U.S. Geological Survey National Water Quality Laboratory : determination of organophosphate pesticides in bottom sediment by gas chromatography with flame photometric detection

    USGS Publications Warehouse

    Jha, Virendra Kumar; Wydoski, Duane S.

    2003-01-01

    A method for the isolation of 20 parent organophosphate pesticides and 5 pesticide degradates from bottom-sediment samples is described. The compound O-ethyl-O-methyl-S-proplyphosphorothioate is reported as an estimated concentration because of variable performance. In this method, the sediment samples are centrifuged to remove excess waster mixed with anhydrous sodium sulfate and Soxhlet extracted overnight with dichloromethane (93 percent) and methanol (7 percent). The extract is concentrated and then filtered through a 0.2-micrometer polytetrafluoroethylene membrane syringe filter. An aliquot of the sample extract is quantitatively injected onto two polystyrene-divinylbenzene gel-permeation chromatographic columns connected in series. The compounds are eluted with dichloromethane and a fraction is collected for analysis, with some coextracted interferences, including elemental sulfur, separated and discarded. The aliquot is concentrated and solvent exchanged to ethyl acetate. The extract is analyzed by dual capillary-column gas chromatography with flame photometric detection. Single-operator method detection limits in sodium sulfate matrix samples ranged from 0.81 to 2 micrograms per kilogram. Method performance was validated by spiking all compounds into three different solid matrices (sodium sulfate, bed sediment from Clear Creek, and bed sediment from Evergreen Lake) at three different concentrations. Eight replicates were analyzed at each concentration in each matrix. Mean recoveries of method compounds spiked in Clear Creek samples ranged from 43 to 110 percent, and those in Evergreen Lake samples ranged from 62 to 118 percent for all pesticides. Mean recoveries of method compounds spiked in reagent sodium sulfate samples ranged from 41 to 101 percent for all pesticides. The only exception was O-ethyl-O-methyl-S-propylphosphorothioate, which had an average recovery of 35 percent, and, thus, sample concentration is reported as estimated ('E' remark code).

  19. 78 FR 7371 - Fisheries Off West Coast States; Pacific Coast Groundfish Fishery; Trawl Rationalization Program...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-02-01

    ...This action would implement a cost recovery program for the Pacific coast groundfish trawl rationalization program, which is a catch share program and type of limited access privilege program (LAPP), as required by the Magnuson-Stevens Fishery Conservation and Management Act (MSA). This action includes regulations that affect all trawl rationalization program sectors (Shorebased Individual Fishing Quota (IFQ) Program, Mothership Coop Program, and Catcher/Processor Coop Program) managed under the Pacific Coast Groundfish Fishery Management Plan (FMP).

  20. Energy direct inputs and greenhouse gas emissions of the main industrial trawl fishery of Brazil.

    PubMed

    Port, Dagoberto; Perez, Jose Angel Alvarez; de Menezes, João Thadeu

    2016-06-15

    This study provides first-time estimates of direct fuel inputs and greenhouse gas emissions produced by the trawl fishing fleet operating off southeastern and southern Brazil. Analyzed data comprised vessel characteristics, landings, fishing areas and trawling duration of 10,144 fishing operations monitored in Santa Catarina State from 2003 to 2011. Three main fishing strategies were differentiated: 'shrimp trawling', 'slope trawling' and 'pair trawling'. Jointly these operations burned over 141.5millionl of diesel to land 342.3millionkg of fish and shellfish. Annually, 0.36-0.48l were consumed for every kg of catch landed. Because all fishing strategies relied on multispecific catches to raise total incomes, estimates of fuel use intensity were generally low but increased 316-1025% if only nominal targets were considered. In nine years, trawling operations emitted 104.07GgC to the atmosphere, between 36,800-49,500tons CO2 per year. Copyright © 2016 Elsevier Ltd. All rights reserved.

  1. Impacts of crowding, trawl duration and air exposure on the physiology of stingarees (family: Urolophidae)

    PubMed Central

    Heard, Matthew; Van Rijn, Jason A.; Reina, Richard D.; Huveneers, Charlie

    2014-01-01

    Research on physiological stress and post-capture mortality of threatened species caught as bycatch is critical for the management of fisheries. The present study used laboratory simulations to examine the physiological stress response of sparsely spotted stingarees (Urolophus paucimaculatus) subjected to one of four different trawl treatments, including two different trawl durations as well as ancillary stressors of either air exposure or crowding. Physiological indicators (plasma lactate, urea, potassium and glucose) and changes in white blood cell counts were measured from blood samples taken throughout a 48 h recovery period. Mortality was low throughout this study (15% overall) and occurred only after >48 h following air exposure, crowding and 3 h trawl simulations. Plasma lactate, glucose and urea concentrations were identified as potential indicators of physiological stress, while plasma potassium and white blood cell counts were too variable to identify changes that would be expected to have biological consequences for stingarees. The characterization of the temporal profiles of physiological indicators facilitates a more accurate assessment of secondary stressors by identifying the best timing to sample stingaree blood when investigating post-capture stress physiology. High levels of lactate, increasing glucose and depressed urea were all recorded in response to air exposure following trawling, indicating that this is the primary source of stress in stingarees caught in trawling operations. These findings highlight the importance of improving bycatch sorting procedures to reduce the time out of the water for trawl-caught stingarees. PMID:27293661

  2. Invertebrate communities associated with hard bottom habitats in the South Atlantic Bight

    NASA Astrophysics Data System (ADS)

    Wenner, E. L.; Knott, D. M.; Van Dolah, R. F.; Burrell, V. G.

    1983-08-01

    Epibenthic invertebrates associated with nine hard bottom areas in the South Atlantic Bight between South Carolina and northern Florida were collected with dredge, trawl, suction and grab samplers to evaluate species composition, biomass, abundance, diversity, spatial distributions, and seasonality (winter and summer). Species composition changed noticeably with depth and season. Inner and outer shelf stations were least similar in species composition. Middle shelf areas were transitional and contained taxa characteristic of both inner and outer sites. Bryozoa (88 taxa), Cnidaria (85 taxa), Porifera (67 taxa), Annelida (261 taxa) and Mollusca (203 taxa) represented the richest taxonomic groups of the 1175 taxa collected. Both diversity (1175 total taxa) and biomass (1995 kg total) of invertebrates from hard bottom areas exceeded those reported in the literature for sand bottom communities. Sponges accounted for >60% of the total invertebrate biomass collected by dredge and trawl during both seasons. High diversity values were attributed primarily to habitat complexity and did not exhibit any discernible pattern with depth or latitude.

  3. Patterns of Dolphin Bycatch in a North-Western Australian Trawl Fishery

    PubMed Central

    Allen, Simon J.; Tyne, Julian A.; Kobryn, Halina T.; Bejder, Lars; Pollock, Kenneth H.; Loneragan, Neil R.

    2014-01-01

    The bycatch of small cetaceans in commercial fisheries is a global wildlife management problem. We used data from skippers' logbooks and independent observers to assess common bottlenose dolphin (Tursiops truncatus) bycatch patterns between 2003 and 2009 in the Pilbara Trawl Fishery, Western Australia. Both datasets indicated that dolphins were caught in all fishery areas, across all depths and throughout the year. Over the entire datasets, observer reported bycatch rates (n = 52 dolphins in 4,124 trawls, or 12.6 dolphins/1,000 trawls) were ca. double those reported by skippers (n = 180 dolphins in 27,904 trawls, or 6.5 dolphins/1,000 trawls). Generalised Linear Models based on observer data, which better explained the variation in dolphin bycatch, indicated that the most significant predictors of dolphin catch were: (1) vessel - one trawl vessel caught significantly more dolphins than three others assessed; (2) time of day – the lowest dolphin bycatch rates were between 00:00 and 05:59; and (3) whether nets included bycatch reduction devices (BRDs) - the rate was reduced by ca. 45%, from 18.8 to 10.3 dolphins/1,000 trawls, after their introduction. These results indicated that differences among vessels (or skippers' trawling techniques) and dolphin behavior (a diurnal pattern) influenced the rates of dolphin capture; and that spatial or seasonal adjustments to trawling effort would be unlikely to significantly reduce dolphin bycatch. Recent skipper's logbook data show that dolphin bycatch rates have not declined since those reported in 2006, when BRDs were introduced across the fishery. Modified BRDs, with top-opening escape hatches from which dolphins might escape to the surface, may be a more effective means of further reducing dolphin bycatch. The vulnerability of this dolphin population to trawling-related mortality cannot be assessed in the absence of an ongoing observer program and without information on trawler-associated dolphin community size

  4. Patterns of dolphin bycatch in a north-western Australian trawl fishery.

    PubMed

    Allen, Simon J; Tyne, Julian A; Kobryn, Halina T; Bejder, Lars; Pollock, Kenneth H; Loneragan, Neil R

    2014-01-01

    The bycatch of small cetaceans in commercial fisheries is a global wildlife management problem. We used data from skippers' logbooks and independent observers to assess common bottlenose dolphin (Tursiops truncatus) bycatch patterns between 2003 and 2009 in the Pilbara Trawl Fishery, Western Australia. Both datasets indicated that dolphins were caught in all fishery areas, across all depths and throughout the year. Over the entire datasets, observer reported bycatch rates (n = 52 dolphins in 4,124 trawls, or 12.6 dolphins/1,000 trawls) were ca. double those reported by skippers (n = 180 dolphins in 27,904 trawls, or 6.5 dolphins/1,000 trawls). Generalised Linear Models based on observer data, which better explained the variation in dolphin bycatch, indicated that the most significant predictors of dolphin catch were: (1) vessel--one trawl vessel caught significantly more dolphins than three others assessed; (2) time of day--the lowest dolphin bycatch rates were between 00:00 and 05:59; and (3) whether nets included bycatch reduction devices (BRDs)--the rate was reduced by ca. 45%, from 18.8 to 10.3 dolphins/1,000 trawls, after their introduction. These results indicated that differences among vessels (or skippers' trawling techniques) and dolphin behavior (a diurnal pattern) influenced the rates of dolphin capture; and that spatial or seasonal adjustments to trawling effort would be unlikely to significantly reduce dolphin bycatch. Recent skipper's logbook data show that dolphin bycatch rates have not declined since those reported in 2006, when BRDs were introduced across the fishery. Modified BRDs, with top-opening escape hatches from which dolphins might escape to the surface, may be a more effective means of further reducing dolphin bycatch. The vulnerability of this dolphin population to trawling-related mortality cannot be assessed in the absence of an ongoing observer program and without information on trawler-associated dolphin community size

  5. The substantial first impact of bottom fishing on rare biodiversity hotspots: a dilemma for evidence-based conservation.

    PubMed

    Cook, Robert; Fariñas-Franco, Jose M; Gell, Fiona R; Holt, Rohan H F; Holt, Terry; Lindenbaum, Charles; Porter, Joanne S; Seed, Ray; Skates, Lucie R; Stringell, Thomas B; Sanderson, William G

    2013-01-01

    This study describes the impact of the first passage of two types of bottom-towed fishing gear on rare protected shellfish-reefs formed by the horse mussel Modiolus modiolus (L.). One of the study sites was trawled and the other was scallop-dredged. Divers collected HD video imagery of epifauna from quadrats at the two study sites and directed infaunal samples from one site. The total number of epifaunal organisms was significantly reduced following a single pass of a trawl (90%) or scallop dredge (59%), as was the diversity of the associated community and the total number of M. modiolus at the trawled site. At both sites declines in anthozoans, hydrozoans, bivalves, echinoderms and ascidians accounted for most of the change. A year later, no recovery was evident at the trawled site and significantly fewer infaunal taxa (polychaetes, malacostracans, bivalves and ophuroids) were recorded in the trawl track. The severity of the two types of impact reflected the undisturbed status of the habitats compared to previous studies. As a 'priority habitat' the nature of the impacts described on M. modiolus communities are important to the development of conservation management policy and indicators of condition in Marine Protected Areas (EU Habitats Directive) as well as indicators of 'Good Environmental Status' under the European Union Marine Strategy Framework Directive. Conservation managers are under pressure to support decisions with good quality evidence. Elsewhere, indirect studies have shown declines of M. modiolus biogenic communities in fishing grounds. However, given the protected status of the rare habitat, premeditated demonstration of direct impact is unethical or illegal in Marine Protected Areas. This study therefore provides a unique opportunity to investigate the impact from fishing gear whilst at the same time reflecting on the dilemma of evidence-based conservation management.

  6. Vp structure in the largest slip area of the 2011 Tohoku-oki earthquake by airgun-ocean bottom seismometer surveys

    NASA Astrophysics Data System (ADS)

    Azuma, R.; Hino, R.; Ohta, Y.; Mochizuki, K.; Murai, Y.; Ito, Y.; Yakiwara, H.; Sato, T.; Shinohara, M.

    2015-12-01

    The huge coseismic slip during the 2011 Tohoku-oki earthquake concentrated beneath the lower inner slope of the middle Japan Trench (Miyagi region) and its amount sharply diminished along the trench within a hundred kilometers (e.g., Iinuma et al., 2012). The previous 2-D seismic study in the corresponding area found a notable Vp change in the hanging wall side of the megathrust (Azuma et al., in prep.). High-Vp body, corresponding to the rigid backstop block (Tsuru et al., 2002) was identified in the Miyagi, but was absent in the northern area. The spatial extent of the high-Vp anomaly almost coincides with the large slip zone and the correlation suggests that the heterogeneous structure in the overriding plate controlled the rupture process of the M-9 mainshock. To confirm the correlation between the seismic structure and coseismic slip distribution, we conducted a wide-angle survey in 2014 around the previous survey. In analysis, we operated a traveltime inversion for the first arrivals (Fujie et al., 2000) to obtain a rough model. Then, we made a trial-and-error adjustment of the structure model based on the travel time modeling with a 2D ray tracing (Zelt and Ellis, 1988). In the modeling, we tried to identify the location of the boundary between the backstop block and the low-Vp prism, because we assume the boundary (B/P boundary) to be correlated to the border of the high-slip zone during the 2011 event. The results showed sharp Vp transition from >3.7 km/s (backstop) to <3.4 km/s (prism) representing the B/P boundary. This feature agrees with the Vp variation or the along-trench distribution of the prism clarified by the previous studies. In the several observed record sections, there are clear shadow zone of the refracted arrivals from the backstop layer. The presence of the shadow indicates that a low Vp layer underlies the backstop, which is consistent with the previous reflection profiling made across the trench system. The low Vp prism is located

  7. Charmed Bottom Baryon Spectroscopy

    SciTech Connect

    Brown, Zachary S; Detmold, William; Meinel, Stefan; Orginos, Kostas

    2014-11-01

    The spectrum of doubly and triply heavy baryons remains experimentally unexplored to a large extent. Although the detection of such heavy particle states may lie beyond the reach of exper- iments for some time, it is interesting compute this spectrum from QCD and compare results between lattice calculations and continuum theoretical models. Several lattice calculations ex- ist for both doubly and triply charmed as well as doubly and triply bottom baryons. Here, we present preliminary results from the first lattice calculation of doubly and triply heavy baryons including both charm and bottom quarks. We use domain wall fermions for 2+1 flavors (up down and strange) of sea and valence quarks, a relativistic heavy quark action for the charm quarks, and non-relativistic QCD for the heavier bottom quarks. We present preliminary results for the ground state spectrum.

  8. Report on the invertebrate megafauna sampled by trawling in the Atlantic 3800 meter low-level radioactive waste disposal site. Final report

    SciTech Connect

    Carney, R.S.

    1983-08-01

    Four otter trawls were carried out in 1978 near the Atlantic deepsea low-level radioactive waste dumpsite located at a depth of 3800 meters, approximately 320 kilometers offshore, centered at 37 degrees 50'N, 70 degrees 35'W, and situated in the axis of the Hudson Canyon Channel. The megafauna collected in the vicinity of the dumpsite can be described as an ophiuroid-pagurid (brittle starfish-hermit crab) dominated, soft-bottom abyssal assemblage. The life histories of the predominant large invertebrates are presented and discussed. The report makes particular note of the need to differentiate between natural spatial variation of organisms and spatial variations resulting from man's activities, when designing dumpsite-related biological monitoring programs.

  9. The occupation of trawl fishing and the medical aid available to the Grimsby deep sea fisherman1

    PubMed Central

    Moore, S. R. W.

    1969-01-01

    Moore, S. R. W. (1969).Brit. J. industr. Med.,26, 1-24. The occupation of trawl fishing and the medical aid available to the Grimsby deep sea fisherman. The mortality of fishermen is twice that of coalminers. Because of the method of fishing the mortality of the trawlerman is probably higher. Outside the industry little is known about the occupation of trawl fishing. Its size, the number of men employed, and the number and distribution of trawlers are therefore described, with particular reference to the port of Grimsby. As near, middle, and deep water trawlers sail from Grimsby, its industry gives a good representation of conditions in the industry as a whole. The port and the fishing grounds are described. The composition of the trawler crew, their conditions of work, accommodation, and remuneration are explained. A description is given of the trawl apparatus, fishing operations, and the hazards involved, and extracts from the writer's diary of a fishing voyage are appended. The United Kingdom has ratified the Accommodation of Crews (Fishermen) Convention 1966 of the International Labour Organisation, and an informal survey of a modern trawler fleet showed that it fell short of the requirements of this Convention. Accommodation is confined and the crew live and work in close proximity and in conditions of physical discomfort. Trawlermen work for long hours under conditions which would not be tolerated by the shore worker. The method of payment is such that trawlermen may take unnecessary risks. Earnings depend on team work so that illness and injury are often not reported with consequent deterioration of the condition. Physical fatigue and lack of sleep contribute to an increased accident rate. It is therefore recommended that more men per trawler should be employed to allow shorter working hours. As the skipper and mate are paid wholly on a share basis, the remainder of the crew receiving, in addition, a basic wage, it `pays' the trawlermen to take risks. A

  10. Recovery of Seamount Precious Coral Beds From Heavy Trawling Disturbance with Links to Carbonate Chemistry Changes

    NASA Astrophysics Data System (ADS)

    Roark, E. B.; Baco-Taylor, A.; Morgan, N. B.; Shamberger, K.; Miller, K.; Brooks, J.

    2016-12-01

    Increasing anthropogenic impacts in the deep sea make studies of resilience and recovery time critical, with deep-sea hard-substrate habitats and large-scale disturbances having received little attention. Seamount hard-substrate habitats in particular are thought to have low resilience due to the slow growth rates and recruitment limitations of key structure-forming taxa. Seamounts of the far Northwestern Hawaiian Islands and Emperor Chain have had some of the heaviest trawl impacts in the world, from both fish and precious coral fisheries, and include sites that are still trawled and recovering ones that have been protected since establishment of the EEZ in 1977. To test the hypothesis of low resilience we compare these impacted seamounts to untrawled sites. We used the AUV Sentry in 2014 and 2015 to image nine features (three per "treatment") and analyze for substrate and visible megafauna. Sites in the "still trawled" treatment were characterized by extensive areas of bare substrate with abundant trawl scars. Sites in the "recovering" and "never trawled" locations had abundant megafauna in hard substrate areas. Initial comparisons of transects at 700m depth for three sites indicate that Yuryaku in the "still trawled" treatment had lower diversity and abundance of megafauna compared to the "recovering" and "never trawled" locations with a dominance of sea urchins. The "recovering" and "never trawled" sites were dominated by cnidarians, fishes, and echinoderms, but differed in dominant species, diversity, abundances and occurrence of dead coral skeletons. These preliminary results suggest that the recovering sites have not returned to a pre-impact community type in the 38 years since they were trawled. The megafauna distribution, in particular that of deep-sea corals, was compared to environmental water column variables at the study sites across the Northwestern Hawaiian Islands. Deep-sea corals with calcium carbonate skeletons were found living below the

  11. Laser bottom hole assembly

    DOEpatents

    Underwood, Lance D; Norton, Ryan J; McKay, Ryan P; Mesnard, David R; Fraze, Jason D; Zediker, Mark S; Faircloth, Brian O

    2014-01-14

    There is provided for laser bottom hole assembly for providing a high power laser beam having greater than 5 kW of power for a laser mechanical drilling process to advance a borehole. This assembly utilizes a reverse Moineau motor type power section and provides a self-regulating system that addresses fluid flows relating to motive force, cooling and removal of cuttings.

  12. 50 CFR Figure 7 to Part 679 - Location of Trawl Gear Test Areas in the GOA and the BSAI

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 50 Wildlife and Fisheries 9 2010-10-01 2010-10-01 false Location of Trawl Gear Test Areas in the GOA and the BSAI 7 Figure 7 to Part 679 Wildlife and Fisheries FISHERY CONSERVATION AND MANAGEMENT... EXCLUSIVE ECONOMIC ZONE OFF ALASKA Pt. 679, Fig. 7 Figure 7 to Part 679—Location of Trawl Gear Test Areas in...

  13. 50 CFR Figure 7 to Part 679 - Location of Trawl Gear Test Areas in the GOA and the BSAI

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 50 Wildlife and Fisheries 13 2012-10-01 2012-10-01 false Location of Trawl Gear Test Areas in the GOA and the BSAI 7 Figure 7 to Part 679 Wildlife and Fisheries FISHERY CONSERVATION AND MANAGEMENT... EXCLUSIVE ECONOMIC ZONE OFF ALASKA Pt. 679, Fig. 7 Figure 7 to Part 679—Location of Trawl Gear Test Areas in...

  14. 50 CFR Figure 7 to Part 679 - Location of Trawl Gear Test Areas in the GOA and the BSAI

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 50 Wildlife and Fisheries 13 2014-10-01 2014-10-01 false Location of Trawl Gear Test Areas in the GOA and the BSAI 7 Figure 7 to Part 679 Wildlife and Fisheries FISHERY CONSERVATION AND MANAGEMENT... EXCLUSIVE ECONOMIC ZONE OFF ALASKA Pt. 679, Fig. 7 Figure 7 to Part 679—Location of Trawl Gear Test Areas in...

  15. 50 CFR Figure 7 to Part 679 - Location of Trawl Gear Test Areas in the GOA and the BSAI

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 50 Wildlife and Fisheries 13 2013-10-01 2013-10-01 false Location of Trawl Gear Test Areas in the GOA and the BSAI 7 Figure 7 to Part 679 Wildlife and Fisheries FISHERY CONSERVATION AND MANAGEMENT... EXCLUSIVE ECONOMIC ZONE OFF ALASKA Pt. 679, Fig. 7 Figure 7 to Part 679—Location of Trawl Gear Test Areas in...

  16. 50 CFR Figure 7 to Part 679 - Location of Trawl Gear Test Areas in the GOA and the BSAI

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 50 Wildlife and Fisheries 11 2011-10-01 2011-10-01 false Location of Trawl Gear Test Areas in the GOA and the BSAI 7 Figure 7 to Part 679 Wildlife and Fisheries FISHERY CONSERVATION AND MANAGEMENT... EXCLUSIVE ECONOMIC ZONE OFF ALASKA Pt. 679, Fig. 7 Figure 7 to Part 679—Location of Trawl Gear Test Areas in...

  17. A case study on pseudo 3-D Chirp sub-bottom profiler (SBP) survey for the detection of a fault trace in shallow sedimentary layers at gas hydrate site in the Ulleung Basin, East Sea

    NASA Astrophysics Data System (ADS)

    Kim, Young-Jun; Koo, Nam-Hyung; Cheong, Snons; Kim, Jung-Ki; Chun, Jong-Hwa; Shin, Sung-Ryul; Riedel, Michael; Lee, Ho-Young

    2016-10-01

    A pseudo 3-D Chirp sub-bottom profiler (SBP) survey was conducted to define the extension of a fault that was previously identified on low-resolution 2-D seismic data with an emphasis on the shallow sedimentary layers and to determine if the fault extends to the seafloor. The geophysical survey was conducted as part of an environmental impact assessment for a proposed gas hydrate production test in the Ulleung Basin, East Sea. The Chirp SBP raw data were acquired over an area of 1 km × 1 km with an average line spacing of 20 m. To produce a 3-D Chirp SBP volume, we developed an optimal processing sequence that was divided into two steps. The first phase of 2-D data processing included a sweep signature estimation, correlation, deconvolution, swell effect correction, and migration. The second phase of 3-D data processing was composed of a bin design, bin gathering of the final processed 2-D data set, amplitude normalization, and residual statics correction. The 3-D Chirp SBP volume provides enhanced imaging especially due to the residual static processing using a moving average method and shows better continuity of the sedimentary layers and consistency of the reflection events than the individual 2-D lines. Deformation of the seafloor as a result of the fault was detected, and the fault offset increases in the deeper sedimentary layers. We also determined that the fault strikes northwest-southeast. However, the shallow sub-seafloor sediments have high porosities and therefore do not exhibit brittle fault-behavior but rather deform continuously due to fault movement.

  18. Trawling bats exploit an echo-acoustic ground effect

    PubMed Central

    Zsebok, Sandor; Kroll, Ferdinand; Heinrich, Melina; Genzel, Daria; Siemers, Björn M.; Wiegrebe, Lutz

    2013-01-01

    A water surface acts not only as an optic mirror but also as an acoustic mirror. Echolocation calls emitted by bats at low heights above water are reflected away from the bat, and hence the background clutter is reduced. Moreover, targets on the surface create an enhanced echo. Here, we formally quantified the effect of the surface and target height on both target detection and -discrimination in a combined laboratory and field approach with Myotis daubentonii. In a two-alternative, forced-choice paradigm, the bats had to detect a mealworm and discriminate it from an inedible dummy (20 mm PVC disc). Psychophysical performance was measured as a function of height above either smooth surfaces (water or PVC) or above a clutter surface (artificial grass). At low heights above the clutter surface (10, 20, or 35 cm), the bats' detection performance was worse than above a smooth surface. At a height of 50 cm, the surface structure had no influence on target detection. Above the clutter surface, also target discrimination was significantly impaired with decreasing target height. A detailed analysis of the bats' echolocation calls during target approach shows that above the clutter surface, the bats produce calls with significantly higher peak frequency. Flight-path reconstruction revealed that the bats attacked an target from below over water but from above over a clutter surface. These results are consistent with the hypothesis that trawling bats exploit an echo-acoustic ground effect, in terms of a spatio-temporal integration of direct reflections with indirect reflections from the water surface, to optimize prey detection and -discrimination not only for prey on the water but also for some range above. PMID:23576990

  19. Bio-economic evaluation of implementing trawl fishing gear with different selectivity.

    PubMed

    Kronbak, Lone Grønbaek; Nielsen, J Rasmus; Jørgensen, Ole A; Vestergaard, Niels

    2009-08-01

    The paper develops a biological-economic evaluation tool to analyse the consequences for trawl fishers of implementing more selective fishing technologies. This is done by merging a dynamic biological population model and an economic cost-benefit evaluation framework to describe the consequences for the fish stocks, fishermen and society. The bio-economic evaluation is applied to the case of the Danish trawl fishery in Kattegat and Skagerrak, which experiences a high level of discards and bycatches of several species. Four different kinds of selectivity scenarios are evaluated in comparison with a baseline. The results from the evaluation are indicators for the consequences on ecological and economic levels. The results show that implementation of different selective fishing gear in the Kattegat and Skagerrak mixed trawl fisheries generally implies a trade off over time between rebuilding the stocks and economic loss. Moreover, the analysis shows that implementation of more selective gear is not always beneficial.

  20. Influence of the hydrodynamic conditions on the accessibility of Aristeus antennatus and other demersal species to the deep water trawl fishery off the Balearic Islands (western Mediterranean)

    NASA Astrophysics Data System (ADS)

    Amores, Angel; Rueda, Lucía; Monserrat, Sebastià; Guijarro, Beatriz; Pasqual, Catalina; Massutí, Enric

    2014-10-01

    Monthly catches per unit of effort (CPUE) of adult red shrimp (Aristeus antennatus), reported in the deep water bottom trawl fishery developed on the Sóller fishing ground off northern Mallorca (Western Mediterranean), and the mean ocean surface vorticity in the surrounding areas are compared between 2000 and 2010. A good correlation is found between the rises in the surrounding surface vorticity and the drops in the CPUE of the adult red shrimp. This correlation could be explained by assuming that most of the surface vorticity episodes could reach the bottom, increasing the seabed velocities and producing sediment resuspension, which could affect the near bottom water turbidity. A. antennatus would respond to this increased turbidity disappearing from the fishing grounds, probably moving downwards to the deeper waters. This massive displacement of red shrimp specimens away from the fishing grounds would consequently decrease their accessibility to fishing exploitation. Similar although more intense responses have been observed during the downslope shelf dense water current episodes that occurred in a submarine canyon, northeast of the Iberian peninsula. The proposed mechanism suggesting how the surface vorticity observed can affect the bottom sediments is investigated using a year-long moored near-bottom current meter and a sediment trap moored near the fishing grounds. The relationship between vorticity and catches is also explored for fish species (Galeus melastomus, Micromesistius poutassou, Phycis blennoides) and other crustacean (Geryon longipes and Nephrops norvegicus), considered as by-catch of the deep water fishery in the area. Results appear to support the suggestion that the water turbidity generated by the vorticity episodes is significant enough to affect the dynamics of the demersal species.

  1. 48. Bottom of shock absorber, bottom of launch tube, soda ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    48. Bottom of shock absorber, bottom of launch tube, soda bottle liter at right - Ellsworth Air Force Base, Delta Flight, Launch Facility, On County Road T512, south of Exit 116 off I-90, Interior, Jackson County, SD

  2. Charmed Bottom Baryon Spectroscopy

    SciTech Connect

    Zachary Brown, William Detmold, Stefan Meinel, Konstantinos Orginos

    2012-09-01

    The arena of doubly and triply heavy baryons remains experimentally unexplored to a large extent. This has led to a great deal of theoretical effort being put forth in the calculation of mass spectra in this sector. Although the detection of such heavy particle states may lie beyond the reach of experiments for some time, it is interesting to compare results between lattice QCD computations and continuum theoretical models. Several recent lattice QCD calculations exist for both doubly and triply charmed as well as doubly and triply bottom baryons. In this work we present preliminary results from the first lattice calculation of the mass spectrum of doubly and triply heavy baryons including both charm and bottom quarks. The wide range of quark masses in these systems require that the various flavors of quarks be treated with different lattice actions. We use domain wall fermions for 2+1 flavors (up down and strange) of sea and valence quarks, a relativistic heavy quark action for the charm quarks, and non-relativistic QCD for the heavier bottom quarks. The calculation of the ground state spectrum is presented and compared to recent models.

  3. Dissolver vessel bottom assembly

    DOEpatents

    Kilian, Douglas C.

    1976-01-01

    An improved bottom assembly is provided for a nuclear reactor fuel reprocessing dissolver vessel wherein fuel elements are dissolved as the initial step in recovering fissile material from spent fuel rods. A shock-absorbing crash plate with a convex upper surface is disposed at the bottom of the dissolver vessel so as to provide an annular space between the crash plate and the dissolver vessel wall. A sparging ring is disposed within the annular space to enable a fluid discharged from the sparging ring to agitate the solids which deposit on the bottom of the dissolver vessel and accumulate in the annular space. An inlet tangential to the annular space permits a fluid pumped into the annular space through the inlet to flush these solids from the dissolver vessel through tangential outlets oppositely facing the inlet. The sparging ring is protected against damage from the impact of fuel elements being charged to the dissolver vessel by making the crash plate of such a diameter that the width of the annular space between the crash plate and the vessel wall is less than the diameter of the fuel elements.

  4. 50 CFR 660.114 - Trawl fishery-economic data collection program.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ...), NMFS, Northwest Fisheries Science Center, 2725 Montlake Boulevard East, Seattle, WA 98112. A complete... 50 Wildlife and Fisheries 13 2013-10-01 2013-10-01 false Trawl fishery-economic data collection... OCEANIC AND ATMOSPHERIC ADMINISTRATION, DEPARTMENT OF COMMERCE (CONTINUED) FISHERIES OFF WEST COAST STATES...

  5. 50 CFR 660.114 - Trawl fishery-economic data collection program.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ...), NMFS, Northwest Fisheries Science Center, 2725 Montlake Boulevard East, Seattle, WA 98112. A complete... 50 Wildlife and Fisheries 13 2012-10-01 2012-10-01 false Trawl fishery-economic data collection... OCEANIC AND ATMOSPHERIC ADMINISTRATION, DEPARTMENT OF COMMERCE (CONTINUED) FISHERIES OFF WEST COAST STATES...

  6. A ‘Simple Anterior Fish Excluder’ (SAFE) for Mitigating Penaeid-Trawl Bycatch

    PubMed Central

    McHugh, Matthew J.; Broadhurst, Matt K.; Sterling, David J.; Millar, Russell B.

    2015-01-01

    Various plastic strips and sheets (termed ‘simple anterior fish excluders’−SAFEs) were positioned across the openings of penaeid trawls in attempts at reducing the unwanted bycatches of small teleosts. Initially, three SAFEs (a single wire without, and with small and large plastic panels) were compared against a control (no SAFE) on paired beam trawls. All SAFEs maintained targeted Metapenaeus macleayi catches, while the largest plastic SAFE significantly reduced total bycatch by 51% and the numbers of Pomatomus saltatrix, Mugil cephalus and Herklotsichthys castelnaui by up to 58%. A redesigned SAFE (‘continuous plastic’) was subsequently tested (against a control) on paired otter trawls, significantly reducing total bycatch by 28% and P. saltatrix and H. castelnaui by up to 42%. The continuous-plastic SAFE also significantly reduced M. macleayi catches by ~7%, but this was explained by ~5% less wing-end spread, and could be simply negated through otter-board refinement. Further work is required to refine the tested SAFEs, and to quantify species-specific escape mechanisms. Nevertheless, the SAFE concept might represent an effective approach for improving penaeid-trawl selectivity. PMID:25837892

  7. 50 CFR 660.333 - Open access non-groundfish trawl fishery-management measures.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... engaged in fishing for pink shrimp, ridgeback prawns, California halibut, or sea cucumbers. Trip limits for groundfish retained in the ridgeback prawn, California halibut, or sea cucumber fisheries are in... the tail.” (d) Participation in the sea cucumber fishery. A trawl vessel will be considered to...

  8. 50 CFR 660.333 - Open access non-groundfish trawl fishery-management measures.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... engaged in fishing for pink shrimp, ridgeback prawns, California halibut, or sea cucumbers. Trip limits for groundfish retained in the ridgeback prawn, California halibut, or sea cucumber fisheries are in... swinging or fanning of the tail.” (2) (d) Participation in the sea cucumber fishery. A trawl vessel will...

  9. 50 CFR 660.333 - Open access non-groundfish trawl fishery-management measures.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... engaged in fishing for pink shrimp, ridgeback prawns, California halibut, or sea cucumbers. Trip limits for groundfish retained in the ridgeback prawn, California halibut, or sea cucumber fisheries are in... the tail.” (d) Participation in the sea cucumber fishery. A trawl vessel will be considered to...

  10. 50 CFR 660.333 - Open access non-groundfish trawl fishery-management measures.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... engaged in fishing for pink shrimp, ridgeback prawns, California halibut, or sea cucumbers. Trip limits for groundfish retained in the ridgeback prawn, California halibut, or sea cucumber fisheries are in... swinging or fanning of the tail.” (2) (d) Participation in the sea cucumber fishery. A trawl vessel will...

  11. 50 CFR 660.333 - Open access non-groundfish trawl fishery-management measures.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... engaged in fishing for pink shrimp, ridgeback prawns, California halibut, or sea cucumbers. Trip limits for groundfish retained in the ridgeback prawn, California halibut, or sea cucumber fisheries are in... the tail.” (d) Participation in the sea cucumber fishery. A trawl vessel will be considered to...

  12. 77 FR 38266 - Sea Turtle Conservation; Shrimp Trawling Requirements; Public Hearing

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-06-27

    ... From the Federal Register Online via the Government Publishing Office DEPARTMENT OF COMMERCE National Oceanic and Atmospheric Administration 50 CFR Part 223 RIN 0648-BC10 Sea Turtle Conservation; Shrimp Trawling Requirements; Public Hearing AGENCY: National Marine Fisheries Service (NMFS), National...

  13. 77 FR 48106 - Sea Turtle Conservation; Shrimp and Summer Flounder Trawling Requirements; Correction

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-08-13

    ... From the Federal Register Online via the Government Publishing Office ] DEPARTMENT OF COMMERCE National Oceanic and Atmospheric Administration 50 CFR Part 223 RIN 0648-AW93 Sea Turtle Conservation; Shrimp and Summer Flounder Trawling Requirements; Correction AGENCY: National Marine Fisheries Service...

  14. 77 FR 37647 - Sea Turtle Conservation; Shrimp Trawling Requirements; Public Hearing Notification

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-06-22

    ... From the Federal Register Online via the Government Publishing Office DEPARTMENT OF COMMERCE National Oceanic and Atmospheric Administration 50 CFR Part 223 RIN 0648-BC10 Sea Turtle Conservation; Shrimp Trawling Requirements; Public Hearing Notification AGENCY: National Marine Fisheries Service (NMFS...

  15. A 'simple anterior fish excluder' (SAFE) for mitigating penaeid-trawl bycatch.

    PubMed

    McHugh, Matthew J; Broadhurst, Matt K; Sterling, David J; Millar, Russell B

    2015-01-01

    Various plastic strips and sheets (termed 'simple anterior fish excluders'-SAFEs) were positioned across the openings of penaeid trawls in attempts at reducing the unwanted bycatches of small teleosts. Initially, three SAFEs (a single wire without, and with small and large plastic panels) were compared against a control (no SAFE) on paired beam trawls. All SAFEs maintained targeted Metapenaeus macleayi catches, while the largest plastic SAFE significantly reduced total bycatch by 51% and the numbers of Pomatomus saltatrix, Mugil cephalus and Herklotsichthys castelnaui by up to 58%. A redesigned SAFE ('continuous plastic') was subsequently tested (against a control) on paired otter trawls, significantly reducing total bycatch by 28% and P. saltatrix and H. castelnaui by up to 42%. The continuous-plastic SAFE also significantly reduced M. macleayi catches by ~7%, but this was explained by ~5% less wing-end spread, and could be simply negated through otter-board refinement. Further work is required to refine the tested SAFEs, and to quantify species-specific escape mechanisms. Nevertheless, the SAFE concept might represent an effective approach for improving penaeid-trawl selectivity.

  16. 50 CFR Figure 6 to Part 223 - TED Extension in Summer Flounder Trawl

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 50 Wildlife and Fisheries 10 2012-10-01 2012-10-01 false TED Extension in Summer Flounder Trawl 6 Figure 6 to Part 223 Wildlife and Fisheries NATIONAL MARINE FISHERIES SERVICE, NATIONAL OCEANIC AND ATMOSPHERIC ADMINISTRATION, DEPARTMENT OF COMMERCE MARINE MAMMALS THREATENED MARINE AND ANADROMOUS SPECIES...

  17. 50 CFR Figure 6 to Part 223 - TED Extension in Summer Flounder Trawl

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 50 Wildlife and Fisheries 9 2011-10-01 2011-10-01 false TED Extension in Summer Flounder Trawl 6 Figure 6 to Part 223 Wildlife and Fisheries NATIONAL MARINE FISHERIES SERVICE, NATIONAL OCEANIC AND ATMOSPHERIC ADMINISTRATION, DEPARTMENT OF COMMERCE MARINE MAMMALS THREATENED MARINE AND ANADROMOUS SPECIES...

  18. 50 CFR Figure 1 to Part 660... - Diagram of Selective Flatfish Trawl

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 50 Wildlife and Fisheries 13 2014-10-01 2014-10-01 false Diagram of Selective Flatfish Trawl 1 Figure 1 to Part 660, Subpart D Wildlife and Fisheries FISHERY CONSERVATION AND MANAGEMENT, NATIONAL OCEANIC AND ATMOSPHERIC ADMINISTRATION, DEPARTMENT OF COMMERCE (CONTINUED) FISHERIES OFF WEST COAST...

  19. 50 CFR Figure 1 to Part 660... - Diagram of Selective Flatfish Trawl

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 50 Wildlife and Fisheries 11 2011-10-01 2011-10-01 false Diagram of Selective Flatfish Trawl 1 Figure 1 to Part 660, Subpart D Wildlife and Fisheries FISHERY CONSERVATION AND MANAGEMENT, NATIONAL... Pt. 660, Subpt. D, Fig. 1 Figure 1 to Part 660, Subpart D—Diagram of Selective Flatfish...

  20. 50 CFR Figure 1 to Part 660... - Diagram of Selective Flatfish Trawl

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 50 Wildlife and Fisheries 13 2013-10-01 2013-10-01 false Diagram of Selective Flatfish Trawl 1 Figure 1 to Part 660, Subpart D Wildlife and Fisheries FISHERY CONSERVATION AND MANAGEMENT, NATIONAL... Pt. 660, Subpt. D, Fig. 1 Figure 1 to Part 660, Subpart D—Diagram of Selective Flatfish...

  1. 50 CFR Figure 1 to Part 660... - Diagram of Selective Flatfish Trawl

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 50 Wildlife and Fisheries 13 2012-10-01 2012-10-01 false Diagram of Selective Flatfish Trawl 1 Figure 1 to Part 660, Subpart D Wildlife and Fisheries FISHERY CONSERVATION AND MANAGEMENT, NATIONAL... Pt. 660, Subpt. D, Fig. 1 Figure 1 to Part 660, Subpart D—Diagram of Selective Flatfish...

  2. 50 CFR Figure 1 to Part 660... - Diagram of Selective Flatfish Trawl

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 50 Wildlife and Fisheries 9 2010-10-01 2010-10-01 false Diagram of Selective Flatfish Trawl 1 Figure 1 to Part 660, Subpart D Wildlife and Fisheries FISHERY CONSERVATION AND MANAGEMENT, NATIONAL... Pt. 660, Subpt. D, Fig. 1 Figure 1 to Part 660, Subpart D—Diagram of Selective Flatfish...

  3. Sensitivity of macrobenthic secondary production to trawling in the English sector of the Greater North Sea: A biological trait approach

    NASA Astrophysics Data System (ADS)

    Bolam, S. G.; Coggan, R. C.; Eggleton, J.; Diesing, M.; Stephens, D.

    2014-01-01

    Demersal trawling constitutes the most significant human impact on both the structure and functioning of coastal seabed fauna. While a number of studies have assessed the impacts of trawling on faunal community structure and the degree to which different taxa are vulnerable to trawling, few have focused on how these impacts affect important ecological functions of the seabed. In this study, we use biological trait analysis (BTA) to assess the relative sensitivity of benthic macrofauna to trawling, in both the short- and long-term, and use this information to describe the spatial variation in sensitivity of secondary production for the Greater North Sea (GNS). Within the GNS, estimates of total production varied by almost three orders of magnitude, from 1.66 kJ m- 2 y- 1 to 968.9 kJ m- 2 y- 1. Large-scale patterns were observed in the proportion of secondary production derived from trawling-sensitive taxa. In the southern North Sea, total production is predominantly governed by taxa with low sensitivity to trawling, whereas production is relatively trawling-sensitive in the northern North Sea and western English Channel. In general, the more sensitive and productive regions are associated with poorly-sorted, gravelly or muddy sediments, while the less sensitive and less productive regions are associated with well-sorted, sandy substrates. These relationships between production sensitivity and environmental features are primarily due to variations in long-term recovery; total production of most assemblages is highly sensitive to the direct impacts of trawling. We discuss the implications of these findings for management 1decisions to improve the environmental sustainability of trawling.

  4. How Many Fish Need to Be Measured to Effectively Evaluate Trawl Selectivity?

    PubMed Central

    Santos, Juan; Sala, Antonello

    2016-01-01

    The aim of this study was to provide practitioners working with trawl selectivity with general and easily understandable guidelines regarding the fish sampling effort necessary during sea trials. In particular, we focused on how many fish would need to be caught and length measured in a trawl haul in order to assess the selectivity parameters of the trawl at a designated uncertainty level. We also investigated the dependency of this uncertainty level on the experimental method used to collect data and on the potential effects of factors such as the size structure in the catch relative to the size selection of the gear. We based this study on simulated data created from two different fisheries: the Barents Sea cod (Gadus morhua) trawl fishery and the Mediterranean Sea multispecies trawl fishery represented by red mullet (Mullus barbatus). We used these two completely different fisheries to obtain results that can be used as general guidelines for other fisheries. We found that the uncertainty in the selection parameters decreased with increasing number of fish measured and that this relationship could be described by a power model. The sampling effort needed to achieve a specific uncertainty level for the selection parameters was always lower for the covered codend method compared to the paired-gear method. In many cases, the number of fish that would need to be measured to maintain a specific uncertainty level was around 10 times higher for the paired-gear method than for the covered codend method. The trends observed for the effect of sampling effort in the two fishery cases investigated were similar; therefore the guidelines presented herein should be applicable to other fisheries. PMID:27560696

  5. How Many Fish Need to Be Measured to Effectively Evaluate Trawl Selectivity?

    PubMed

    Herrmann, Bent; Sistiaga, Manu; Santos, Juan; Sala, Antonello

    2016-01-01

    The aim of this study was to provide practitioners working with trawl selectivity with general and easily understandable guidelines regarding the fish sampling effort necessary during sea trials. In particular, we focused on how many fish would need to be caught and length measured in a trawl haul in order to assess the selectivity parameters of the trawl at a designated uncertainty level. We also investigated the dependency of this uncertainty level on the experimental method used to collect data and on the potential effects of factors such as the size structure in the catch relative to the size selection of the gear. We based this study on simulated data created from two different fisheries: the Barents Sea cod (Gadus morhua) trawl fishery and the Mediterranean Sea multispecies trawl fishery represented by red mullet (Mullus barbatus). We used these two completely different fisheries to obtain results that can be used as general guidelines for other fisheries. We found that the uncertainty in the selection parameters decreased with increasing number of fish measured and that this relationship could be described by a power model. The sampling effort needed to achieve a specific uncertainty level for the selection parameters was always lower for the covered codend method compared to the paired-gear method. In many cases, the number of fish that would need to be measured to maintain a specific uncertainty level was around 10 times higher for the paired-gear method than for the covered codend method. The trends observed for the effect of sampling effort in the two fishery cases investigated were similar; therefore the guidelines presented herein should be applicable to other fisheries.

  6. Impacts of trawling on benthic macro-fauna and -flora of the Spencer Gulf prawn fishing grounds

    NASA Astrophysics Data System (ADS)

    Svane, Ib; Hammett, Zoe; Lauer, Peter

    2009-05-01

    The overall effects of trawling on benthic habitats and their assemblages are dependent on the distribution and intensity of trawl effort. The benthic habitats of the Spencer Gulf prawn trawling grounds are subjected to known variable levels of trawling disturbance recorded from fisher's logbooks. These habitats have not been quantitatively investigated. The aim of the study was firstly to characterise the macro-faunal and -floral assemblages and secondly, to comparatively assess trawl impact by testing the null hypothesis of no differences between five sites exposed to different intensity of trawl effort. The distribution and abundance of benthic macro-fauna and -flora were studied at two sampling resolutions by using beam trawl sampling (˜10,000 m 2) and underwater stereophotography (˜4.5 m 2) at five sites with different levels of trawl disturbance (effort). The results showed that the Spencer Gulf prawn trawling grounds are characterised by sandy sediments with a low content of silt and clay, with the exception of one site with very fine gravel. Biomass, abundance and cover of macro-fauna and -flora were generally low throughout, but with large differences among sites. Biomass, abundance and cover were found to be negatively correlated to both trawl hours from 1994-1998 and during the period of study. ANOSIM and SIMPER analyses using biomass, abundance and percentage cover as variables showed significant differences between sites with eight species or taxonomic groups contributing more than 10% to the observed similarity within sites. The two northern sites were dominated by sponges and the bearded mussel, Trichomya hirsutus, and the southern hammer oyster, Malleus meridianus. Other species that contributed to the similarity within sites were the ascidian, Polycarpa viridis, mobile epifauna (the blue swimmer crab, Portunus pelagicus, and the western king prawn, Penaeus (Melicertus) latisulcatus) and demersal fish species (Degens leatherjacket, Thamnaconus

  7. Biodiversity of suprabenthic peracarid assemblages from the Blanes Canyon region (NW Mediterranean Sea) in relation to natural disturbance and trawling pressure

    NASA Astrophysics Data System (ADS)

    Almeida, Mariana; Frutos, Inmaculada; Company, Joan B.; Martin, Daniel; Romano, Chiara; Cunha, Marina R.

    2017-03-01

    Blanes Canyon and its adjacent margin are important fishery areas (mainly by bottom trawling) located in a highly energetic oceanographic setting in the NW Mediterranean Sea. Here we assess the spatial and temporal variability in abundance, diversity and community structure of the suprabenthic peracarid assemblages in this region and examine this variability in relation to the natural and anthropogenic (trawling fisheries) disturbance regimes. The sampling was conducted between March 2003 and May 2004 in three main fishing grounds, the canyon head (average depth: 490 m), the canyon wall (average depth: 550 m) and the eastern adjacent slope (average depth: 820 m), as well as in two non-exploited areas in the western (at 900 m depth) and eastern (at 1500 m depth) slope near the canyon mouth. A total of 138 species were identified, with amphipods being the most speciose and abundant group, followed by mysids in terms of abundance. Our results show high spatial and temporal variability in suprabenthic assemblages. Densities were higher in the canyon head and western slope, which appear to be the preferential routes for water masses and particle fluxes in months of flood events, and other energetic processes. In the canyon head, where periodic erosion processes are more active, low diversity, high dominance and higher turnover (β-diversity) were observed, apparently coupled with significant temporal fluctuations in the densities of the highly motile component of suprabenthos (mysids, predatory and scavenging amphipods). In the sedimentary more stable eastern slope, high diversity values were observed, accompanied by a higher relative contribution of the less motile groups (i.e. amphipods, most isopods, cumaceans). These groups have a closer interaction with the sediment where they exploit different food sources and are more susceptible to physical disturbance. Temporal variability in their diversity may be related to changes in food quality rather than quantity. In the

  8. The Nordic WOCE trawl-resistant ADCP system

    SciTech Connect

    Osterhus, S.; Hansen, B.

    1995-09-01

    In the Nordic WOCE programme 10 Acoustic Doppler Current Profilers (ADCP`s) will be deployed between Greenland and Scotland. Three of these deployments will be in very heavily fished areas, and a special system has been developed to reduce the risk of interaction between the rig and fishing gear. The system consists of a buoyant instrument package and a protecting platform which will remain on the bottom. The instrument package is a stainless steel frame containing a 150 kHz RDI ADCP with a 90{degree} adapter, an acoustic release, an ARGOS transmitter and sufficient flotation to give the instrument pacakge a net buoyancy of 180 kg. The protecting platform has the form of a truncated pyramid with sides sloping 45{degree} made of steel. During operation the instrument package is attached to the protecting frame by rods in the two ends around which the instrument package may rotate freely. If the system is turned upside down, the instrument package is designed to turn to an operational orientation and it can be released in this condition. To ensure acceptable tilt and stable bottom conditions a deployment frame has been developed with tiltmeter and video camera attached. A prototype of the system was deployed in October 1994.

  9. An inexpensive bottom water sampler

    NASA Astrophysics Data System (ADS)

    Reed, Allen; Carmichael, Aaron; De Angelis, Marie A.

    1997-05-01

    An inexpensive PVC bottom water sampler for collecting near-bottom water samples at a precise height (0.5 to 2.0 m) above the water/sediment interface is described. The RCD (Reed, Carmichael, de Angelis) bottom water sampler can be used with a standard oceanographic hydrowinch, can be made of readily available material (PVC pipe), costs under $300.00 to build, can be built in under 24 hours, is completely mechanical, and can be modified to fit specific needs. The RCD bottom water sampler was successfully tested in northern California coastal waters at depths up to 1071 m.

  10. Resource partitioning within major bottom fish species in a highly productive upwelling ecosystem

    NASA Astrophysics Data System (ADS)

    Abdellaoui, Souad; El Halouani, Hassan; Tai, Imane; Masski, Hicham

    2017-09-01

    The Saharan Bank (21-26°N) is a wide subtropical continental shelf and a highly productive upwelling ecosystem. The bottom communities are dominated by octopus and sparid fish, which are the main targets of bottom-trawl fishing fleets. To investigate resource partitioning within the bottom fish community, adult fish from 14 of the most abundant species were investigated for stomach content analysis. Samples were collected during two periods: October 2003 and May 2007. The diet of the analysed species showed more variation between periods than between size classes, suggesting that temporal or spatial variability in prey availability appears to play a significant role in their diet. Multivariate analysis and subsequent clustering led to a grouping of the species within five trophic guilds. Two species were fish feeders, and the others mainly fed on benthic invertebrates, where epibenthic crustaceans, lamellibranchs and fish were the most important groups in defining trophic guilds. We found that the studied species had a high rate of overlapping spatial distributions and overlapping trophic niches. In this highly productive upwelling ecosystem, where food resources may not be a limiting factor, inter-specific competition did not appear to be an important factor in structuring bottom fish communities. For the species that showed differences in the proportions of prey categories in comparison with other ecosystems, the rise of the proportion of epibenthic crustaceans in their diet was a common feature; a possible consequence of the benthic productivity of this highly productive upwelling ecosystem.

  11. Vacuum still bottoms viscometer

    SciTech Connect

    Dinsmore, T.V.; Wilson, J.H.

    1985-01-01

    A viscometer system that is capable of measuring VSB viscosity on-line has been designed, constructed, and tested. The viscometer will not only provide continuous on-line measurements for process control purposes, but will also determine viscosity as functions of temperature and shear rate. The latter results may be used to verify design-base information for direct coal liquefaction demonstration plants. The viscosities of Wilsonville samples of VSB and LSRC were determined as functions of shear rate and, in the case of LSRC, temperature. The VSB viscosity was found to be shear-rate sensitive, while the LSRC viscosity was temperature sensitive. A 24-h test run was unsuccessful, apparently because the check valves in the pump plugged; however, all other mechanical, electrical, and electronic equipment operated satisfactorily. The source of the plugging was thought to be degradation products, which should not cause difficulties in the pilot plant where fresh vacuum bottoms feed is always available. In summary, the results obtained in this study indicate that the viscometer system is ready to be transported to a plant such as Wilsonville and operated on-line. 7 figs., 5 tabs.

  12. Beach litter sourcing: A trawl along the Northern Ireland coastline.

    PubMed

    Williams, A T; Randerson, P; Allen, C; Cooper, J A G

    2017-09-15

    Fourteen non-recreational coastal locations in Northern Ireland were investigated as to whether beach litter deposition was related to seasonal or site specific factors. Litter items were counted in 100m width transects and 1km strand-line surveys over a five-season period (autumn to autumn). Survey sites comprised fishing ports; estuarine areas, north (high energy) and east coast (low energy) beaches. Fishing ports accumulated the most litter. In the 100m beach surveys, plastics, string and cord, bottle caps, food items, rope, and drink containers dominated. In strand-line surveys, large plastic pieces were dominant, followed by rope, string and cord, strapping bands (absent on beach surveys), cloth, wood (mainly pallets, fish boxes) and metal items. Multivariate analyses revealed major litter category differences between the ports and all other sites, with a lesser distinction between exposed and estuarine sites. There was no simple coastline trend and no apparent effect of seasonality between samples. Copyright © 2017 Elsevier Ltd. All rights reserved.

  13. Bottom ash boosts poor soil

    SciTech Connect

    Stanley, D.

    1993-04-01

    This article describes agricultural uses of fluidized bed bottom ash residue from burning limestone and coal in electric power generating plants: as a limestone substitute, to increase calcium levels in both soil and plants, and as a gypsom-containing soil amendment. Apples and tomatoes are the crops used. The industrial perspective and other uses of bottom ash are also briefly described.

  14. The effects of trawling, dredging and ocean dumping on the eastern Canadian continental shelf seabed

    NASA Astrophysics Data System (ADS)

    Messieh, S. N.; Rowell, T. W.; Peer, D. L.; Cranford, P. J.

    1991-08-01

    This paper presents an overview of current knowledge on the effects of trawling, dredging and ocean dumping on the eastern Canadian continental shelf seabed. The impact of trawling and dredging for fish and shellfish on marine habitats has recently attracted international attention among fisheries and environmental scientists. In Atlantic Canada, trawling and dredging are the principal methods of harvesting groundfish and scallops and ocean clams, respectively. It is estimated that fish trawlers and scallop dredges have swept tracks, cris-crossing the Canadian continental shelf, approximately 4.3 million km in length in 1985. In the past few years several studies were carried out by scientists from Canada, the United States and Europe to assess the impacts of trawling and dredging but results were inconclusive. Some studies showed physical damage as well as biological effects, whereas others indicated that the adverse effects were not considered to be serious. Fishermen are not the only potential users of the resources of the continental shelf. There is an increasing demand for good-quality sand and gravel aggregate and the ocean seabed is being seen as a possible source. The eastern Canadian continental shelf also exhibits hydrocarbon potential and operational and accidental discharges are an environmental concern. Increased marine transportation and expansion of the fishing fleet have resulted in a greater need for harbour dredging. Dredging and dredge spoil disposal were controlled by the Ocean Dumping Control Act and now the Canadian Environmental Protection Act which places restrictions on the composition of material that can be disposed of in the sea. Nevertheless some harbours contain contaminant concentrations exceeding the maximum allowable limits. It is concluded that the impacts of human activities on the continental shelf seabed environment are inevitable and the long-term effects, while difficult to determine, must be assessed. The sub-lethal effects

  15. Quantifying the Escape Mortality of Trawl Caught Antarctic Krill (Euphausia superba).

    PubMed

    Krafft, Bjørn A; Krag, Ludvig A; Engås, Arill; Nordrum, Sigve; Bruheim, Inge; Herrmann, Bent

    2016-01-01

    Antarctic krill (Euphausia superba) is an abundant fishery resource, the harvest levels of which are expected to increase. However, many of the length classes of krill can escape through commonly used commercial trawl mesh sizes. A vital component of the overall management of a fishery is to estimate the total fishing mortality and quantify the mortality rate of individuals that escape from fishing gear. The methods for determining fishing mortality in krill are still poorly developed. We used a covered codend sampling technique followed by onboard observations made in holding tanks to monitor mortality rates of escaped krill. Haul duration, hydrological conditions, maximum fishing depth and catch composition all had no significant effect on mortality of krill escaping 16 mm mesh size nets, nor was any further mortality associated with the holding tank conditions. A non- parametric Kaplan-Meier analysis was used to model the relationship between mortality rates of escapees and time. There was a weak tendency, though not significant, for smaller individuals to suffer higher mortality than larger individuals. The mortality of krill escaping the trawl nets in our study was 4.4 ± 4.4%, suggesting that krill are fairly tolerant of the capture-and-escape process in trawls.

  16. Effect of Codend Circumference on the Size Selection of Square-Mesh Codends in Trawl Fisheries.

    PubMed

    Sala, Antonello; Herrmann, Bent; De Carlo, Francesco; Lucchetti, Alessandro; Brčić, Jure

    2016-01-01

    It is well established that increasing mesh number in the circumference of a diamond-mesh trawl codend can reduce size selection for round fish, whereas selection for flat fish species is unaffected. This effect has also been documented in Mediterranean trawl fisheries. In contrast, no information is available with regard to the effect of increasing mesh number in the circumference of square-mesh codends on the size selection of round fish and flat fish species. A field study was devised to bridge this gap and formulate proposals aimed at improving trawl fishery management. Size selection data were collected for a round fish species, red mullet (Mullus barbatus), and two flat fish species, Mediterranean scaldfish (Arnoglossus laterna) and solenette (Buglossidium luteum). Fishing trials were conducted in the Adriatic Sea (Central Mediterranean) using three square-mesh codends that differed only in mesh number around the circumference. Results demonstrated that increasing the number of meshes from 107 to 213 reduced the 50% retention length (L50) for red mullet by 2.5 cm but did not affect size selection for the two flat fish species. In some fisheries, regulatory provisions regarding the number of meshes in the circumference should therefore be carefully considered both for diamond- and square-mesh codends.

  17. Identification and evaluation of shark bycatch in Georgia's commercial shrimp trawl fishery with implications for management

    USGS Publications Warehouse

    Belcher, C.N.; Jennings, C.A.

    2011-01-01

    Many US states have recreational and commercial fisheries that occur in nursery areas occupied by subadult sharks and can potentially affect their survival. Georgia is one of few US states without a directed commercial shark fishery, but the state has a large, nearshore penaeid shrimp trawl fishery in which small sharks occur as bycatch. During our 1995–1998 investigation of bycatch in fishery-dependent sampling events, 34% of 127 trawls contained sharks. This bycatch totalled 217 individuals from six species, with Atlantic sharpnose shark, Rhizoprionodon terraenovae (Richardson), the most common and finetooth shark, Carcharhinus isodon (Müller & Henle) and spinner shark, Carcharhinus brevipinna (Müller & Henle), the least common. The highest catch rates for sharks occurred during June and July and coincided with the peak months of the pupping season for many species. Trawl tow speed and tow time did not significantly influence catch rates for shark species. Gear configurations [net type, turtle excluder device (TED), bycatch reduction device] affected catch rates for shark species. Results of this study indicate gear restrictions, a delayed season opening, or reduced bar spacing on TEDs may reduce shark bycatch in this fishery.

  18. Quantifying the Escape Mortality of Trawl Caught Antarctic Krill (Euphausia superba)

    PubMed Central

    Krafft, Bjørn A.; Krag, Ludvig A.; Engås, Arill; Nordrum, Sigve; Bruheim, Inge; Herrmann, Bent

    2016-01-01

    Antarctic krill (Euphausia superba) is an abundant fishery resource, the harvest levels of which are expected to increase. However, many of the length classes of krill can escape through commonly used commercial trawl mesh sizes. A vital component of the overall management of a fishery is to estimate the total fishing mortality and quantify the mortality rate of individuals that escape from fishing gear. The methods for determining fishing mortality in krill are still poorly developed. We used a covered codend sampling technique followed by onboard observations made in holding tanks to monitor mortality rates of escaped krill. Haul duration, hydrological conditions, maximum fishing depth and catch composition all had no significant effect on mortality of krill escaping 16 mm mesh size nets, nor was any further mortality associated with the holding tank conditions. A non- parametric Kaplan-Meier analysis was used to model the relationship between mortality rates of escapees and time. There was a weak tendency, though not significant, for smaller individuals to suffer higher mortality than larger individuals. The mortality of krill escaping the trawl nets in our study was 4.4 ± 4.4%, suggesting that krill are fairly tolerant of the capture-and-escape process in trawls. PMID:27622510

  19. Effect of Codend Circumference on the Size Selection of Square-Mesh Codends in Trawl Fisheries

    PubMed Central

    De Carlo, Francesco; Lucchetti, Alessandro

    2016-01-01

    It is well established that increasing mesh number in the circumference of a diamond-mesh trawl codend can reduce size selection for round fish, whereas selection for flat fish species is unaffected. This effect has also been documented in Mediterranean trawl fisheries. In contrast, no information is available with regard to the effect of increasing mesh number in the circumference of square-mesh codends on the size selection of round fish and flat fish species. A field study was devised to bridge this gap and formulate proposals aimed at improving trawl fishery management. Size selection data were collected for a round fish species, red mullet (Mullus barbatus), and two flat fish species, Mediterranean scaldfish (Arnoglossus laterna) and solenette (Buglossidium luteum). Fishing trials were conducted in the Adriatic Sea (Central Mediterranean) using three square-mesh codends that differed only in mesh number around the circumference. Results demonstrated that increasing the number of meshes from 107 to 213 reduced the 50% retention length (L50) for red mullet by 2.5 cm but did not affect size selection for the two flat fish species. In some fisheries, regulatory provisions regarding the number of meshes in the circumference should therefore be carefully considered both for diamond- and square-mesh codends. PMID:27472058

  20. Behavioral flexibility of the trawling long-legged bat, Macrophyllum macrophyllum (Phyllostomidae)

    PubMed Central

    Weinbeer, Moritz; Kalko, Elisabeth K. V.; Jung, Kirsten

    2013-01-01

    We assessed the behavioral flexibility of the trawling long-legged bat, Macrophyllum macrophyllum (Phyllostomidae) in flight cage experiments by exposing it to prey suspended from nylon threads in the air and to food placed onto the water surface at varying distances to clutter-producing background (water plants). The bat revealed flexibility in foraging mode and caught prey in the air (aerial hawking) and from the water surface (trawling). M. macrophyllum was constrained in finding food very near to and within clutter. As echolocation was the prime sensory mode used by M. macrophyllum for detection and localization of food, the bat might have been unable to perceive sufficient information from prey near clutter as background echoes from the water plant increasingly overlapped with echoes from food. The importance of echolocation for foraging is reflected in a stereotypic call pattern of M. macrophyllum that resembles other aerial insectivorous and trawling bats with a pronounced terminal phase (buzz) prior to capture attempts. Our findings contrast studies of other phyllostomid bats that glean prey very near or from vegetation, often using additional sensory cues, such as prey-produced noise, to find food and that lack a terminal phase in echolocation behavior. In M. macrophyllum, acoustic characteristics of its foraging habitat have shaped its sonar system more than phylogeny. PMID:24324442

  1. On effects of trawling, benthos and sampling design.

    PubMed

    Gray, John S; Dayton, Paul; Thrush, Simon; Kaiser, Michel J

    2006-08-01

    The evidence for the wider effects of fishing on the marine ecosystem demands that we incorporate these considerations into our management of human activities. The consequences of the direct physical disturbance of the seabed caused by towed bottom-fishing gear have been studied extensively with over 100 manipulations reported in the peer-reviewed literature. The outcome of these studies varies according to the gear used and the habitat in which it was deployed. This variability in the response of different benthic systems concurs with established theoretical models of the response of community metrics to disturbance. Despite this powerful evidence, a recent FAO report wrongly concludes that the variability in the reported responses to fishing disturbance mean that no firm conclusion as to the effects of fishing disturbance can be made. This thesis is further supported (incorrectly) by the supposition that current benthic sampling methodologies are inadequate to demonstrate the effects of fishing disturbance on benthic systems. The present article addresses these two erroneous conclusions which may confuse non-experts and in particular policy-makers.

  2. Trawls and cooling-water intakes as estuarine fish sampling tools: Comparisons of catch composition, trends in relative abundance, and length selectivity

    NASA Astrophysics Data System (ADS)

    Greenwood, M. F. D.

    2008-01-01

    Fish populations in estuaries are often monitored with traditional sampling gears such as trawls. Trawling is relatively expensive and may be hindered by environmental conditions such as tides and substrates. Power station cooling-water intake screens have been effectively used as estuarine fish sampling devices for many years, but very few quantitative comparisons of intake fish-catch characteristics with samples from other collection methods have been made. Fish collected at the cooling-water intake of a large power station in the lower Forth estuary, UK, were more similar in assemblage composition to fish caught by nearby pelagic trawling than to fish caught by Agassiz (demersal) trawling, mostly because the intake and pelagic-trawl catches were largely composed of clupeids ( Sprattus sprattus and Clupea harengus). The intake catch was typified by pelagic, demersal, and benthic species, however, and was less variable than the catches made by the two trawls. Monthly trends in relative abundance correlated reasonably well between the intake and trawl samples. Fish collected at the intake tended to be significantly smaller than those collected by trawling, which was probably attributable to the intake's smaller mesh size. The study highlighted the utility of a cooling-water intake as an efficient, low-cost fish sampling device, which should be considered as an alternative to trawling as the cost of the latter increases into the future.

  3. Ideal free distribution or dynamic game? An agent-based simulation study of trawling strategies with varying information

    NASA Astrophysics Data System (ADS)

    Beecham, J. A.; Engelhard, G. H.

    2007-10-01

    An ecological economic model of trawling is presented to demonstrate the effect of trawling location choice strategy on net input (rate of economic gain of fish caught per time spent less costs). Fishing location choice is considered to be a dynamic process whereby trawlers chose from among a repertoire of plastic strategies that they modify if their gains fall below a fixed proportion of the mean gains of the fleet as a whole. The distribution of fishing across different areas of a fishery follows an approximate ideal free distribution (IFD) with varying noise due to uncertainty. The least-productive areas are not utilised because initial net input never reaches the mean yield of better areas subject to competitive exploitation. In cases, where there is a weak temporal autocorrelation between fish stocks in a specific location, a plastic strategy of local translocation between trawls mixed with longer-range translocation increases realised input. The trawler can change its translocation strategy in the light of information about recent trawling success compared to its long-term average but, in contrast to predictions of the Marginal Value Theorem (MVT) model, does not know for certain what it will find by moving, so may need to sample new patches. The combination of the two types of translocation mirrored beam-trawling strategies used by the Dutch fleet and the resultant distribution of trawling effort is confirmed by analysis of historical effort distribution of British otter trawling fleets in the North Sea. Fisheries exploitation represents an area where dynamic agent-based adaptive models may be a better representation of the economic dynamics of a fleet than classically inspired optimisation models.

  4. Comment: PAGES: Always Bottom Up

    NASA Astrophysics Data System (ADS)

    Bradley, Raymond

    2004-06-01

    In a recent article titled ``Back to the Future'' (Eos, 16 March, p. 107) L. C. Witton lays out the goals of IGBP-PAGES for the next few years, noting that, ``PAGES is aiming to become a truly bottom-up organization that is driven by the insights of individual scientists....'' In fact, PAGES has always been a truly bottom-up organization, and this statement unfortunately fosters the view that it has been otherwise. Those who promote such a view choose to overlook the countless workshops that PAGES has organized, largely at the suggestion of those ``at the bottom,'' and the numerous publications that have resulted from these meetings.

  5. Bottom Backscattering Strengths Measured in Shallow and Deep Water

    DTIC Science & Technology

    2017-01-18

    Geological Survey (BGS) bottom type (Fig. 5-2) and bottom- grab information (Sect. 5.C) also shown, (No grab information for Sites 7, 13 and 17 other...Space and Naval Warfare Systems Command (SPAWAR) PMW-182. REFERENCES 1. British Geological Survey, “PEACH” (Sheet 56N 10W) and “TIREE” (Sheet 56N...08W) Sea Bed Sediment maps (1: 250 000 Series), National Environmental Resource Council (NERC), 1990 and 1988 (resp.). © NERC. 2. Davis, N.R

  6. Survey of dual frequency identification sonar (DIDSON) applications in fisheries assessment and behavioral studies

    NASA Astrophysics Data System (ADS)

    Belcher, Edward O.

    2005-04-01

    The Dual Frequency Identification Sonar (DIDSON) is a forward-looking sonar that operates in shallow riverine environments with rocky, uneven substrates and near concrete structures such as dams. This allows a number of fisheries applications in environments previously too hostile for reliable sonar operation. Currently 35 DIDSONs have been obtained by 16 groups to accomplish a variety of fish assessment and behavioral studies. This paper surveys the work of these groups and highlights novel assessments allowed by this new acoustic tool. The groups include Alaska Department of Fish and Game, U.S. Fish and Wildlife Service, NOAA, USGS, Bureau of Reclamation, California Department of Water Resources, Pacific Northwest National Laboratories, Nez Perce Tribal Fisheries, Puyallup Tribal Fisheries, Department of Fisheries and Oceans Canada, and Fisheries Engineering Japan. Assessments include: (1) Counting fish migrating up rivers of various sizes, bottom substrates, turbidity, and velocity; (2) Analysis of fish behavior at (A) prototype fish protection devices on dams, (B) irrigation intakes along muddy rivers, (C) intakes of trawl nets; and (3) Detection and measurement of redds in alluvial riverbeds. [Work for the survey supported by Sound Metrics Corp.

  7. Nanoelectronics from the bottom up.

    PubMed

    Lu, Wei; Lieber, Charles M

    2007-11-01

    Electronics obtained through the bottom-up approach of molecular-level control of material composition and structure may lead to devices and fabrication strategies not possible with top-down methods. This review presents a brief summary of bottom-up and hybrid bottom-up/top-down strategies for nanoelectronics with an emphasis on memories based on the crossbar motif. First, we will discuss representative electromechanical and resistance-change memory devices based on carbon nanotube and core-shell nanowire structures, respectively. These device structures show robust switching, promising performance metrics and the potential for terabit-scale density. Second, we will review architectures being developed for circuit-level integration, hybrid crossbar/CMOS circuits and array-based systems, including experimental demonstrations of key concepts such lithography-independent, chemically coded stochastic demultipluxers. Finally, bottom-up fabrication approaches, including the opportunity for assembly of three-dimensional, vertically integrated multifunctional circuits, will be critically discussed.

  8. Prenatal stress from trawl capture affects mothers and neonates: a case study using the southern fiddler ray (Trygonorrhina dumerilii)

    NASA Astrophysics Data System (ADS)

    Guida, L.; Awruch, C.; Walker, T. I.; Reina, R. D.

    2017-04-01

    Assessing fishing effects on chondrichthyan populations has predominantly focused on quantifying mortality rates. Consequently, sub-lethal effects of capture stress on the reproductive capacity of chondrichthyans are largely unknown. We investigated the reproductive consequences of capture on pregnant southern fiddler rays (Trygonorrhina dumerilii) collected from Swan Bay, Australia, in response to laboratory-simulated trawl capture (8 h) followed immediately by air exposure (30 min). Immediately prior to, and for up to 28 days post trawling, all females were measured for body mass (BM), sex steroid concentrations (17-β estradiol, progesterone, testosterone) and granulocyte to lymphocyte (G:L) ratio. At parturition, neonates were measured for total length (TL), BM and G:L ratio. Trawling reduced maternal BM and elevated the G:L ratio for up to 28 days. Trawling did not significantly affect any sex steroid concentrations relative to controls. Neonates from trawled mothers were significantly lower in BM and TL than control animals, and had an elevated G:L ratio. Our results show that capture of pregnant T. dumerilii can influence their reproductive potential and affect the fitness of neonates. We suggest other viviparous species are likely to be similarly affected. Sub-lethal effects of capture, particularly on reproduction, require further study to improve fisheries management and conservation of chondrichthyans.

  9. Photographic evaluation of the impacts of bottom fishing on benthic epifauna

    USGS Publications Warehouse

    Collie, J.S.; Escanero, G.A.; Valentine, P.C.

    2000-01-01

    The gravel sediment habitat on the northern edge of Georges Bank (East coast of North America) is an important nursery area for juvenile fish, and the site of a productive scallop fishery. During two cruises to this area in 1994 we made photographic transects at sites of varying depths that experience varying degrees of disturbance from otter trawling and scallop dredging. Differences between sites were quantified by analyzing videos and still photographs of the sea bottom. Videos were analyzed for sediment types and organism abundance. In the still photos, the percentages of the bottom covered by bushy, plant-like organisms and colonial worm tubes (Filograna implexa) were determined, as was the presence/absence of encrusting bryozoa. Non-colonial organisms were also identified as specifically as possible and sediment type was quantified. Significant differences between disturbed and undisturbed areas were found for the variables measured in the still photos; colonial epifaunal species were conspicuously less abundant at disturbed sites. Results from the videos and still photos were generally consistent although less detail was visible in the videos. Emergent colonial epifauna provide a complex habitat for shrimp, polychaetes, brittle stars and small fish at undisturbed sites. Bottom fishing removes this epifauna, thereby reducing the complexity and species diversity of the benthic community. (C) 2000 International Council for the Exploration of the Sea.

  10. Intercalibration of research survey vessels on Lake Erie

    USGS Publications Warehouse

    Tyson, J.T.; Johnson, T.B.; Knight, C.T.; Bur, M.T.

    2006-01-01

    Fish abundance indices obtained from annual research trawl surveys are an integral part of fisheries stock assessment and management in the Great Lakes. It is difficult, however, to administer trawl surveys using a single vessel-gear combination owing to the large size of these systems, the jurisdictional boundaries that bisect the Great Lakes, and changes in vessels as a result of fleet replacement. When trawl surveys are administered by multiple vessel-gear combinations, systematic error may be introduced in combining catch-per-unit-effort (CPUE) data across vessels. This bias is associated with relative differences in catchability among vessel-gear combinations. In Lake Erie, five different research vessels conduct seasonal trawl surveys in the western half of the lake. To eliminate this systematic bias, the Lake Erie agencies conducted a side-by-side trawling experiment in 2003 to develop correction factors for CPUE data associated with different vessel-gear combinations. Correcting for systematic bias in CPUE data should lead to more accurate and comparable estimates of species density and biomass. We estimated correction factors for the 10 most commonly collected species age-groups for each vessel during the experiment. Most of the correction factors (70%) ranged from 0.5 to 2.0, indicating that the systematic bias associated with different vessel-gear combinations was not large. Differences in CPUE were most evident for vessels using different sampling gears, although significant differences also existed for vessels using the same gears. These results suggest that standardizing gear is important for multiple-vessel surveys, but there will still be significant differences in catchability stemming from the vessel effects and agencies must correct for this. With standardized estimates of CPUE, the Lake Erie agencies will have the ability to directly compare and combine time series for species abundance. ?? Copyright by the American Fisheries Society 2006.

  11. Demography of a deep-sea lantern shark (Etmopterus spinax) caught in trawl fisheries of the northeastern Atlantic: Application of Leslie matrices with incorporated uncertainties

    NASA Astrophysics Data System (ADS)

    Coelho, Rui; Alpizar-Jara, Russell; Erzini, Karim

    2015-05-01

    The deep-sea lantern shark Etmopterus spinax occurs in the northeast Atlantic on or near the bottoms of the outer continental shelves and slopes, and is regularly captured as bycatch in deep-water commercial fisheries. Given the lack of knowledge on the impacts of fisheries on this species, a demographic analysis using age-based Leslie matrices was carried out. Given the uncertainties in the mortality estimates and in the available life history parameters, several different scenarios, some incorporating stochasticity in the life history parameters (using Monte Carlo simulation), were analyzed. If only natural mortality were considered, even after introducing uncertainties in all parameters, the estimated population growth rate (λ) suggested an increasing population. However, if fishing mortality from trawl fisheries is considered, the estimates of λ either indicated increasing or declining populations. In these latter cases, the uncertainties in the species reproductive cycle seemed to be particularly relevant, as a 2-year reproductive cycle indicated a stable population, while a longer (3-year cycle) indicated a declining population. The estimated matrix elasticities were in general higher for the survivorship parameters of the younger age classes and tended to decrease for the older ages. This highlights the susceptibility of this deep-sea squaloid to increasing fishing mortality, emphasizing that even though this is a small-sized species, it shows population dynamics patterns more typical of the larger-sized and in general more vulnerable species.

  12. Methods of analysis by the U.S. Geological Survey National Water Quality Laboratory; determination of semivolatile organic compounds in bottom sediment by solvent extraction, gel permeation chromatographic fractionation, and capillary-column gas chromatography/mass spectrometry

    USGS Publications Warehouse

    Furlong, E.T.; Vaught, D.G.; Merten, L.M.; Foreman, W.T.; Gates, Paul M.

    1996-01-01

    A method for the determination of 79 semivolatile organic compounds (SOCs) and 4 surrogate compounds in soils and bottom sediment is described. The SOCs are extracted from bottom sediment by solvent extraction, followed by partial isolation using high-performance gel permeation chromatography (GPC). The SOCs then are qualitatively identified and quantitative concentrations determined by capillary-column gas chromatography/mass spectrometry (GC/MS). This method also is designed for an optional simultaneous isolation of polychlorinated biphenyls (PCBs) and organochlorine (OC) insecticides, including toxaphene. When OCs and PCBs are determined, an additional alumina- over-silica column chromatography step follows GPC cleanup, and quantitation is by dual capillary- column gas chromatography with electron-capture detection (GC/ECD). Bottom-sediment samples are centrifuged to remove excess water and extracted overnight with dichloromethane. The extract is concentrated, centrifuged, and then filtered through a 0.2-micrometer polytetrafluoro-ethylene syringe filter. Two aliquots of the sample extract then are quantitatively injected onto two polystyrene- divinylbenzene GPC columns connected in series. The SOCs are eluted with dichloromethane, a fraction containing the SOCs is collected, and some coextracted interferences, including elemental sulfur, are separated and discarded. The SOC-containing GPC fraction then is analyzed by GC/MS. When desired, a second aliquot from GPC is further processed for OCs and PCBs by combined alumina-over-silica column chromatography. The two fractions produced in this cleanup then are analyzed by GC/ECD. This report fully describes and is limited to the determination of SOCs by GC/MS.

  13. Performance Prediction Model for Bottom Bounce Operation.

    DTIC Science & Technology

    ACOUSTIC ATTENUATION, *BOTTOM LOSS, *BOTTOM BOUNCE , PERFORMANCE(ENGINEERING), SIGNAL TO NOISE RATIO, ACOUSTIC DETECTION, MATHEMATICAL PREDICTION, COMPUTER APPLICATIONS, RAY TRACING, REVERBERATION, AMBIENT NOISE, SONAR.

  14. 50 CFR Figure 5 to Part 679 - Kodiak Island Type 1, 2, and 3 Nonpelagic Trawl Closure Status and Marmot Bay Tanner Crab...

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 50 Wildlife and Fisheries 13 2014-10-01 2014-10-01 false Kodiak Island Type 1, 2, and 3 Nonpelagic Trawl Closure Status and Marmot Bay Tanner Crab Protection Area 5 Figure 5 to Part 679 Wildlife and... to Part 679—Kodiak Island Type 1, 2, and 3 Nonpelagic Trawl Closure Status and Marmot Bay Tanner Crab...

  15. Flexible echolocation behavior of trawling bats during approach of continuous or transient prey cues

    PubMed Central

    Übernickel, Kirstin; Tschapka, Marco; Kalko, Elisabeth K. V.

    2013-01-01

    Trawling bats use echolocation not only to detect and classify acoustically continuous cues originated from insects at and above water surfaces, but also to detect small water-dwelling prey items breaking the water surface for a very short time, producing only transient cues to be perceived acoustically. Generally, bats need to adjust their echolocation behavior to the specific task on hand, and because of the diversity of prey cues they use in hunting, trawling bats should be highly flexible in their echolocation behavior. We studied the adaptations in the behavior of Noctilio leporinus when approaching either a continuous cue or a transient cue that disappeared during the approach of the bat. Normally the bats reacted by dipping their feet in the water at the cue location. We found that the bats typically started to adapt their calling behavior at approximately 410 ms before prey contact in continuous cue trials, but were also able to adapt their approach behavior to stimuli onsets as short as 177 ms before contact, within a minimum reaction time of 50.9 ms in response to transient cues. In both tasks the approach phase ended between 32 and 53 ms before prey contact. Call emission always continued after the end of the approach phase until around prey contact. In some failed capture attempts, call emission did not cease at all after prey contact. Probably bats used spatial memory to dip at the original location of the transient cue after its disappearance. The duration of the pointed dips was significantly longer in transient cue trials than in continuous cue trials. Our results suggest that trawling bats possess the ability to modify their generally rather stereotyped echolocation behavior during approaches within very short reaction times depending on the sensory information available. PMID:23675352

  16. Consistency of Bottom Fish Communities in the Beaufort Sea Within and Between Years

    NASA Astrophysics Data System (ADS)

    Norcross, B.; Holladay, B.

    2016-02-01

    Fish communities in the Arctic may be indicators of change due to climate and oil and gas exploration. An initial benchmark is generally established by sampling a set of sites in multiple years sequentially to estimate interannual variability. Standard practice is to conduct one trawl haul per station. Establishing the annual frequency of sampling and minimum number of hauls per station necessary to detect changes in demersal fish communities is essential to designing a monitoring program. Using small bottom trawls, we assessed interannual variability of bottom fish communities between 2013 and 2014 in the eastern US Beaufort Sea at eight depths 20-1000 m on each of four transects. In 2014, to determine if one haul per station was representative of a site, replicate hauls were made at stations along one transect at the US-Canada border. The similarity among replicate hauls within a single year was excellent, indicating that one haul per station was representative of fish communities. There were distinctly different bottom fish communities on the Beaufort Sea shelf (20-100 m) and slope (200-1000 m). Shelf communities had higher abundances of smaller fishes; whereas slope communities had fewer, but larger, individuals. There was no change in fish abundance between years, but there was interannual variability in the biomass of fish communities on the slope. However, as few fishes were captured at deep stations, the difference between catching and not catching a single large heavy fish affected relative biomass significantly, which may distort the conclusion of interannual variability. Furthermore, these replicate hauls occurred in the eastern Beaufort Sea, which appears to have fewer fish species and in lower abundance than the western Beaufort Sea. The similarity within replicates may not be as striking in a more diverse environment, however this study shows that in this region of the Arctic, it is likely sufficient to forego replicate sampling at a station in one

  17. Integrating the provision of ecosystem services and trawl fisheries for the management of the marine environment.

    PubMed

    Muntadas, Alba; de Juan, Silvia; Demestre, Montserrat

    2015-02-15

    The species interaction and their biological traits (BT) determine the function of benthic communities and, hence, the delivery of ecosystem services. Therefore, disturbance of benthic communities by trawling may compromise ecosystem service delivery, including fisheries' catches. In this work, we explore 1) the impact of trawling activities on benthic functional components (after the BTA approach) and 2) how trawling impact may affect the ecosystem services delivered by benthic communities. To this aim, we assessed the provision of ecosystem services by adopting the concept of Ecosystem Service Providers (ESP), i.e. ecological units that perform ecosystem functions that will ultimately deliver ecosystem services. We studied thirteen sites subjected to different levels of fishing effort in the Mediterranean. From a range of environmental variables included in the study, we found ESPs to be mainly affected by fishing effort and grain size. Our results suggested that habitat type has significant effects on the distribution of ESPs and this natural variability influences ESP response to trawling at a specific site. In order to summarize the complex relationships between human uses, ecosystem components and the demand for ecosystem services in trawling grounds, we adapted a DPSIR (Drivers-Pressures-State Change-Impact-Response) framework to the study area, emphasizing the role of society as Drivers of change and actors demanding management Responses. This integrative framework aims to inform managers about the interactions between all the elements involved in the management of trawling grounds, highlighting the need for an integrated approach in order to ensure ecosystem service provision.

  18. Partitioning the contributions of mega-, macro- and meiofauna to benthic metabolism on the upper continental slope of New Zealand: Potential links with environmental factors and trawling intensity

    NASA Astrophysics Data System (ADS)

    Leduc, Daniel; Pilditch, Conrad A.; Nodder, Scott D.

    2016-02-01

    Understanding and predicting change in deep-sea benthic ecosystem function remains a major challenge. Here, we conducted analyses combining data on the abundance and biomass of benthic fauna and sediment community oxygen consumption (SCOC) on New Zealand's continental margin to estimate and compare the contributions of meio-, macro-, and megafauna to total benthic metabolism and identify potential links with environmental factors and trawling intensity. We focussed on two regions in close proximity-the high surface primary productivity Chatham Rise and low surface productivity Challenger Plateau. Mean megafauna biomass was twenty times greater on Chatham Rise than Challenger Plateau, likely reflecting differences in food supply between the two regions; this contrast in megafaunal biomass was mainly due to differences in mean body weight rather than abundance. Meio- and macrofauna made similar contributions to SCOC and together accounted for 12% of benthic metabolism on average. In contrast, the estimated contribution of megafauna never exceeded 1.5%. Significant positive correlations between faunal respiration and food availability indicate a link between food supply and benthic community function. Our analyses also show that fauna made a greater contribution to SCOC in conditions of high food availability, and that microorganisms (i.e., the proportion of SCOC not accounted for by the fauna) tended to be more dominant at sites with low food availability. These findings provide support for the concept that large organisms are more strongly affected by a reduction in food resources than small organisms, which in turn underlies one of the most widely described patterns in the deep-sea benthos, i.e., the reduction in organism body size with depth. Because metabolism in deep-sea sediments is typically dominated by microorganisms and small fauna, the absence of a relationship between bottom trawling intensity and the respiration of benthic fauna in the present study may

  19. Sensory challenges for trawling bats: Finding transient prey on water surfaces.

    PubMed

    Übernickel, Kirstin; Simon, Ralph; Kalko, Elisabeth K V; Tschapka, Marco

    2016-04-01

    Bats are able to identify obstacles and prey objects based exclusively on acoustic information acquired via echolocation. To assess the echo information potentially available to the trawling bat Noctilio leporinus, prey objects were ensonified with artificial bat calls and deduced echo target strengths (TS) of the reflected signals. The artificial calls consisted either of constant frequency (CF) or frequency modulated (FM) sounds. Detection distances were calculated for call intensities of N. leporinus emitted in the field and in confined space. Measurements of a transient target consisting of a brief water splash and subsequently expanding water ripples revealed that concentrically expanding water ripples can provide sufficiently loud echoes to be detected by trawling bats. Experiments with stationary targets revealed differences in TS depending on the type of signal used (CF or FM). A calculated maximum detection distance between 4.5 and 13.7 m for all measured targets indicates that prey detection in this very loud calling species occurs much earlier than suggested by estimations based on modifications in echolocation or flight behavior.

  20. Comparing Trawl and Creel Fishing for Norway Lobster (Nephrops norvegicus): Biological and Economic Considerations

    PubMed Central

    Leocádio, Ana Maria; Castro, Margarida

    2012-01-01

    This study compares the fishing activity and landings of the trawl and creel fisheries for Norway lobster (Nephrops norvegicus (L.)) off the Portuguese coast, and evaluates the financial viability of two vessels typical of each fleet. Crustacean trawlers are part of an industrial fleet that, besides Nephrops, targets deep water shrimps. Creels are used by a multi-gear, multi-target artisanal fleet, fishing only in areas unavailable to trawlers and, when catching Nephrops, set specifically to target this species. Trawlers have in recent years contributed with 85% of the landings in weight, but only 74% in value (2005–2009 average). Despite smaller landings, the Nephrops creel fishery provides individuals of larger size and in better condition, thereby obtaining higher unit prices. Economic viability was also higher for the creel vessel, with trawling being only viable if major costs (such as labor and fuel) are covered by the revenue from other target species (e.g., the rose shrimp). At present, Nephrops populations on the South and SW coast are subject to intense fishing and to a recovery plan. The possibility of reallocation of some of the fishing effort directed at Nephrops from trawlers to creels is discussed in terms of the conservation of the resource and economic return. PMID:22848357

  1. SEM/EDS and optical microscopy analyses of microplastics in ocean trawl and fish guts.

    PubMed

    Wang, Zhong-Min; Wagner, Jeff; Ghosal, Sutapa; Bedi, Gagandeep; Wall, Stephen

    2017-12-15

    Microplastic particles from Atlantic and Pacific Ocean trawls, lab-fed fish guts and ocean fish guts have been characterized using optical microscopy and SEM/EDS in terms of size, morphology, and chemistry. We assessed whether these measurements could serve as a rapid screening process for subsequent identification of the likely microplastic candidates by micro-spectroscopy. Optical microscopy enabled morphological classification of the types of particles or fibers present in the sample, as well as the quantification of particle size ranges and fiber lengths. SEM/EDS analysis was used to rule out non-plastic particles and screen the prepared samples for potential microplastic, based on their element signatures and surface characteristics. Chlorinated plastics such as polyvinyl chloride (PVC) could be easily identified with SEM/EDS due to their unique elemental signatures including chlorine, as could mineral species that are falsely identified as plastics by optical microscopy. Particle morphology determined by optical microscopy and SEM suggests the fish ingested particles contained both degradation fragments from larger plastic pieces and also manufactured microplastics. SEM images of microplastic particle surfaces revealed characteristic cracks consistent with environmental exposure, as well as pigment particles consistent with manufactured materials. Most of the microplastic surfaces in the fish guts and ocean trawls were covered with biofilms, radiolarians, and crustaceans. Many of the fish stomachs contained micro-shell pieces which visually resembled microplastics. Copyright © 2017 Elsevier B.V. All rights reserved.

  2. Building from the Bottom Up

    DTIC Science & Technology

    2003-05-01

    through billions of years of prebiotic and molecular selection and evolution, there are bio-organic by Shuguang Zhang Building from the bottom up... Health , Du Pont-MIT Alliance, and the Whitaker Foundation. I also gratefully acknowledge Intel Corporation Academic Program for the generous donation

  3. "Bottom-up" transparent electrodes.

    PubMed

    Morag, Ahiud; Jelinek, Raz

    2016-11-15

    Transparent electrodes (TEs) have attracted significant scientific, technological, and commercial interest in recent years due to the broad and growing use of such devices in electro-optics, consumer products (touch-screens for example), solar cells, and others. Currently, almost all commercial TEs are fabricated through "top-down" approaches (primarily lithography-based techniques), with indium tin oxide (ITO) as the most common material employed. Several problems are encountered, however, in this field, including the cost and complexity of TE production using top-down technologies, the limited structural flexibility, high-cost of indium, and brittle nature and low transparency in the far-IR spectral region of ITO. Alternative routes based upon bottom-up processes, have recently emerged as viable alternatives for production of TEs. Bottom up technologies are based upon self-assembly of building blocks - atoms, molecules, or nanoparticles - generating thin patterned films that exhibit both electrical conductivity and optical transparency. In this Feature Article we discuss the recent progress in this active and exciting field, including bottom-up TE systems produced from carbon materials (carbon nanotubes, graphene, graphene-oxide), silver, gold, and other metals. The current hurdles encountered for broader use of bottom-up strategies along with their significant potential are analyzed.

  4. Culture from the Bottom Up

    ERIC Educational Resources Information Center

    Atkinson, Dwight; Sohn, Jija

    2013-01-01

    The culture concept has been severely criticized for its top-down nature in TESOL, leading arguably to its falling out of favor in the field. But what of the fact that people do "live culturally" (Ingold, 1994)? This article describes a case study of culture from the bottom up--culture as understood and enacted by its individual users.…

  5. Culture from the Bottom Up

    ERIC Educational Resources Information Center

    Atkinson, Dwight; Sohn, Jija

    2013-01-01

    The culture concept has been severely criticized for its top-down nature in TESOL, leading arguably to its falling out of favor in the field. But what of the fact that people do "live culturally" (Ingold, 1994)? This article describes a case study of culture from the bottom up--culture as understood and enacted by its individual users.…

  6. A Random Layer Model for Reflection from Ocean Bottom Sediments.

    DTIC Science & Technology

    1985-02-08

    R. R. Greene, and J. B . Hersey, "The Estimation of Geo-acoustic Ocean-sediment Parameters from Measured Bottom-loss Data," SAIC Report SAI-83-879...Brekhovskikh, Waves in Layered Media, (Academic Press, New York, 1960), pp. 56-61. 9. J. B . Hersey and M. S. Rutstein, "Reconnaissance Survey of...bottom Reflections Identified as White Ash," Natl. Acad. Sci. Proc. 45, 349-355 (1959). 11. B . C. Heezen, M. Thorpe, and M. Ewing, "The Floors of the

  7. 77 FR 75966 - Control Date for Qualifying Landings History in the Central Gulf of Alaska Trawl Groundfish...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-12-26

    ... Landings History in the Central Gulf of Alaska Trawl Groundfish Fisheries AGENCY: National Marine Fisheries... permit history for an allocation-based management or catch share program in the Central Gulf of Alaska..., so that the full catch history for 2012 may be considered in any such future management actions....

  8. 78 FR 17340 - Control Date for Qualifying Landings History in the Western Gulf of Alaska Trawl Groundfish...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-03-21

    ... Landings History in the Western Gulf of Alaska Trawl Groundfish Fisheries AGENCY: National Marine Fisheries... history for an allocation-based management or catch share program in the Western Gulf of Alaska (GOA... awareness of possible rulemaking and provide notice to the public that any accumulation of landings...

  9. 50 CFR Figure 5 to Part 679 - Kodiak Island Closure Status for Vessels Using Non-pelagic Trawl Gear

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 50 Wildlife and Fisheries 9 2010-10-01 2010-10-01 false Kodiak Island Closure Status for Vessels Using Non-pelagic Trawl Gear 5 Figure 5 to Part 679 Wildlife and Fisheries FISHERY CONSERVATION AND... THE EXCLUSIVE ECONOMIC ZONE OFF ALASKA Pt. 679, Fig. 5 Figure 5 to Part 679—Kodiak Island Closure...

  10. 30 CFR 250.1741 - If I drag a trawl across a site, what requirements must I meet?

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... limits described in paragraph (a) of this section in two directions. (c) You must mark the area to be... shipwreck, and 500 feet from a sensitive biological feature. (g) If you trawl near an active pipeline, you...) Buried active pipelines, First contact the pipeline owner or operator to determine the condition of...

  11. 30 CFR 250.1741 - If I drag a trawl across a site, what requirements must I meet?

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... limits described in paragraph (a) of this section in two directions. (c) You must mark the area to be... shipwreck, and 500 feet from a sensitive biological feature. (g) If you trawl near an active pipeline, you...) Buried active pipelines, First contact the pipeline owner or operator to determine the condition of...

  12. 30 CFR 250.1741 - If I drag a trawl across a site, what requirements must I meet?

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... limits described in paragraph (a) of this section in two directions. (c) You must mark the area to be... shipwreck, and 500 feet from a sensitive biological feature. (g) If you trawl near an active pipeline, you...) Buried active pipelines, First contact the pipeline owner or operator to determine the condition of...

  13. Effects of Modified Handling on the Physiological Stress of Trawled-and-Discarded Yellowfin Bream (Acanthopagrus australis).

    PubMed

    Uhlmann, Sven Sebastian; Broadhurst, Matt Kenyon; Millar, Russell Brian

    2015-01-01

    Modified handling is often claimed to reduce (sub-)lethal impacts among organisms caught-and-released in fisheries. Improving welfare of discarded fish warrants investigation, when their survival is of both economic and ecological importance. In this study, juvenile yellowfin bream (Acanthopagrus australis) were trawled in an Australian penaeid fishery and then discarded after on-board sorting in either dry or water-filled (modified) trays and with delays in starting sorting of either 2 or 15 mins. Blood plasma cortisol, glucose and potassium were sampled immediately from some yellowfin bream, while others were placed into cages (with controls) and sampled after five days. Irrespective of their on-board handling, all trawled fish incurred a relatively high acute stress response (i.e. an increase in Mean ± SE cortisol from a baseline of <4 to 122.0 ± 14.9 ng/mL) that was mostly attributed to the trawling process, and exacerbated by variation in key parameters (low salinity, changes in water temperature and the presence of jellyfish Catostylus mosaicus in catches). When C. mosaicus was present, the potassium concentrations of fish sampled immediately after sorting were significantly elevated, possibly due to nematocyst contact and subsequent inhibition of ion pumps or cytolysis. Stress also increased during handling in response to warmer air temperatures and longer exposure. While most fish had substantially recovered by 120 hours after discarding, deploying selective trawls (to reduce jellyfish) for short periods and then quickly sorting catches in water would benefit discard welfare.

  14. 50 CFR Figure 5 to Part 679 - Kodiak Island Closure Status for Vessels Using Non-pelagic Trawl Gear

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 50 Wildlife and Fisheries 11 2011-10-01 2011-10-01 false Kodiak Island Closure Status for Vessels Using Non-pelagic Trawl Gear 5 Figure 5 to Part 679 Wildlife and Fisheries FISHERY CONSERVATION AND MANAGEMENT, NATIONAL OCEANIC AND ATMOSPHERIC ADMINISTRATION, DEPARTMENT OF COMMERCE (CONTINUED) FISHERIES OF THE EXCLUSIVE ECONOMIC ZONE OFF ALASKA...

  15. 50 CFR Figure 5 to Part 679 - Kodiak Island Closure Status for Vessels Using Non-pelagic Trawl Gear

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 50 Wildlife and Fisheries 13 2012-10-01 2012-10-01 false Kodiak Island Closure Status for Vessels Using Non-pelagic Trawl Gear 5 Figure 5 to Part 679 Wildlife and Fisheries FISHERY CONSERVATION AND MANAGEMENT, NATIONAL OCEANIC AND ATMOSPHERIC ADMINISTRATION, DEPARTMENT OF COMMERCE (CONTINUED) FISHERIES OF THE EXCLUSIVE ECONOMIC ZONE OFF ALASKA...

  16. 50 CFR Figure 5 to Part 679 - Kodiak Island Closure Status for Vessels Using Non-pelagic Trawl Gear

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 50 Wildlife and Fisheries 13 2013-10-01 2013-10-01 false Kodiak Island Closure Status for Vessels Using Non-pelagic Trawl Gear 5 Figure 5 to Part 679 Wildlife and Fisheries FISHERY CONSERVATION AND MANAGEMENT, NATIONAL OCEANIC AND ATMOSPHERIC ADMINISTRATION, DEPARTMENT OF COMMERCE (CONTINUED) FISHERIES OF THE EXCLUSIVE ECONOMIC ZONE OFF ALASKA...

  17. 75 FR 4684 - Fisheries off West Coast States; Pacific Coast Groundfish Fishery; Data Collection for the Trawl...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-01-29

    ... States Marine Fisheries Commission's Pacific Fisheries Information Network (PacFIN) database, NMFS' Northwest Fisheries Science Center's Pacific whiting observer data from NORPAC (a database of North Pacific... trawl- endorsed groundfish limited entry permit database to determine initial allocation of quota...

  18. Chapter A8. Bottom-Material Samples

    USGS Publications Warehouse

    Radtke, Dean B.

    1998-01-01

    The National Field Manual for the Collection of Water-Quality Data(National Field Manual) describes protocols (requirements and recommendations) and provides guidelines for U.S. Geological Survey (USGS) personnel who collect data used to assess the quality of the Nation's surface-water and ground-water resources. This release of Chapter A8 provides guidelines for the equipment and procedures needed to collect and process samples of bottom material for the evaluation of surface-water quality. Each chapter of the National Field Manual is published separately and revised periodically. Newly published and revised chapters are posted on the World Wide Web on the USGS page 'National Field Manual for the Collection of Water-Quality Data.' The URL for this page is http://pubs.water.usgs.gov/twri9A/ (accessed April 2005).

  19. Wire-bottom versus solid-bottom rodent caging issues important to scientists and laboratory animal science specialists.

    PubMed

    Stark, D M

    2001-11-01

    Recent emphasis in the National Research Council's Guide for the Care and Use of Laboratory Animals and by the Association for Assessment and Accreditation of Laboratory Animal Care, International, related to the availability of bedding in rodent cages raises regulatory and accreditation issues in the toxicology-laboratory setting. This article reviews the results of a recent survey of 12 United States-based pharmaceutical and contract toxicology laboratories. The perceived benefits and issues related to the use of wire-bottom and bedded caging for rodent studies are presented. The 1999 survey showed that more than 80% of the rodents in surveyed toxicology facilities were housed in wire-bottom cages. Long-term budget expenses related to supplies and waste disposal are assessed. Considerable short-term and long-term costs to programs would be associated with a change from wire-bottom to solid-bottom caging. A review of the past and recent literature related to animal preferences and cage-associated animal lesions is included. The importance of IACUC review of caging chosen by the investigative staff is emphasized.

  20. Peculiarities of Environment Pollution as a Special Type of Radioactive Waste: Field Means for Comprehensive Characterization of Soil and Bottom Sediments and their Application in the Survey at the Flood plain of Techa River - 13172

    SciTech Connect

    Ivanov, Oleg; Danilovich, Alexey; Potapov, Victor; Stepanov, Vyacheslav; Smirnov, Sergey; Volkovich, Anatoly

    2013-07-01

    Contamination of natural objects - zone alarm fallout, zones and flood plains near production sites (the result of technological accidents and resource extraction) occupy large areas. Large area and volume of contaminated matter, moderate specific activity (as low - medium-level wastes) make such objects specific types of radioactive waste. These objects exist for a long time, now they are characterized by a bound state of nuclides with the matrix. There is no cost-effective ways to remove these waste, the only solution for the rehabilitation of such areas is their isolation and regular monitoring through direct and indirect measurements. The complex of instruments was developed to field mapping of contamination. It consists of a portable spectrometric collimated detector, collimated spectrometric borehole detector, underwater spectrometer detector, spectrometer for field measurements of the specific activity of Sr-90, connected to a portable MCA 'Colibry (Hummingbird)'. The complex was used in settlements of Bryansk region, rivers Techa and Yenisei. The effectiveness of the developed complex considered by the example of characterization of the reservoir 10 (artificial lake) in Techinsky cascade containing a huge amount of radioactive waste. The developed field means for comprehensive characterization of soil and bottom sediments contamination are very effective for mapping and monitoring of environment contamination after accidents. Especially in case of high non-uniformity of fallout and may be very actual in Fukushima area. (authors)

  1. Methods of analysis by the U.S. Geological Survey National Water Quality Laboratory : determination of organochlorine pesticides and polychlorinated biphenyls in bottom and suspended sediment by gas chromatography with electron-capture detection

    USGS Publications Warehouse

    Noriega, Mary C.; Wydoski, Duane S.; Foreman, William T.

    2004-01-01

    A method applicable for the determination of 19 organochlorine (OC) pesticides, including total toxaphene as a complex mixture, and 3 polychlorinated biphenyl (PCB) mixtures as Aroclor equivalents--Aroclor 1016/1242, 1254, and 1260--in soil, aquatic bottom sediment, and suspended sediment is described. Method performance data are presented. The solvent system is designed to extract simultaneously selected OC pesticides and PCBs from the same sample matrix. The compounds are extracted by conventional Soxhlet extraction with dichloromethane, followed by partial isolation using gel permeation chromatography (GPC) to remove inorganic sulfur and large naturally present molecules from the sediment extract. The aliquot of extract collected from the GPC for OCs (OC pesticides and PCBs) is split into two sample fractions by alumina/silica combined-column chromatography, followed by Florisil adsorption chromatography to remove interfering compounds in the second fraction. The OC fractions are analyzed by dual capillary-column gas chromatography with electron-capture detection (GC/ECD). This report is limited to the determination of selected OC pesticides and PCBs by GC/ECD using this method. Interim reporting levels (IRLs) have been set at 0.400 to 3.12 micrograms per kilogram for 18 individual OC pesticides, 200 micrograms per kilogram for toxaphene, and 4.04 to 4.68 micrograms per kilogram for the PCBs, based on a sample size of 25-gram equivalent dry weight. These reporting levels may change following additional determinations of method detection limits.

  2. A Comparison of Fish and Invertebrate Catch from Two Small Demersal Beam Trawls in the Beaufort Sea

    NASA Astrophysics Data System (ADS)

    Edenfield, L.; Iken, K.; Norcross, B.

    2016-02-01

    Both the US and Canada have conducted multi-year sampling of seafloor fauna in the Beaufort Sea using small demersal beam trawls. During the BOEM US-Canada Transboundary Fish and Lower Trophic Communities program 2012-2014, US researchers collected benthic fish and invertebrates from Pt. Barrow to the Mackenzie River mouth and Canadian scientists collected this information in the Beaufort Regional Environmental Assessment from the international border to Amundsen Gulf. Here, we compare the resulting benthic invertebrate and fish communities sampled in 2013 using the US 3-m plumb-staff beam trawl with those obtained from the Canadian beam trawl, which had larger mesh. Samples were collected at 42 locations along 6 shelf-to-slope transects (136.7 °W-146.1°W) at depths ranging from 20 to 1000 m near and west of the Mackenzie River outflow with both beam trawls. Differences in standardized catch per unit effort between gears were examined using nonparametric analyses. Based on our findings, catches between the two beam trawls can be considered indistinguishable in terms of the abundance, biomass, and overall community composition captured. Further analysis revealed that depth was a significant factor in catch composition of benthic fauna. There were no significant differences in fish sizes or taxa captured between the gears. Thus, direct comparisons of data collected from both programs can be made. This information improves our ability to examine fish and benthic invertebrate communities across the entire Beaufort Sea from Pt. Barrow in the west to Amundson Gulf in the east by allowing direct comparison between two distinct research programs.

  3. Mapping of sea bottom topography

    NASA Technical Reports Server (NTRS)

    Calkoen, C. J.; Wensink, G. J.; Hesselmans, G. H. F. M.

    1992-01-01

    Under suitable conditions the bottom topography of shallow seas is visible in remote sensing radar imagery. Two experiments were performed to establish which remote sensing technique or combination yields optimal imaging of bottom topography and which hydro-meteorological conditions are favorable. A further goal is to gain experience with these techniques. Two experiments were performed over an area in the North Sea near the measuring platform Meetpost Noordwijk (MPN). The bottom topography in the test area is dominated by sand waves. The crests of the sand waves are perpendicular to the coast line and the dominating (tidal-)current direction. A 4x4 sq km wide section of the test area was studied in more detail. The first experiment was undertaken on 16 Aug. 1989. During the experiment the following remote sensing instruments were used: Landsat-Thematic Mapper, and NASA/JPL Airborne Imaging Radar (AIR). The hydro-meteorological conditions; current, wind, wave, and air and water temperature were monitored by MPN, a ship of Rijkswaterstaat (the OCTANS), and a pitch-and-roll WAVEC-buoy. The second experiment took place on 12 July 1992. During this experiment data were collected with the NASA/JPL polarimetric synthetic aperture radar (SAR), and a five-band helicopter-borne scatterometer. Again the hydro-meteorological conditions were monitored at MPN and the OCTANS. Furthermore, interferometric radar data were collected.

  4. Using multiple gears to assess acoustic detectability and biomass of fish species in lake superior

    USGS Publications Warehouse

    Yule, D.L.; Adams, J.V.; Stockwell, J.D.; Gorman, O.T.

    2007-01-01

    Recent predator demand and prey supply studies suggest that an annual daytime bottom trawl survey of Lake Superior underestimates prey fish biomass. A multiple-gear (acoustics, bottom trawl, and midwater trawl) nighttime survey has been recommended, but before abandoning a long-term daytime survey the effectiveness of night sampling of important prey species must be verified. We sampled three bottom depths (30, 60, and 120 m) at a Lake Superior site where the fish community included all commercially and ecologically important species. Day and night samples were collected within 48 h at all depths during eight different periods (one new and one full moon period during both early summer and late summer to early fall over 2 years). Biomass of demersal and benthic species was higher in night bottom trawl samples than in day bottom trawl samples. Night acoustic collections showed that pelagic fish typically occupied water cooler than 15°C and light levels less than 0.001 lx. Using biomass in night bottom trawls and acoustic biomass above the bottom trawl path, we calculated an index of acoustic detectability for each species. Ciscoes Coregonus artedi, kiyis C. kiyi, and rainbow smeltOsmerus mordax left the bottom at night, whereas bloaters C. hoyi stayed nearer the bottom. We compared the biomass of important prey species estimated with two survey types: day bottom trawls and night estimates of the entire water column (bottom trawl biomass plus acoustic biomass). The biomass of large ciscoes (>200 mm) was significantly greater when measured at night than when measured during daylight, but the differences for other sizes of important species did not vary significantly by survey type. Nighttime of late summer is a period when conditions for biomass estimation are largely invariant, and all important prey species can be sampled using a multiple-gear approach.

  5. Measurements by Ocean Bottom Gravimeter at Harima-nada in Seto Inland Sea, Japan

    NASA Astrophysics Data System (ADS)

    Joshima, Masato; Ishihara, Takemi; Koizumi, Kin-Ichiro; Seama, Nobukazu; Oshida, Atsushi; Fujimoto, Hiromi; Kanazawa, Toshihiko

    Gravity measurements on the sea bottom using an ocean bottom gravimeter(OBG) and a small survey vessel of 8.5 tons were performed at Harima-nada, in the Seto Inland Sea, Japan. Measurements at one bottom station were completed in about 30 minutes including 2 mile transit from the previous station, and 23 new data were obtained during 4 days. The measurement noise on the shallow sea-bottom was reduced considerably by attaching an anchor to the rope between the deployed ocean bottom gravimeter and the ship, and by keeping the ship almost fixed to the deployed anchor. The measurement accuracy is better than 0.005 mgal at the base station and is better than 0.05 mgal for the sea bottom measurements with the anchor. The new measurements combined with old data revealed the presence of high gravity anomaly zone running in Harima-nada sub-parallel to the Median Tectonic Line.

  6. Common Dolphin (Delphinus delphis) Bycatch in New Zealand Commercial Trawl Fisheries

    PubMed Central

    Thompson, Finlay N.; Abraham, Edward R.; Berkenbusch, Katrin

    2013-01-01

    Marine mammals are regularly reported as bycatch in commercial and artisanal fisheries, but data are often insufficient to allow assessment of these incidental mortalities. Observer coverage of the mackerel trawl fishery in New Zealand waters between 1995 and 2011 allowed evaluation of common dolphin Delphinus delphis bycatch on the North Island west coast, where this species is the most frequently caught cetacean. Observer data were used to develop a statistical model to estimate total captures and explore covariates related to captures. A two-stage Bayesian hurdle model was used, with a logistic generalised linear model predicting whether any common dolphin captures occurred on a given tow of the net, and a zero-truncated Poisson distribution to estimate the number of dolphin captures, given that there was a capture event. Over the 16-year study period, there were 119 common dolphin captures reported on 4299 observed tows. Capture events frequently involved more than one individual, with a maximum of nine common dolphin observed caught in a single tow. There was a peak of 141 estimated common dolphin captures (95% c.i.: 56 to 276; 6.27 captures per 100 tows) in 2002–03, following the marked expansion in annual effort in this fishery to over 2000 tows. Subsequently, the number of captures fluctuated although fishing effort remained relatively high. Of the observed capture events, 60% were during trawls where the top of the net (headline) was <40 m below the surface, and the model determined that this covariate best explained common dolphin captures. Increasing headline depth by 21 m would halve the probability of a dolphin capture event on a tow. While lack of abundance data prevents assessment of the impact of these mortalities on the local common dolphin population, a clear recommendation from this study is the increasing of headline depth to reduce common dolphin captures. PMID:23717614

  7. Common dolphin (Delphinus delphis) bycatch in New Zealand commercial trawl fisheries.

    PubMed

    Thompson, Finlay N; Abraham, Edward R; Berkenbusch, Katrin

    2013-01-01

    Marine mammals are regularly reported as bycatch in commercial and artisanal fisheries, but data are often insufficient to allow assessment of these incidental mortalities. Observer coverage of the mackerel trawl fishery in New Zealand waters between 1995 and 2011 allowed evaluation of common dolphin Delphinus delphis bycatch on the North Island west coast, where this species is the most frequently caught cetacean. Observer data were used to develop a statistical model to estimate total captures and explore covariates related to captures. A two-stage Bayesian hurdle model was used, with a logistic generalised linear model predicting whether any common dolphin captures occurred on a given tow of the net, and a zero-truncated Poisson distribution to estimate the number of dolphin captures, given that there was a capture event. Over the 16-year study period, there were 119 common dolphin captures reported on 4299 observed tows. Capture events frequently involved more than one individual, with a maximum of nine common dolphin observed caught in a single tow. There was a peak of 141 estimated common dolphin captures (95% c.i.: 56 to 276; 6.27 captures per 100 tows) in 2002-03, following the marked expansion in annual effort in this fishery to over 2000 tows. Subsequently, the number of captures fluctuated although fishing effort remained relatively high. Of the observed capture events, 60% were during trawls where the top of the net (headline) was <40 m below the surface, and the model determined that this covariate best explained common dolphin captures. Increasing headline depth by 21 m would halve the probability of a dolphin capture event on a tow. While lack of abundance data prevents assessment of the impact of these mortalities on the local common dolphin population, a clear recommendation from this study is the increasing of headline depth to reduce common dolphin captures.

  8. Strategic Plan for the U.S. Geological Survey. Status and Trends of Biological Resources Program: 2004-2009

    DTIC Science & Technology

    2004-01-01

    Lakes Science animals are being developed to better understand their move- Center captures fish in a bottom trawl on Lake Huron . USGS ments and...Fish and Wildlife Improvement Act, 1978: Endangered Species Act, 1973; Marine Mammal Protection Act, 1972: Great Lakes Fishery Act, ’For example...resources; (2) Great Lakes fish stock partnership begin to emerge. assessments to satisfy international agreements and Native American treaty obligations

  9. Morpho-Bathymetry of the Specchio di Venere Crater Lake, Pantelleria Island, Italy: Integration of GPS Surveys with non-GPS Data and Evidence of Sedimentary Control on Lake Bottom Topography

    NASA Astrophysics Data System (ADS)

    Madonia, P.; Cangemi, M.; Bellanca, A.; D'Alessandro, W.; Neri, R.; Failla, A.

    2009-12-01

    Pantelleria is a Pleistocene strato-volcano island located in the Sicily Channel Rift Zone, about 100 km south-west of Sicily and 70 km north-east of Tunisia. Specchio di Venere is an endorheic lake located inside a calderic depression (Caldera Cinque Denti), showing a sub-circular shape (being ca 450 m long and ca 350 m wide) and a maximum depth of 12.5 m, with steeper slopes in its north-eastern area. The south-western sector of the lake is characterized by a diffused hydrothermal activity (low temperature fumarole vents and hydrothermal springs). Several morpho-bathymetric surveys, based on both direct sounding and echo-sounding methods, have been carried out into the lake, using different techniques for the planar positioning of the measure points: takeometers, metric ropes tightened on the opposite sides of the lake and, finally, differential single frequency GPS. A comparison between the different surveys clearly indicates that the low number of bathymetric measures carried out in pre-GPS surveys, due to difficulties of a precise and fast positioning of the measure points, heavily influenced the map of the lake floor. In particular, the interpretation of the lake floor morphology was the result of the archetypal idea of a lake, with parallel, iso-spaced bathymetric curves, merely reproducing the shape of the lake shoreline. After the advent of GPS techniques, in the framework of a research project financed by the Italian Civil Defence Department, a new survey was carried out on May 2007, further integrated by another measuring campaign on May 2009. The new bathymetric map, based on 445 depth points, not aligned along transects to avoid the generation of pseudo-structures due to the geometry of the measure points, revealed a quite different structure of the low-depth (maximum 2 m) south-western sector of the lake, whose morphology is probably to be related to interaction of the hydrothermal vent field with sedimentary processes, resulting in the formation of

  10. 77 FR 29905 - Sea Turtle Conservation; Shrimp and Summer Flounder Trawling Requirements

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-05-21

    ... Big Boy TED for use in the shrimp fisheries; using three large TED and Boone Wedge Cut escape openings... turtle TED testing, the Boone Big Boy TED was tested in a bottom-opening configuration. Sinkey Boone...'' (55 FR 41092, October 9, 1990). The test results for the bottom-opening Boone Big Boy TED at...

  11. 50 CFR Table 2 (north) to Part 660... - Non-Trawl Rockfish Conservation Areas and Trip Limits for Limited Entry Fixed Gear North of 40°10...

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 50 Wildlife and Fisheries 13 2013-10-01 2013-10-01 false Non-Trawl Rockfish Conservation Areas and Trip Limits for Limited Entry Fixed Gear North of 40°10â² N. Lat. 2 Table 2 (North) to Part 660... Table 2 (North) to Part 660, Subpart E—Non-Trawl Rockfish Conservation Areas and Trip Limits for Limited...

  12. 50 CFR Table 1 (north) to Part 660... - Limited Entry Trawl Rockfish Conservation Areas and Landing Allowances for non-IFQ Species and...

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 50 Wildlife and Fisheries 13 2013-10-01 2013-10-01 false Limited Entry Trawl Rockfish Conservation Areas and Landing Allowances for non-IFQ Species and Pacific Whiting North of 40°10â² N. Lat. 1 Table 1... Pt. 660, Subpt. D, Table 1 Table 1 (North) to Part 660, Subpart D—Limited Entry Trawl Rockfish...

  13. 50 CFR Table 1 (north) to Part 660... - Limited Entry Trawl Rockfish Conservation Areas and Landing Allowances for non-IFQ Species and...

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 50 Wildlife and Fisheries 13 2012-10-01 2012-10-01 false Limited Entry Trawl Rockfish Conservation Areas and Landing Allowances for non-IFQ Species and Pacific Whiting North of 40°10â² N. Lat. 1 Table 1... Pt. 660, Subpt. D, Table 1 Table 1 (North) to Part 660, Subpart D—Limited Entry Trawl Rockfish...

  14. 50 CFR Table 1 (south) to Part 660... - Limited Entry Trawl Rockfish Conservation Areas and Landing Allowances for non-IFQ Species and...

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 50 Wildlife and Fisheries 13 2013-10-01 2013-10-01 false Limited Entry Trawl Rockfish Conservation Areas and Landing Allowances for non-IFQ Species and Pacific Whiting South of 40°10â² N. Lat. 1 Table 1... Pt. 660, Subpt. D, Table 1 Table 1 (South) to Part 660, Subpart D—Limited Entry Trawl Rockfish...

  15. 50 CFR Table 2 (south) to Part 660... - Non-Trawl Rockfish Conservation Areas and Trip Limits for Limited Entry Fixed Gear South of 40°10...

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 50 Wildlife and Fisheries 13 2013-10-01 2013-10-01 false Non-Trawl Rockfish Conservation Areas and Trip Limits for Limited Entry Fixed Gear South of 40°10â² N. Lat. 2 Table 2 (South) to Part 660... Table 2 (South) to Part 660, Subpart E—Non-Trawl Rockfish Conservation Areas and Trip Limits for Limited...

  16. 50 CFR Table 1 (north) to Part 660... - Limited Entry Trawl Rockfish Conservation Areas and Landing Allowances for non-IFQ Species and...

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 50 Wildlife and Fisheries 13 2014-10-01 2014-10-01 false Limited Entry Trawl Rockfish Conservation Areas and Landing Allowances for non-IFQ Species and Pacific Whiting North of 40°10â² N. Lat. 1 Table 1... Pt. 660, Subpt. D, Table 1 Table 1 (North) to Part 660, Subpart D—Limited Entry Trawl Rockfish...

  17. 50 CFR Table 2 (south) to Part 660... - Non-Trawl Rockfish Conservation Areas and Trip Limits for Limited Entry Fixed Gear South of 40°10...

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 50 Wildlife and Fisheries 13 2012-10-01 2012-10-01 false Non-Trawl Rockfish Conservation Areas and Trip Limits for Limited Entry Fixed Gear South of 40°10â² N. Lat. 2 Table 2 (South) to Part 660... Table 2 (South) to Part 660, Subpart E—Non-Trawl Rockfish Conservation Areas and Trip Limits for Limited...

  18. 50 CFR Table 1 (south) to Part 660... - Limited Entry Trawl Rockfish Conservation Areas and Landing Allowances for non-IFQ Species and...

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 50 Wildlife and Fisheries 13 2012-10-01 2012-10-01 false Limited Entry Trawl Rockfish Conservation Areas and Landing Allowances for non-IFQ Species and Pacific Whiting South of 40°10â² N. Lat. 1 Table 1... Pt. 660, Subpt. D, Table 1 Table 1 (South) to Part 660, Subpart D—Limited Entry Trawl Rockfish...

  19. 50 CFR Table 1 (south) to Part 660... - Limited Entry Trawl Rockfish Conservation Areas and Landing Allowances for non-IFQ Species and...

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 50 Wildlife and Fisheries 13 2014-10-01 2014-10-01 false Limited Entry Trawl Rockfish Conservation Areas and Landing Allowances for non-IFQ Species and Pacific Whiting South of 40°10â² N. Lat. 1 Table 1... Pt. 660, Subpt. D, Table 1 Table 1 (South) to Part 660, Subpart D—Limited Entry Trawl Rockfish...

  20. 50 CFR Table 2 (north) to Part 660... - Non-Trawl Rockfish Conservation Areas and Trip Limits for Limited Entry Fixed Gear North of 40°10...

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 50 Wildlife and Fisheries 11 2011-10-01 2011-10-01 false Non-Trawl Rockfish Conservation Areas and Trip Limits for Limited Entry Fixed Gear North of 40°10â² N. Lat. 2 Table 2 (North) to Part 660... Table 2 (North) to Part 660, Subpart E—Non-Trawl Rockfish Conservation Areas and Trip Limits for Limited...

  1. 50 CFR Table 2 (north) to Part 660... - Non-Trawl Rockfish Conservation Areas and Trip Limits for Limited Entry Fixed Gear North of 40°10...

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 50 Wildlife and Fisheries 13 2012-10-01 2012-10-01 false Non-Trawl Rockfish Conservation Areas and Trip Limits for Limited Entry Fixed Gear North of 40°10â² N. Lat. 2 Table 2 (North) to Part 660... Table 2 (North) to Part 660, Subpart E—Non-Trawl Rockfish Conservation Areas and Trip Limits for Limited...

  2. 50 CFR Table 2 (south) to Part 660... - Non-Trawl Rockfish Conservation Areas and Trip Limits for Limited Entry Fixed Gear South of 40°10...

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 50 Wildlife and Fisheries 13 2014-10-01 2014-10-01 false Non-Trawl Rockfish Conservation Areas and Trip Limits for Limited Entry Fixed Gear South of 40°10â² N. Lat. 2 Table 2 (South) to Part 660... Table 2 (South) to Part 660, Subpart E—Non-Trawl Rockfish Conservation Areas and Trip Limits for Limited...

  3. 50 CFR Table 2 (north) to Part 660... - Non-Trawl Rockfish Conservation Areas and Trip Limits for Limited Entry Fixed Gear North of 40°10...

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 50 Wildlife and Fisheries 13 2014-10-01 2014-10-01 false Non-Trawl Rockfish Conservation Areas and Trip Limits for Limited Entry Fixed Gear North of 40°10â² N. Lat. 2 Table 2 (North) to Part 660... Table 2 (North) to Part 660, Subpart E—Non-Trawl Rockfish Conservation Areas and Trip Limits for Limited...

  4. Vacuum leak detection for double bottom tanks

    SciTech Connect

    Hagen, T.; Rials, R.

    1995-12-31

    Double bottom tanks offer strong leak detection advantages. By incorporating the use of vacuum detection between the two bottoms, the tank bottoms can be verified leak free after construction and during tank use. Utilizing vacuum leak detection requires special considerations. In 1992 a tank construction company built 10 tanks for an oil company in Ponca City, Oklahoma. Each of these tanks were built with a double bottom. This paper provides insight into the planning, construction and testing of this type of double bottom design.

  5. Density-dependent changes in effective area occupied for sea-bottom-associated marine fishes.

    PubMed

    Thorson, James T; Rindorf, Anna; Gao, Jin; Hanselman, Dana H; Winker, Henning

    2016-10-12

    The spatial distribution of marine fishes can change for many reasons, including density-dependent distributional shifts. Previous studies show mixed support for either the proportional-density model (PDM; no relationship between abundance and area occupied, supported by ideal-free distribution theory) or the basin model (BM; positive abundance-area relationship, supported by density-dependent habitat selection theory). The BM implies that fishes move towards preferred habitat as the population declines. We estimate the average relationship using bottom trawl data for 92 fish species from six marine regions, to determine whether the BM or PDM provides a better description for sea-bottom-associated fishes. We fit a spatio-temporal model and estimate changes in effective area occupied and abundance, and combine results to estimate the average abundance-area relationship as well as variability among taxa and regions. The average relationship is weak but significant (0.6% increase in area for a 10% increase in abundance), whereas only a small proportion of species-region combinations show a negative relationship (i.e. shrinking area when abundance increases). Approximately one-third of combinations (34.6%) are predicted to increase in area more than 1% for every 10% increase in abundance. We therefore infer that population density generally changes faster than effective area occupied during abundance changes. Gadiformes have the strongest estimated relationship (average 1.0% area increase for every 10% abundance increase) followed by Pleuronectiformes and Scorpaeniformes, and the Eastern Bering Sea shows a strong relationship between abundance and area occupied relative to other regions. We conclude that the BM explains a small but important portion of spatial dynamics for sea-bottom-associated fishes, and that many individual populations merit cautious management during population declines, because a compressed range may increase the efficiency of harvest.

  6. Developing Bottom-Up Estimates of Net Carbon Flux Using Survey Data, Remote Sensing, and Economic Modeling: A Case Study for Agricultural Lands in the U.S. Mid-Continental Region

    NASA Astrophysics Data System (ADS)

    West, T. O.; Brandt, C. C.; de La Torre Ugarte, D.; Larson, J. A.; Hellwinkle, C.; Wilson, B.; Marland, G.

    2005-12-01

    Estimates of net carbon-equivalent (Ceq) flux of greenhouse gases to the atmosphere from agricultural lands in the U.S. can be made on an annual basis using existing survey data and remote sensing. Integrating these data sets with the POLYSYS agricultural economics model will allow for estimates of future changes in land use and Ceq emissions that will be associated with carbon management incentives or changes in land-use policies (e.g., Farm Bill and land conservation policies). We are examining carbon sinks and Ceq sources for agricultural lands at the county scale and at a resolution commensurate with remotely sensed land-use data. Carbon sinks and sources include changes in soil carbon stocks; CO2 and N2O emissions associated with the production, transport, and application of agricultural inputs; carbon uptake by crops; and emissions from livestock. This presentation places emphasis on the development and structure of the accounting framework, on the data inputs, and on the mechanisms that will be used to update these inputs on a regular basis. Different accounting methods that may be implemented in the framework to account for either on-site net emissions or first order, upstream emissions associated with new land-use practices will also be discussed. Results are presented for the U.S. mid-continental region in a manner that can be compared to atmospheric top-down modeling approaches for estimating net carbon flux from terrestrial ecosystems.

  7. Interactions between a Trawl Fishery and Spatial Closures for Biodiversity Conservation in the Great Barrier Reef World Heritage Area, Australia

    PubMed Central

    Grech, Alana; Coles, Rob

    2011-01-01

    Background The Queensland East Coast Otter Trawl Fishery (ECOTF) for penaeid shrimp fishes within Australia's Great Barrier Reef World Heritage Area (GBRWHA). The past decade has seen the implementation of conservation and fisheries management strategies to reduce the impact of the ECOTF on the seabed and improve biodiversity conservation. New information from electronic vessel location monitoring systems (VMS) provides an opportunity to review the interactions between the ECOTF and spatial closures for biodiversity conservation. Methodology and Results We used fishing metrics and spatial information on the distribution of closures and modelled VMS data in a geographical information system (GIS) to assess change in effort of the trawl fishery from 2001–2009 and to quantify the exposure of 70 reef, non-reef and deep water bioregions to trawl fishing. The number of trawlers and the number of days fished almost halved between 2001 and 2009 and new spatial closures introduced in 2004 reduced the area zoned available for trawl fishing by 33%. However, we found that there was only a relatively minor change in the spatial footprint of the fishery as a result of new spatial closures. Non-reef bioregions benefited the most from new spatial closures followed by deep and reef bioregions. Conclusions/Significance Although the catch of non target species remains an issue of concern for fisheries management, the small spatial footprint of the ECOTF relative to the size of the GBRWHA means that the impact on benthic habitats is likely to be negligible. The decline in effort as a result of fishing industry structural adjustment, increasing variable costs and business decisions of fishers is likely to continue a trend to fish only in the most productive areas. This will provide protection for most benthic habitats without any further legislative or management intervention. PMID:21695155

  8. Identification and evaluation of shark bycatch in Georgia’s commercial shrimp trawl fishery with implications for management

    USGS Publications Warehouse

    Belcher, C.N.; Jennings, Cecil A.

    2011-01-01

    Many US states have recreational and commercial fisheries that occur in nursery areas occupied by subadult sharks and can potentially affect their survival. Georgia is one of few US states without a directed commercial shark fishery, but the state has a large, nearshore penaeid shrimp trawl fishery in which small sharks occur as bycatch. During our 1995-1998 investigation of bycatch in fishery-dependent sampling events, 34% of 127 trawls contained sharks. This bycatch totalled 217 individuals from six species, with Atlantic sharpnose shark, Rhizoprionodon terraenovae (Richardson), the most common and finetooth shark, Carcharhinus isodon (Müller & Henle) and spinner shark, Carcharhinus brevipinna (Müller & Henle), the least common. The highest catch rates for sharks occurred during June and July and coincided with the peak months of the pupping season for many species. Trawl tow speed and tow time did not significantly influence catch rates for shark species. Gear configurations [net type, turtle excluder device (TED), bycatch reduction device] affected catch rates for shark species. Results of this study indicate gear restrictions, a delayed season opening, or reduced bar spacing on TEDs may reduce shark bycatch in this fishery.

  9. Lifetime measurements for bottom hadrons

    SciTech Connect

    Wolf, G.

    1984-09-01

    The review of lifetime measurements of bottom hadrons begins with a first measurement by JADE, followed by similar measurements by MAC and MKII groups. New MAC data are reviewed based on a total of 75,000 multihadron events taken at a c.m. energy of 29 GeV. According to Monte Carlo calculations, 18% of the lepton candidates stem from charm decay and roughly 30% were misidentified hadrons. DELCO studied electrons obtained from 42,000 multihadron events at 29 GeV. The electrons were identified by means of Cerenkov counters. JADE analayzed 22,000 multihadron events at 35 GeV. Data were analyzed using two methods - one using a sample of b-enriched events, and the other using weighted distributions. The TASSO results were obtained with two different configurations of the detector - one of which used a drift chamber and the other a vertex detector. (LEW)

  10. Charm and bottom semileptonic decays

    NASA Astrophysics Data System (ADS)

    O'donnell, Patrick J.; Turan, Gürsevil

    1997-07-01

    We review the present status of theoretical attempts to calculate the semileptonic charm and bottom decays and then present a calculation of these decays in the light-front frame at the kinematic point q2=0. This allows us to evaluate the form factors at the same value of q2, even though the allowed kinematic ranges for charm and bottom decays are very different. Also, at this kinematic point the decay is given in terms of only one form factor A0(0). For the ratio of the decay rates given by the E653 collaboration we show that the determination of the ratio of the Cabibbo-Kobayashi-Maskawa matrix elements is consistent with that obtained from the unitarity constraint, though a new measurement by the E687 Collaboration is about two standard deviations too high. At present, though, the unitarity method still has greater accuracy. Since comparisons of the semileptonic decays into ρ and either electrons or muons will be available soon from the E791 Fermilab experiment, we also look at the massive muon case. We show that for a range of q2 the SU(3)F symmetry breaking is small even though the contributions of the various helicity amplitudes becomes more complicated. For B decays, the decay B-->K*ll¯ at q2=0 involves an extra form factor coming from the photon contribution and so is not amenable to the same kind of analysis, leaving only the decay B-->K*νν¯ as a possibility. As the mass of the decaying particle increases we note that the SU(3) symmetry becomes badly broken at q2=0.

  11. Properties of the Water Column and Bottom Derived from AVIRIS Data

    NASA Technical Reports Server (NTRS)

    Lee, Zhong-Ping; Carder, Kendall L.; Chen, F. Robert; Peacock, Thomas G.

    2001-01-01

    Using AVIRIS data as an example, we show in this study that the optical properties of the water column and bottom of a large, shallow area can be adequately retrieved using a model-driven optimization technique. The simultaneously derived properties include bottom depth, bottom albedo, and water absorption and backscattering coefficients, which in turn could be used to derive concentrations of chlorophyll, dissolved organic matter, and suspended sediments. The derived bottom depths were compared with a bathymetry chart and a boat survey and were found to agree very well. Also, the derived bottom-albedo image shows clear spatial patterns, with end members consistent with sand and seagrass. The image of absorption and backscattering coefficients indicates that the water is quite horizontally mixed. These results suggest that the model and approach used work very well for the retrieval of sub-surface properties of shallow-water environments even for rather turbid environments like Tampa Bay, Florida.

  12. Properties of the Water Column and Bottom Derived from AVIRIS Data

    NASA Technical Reports Server (NTRS)

    Lee, Zhong-Ping; Carder, Kendall L.; Chen, F. Robert; Peacock, Thomas G.

    2001-01-01

    Using AVIRIS data as an example, we show in this study that the optical properties of the water column and bottom of a large, shallow area can be adequately retrieved using a model-driven optimization technique. The simultaneously derived properties include bottom depth, bottom albedo, and water absorption and backscattering coefficients, which in turn could be used to derive concentrations of chlorophyll, dissolved organic matter, and suspended sediments. The derived bottom depths were compared with a bathymetry chart and a boat survey and were found to agree very well. Also, the derived bottom-albedo image shows clear spatial patterns, with end members consistent with sand and seagrass. The image of absorption and backscattering coefficients indicates that the water is quite horizontally mixed. These results suggest that the model and approach used work very well for the retrieval of sub-surface properties of shallow-water environments even for rather turbid environments like Tampa Bay, Florida.

  13. Inferring Fish Escape Behaviour in Trawls Based on Catch Comparison Data: Model Development and Evaluation Based on Data from Skagerrak, Denmark

    PubMed Central

    Karlsen, Junita Diana

    2014-01-01

    During the fishing process, fish react to a trawl with a series of behaviours that often are species and size specific. Thus, a thorough understanding of fish behaviour in relation to fishing gear and a scientific understanding of the ability of different gear designs to utilize or stimulate various behavioural patterns during the catching process are essential for developing more efficient, selective, and environmentally friendly trawls. Although many behavioural studies using optical and acoustic observation systems have been conducted, harsh observation conditions on the fishing grounds often hamper the ability to directly observe fish behaviour in relation to fishing gear. As an alternative to optical and acoustic methods, we developed and applied a new mathematical model to catch data to extract detailed and quantitative information about species- and size-dependent escape behaviour in towed fishing gear such as trawls. We used catch comparison data collected with a twin trawl setup; the only difference between the two trawls was that a 12 m long upper section was replaced with 800 mm diamond meshes in one of them. We investigated the length-based escape behaviour of cod (Gadus morhua), haddock (Melanogrammus aeglefinus), saithe (Pollachius virens), witch flounder (Glyptocephalus cynoglossus), and lemon sole (Microstomus kitt) and quantified the extent to which behavioural responses set limits for the large mesh panel’s selective efficiency. Around 85% of saithe, 80% of haddock, 44% of witch flounder, 55% of lemon sole, and 55% of cod (below 68 cm) contacted the large mesh panel and escaped. We also demonstrated the need to account for potential selectivity in the trawl body, as it can bias the assessment of length-based escape behaviour. Our indirect assessment of fish behaviour was in agreement with the direct observations made for the same species in a similar section of the trawl body reported in the literature. PMID:24586403

  14. Coal liquefaction with subsequent bottoms pyrolysis

    DOEpatents

    Walchuk, George P.

    1978-01-01

    In a coal liquefaction process wherein heavy bottoms produced in a liquefaction zone are upgraded by coking or a similar pyrolysis step, pyrolysis liquids boiling in excess of about 1000.degree. F. are further reacted with molecular hydrogen in a reaction zone external of the liquefaction zone, the resulting effluent is fractionated to produce one or more distillate fractions and a bottoms fraction, a portion of this bottoms fraction is recycled to the reaction zone, and the remaining portion of the bottoms fraction is recycled to the pyrolysis step.

  15. Discarding of plaice (Pleuronectes platessa) in the Danish North Sea trawl fishery

    NASA Astrophysics Data System (ADS)

    Madsen, Niels; Feekings, Jordan; Lewy, Peter

    2013-01-01

    Plaice (Pleuronectes platessa) plays an important role in the North Sea benthic ecosystem and is by weight the most important commercial flatfish species in the North Sea demersal fishery. There is a high discarding of plaice in the active demersal fisheries in the North Sea. The change in fisheries management towards a more ecosystem based approach, together with a greater focus on sustainability, has caused a severe need for action. Subsequently, the European Commission is preparing regulations to reduce or even ban discards. The trawl fisheries are commercially the most important Danish fishery targeting plaice. Here we analyse discard data collected onboard Danish vessels in the period from 1998 to 2008. We describe the general patterns in these data by dividing them into three mesh size categories: 80-99 mm, 100-119 mm and ≥ 120 mm to reflect implemented technical measures of relevance. We analyse the landed and discarded portions in these mesh size categories and link the discarding to the minimum landing size. We employed a GAM model to assess how discarding of plaice below the minimum landing size is connected to relevant factors that could be of relevance from a management perspective. We identified a statistical significant effect of mesh size category and area. We discuss the results in relation to potential mitigation measures to be implemented in future fisheries management strategies.

  16. 78 FR 18879 - Fisheries Off West Coast States; Pacific Coast Groundfish Fishery; Trawl Rationalization Program...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-03-28

    ...This action revises several portions of the Pacific Coast Groundfish Fishery Trawl Rationalization Program (program) regulations in response to a court order requiring the National Marine Fisheries Service (NMFS) to reconsider the initial allocation of Pacific whiting (whiting) to the shorebased individual fishing quota (IFQ) fishery and the at-sea mothership fishery. Additionally, NMFS concludes after review of public comments and the record as a whole, that the Pacific Fishery Management Council's (Council's) recommendation to maintain the existing initial allocations of whiting is consistent with the Magnuson-Stevens Fishery Conservation and Management Act (MSA), the Pacific Coast Groundfish Fishery Management Plan (Groundfish FMP), and other applicable law. This final rule will affect the transfer of quota share (QS) and individual bycatch quota (IBQ) between QS accounts in the shorebased IFQ fishery, and severability of catch history assignments (CHAs) in the mothership fishery, both of which will be allowed on specified dates, with the exception of widow rockfish. Widow rockfish is no longer an overfished species and transfer of QS for this species will be reinstated pending reconsideration of the allocation of widow rockfish QS in a future action. The divestiture period for widow rockfish QS in the IFQ fishery will also be delayed indefinitely.

  17. 78 FR 72 - Fisheries Off West Coast States; Pacific Coast Groundfish Fishery Management Plan; Trawl...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-01-02

    ...This action proposes revisions to several portions of the Pacific Coast Groundfish Fishery Trawl Rationalization Program regulations and requests comments on NMFS' preliminary conclusion that the Pacific Fishery Management Council's (Council's) selection of the no action alternative regarding the reconsideration of initial allocation of Pacific whiting (whiting) is consistent with the Magnuson-Stevens Fishery Conservation and Management Act (MSA), the Pacific Coast Groundfish Fishery Management Plan (FMP), and other applicable law.. This action is necessary to comply with a court order requiring NMFS to reconsider the initial allocation of whiting to the shorebased individual fishing quota (IFQ) fishery and the at-sea mothership fishery. These proposed regulatory changes would affect the transfer of quota share (QS) and individual bycatch quota (IBQ) between QS accounts in the shorebased IFQ fishery, and severability of catch history assignments in the mothership fishery, both of which would be allowed on specified dates with the exception of widow rockfish. Widow rockfish is no longer an overfished species and transfer of QS for this species will be reinstated pending reconsideration of the allocation of widow rockfish QS in a future action. The divestiture period for widow rockfish QS in the IFQ fishery is also proposed to be delayed indefinitely.

  18. Bottom hole oil well pump

    SciTech Connect

    Hansen, J.E.; Hinds, W.E.; Oldershaw, P.V.

    1982-09-21

    A bottom hole well pump is disclosed comprising a pump housing supported by a control cable for raising and lowering the housing within tubing in a well, a linear motor within the housing causing reciprocation of a plunger extending into a pumping chamber formed by the housing with inlet and outlet check valves for controlling flow of oil or other liquid into the pumping chamber and from the pumping chamber into the tubing above the pump housing. In one embodiment, belleville-type springs are employed for storing energy as the plunger approaches its opposite limits of travel in order to initiate movement of the plunger in the opposite direction. In this embodiment, a single pumping chamber is formed above the linear motor with a single-valve block arranged above the pumping chamber and including inlet check valve means for controlling liquid flow into the pumping chamber and outlet check valve means for controlling liquid flow from the pumping chamber into the tubing interior above the pump housing. In another embodiment, pumping chambers are formed above and below the linear motor with a tubular plunger extending into both pumping chambers, in order to achieve pumping during both directions of travel of the plunger.

  19. Channelized bottom melting and stability of floating ice shelves

    NASA Astrophysics Data System (ADS)

    Rignot, E.; Steffen, K.

    2008-01-01

    The floating ice shelf in front of Petermann Glacier, in northwest Greenland, experiences massive bottom melting that removes 80% of its ice before calving into the Arctic Ocean. Detailed surveys of the ice shelf reveal the presence of 1-2 km wide, 200-400 m deep, sub-ice shelf channels, aligned with the flow direction and spaced by 5 km. We attribute their formation to the bottom melting of ice from warm ocean waters underneath. Drilling at the center of one of channel, only 8 m above sea level, confirms the presence of ice-shelf melt water in the channel. These deep incisions in ice-shelf thickness imply a vulnerability to mechanical break up and climate warming of ice shelves that has not been considered previously.

  20. Bottom water warming in the North Pacific Ocean.

    PubMed

    Fukasawa, Masao; Freeland, Howard; Perkin, Ron; Watanabe, Tomowo; Uchida, Hiroshi; Nishina, Ayako

    2004-02-26

    Observations of changes in the properties of ocean waters have been restricted to surface or intermediate-depth waters, because the detection of change in bottom water is extremely difficult owing to the small magnitude of the expected signals. Nevertheless, temporal changes in the properties of such deep waters across an ocean basin are of particular interest, as they can be used to constrain the transport of water at the bottom of the ocean and to detect changes in the global thermohaline circulation. Here we present a comparison of a trans-Pacific survey completed in 1985 (refs 4, 5) and its repetition in 1999 (ref. 6). We find that the deepest waters of the North Pacific Ocean have warmed significantly across the entire width of the ocean basin. Our observations imply that changes in water properties are now detectable in water masses that have long been insulated from heat exchange with the atmosphere.

  1. Characterization of a Louisiana Bay Bottom

    NASA Astrophysics Data System (ADS)

    Freeman, A. M.; Roberts, H. H.

    2016-02-01

    This study correlates side-scan sonar and CHIRP water bottom-subbottom acoustic amplitudes with cone penetrometer data to expand the limited understanding of the geotechnical properties of sediments in coastal Louisiana's bays. Standardized analysis procedures were developed to characterize the bay bottom and shallow subsurface of the Sister Lake bay bottom. The CHIRP subbottom acoustic data provide relative amplitude information regarding reflection horizons of the bay bottom and shallow subsurface. An amplitude analysis technique was designed to identify different reflectance regions within the lake from the CHIRP subbottom profile data. This amplitude reflectivity analysis technique provides insight into the relative hardness of the bay bottom and shallow subsurface, useful in identifying areas of erosion versus deposition from storms, as well as areas suitable for cultch plants for state oyster seed grounds, or perhaps other restoration projects. Side-scan and CHIRP amplitude reflectivity results are compared to penetrometer data that quantifies geotechnical properties of surface and near-surface sediments. Initial results indicate distinct penetrometer signatures that characterize different substrate areas including soft bottom, storm-deposited silt-rich sediments, oyster cultch, and natural oyster reef areas. Although amplitude analysis of high resolution acoustic data does not directly quantify the geotechnical properties of bottom sediments, our analysis indicates a close relationship. The analysis procedures developed in this study can be applied in other dynamic coastal environments, "calibrating" the use of synoptic acoustic methods for large-scale water bottom characterization.

  2. A ocean bottom vector magnetometer

    NASA Astrophysics Data System (ADS)

    Wang, Xiaomei; Teng, Yuntian; Wang, Chen; Ma, Jiemei

    2017-04-01

    The new development instrument with a compact spherical coil system and Overhauser magnetometer for measuring the total strength of the magnetic field and the vectors of strength, Delta inclination - Delta declination, meanwhile we also use a triaxial fluxgate instrument of the traditional instrument for geomagnetic vector filed measurement. The advantages of this method are be calibrated by each other and get good performances with automatic operation, good stability and high resolution. Firstly, a brief description of the instrument measurement principles and the key technologies are given. The instrument used a spherical coil system with 34 coils to product the homogeneous volume inside the coils which is large enough to accommodate the sensor of Overhauser total field sensor; the rest of the footlocker-sized ocean-bottom vector magnetometer consists of equipment to run the sensors and records its data (batteries and a data logger), weight to sink it to the sea floor, a remote-controlled acoustic release and flotation to bring the instrument back to the surface. Finally, the accuracy of the instrument was tested in the Geomagnetic station, and the measurement accuracies of total strength and components were better than 0.2nT and 1nT respectively. The figure 1 shows the development instrument structure. it includes six thick glass spheres which protect the sensor, data logger and batteries from the pressures of the deep sea, meanwhile they also provide recycling positive buoyancy; To cushion the glass, the spheres then go inside yellow plastic "hardhats". The triaxial fluxgate is inside No.1 glass spheres, data logger and batteries are inside No.2 glass spheres, the new vector sensor is inside No.3 glass spheres, acoustic communication unit is inside No.4 glass spheres, No.5 and No.6 glass spheres are empty which only provide recycling positive buoyancy. The figure 2 shows the development instrument Physical photo.

  3. Underwater MASW to evaluate stiffness of water-bottom sediments

    USGS Publications Warehouse

    Park, C.B.; Miller, R.D.; Xia, J.; Ivanov, J.; Sonnichsen, G.V.; Hunter, J.A.; Good, R.L.; Burns, R.A.; Christian, H.

    2005-01-01

    The multichannel analysis of surface waves (MASW) is initially intended as a land survey method to investigate the near-surface materials for their elastic properties. The acquired data are first analyzed for dispersion characteristics and, from these the shear-wave velocity is estimated using an inversion technique. Land applications show the potential of the MASW method to map 2D bedrock surface, zones of low strength, Poisson's ratio, voids, as well as to generate shear-wave profiles for various othe geotechnical problems. An overview is given of several underwater applications of the MASW method to characterize stiffness distribution of water-bottom sediments. The first application details the survey under shallow-water (1-6 m) in the Fraser River (Canada). The second application is an innovative experimental marine seismic survey in the North Atlantic Ocean near oil fields in Grand Bank offshore Newfoundland.

  4. Impacts of Bottom Fishing on Sediment Biogeochemical and Biological Parameters in Cohesive and Non-cohesive Sediments

    NASA Astrophysics Data System (ADS)

    Sciberras, M.; Hiddink, J. G.; Powell, C.; Parker, R.; Krӧger, S.; Bolam, S. G.; Robertson, C.

    2016-02-01

    Sediment resuspension and bed reworking by tides, waves and biological activity are frequent in the energetic coastal environments. Sediment mixing by tides and waves are generally more important in regulating sediment processes in advection-dominated system such as sandy sediments, whereas sediment reworking by bioturbation is more important in diffusion-dominated systems such as muddy sediments. Bottom fishing constitutes an additional significant impact on benthic communities and sediment biogeochemical processes in coastal areas through physical changes in sediment resuspension and mixing and changes to bioturbating fauna. This study examined the biological (macro-infaunal) and biogeochemical responses to fishing at a muddy and sandy site in the Irish Sea that were predominantly impacted by otter trawls and scallop dredges, respectively. The sandy habitat (>90% sand) was typical of a hydrodynamic environment characterized by a diverse array of small infaunal species, low organic carbon levels and fast remineralisation of organic matter in the sediment. The muddier habitat (>65% fines) was dominated by fewer but larger bioturbating species compared to sand, and illustrated highly diffusional solute transport, higher organic carbon content and a shallower oxygen penetration depth. Generally there appeared to be no clear statistically significant changes in the biogeochemistry of the sandy or muddy habitat that could be attributed to different intensities of fishing. However, pore-water nutrient profiles of ammonium, phosphate and silicate provided clear evidence of organic matter burial and/or mixing as a result of trawling at the muddy site. The biogeochemistry at the sandy site appeared to remain dominated by the natural physical environment, so impact of fishing disturbance was less evident. These results suggest that fishing does not have comparable effects on the biology and biogeochemical processes in all benthic habitats.

  5. Impact of discards of beam trawl fishing on the nematode community from the Tagus estuary (Portugal).

    PubMed

    Franco, M A; Steyaert, M; Cabral, H N; Tenreiro, R; Chambel, L; Vincx, M; Costa, M J; Vanaverbeke, J

    2008-10-01

    The impact of dead discards, originating from beam trawl fishing on the nematode community from the Tagus estuary was investigated in terms of vertical distribution of the dominant nematode groups. Sediment cores were collected from a mud-flat from the Tagus estuary. Crangoncrangon (Linnaeus, 1758) carcasses were added to the surface of the cores, simulating the settling of dead discards on the sediment. The vertical distribution of the dominant nematode groups was determined up to 4cm deep at four different moments in time post deposition (0, 2, 4 and 6h) and compared to control cores. The C.crangon addition to the sediment led to the formation of black spots and therefore oxygen depleted areas at the sediment surface. The Chromadora/Ptycholaimellus group, normally dominant at the surface layer, migrated downwards due to their high sensibility to toxic conditions. Sabatieria presented the opposite trend and became the dominant group at the surface layer. Since Sabatieria is tolerant to oxygen stressed conditions and high sulphide concentrations, we suggest that it migrated opportunistically towards an unoccupied niche. Daptonema, Metachromadora and Terschellingia did not show any vertical migration, reflecting their tolerance to anoxic and high sulphidic conditions. Our study showed that an accumulation of dead discards at the sediment surface might therefore alter the nematode community vertical distribution. This effect is apparently closely related to toxic conditions in the sediment, induced by the deposition of C.crangon at the sediment surface. These alterations might be temporal and reflect an adaptation of the nematode community to dynamic intertidal environments.

  6. Can pelagic forage fish and spawning cisco (Coregonus artedi) biomass in the western arm of Lake Superior be assessed with a single summer survey?

    USGS Publications Warehouse

    Yule, D.L.; Stockwell, J.D.; Schreiner, D.R.; Evrard, L.M.; Balge, M.; Hrabik, T.R.

    2009-01-01

    Management efforts to rehabilitate lake trout Salvelinus namaycush in Lake Superior have been successful and the recent increase in their numbers has led to interest in measuring biomass of pelagic prey fish species important to these predators. Lake Superior cisco Coregonus artedi currently support roe fisheries and determining the sustainability of these fisheries is an important management issue. We conducted acoustic and midwater trawl surveys of the western arm of Lake Superior during three periods: summer (July-August), October, and November 2006 to determine if a single survey can be timed to estimate biomass of both prey fish and spawning cisco. We evaluated our methods by comparing observed trawl catches of small (<250 mm total length) and large fish to expected trawl catches based on acoustic densities in the trawl path. We found the relationship between observed and expected catches approached unity over a wide range of densities, suggesting that our acoustic method provided reasonable estimates of fish density, and that midwater trawling methods were free of species- and size-selectivity issues. Rainbow smelt Osmerus mordax was by number the most common species captured in the nearshore (<80 m bathymetric depth) stratum during all three surveys, while kiyi Coregonus kiyi was predominant offshore except during November. Total biomass estimates of rainbow smelt in the western arm were similar during all three surveys, while total biomass of kiyi was similar between summer and October, but was lower in November. Total biomass of large cisco increased substantially in November, while small bloater Coregonus hoyi biomass was lower. We compared our summer 2006 estimates of total fish biomass to the results of a summer survey in 1997 and obtained similar results. We conclude that the temporal window for obtaining biomass estimates of pelagic prey species in the western arm of Lake Superior is wide (July through October), but estimating spawning cisco abundance

  7. Bottom-up multiferroic nanostructures

    NASA Astrophysics Data System (ADS)

    Ren, Shenqiang

    Multiferroic and especially magnetoelectric (ME) nanocomposites have received extensive attention due to their potential applications in spintronics, information storage and logic devices. The extrinsic ME coupling in composites is strain mediated via the interface between the piezoelectric and magnetostrictive components. However, the design and synthesis of controlled nanostructures with engineering enhanced coupling remain a significant challenge. The purpose of this thesis is to create nanostructures with very large interface densities and unique connectivities of the two phases in a controlled manner. Using inorganic solid state phase transformations and organic block copolymer self assembly methodologies, we present novel self assembly "bottom-up" techniques as a general protocol for the nanofabrication of multifunctional devices. First, Lead-Zirconium-Titanate/Nickel-Ferrite (PZT/NFO) vertical multilamellar nanostructures have been produced by crystallizing and decomposing a gel in a magnetic field below the Curie temperature of NFO. The ensuing microstructure is nanoscopically periodic and anisotropic. The wavelength of the PZT/NFO alternation, 25 nm, agrees within a factor of two with the theoretically estimated value. The macroscopic ferromagnetic and magnetoelectric responses correspond qualitatively and semi-quantitatively to the features of the nanostructure. The maximum of the field dependent magnetoelectric susceptibility equals 1.8 V/cm Oe. Second, a magnetoelectric composite with controlled nanostructures is synthesized using co-assembly of two inorganic precursors with a block copolymer. This solution processed material consists of hexagonally arranged ferromagnetic cobalt ferrite (CFO) nano-cylinders within a matrix of ferroelectric Lead-Zirconium-Titanate (PZT). The initial magnetic permeability of the self-assembled CFO/PZT nanocomposite changes by a factor of 5 through the application of 2.5 V. This work may have significant impact on the

  8. Tsunami Energy, Ocean-Bottom Pressure, and Hydrodynamic Force from Stochastic Bottom Displacement

    NASA Astrophysics Data System (ADS)

    Ramadan, Khaled T.; Omar, M. A.; Allam, Allam A.

    2017-03-01

    Tsunami generation and propagation due to a randomly fluctuating of submarine earthquake modeled by vertical time-dependent of a stochastic bottom displacement are investigated. The increase in oscillations and amplitude in the free surface elevation are controlled by the noise intensity parameter of the stochastic bottom displacement. Evolution of kinetic and potential energy of the resulting waves by the stochastic bottom displacement is examined. Exchange between potential and kinetic energy was achieved in the propagation process. The dynamic ocean-bottom pressure during tsunami generation is investigated. As the vertical displacement of the stochastic bottom increases, the peak amplitude of the ocean-bottom pressure increases through the dynamic effect. Time series of the maximum tsunami wave amplitude, kinetic and potential energy, wave and ocean-bottom pressure gauges and the hydrodynamic force caused by the stochastic source model under the effect of the water depth of the ocean are investigated.

  9. 50 kHz bottom backscattering measurements from two types of artificially roughened sandy bottoms

    NASA Astrophysics Data System (ADS)

    Son, Su-Uk; Cho, Sungho; Choi, Jee Woong

    2016-07-01

    Laboratory measurements of 50 kHz bottom backscattering strengths as a function of grazing angle were performed on the sandy bottom of a water tank; two types of bottom roughnesses, a relatively smooth interface and a rough interface, were created on the bottom surface. The roughness profiles of the two interface types were measured directly using an ultrasound arrival time difference of 5 MHz and then were Fourier transformed to obtain the roughness power spectra. The measured backscattering strengths increased from -29 to 0 dB with increasing grazing angle from 35 to 86°, which were compared to theoretical backscattering model predictions. The comparison results implied that bottom roughness is a key factor in accurately predicting bottom scattering for a sandy bottom.

  10. 50 CFR 660.381 - Limited entry trawl fishery management measures.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... specific latitude and longitude coordinates at §§ 660.398 through 660.399: Thompson Seamount, President Jackson Seamount, Cordell Bank (50 fm (91 m) isobath), Harris Point, Richardson Rock, Scorpion, Painted..., and Santa Barbara. Fishing with bottom contact gear is also prohibited within the Davidson...

  11. Infaunal community responses to a gradient of trawling disturbance and a long-term Fishery Exclusion Zone in the Southern Tyrrhenian Sea

    NASA Astrophysics Data System (ADS)

    Mangano, M. Cristina; Kaiser, Michel J.; Porporato, Erika M. D.; Lambert, Gwladys I.; Rinelli, Paola; Spanò, Nunziacarla

    2014-03-01

    Historically the majority of Mediterranean trawl fisheries occur on the continental shelf with a smaller proportion focused on the shelf slope and deep sea areas. Understanding how trawl fisheries affect the wider ecosystem is an important component of the ecosystem-based approach to fisheries management. In this context the current study examined the impact of the otter trawl fishery on the infaunal communities found on the continental shelf and upper slope off the coast of Sicily and Calabria, Italy. A total of thirty six sites were sampled across a gradient of fishing intensity and from within a large bay from which trawling has been excluded for 22 years. Fishing intensities were ascertained post-hoc from vessel monitoring system data. Seabed characteristics of the sites studied were uniform across the continental shelf and slope areas that were studied, such that the only factor that varied was fishing intensity. The density index (DI) and total number of species (S) were significantly higher in the fishery closure area compared with other continental shelf sites. In particular, bioturbating decapod fauna occurred only within the fishery closure area. Fished sites were dominated primarily by burrowing deposit feeding worms, small bivalves and scavenging biota. In contrast, the response to fishing on the upper slope was less clear. This observation was treated with caution as the power to detect fishing effects was lower for the upper slope sites as a result of possible illegal fishing that had compromised two of the four replicate sites within the closed area. While the present study was able to quantify the effect of the demersal trawl fleet on the benthic infauna of the continental shelf, the effects of trawling on the upper shelf slope remain unclear and warrant further study.

  12. Pipeline bottoming cycle study. Final report

    SciTech Connect

    Not Available

    1980-06-01

    The technical and economic feasibility of applying bottoming cycles to the prime movers that drive the compressors of natural gas pipelines was studied. These bottoming cycles convert some of the waste heat from the exhaust gas of the prime movers into shaft power and conserve gas. Three typical compressor station sites were selected, each on a different pipeline. Although the prime movers were different, they were similar enough in exhaust gas flow rate and temperature that a single bottoming cycle system could be designed, with some modifications, for all three sites. Preliminary design included selection of the bottoming cycle working fluid, optimization of the cycle, and design of the components, such as turbine, vapor generator and condensers. Installation drawings were made and hardware and installation costs were estimated. The results of the economic assessment of retrofitting bottoming cycle systems on the three selected sites indicated that profitability was strongly dependent upon the site-specific installation costs, how the energy was used and the yearly utilization of the apparatus. The study indicated that the bottoming cycles are a competitive investment alternative for certain applications for the pipeline industry. Bottoming cycles are technically feasible. It was concluded that proper design and operating practices would reduce the environmental and safety hazards to acceptable levels. The amount of gas that could be saved through the year 2000 by the adoption of bottoming cycles for two different supply projections was estimated as from 0.296 trillion ft/sup 3/ for a low supply projection to 0.734 trillion ft/sup 3/ for a high supply projection. The potential market for bottoming cycle equipment for the two supply projections varied from 170 to 500 units of varying size. Finally, a demonstration program plan was developed.

  13. Analyses of trawling track and fishing activity based on the data of vessel monitoring system (VMS): A case study of the single otter trawl vessels in the Zhoushan fishing ground

    NASA Astrophysics Data System (ADS)

    Wang, Yang; Wang, Yingbin; Zheng, Ji

    2015-02-01

    The original purpose of Vessel Monitoring System (VMS) is for enforcement and control of vessel sailing. With the application of VMS in fishing vessels, more and more population dynamic studies have used VMS data to improve the accuracy of fisheries stock assessment. In this paper, we simulated the trawl trajectory under different time intervals using the cubic Hermite spline (cHs) interpolation method based on the VMS data of 8 single otter trawl vessels (totally 36000 data items) fishing in Zhoushan fishing ground from September 2012 to December 2012, and selected the appropriate time interval. We then determined vessels' activities (fishing or non-fishing) by comparing VMS speed data with the corresponding speeds from logbooks. The results showed that the error of simulated trajectory greatly increased with the increase of time intervals of VMS data when they were longer than 30 minutes. Comparing the speeds from VMS with those from the corresponding logbooks, we found that the vessels' speeds were between 2.5 kn and 5.0 kn in fishing. The cHs interpolation method is a new choice for improving the accuracy of estimation of sailing trajectory, and the VMS can be used to determine the vessels' activities with the analysis of their trajectories and speeds. Therefore, when the fishery information is limited, VMS can be one of the important data sources for fisheries stock assessment, and more attention should be paid to its construction and application to fisheries stock assessment and management.

  14. Bottom stress measurements on the inner shelf

    USGS Publications Warehouse

    Sherwood, Christopher R.; Scully, Malcolm; Trowbridge, John

    2015-01-01

    Bottom stress shapes the mean circulation patterns, controls sediment transport, and influences benthic habitat in the coastal ocean. Accurate and precise measurements of bottom stress have proved elusive, in part because of the difficulty in separating the turbulent eddies that transport momentum from inviscid wave-induced motions. Direct covariance measurements from a pair of acoustic Doppler velocimeters has proved capable of providing robust estimates, so we designed a mobile platform coined the NIMBBLE for these measurements, and deployed two of them and two more conventional quadpods at seven sites on the inner shelf over a period of seven months. The resulting covariance estimates of stress and bottom roughness were lower than log-fit estimates, especially during calmer periods. Analyses of these data suggest the NIMBBLEs may provide an accurate and practical method for measuring bottom stress.

  15. Benchmark cross sections for bottom quark production

    SciTech Connect

    Berger, E.L.

    1988-01-07

    A summary is presented of theoretical expectations for the total cross sections for bottom quark production, for longitudinal and transverse momentum distributions, and for b, /bar b/ momentum correlations at Fermilab fixed target and collider energies.

  16. Developing the new method measuring thickness and quality of bottom sediments in using ultrasonic wave

    NASA Astrophysics Data System (ADS)

    Ishikawa, Tomonari; Matsumoto, Yoshitaka; Hozumi, Naohiro

    2017-07-01

    Measuring the quality and thickness of bottom sediment that it causes some environmental problem, the shortage of water storage volume and anaerobic zone in the bottom of reservoirs, takes huge costs and long time. The purpose of our research is to develop a new method to measure the thickness and size characteristics of bottom sediment using ultrasonic waves that allow obtaining the quality of it indirectly. This new method applies the echo characteristic of bottom sediment in each particle size using the higher frequency than another method, which uses for measuring geological layer at seabed survey. In this research, we attempted to estimate the particle size of bottom sediment by ultrasonic waves irradiating from two different directions such as horizontal and vertical direction, and compare these experiments. We use sediment that we sampled from the lake bottom classified by particle size. At first, we acquired the results that show a relation between particle size and intensity; the obtained echo intensities, which were observed with oscilloscope, were changed depending on the particle sizes. In addition, peaks, which were obtained by power spectrum analysis, appeared on the same frequency band even though the different particle size. However the relation between the experiments of horizontal and vertical direction is not clear. This research indicated the possibility of estimating the characteristics of each particle size in bottom sediment by ultrasonic waves.

  17. Bottom production asymmetries at the LHC

    SciTech Connect

    Norrbin, E.; Vogt, R.

    1999-01-01

    We present results on bottom hadron production asymmetries at the LHC within both the Lund string fragmentation model and the intrinsic bottom model. The main aspects of the models are summarized and specific predictions for pp collisions at 14 TeV are given. Asymmetries are found to be very small at central rapidities increasing to a few percent at forward rapidities. At very large rapidities intrinsic production could dominate but this region is probably out of reach of any experiment.

  18. Numerical tsunami modeling and the bottom relief

    NASA Astrophysics Data System (ADS)

    Kulikov, E. A.; Gusiakov, V. K.; Ivanova, A. A.; Baranov, B. V.

    2016-11-01

    The effect of the quality of bathymetric data on the accuracy of tsunami-wave field calculation is considered. A review of the history of the numerical tsunami modeling development is presented. Particular emphasis is made on the World Ocean bottom models. It is shown that the modern digital bathymetry maps, for example, GEBCO, do not adequately simulate the sea bottom in numerical models of wave propagation, leading to considerable errors in estimating the maximum tsunami run-ups on the coast.

  19. The GITEWS ocean bottom sensor packages

    NASA Astrophysics Data System (ADS)

    Boebel, O.; Busack, M.; Flueh, E. R.; Gouretski, V.; Rohr, H.; Macrander, A.; Krabbenhoeft, A.; Motz, M.; Radtke, T.

    2010-08-01

    The German-Indonesian Tsunami Early Warning System (GITEWS) aims at reducing the risks posed by events such as the 26 December 2004 Indian Ocean tsunami. To minimize the lead time for tsunami alerts, to avoid false alarms, and to accurately predict tsunami wave heights, real-time observations of ocean bottom pressure from the deep ocean are required. As part of the GITEWS infrastructure, the parallel development of two ocean bottom sensor packages, PACT (Pressure based Acoustically Coupled Tsunameter) and OBU (Ocean Bottom Unit), was initiated. The sensor package requirements included bidirectional acoustic links between the bottom sensor packages and the hosting surface buoys, which are moored nearby. Furthermore, compatibility between these sensor systems and the overall GITEWS data-flow structure and command hierarchy was mandatory. While PACT aims at providing highly reliable, long term bottom pressure data only, OBU is based on ocean bottom seismometers to concurrently record sea-floor motion, necessitating highest data rates. This paper presents the technical design of PACT, OBU and the HydroAcoustic Modem (HAM.node) which is used by both systems, along with first results from instrument deployments off Indonesia.

  20. Proposal for a Bottom Collider Detector

    SciTech Connect

    Van Berg, R.; Hughes, R.; Lockyer, N. S.; Karchin, P.

    1987-03-01

    The ultimate goal of this experiment is to record about 100 million bottom events tagged with a lepton trigger. It is only with a sample of this size that CP violation and very rare decays from bottom can be studied. In order to produce 109 bottom events an integrated luminosity of 500 pb-1 is needed, which could be accomplished in a one year run of 107 sec at a luminosity of 5 x 1031 cm-2sec-1, assuming a total bottom cross section of 10 μbarns. With a trigger efficiency of about 10 percent, the goal of about 108 bottom events recorded seems attainable. Having produced and recorded this large data set, the task of reconstructing these events and extracting physics will be a tremendous challenge to the detector design and physicists involved. This experiment begins the process of how t,o best tag a very large sample of bottom events in a high energy hadron collider environment. The most challenging aspects concern studying the secondary vertices when multiple scattering effects are large and detecting very soft leptons in a busy tracking environment. This will lead to a better exploitation of the high luminosity Tevatron as well as eventually preparing for the SSC.

  1. Detection probabilities of electrofishing, hoop nets, and benthic trawls for fishes in two western North American rivers

    USGS Publications Warehouse

    Smith, Christopher D.; Quist, Michael C.; Hardy, Ryan S.

    2015-01-01

    Research comparing different sampling techniques helps improve the efficiency and efficacy of sampling efforts. We compared the effectiveness of three sampling techniques (small-mesh hoop nets, benthic trawls, boat-mounted electrofishing) for 30 species in the Green (WY, USA) and Kootenai (ID, USA) rivers by estimating conditional detection probabilities (probability of detecting a species given its presence at a site). Electrofishing had the highest detection probabilities (generally greater than 0.60) for most species (88%), but hoop nets also had high detectability for several taxa (e.g., adult burbot Lota lota, juvenile northern pikeminnow Ptychocheilus oregonensis). Benthic trawls had low detection probabilities (<0.05) for most taxa (84%). Gear-specific effects were present for most species indicating large differences in gear effectiveness among techniques. In addition to gear effects, habitat characteristics also influenced detectability of fishes. Most species-specific habitat relationships were idiosyncratic and reflected the ecology of the species. Overall findings of our study indicate that boat-mounted electrofishing and hoop nets are the most effective techniques for sampling fish assemblages in large, coldwater rivers.

  2. Chemical data for bottom sediment, lake water, bottom-sediment pore water, and fish in Mountain Creek Lake, Dallas, Texas, 1994-96

    USGS Publications Warehouse

    Jones, S.A.; Van Metre, P.C.; Moring, J.B.; Braun, C.L.; Wilson, J.T.; Mahler, B.J.

    1997-01-01

    Mountain Creek Lake is a reservoir adjacent to two U.S. Department of the Navy facilities, the Naval Weapons Industrial Reserve Plant and the Naval Air Station in Dallas, Texas. A Resource Conservation and Recovery Act Facility Investigation found ground-water plumes containing chlorinated solvents on both facilities. These findings led to a U.S. Geological Survey study of Mountain Creek Lake adjacent to both facilities between June 1994 and August 1996. Bottom sediments, lake water, bottom-sediment pore water, and fish were collected for chemical analysis.

  3. Pair-Trawl Detection of PIT-Tagged Juvenile Salmonids Migrating in the Columbia River Estuary, 2008 Report of Research.

    SciTech Connect

    Magie, Robert J.; Morris, Matthew S.; Ledgerwood, Richard D.

    2009-06-03

    In 2008, we sampled migrating juvenile Pacific salmonids Oncorhynchus spp. tagged with passive integrated transponder (PIT) tags using a surface pair trawl in the upper Columbia River estuary (rkm 61-83). The cod-end of the trawl was replaced with a cylindrical PIT-tag detection antenna with an 86-cm-diameter fish-passage opening and two detection coils connected in series. The pair trawl was 105 m long with a 91.5-m opening between the wings and a sample depth of 4.9 m. Also during 2008, we finalized the development of a prototype 'matrix' antenna, which was larger than previous antennas by a considerable magnitude. The matrix antenna consisted of 6 coils: a 3-coil front component and a 3-coil rear component, which were separated by 1.5-m of net mesh. The fish-passage opening was 2.5 m wide by 3.0 m tall and was attached to a standard-size pair trawl net. Intermittent sampling with a single crew began on 7 March and targeted yearling Chinook salmon O. tshawytscha and steelhead O. mykiss. Daily sampling using two crews began on 30 April and continued through 14 June; during this period we detected 2.7% of all juvenile salmonids previously detected at Bonneville Dam--a measure of sample efficiency. Sampling with a single crew continued through 20 August and targeted subyearling Chinook salmon. We detected 7,397 yearling Chinook salmon, 2,735 subyearling Chinook salmon, 291 coho salmon O. kisutch, 5,950 steelhead, and 122 sockeye salmon O. nerka in the upper estuary. We deployed the matrix antenna system and the older, cylindrical antenna system (86-cm-diameter fish-passage opening) simultaneously in mid-May 2008 to test matrix detection efficiency. The cylindrical antenna system had been used successfully in 2007 and early 2008. Because distribution of migrating salmonids in the estuary changes rapidly, we felt that a tandem sampling effort between the two systems was the only way to truly evaluate comparative detection efficiency. We deployed both systems within 1

  4. A visual survey technique for deep-water fishes: estimating anglerfish Lophius spp. abundance in closed areas.

    PubMed

    McIntyre, F D; Collie, N; Stewart, M; Scala, L; Fernandes, P G

    2013-10-01

    A visual survey technique was employed to estimate the abundance and distribution of anglerfish Lophius spp. in areas where destructive sampling methods, such as trawling, are unacceptable. To enable visual surveying at depths of over 300 m, a deep towed vehicle was developed equipped with video, lights and other sensors and was towed at speeds of up to 1·5 m s⁻¹ and altitudes of up to 10 m (from the seabed) to survey large areas of the seabed around the Rockall Bank in the north-west Atlantic Ocean. The system allowed for areas up to 125 000 m² to be surveyed, a substantial area comparable to that surveyed by demersal-trawl sampling. Lophius spp. densities ranged from 15 to 736 fish km⁻²; these are comparable to estimated Lophius spp. densities determined by trawl surveys in adjacent areas. Estimates of Lophius spp. abundance in the closed areas ranged between 99,855 and 176,887 for the time series considered (2007-2011). © 2013 The Authors. Journal of Fish Biology © 2013 The Fisheries Society of the British Isles.

  5. A Dataset of Deep-Sea Fishes Surveyed by Research Vessels in the Waters around Taiwan

    PubMed Central

    Shao, Kwang-Tsao; Lin, Jack; Yeh, Hsin-Ming; Lee, Mao-Yin; Chen, Lee-Sea; Lin, Hen-Wei

    2014-01-01

    Abstract The study of deep-sea fish fauna is hampered by a lack of data due to the difficulty and high cost incurred in its surveys and collections. Taiwan is situated along the edge of the Eurasia fig, at the junction of three Large Marine Ecosystems or Ecoregions of the East China Sea, South China Sea and the Philippines. As nearly two-thirds of its surrounding marine ecosystems are deep-sea environments, Taiwan is expected to hold a rich diversity of deep-sea fish. However, in the past, no research vessels were employed to collect fish data on site. Only specimens, caught by bottom trawl fishing in the waters hundreds of meters deep and missing precise locality information, were collected from Dasi and Donggang fishing harbors. Began in 2001, with the support of National Science Council, research vessels were made available to take on the task of systematically collecting deep-sea fish specimens and occurrence records in the waters surrounding Taiwan. By the end of 2006, a total of 3,653 specimens, belonging to 26 orders, 88 families, 198 genera and 366 species, were collected in addition to data such as sampling site geographical coordinates and water depth, and fish body length and weight. The information, all accessible from the “Database of Taiwan’s Deep-Sea Fauna and Its Distribution (http://deepsea.biodiv.tw/)” as part of the “Fish Database of Taiwan,” can benefit the study of temporal and spatial changes in distribution and abundance of fish fauna in the context of global deep-sea biodiversity. PMID:25610339

  6. A Dataset of Deep-Sea Fishes Surveyed by Research Vessels in the Waters around Taiwan.

    PubMed

    Shao, Kwang-Tsao; Lin, Jack; Yeh, Hsin-Ming; Lee, Mao-Yin; Chen, Lee-Sea; Lin, Hen-Wei

    2014-01-01

    The study of deep-sea fish fauna is hampered by a lack of data due to the difficulty and high cost incurred in its surveys and collections. Taiwan is situated along the edge of the Eurasia fig, at the junction of three Large Marine Ecosystems or Ecoregions of the East China Sea, South China Sea and the Philippines. As nearly two-thirds of its surrounding marine ecosystems are deep-sea environments, Taiwan is expected to hold a rich diversity of deep-sea fish. However, in the past, no research vessels were employed to collect fish data on site. Only specimens, caught by bottom trawl fishing in the waters hundreds of meters deep and missing precise locality information, were collected from Dasi and Donggang fishing harbors. Began in 2001, with the support of National Science Council, research vessels were made available to take on the task of systematically collecting deep-sea fish specimens and occurrence records in the waters surrounding Taiwan. By the end of 2006, a total of 3,653 specimens, belonging to 26 orders, 88 families, 198 genera and 366 species, were collected in addition to data such as sampling site geographical coordinates and water depth, and fish body length and weight. The information, all accessible from the "Database of Taiwan's Deep-Sea Fauna and Its Distribution (http://deepsea.biodiv.tw/)" as part of the "Fish Database of Taiwan," can benefit the study of temporal and spatial changes in distribution and abundance of fish fauna in the context of global deep-sea biodiversity.

  7. 50 CFR Table 35 to Part 679 - Apportionment of Crab PSC and Halibut PSC Between the Amendment 80 and BSAI Trawl Limited Access...

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 50 Wildlife and Fisheries 13 2013-10-01 2013-10-01 false Apportionment of Crab PSC and Halibut PSC... 35 to Part 679—Apportionment of Crab PSC and Halibut PSC Between the Amendment 80 and BSAI Trawl Limited Access Sectors Fishery Year Halibut PSC limit in the BSAI Zone 1 Red king crab PSC limit . . . C...

  8. 50 CFR Table 35 to Part 679 - Apportionment of Crab PSC and Halibut PSC Between the Amendment 80 and BSAI Trawl Limited Access...

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 50 Wildlife and Fisheries 13 2014-10-01 2014-10-01 false Apportionment of Crab PSC and Halibut PSC... 35 to Part 679—Apportionment of Crab PSC and Halibut PSC Between the Amendment 80 and BSAI Trawl Limited Access Sectors Fishery Year Halibut PSC limit in the BSAI Zone 1 Red king crab PSC limit . . . C...

  9. 50 CFR Table 35 to Part 679 - Apportionment of Crab PSC and Halibut PSC Between the Amendment 80 and BSAI Trawl Limited Access...

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 50 Wildlife and Fisheries 9 2010-10-01 2010-10-01 false Apportionment of Crab PSC and Halibut PSC... 35 to Part 679—Apportionment of Crab PSC and Halibut PSC Between the Amendment 80 and BSAI Trawl Limited Access Sectors Fishery Year Halibut PSC limit in the BSAI Zone 1 Red king crab PSC limit . . . C...

  10. 50 CFR Table 35 to Part 679 - Apportionment of Crab PSC and Halibut PSC Between the Amendment 80 and BSAI Trawl Limited Access...

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 50 Wildlife and Fisheries 11 2011-10-01 2011-10-01 false Apportionment of Crab PSC and Halibut PSC... 35 to Part 679—Apportionment of Crab PSC and Halibut PSC Between the Amendment 80 and BSAI Trawl Limited Access Sectors Fishery Year Halibut PSC limit in the BSAI Zone 1 Red king crab PSC limit . . . C...

  11. 50 CFR Table 35 to Part 679 - Apportionment of Crab PSC and Halibut PSC Between the Amendment 80 and BSAI Trawl Limited Access...

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 50 Wildlife and Fisheries 13 2012-10-01 2012-10-01 false Apportionment of Crab PSC and Halibut PSC... 35 to Part 679—Apportionment of Crab PSC and Halibut PSC Between the Amendment 80 and BSAI Trawl Limited Access Sectors Fishery Year Halibut PSC limit in the BSAI Zone 1 Red king crab PSC limit . . . C...

  12. 50 CFR Table 33 to Part 679 - Annual Apportion of Amendment 80 Species ITAC Between the Amendment 80 and BSAI Trawl Limited...

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 50 Wildlife and Fisheries 9 2010-10-01 2010-10-01 false Annual Apportion of Amendment 80 Species ITAC Between the Amendment 80 and BSAI Trawl Limited Access Sectors (Except Yellowfin Sole) 33 Table 33... ALASKA Pt. 679, Table 33 Table 33 to Part 679— Annual Apportion of Amendment 80 Species ITAC Between...

  13. Bottom shear stress in unsteady sewer flow.

    PubMed

    Bares, V; Jirák, J; Pollert, J

    2006-01-01

    The properties of unsteady open-channel turbulent flow were theoretically and experimentally investigated in a circular cross section channel with fixed sediment deposits. Velocity and turbulence distribution data were obtained using an ultrasonic velocity profiler (UVP). Different uniform flow conditions and triangular-shaped hydrographs were analysed. The hydrograph analysis revealed a dynamic wave behaviour, where the time lags of mean cross section velocity, friction velocity, discharge and flow depth were all evident. The bottom shear stress dynamic behaviour was estimated using four different approaches. Measurements of the velocity distribution in the inner region of the turbulent layer and of the Reynolds stress distribution in the turbulent flow provided the analysed data sets of the bottom shear stress. Furthermore, based on the Saint Venant equation, the bottom shear stress time behaviour was studied using both the kinematic and the dynamic flow principles. The dynamic values of the bottom shear stress were compared with those for the steady flow conditions. It is evident that bottom shear stress varies along the generated flood hydrograph and its variation is the function of the flow unsteadiness. Moreover, the kinematic flow principle is not an adequate type of approximation for presented flow conditions.

  14. Development of a new multiple sampling trawl with autonomous opening/closing net control system for sampling juvenile pelagic fish

    NASA Astrophysics Data System (ADS)

    Oozeki, Yoshioki; Hu, Fuxiang; Tomatsu, Chiaki; Kubota, Hiroshi

    2012-03-01

    A new multiple layer sampling trawl with an autonomous net opening/closing control system was developed to sample pelagic juvenile fish quantitatively. The new trawl system, based on the Matsuda-Oozeki-Hu Trawl (MOHT), has a rigid-frame 3.3 m high and 2.35 m wide and five nets of 11.0 m length with a rectangular mouth of 2.22 m×1.81 m (4 m2 mouth area; large-scale prototype). A cambered V-shape depressor is hung below the frame and two bridles are attached at the midpoint of the side frames. A net-release controller is used, which not only controls the net release mechanism but also records the net depth, temperature and flow rate during net towing. The controller sends stored command signals to the net release mechanism as depth settings and/or time settings and does not require any commands from the surface through a conducting cable or by acoustic signals. Two other models were constructed before the construction of the large-scale prototype, which are a small-scale prototype (2 m2 mouth area) for testing the net release mechanism and a 1/4-scale model of the large-scale prototype for flume tank tests. Flume tank tests with the 1/4-scale model showed that the frame leaned forward at a tilt angle from 5 to 15 degrees at towing speeds from 0.8 to 1.4 m s-1. Opened nets closed smoothly and sequentially nets were completely opened when the trigger was released by the command. Net depth rarely changed even during changes in towing speed. Sea trials both by the small-scale and the large-scale prototype demonstrated the same towing characteristics expected from the flume tank tests. The newly developed multiple layer opening/closing MOHT (MOC-MOHT) is considered to be suitable for quantitative layer sampling of juvenile fish.

  15. Aboveground storage tank double bottom cathodic protection

    SciTech Connect

    Surkein, M.B.

    1995-12-31

    Cathodic protection is typically used to achieve corrosion control between bottoms of aboveground storage tanks with double bottoms. To determine the proper design of such systems, an investigation was conducted on the performance of two different cathodic protection system designs utilizing zinc ribbon anodes. A full scale field test on a 35 meter (115 feet) diameter tank was conducted to determine cathodic protection system performance. The test included periodic measurement of tank bottom steel potentials including on, instant off and polarization decay, anode current output and tank product level measurements.Results showed that zinc ribbon anode spacing in a chord fashion of 1.2 meter (4 feet) or less can be effective to achieve cathodic protection according to industry accepted standards. Utilizing the design information gained by the study, a standard sacrificial anode and impressed current anode cathodic protection system has been developed.

  16. Sea bottom topography imaging with SAR

    NASA Technical Reports Server (NTRS)

    Vanderkooij, M. W. A.; Wensink, G. J.; Vogelzang, J.

    1992-01-01

    It is well known that under favorable meteorological and hydrodynamical conditions the bottom topography of shallow seas can be mapped with airborne or spaceborne imaging radar. This phenomenon was observed for the first time in 1969 by de Loor and co-workers in Q-band Side Looking Airborne Radar (SLAR) imagery of sandwaves in the North Sea. It is now generally accepted that the imaging mechanism consists of three steps: (1) interaction between (tidal) current and bottom topography causes spatial modulations in the surface current velocity; (2) modulations in the surface current velocity give rise to variations in the spectrum of wind-generated waves, as described by the action balance equation; and (3) variations in the wave spectrum show up as intensity modulations in radar imagery. In order to predict radar backscatter modulations caused by sandwaves, an imaging model, covering the three steps, was developed by the Dutch Sea Bottom Topography Group. This model and some model results will be shown. On 16 Aug. 1989 an experiment was performed with the polarimetric P-, L-, and C-band synthetic aperture radar (SAR) of NASA/JPL. One scene was recorded in SAR mode. On 12 Jul. 1991 another three scenes were recorded, of which one was in the ATI-mode (Along-Track Interferometer). These experiments took place in the test area of the Sea Bottom Topography Group, 30 km off the Dutch coast, where the bottom topography is dominated by sand waves. In-situ data were gathered by a ship in the test area and on 'Measuring Platform Noordwijk', 20 km from the center of the test area. The radar images made during the experiment were compared with digitized maps of the bottom. Furthermore, the profiles of radar backscatter modulation were compared with the results of the model. During the workshop some preliminary results of the ATI measurements will be shown.

  17. Three-dimensional mapping of red stingray ( Dasyatis akajei) movement with reference to bottom topography

    NASA Astrophysics Data System (ADS)

    Otaki, Takayoshi; Hamana, Masahiro; Tanoe, Hideaki; Miyazaki, Nobuyuki; Shibuno, Takuro; Komatsu, Teruhisa

    2015-06-01

    Most demersal fishes maintain strong relations with bottom substrates and bottom depths and/or topography during their lives. It is important to know these relations to for understand their lives. In Tokyo Bay, red stingray, Dasyatis akajei, classified as near-threatened species by IUCN, has increased since the 1980s. It is a top predator and engages in ecosystem engineer by mixing the sand bed surface through burring behavior, and greatly influences a coastal ecosystem. It is reported that this species invades in plage and tidal flats and has sometimes injured beachgoers and people gathering clams in Tokyo bay. Thus, it is necessary to know its behavior and habitat use to avoid accidents and to better conserve the biodiversity of ecosystems. However, previous studies have not examined its relationship with the bottom environment. This study aims to describe its behavior in relation to the bottom environment. We sounded three dimensional bottom topography of their habitat off Kaneda Cove in Tokyo Bay with interferometric sidescan sonar system and traced the movement of red stingrays by attaching a data logger system to survey their migration. The results revealed that red stingray repeated vertical movement between the surface and bottom, and used not only sand beds but also rocky beds.

  18. 49 CFR 178.970 - Bottom lift test.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 49 Transportation 2 2010-10-01 2010-10-01 false Bottom lift test. 178.970 Section 178.970... Testing of Large Packagings § 178.970 Bottom lift test. (a) General. The bottom lift test must be...) Special preparation for the bottom lift test. The Large Packaging must be loaded to 1.25 times its maximum...

  19. 46 CFR 174.050 - Stability on bottom.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 46 Shipping 7 2012-10-01 2012-10-01 false Stability on bottom. 174.050 Section 174.050 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) SUBDIVISION AND STABILITY SPECIAL RULES... Stability on bottom. Each bottom bearing unit must be designed so that, while supported on the sea bottom...

  20. 46 CFR 174.050 - Stability on bottom.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 46 Shipping 7 2014-10-01 2014-10-01 false Stability on bottom. 174.050 Section 174.050 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) SUBDIVISION AND STABILITY SPECIAL RULES... Stability on bottom. Each bottom bearing unit must be designed so that, while supported on the sea bottom...

  1. Mercury in bottom sediment and aquatic invertebrates, Carson and Truckee River Basins, Nevada and California

    SciTech Connect

    Lawrence, S.J.; Bevans, H.E.

    1994-12-31

    Bottom sediment and aquatic invertebrates were sampled for trace-element analyses at 11 sites in the Carson and Truckee River Basins during September 1 992 as part of the US Geological Survey`s National Water-Quality Assessment Program. Composite bottom-sediment samples from inundated depositional areas were wet-sieved through a 63-micrometer nylon mesh and composite aquatic invertebrate samples were allowed to depurate prior to analyses. In the Carson River Basin, mercury concentrations increased downstream from 0.24 microgram per gram, dry weight ({mu}g/g), in both bottom sediment and western crayfish (Pacifastacus leniusculus) samples from the East Fork Carson River near Markleeville, Calif., to 5.9 {mu}g/g in bottom sediment in the Carson River near Fallon, Nev., and to 48 {mu}g/g in western crayfish in the river near Fort Churchill, Nev. Asiatic clams (Corbicula fluminea) from the Carson River at Fort Churchill and near Fallon had 6.1 and 1.4 {mu}g/g of mercury, respectively. In the Truckee River Basin, mercury concentrations increased downstream from 0.02 {mu}g/g in bottom sediment and 0.17--0.21 {mu}g/g in western crayfish at sites upstream of Reno, Nev., to 0.58 {mu}g/g in bottom sediment and 0.49 {mu}g/g in western crayfish at Clark, Nev. Downstream patterns of mercury concentration in bottom sediment and western crayfish are similar. Possible sources of mercury include historical gold and silver ore-milling activities, acid mine drainage, mineral deposits, and urban activities.

  2. 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.

  3. [Exploitation of the shrimp trawl fishery in the period 1991-1999 at the Gulf of Nicoya, Costa Rica].

    PubMed

    Tabash Blanco, Farid A

    2007-03-01

    In Costa Rica, the Gulf of Nicoya shrimp fishery originated in 1952 and represented one of the most important economic activities in the region. Nevertheless, overfishery reduced the captured volumes to levels that prevent this commercial activity. I analyzed official fishery statistics between 1991 and 1999. These species involved are: two species of white shrimp, (Litopenaeus occidentalis and L. stylirostris), the "titi" shrimp (Xiphopenaeus riveti), the brown shrimp (Farfantepenaeus californiensis), the "pinki" shrimp (F. brevirostris) and the "fidel" shrimp (Solenocera agassizi). All the species reached the Maximum Sustainable Yield in the decades of 1970 and 1980 and are now found at over-exploitation levels. I recommend that this shrimp trawl fishery be completely closed down.

  4. SmeltCam: Underwater Video Codend for Trawled Nets with an Application to the Distribution of the Imperiled Delta Smelt

    PubMed Central

    Feyrer, Frederick; Portz, Donald; Odum, Darren; Newman, Ken B.; Sommer, Ted; Contreras, Dave; Baxter, Randall; Slater, Steven B.; Sereno, Deanna; Van Nieuwenhuyse, Erwin

    2013-01-01

    Studying rare and sensitive species is a challenge in conservation biology. The problem is exemplified by the case of the imperiled delta smelt Hypomesus transpacificus, a small delicate fish species endemic to the San Francisco Estuary, California. Persistent record-low levels of abundance and relatively high sensitivity to handling stress pose considerable challenges to studying delta smelt in the wild. To attempt to overcome these and other challenges we have developed the SmeltCam, an underwater video camera codend for trawled nets. The SmeltCam functions as an open-ended codend that automatically collects information on the number and species of fishes that pass freely through a trawled net without handling. We applied the SmeltCam to study the fine-scale distribution of juvenile delta smelt in the water column in the upper San Francisco Estuary. We learned that during flood tides delta smelt were relatively abundant throughout the water column and that during ebb tides delta smelt were significantly less abundant and occurred only in the lower half and sides of the water column. The results suggest that delta smelt manipulate their position in the water column to facilitate retention in favorable habitats. With the application of the SmeltCam we increased the survival of individual delta smelt by 72% compared to using a traditional codend, where all of the fish would have likely died due to handling stress. The SmeltCam improves upon similar previously developed silhouette photography or video recording devices and demonstrates how new technology can be developed to address important questions in conservation biology as well as lessen the negative effects associated with traditional sampling methods on imperiled species. PMID:23861814

  5. SmeltCam: underwater video codend for trawled nets with an application to the distribution of the imperiled delta smelt.

    PubMed

    Feyrer, Frederick; Portz, Donald; Odum, Darren; Newman, Ken B; Sommer, Ted; Contreras, Dave; Baxter, Randall; Slater, Steven B; Sereno, Deanna; Van Nieuwenhuyse, Erwin

    2013-01-01

    Studying rare and sensitive species is a challenge in conservation biology. The problem is exemplified by the case of the imperiled delta smelt Hypomesus transpacificus, a small delicate fish species endemic to the San Francisco Estuary, California. Persistent record-low levels of abundance and relatively high sensitivity to handling stress pose considerable challenges to studying delta smelt in the wild. To attempt to overcome these and other challenges we have developed the SmeltCam, an underwater video camera codend for trawled nets. The SmeltCam functions as an open-ended codend that automatically collects information on the number and species of fishes that pass freely through a trawled net without handling. We applied the SmeltCam to study the fine-scale distribution of juvenile delta smelt in the water column in the upper San Francisco Estuary. We learned that during flood tides delta smelt were relatively abundant throughout the water column and that during ebb tides delta smelt were significantly less abundant and occurred only in the lower half and sides of the water column. The results suggest that delta smelt manipulate their position in the water column to facilitate retention in favorable habitats. With the application of the SmeltCam we increased the survival of individual delta smelt by 72% compared to using a traditional codend, where all of the fish would have likely died due to handling stress. The SmeltCam improves upon similar previously developed silhouette photography or video recording devices and demonstrates how new technology can be developed to address important questions in conservation biology as well as lessen the negative effects associated with traditional sampling methods on imperiled species.

  6. High-frequency internal waves and thick bottom mixed layers observed by gliders in the Gulf Stream

    NASA Astrophysics Data System (ADS)

    Todd, Robert E.

    2017-06-01

    Autonomous underwater gliders are conducting high-resolution surveys within the Gulf Stream along the U.S. East Coast. Glider surveys reveal two mechanisms by which energy is extracted from the Gulf Stream as it flows over the Blake Plateau, a portion of the outer continental shelf between Florida and North Carolina where bottom depths are less than 1000 m. Internal waves with vertical velocities exceeding 0.1 m s-1 and frequencies just below the local buoyancy frequency are routinely found over the Blake Plateau, particularly near the Charleston Bump, a prominent topographic feature. These waves are likely internal lee waves generated by the subinertial Gulf Stream flow over the irregular bathymetry of the outer continental shelf. Bottom mixed layers with O(100) m thickness are also frequently encountered; these thick bottom mixed layers likely form in the lee of topography due to enhanced turbulence generated by O(1) m s-1 near-bottom flows.

  7. There's Plenty Of Difficulty Near The Bottom

    NASA Astrophysics Data System (ADS)

    Durcan, Mark; Lu, Shifeng

    2007-09-01

    This paper is adapted from a keynote presentation given by Mark Durcan, President and COO of Micron Technology. The keynote presentation used a visionary speech given by Dr. Richard Feynman in 1959 ("There's Plenty of Room at the Bottom") as the launching pad to discuss some of the difficulties associated with manipulating matter at the very small scale.

  8. Frozen water waves over rough topographical bottoms.

    PubMed

    Chen, Liang-Shan; Ye, Zhen

    2004-09-01

    The propagation of surface water waves over rough topographical bottoms is investigated by the multiple scattering theory. It is shown that the waves can be localized spatially through the process of multiple scattering and wave interference, a peculiar wave phenomenon which has been previously discussed for frozen light in optical systems [Nature 390, 661 (1997)

  9. Bottom-strange mesons in hyperonic matter

    NASA Astrophysics Data System (ADS)

    Pathak, Divakar; Mishra, Amruta

    2014-11-01

    The in-medium behavior of bottom-strange pseudoscalar mesons in hot, isospin asymmetric and dense hadronic environment is studied using a chiral effective model. The same was recently generalized to the heavy quark sector and employed to study the behavior of open-charm and open-bottom mesons. The heavy quark (anti-quark) is treated as frozen and all medium modifications of these bottom-strange mesons are due to their strange anti-quark (quark) content. We observe a pronounced dependence of their medium mass on baryonic density and strangeness content of the medium. Certain aspects of these in-medium interactions are similar to those observed for the strange-charmed mesons in a preceding investigation, such as the lifting of mass-degeneracy of BS0 and {\\bar B}S0 mesons in hyperonic matter, while the same is respected in vacuum as well as in nuclear matter. In general, however, there is a remarkable distinction between the two species, even though the formalism predicts a completely analogous in-medium interaction Lagrangian density. We discuss in detail the reason for different in-medium behavior of these bottom-strange mesons as compared to charmed-strange mesons, despite the dynamics of the heavy quark being treated as frozen in both cases.

  10. Structural Influence of Dynamics of Bottom Loads

    DTIC Science & Technology

    2014-02-10

    Engineering and Mechanics P.C. Rossin College of Engineering and Applied Science Lehigh University Bethlehem, PA 18015, USA Abstract: The deformation...over the bottom, c, can be estimated by c = ■ VTT 1 VTT 2tanj3 cos/? 2sin/? (42) where V is the vertical velocity of a 2D wedge dropped in

  11. Spectroscopy and decays of charm and bottom

    SciTech Connect

    Butler, J.N.

    1997-10-01

    After a brief review of the quark model, we discuss our present knowledge of the spectroscopy of charm and bottom mesons and baryons. We go on to review the lifetimes, semileptonic, and purely leptonic decays of these particles. We conclude with a brief discussion B and D mixing and rare decays.

  12. A resting bottom sodium cooled fast reactor

    SciTech Connect

    Costes, D.

    2012-07-01

    This follows ICAPP 2011 paper 11059 'Fast Reactor with a Cold Bottom Vessel', on sodium cooled reactor vessels in thermal gradient, resting on soil. Sodium is frozen on vessel bottom plate, temperature increasing to the top. The vault cover rests on the safety vessel, the core diagrid welded to a toric collector forms a slab, supported by skirts resting on the bottom plate. Intermediate exchangers and pumps, fixed on the cover, plunge on the collector. At the vessel top, a skirt hanging from the cover plunges into sodium, leaving a thin circular slit partially filled by sodium covered by argon, providing leak-tightness and allowing vessel dilatation, as well as a radial relative holding due to sodium inertia. No 'air conditioning' at 400 deg. C is needed as for hanging vessels, and this allows a large economy. The sodium volume below the slab contains isolating refractory elements, stopping a hypothetical corium flow. The small gas volume around the vessel limits any LOCA. The liner cooling system of the concrete safety vessel may contribute to reactor cooling. The cold resting bottom vessel, proposed by the author for many years, could avoid the complete visual inspection required for hanging vessels. However, a double vessel, containing support skirts, would allow introduction of inspecting devices. Stress limiting thermal gradient is obtained by filling secondary sodium in the intermediate space. (authors)

  13. 46 CFR 171.105 - Double bottoms.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... bottom required by this section must be at least the depth at the centerline given by the following equation: D=18.0+0.05(L) inches D=45.7+0.417(L) centimeters where— D=the depth at the centerline in inches...

  14. 46 CFR 171.105 - Double bottoms.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... (centimeters). L=LBP in feet (meters). (f) The line formed by the intersection of the margin plate and the.... EC01MR91.024 (g) A double bottom is not required in a tank that is integral with the hull of a vessel...

  15. 46 CFR 171.105 - Double bottoms.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... (centimeters). L=LBP in feet (meters). (f) The line formed by the intersection of the margin plate and the.... EC01MR91.024 (g) A double bottom is not required in a tank that is integral with the hull of a vessel...

  16. Bottom Up Succession Planning Works Better.

    ERIC Educational Resources Information Center

    Stevens, Paul

    The majority of current succession planning practices reflect the viewpoint of only a linear career direction for ambitious people. They are based on the premise that competent people have and want only one career direction--an upwardly mobile one. In today's work force, however, a "bottom-up" process works better in succession planning. This…

  17. 49 CFR 179.200-13 - Manway ring or flange, pressure relief device flange, bottom outlet nozzle flange, bottom washout...

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... flange, bottom outlet nozzle flange, bottom washout nozzle flange and other attachments and openings. 179....200-13 Manway ring or flange, pressure relief device flange, bottom outlet nozzle flange, bottom washout nozzle flange and other attachments and openings. (a) These attachments shall be fusion welded to...

  18. A Multi-Disciplinary Investigation of the Nature and Predictability of Sediment Resuspension in Shallow Water: Its Effect on Water Column and Bottom Optical Properties

    DTIC Science & Technology

    1999-09-30

    of the distribution of suspended sediment, bottom albedo and microtopography , bottom type, bedforms, hydrodynamics, and particle dynamics...Figure 2) and have been provided to EcoHAB participants. Although a side-scan survey was scheduled for September, hurricane activity and equipment

  19. Methods to ensure optimal off-bottom and drill bit distance under pellet impact drilling

    NASA Astrophysics Data System (ADS)

    Kovalyov, A. V.; Isaev, Ye D.; Vagapov, A. R.; Urnish, V. V.; Ulyanova, O. S.

    2016-09-01

    The paper describes pellet impact drilling which could be used to increase the drilling speed and the rate of penetration when drilling hard rock for various purposes. Pellet impact drilling implies rock destruction by metal pellets with high kinetic energy in the immediate vicinity of the earth formation encountered. The pellets are circulated in the bottom hole by a high velocity fluid jet, which is the principle component of the ejector pellet impact drill bit. The paper presents the survey of methods ensuring an optimal off-bottom and a drill bit distance. The analysis of methods shows that the issue is topical and requires further research.

  20. Modular Tissue Engineering: Engineering Biological Tissues from the Bottom Up.

    PubMed

    Nichol, Jason W; Khademhosseini, Ali

    2009-01-01

    Tissue engineering creates biological tissues that aim to improve the function of diseased or damaged tissues. To enhance the function of engineered tissues there is a need to generate structures that mimic the intricate architecture and complexity of native organs and tissues. With the desire to create more complex tissues with features such as developed and functional microvasculature, cell binding motifs and tissue specific morphology, tissue engineering techniques are beginning to focus on building modular microtissues with repeated functional units. The emerging field known as modular tissue engineering focuses on fabricating tissue building blocks with specific microarchitectural features and using these modular units to engineer biological tissues from the bottom up. In this review we will examine the promise and shortcomings of "bottom-up" approaches to creating engineered biological tissues. Specifically, we will survey the current techniques for controlling cell aggregation, proliferation and extracellular matrix deposition, as well as approaches to generating shape-controlled tissue modules. We will then highlight techniques utilized to create macroscale engineered biological tissues from modular microscale units.

  1. Heat flow through the sea bottom around the Yucatan Peninsula

    NASA Astrophysics Data System (ADS)

    Khutorskoy, M. D.; Fernandez, R.; Kononov, V. I.; Polyak, B. G.; Matveev, V. G.; Rot, A. A.

    1990-02-01

    Heat flow studies were conducted in January-February 1987, off the Atlantic Coast of Mexico on board the R/V Akademik Nikolai Strakhov. Two areas were surveyed, one transecting the Salt Dome Province and the Campeche Canyon, in the Gulf of Mexico, and the other, on the eastern flank of the Yucatan Peninsula. Conductive heat flow through the bottom sediments was determined as the product of vertical temperature gradient and in situ thermal conductivity, measured with a thermal probe using a multithermistor array and real-time processing capabilities. Forward two-dimensional modeling allows us to estimate heat flow variations at both sites from local disturbances and to obtain average heat flow values of 51 mW/m2 for the transect within the Gulf of Mexico and 38 and 69 mW/m2 for two basins within the Yucatan area. Sea bottom relief has a predominant effect over other environmental factors in the scatter of heat flow determination in the Gulf of Mexico.

  2. Heat flow through the sea bottom around the Yucatan Peninsula

    SciTech Connect

    Khutorskoy, M.D.; Kononov, V.I.; Polyak, B.G. ); Fernandez, R. ); Matveev, V.G.; Rot, A.A. )

    1990-02-10

    Heat flow studies were conducted in January-February 1987, off the Atlantic Coast of Mexico on board the R/V Akademik Nikolai Strakhov. Two areas were surveyed, one transecting the Salt Dome Province and the Campeche Canyon, in the Gulf of Mexico, and the other, on the eastern flank of the Yucatan Peninsula. Conductive heat flow through the bottom sediments was determined as the product of vertical temperature gradient and in situ thermal conductivity, measured with a thermal probe using a multithermistor array and real-time processing capabilities. Forward two-dimensional modeling allows one to estimate heat flow variations at both sites from local disturbances and to obtain average heat flow values of 51 mW/m{sup 2} for the transect within the Gulf of Mexico and 38 and 69 mW/m{sup 2} for two basins within the Yucatan area. Sea bottom relief has a predominant effect over other environmental factors in the scatter of heat flow determination in the Gulf of Mexico.

  3. 50 CFR Table 3 (south) to Part 660... - Non-Trawl Rockfish Conservation Areas and Trip Limits for Open Access Gears South of 40°10′ N. Lat.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 50 Wildlife and Fisheries 11 2011-10-01 2011-10-01 false Non-Trawl Rockfish Conservation Areas and Trip Limits for Open Access Gears South of 40°10â² N. Lat. 3 Table 3 (South) to Part 660, Subpart F...) to Part 660, Subpart F—Non-Trawl Rockfish Conservation Areas and Trip Limits for Open Access Gears...

  4. 50 CFR Table 3 (south) to Part 660... - Non-Trawl Rockfish Conservation Areas and Trip Limits for Open Access Gears South of 40°10′ N. Lat.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 50 Wildlife and Fisheries 13 2014-10-01 2014-10-01 false Non-Trawl Rockfish Conservation Areas and Trip Limits for Open Access Gears South of 40°10â² N. Lat. 3 Table 3 (South) to Part 660, Subpart F...) to Part 660, Subpart F—Non-Trawl Rockfish Conservation Areas and Trip Limits for Open Access Gears...

  5. 50 CFR Table 3 (south) to Part 660... - Non-Trawl Rockfish Conservation Areas and Trip Limits for Open Access Gears South of 40°10′ N. Lat.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 50 Wildlife and Fisheries 13 2012-10-01 2012-10-01 false Non-Trawl Rockfish Conservation Areas and Trip Limits for Open Access Gears South of 40°10â² N. Lat. 3 Table 3 (South) to Part 660, Subpart F...) to Part 660, Subpart F—Non-Trawl Rockfish Conservation Areas and Trip Limits for Open Access Gears...

  6. 50 CFR Table 3 (north) to Part 660... - Non-Trawl Rockfish Conservation Areas and Trip Limits for Open Access Gears North of 40°10′ N. Lat.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 50 Wildlife and Fisheries 13 2014-10-01 2014-10-01 false Non-Trawl Rockfish Conservation Areas and Trip Limits for Open Access Gears North of 40°10â² N. Lat. 3 Table 3 (North) to Part 660, Subpart F...) to Part 660, Subpart F—Non-Trawl Rockfish Conservation Areas and Trip Limits for Open Access Gears...

  7. 50 CFR Table 3 (south) to Part 660... - Non-Trawl Rockfish Conservation Areas and Trip Limits for Open Access Gears South of 40°10′ N. Lat.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 50 Wildlife and Fisheries 13 2013-10-01 2013-10-01 false Non-Trawl Rockfish Conservation Areas and Trip Limits for Open Access Gears South of 40°10â² N. Lat. 3 Table 3 (South) to Part 660, Subpart F...) to Part 660, Subpart F—Non-Trawl Rockfish Conservation Areas and Trip Limits for Open Access Gears...

  8. 50 CFR Table 3 (north) to Part 660... - Non-Trawl Rockfish Conservation Areas and Trip Limits for Open Access Gears North of 40°10′ N. Lat.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 50 Wildlife and Fisheries 13 2012-10-01 2012-10-01 false Non-Trawl Rockfish Conservation Areas and Trip Limits for Open Access Gears North of 40°10â² N. Lat. 3 Table 3 (North) to Part 660, Subpart F...) to Part 660, Subpart F—Non-Trawl Rockfish Conservation Areas and Trip Limits for Open Access Gears...

  9. 50 CFR Table 3 (north) to Part 660... - Non-Trawl Rockfish Conservation Areas and Trip Limits for Open Access Gears North of 40°10′ N. Lat.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 50 Wildlife and Fisheries 11 2011-10-01 2011-10-01 false Non-Trawl Rockfish Conservation Areas and Trip Limits for Open Access Gears North of 40°10â² N. Lat. 3 Table 3 (North) to Part 660, Subpart F...) to Part 660, Subpart F—Non-Trawl Rockfish Conservation Areas and Trip Limits for Open Access Gears...

  10. 50 CFR Table 3 (north) to Part 660... - Non-Trawl Rockfish Conservation Areas and Trip Limits for Open Access Gears North of 40°10′ N. Lat.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 50 Wildlife and Fisheries 13 2013-10-01 2013-10-01 false Non-Trawl Rockfish Conservation Areas and Trip Limits for Open Access Gears North of 40°10â² N. Lat. 3 Table 3 (North) to Part 660, Subpart F...) to Part 660, Subpart F—Non-Trawl Rockfish Conservation Areas and Trip Limits for Open Access Gears...

  11. Benthic litter distribution on circalittoral and deep sea bottoms of the southern Bay of Biscay: Analysis of potential drivers

    NASA Astrophysics Data System (ADS)

    Lopez-Lopez, L.; González-Irusta, J. M.; Punzón, A.; Serrano, A.

    2017-07-01

    We analyze marine litter densities in soft bottoms of the southern Bay of Biscay using five years of demersal trawling data (2006-2010). Marine litter densities amounted to 43 ± 33 kg km-2 and 74 ± 28 items km-2, with plastics and fisheries derived litter being the most widespread categories. Litter densities generally decreased along the water depth axis. To identify possible drivers for the observed litter distribution we performed a generalised additive model, which explained 14.8% of the variance and pointed to densely populated areas, number of fishing ports, geographical sector and fishing activity as the main explanatory factors. The most important driver for the benthic litter distribution was human population, as litter density linearly increased along this variable. Similarly, the number of ports in neighbouring areas had a positive effect on litter densities. Fishing effort had a negative and non-linear effect on benthic litter density which could be explained by litter delocalization during fishing operations. We hypothesise that litter might accumulate preferentially on the periphery of rocky bottoms, out of reach for our sampling methodology. Litter distribution differed among geographical sectors, pointing to other variables such as shipping traffic and oceanographic currents, which were not explicitly considered in the analysis. Our study sets a reference level for benthic macro-litter in the southern Bay of Biscay and identifies factors driving its distribution, which can be extrapolated to other continental shelf seas. Our findings lay the foundations to develop measures aiming to reduce macro-litter densities on the seafloor.

  12. Ocean Bottom Seismometers technology: current state and future outlook

    NASA Astrophysics Data System (ADS)

    Ilinskiy, Dmitry; Ganzha, Oleg

    2016-04-01

    conditions, since it minimizes working time, hence cuts the costs related to the expensive ship time. One of the major factors of success is the development of a reliable pop-up mechanism, which includes not only unfailing hydro-acoustic communication, but also a reliable disconnector, both electrochemical and mechanical that could be used in salt and sweet waters. The extensive operational experience helped us to determine the reasons for non-emersion of the stations. The main problem was a sucking of instruments by muddy bottom sediments, and a simple spring assembly can release the station from the anchor with high probability Secondly, the newly developed software provides the great opportunity to reduce considerably the processing and interpretation time cycle. The calculation of forward kinematic problems can be performed on the notebook in seconds. Visualization tools render color images of gathers with various processing parameters. All mentioned above are proved by real data acquired by GNS during active and passive seismic surveys in deep and shallow waters. GNS has the pool of 65 OBS for large scale crustal 2D/3D active or passive experiments in any part World Ocean.

  13. Constructing bottom barriers with met grouting

    SciTech Connect

    Shibazaki, M.; Yoshida, H.

    1997-12-31

    Installing a bottom barrier using conventional high pressure jetting technology and ensuring barrier continuity is challenging. This paper describes technology that has been developed and demonstrated for the emplacement of bottom barriers using pressures and flow rates above the conventional high pressure jetting parameters. The innovation capable of creating an improved body exceeding 5 meters in diameter has resulted in the satisfying connection and adherence between the treated columns. Besides, the interfaces among the improved bodies obtain the same strength and permeability lower than 1 x 10{sup -7} cm/sec as body itself. A wide variety of the thickness and the diameter of the improved mass optimizes the application, and the method is nearing completion. The paper explains an aspect and briefs case histories.

  14. Short-wavelength bottom-emitting VCSELs

    NASA Astrophysics Data System (ADS)

    Choquette, Kent D.; Barton, Jonathon S.; Geib, Kent M.; Allerman, Andrew A.; Hindi, Jana J.

    1999-04-01

    The fabrication and performance of selectively oxidized 850 nm vertical cavity surface emitting laser (VCSEL) diodes which emit through transparent GaP substrates is reported. Emission through the substrate is advantageous for many VCSEL configurations, such as for the incorporation of optical elements in the substrate or flip-chip integration to microelectronic circuitry. The short wavelength bottom- emitting VCSELs are fabricated by wafer fusion using an inert gas low temperature annealing process. The electrical characteristics of n- and p-type GaAs/GaAs and GaAs/GaP wafer bonded interfaces have been examined to optimize the annealing temperature. A significant reduction of the current-voltage characteristics of the VCSELs bonded to GaP substrates has been achieved whereby the bottom-emitting VCSELs show similar threshold voltage as compared to top- emitting lasers.

  15. Bottom-up design of biomimetic assemblies.

    PubMed

    Tu, Raymond S; Tirrell, Matthew

    2004-09-22

    Nature has evolved the ability to assemble a variety of molecules into functional architectures that can specifically bind cellular ligands. Mimicking this strategy requires the design of a set of multifaceted molecules, where elements that direct assembly were conjugated to biologically specific components. The development of functional molecular building-blocks that assemble to form compartments for therapeutics addresses the desire to have controllable morphologies that interact with biological interfaces at nanometer length scales. The practical application of such 'bottom-up' assemblies requires the ability to predict the type of aggregated structure and to synthesize molecules in a highly controlled fashion. This bottom-up approach results in a molecular platform that mimics biological systems with potential for encapsulating and delivering drug molecules.

  16. PARKA II-A Bottom Loss Measurements

    DTIC Science & Technology

    1970-06-29

    obvious %ngle dependance between 15 to 85 degraes and, appear to be only slightly dependent of frequency; showing an approximate 2 db difference in mean... dependance . between 15 to 85 degrees and indicates a slight frequency dependance of 2 db over the frequency rang3e. The major reflected energy is from the...the low CONFIDENTIAL 10 NUSL Tech Memo 2211-023-70 CONFIDENTIAL sound v Locity sediment, resulting in significant angular dependance of bottom Loss at

  17. Bottom Interaction in Long Range Acoustic Propagation

    DTIC Science & Technology

    2009-09-30

    model calculations (RR, RSR, RBR, SRBR ray paths and the mode-like finale region), 2) deep shadow zone arrivals arising from the spread of energy below...arrivals near 75Hz were observed on bottom-mounted hydrophones in the shadow zone well below the SOFAR channel. Dushaw et al (1999) note: "This...explain the energy in the shadow zones: 1) energy is scattered from internal waves and fine structure in the ocean, or 2) long range sound propagation

  18. Bottom Interaction in Ocean Acoustic Propagation

    DTIC Science & Technology

    2013-09-30

    induced by ocean internal waves, internal tides and mesoscale processes, and by bathymetric features including seamounts and ridges, on the stability...from Seamount B and reflected from the sea surface back down to the seafloor receivers (Figures 1 to 3). We call these bottom-diffracted surface...shipping noise. For example, the DSFAs observed on NPAL04 provided a mechanism for taking long-range energy from 4250m depth into the deep shadow

  19. Bottom Interaction in Ocean Acoustic Propagation

    DTIC Science & Technology

    2014-09-30

    seamounts and ridges, on the stability, statistics, spatial distribution and predictability of broadband acoustic signals..." (quote from the Ocean...2013) attributed some of these arrivals to bottom-diffracted, surface-reflected (BDSR) energy that scattered from a seamount near the Deep VLA and...identified four seafloor diffractors (Figure 1). Three of these (A-C) correspond to small seamounts on the seafloor. Diffractor D however does not

  20. Hydraulic potential in Lake Michigan bottom sediments

    USGS Publications Warehouse

    Cartwright, K.; Hunt, C.S.; Hughes, G.M.; Brower, R.D.

    1979-01-01

    The magnitude and direction of groundwater flux in the bottom sediments of Lake Michigan were deduced from measurements made during three shipboard cruises between 1973 and 1975. These factors affect the geochemical environment of the sediments and therefore the distribution of trace elements reported to be present. The near-shore, sandy-bottom and fine-grained, soft, deep-lake sediments were investigated; areas of hard till or bedrock were not included in the study. Thirty-three piezometers were placed in near-shore sands in waters 5-15 m deep. The piezometers were placed an average of 3 m into the bottom sediment. Water levels from the piezometers averaged 0.6 cm above the lake level, equivalent to an upward hydraulic gradient of about 0.002 cm/cm. Water samples taken from the piezometers have a distinctly different chemical composition from that of the lake water. The total dissolved mineral content and hardness of the groundwater are about twice those of the lake water. Twenty-two hydraulic gradient measurements were made in the fine-grained soft deep-lake sediments in waters 48-140 m deep by using a differential-pressure transducer dropped into the sediments. These measurements show an upward gradient averaging 0.2 cm/cm. No chemical data were obtained for the groundwater in the deep-lake sediments. The results of this study indicate that the groundwater flux is upward through the bottom sediments into Lake Michigan and that there is a chemical change in the water near the water-sediment contact. ?? 1979.

  1. Investigating bottom-up auditory attention

    PubMed Central

    Kaya, Emine Merve; Elhilali, Mounya

    2014-01-01

    Bottom-up attention is a sensory-driven selection mechanism that directs perception toward a subset of the stimulus that is considered salient, or attention-grabbing. Most studies of bottom-up auditory attention have adapted frameworks similar to visual attention models whereby local or global “contrast” is a central concept in defining salient elements in a scene. In the current study, we take a more fundamental approach to modeling auditory attention; providing the first examination of the space of auditory saliency spanning pitch, intensity and timbre; and shedding light on complex interactions among these features. Informed by psychoacoustic results, we develop a computational model of auditory saliency implementing a novel attentional framework, guided by processes hypothesized to take place in the auditory pathway. In particular, the model tests the hypothesis that perception tracks the evolution of sound events in a multidimensional feature space, and flags any deviation from background statistics as salient. Predictions from the model corroborate the relationship between bottom-up auditory attention and statistical inference, and argues for a potential role of predictive coding as mechanism for saliency detection in acoustic scenes. PMID:24904367

  2. 50 CFR Table 2 (south) to Part 660... - Non-Trawl Rockfish Conservation Areas and Trip Limits for Limited Entry Fixed Gear South of 40°10...

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... Trip Limits for Limited Entry Fixed Gear South of 40°10â² N. Lat. 2 Table 2 (South) to Part 660... Table 2 (South) to Part 660, Subpart E—Non-Trawl Rockfish Conservation Areas and Trip Limits for Limited Entry Fixed Gear South of 40°10′ N. Lat. ER30JN11.002 ER30JN11.003 ...

  3. 50 CFR Table 1 (south) to Part 660... - 2010 Trip Limits for Limited Entry Trawl Gear South of 40°10′ N. Lat.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 50 Wildlife and Fisheries 9 2010-10-01 2010-10-01 false 2010 Trip Limits for Limited Entry Trawl Gear South of 40°10â² N. Lat. 1 Table 1 (South) to Part 660, Subpart D Wildlife and Fisheries FISHERY...) FISHERIES OFF WEST COAST STATES Pt. 660, Subpt. D, Table 1 Table 1 (South) to Part 660, Subpart D—2010 Trip...

  4. 50 CFR Table 3 (south) to Part 660... - 2010 Trip Limits for Limited Entry Trawl Gear South of 40°10′ N. Lat.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 50 Wildlife and Fisheries 9 2010-10-01 2010-10-01 false 2010 Trip Limits for Limited Entry Trawl Gear South of 40°10â² N. Lat. 3 Table 3 (South) to Part 660, Subpart G Wildlife and Fisheries FISHERY...) FISHERIES OFF WEST COAST STATES Pt. 660, Subpt. G, Table 3 Table 3 (South) to Part 660, Subpart G—2010 Trip...

  5. 50 CFR Table 1 (north) to Part 660... - 2010 Trip Limits for Limited Entry Trawl Gear North of 40°10′ N. Lat.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 50 Wildlife and Fisheries 9 2010-10-01 2010-10-01 false 2010 Trip Limits for Limited Entry Trawl Gear North of 40°10â² N. Lat. 1 Table 1 (North) to Part 660, Subpart D Wildlife and Fisheries FISHERY...) FISHERIES OFF WEST COAST STATES Pt. 660, Subpt. D, Table 1 Table 1 (North) to Part 660, Subpart D—2010 Trip...

  6. 50 CFR Table 3 (north) to Part 660... - 2010 Trip Limits for Limited Entry Trawl Gear North of 40°10′ N. Lat.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 50 Wildlife and Fisheries 9 2010-10-01 2010-10-01 false 2010 Trip Limits for Limited Entry Trawl Gear North of 40°10â² N. Lat. 3 Table 3 (North) to Part 660, Subpart G Wildlife and Fisheries FISHERY...) FISHERIES OFF WEST COAST STATES Pt. 660, Subpt. G, Table 3 Table 3 (North) to Part 660, Subpart G—2010 Trip...

  7. 50 CFR Table 1 (north) to Part 660... - Limited Entry Trawl Rockfish Conservation Areas and Landing Allowances for non-IFQ Species and...

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 50 Wildlife and Fisheries 11 2011-10-01 2011-10-01 false Limited Entry Trawl Rockfish Conservation Areas and Landing Allowances for non-IFQ Species and Pacific Whiting North of 40°10â² N. Lat. 1 Table 1... Conservation Areas and Landing Allowances for non-IFQ Species and Pacific Whiting North of 40°10′ N. Lat...

  8. 50 CFR Table 1 (south) to Part 660... - Limited Entry Trawl Rockfish Conservation Areas and Landing Allowances for non-IFQ Species and...

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 50 Wildlife and Fisheries 11 2011-10-01 2011-10-01 false Limited Entry Trawl Rockfish Conservation Areas and Landing Allowances for non-IFQ Species and Pacific Whiting South of 40°10â² N. Lat. 1 Table 1... Conservation Areas and Landing Allowances for non-IFQ Species and Pacific Whiting South of 40°10′ N. Lat...

  9. Quality of bottom material and elutriates in the lower Willamette River, Portland Harbor, Oregon

    SciTech Connect

    Fuhrer, G.J.

    1989-01-01

    In October 1983 the US Geological Survey, in cooperation with the US Army Corp of Engineers, collected bottom-material and water samples from Portland Harbor, Oregon to determine concentrations of trace metals and organic compounds in elutriate-test filtrate and bottom material. Of the trace metals examined in bottom material, concentrations of cadmium slightly exceed those of local rocks, whereas lead and zinc exceedance is substantially larger. Of the organochlorine compounds examined in bottom material chlordane, DDD, DDE, DDT, dieldrin, and polychlorinated biphenyls (PCB's) were detected and quantified in at least 30% of the samples tested. A large DDT concentrations near Doane Lake outlet is indicative of recent contamination. Polychlorinated biphenyls are ubiquitous in bottom sediments; median concentrations are nearly 65 micrograms/kilogram and as large as 550 microgram/kilogram PCB loading to the Columbia River from Willamette River suspended sediment has been estimated to be 72 kilograms/year, nearly five times the PCB dredge load of 15 kilogram/year. The acid and base-neutral extractable di-n-butyl phthalate and bis (2-methylhexyl)phthalate occur in sediments of Terminal No. 2 in concentrations as large as 1,965 and 2,200 micrograms/ kilogram, respectively. Of the trace metals examined in both standard and oxic elutriate-test filtrate, only copper concentration in an oxic elutriate-test filtrate exceeded the water quality criteria. 34 refs., 8 figs., 12 tabs.

  10. 24. PIN CONNECTION AT VERTICAL AND BOTTOM CHORD ON CAMELBACK ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    24. PIN CONNECTION AT VERTICAL AND BOTTOM CHORD ON CAMELBACK THROUGH TRUSS. VERTICAL AND BOTTOM CHORD MADE OF HAND-FORGED EYE BARS - New River Bridge, Spanning New River at State Route 623, Pembroke, Giles County, VA

  11. 12. DETAIL VIEW OF BOTTOM CHORD CONNECTION AT THIRD PANAL ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    12. DETAIL VIEW OF BOTTOM CHORD CONNECTION AT THIRD PANAL POINT IN FROM ABUTMENT. NOTE THAT THE BOTTOM CHORD IS CONTINUOUS ACROSS THE CONNECTION - Poffenberger Road Bridge, Spanning Catoctin Creek, Middletown, Frederick County, MD

  12. 1. Entrance to Heintooga Round Bottom Road and sign looking ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    1. Entrance to Heintooga Round Bottom Road and sign looking N. - Great Smoky Mountains National Park Roads & Bridges, Heintooga Round Bottom Road & Balsam Mountain Road, Between Blue Ridge Parkway & Big Cove Road, Gatlinburg, Sevier County, TN

  13. 49 CFR 178.970 - Bottom lift test.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... gross mass, the load being evenly distributed. (c) Test method. All Large Packaging design types must be... 49 Transportation 3 2013-10-01 2013-10-01 false Bottom lift test. 178.970 Section 178.970... Packagings § 178.970 Bottom lift test. (a) General. The bottom lift test must be conducted for...

  14. 49 CFR 178.811 - Bottom lift test.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... Bottom lift test. (a) General. The bottom lift test must be conducted for the qualification of all IBC.... (c) Test method. All IBC design types must be raised and lowered twice by a lift truck with the forks... 49 Transportation 3 2011-10-01 2011-10-01 false Bottom lift test. 178.811 Section...

  15. 49 CFR 178.811 - Bottom lift test.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... evenly distributed. (c) Test method. All IBC design types must be raised and lowered twice by a lift... 49 Transportation 2 2010-10-01 2010-10-01 false Bottom lift test. 178.811 Section 178.811... Testing of IBCs § 178.811 Bottom lift test. (a) General. The bottom lift test must be conducted for...

  16. 49 CFR 178.811 - Bottom lift test.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... Bottom lift test. (a) General. The bottom lift test must be conducted for the qualification of all IBC.... (c) Test method. All IBC design types must be raised and lowered twice by a lift truck with the forks... 49 Transportation 3 2013-10-01 2013-10-01 false Bottom lift test. 178.811 Section...

  17. 4. Aerial view southwest, Adams Dam Road bottom left, State ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    4. Aerial view southwest, Adams Dam Road bottom left, State Route 100 center, back gates to Winterthur and Wilmington Country Club upper center, duck pond and reservoir bottom right and center, and State Route 92 center bottom. - Winterthur Farms, Intersection State Routes 92 & 100, Intersection State Routes 92 & 100, Winterthur, New Castle County, DE

  18. 3. Aerial view southeast, State Route 92 bottom left, Adams ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    3. Aerial view southeast, State Route 92 bottom left, Adams Dam Road center, Brandywine Creek State Park and J. Chandler Farm in center left, duck pond bottom right and reservoir bottom left. - Winterthur Farms, Intersection State Routes 92 & 100, Intersection State Routes 92 & 100, Winterthur, New Castle County, DE

  19. 46 CFR 174.050 - Stability on bottom.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... PERTAINING TO SPECIFIC VESSEL TYPES Special Rules Pertaining to Mobile Offshore Drilling Units § 174.050 Stability on bottom. Each bottom bearing unit must be designed so that, while supported on the sea bottom... subjected to the forces of wave and current and to wind blowing at the velocities described in §...

  20. 46 CFR 171.106 - Wells in double bottoms.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 46 Shipping 7 2012-10-01 2012-10-01 false Wells in double bottoms. 171.106 Section 171.106... PERTAINING TO VESSELS CARRYING PASSENGERS Additional Subdivision Requirements § 171.106 Wells in double bottoms. (a) This section applies to each vessel that has a well installed in a double bottom required...

  1. 46 CFR 171.106 - Wells in double bottoms.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 46 Shipping 7 2010-10-01 2010-10-01 false Wells in double bottoms. 171.106 Section 171.106... PERTAINING TO VESSELS CARRYING PASSENGERS Additional Subdivision Requirements § 171.106 Wells in double bottoms. (a) This section applies to each vessel that has a well installed in a double bottom required...

  2. 46 CFR 171.106 - Wells in double bottoms.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 46 Shipping 7 2013-10-01 2013-10-01 false Wells in double bottoms. 171.106 Section 171.106... PERTAINING TO VESSELS CARRYING PASSENGERS Additional Subdivision Requirements § 171.106 Wells in double bottoms. (a) This section applies to each vessel that has a well installed in a double bottom required...

  3. 46 CFR 171.106 - Wells in double bottoms.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 46 Shipping 7 2014-10-01 2014-10-01 false Wells in double bottoms. 171.106 Section 171.106... PERTAINING TO VESSELS CARRYING PASSENGERS Additional Subdivision Requirements § 171.106 Wells in double bottoms. (a) This section applies to each vessel that has a well installed in a double bottom required...

  4. Epibenthic assemblages of the Tail of the Grand Bank and Flemish Cap (northwest Atlantic) in relation to environmental parameters and trawling intensity

    NASA Astrophysics Data System (ADS)

    Murillo, Francisco Javier; Serrano, Alberto; Kenchington, Ellen; Mora, José

    2016-03-01

    The structure, composition and distribution of epibenthic invertebrate assemblages on the Tail of the Grand Bank of Newfoundland and Flemish Cap (northwest Atlantic) were sampled using depth-stratified trawls. Faunal analysis of 152 uniquely identified taxa produced hierarchical synoptic tables of species associations with diagnostic indicators based on species fidelity. Twelve spatially coherent epibenthic megafaunal assemblages were identified, each with relatively sharp faunal boundaries and unique species attributes. These assemblages were shown a posteriori through ANOSIM to have statistically different species compositions, and were nested within three major regional-scale faunal groups: (I) the continental shelf of the Tail of the Grand Bank, typified by the sea cucumber Cucumaria frondosa and the sand dollar Echinarachnius parma; (II) the upper slope of the Grand Bank and top of Flemish Cap, typified by the sponges Radiella hemisphaerica and Iophon piceum and the sea star Ceramaster granularis; and (III) the lower slope of the Grand Bank and Flemish Cap, typified by the sea urchin Phormosoma placenta, and the sea pens Anthoptilum grandiflorum and Funiculina quadrangularis. Comparisons with literature on benthic species associations from a half century ago suggest that the assemblages identified herein have persisted in the area at least for decades. Detrended correspondence analysis (DCA) identified a well-defined biological gradient along the first axis with very high species turn-over. Ten environmental variables (including Trawling Intensity) were significantly correlated with the ordinated data. At one extreme the continental shelf faunal group (I) was associated with shallow depth (mostly, less than 200 m), coarse sediments and cold and fresh water associated with the Labrador Current. At the other extreme the lower slope faunal group (III; stations below 500-600 m throughout the study area) was strongly associated with deep water, muddy sediments, and

  5. Chemical data for bottom sediment in Mountain Creek Lake, Dallas, Texas, 1999-2000

    USGS Publications Warehouse

    Wilson, Jennifer T.

    2002-01-01

    Mountain Creek Lake is a reservoir adjacent to the Naval Weapons Industrial Reserve Plant and the former Naval Air Station in Dallas, Texas. The U.S. Geological Survey began studies of water, sediment, and biota in the reservoir in 1994 after a Resource Conservation and Recovery Act Facility Investigation detected concentrations of organic chemicals on both facilities. Additional reservoir bottom sediment samples were collected during December 1999–January 2000 at the request of the Southern Division Naval Facilities Engineering Command to further define the occurrence and distribution of selected constituents and to supplement available data. The U.S. Geological Survey National Water Quality Laboratory analyzed bottom-sediment samples from 16 box cores and 5 gravity cores for major and trace elements, organochlorine pesticides, polychlorinated biphenyls, polycyclic aromatic hydrocarbons, grain size, and cesium-137.

  6. Rankine bottoming cycle safety analysis. Final report

    SciTech Connect

    Lewandowski, G.A.

    1980-02-01

    Vector Engineering Inc. conducted a safety and hazards analysis of three Rankine Bottoming Cycle Systems in public utility applications: a Thermo Electron system using Fluorinal-85 (a mixture of 85 mole % trifluoroethanol and 15 mole % water) as the working fluid; a Sundstrand system using toluene as the working fluid; and a Mechanical Technology system using steam and Freon-II as the working fluids. The properties of the working fluids considered are flammability, toxicity, and degradation, and the risks to both plant workers and the community at large are analyzed.

  7. Development of Bottom Oil Recovery Systems. Revised

    DTIC Science & Technology

    2014-02-01

    designed a recovery system based on dredging technology. It could handle harsh wind /wave conditions but has significant logistical requirements, due...Knots m/s Meter(s) per second M/T Motor tanker M/V Motor vessel m Meter or meters m2 Square meters m3 Cubic meters MBTA Migratory Bird ...usable for some bottom types. Wind 30 kts (45-kt gusts) Wave 0-2m (0-5ft) Current 0-2 kts Lightning ɝmiles Minimum depth of about 9m (30 ft

  8. Bottom quark mass from {Upsilon} mesons

    SciTech Connect

    Hoang, A.H.

    1999-01-01

    The bottom quark pole mass M{sub b} is determined using a sum rule which relates the masses and the electronic decay widths of the {Upsilon} mesons to large {ital n} moments of the vacuum polarization function calculated from nonrelativistic quantum chromodynamics. The complete set of next-to-next-to-leading order [i.e., O({alpha}{sub s}{sup 2},{alpha}{sub s}v,v{sup 2}) where v is the bottom quark c.m. velocity] corrections is calculated and leads to a considerable reduction of theoretical uncertainties compared to a pure next-to-leading order analysis. However, the theoretical uncertainties remain much larger than the experimental ones. For a two parameter fit for M{sub b}, and the strong M{bar S} coupling {alpha}{sub s}, and using the scanning method to estimate theoretical uncertainties, the next-to-next-to-leading order analysis yields 4.74 GeV {le}M{sub b}{le}4.87 GeV and 0.096{le}{alpha}{sub s}(M{sub z}){le}0.124 if experimental uncertainties are included at the 95{percent} confidence level and if two-loop running for {alpha}{sub s} is employed. M{sub b} and {alpha}{sub s} have a sizable positive correlation. For the running M{bar S} bottom quark mass this leads to 4.09 GeV {le}m{sub b}(M{sub {Upsilon}(1S)}/2){le}4.32 GeV. If {alpha}{sub s} is taken as an input, the result for the bottom quark pole mass reads 4.78 GeV {le}M{sub b}{le}4.98 GeVthinsp[4.08 GeV {le}m{sub b}(M{sub {Upsilon}(1S)}/2){le}4.28 GeV] for 0.114{le}{alpha}{sub s}(M{sub z}){le}0.122. The discrepancies between the results of three previous analyses on the same subject by Voloshin, Jamin, and Pich and K{umlt u}hn {ital et al.} are clarified. A comprehensive review on the calculation of the heavy-quark{endash}antiquark pair production cross section through a vector current at next-to-next-to leading order in the nonrelativistic expansion is presented. {copyright} {ital 1998} {ital The American Physical Society}

  9. Peach bottom recirculation piping replacement ALARA program

    SciTech Connect

    Englesson, G.A.; Hilsmeier, A.E.; Mann, B.J.

    1986-01-01

    In late 1983, Philadelphia Electric Company (PECo) began detailed planning to replace the recirculation, residual heat removal, and part of the reactor water cleanup piping of the Peach Bottom Unit 2 reactor. Included in this work was an estimate of the collective exposure expected during piping replacement. That initial estimate, 1945 man-rem, is compared with the actual collective dose incurred during the piping replacement program. Also included are the exposures incurred during two additional tasks (safe end replacement and recirculation pump disassembly and decontamination) not considered in the initial estimate.

  10. A new kind of bottom quark factory

    SciTech Connect

    Mtingwa, S.K. . High Energy Physics Div.); Strikman, M. AN SSSR, Leningrad . Inst. Yadernoj Fiziki)

    1991-01-01

    We describe a novel method of producing large numbers of B mesons containing bottom quarks. It is known that one should analyze at least 10{sup 9} B meson decays to elucidate the physics of CP violation and rare B decay modes. Using the ultra high energy electron beams from the future generation of electron linear colliders, we Compton backscatter low energy laser beams off these electron beams. From this process, we produce hot photons having energy hundreds of GeV. Upon scattering these hot photons onto stationary targets, we show that it is possible to photoproduce and measure the necessary 10{sup 9} B mesons per year. 24 refs., 4 figs.

  11. Marine debris survey manual. Final report

    SciTech Connect

    Ribic, C.A.; Dixon, T.R.; Vining, I.; Duke, M.

    1991-10-01

    Over the last several years, concern has increased about the amount of man-made materials lost or discarded at sea and the potential impacts to the environment. The scope of the problem depends on the amounts and types of debris. One problem is making a regional comparison of debris is the lack of a standard methodology. The objective of this manual is to discuss designs and methodologies for assessment studies of marine debris. This manual has been written for managers, researchers, and others who are just entering this area of study and who seek guidance in designing marine debris surveys. Active researchers will be able to use this manual along with applicable references herein as a source for design improvement. To this end, the authors have reviewed and synthesized survey techniques that have been used in the past for assessing marine debris, such as sighting surveys, beach surveys, and trawl surveys, and have considered new methods (e.g., aerial photography). All techniques have been put into a general survey planning framework to assist in developing different marine debris surveys.

  12. Regional Geology of the Southern Lake Erie (Ohio) Bottom: A Seismic Reflection and Vibracore Study.

    DTIC Science & Technology

    1982-12-01

    GEOLOGIC HISTORY 1. Introduction. Sedimentary deposits from the Devonian and the Quaternary periods are exposed in the study area. The Devonian Ohio...TITLE (and Subtitle) S. TYPE OF REPORT & PERIOD COVERED REGIONAL GEOLOGY OF THE SOUTHERN LAKE ERIE (OHIO) Miscellaneous Report BOTTOM: A SEISMIC...CLASSIFICATION OF THIS PAG(WIlm Date Egntered) Devonian shale overlain by Quaternary glacial tills and postglacial deposits underlies most of the survey area

  13. The Earnings Ladder. Who's at the Bottom? Who's at the Top? Statistical Brief.

    ERIC Educational Resources Information Center

    Bureau of the Census (DOC), Washington, DC. Economics and Statistics Administration.

    Data collected by the March Current Population Survey were used to identify which groups of year-round, full-time civilian workers aged 16 and older were most likely to be at the top and bottom of the earnings ladder. Women, young workers, less-educated individuals, and Hispanics were most likely to earn less than $13,091 (1992 constant dollars),…

  14. Heavy exotic molecules with charm and bottom

    NASA Astrophysics Data System (ADS)

    Liu, Yizhuang; Zahed, Ismail

    2016-11-01

    We revisit the formation of pion-mediated heavy-light exotic molecules with both charm and bottom and their chiral partners under the general strictures of both heavy-quark and chiral symmetry. The chiral exotic partners with good parity formed using the (0+ ,1+) multiplet are about twice more bound than their primary exotic partners formed using the (0- ,1-) multiplet. The chiral couplings across the multiplets (0± ,1±) cause the chiral exotic partners to unbind, and the primary exotic molecules to be about twice more bound, for J ≤ 1. Our multi-channel coupling results show that only the charm isosinglet exotic molecules with JPC =1++ bind, which we identify as the reported neutral X (3872). Also, the bottom isotriplet exotic with JPC =1+- binds, which we identify as a mixture of the reported charged exotics Zb+ (10610) and Zb+ (10650). The bound isosinglet with JPC =1++ is suggested as a possible neutral Xb (10532) not yet reported.

  15. Charmed bottom baryon spectroscopy from lattice QCD

    DOE PAGES

    Brown, Zachary S.; Detmold, William; Meinel, Stefan; ...

    2014-11-19

    In this study, we calculate the masses of baryons containing one, two, or three heavy quarks using lattice QCD. We consider all possible combinations of charm and bottom quarks, and compute a total of 36 different states with JP = 1/2+ and JP = 3/2+. We use domain-wall fermions for the up, down, and strange quarks, a relativistic heavy-quark action for the charm quarks, and nonrelativistic QCD for the bottom quarks. Our analysis includes results from two different lattice spacings and seven different pion masses. We perform extrapolations of the baryon masses to the continuum limit and to the physicalmore » pion mass using SU(4|2) heavy-hadron chiral perturbation theory including 1/mQ and finite-volume effects. For the 14 singly heavy baryons that have already been observed, our results agree with the experimental values within the uncertainties. We compare our predictions for the hitherto unobserved states with other lattice calculations and quark-model studies.« less

  16. The sea bottom temperature offshore southwestern Taiwan

    NASA Astrophysics Data System (ADS)

    Chiang, H.; Shyu, C.; Peng, Y.; Chang, H.; Chen, S.; Chung, S.; Wang, Y.

    2012-12-01

    The sea bottom temperature (SBT) is important to apply to the heat flow estimation by BSR. Also the SBT may response the fluid migration near subsurface. Here we present 150 measurements of SBT offshore southwestern Taiwan where abundant gas hydrates has been evaluated. The SBT data were acquired by the heat probe with high resolution up to 0.0001°C. Thermal gradients were determined from several temperature sensors installed in different depth in the heat probe and then the SBT could be calculated by extrapolation. The results show that the SBT are between 2.23 and 10.14°C in water depth within the range of 409 to 3248 meters. Basically, the SBT is inversely hyperbolic proportional to the water depth for those 132 measurements the water depth are shallower than 2650 meters. The product of SBT and water depth has an average of 4419 m-°C and a standard deviation of 402 m-°C. However the SBT of others 18 measurements in the deep water region are scattered without any significant trend. Some measurements near mud diapirs in the shallow water have high anomaly SBT. It is suggested that the fluid from deep underground may migrate along the fractures or faults related to the movements of the mud volume.; The sea bottom temperature offshore southwestern Taiwan

  17. Bottom-up holographic approach to QCD

    SciTech Connect

    Afonin, S. S.

    2016-01-22

    One of the most known result of the string theory consists in the idea that some strongly coupled gauge theories may have a dual description in terms of a higher dimensional weakly coupled gravitational theory — the so-called AdS/CFT correspondence or gauge/gravity correspondence. The attempts to apply this idea to the real QCD are often referred to as “holographic QCD” or “AdS/QCD approach”. One of directions in this field is to start from the real QCD and guess a tentative dual higher dimensional weakly coupled field model following the principles of gauge/gravity correspondence. The ensuing phenomenology can be then developed and compared with experimental data and with various theoretical results. Such a bottom-up holographic approach turned out to be unexpectedly successful in many cases. In the given short review, the technical aspects of the bottom-up holographic approach to QCD are explained placing the main emphasis on the soft wall model.

  18. Charmed bottom baryon spectroscopy from lattice QCD

    SciTech Connect

    Brown, Zachary S.; Detmold, William; Meinel, Stefan; Orginos, Kostas

    2014-11-19

    In this study, we calculate the masses of baryons containing one, two, or three heavy quarks using lattice QCD. We consider all possible combinations of charm and bottom quarks, and compute a total of 36 different states with JP = 1/2+ and JP = 3/2+. We use domain-wall fermions for the up, down, and strange quarks, a relativistic heavy-quark action for the charm quarks, and nonrelativistic QCD for the bottom quarks. Our analysis includes results from two different lattice spacings and seven different pion masses. We perform extrapolations of the baryon masses to the continuum limit and to the physical pion mass using SU(4|2) heavy-hadron chiral perturbation theory including 1/mQ and finite-volume effects. For the 14 singly heavy baryons that have already been observed, our results agree with the experimental values within the uncertainties. We compare our predictions for the hitherto unobserved states with other lattice calculations and quark-model studies.

  19. Estimates of bottom roughness length and bottom shear stress in South San Francisco Bay, California

    USGS Publications Warehouse

    Cheng, R.T.; Ling, C.-H.; Gartner, J.W.; Wang, P.-F.

    1999-01-01

    A field investigation of the hydrodynamics and the resuspension and transport of participate matter in a bottom boundary layer was carried out in South San Francisco Bay (South Bay), California, during March-April 1995. Using broadband acoustic Doppler current profilers, detailed measurements of turbulent mean velocity distribution within 1.5 m above bed have been obtained. A global method of data analysis was used for estimating bottom roughness length zo and bottom shear stress (or friction velocities u*). Field data have been examined by dividing the time series of velocity profiles into 24-hour periods and independently analyzing the velocity profile time series by flooding and ebbing periods. The global method of solution gives consistent properties of bottom roughness length zo and bottom shear stress values (or friction velocities u*) in South Bay. Estimated mean values of zo and u* for flooding and ebbing cycles are different. The differences in mean zo and u* are shown to be caused by tidal current flood-ebb inequality, rather than the flooding or ebbing of tidal currents. The bed shear stress correlates well with a reference velocity; the slope of the correlation defines a drag coefficient. Forty-three days of field data in South Bay show two regimes of zo (and drag coefficient) as a function of a reference velocity. When the mean velocity is >25-30 cm s-1, the ln zo (and thus the drag coefficient) is inversely proportional to the reference velocity. The cause for the reduction of roughness length is hypothesized as sediment erosion due to intensifying tidal currents thereby reducing bed roughness. When the mean velocity is <25-30 cm s-1, the correlation between zo and the reference velocity is less clear. A plausible explanation of scattered values of zo under this condition may be sediment deposition. Measured sediment data were inadequate to support this hypothesis, but the proposed hypothesis warrants further field investigation.

  20. Conductivity Probe after Trench-Bottom Placement

    NASA Technical Reports Server (NTRS)

    2008-01-01

    Needles of the thermal and conductivity probe on NASA's Phoenix Mars Lander were positioned into the bottom of a trench called 'Upper Cupboard' during Sol 86 (Aug. 21, 2008), or 86th Martian day after landing. This image of the conductivity probe after it was raised back out of the trench was taken by Phoenix's Robotic Arm Camera. The conductivity probe is at the wrist of the robotic arm's scoop.

    The probe measures how fast heat and electricity move from one needle to an adjacent one through the soil or air between the needles. Conductivity readings can be indicators about water vapor, water ice and liquid water.

    The Phoenix Mission is led by the University of Arizona, Tucson, on behalf of NASA. Project management of the mission is by NASA's Jet Propulsion Laboratory, Pasadena, Calif. Spacecraft development is by Lockheed Martin Space Systems, Denver.

  1. Conductivity Probe after Trench-Bottom Placement

    NASA Technical Reports Server (NTRS)

    2008-01-01

    Needles of the thermal and conductivity probe on NASA's Phoenix Mars Lander were positioned into the bottom of a trench called 'Upper Cupboard' during Sol 86 (Aug. 21, 2008), or 86th Martian day after landing. This image of the conductivity probe after it was raised back out of the trench was taken by Phoenix's Robotic Arm Camera. The conductivity probe is at the wrist of the robotic arm's scoop.

    The probe measures how fast heat and electricity move from one needle to an adjacent one through the soil or air between the needles. Conductivity readings can be indicators about water vapor, water ice and liquid water.

    The Phoenix Mission is led by the University of Arizona, Tucson, on behalf of NASA. Project management of the mission is by NASA's Jet Propulsion Laboratory, Pasadena, Calif. Spacecraft development is by Lockheed Martin Space Systems, Denver.

  2. Station blackout calculations for Peach Bottom

    SciTech Connect

    Hodge, S.A.

    1985-01-01

    A calculational procedure for the Station Blackout Severe Accident Sequence at Browns Ferry Unit One has been repeated with plant-specific application to one of the Peach Bottom Units. The only changes required in code input are with regard to the primary continment concrete, the existence of sprays in the secondary containment, and the size of the refueling bay. Combustible gas mole fractions in the secondary containment of each plant during the accident sequence are determined. It is demonstrated why the current state-of-the-art corium/concrete interaction code is inadequate for application to the study of Severe Accident Sequences in plants with the BWR MK I or MK II containment design.

  3. Peach Bottom test element program. Final report

    SciTech Connect

    Saurwein, J.J.; Holzgraf, J.F.; MIller, C.M.; Myers, B.F.; Wallroth, C.F.

    1982-11-01

    Thirty-three test elements were irradiated in the Peach Bottom high-temperature gas-cooled reactor (HTGR) as part of the testing program for advanced HTGRs. Extensive postirradiation examinations and evaluations of 21 of these irradiation experiments were performed. The test element irradiations were simulated using HTGR design codes and data. Calculated fuel burnups, power profiles, fast neutron fluences, and temperatures were verified via destructive burnup measurements, gamma scanning, and in-pile thermocouple readings corrected for decalibration effects. Analytical techniques were developed to improve the quality of temperature predictions through feedback of nuclear measurements into thermal calculations. Dimensional measurements, pressure burst tests, diametral compression tests, ring-cutting tests, strip-cutting tests, and four-point bend tests were performed to measure residual stress, strain, and strength distributions in H-327 graphite structures irradiated in the test elements.

  4. Discovering bottom squark coannihilation at the ILC

    SciTech Connect

    Belyaev, Alexander; Lastovicka, Tomas; Nomerotski, Andrei; Lastovicka-Medin, Gordana

    2010-02-01

    We study the potential of the international linear collider (ILC) at {radical}(s)=500 GeV to probe new dark matter motivated scenario where the bottom squark (sbottom) is the next-to-lightest supersymmetric particle. For this scenario, which is virtually impossible for the LHC to test, the ILC has a potential to cover a large fraction of the parameter space. The challenge is due to a very low energy of jets, below 20-30 GeV, which pushes the jet clustering and flavor tagging algorithms to their limits. The process of sbottom pair production was studied within the SiD detector concept. We demonstrate that ILC offers a unique opportunity to test the supersymmetry parameter space motivated by the sbottom-neutralino coannihilation scenario in cases when the sbottom production is kinematically accessible. The study was done with the full SiD simulation and reconstruction chain including all standard model and beam backgrounds.

  5. Toxicity of waste gasification bottom ash leachate.

    PubMed

    Sivula, Leena; Oikari, Aimo; Rintala, Jukka

    2012-06-01

    Toxicity of waste gasification bottom ash leachate from landfill lysimeters (112 m(3)) was studied over three years. The leachate of grate incineration bottom ash from a parallel setup was used as reference material. Three aquatic organisms (bioluminescent bacteria, green algae and water flea) were used to study acute toxicity. In addition, an ethoxyresorufin-O-deethylase (EROD) assay was performed with mouse hepatoma cells to indicate the presence of organic contaminants. Concentrations of 14 elements and 15 PAH compounds were determined to characterise leachate. Gasification ash leachate had a high pH (9.2-12.4) and assays with and without pH adjustment to neutral were used. Gasification ash leachate was acutely toxic (EC(50) 0.09-62 vol-%) in all assays except in the algae assay with pH adjustment. The gasification ash toxicity lasted the entire study period and was at maximum after two years of disposal both in water flea (EC(50) 0.09 vol-%) and in algae assays (EC(50) 7.5 vol-%). The grate ash leachate showed decreasing toxicity during the first two years of disposal in water flea and algae assays, which then tapered off. Both in the grate ash and in the gasification ash leachates EROD-activity increased during the first two years of disposal and then tapered off, the highest inductions were observed with the gasification ash leachate. The higher toxicity of the gasification ash leachate was probably related to direct and indirect effects of high pH and to lower levels of TOC and DOC compared to the grate ash leachate. The grate ash leachate toxicity was similar to that previously reported in literature, therefore, confirming that used setup was both comparable and reliable. Copyright © 2012 Elsevier Ltd. All rights reserved.

  6. Active EM Monitoring of Sea-Bottom Geoelectrical Structures in the Areas with the Rough Bathymetry

    NASA Astrophysics Data System (ADS)

    Zhdanov, M. S.

    2007-12-01

    During the recent years, the marine Controlled Source Electromagnetic (MCSEM) method has become widely used for active geophysical surveying of the sea-bottom geological structures in hydrocarbon exploration. A typical MCSEM survey consists of a set of sea-bottom receivers and a moving electrical bipole transmitter. The interpretation of the MCSEM data over the complex 3-D geoelectrical structures is a very challenging problem. This problem becomes even more complicated in the areas with the rough sea-bottom bathymetry, because the relief of a sea bottom makes a profound effect on the EM data observed by the receivers located in the close proximity to the bottom. In this paper I introduce a new approach to interpretation of the MCSEM data in the areas with the rough bathymetry. This approach is based on a new formulation of the integral equation (IE) EM modeling method in the models with inhomogeneous background conductivity. The method is based on the separation of the effects due to excess electric current induced in the inhomogeneous background domain, and those due to the anomalous electric current in the location of the anomalous conductivity, respectively. As a result, we arrive at a system of integral equations which uses the same simple Green's functions for the layered model, as in the original IE formulation. However, the new equations take into account the effect of the variable background conductivity distribution. The developed technique allows us to incorporate the known geological structures and bathymetry effects in the method of iterative EM migration/holographic imaging and inversion. This approach provides us with the ability to pre-compute only once the effect of the known geoelectrical structure (e.g., the bathymetry effect) and keep it unchanged during the entire modeling and migration process. Taking into account that precomputing the bathymetry effect constitutes the most time-consuming part of the EM modeling, this approach allows us to

  7. Ocean bottom pressure variation associated with path variations of the Kuroshio south of Japan

    NASA Astrophysics Data System (ADS)

    Nagano, Akira; Hasegawa, Takuya; Matsumoto, Hiroyuki; Ariyoshi, Keisuke

    2016-04-01

    The Kuroshio south of Japan takes a stable southward meandering path, called the large meander (LM), on interannual to decadal timescales. During the non-LM period, mesoscale disturbances of the Kuroshio path, called small meanders, occasionally occur in the region southeast of Kyushu and propagate eastward. Some of them develop to the LM, possibly associated with deep eddies. In order to reveal the relationship between the development of path disturbances and bottom current (or hydrostatic pressure), we examined variations of ocean bottom pressure obtained by pressure sensors deployed in the region off Shikoku (capes Ashizuri and Muroto). Bottom pressure on the continental slope is found to increase abruptly lagging a few months behind an elevation of sea surface height (SSH) due to the formation of the LM in July 2014. Geopotential distance from the sea surface to 2000 dbar based on hydrographic data at the Affiliated Surveys of the Kuroshio off Cape Ashizuri (ASUKA) line abruptly increases from early to late July. The reduction of density stratification, i.e., the weakened baroclinicity, causes the temporal delay of the increase of bottom pressure relative to the elevation of SSH associated with the formation of the LM.

  8. Bottom morphology in the Song Hau distributary channel, Mekong River Delta, Vietnam

    NASA Astrophysics Data System (ADS)

    Allison, Mead A.; Dallon Weathers, H.; Meselhe, Ehab A.

    2017-09-01

    Field studies in the Song Hau distributary of the Mekong Delta in Vietnam conducted at high (Sept.-Oct 2014) and low (March 2015) Mekong River discharge are utilized to examine channel bottom morphology and links with sediment transport in the system. Multibeam bathymetric mapping surveys over the entire channel complex in the lower 80 km of the distributary channel, and over 12- to 24-h tidal periods at six transect locations in the reach are used to characterize bottom type and change on seasonal and tidal timescales, supplemented by bottom sampling. The results of this study indicate that the largest proportion of channel floor (up to 80% of the total area) is composed of substratum outcrops of relict sediment units deposited during the progradation of the delta in the last 3.5 ka. These take the form of outcrops that are either (1) steep-sided, tabular channel floor, (2) steep-sided sidewall, or (3) relatively flat channel floor. Flatter outcrops of channel floor substratum are identified by the presence of sedimentary furrows (<0.5 m deep) incised into the channel bottom that are exposed at high discharge and oriented along channel and laterally continuous for kilometers. These furrows are persistent in location and extent across tidal cycles and appear to be incised into relict units, sometimes with a thin surficial layer of modern sediment observable in bottom grabs. The extent of substratum exposure, greater than that observed previously in low tidal energy systems like the Mississippi River, may relate both to a relatively low sand supply from the catchment, and/or to an efficient transfer of both sand and mud through this tidally energetic channel. Sand bottom areas forming dunes, comprise about 19% of the channel floor over the study area and are generally less than a few meters thick except on bar extensions of mid-channel islands. Both sandy and substratum areas are mantled by soft muds 0.25-1 m thick during low discharge in the estuarine section of

  9. Trawled megafaunal invertebrate assemblages from bathyal depth of the Mid-Atlantic Ridge (48°-54°N)

    NASA Astrophysics Data System (ADS)

    Alt, Claudia H. S.; Rogacheva, Antonina; Boorman, Benjamin; Alan Hughes, J.; Billett, David S. M.; Gooday, Andrew J.; Jones, Daniel O. B.

    2013-12-01

    We investigated the effects of contrasting surface primary production on the benthic invertebrate megafauna at four sites on the Mid-Atlantic Ridge. The sites, designated NW, NE, SW and SE, were located to the west and east of the Ridge axis and to the north and south of the Charlie-Gibbs Fracture Zone. Benthic megafauna were sampled in 2007 and 2009 with a semi-balloon otter trawl, at a target depth of 2,500 m. The total biomass and density of major taxonomic groups did not differ significantly between sites, despite those to the north being characterised by greater surface productivity than those to the south. However, the density and biomass of individual taxonomic groups, as well as diversity and body size, all showed significant differences between sites. Diversity was highest at the SE, and lowest at the NE site. Most species were larger to the north. Community composition was significantly different between all sites, with the greatest number of unique species found at the SE, and noticeably fewer unique species at the northern sites. There was no clear correlation between the surface productivity and community structure, suggesting complex ecological controls on the communities. It is speculated that, in addition to the energy supply, drivers such as strong currents and sediment characteristics, play an important role in shaping the communities at the different sites. To what extent the ridge acts as a dispersal barrier for benthic invertebrate fauna remains unclear. However, high numbers of species unique to the southern site suggest a limited dispersal between the northern and southern areas.

  10. Spatial overlap of Black-browed albatrosses with longline and trawl fisheries in the Patagonian Shelf during the non-breeding season

    NASA Astrophysics Data System (ADS)

    Copello, Sofía; Seco Pon, Juan Pablo; Favero, Marco

    2014-05-01

    Incidental mortality in fisheries is the main at-sea threat albatrosses are facing nowadays. In this study we used remote sensing techniques to model the degree of spatial overlapping between the Black-browed albatross (Thalassarche melanophris) and Argentine fisheries, assuming this as a proxy of risk for albatrosses. Eleven tags were deployed on albatrosses during the non-breeding seasons 2011 and 2012 in the Patagonian Shelf. Their distribution overlapped to different extents with the two coastal trawl, three offshore trawl and one demersal longline fisheries. The overlap index showed highest values with both coastal fleets, followed by the ice-chilling trawl fleet. These intersections were located in the Argentinean-Uruguayan Common Fishing Zone, in coastal areas of the SE of Buenos Aires province, El Rincón estuary and over the shelf break. The analysis of intersections of focal areas from albatrosses and all fisheries allowed the identification of thirty-four fishing management units (1° by 1° grid within the Argentine EEZ) classified as of medium, high or very high conservation priority. Very high priority units were placed between 35 and 38°S in the external mouth of Rio de la Plata, and between 45 and 47°S in neighboring waters East to the hake fishing closure. Although there were possible biases due to the limited number of tracked birds and the locations where albatrosses were captured and instrumented, the information presented in this study provides a comprehensive picture of important areas of overlapping during winter that could be used by the fishery administration to prioritize conservation actions under limited resource scenarios.

  11. a New Technique Based on Mini-Uas for Estimating Water and Bottom Radiance Contributions in Optically Shallow Waters

    NASA Astrophysics Data System (ADS)

    Montes-Hugo, M. A.; Barrado, C.; Pastor, E.

    2015-08-01

    The mapping of nearshore bathymetry based on spaceborne radiometers is commonly used for QC ocean colour products in littoral waters. However, the accuracy of these estimates is relatively poor with respect to those derived from Lidar systems due in part to the large uncertainties of bottom depth retrievals caused by changes on bottom reflectivity. Here, we present a method based on mini unmanned aerial vehicles (UAS) images for discriminating bottom-reflected and water radiance components by taking advantage of shadows created by different structures sitting on the bottom boundary. Aerial surveys were done with a drone Draganfly X4P during October 1 2013 in optically shallow waters of the Saint Lawrence Estuary, and during low tide. Colour images with a spatial resolution of 3 mm were obtained with an Olympus EPM-1 camera at 10 m height. Preliminary results showed an increase of the relative difference between bright and dark pixels (dP) toward the red wavelengths of the camera's receiver. This is suggesting that dP values can be potentially used as a quantitative proxy of bottom reflectivity after removing artefacts related to Fresnel reflection and bottom adjacency effects.

  12. Velocity and bottom-stress measurements in the bottom boundary layer, outer Norton Sound, Alaska.

    USGS Publications Warehouse

    Cacchione, D.A.; Drake, D.E.; Wiberg, P.

    1982-01-01

    We have used long-term measurements of near-bottom velocities at four heights above the sea floor in Norton Sound, Alaska, to compute hourly values of shear velocity u., roughness and bottom-drag coefficient. Maximum sediment resuspension and transport, predicted for periods when the computed value of u. exceeds a critical level, occur during peak tidal currents associated with spring tides. The fortnightly variation in u. is correlated with a distinct nepheloid layer that intensifies and thickens during spring tides and diminishes and thins during neap tides. The passage of a storm near the end of the experiment caused significantly higher u. values than those found during fair weather.-from Authros

  13. Mid-Frequency Sonar Backscatter Measurements from a Rippled Bottom

    NASA Astrophysics Data System (ADS)

    Lopes, Joseph L.; Lim, Raymond; Commander, Kerry W.

    2004-11-01

    Seafloor ripple reverberation is associated with a peak in the scattering frequency spectrum at a frequency around c/(2λr cos θ), where c is the sound speed in water, λr is the ripple wavelength, and θ is the incident grazing angle. In the vicinity of this peak, perturbation theory predicts the reverberation level to be high enough to be a concern for detection of targets buried under ripple. In order to validate such predictions, an experiment was conducted in the Naval Surface Warfare Center Panama City (NSWC-PC) Facility 383, which is a 13.7-m deep, 110-m long, 80-m wide test pool that has 1.5 m of sand covering the bottom. Backscatter reverberation levels from two bottom configurations were measured using a parametric source that was operated in the 1 to 10 kHz frequency range. One bottom configuration corresponded to a non-rippled, near-flat bottom. The second was a rippled bottom with a Gaussian spectrum centered on a wavelength of 20 cm. The rippled bottom was artificially formed with the aid of a sand scraper. Results showed the reverberation levels were significantly higher in the 3 to 5 kHz frequency range for the rippled bottom than for the non-rippled bottom. The maximum reverberation level for the rippled bottom occurred at 4 kHz, which is consistent with perturbation theory predictions.

  14. Field trail of fiber optic ocean bottom cable

    NASA Astrophysics Data System (ADS)

    Zhang, Wentao; Huang, Wenzhu; Wang, Zhaogang; Luo, Yingbo; Li, Fang

    2015-10-01

    In this paper we present the field test of the fiber optic ocean bottom cable (FOOBC). The FOOBC are several ocean bottom seismic stations connected by optical fiber cables. In the ocean bottom seismic station, there are three orthogonal fiber optic accelerometers and one fiber optic hydrophone. The design of the sensors and stations are introduced. The field demonstration of an ocean bottom seismic station is carried out in Yunnan Province, China. The test results show that the three accelerometers has similar response to the seismic signal with traditional MEMS accelerometers. We believe that the fiber optic seismic cable is promising in the field of oil and gas exploration and earthquake monitoring.

  15. 22. Detail view of approach span, showing bottom chord construction, ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    22. Detail view of approach span, showing bottom chord construction, looking east - India Point Railroad Bridge, Spanning Seekonk River between Providence & East Providence, Providence, Providence County, RI

  16. Stream bottom resistivity tomography to map ground water discharge.

    PubMed

    Nyquist, Jonathan E; Freyer, Paul A; Toran, Laura

    2008-01-01

    This study investigates the effectiveness of direct current electrical resistivity as a tool for assessing ground water/surface water interactions within streams. This research has shown that patterns of ground water discharge can be mapped at the meter scale, which is important for understanding stream water quality and ecosystem function. Underwater electrical resistivity surveys along a 107-m stream section within the Burd Run Watershed in South Central Pennsylvania identified three resistivity layers: a resistive (100 to 400 Omega m) surface layer corresponding to the streambed sediments, a conductive (20 to 100 Omega m) middle layer corresponding to residual clay sediments, and a resistive (100 to 450 Omega m) bottom layer corresponding to the carbonate bedrock. Tile probing to determine the depth to the bedrock and resistivity test box analysis of augered sediment samples confirmed these interpretations of the resistivity data. Ground water seeps occurred where the resistivity data showed that the residual clays were thinnest and bedrock was closest to the streambed. Plotting the difference in resistivity between two surveys, one conducted during low-stage and the other during high-stage stream conditions, showed changes in the conductivity of the pore fluids saturating the sediments. Under high-stream stage conditions, the top layer showed increased resistivity values for sections with surface water infiltration but showed nearly constant resistivity in sections with ground water seeps. This was expressed as difference values less than 50 Omega m in the area of the seeps and greater than 50 Omega m change for the streambed sediments saturated by surface water. Thus, electrical resistivity aided in characterizing ground water discharge zones by detecting variations in subsurface resistivity under high- and low-stream stage conditions as well as mapping subsurface heterogeneities that promote these exchanges.

  17. Analyses of native water, bottom material, and elutriate samples of southern Louisiana waterways, 1977-78

    USGS Publications Warehouse

    Dupuy, Alton J.; Couvillion, Nolan P.

    1979-01-01

    From March 1977 to July 1978 the U.S. Geological Survey in cooperation with the U.S. Army Corps of Engineers conducted a series of elutriate studies to determine water quality in selected reaches of major navigable waterways of southern Louisiana. Sample were collected from the Mississippi River-Gulf Outlet areas; Mississippi River, South Pass; Baptiste Collette Bayou; Tiger Pass area; Baou Long; Bayou Barataria and Barataria Bay Waterway area (gulf section); Bayou Segnette Waterway, Lake Pontchartrain near Tangipahoa River mouth; Bayou Grand Caillou; Bayou la Carpe at Homa; Houma Navigation Canal and Terrebonne Bay; Bayou Boeuf, Bayou Chene, and Baou Black, Atchafalaya River Channel, Atchafalaya Bay; Old River Lock tailbay; Red River below mouth of Black River; Freshwaer Canal; Mermentau River and Lake Arthur Mermentau River outlet; and Calcasieu Ship Channel. The studies were initiated at the request of the U.S. Army Corps of Engineers to evaluate possible environmental effects of proposed dredging activities in those waterways. The U.S. Army Corps of Engineers and U.S. Geological Survey collected 189 samples of native water and 172 samples of bottom (bed) material from 163 different sites. A total of 117 elutriates (Mixtures of native water and bottom material) were prepared. The native water and elutriate samples were analyzed for selected metals, pesticides, nutrients organics, and pysical constituents. Particle-size determinations were made on bottom-material samples. (Kosco-USGS)

  18. Measurements of Direct CP Violating Asymmetries in Charmless Decays of Strange Bottom Mesons and Bottom Baryons

    SciTech Connect

    Aaltonen, T.; Brucken, E.; Devoto, F.; Mehtala, P.; Orava, R.; Alvarez Gonzalez, B.; Casal, B.; Cuevas, J.; Gomez, G.; Palencia, E.; Rodrigo, T.; Ruiz, A.; Scodellaro, L.; Vila, I.; Vilar, R.; Vizan, J.; Amerio, S.; Dorigo, T.; Gresele, A.; Lazzizzera, I.

    2011-05-06

    We report measurements of direct CP--violating asymmetries in charmless decays of neutral bottom hadrons to pairs of charged hadrons with the upgraded Collider Detector at the Fermilab Tevatron. Using a data sample corresponding to 1 fb{sup -1} of integrated luminosity, we obtain the first measurements of direct CP violation in bottom strange mesons, A{sub CP}(B{sub s}{sup 0}{yields}K{sup -}{pi}{sup +})=+0.39{+-}0.15(stat){+-}0.08(syst), and bottom baryons, A{sub CP}({Lambda}{sub b}{sup 0}{yields}p{pi}{sup -})=+0.03{+-}0.17(stat){+-}0.05(syst) and A{sub CP}({Lambda}{sub b}{sup 0}{yields}pK{sup -})=+0.37{+-}0.17(stat){+-}0.03(syst). In addition, we measure CP violation in B{sup 0}{yields}K{sup +}{pi}{sup -} decays with 3.5{sigma} significance, A{sub CP}(B{sup 0}{yields}K{sup +}{pi}{sup -})=-0.086{+-}0.023(stat){+-}0.009(syst), in agreement with the current world average. Measurements of branching fractions of B{sub s}{sup 0}{yields}K{sup +}K{sup -} and B{sup 0}{yields}{pi}{sup +}{pi}{sup -} decays are also updated.

  19. Measurements of direct CP violating asymmetries in charmless decays of strange bottom mesons and bottom baryons.

    PubMed

    Aaltonen, T; Alvarez González, B; Amerio, S; Amidei, D; Anastassov, A; Annovi, A; Antos, J; Apollinari, G; Appel, J A; Apresyan, A; Arisawa, T; Artikov, A; Asaadi, J; Ashmanskas, W; Auerbach, B; Aurisano, A; Azfar, F; Badgett, W; Barbaro-Galtieri, A; Barnes, V E; Barnett, B A; Barria, P; Bartos, P; Bauce, M; Bauer, G; Bedeschi, F; Beecher, D; Behari, S; Bellettini, G; Bellinger, J; Benjamin, D; Beretvas, A; Bhatti, A; Binkley, M; Bisello, D; Bizjak, I; Bland, K R; Blumenfeld, B; Bocci, A; Bodek, A; Bortoletto, D; Boudreau, J; Boveia, A; Brau, B; Brigliadori, L; Brisuda, A; Bromberg, C; Brucken, E; Bucciantonio, M; Budagov, J; Budd, H S; Budd, S; Burkett, K; Busetto, G; Bussey, P; Buzatu, A; Calancha, C; Camarda, S; Campanelli, M; Campbell, M; Canelli, F; Canepa, A; Carls, B; Carlsmith, D; Carosi, R; Carrillo, S; Carron, S; Casal, B; Casarsa, M; Castro, A; Catastini, P; Cauz, D; Cavaliere, V; Cavalli-Sforza, M; Cerri, A; Cerrito, L; Chen, Y C; Chertok, M; Chiarelli, G; Chlachidze, G; Chlebana, F; Cho, K; Chokheli, D; Chou, J P; Chung, W H; Chung, Y S; Ciobanu, C I; Ciocci, M A; Clark, A; Compostella, G; Convery, M E; Conway, J; Corbo, M; Cordelli, M; Cox, C A; Cox, D J; Crescioli, F; Cuenca Almenar, C; Cuevas, J; Culbertson, R; Dagenhart, D; d'Ascenzo, N; Datta, M; de Barbaro, P; De Cecco, S; De Lorenzo, G; Dell'orso, M; Deluca, C; Demortier, L; Deng, J; Deninno, M; Devoto, F; d'Errico, M; Di Canto, A; Di Ruzza, B; Dittmann, J R; D'Onofrio, M; Donati, S; Dong, P; Dorigo, M; Dorigo, T; Ebina, K; Elagin, A; Eppig, A; Erbacher, R; Errede, D; Errede, S; Ershaidat, N; Eusebi, R; Fang, H C; Farrington, S; Feindt, M; Fernandez, J P; Ferrazza, C; Field, R; Flanagan, G; Forrest, R; Frank, M J; Franklin, M; Freeman, J C; Funakoshi, Y; Furic, I; Gallinaro, M; Galyardt, J; Garcia, J E; Garfinkel, A F; Garosi, P; Gerberich, H; Gerchtein, E; Giagu, S; Giakoumopoulou, V; Giannetti, P; Gibson, K; Ginsburg, C M; Giokaris, N; Giromini, P; Giunta, M; Giurgiu, G; Glagolev, V; Glenzinski, D; Gold, M; Goldin, D; Goldschmidt, N; Golossanov, A; Gomez, G; Gomez-Ceballos, G; Goncharov, M; González, O; Gorelov, I; Goshaw, A T; Goulianos, K; Gresele, A; Grinstein, S; Grosso-Pilcher, C; Group, R C; Guimaraes da Costa, J; Gunay-Unalan, Z; Haber, C; Hahn, S R; Halkiadakis, E; Hamaguchi, A; Han, J Y; Happacher, F; Hara, K; Hare, D; Hare, M; Harr, R F; Hatakeyama, K; Hays, C; Heck, M; Heinrich, J; Herndon, M; Hewamanage, S; Hidas, D; Hocker, A; Hopkins, W; Horn, D; Hou, S; Hughes, R E; Hurwitz, M; Husemann, U; Hussain, N; Hussein, M; Huston, J; Introzzi, G; Iori, M; Ivanov, A; James, E; Jang, D; Jayatilaka, B; Jeon, E J; Jha, M K; Jindariani, S; Johnson, W; Jones, M; Joo, K K; Jun, S Y; Junk, T R; Kamon, T; Karchin, P E; Kato, Y; Ketchum, W; Keung, J; Khotilovich, V; Kilminster, B; Kim, D H; Kim, H S; Kim, H W; Kim, J E; Kim, M J; Kim, S B; Kim, S H; Kim, Y K; Kimura, N; Kirby, M; Klimenko, S; Kondo, K; Kong, D J; Konigsberg, J; Kotwal, A V; Kreps, M; Kroll, J; Krop, D; Krumnack, N; Kruse, M; Krutelyov, V; Kuhr, T; Kurata, M; Kwang, S; Laasanen, A T; Lami, S; Lammel, S; Lancaster, M; Lander, R L; Lannon, K; Lath, A; Latino, G; Lazzizzera, I; Lecompte, T; Lee, E; Lee, H S; Lee, J S; Lee, S W; Leo, S; Leone, S; Lewis, J D; Lin, C-J; Linacre, J; Lindgren, M; Lipeles, E; Lister, A; Litvintsev, D O; Liu, C; Liu, Q; Liu, T; Lockwitz, S; Lockyer, N S; Loginov, A; Lucchesi, D; Lueck, J; Lujan, P; Lukens, P; Lungu, G; Lys, J; Lysak, R; Madrak, R; Maeshima, K; Makhoul, K; Maksimovic, P; Malik, S; Manca, G; Manousakis-Katsikakis, A; Margaroli, F; Marino, C; Martínez, M; Martínez-Ballarín, R; Mastrandrea, P; Mathis, M; Mattson, M E; Mazzanti, P; McFarland, K S; McIntyre, P; McNulty, R; Mehta, A; Mehtala, P; Menzione, A; Mesropian, C; Miao, T; Mietlicki, D; Mitra, A; Miyake, H; Moed, S; Moggi, N; Mondragon, M N; Moon, C S; Moore, R; Morello, M J; Morlock, J; Movilla Fernandez, P; Mukherjee, A; Muller, Th; Murat, P; Mussini, M; Nachtman, J; Nagai, Y; Naganoma, J; Nakano, I; Napier, A; Nett, J; Neu, C; Neubauer, M S; Nielsen, J; Nodulman, L; Norniella, O; Nurse, E; Oakes, L; Oh, S H; Oh, Y D; Oksuzian, I; Okusawa, T; Orava, R; Ortolan, L; Pagan Griso, S; Pagliarone, C; Palencia, E; Papadimitriou, V; Paramonov, A A; Patrick, J; Pauletta, G; Paulini, M; Paus, C; Pellett, D E; Penzo, A; Phillips, T J; Piacentino, G; Pianori, E; Pilot, J; Pitts, K; Plager, C; Pondrom, L; Potamianos, K; Poukhov, O; Prokoshin, F; Pronko, A; Ptohos, F; Pueschel, E; Punzi, G; Pursley, J; Rahaman, A; Ramakrishnan, V; Ranjan, N; Redondo, I; Renton, P; Rescigno, M; Rimondi, F; Ristori, L; Robson, A; Rodrigo, T; Rodriguez, T; Rogers, E; Rolli, S; Roser, R; Rossi, M; Rubbo, F; Ruffini, F; Ruiz, A; Russ, J; Rusu, V; Safonov, A; Sakumoto, W K; Sakurai, Y; Santi, L; Sartori, L; Sato, K; Saveliev, V; Savoy-Navarro, A; Schlabach, P; Schmidt, A; Schmidt, E E; Schmidt, M P; Schmitt, M; Schwarz, T; Scodellaro, L; Scribano, A; Scuri, F; Sedov, A; Seidel, S; Seiya, Y; Semenov, A; Sforza, F; Sfyrla, A; Shalhout, S Z; Shears, T; Shepard, P F; Shimojima, M; Shiraishi, S; Shochet, M; Shreyber, I; Simonenko, A; Sinervo, P; Sissakian, A; Sliwa, K; Smith, J R; Snider, F D; Soha, A; Somalwar, S; Sorin, V; Squillacioti, P; Stancari, M; Stanitzki, M; St Denis, R; Stelzer, B; Stelzer-Chilton, O; Stentz, D; Strologas, J; Strycker, G L; Sudo, Y; Sukhanov, A; Suslov, I; Takemasa, K; Takeuchi, Y; Tang, J; Tecchio, M; Teng, P K; Thom, J; Thome, J; Thompson, G A; Thomson, E; Ttito-Guzmán, P; Tkaczyk, S; Toback, D; Tokar, S; Tollefson, K; Tomura, T; Tonelli, D; Torre, S; Torretta, D; Totaro, P; Trovato, M; Tu, Y; Ukegawa, F; Uozumi, S; Varganov, A; Vázquez, F; Velev, G; Vellidis, C; Vidal, M; Vila, I; Vilar, R; Vizán, J; Vogel, M; Volpi, G; Wagner, P; Wagner, R L; Wakisaka, T; Wallny, R; Wang, S M; Warburton, A; Waters, D; Weinberger, M; Wester, W C; Whitehouse, B; Whiteson, D; Wicklund, A B; Wicklund, E; Wilbur, S; Wick, F; Williams, H H; Wilson, J S; Wilson, P; Winer, B L; Wittich, P; Wolbers, S; Wolfe, H; Wright, T; Wu, X; Wu, Z; Yamamoto, K; Yamaoka, J; Yang, T; Yang, U K; Yang, Y C; Yao, W-M; Yeh, G P; Yi, K; Yoh, J; Yorita, K; Yoshida, T; Yu, G B; Yu, I; Yu, S S; Yun, J C; Zanetti, A; Zeng, Y; Zucchelli, S

    2011-05-06

    We report measurements of direct CP-violating asymmetries in charmless decays of neutral bottom hadrons to pairs of charged hadrons with the upgraded Collider Detector at the Fermilab Tevatron. Using a data sample corresponding to 1 fb(-1) of integrated luminosity, we obtain the first measurements of direct CP violation in bottom strange mesons, A(CP)(B(s)(0)→K(-)π(+))=+0.39±0.15(stat)±0.08(syst), and bottom baryons, A(CP)(Λ(b)(0)→pπ(-))=+0.03±0.17(stat)±0.05(syst) and A(CP)(Λ(b)(0)→pK(-))=+0.37±0.17(stat)±0.03(syst). In addition, we measure CP violation in B(0)→K(+)π(-) decays with 3.5σ significance, A(CP)(B(0)→K(+)π(-))=-0.086±0.023(stat)±0.009(syst), in agreement with the current world average. Measurements of branching fractions of B(s)(0)→K(+)K(-) and B(0)→π(+)π(-) decays are also updated.

  20. Busy at the Bottom of 'Endurance Crater'

    NASA Technical Reports Server (NTRS)

    2004-01-01

    [figure removed for brevity, see original site] [figure removed for brevity, see original site] Figure 1Figure 2

    This mosaic from the navigation camera aboard NASA's Mars Exploration Rover Opportunity was compiled from images taken on the rover's 193rd and 194th sol on Mars (August 9 and 10, 2004). The rover's current work area near the bottom of 'Endurance Crater' is featured in this image. In coming sols, Opportunity will make its way toward the interesting rock, 'Wopmay,' located on the far right of this image, on the crater's inner slopes just beneath 'Burns Cliff.' Scientists say the rock's unusual texture is unlike any others observed so far at Meridiani Planum. Wopmay measures approximately 1 meter (3.3 feet) across. This image is presented in cylindrical projection, with geometric and radiometric seam correction.

    Figure 1 is the left-eye view of a stereo pair and Figure 2 is the right-eye view of a stereo pair.

  1. Bottom-up assembly of metallic germanium

    PubMed Central

    Scappucci, Giordano; Klesse, Wolfgang M.; Yeoh, LaReine A.; Carter, Damien J.; Warschkow, Oliver; Marks, Nigel A.; Jaeger, David L.; Capellini, Giovanni; Simmons, Michelle Y.; Hamilton, Alexander R.

    2015-01-01

    Extending chip performance beyond current limits of miniaturisation requires new materials and functionalities that integrate well with the silicon platform. Germanium fits these requirements and has been proposed as a high-mobility channel material, a light emitting medium in silicon-integrated lasers, and a plasmonic conductor for bio-sensing. Common to these diverse applications is the need for homogeneous, high electron densities in three-dimensions (3D). Here we use a bottom-up approach to demonstrate the 3D assembly of atomically sharp doping profiles in germanium by a repeated stacking of two-dimensional (2D) high-density phosphorus layers. This produces high-density (1019 to 1020 cm−3) low-resistivity (10−4Ω · cm) metallic germanium of precisely defined thickness, beyond the capabilities of diffusion-based doping technologies. We demonstrate that free electrons from distinct 2D dopant layers coalesce into a homogeneous 3D conductor using anisotropic quantum interference measurements, atom probe tomography, and density functional theory. PMID:26256239

  2. Bottom sediments of Saginaw Bay, Michigan

    USGS Publications Warehouse

    Wood, Leonard E.

    1964-01-01

    Saginaw Bay is a southwest extension of Lake Huron on the east shore of the Southern Peninsula of Michigan. It is a shallow-water derivative of the Pleistocene Lake Saginaw. Sixty-one bottom samples were collected on a semigrid pattern and analyzed physically. Findings were treated statistically. Sediments range in size from large pebbles to clay. Medium- to fine-grained clear quartz sand is common to all parts of the bay. Currents and wave action are primarily responsible for both median diameter and sorting distribution patterns. Only a very general correlation can be established between depth and median diameter. Heavy minerals occur in abundance locally and show an affinity to shallow-water areas subject to prevailing currents. Shape also locally determines heavy mineral concentrations. Only general conclusions can be established from roundness and sphericity and acid-soluble content. Increased organic content is correlative with quiet water environments. The shallow-water, heterogeneous nature of Saginaw Bay is not conducive to the recognition of sedimentary criteria suitable for correlations in other than a local environment.

  3. Bottoms Up. [report on the Defense Department

    SciTech Connect

    Isaacs, J.

    1993-11-01

    The [open quotes]Bottoms Up Review[close quotes] was the Pentagon's ongoing reevaluation of the dangers faced by the United States and the forces needed to deal with those dangers. Its purpose was [open quotes]to define the strategy, force structure, modernization programs, industrial base, and infrastucture needed to meet new dangers and seize new opportunities.[close quotes] The report was released in early September. Washington's reaction to the review (generally silence) and the review's major shortcomings are discussed is this article. The central shortfall of the review is the disconnection between the latest military plan and the security threats faced by the United States. As an example of the disconnection, the Pentagon's fiscal 1994 budget request allots less than one percent of the $263 billion budget request to destroy nuclear weapons in the former Soviet Union, to fund peacekeeping operations, to support economic conversion, and to counter proliferation, although these problems are among those slated as among the most important when listed in the review.

  4. Bottom-up assembly of metallic germanium.

    PubMed

    Scappucci, Giordano; Klesse, Wolfgang M; Yeoh, LaReine A; Carter, Damien J; Warschkow, Oliver; Marks, Nigel A; Jaeger, David L; Capellini, Giovanni; Simmons, Michelle Y; Hamilton, Alexander R

    2015-08-10

    Extending chip performance beyond current limits of miniaturisation requires new materials and functionalities that integrate well with the silicon platform. Germanium fits these requirements and has been proposed as a high-mobility channel material, a light emitting medium in silicon-integrated lasers, and a plasmonic conductor for bio-sensing. Common to these diverse applications is the need for homogeneous, high electron densities in three-dimensions (3D). Here we use a bottom-up approach to demonstrate the 3D assembly of atomically sharp doping profiles in germanium by a repeated stacking of two-dimensional (2D) high-density phosphorus layers. This produces high-density (10(19) to 10(20) cm(-3)) low-resistivity (10(-4)Ω · cm) metallic germanium of precisely defined thickness, beyond the capabilities of diffusion-based doping technologies. We demonstrate that free electrons from distinct 2D dopant layers coalesce into a homogeneous 3D conductor using anisotropic quantum interference measurements, atom probe tomography, and density functional theory.

  5. Hadron Physics at the Charm and Bottom Thresholds and Other Novel QCD Physics Topics at the NICA Accelerator Facility

    SciTech Connect

    Brodsky, Stanley J.; /SLAC

    2012-06-20

    The NICA collider project at the Joint Institute for Nuclear Research in Dubna will have the capability of colliding protons, polarized deuterons, and nuclei at an effective nucleon-nucleon center-of mass energy in the range {radical}s{sub NN} = 4 to 11 GeV. I briefly survey a number of novel hadron physics processes which can be investigated at the NICA collider. The topics include the formation of exotic heavy quark resonances near the charm and bottom thresholds, intrinsic strangeness, charm, and bottom phenomena, hidden-color degrees of freedom in nuclei, color transparency, single-spin asymmetries, the RHIC baryon anomaly, and non-universal antishadowing.

  6. Impact of the Charleston Ocean Dredged Material Disposal Site on nearby hard bottom reef habitats.

    PubMed

    Crowe, Stacie E; Gayes, Paul T; Viso, Richard F; Bergquist, Derk C; Jutte, Pamela C; Van Dolah, Robert F

    2010-05-01

    The deepening of shipping and entrance channels in Charleston Harbor (South Carolina, USA) was completed in April 2002 and placed an estimated 22 million cubic yards (mcy) of material in the offshore Charleston Ocean Dredged Material Disposal Site (ODMDS). To determine if sediments dispersed from the ODMDS were negatively affecting invertebrate and/or finfish communities at hard bottom reef areas around the disposal area, six study sites were established: three close to and downdrift of the ODMDS and three upcurrent and farther from the ODMDS. These sites were monitored biannually from 2000 to 2005 using diver surveys and annually using simultaneous underwater video tows and detailed sidescan-sonar. In general, the sediment characteristics of downdrift sites and reference sites changed similarly over time. Overall, the hard bottom reef areas and their associated communities showed little evidence of degradation resulting from the movement of sediments from the Charleston ODMDS during the study period.

  7. Validation of soft bottom benthic habitats identified by single-beam acoustics.

    PubMed

    Freitas, R; Sampaio, L; Oliveira, J; Rodrigues, A M; Quintino, V

    2006-01-01

    Acoustic diversity charts were produced for a Portuguese soft bottom mid-shelf area, depth from 30 to 90 m, using a single-beam echo sounder coupled to the acoustic systems QTC VIEW Series IV and V. A similar acoustic pattern was identified by both systems, which, after ground-truth interpretation based in available sediment and biological data, established a preliminary spatial distribution model of the benthic habitats in this coastal area. However, some of the acoustic areas were interpreted using one or very few sediment and benthic samples. A specific validation survey was conducted a posteriori, in which the positioning of the sediment and benthic community sampling sites was based on the acoustic diversity previously identified. The results clearly confirm the benthic habitats distribution model suggested by the acoustic method, indicating a high potential for the use of such approach in the identification and mapping of large-scale soft bottom coastal shelf habitat diversity.

  8. Quality of bottom material and elutriates in the lower Willamette River, Portland Harbor, Oregon

    USGS Publications Warehouse

    Fuhrer, Gregory J.

    1989-01-01

    In October 1983 the U.S. Geological Survey, in cooperation with the U.S. Army Corp of Engineers, collected bottom-material and water samples from Portland Harbor, Oregon to determine concentrations of trace metals and organic compounds in elutriate-test filtrate and bottom material. Of the trace metals examined in bottom material, concentrations of cadmium slightly exceed those of local rocks, whereas lead and zinc exceedance is substantially larger. Of the organochlorine compounds examined in bottom material chlordane, DDD, DDE, DDT, dieldrin, and polychlorinated biphenyls (PCB's) were detected and quantified in at least 30% of the samples tested. A large DDT concentration (2,700 microgram/kilogram) near Doane Lake outlet is indicative of recent contamination. Polychlorinated biphenyls are ubiquitous in bottom sediments; median concentrations are nearly 65 micrograms/kilogram and as large as 550 microgram/kilogram. PCB loading to the Columbia River from Willamette River suspended sediment has been estimated to be 72 kilograms/year, nearly five times the PCB dredge load of 15 kilogram/year. The acid and base-neutral extractable di-n-butyl phthalate and bis (2-ethylhexyl)phthalate occur in sediments of Terminal No. 2 in concentrations as large as 1,965 and 2,200 micrograms/kilogram, respectively. Of the trace metals examined in both standard and oxic elutriate-test filtrate, only copper concentration in an oxic elutriate-test filtrate (19 micrograms/L) exceeded the water quality criteria (5.7 micrograms/L). (USGS)

  9. Ocean bottom seismometer: design and test of a measurement system for marine seismology.

    PubMed

    Mànuel, Antoni; Roset, Xavier; Del Rio, Joaquin; Toma, Daniel Mihai; Carreras, Normandino; Panahi, Shahram Shariat; Garcia-Benadí, A; Owen, Tim; Cadena, Javier

    2012-01-01

    The Ocean Bottom Seismometer (OBS) is a key instrument for the geophysical study of sea sub-bottom layers. At present, more reliable autonomous instruments capable of recording underwater for long periods of time and therefore handling large data storage are needed. This paper presents a new Ocean Bottom Seismometer designed to be used in long duration seismic surveys. Power consumption and noise level of the acquisition system are the key points to optimize the autonomy and the data quality. To achieve our goals, a new low power data logger with high resolution and Signal-to-Noise Ratio (SNR) based on Compact Flash memory card is designed to enable continuous data acquisition. The equipment represents the achievement of joint work from different scientific and technological disciplines as electronics, mechanics, acoustics, communications, information technology, marine geophysics, etc. This easy to handle and sophisticated equipment allows the recording of useful controlled source and passive seismic data, as well as other time varying data, with multiple applications in marine environment research. We have been working on a series of prototypes for ten years to improve many of the aspects that make the equipment easy to handle and useful to work in deep-water areas. Ocean Bottom Seismometers (OBS) have received growing attention from the geoscience community during the last forty years. OBS sensors recording motion of the ocean floor hold key information in order to study offshore seismicity and to explore the Earth's crust. In a seismic survey, a series of OBSs are placed on the seabed of the area under study, where they record either natural seismic activity or acoustic signals generated by compressed air-guns on the ocean surface. The resulting data sets are subsequently used to model both the earthquake locations and the crustal structure.

  10. Ocean Bottom Seismometer: Design and Test of a Measurement System for Marine Seismology

    PubMed Central

    Mànuel, Antoni; Roset, Xavier; Del Rio, Joaquin; Toma, Daniel Mihai; Carreras, Normandino; Panahi, Shahram Shariat; Garcia-Benadí, A.; Owen, Tim; Cadena, Javier

    2012-01-01

    The Ocean Bottom Seismometer (OBS) is a key instrument for the geophysical study of sea sub-bottom layers. At present, more reliable autonomous instruments capable of recording underwater for long periods of time and therefore handling large data storage are needed. This paper presents a new Ocean Bottom Seismometer designed to be used in long duration seismic surveys. Power consumption and noise level of the acquisition system are the key points to optimize the autonomy and the data quality. To achieve our goals, a new low power data logger with high resolution and Signal–to-Noise Ratio (SNR) based on Compact Flash memory card is designed to enable continuous data acquisition. The equipment represents the achievement of joint work from different scientific and technological disciplines as electronics, mechanics, acoustics, communications, information technology, marine geophysics, etc. This easy to handle and sophisticated equipment allows the recording of useful controlled source and passive seismic data, as well as other time varying data, with multiple applications in marine environment research. We have been working on a series of prototypes for ten years to improve many of the aspects that make the equipment easy to handle and useful to work in deep-water areas. Ocean Bottom Seismometers (OBS) have received growing attention from the geoscience community during the last forty years. OBS sensors recording motion of the ocean floor hold key information in order to study offshore seismicity and to explore the Earth’s crust. In a seismic survey, a series of OBSs are placed on the seabed of the area under study, where they record either natural seismic activity or acoustic signals generated by compressed air-guns on the ocean surface. The resulting data sets are subsequently used to model both the earthquake locations and the crustal structure. PMID:22737032

  11. Implementation of the new hydrographic technologies for bottom topography and seafloor gas venting investigations in the russian northern seas

    NASA Astrophysics Data System (ADS)

    Koloskov, Evgenii

    2017-04-01

    -hydrates survey is stated. The attention is paid to the implementation of the parametric sub bottom profilers - the low frequency sonar for the sea bottom vertical section investigation. The ability for the integrated presentation of the multibeam bathymetry and vertical curtains in the 3D environment are discussed. As an example of the modern swath survey results achieved with Kongsberg EM2040CD MB and hydrographic information technology QINSy/ Fledermause, are discussed and presented. This survey was performed for the RosNeft company in the Kara sea. Recommendations for the implementation of the multi beam echo sounder and parametric sub bottom profiler for the combined hydrographic and submarine gas-hydrates survey in the Russian northern seas are delivered.The gas-hydrate survey guidelines using MB and QINSy/Fledermause software are provided. The hydrographic software tools used to process and analyze the bathymetry can create the seafloor DTM with the high degree of resolution and provide 3D visualization.These new possibilities provide such realistic view of the sea bottom relief and environment that can be characterized as the marine landscapes. Thus it became possible to investigate the relief morphological peculiarities and obtain the information about the relief genesis. This opens the new opportunities for using the acoustic techniques for varies types of marine activity including the bottom environmental study. The appearance of the bottom thermokarst activity derived from the high resolution DTM generated from the real time MB data is presented. The bottom thermokarst provides the potential threat for underwater pipelines and other submarine communications. The arctic bottom relief peculiarities are also covered including grounded hummock traces and dome-shaped elevations. The investigation of such bottom land forms has become possible recently as the result of implementing the wide swath survey methods. Such unique relief features are in general related to seabed

  12. 45. (Credit JTL) View looking up from bottom of #3 ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    45. (Credit JTL) View looking up from bottom of #3 low service pump pit showing frame of Worthington pump on right, water delivery pipe on left and top of 1943 6 mgd electric pump at bottom. - McNeil Street Pumping Station, McNeil Street & Cross Bayou, Shreveport, Caddo Parish, LA

  13. 21. UNDERSIDE OF EPPELSHEIMER BOTTOM GRIP: Photocopy of 1905 photograph ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    21. UNDERSIDE OF EPPELSHEIMER BOTTOM GRIP: Photocopy of 1905 photograph showing the underside of an Eppelsheimer bottom grip. The position of the cable between the jaws is clearly evident. Photograph taken at the Washington and Mason Street powerhouse. - San Francisco Cable Railway, Washington & Mason Streets, San Francisco, San Francisco County, CA

  14. Installation of new bottom in existing above ground storage tank

    SciTech Connect

    Stapleton, W.E.

    1995-12-31

    New bottom installation in existing aboveground storage tanks is a simple process when the correct procedures are followed in preparation for the bottom replacement. An in-depth inspection must be conducted to determine the exact modifications required during the installation of the new bottom, internal decisions made as to type of construction required, and a detailed scope of work prepared to insure all aspects of the tank bottom replacement are detailed. Determining the scope of work requires an in-depth tank inspection, making decisions on the type of bottom to be installed, tank modifications required, tank appurtenance modifications and relocation, whether leak detection, cathodic protection, and secondary containment are to be installed and a decision on whether the old tank bottom will remain in place or be removed. Upon completion of the new bottom installation, a final check to ensure all modifications were performed per API-650 and API-653 and all non-destructive testing procedures were conducted, will insure a safe, leak free bottom providing many years of maintenance free service.

  15. 6. Aerial view northwest, State Route 100 bottom left and ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    6. Aerial view northwest, State Route 100 bottom left and center, Winterthur Train Station center left, Winterthur Farms dairy barns upper center , duck pond and reservoir center, State Route 92 center right, and Brandywine Creek State Park bottom right. - Winterthur Farms, Intersection State Routes 92 & 100, Intersection State Routes 92 & 100, Winterthur, New Castle County, DE

  16. 49 CFR 178.255-5 - Bottom discharge outlets.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... outlets prohibited, except on tanks used for shipments of sludge acid and alkaline corrosive liquids. (b) If installed, bottom outlets or bottom washout chambers shall be of metal not subject to rapid deterioration by the lading, and each shall be provided with a valve or plug at its upper end and liquid-tight...

  17. 49 CFR 178.255-5 - Bottom discharge outlets.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ..., except on tanks used for shipments of sludge acid and alkaline corrosive liquids. (b) If installed, bottom outlets or bottom washout chambers shall be of metal not subject to rapid deterioration by the lading, and each shall be provided with a valve or plug at its upper end and liquid-tight closure at it...

  18. Where's the "Up" in Bottom-Up Reform?

    ERIC Educational Resources Information Center

    Honig, Meredith I.

    2004-01-01

    Bottom-up reform as a policy strategy for decades has faltered in implementation. This article starts from the premise that these disappointing results stem from researchers' and practitioners' almost exclusive focus on implementation in schools or on what some call "the bottom" of hierarchical education systems but not shifts in policy…

  19. Bottom-up Attention Orienting in Young Children with Autism

    ERIC Educational Resources Information Center

    Amso, Dima; Haas, Sara; Tenenbaum, Elena; Markant, Julie; Sheinkopf, Stephen J.

    2014-01-01

    We examined the impact of simultaneous bottom-up visual influences and meaningful social stimuli on attention orienting in young children with autism spectrum disorders (ASDs). Relative to typically-developing age and sex matched participants, children with ASDs were more influenced by bottom-up visual scene information regardless of whether…

  20. Postcolonial Appalachia: Bhabha, Bakhtin, and Diane Gilliam Fisher's "Kettle Bottom"

    ERIC Educational Resources Information Center

    Stevenson, Sheryl

    2006-01-01

    Diane Gilliam Fisher's 2004 award-winning book of poems, "Kettle Bottom," offers students a revealing vantage point for seeing Appalachian regional culture in a postcolonial context. An artful and accessible poetic sequence that was selected as the 2005 summer reading for entering students at Smith College, "Kettle Bottom"…

  1. 5. Aerial view west, Adams Dam Road bottom center, State ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    5. Aerial view west, Adams Dam Road bottom center, State Route 100 center, duck pond and reservoir center, State Route 100 center right, State Route 92 below center right, Brandywine Creek State Park center bottom. - Winterthur Farms, Intersection State Routes 92 & 100, Intersection State Routes 92 & 100, Winterthur, New Castle County, DE

  2. 2. Aerial view northeast, State Route 92 bottom left and ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    2. Aerial view northeast, State Route 92 bottom left and State Route 100 center, Brandywine Creek State Park center right, duck pond and reservoir center bottom. - Winterthur Farms, Intersection State Routes 92 & 100, Intersection State Routes 92 & 100, Winterthur, New Castle County, DE

  3. Bottom-up Attention Orienting in Young Children with Autism

    ERIC Educational Resources Information Center

    Amso, Dima; Haas, Sara; Tenenbaum, Elena; Markant, Julie; Sheinkopf, Stephen J.

    2014-01-01

    We examined the impact of simultaneous bottom-up visual influences and meaningful social stimuli on attention orienting in young children with autism spectrum disorders (ASDs). Relative to typically-developing age and sex matched participants, children with ASDs were more influenced by bottom-up visual scene information regardless of whether…

  4. 49 CFR 179.220-18 - Bottom outlets.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... may be equipped with a bottom outlet of approved design and an opening provided in the outer shell of... at or below the “V” groove, or its equivalent. (8) The valve must have no wings or stem projection... repairs, including grinding. (b) Inner container may be equipped with bottom washout of approved...

  5. 8. Comparison of construction of bottom and top chords and ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    8. Comparison of construction of bottom and top chords and pin connections, bottom chord second panel point, top chords showing third panel point. - Bridge No. 2.4, Spanning Boiling Fork Creek at Railroad Milepost JC-2.4, Decherd, Franklin County, TN

  6. 49 CFR 179.220-18 - Bottom outlets.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... suitable locking arrangement to insure positive closure during transportation. (4) Valve outlet nozzle and... connections, the bottom of the main portion of the outlet nozzle or valve body, or some fixed attachment... having minimum 1-inch threaded pipe plug. (6) If outlet nozzle and its closure extends below the bottom...

  7. 49 CFR 179.220-18 - Bottom outlets.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... arrangement to insure positive closure during transportation. (4) Valve outlet nozzle and valve body must be... bottom of the main portion of the outlet nozzle or valve body, or some fixed attachment thereto, must be... threaded pipe plug. (6) If outlet nozzle and its closure extends below the bottom of the outer shell, a V...

  8. 49 CFR 179.220-18 - Bottom outlets.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... arrangement to insure positive closure during transportation. (4) Valve outlet nozzle and valve body must be... bottom of the main portion of the outlet nozzle or valve body, or some fixed attachment thereto, must be... threaded pipe plug. (6) If outlet nozzle and its closure extends below the bottom of the outer shell, a V...

  9. 49 CFR 179.200-17 - Bottom outlets.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... least 3/8-inch chain, or its equivalent, except that the bottom outlet closure plugs may be attached by... attachment. In no case shall the breakage groove or equivalent extend below the bottom flange of the center... exterior valves may be steam jacketed, in which case the breakage groove or its equivalent must be below...

  10. A survey of surveys

    SciTech Connect

    Kent, S.M.

    1994-11-01

    A new era for the field of Galactic structure is about to be opened with the advent of wide-area digital sky surveys. In this article, the author reviews the status and prospects for research for 3 new ground-based surveys: the Sloan Digital Sky Survey (SDSS), the Deep Near-Infrared Survey of the Southern Sky (DENIS) and the Two Micron AU Sky Survey (2MASS). These surveys will permit detailed studies of Galactic structure and stellar populations in the Galaxy with unprecedented detail. Extracting the information, however, will be challenging.

  11. Combining bottom-up and top-down attentional influences

    NASA Astrophysics Data System (ADS)

    Navalpakkam, Vidhya; Itti, Laurent

    2006-02-01

    Visual attention to salient and relevant scene regions is crucial for an animal's survival in the natural world. It is guided by a complex interplay of at least two factors: image-driven, bottom-up salience [1] and knowledge-driven, top-down guidance [2, 3]. For instance, a ripe red fruit among green leaves captures visual attention due to its bottom-up salience, while a non-salient camou aged predator is detected through top-down guidance to known predator locations and features. Although both bottom-up and top-down factors are important for guiding visual attention, most existing models and theories are either purely top-down [4] or bottom-up [5, 6]. Here, we present a combined model of bottom-up and top-down visual attention.

  12. Southern Ocean bottom water characteristics in CMIP5 models

    NASA Astrophysics Data System (ADS)

    Heuzé, CéLine; Heywood, Karen J.; Stevens, David P.; Ridley, Jeff K.

    2013-04-01

    Southern Ocean deep water properties and formation processes in climate models are indicative of their capability to simulate future climate, heat and carbon uptake, and sea level rise. Southern Ocean temperature and density averaged over 1986-2005 from 15 CMIP5 (Coupled Model Intercomparison Project Phase 5) climate models are compared with an observed climatology, focusing on bottom water. Bottom properties are reasonably accurate for half the models. Ten models create dense water on the Antarctic shelf, but it mixes with lighter water and is not exported as bottom water as in reality. Instead, most models create deep water by open ocean deep convection, a process occurring rarely in reality. Models with extensive deep convection are those with strong seasonality in sea ice. Optimum bottom properties occur in models with deep convection in the Weddell and Ross Gyres. Bottom Water formation processes are poorly represented in ocean models and are a key challenge for improving climate predictions.

  13. Cooperation between scientists, NGOs and industry in support of sustainable fisheries: the South African hake Merluccius spp. trawl fishery experience.

    PubMed

    Field, J G; Attwood, C G; Jarre, A; Sink, K; Atkinson, L J; Petersen, S

    2013-10-01

    This paper examines the increasingly close interaction between natural and social scientists, non-governmental organizations (NGO) and industry, in pursuit of responsible ecosystem-based management of fisheries. South Africa has committed to implementing an ecosystem approach to fisheries management. Management advice stems from multi-stakeholder representation on government-led scientific and management working groups. In the hake Merluccius capensis and Merluccius paradoxus fishery, the primary management measure is an annual total allowable catch (TAC), the level of which is calculated using a management procedure (MP) that is revised approximately every 4 years. Revision of the MP is a consultative process involving most stakeholders, and is based on simulation modelling of projected probable scenarios of resource and fishery dynamics under various management options. NGOs, such as the Worldwide Fund for Nature in South Africa (WWF-SA), have played an important role in influencing consumers, the fishing industry and government to develop responsible fishing practices that minimize damage to marine ecosystems. Cooperation between industry, government and scientists has helped to improve sustainability and facilitated the meeting of market-based incentives for more responsible fisheries. Research includes ecosystem modelling, spatial analysis and ecosystem risk assessment with increasing research focus on social and economic aspects of the fishery. A four-year cooperative experiment to quantify the effect of trawling on benthic community structure is being planned. The food requirements of top predators still need to be included in the TAC-setting formulae and more social and economic research is needed. This paper also demonstrates how NGO initiatives such as Marine Stewardship Council certification and the Southern African Sustainable Seafood Initiative, a traffic light system of classifying seafood for consumers, have contributed to responsible fishing

  14. Ocean Bottom Pressure Measurements Off Sanriku, Japan

    NASA Astrophysics Data System (ADS)

    Sato, T.; Fujimoto, H.; Matsumoto, K.; Tamura, Y.; Higashi, T.; Nishino, M.; Hino, R.; Kanazawa, T.

    2003-12-01

    Variable motions of the ocean are changing the Earth's gravity field. For example, mass exchange in the Pacific Ocean is considered to be the most probable source of the recent rapid and large change in the J2 term, which may be related to the ENSO event in 1997 (Cox and Chao, 2002). The actual ocean mass exchange related to that event was also observed from ocean bottom pressure records (OBPRs) offshore of Peru (Fujimoto et al., 2003). On the other hand, satellite altimetry measurements, such as TOPEX/Poseidon (T/P), enable us to estimate the oceanic effect on gravity observations using globally-gridded data for sea surface height (SSH) variability. However, the altimeter data are affected by steric changes in the ocean, which should not contribute to the observed gravity changes (for example, Sato et al., 2001). In order to examine the relation among the mass exchange in the oceans, SSH variation, and gravity changes, we began a three-year observation project in 2001 to measure the ocean bottom pressure changes at the three crossover points of the T/P satellite off Sanriku, Japan: 143.1E, 39.2N (Point-A); 146.0E, 39.2N (Point-B); and 144.6E, 41.5N (Point-N). The data are sampled at an interval of one minute. Here, we will report the analysis results for the OBPR data for the two years since the beginning of the observations. Although the records at Point-N show a peculiar time variation, we obtained clear tidal signals at Point-A and Point-B. We compared the tidal analysis results with a global ocean tide model, NAO99b (Matsumoto et al., 2000), and we confirmed that, at both Point-A and Point-B, the predicted tides agree to the actual observations within the difference of 1 % in amplitude for the four major tidal waves: M2, S2, K1 and O1. This suggests that it may be possible to correct the tidal effect on the satellite gravity data with an accuracy of about 1 % by using recent global tide models. We also compared residuals of the OBPR data, which were obtained

  15. Near real-time noise removal for the Monterey Ocean Bottom Broadband (MOBB) seismic station data

    NASA Astrophysics Data System (ADS)

    Guinois, M.; Zheng, Z.; Taira, T.; Romanowicz, B. A.

    2012-12-01

    The Monterey Ocean Bottom Broadband (MOBB) observatory, located 40 km offshore central California, at a water depth of 1000 m, provides important complementary coverage of the San Andreas Fualt system to the land-based network. First installed in 2002, it is arguably the longest lived ocean bottom broadband seismic station. It includes a three-component broadband Guralp CMG-1T seismometer and a collocated differential pressure gauge (DPG) to measure the local water pressure continuously, as well as a current meter. After 7 years of autonomous operation, in February 2009, MOBB was successfully connected to the MARS cable (http://www.mbari.org/mars), and the data have been available in real time at the Northern California Earthquake Data Center (Romanowicz et al., 2009). However, the usage of MOBB data has been limited because of the noisy character of the data, in particular at periods of interest for regional moment tensor studies (20-100 sec), due to the ocean infragravity waves. Crawford and Webb (2000) demonstrated that there is a strong correlation between the water pressure and the vertical component of seafloor ground velocity in the infragravity wave band. Applying this to MOBB vertical component data, a transfer function (TF) was determined and utilized to successfully deconvolve the pressure-correlated noise from the vertical component of MOBB seismograms (Dolenc et al., 2007) in the period band 20-200 sec. Romanowicz et al. (2003, 2009) presented examples of how the cleaned MOBB data contribute to the determination of source parameters and regional structure. These past efforts, however, have been mostly case studies for illustration purpose. In this study, we systematically process all the available MOBB data since 2009 (because the cable was trawled, about a year of data is missing from February 2010 to June 2011). We calculate the TF over time and find that it is generally very stable, except for one change in 2010 due to an instrument replacement. Two

  16. Overview of the Ocean Bottom Seismology Component of the Cascadia Initiative (Invited)

    NASA Astrophysics Data System (ADS)

    Toomey, D. R.; Allen, R. M.; Collins, J. A.; Dziak, R. P.; Hooft, E. E.; Livelybrooks, D.; McGuire, J. J.; Schwartz, S. Y.; Tolstoy, M.; Trehu, A. M.; Wilcock, W. S.

    2013-12-01

    We report on the experimental progress of the ocean bottom seismology component of the Cascadia Initiative (CI). The CI is an onshore/offshore seismic and geodetic experiment that takes advantage of an Amphibious Array Facility (AAF) to study questions ranging from megathrust earthquakes to volcanic arc structure to the formation, deformation and hydration of the Juan de Fuca and Gorda plates. This diverse set of objectives are all components of understanding the overall subduction zone system and require an array that provides high quality data that crosses the shoreline and encompasses relevant plate boundaries. In October 2010, an open community workshop was convened in Portland, Oregon that produced a series of recommendations to maximize the scientific return of the CI and to develop deployment plans for the offshore component of the experiment. The NSF Cascadia Initiative Workshop Report1 presents the scientific objectives of the CI, the resources involved and the community-defined ocean bottom seismometer (OBS) deployment plan. There are several noteworthy aspects of the CI: The CI is the first to utilize a new generation of OBSs that are designed to withstand trawling by fisheries, thus allowing the collection of seismic data in the shallow water that overlies much of the Cascadia megathrust. The CI is a plate-scale experiment that provides a unique opportunity to study the structure and dynamics of an entire oceanic plate, from its birth at a spreading center to its subduction beneath a continental plate. Together with the land stations that are part of the amphibious array and other land networks, the OBSs will provide coverage at a density comparable to the Transportable Array of Earthscope from the volcanic arc out to the Pacific-Juan de Fuca spreading center segments. The CI is a community experiment that provides open access to all data via the IRIS Data Management Center, thus ensuring that the scientific return from the investment of resources is

  17. Bottom-feeding for blockbuster businesses.

    PubMed

    Rosenblum, David; Tomlinson, Doug; Scott, Larry

    2003-03-01

    Marketing experts tell companies to analyze their customer portfolios and weed out buyer segments that don't generate attractive returns. Loyalty experts stress the need to aim retention programs at "good" customers--profitable ones- and encourage the "bad" ones to buy from competitors. And customer-relationship-management software provides ever more sophisticated ways to identify and eliminate poorly performing customers. On the surface, the movement to banish unprofitable customers seems reasonable. But writing off a customer relationship simply because it is currently unprofitable is at best rash and at worst counterproductive. Executives shouldn't be asking themselves, How can we shun unprofitable customers? They need to ask, How can we make money off the customers that everyone else is shunning? When you look at apparently unattractive segments through this lens, you often see opportunities to serve those segments in ways that fundamentally change customer economics. Consider Paychex, a payroll-processing company that built a nearly billion-dollar business by serving small companies. Established players had ignored these customers on the assumption that small companies couldn't afford the service. When founder Tom Golisano couldn't convince his bosses at Electronic Accounting Systems that they were missing a major opportunity, he started a company that now serves 390,000 U.S. customers, each employing around 14 people. In this article, the authors look closely at bottom-feeders--companies that assessed the needs of supposedly unattractive customers and redesigned their business models to turn a profit by fulfilling those needs. And they offer lessons other executives can use to do the same.

  18. Formation and Variability of Antarctic Bottom Water off Cape Darnley: the Fourth Antarctic Bottom Water

    NASA Astrophysics Data System (ADS)

    Ohshima, K. I.; Nakayama, Y.; Fukamachi, Y.; Matsumura, Y.; Nihashi, S.; Tamura, T.; Kitade, Y.; Hirano, D.; Shimizu, D.; Aoki, S.

    2016-02-01

    It has been recognized that Antarctic Bottom Water (AABW) is formed in the Weddell Sea, the Ross Sea and off the Adélie Coast. Although a fourth variety of AABW has been identified in the eastern sector of the Weddell-Enderby Basin, its production has never been observed. Satellite-derived estimates of sea-ice production suggest that the Cape Darnley Polynya, located northwest of the Amery Ice Shelf, has the second highest ice production. We have conducted mooring observations since 2008 off and in the Cape Darnley Polynya, and revealed that this polynya is the missing source of the AABW. Moored instruments observed overflows of newly formed AABW, bottom-intensified, cascading down the canyon. Cold and dense AABW of about 300m thick flows down at fairly regular periods of 4-5 days. We propose to name this AABW Cape Darnley Bottom Water (CDBW). We estimate that 0.3-0.7 × 106 m3 s-1 of dense shelf water is transformed into CDBW. The CDBW migrates westward and increases its volume, to ultimately constitute part of the AABW in the Weddell Sea, 15-30% of the Atlantic AABW production. Detailed understanding of descending pathways of dense water, importance of topographic depression and sea-ice formation for the CDBW production, and mechanisms responsible for the periodic downslope flow are difficult to be understood only from observations. Thus, we have also conducted numerical simulations using a nonhydrostatic model. The model is forced by surface salt flux due to sea ice production, estimated from AMSR-E data and a heat budget calculation. We have reproduced the CDBW formation and associated periodic downslope flow of dense water. Intense sea ice formation is the most important factor in the CDBW formation. Together with simplified experiments and analytical interpretations, the mechanism responsible for the periodic downslope flow of dense water is further analyzed. The period of dense water outflow is regulated primarily by the topographic beta effect.

  19. Surveying Future Surveys

    NASA Astrophysics Data System (ADS)

    Carlstrom, John E.

    2016-06-01

    The now standard model of cosmology has been tested and refined by the analysis of increasingly sensitive, large astronomical surveys, especially with statistically significant millimeter-wave surveys of the cosmic microwave background and optical surveys of the distribution of galaxies. This talk will offer a glimpse of the future, which promises an acceleration of this trend with cosmological information coming from new surveys across the electromagnetic spectrum as well as particles and even gravitational waves.

  20. Getting to the Bottom of L2 Listening Instruction: Making a Case for Bottom-Up Activities

    ERIC Educational Resources Information Center

    Siegel, Joseph; Siegel, Aki

    2015-01-01

    This paper argues for the incorporation of bottom-up activities for English as a foreign language (EFL) listening. It discusses theoretical concepts and pedagogic options for addressing bottom-up aural processing in the EFL classroom as well as how and why teachers may wish to include such activities in lessons. This discussion is augmented by a…