WorldWideScience

Sample records for vessel trawl surveys

  1. Winter Bottom Trawl Survey

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The standardized NEFSC Winter Bottom Trawl Survey was initiated in 1992 and covered offshore areas from the Mid-Atlantic to Georges Bank. Inshore strata were covered...

  2. Fall Bottom Trawl Survey

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The standardized NEFSC Fall Bottom Trawl Survey was initiated in 1963 and covered an area from Hudson Canyon, NY to Nova Scotia, Canada. Throughout the years,...

  3. Spring Bottom Trawl Survey

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The standardized NEFSC Spring Bottom Trawl Survey was initiated in 1968 and covered an area from Cape Hatteras, NC, to Nova Scotia, Canada, at depths >27m....

  4. Great Lakes Research Vessel Operations 1958-2016: Trawl

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — All trawl data represented here expand upon vessel operations (OP table) data, all of which are collected by the United States Geological Survey, Great Lakes Science...

  5. Summer Bottom Trawl Survey

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Sampling the coastal waters of the Gulf of Maine using the Northeast Fishery Science Center standardized bottom trawl has been problematic due to large areas of hard...

  6. NEFSC 2002 Spring Bottom Trawl Survey (AL0204, EK500)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The NEFSC bottom trawl survey is a fisheries independent, multi-species survey that provides the primary scientific data for fisheries assessments in the U.S....

  7. NEFSC 1998 Fall Bottom Trawl Survey (AL9811, EK500)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The NEFSC bottom trawl survey is a fisheries independent, multi-species survey that provides the primary scientific data for fisheries assessments in the U.S....

  8. NEFSC 2009 Fall Bottom Trawl Survey (HB0905, EK60)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The NEFSC bottom trawl survey is a fisheries independent, multi-species survey that provides the primary scientific data for fisheries assessments in the U.S....

  9. NEFSC 2009 Spring Bottom Trawl Survey (HB0901, EK60)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The NEFSC bottom trawl survey is a fisheries independent, multi-species survey that provides the primary scientific data for fisheries assessments in the U.S....

  10. NEFSC 2011 Spring Bottom Trawl Survey (HB1102, EK60)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The NEFSC bottom trawl survey is a fisheries independent, multi-species survey that provides the primary scientific data for fisheries assessments in the U.S....

  11. NEFSC 2003 Fall Bottom Trawl Survey (AL0305, EK500)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The NEFSC bottom trawl survey is a fisheries independent, multi-species survey that provides the primary scientific data for fisheries assessments in the U.S....

  12. NEFSC 2007 Bottom Trawl Survey Calibration (HB0710, EK60)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The NEFSC bottom trawl survey is a fisheries independent, multi-species survey that provides the primary scientific data for fisheries assessments in the U.S....

  13. NEFSC 2014 Fall Bottom Trawl Survey (HB1405, EK60)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The NEFSC bottom trawl survey is a fisheries independent, multi-species survey that provides the primary scientific data for fisheries assessments in the U.S....

  14. NEFSC 1999 Fall Bottom Trawl Survey (AL9911, EK500)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The NEFSC bottom trawl survey is a fisheries independent, multi-species survey that provides the primary scientific data for fisheries assessments in the U.S....

  15. NEFSC 2001 Fall Bottom Trawl Survey (AL0110, EK500)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The NEFSC bottom trawl survey is a fisheries independent, multi-species survey that provides the primary scientific data for fisheries assessments in the U.S....

  16. NEFSC 2000 Fall Bottom Trawl Survey (Al0006, EK500)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The NEFSC bottom trawl survey is a fisheries independent, multi-species survey that provides the primary scientific data for fisheries assessments in the U.S....

  17. NEFSC 2004 Fall Bottom Trawl Survey (AL0409, EK500)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The NEFSC bottom trawl survey is a fisheries independent, multi-species survey that provides the primary scientific data for fisheries assessments in the U.S....

  18. NEFSC 2007 Bottom Trawl Survey Calibration (HB0711, EK60)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The NEFSC bottom trawl survey is a fisheries independent, multi-species survey that provides the primary scientific data for fisheries assessments in the U.S....

  19. NEFSC 2013 Spring Bottom Trawl Survey (HB1301, EK60)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The NEFSC bottom trawl survey is a fisheries independent, multi-species survey that provides the primary scientific data for fisheries assessments in the U.S....

  20. NEFSC 2015 Spring Bottom Trawl Survey (HB1501, EK60)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The NEFSC bottom trawl survey is a fisheries independent, multi-species survey that provides the primary scientific data for fisheries assessments in the U.S....

  1. NEFSC 2008 Fall Bottom Trawl Survey (AL0803, EK500)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The NEFSC bottom trawl survey is a fisheries independent, multi-species survey that provides the primary scientific data for fisheries assessments in the U.S....

  2. NEFSC 2010 Spring Bottom Trawl Survey (HB1002, EK60)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The NEFSC bottom trawl survey is a fisheries independent, multi-species survey that provides the primary scientific data for fisheries assessments in the U.S....

  3. NEFSC 2000 Fall Bottom Trawl Survey (AL0007, EK500)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The NEFSC bottom trawl survey is a fisheries independent, multi-species survey that provides the primary scientific data for fisheries assessments in the U.S....

  4. NEFSC 2004 Winter Bottom Trawl Survey (AL0401, EK500)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The NEFSC bottom trawl survey is a fisheries independent, multi-species survey that provides the primary scientific data for fisheries assessments in the U.S....

  5. NEFSC 2012 Fall Bottom Trawl Survey (HB1206, EK60)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The NEFSC bottom trawl survey is a fisheries independent, multi-species survey that provides the primary scientific data for fisheries assessments in the U.S....

  6. NEFSC 2008 Fall Bottom Trawl Survey (HB0807, EK60)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The NEFSC bottom trawl survey is a fisheries independent, multi-species survey that provides the primary scientific data for fisheries assessments in the U.S....

  7. NEFSC 2002 Fall Bottom Trawl Survey (AL0210, EK500)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The NEFSC bottom trawl survey is a fisheries independent, multi-species survey that provides the primary scientific data for fisheries assessments in the U.S....

  8. NEFSC 2013 Fall Bottom Trawl Survey (HB1304, EK60)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The NEFSC bottom trawl survey is a fisheries independent, multi-species survey that provides the primary scientific data for fisheries assessments in the U.S....

  9. NEFSC 2015 Fall Bottom Trawl Survey (HB1506, EK60)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The NEFSC bottom trawl survey is a fisheries independent, multi-species survey that provides the primary scientific data for fisheries assessments in the U.S....

  10. NEFSC 2012 Spring Bottom Trawl Survey (HB1201, EK60)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The NEFSC bottom trawl survey is a fisheries independent, multi-species survey that provides the primary scientific data for fisheries assessments in the U.S....

  11. NEFSC 2011 Fall Bottom Trawl Survey (HB1105, EK60)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The NEFSC bottom trawl survey is a fisheries independent, multi-species survey that provides the primary scientific data for fisheries assessments in the U.S....

  12. NEFSC 2002 Winter Bottom Trawl Survey (AL0203, EK500)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The NEFSC bottom trawl survey is a fisheries independent, multi-species survey that provides the primary scientific data for fisheries assessments in the U.S....

  13. NEFSC 2005 Winter Bottom Trawl Survey (AL0502, EK500)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The NEFSC bottom trawl survey is a fisheries independent, multi-species survey that provides the primary scientific data for fisheries assessments in the U.S....

  14. NEFSC 2004 Spring Bottom Trawl Survey (AL0403, EK500)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The NEFSC bottom trawl survey is a fisheries independent, multi-species survey that provides the primary scientific data for fisheries assessments in the U.S....

  15. NEFSC 2005 Fall Bottom Trawl Survey (AL0508, EK500)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The NEFSC bottom trawl survey is a fisheries independent, multi-species survey that provides the primary scientific data for fisheries assessments in the U.S....

  16. NEFSC 2005 Fall Bottom Trawl Survey (AL0509, EK500)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The NEFSC bottom trawl survey is a fisheries independent, multi-species survey that provides the primary scientific data for fisheries assessments in the U.S....

  17. NEFSC 2014 Spring Bottom Trawl Survey (HB1401, EK60)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The NEFSC bottom trawl survey is a fisheries independent, multi-species survey that provides the primary scientific data for fisheries assessments in the U.S....

  18. NEFSC 2008 Spring Bottom Trawl Survey (AL0801, EK500)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The NEFSC bottom trawl survey is a fisheries independent, multi-species survey that provides the primary scientific data for fisheries assessments in the U.S....

  19. NEFSC 2008 Spring Bottom Trawl Survey (HB0802, EK60)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The NEFSC bottom trawl survey is a fisheries independent, multi-species survey that provides the primary scientific data for fisheries assessments in the U.S....

  20. West Coast Groundfish Bottom Trawl Survey Data - Annual West Coast time series groundfish trawl data collection survey

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Members of the Fishery Resource Analysis and Monitoring Division Survey Team conduct an annual West Coast Groundfish Bottom Trawl Survey from May - October each...

  1. AFSC/RACE/GAP/Palsson: Globe navigation data collected during the Gulf of Alaska and Aleutian Islands Biennial Bottom Trawl Survey

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — These data are haul positions and haul depths collected throughout the Gulf of Alaska and Aleutian Islands groundfish trawl surveys. Vessel positions are recorded...

  2. A robust method for compiling trawl survey data used in the assessment of central Baltic cod ( Gadus morhua L.)

    DEFF Research Database (Denmark)

    Sparholt, H.; Tomkiewicz, Jonna

    2000-01-01

    Annual stratified bottom trawl surveys have been used since 1982 to estimate cod abundance in the central Baltic Sea. Catch at age from national research vessels is included in a common database, but data compilation is hampered by large differences in fishing power between vessels, mainly due...... of adult cod of all ages aggregated to minimise the effects of age determination discrepancies. The established index of spawning stock biomass did not correlate significantly better with VPA estimates than simpler indices ignoring depth stratification and fishing power. However, the method is preferable...... because it considers factors known to influence survey trawl catches....

  3. AFSC/ABL: Frederick Sound Echo-integrated Trawl Survey, 2001 to 2004

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The acoustic trawl database for Frederick Sounds echo-trawl survey was conducted from 2001 to 2004. The surveys were conducted throughout most of the southern part...

  4. AFSC/ABL: Lynn Canal Echo-Integrated Trawl Surveys, 2001-2004

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The acoustic trawl database for Lynn Canals echo-trawl survey was conducted from 2001 to 2004 throughout southern Lynn Canal in southeast Alaska. Acoustic surveys...

  5. Demersal trawl surveys show ecological gradients in Southwest ...

    African Journals Online (AJOL)

    We assessed the richness, diversity and community structure of demersal fish and benthic invertebrates caught by trawl nets along the deep shelf and upper continental slope of the Southwest (SW) Indian Ocean. Four depth-stratified surveys were undertaken in 2011-2012, in Kenya, Tanzania, Mozambique and ...

  6. A dataset from bottom trawl survey around Taiwan

    Directory of Open Access Journals (Sweden)

    Kwang-tsao Shao

    2012-05-01

    Full Text Available 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.

  7. SWFSC FED Mid Water Trawl Juvenile Rockfish Survey, Surface Data, 1987-2015

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — SWFSC FED Mid Water Trawl Juvenile Rockfish Survey: Station Information and Surface Data. Surveys have been conducted along the central California coast in May/June...

  8. NEFSC 2008 Spring Bottom Trawl Survey - Site Specific Calibration (HB0803, EK60)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The NEFSC bottom trawl survey is a fisheries independent, multi-species survey that provides the primary scientific data for fisheries assessments in the U.S....

  9. SWFSC FED Mid Water Trawl Juvenile Rockfish Survey, CTD Data, 1987-2015

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — SWFSC FED Mid Water Trawl Juvenile Rockfish Survey: CTD Data. Surveys have been conducted along the central California coast in May/June every year since 1983. In...

  10. Precision in systematic trawl surveys as assessed from replicate ...

    African Journals Online (AJOL)

    Local variability was analysed as random noise, modelled and later reapplied on single vessel data series to evaluate the effect of sample size and replicates on the survey mean. In a survey with 200 stations, local sample noise accounted for about 4% of the variability in the survey mean. Alternatively, running series of ...

  11. AFSC/RACE/MACE: Results of 2015 acoustic trawl survey Shumagin/Sanak/PWS DY1502

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The surveys primary objective was to collect acoustic data and trawl information to estimate midwater abundance and distribution of walleye pollock (Gadus...

  12. Oceanographic data - Integrated acoustic and trawl survey of Pacific hake off the Pacific Coast

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Integrated acoustic and trawl surveys are used to assess the distribution, biomass, and biology of Pacific hake along the Pacific coasts of the United States and...

  13. Acoustic data - Integrated acoustic and trawl survey of Pacific hake off the Pacific Coast

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Integrated acoustic and trawl surveys are used to assess the distribution, biomass, and biology of Pacific hake along the Pacific coasts of the United States and...

  14. Biological data - Integrated acoustic and trawl survey of Pacific hake off the Pacific Coast

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Integrated acoustic and trawl surveys are used to assess the distribution, biomass, and biology of Pacific hake along the Pacific coasts of the United States and...

  15. AFSC/RACE/MACE: Results of 2012 Chukchi Sea Acoustic/Trawl Survey

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — We conducted acoustic-trawl (AT) surveys of the Alaska northern Bering and Chukchi Seas during ice-free periods with a focus on Arctic cod (Boreogadus saida), a key...

  16. Bottom Trawl Survey Protocol Development (HB0706, EK60)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Cruise objectives include: 1) Investigate performance characteristics of new research bottom trawl; 2) Develop standard operating procedures for the NEFSC Bottom...

  17. Diel effects on bottom-trawl survey catch rates of shallow- and deep ...

    African Journals Online (AJOL)

    Fishing in depths shallower than 400 m outside daylight hours should therefore be avoided in order to reduce bias and ensure consistency in abundance estimates from surveys. Keywords: Benguela Current system, consistency of survey indices, efficiency of bottom-trawl surveys, negative binomial GAM, transect survey ...

  18. Coastal Logbook Survey (Vessels)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This data set contains catch (landed catch) and effort for fishing trips made by vessels that have been issued a Federal permit for the Gulf of Mexico reef fish,...

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

    Science.gov (United States)

    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.

  20. Inshore small-mesh trawling survey of the Cape south coast. Part 4 ...

    African Journals Online (AJOL)

    importance of this with respect to inshore trawling is noted. ... Most studies on the biology of South African ichthyofauna ... marine fish. With this in mind, this study provides some infor- mation on fish that occur in the shallow marine environment. Methods. The survey was conducted along the southern Cape coast be-.

  1. AFSC/RACE/SAP: Detailed Crab Data From NOAA Fisheries Service 2012 Chukchi Sea Bottom Trawl Surveys

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This dataset contains detailed crab data collected from the 2012 NOAA/NMFS/AFSC/RACE crab-groundfish bottom trawl survey of the Chukchi Sea. 71 survey stations were...

  2. Deep Sea Coral voucher sequence dataset - Identification of deep-sea corals collected during the 2009 - 2014 West Coast Groundfish Bottom Trawl Survey

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Data for this project resides in the West Coast Groundfish Bottom Trawl Survey Database. Deep-sea corals are often components of trawling bycatch, though their...

  3. AFSC/RACE/GAP/Palsson: Gulf of Alaska and Aleutian Islands Biennial Bottom Trawl Survey estimates of catch per unit effort, biomass, population at length, and associated tables

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The GOA/AI Bottom Trawl Estimate database contains abundance estimates for the Alaska Biennial Bottom Trawl Surveys conducted in the Gulf of Alaska and the Aleutian...

  4. Acoustic-Trawl Survey of Walleye Pollock on the Eastern Bering Sea Shelf (DY1407, EK60)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — National Marine Fisheries Service (NMFS), Alaska Fisheries Science Center (AFSC) conducted an acoustic-trawl (AT) stock assessment survey on the eastern Bering Sea...

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

    Science.gov (United States)

    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.

  6. Morphospecies and taxonomic sufficiency of benthic megafauna in scientific bottom trawl surveys

    Science.gov (United States)

    Brind'Amour, Anik; Laffargue, Pascal; Morin, Jocelyne; Vaz, Sandrine; Foveau, Aurélie; Le Bris, Hervé

    2014-01-01

    Scientific fisheries surveys routinely identify a large diversity of commercial and non-commercial benthic megainvertebrates that could provide useful information for Marine Strategy Framework Directive (MSFD) descriptors. Species is obviously the basic taxonomic level to which most ecological studies and theories refer. Identification at this level of organization is indeed always preferred over any other taxonomic level. Nevertheless, aggregation of species to higher taxonomic levels may be unavoidable sometimes, since errors of identification are known or suspected to occur in many surveys. Using analyses of taxonomic sufficiency (identification of organisms at various taxonomic resolutions) and groups of morphospecies (taxa identified easily by non-experts on the basis of evident morphological traits), this study aims to quantify the loss of ecological information incurred by partial identification of benthic megafauna in bottom trawl surveys in order to put such data to good use. The analyses were conducted on five scientific surveys representing a large range of geographical areas (from 150 km2 to 150 000 km2) and environmental conditions. Results show that genus, family and, particularly, morphospecies are good surrogates for species identification in community analyses. We suggest that bottom trawl surveys can provide reliable megafauna data that may usefully complete those obtained by grab surveys. The use of morphospecies could lead to new strategies, combining different datasets to provide indicators for MSFD descriptors (e.g. D6).

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

    Science.gov (United States)

    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.

  8. A statistical evaluation of the design and precision of the shrimp trawl survey off West Greenland

    DEFF Research Database (Denmark)

    Folmer, Ole; Pennington, M.

    2000-01-01

    Stocks of Pandalus borealis off West Greenland have been assessed using a research trawl survey since 1988. The survey has used a design of randomly placed stations, stratified ton depth data where available, using small blocks elsewhere), with sampling effort proportional to stratum area. In some...... years, a two-stage adaptive sampling scheme was used to place more stations into strata with large first-stage variation in catches. The design of the survey was reviewed in 1998. Modifications in survey design suggested were to shorten tow duration, to pool strata so that effort could be allocated more...... efficiently, to put a higher proportion of stations in high- density areas and to abandon two-stage sampling. All these changes were implemented for the 1998 survey, except that tow duration was reduced to 30 min at 25% of the stations. To analyze the-efficiency of the present survey design, various...

  9. Caribbean Marine Mammal Assessment Vessel Surveys

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — These data sets are a compilation of large vessel surveys for marine mammal stock assessments in Caribbean waters conducted during 2000-2001. These surveys were...

  10. 75 FR 73979 - Fisheries of the Northeastern United States; Discard Provision for Herring Midwater Trawl Vessels...

    Science.gov (United States)

    2010-11-30

    ... full net alongside the vessel, where the end of the net is hoisted aboard in order to attach the pump... NE Multispecies CA I Hook Gear Haddock Special Access Program (SAP). These comments included... targeting groundfish through the NE Multispecies CA I, Hook Gear Haddock Special Access Program had to meet...

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

    Science.gov (United States)

    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.

  12. Caribbean PR Logbook Survey (Vessels)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This data set contains catch (landed catch) and effort for fishing trips made by vessels fishing in Puerto Rico. The catch and effort data for the entire trip are...

  13. Coastal Discard Logbook Survey (Vessels)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This data set contains data on the type and amount of marine resources that are discarded or interacted with by vessels that are selected to report to the Southeast...

  14. Atlantic Marine Mammal Assessment Vessel Surveys

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — These data sets are a compilation of large vessel surveys for marine mammal stock assessments in South Atlantic (Florida to Maryland) waters from 1994 to the...

  15. Development of energy efficient mid-water trawls to Murmansk trawl fleets

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1996-12-01

    Two experimental trawls were designed as a joint task between the Danish partners and the Russian trawler fleets which were going to test them. The new design incorporate use of modern Western high strength material. The engineering performance of the trawls was analysed using computer based simulation programs and flume tank tests. The new designs were compared with two conventional trawls used by the Russian partners with respect to overall geometry and towing resistance. The new trawls have better performance than the conventional trawls. The vertical opening in the trawl mouth is greater and the towing resistance is less. The trawls fishing capacity was tested and compared with the conventional trawls on commercial fishing trips in August and September 1996. One trawl of a typical Danish two bridle design was far better than the corresponding Russian trawl. In some fisheries the catch per haul was more than four times the catch of the Russian trawl. The other trawl, a four bridle design, which was a compromise between Danish and Russian design philosophies had a catch efficiency comparable to the Russian trawl. The experimental trawls were both easier to tow than to conventional trawls. A reduction in the towing power of 20% for the trawl designed to MurmanRyprom and 30% for the Turbo trawl designed to Murmansk Trawl Fleet when towed at the same speed is foreseen. The reduction in the overall fuel consumption is estimated to 5% and 7% only due to the operation profile and the layout of the vessels. (LN)

  16. Coral by-catch in shrimp bottom trawl surveys in West Greenland waters (2010 – 2012)

    DEFF Research Database (Denmark)

    Jørgensbye, Helle; Arboe, Nanette Hammeken

    There have been zoological expeditions in Greenland waters since the 19th century documenting the sea life, including cold water corals. Coral trees (vernacular name for Paragorgia arborea) are mentioned as early as 1741 in the first natural history book about Greenland (Egede 1741). Due...... to the many expeditions and opportunistic collections by Greenlandic fisheries surveys, the species composition of West Greenlandic corals is fairly well known (Tendal and Heiner 2002), although observations of species new to Greenland are still being made (Jørgensen et al. 2013, Tendal et al. 2013......). The earlier collections of corals were not systematic and distribution patterns are poorly understood. Thus, more recently the Greenland Institute of Natural Resources started to collect cold water corals in a more systematic way to document the occurrence of corals in the bottom trawls made for the annual...

  17. AFSC/RACE/SAP: Detailed Crab Data From NOAA Fisheries Service Annual Eastern Bering Sea Summer Bottom Trawl Surveys 1975 - 2015

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This dataset contains detailed crab data collected from the annual NOAA/NMFS/AFSC/RACE crab-groundfish bottom trawl survey of the eastern Bering Sea continental...

  18. Shumagin Islands Acoustic-Trawl Survey of Walleye Pollock (DY1201, ME70)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The Midwater Assessment and Conservation Engineering (MACE) program of the Alaska Fisheries Science Center (AFSC) conducted an acoustic-trawl (AT) stock assessment...

  19. AFSC/RACE/MACE: Results of 2015 acoustic trawl survey Gulf of Alaska M1501

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Three trawl-resistant bottom- mounted moorings (TRBM) instrumented with newly developed autonomous battery powered 70 kHz split-beam echosounders were deployed in...

  20. Shelikof Strait Acoustic-Trawl Survey of Walleye Pollock (DY1203, ME70)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The Midwater Assessment and Conservation Engineering (MACE) program of the Alaska Fisheries Science Center (AFSC) conducted an acoustic-trawl (AT) stock assessment...

  1. AFSC/RACE/MACE: Results of 2014 acoustic trawl survey Bogoslof DY1402

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Scientists from the Midwater Assessment and Conservation Engineering (MACE) Program of the Alaska Fisheries Science Center (AFSC) regularly conduct acoustic-trawl...

  2. Cooperative Research Paired Trawl Sweep Comparison Study

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — In the spring of 2009, Northeast Fisheries Science Center (NEFSC) replaced the previous standard bottom trawl gear (Yankee 36) with a new standard survey trawl...

  3. Southeast Region Headboat Survey-Vessel list/Vessel Directory

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This is a database of vessels that have been on the SRHS through time, their owners/operators, marinas/docks and their contact information. This assists in...

  4. Spin gyroscope trawlers: profitability of renewing the consumer fleet with vessels equipped with independent spin gyroscope seine and trawl equipment

    National Research Council Canada - National Science Library

    Jorgensen, H.P

    1986-01-01

    The purpose of this report is to throw some light on the profitability of investing in new construction of the so-called spin gyroscope trawler, that is, a vessel which, from the outset, is equipped...

  5. Use of commercial vessels in survey augmentation: the size-frequency distribution

    Directory of Open Access Journals (Sweden)

    Eric N. Powell

    2006-09-01

    Full Text Available The trend towards use of commercial vessels to enhance survey data requires assessment of the advantages and limitations of various options for their use. One application is to augment information on size-frequency distributions obtained in multispecies trawl surveys where stratum boundaries and sampling density are not optimal for all species. Analysis focused on ten recreationally and commercially important species: bluefish, butterfish, Loligo squid, weakfish, summer flounder, winter flounder, silver hake (whiting, black sea bass, striped bass, and scup (porgy. The commercial vessel took 59 tows in the sampled domain south of Long Island, New York and the survey vessel 18. Black sea bass, Loligo squid, and summer flounder demonstrated an onshore-offshore gradient such that smaller fish were caught disproportionately inshore and larger fish offshore. Butterfish, silver hake, and weakfish were characterized by a southwest-northeast gradient such that larger fish were caught disproportionately northeast of the southwestern-most sector. All sizes of scup, striped bass, and bluefish were caught predominately inshore. Winter flounder were caught predominately offshore. The commercial vessel was characterized by an increased frequency of large catches for most species. Consequently, patchiness was assayed to be higher by the commercial vessel in nearly all cases. The size-frequency distribution obtained by the survey vessel for six of the ten species, bluefish, butterfish, Loligo squid, summer flounder, weakfish, and silver hake, could not be obtained by chance from the size-frequency distribution obtained by the commercial vessel. The difference in sample density did not significantly influence the size-frequency distribution. Of the six species characterized by significant differences in size-frequency distribution between boats, all but one was patchy at the population level and all had one or more size classes so characterized. Although the

  6. A comparative study of Northern Ireland's estuaries based on the results of beam trawl fish surveys

    Science.gov (United States)

    Harrison, Trevor D.; Armour, Neil D.; McNeill, Michael T.; Moorehead, Peter W.

    2017-11-01

    The fish communities of Northern Ireland's estuaries were described and compared using data collected with a modified beam trawl over a six year period from 2009 to 2014. Multivariate analyses identified four estuary groups based on variations in their physico-chemical attributes. These groups broadly corresponded with the distribution and variation of estuary geomorphic types identified around the Irish coast. The dominant fish species captured were also among the main species reported in other North East Atlantic estuaries. A significant link between the estuary types and their fish communities was found; each estuary group contained a somewhat distinctive fish community. The fish communities also showed a significant relationship with the physico-chemical characteristics of the estuaries. Differences in fish species composition are attributed to habitat and environmental preferences of key estuary-associated species.

  7. Caribbean ST Croix Logbook Survey (Vessels)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This data set contains catch (landed catch) and effort for fishing trips made by vessels fishing in St. Croix. The catch and effort data for the entire trip are...

  8. Caribbean ST Thomas trap Logbook Survey (Vessels)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This data set contains catch (landed catch) and effort for fishing trips made by vessels fishing in St. Thomas. The catch and effort data for the entire trip are...

  9. Large Pelagic Logbook Set Survey (Vessels)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This data set contains catch and effort for fishing trips that are taken by vessels with a Federal permit issued for the swordfish and sharks under the Highly...

  10. Large Pelagic Logbook Trip Survey (Vessels)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This data set contains catch and effort for fishing trips that are taken by vessels with a Federal permit issued for the swordfish and sharks under the Highly...

  11. Catcher Vessel Cost Earnings Data - Economic Data Collection for Monitoring the Economic Effects of the West Coast Groundfish Trawl Rationalization Program

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This project was initiated in response to regulation 50 CFR 660.114, which mandates that economic data be collected from every participant in the trawl...

  12. Fish survey, fishing duration and other data from net trawls and other gear from the COMMANDO as part of Outer Continental Shelf Environmental Assessment Program (OCSEAP) from 31 March 1978 to 19 March 1979 (NODC Accession 8100690)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Fish survey, fishing duration, and other data were collected from net trawls and other gear from the COMMANDO from 31 March 1978 to 19 March 1979. Data were...

  13. Fish survey, fishing duration, and other data from net trawls from the NORTH PACIFIC as part of Outer Continental Shelf Environmental Assessment Program (OCSEAP) from 25 April 1975 to 07 August 1975 (NODC Accession 7601822)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Fish survey, fishing duration, and other data were collected from net trawls from the NORTH PACIFIC from 25 April 1975 to 07 August 1975. Data were collected by the...

  14. Fish survey, fishing duration, and other data from net trawls in the Gulf of Alaska from the NORTH PACIFIC as part of Outer Continental Shelf Environmental Assessment Program (OCSEAP) from 03 May 1975 to 07 August 1975 (NODC Accession 7601886)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Fish survey, fishing duration, and other data were collected from net trawls in the Gulf of Alaska from the NORTH PACIFIC from 03 May 1975 to 07 August 1975. Data...

  15. Fish survey, fishing duration, and other data from net trawls from the BARGE and other platforms as part of Outer Continental Shelf Environmental Assessment Program (OCSEAP) from 16 June 1976 to 30 March 1977 (NODC Accession 7800030)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Fish survey, fishing duration, and other data were collected from net trawls from the BARGE and other platforms from 16 June 1976 to 30 March 1977. Data were...

  16. Fish survey, fishing duration, and other data from net trawls in the Gulf of Alaska from the NORTH PACIFIC as part of Outer Continental Shelf Environmental Assessment Program (OCSEAP) from 03 May 1975 to 07 August 1975 (NODC Accession 7601885)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Fish survey, fishing duration, and other data were collected from net trawls in the Gulf of Alaska from the NORTH PACIFIC from 03 May 1975 to 07 August 1975. Data...

  17. Fish survey, fishing duration, and other data from net and otter trawls from the BIG VALLEY as part of Outer Continental Shelf Environmental Assessment Program (OCSEAP) from 20 May 1976 to 30 June 1976 (NODC Accession 7601547)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Fish survey, fishing duration, and other data were collected from net and otter trawls from the BIG VALLEY from 20 May 1976 to 30 June 1976. Data were collected by...

  18. Fish survey, fishing duration, and other data from net trawls from the BARGE as part of Outer Continental Shelf Environmental Assessment Program (OCSEAP) from 24 June 1976 to 10 September 1976 (NODC Accession 7800146)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Fish survey, fishing duration, and other data were collected from net trawls from the BARGE from 24 June 1976 to 10 September 1976. Data were collected by the...

  19. Fish survey, fishing duration and other data from net trawls from the SEA STAR as part of Outer Continental Shelf Environmental Assessment Program (OCSEAP) from 29 April 1976 to 24 August 1976 (NODC Accession 7800273)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Fish survey, fishing duration, and other data were collected from net trawls from the SEA STAR from 29 April 1976 to 24 August 1976. Data were collected by Dames and...

  20. Fish survey, fishing duration, and other data from net trawls from the BARGE and other platforms as part of Outer Continental Shelf Environmental Assessment Program (OCSEAP) from 30 May 1977 to 13 October 1977 (NODC Accession 7800268)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Fish survey, fishing duration, and other data were collected from net trawls from the BARGE and other platforms from 30 May 1977 to 13 October 1977. Data were...

  1. Marine Fish and Shellfish Survey data from otter trawls in the Chukchi Sea from the OCEAN HOPE 3 and OSHORO MARU from 16 August 1990 to 31 July 1992 (NODC Accession 9400061)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Marine Fish and Shellfish Survey data were collected from otter trawls in the Chukchi Sea from the OCEAN HOPE. Data were collected by the University of Alaska from...

  2. Gulf of Mexico Marine Mammal Assessment Vessel Surveys

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — These data sets are a compilation of large vessel surveys for marine mammal stock assessments in the Gulf of Mexico from 1991 to the present. These are designed as...

  3. Inshore small-mesh trawling survey of the Cape south coast. Part 5 ...

    African Journals Online (AJOL)

    Etymology. The specific name is derived from the Thomas B. Davie, research vessel of the University of Cape Town. Decapoda. Family Processidae. Processa aequimana (paulson 1875). Previous records. Mozambique, Vietnam, Java, Japan. Material. SAM-AI8817, TBD.PM 26, 1 ovig C;?, CL 5,1 mm. Remarks. This would ...

  4. AFSC/RACE/MACE: Results of 2014 Acoustic-trawl survey of the Shumagin Islands and Sanak Trough dy1401

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The survey’s primary objective was to collect acoustic data and trawl information to estimate midwater abundance and distribution of walleye pollock (Gadus...

  5. AFSC/RACE/MACE: Results of 2012 Acoustic-trawl survey of the Shumagin Islands and Sanak Trough dy1201

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The survey’s primary objective was to collect acoustic data and trawl information to estimate midwater abundance and distribution of walleye pollock (Gadus...

  6. NEFSC 2000 Atlantic Herring Acoustic/Midwater Trawl Survey (DE0008, EK500)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The NEFSC Atlantic herring acoustic survey is a fisheries independent survey that provides scientific data for Atlantic herring assessments in the U.S. mid-Atlantic...

  7. NEFSC 1999 Atlantic Herring Acoustic/Midwater Trawl Survey (DE9909, EK500)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The NEFSC Atlantic herring acoustic survey is a fisheries independent survey that provides scientific data for Atlantic herring assessments in the U.S. mid-Atlantic...

  8. NEFSC 2004 Atlantic Herring Acoustic/Midwater Trawl Survey (DE0413, EK500)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The NEFSC Atlantic herring acoustic survey is a fisheries independent survey that provides scientific data for Atlantic herring assessments in the U.S. mid-Atlantic...

  9. NEFSC 2008 Atlantic Herring Acoustic/Midwater Trawl Survey (DE0809, EK500)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The NEFSC Atlantic herring acoustic survey is a fisheries independent survey that provides scientific data for Atlantic herring assessments in the U.S. mid-Atlantic...

  10. NEFSC 2012 Atlantic Herring Acoustic/Midwater Trawl Survey (PC1206, EK60)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The NEFSC Atlantic herring acoustic survey is a fisheries independent survey that provides scientific data for Atlantic herring assessments in the U.S. mid-Atlantic...

  11. NEFSC 1998 Atlantic Herring Acoustic/Midwater Trawl Survey (DE9810, EK500)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The NEFSC Atlantic herring acoustic survey is a fisheries independent survey that provides scientific data for Atlantic herring assessments in the U.S. mid-Atlantic...

  12. NEFSC 2009 Atlantic Herring Acoustic/Midwater Trawl Survey (DE0910, EK500)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The NEFSC Atlantic herring acoustic survey is a fisheries independent survey that provides scientific data for Atlantic herring assessments in the U.S. mid-Atlantic...

  13. NEFSC 2011 Atlantic Herring Acoustic/Midwater Trawl Survey (DE1108, EK60)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The NEFSC Atlantic herring acoustic survey is a fisheries independent survey that provides scientific data for Atlantic herring assessments in the U.S. mid-Atlantic...

  14. NEFSC 2005 Atlantic Herring Acoustic/Midwater Trawl Survey (DE0512, EK500)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The NEFSC Atlantic herring acoustic survey is a fisheries independent survey that provides scientific data for Atlantic herring assessments in the U.S. mid-Atlantic...

  15. NEFSC 2010 Atlantic Herring Acoustic/Midwater Trawl Survey (DE1010, EK60)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The NEFSC Atlantic herring acoustic survey is a fisheries independent survey that provides scientific data for Atlantic herring assessments in the U.S. mid-Atlantic...

  16. NEFSC 2001 Atlantic Herring Acoustic/Midwater Trawl Survey (DE0109, EK500)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The NEFSC Atlantic herring acoustic survey is a fisheries independent survey that provides scientific data for Atlantic herring assessments in the U.S. mid-Atlantic...

  17. NEFSC 2002 Atlantic Herring Acoustic/Midwater Trawl Survey (DE0208, EK500)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The NEFSC Atlantic herring acoustic survey is a fisheries independent survey that provides scientific data for Atlantic herring assessments in the U.S. mid-Atlantic...

  18. NEFSC 2003 Atlantic Herring Acoustic/Midwater Trawl Survey (DE0308, EK500)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The NEFSC Atlantic herring acoustic survey is a fisheries independent survey that provides scientific data for Atlantic herring assessments in the U.S. mid-Atlantic...

  19. NEFSC 2007 Atlantic Herring Acoustic/Midwater Trawl Survey (DE0710, EK500)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The NEFSC Atlantic herring acoustic survey is a fisheries independent survey that provides scientific data for Atlantic herring assessments in the U.S. mid-Atlantic...

  20. NEFSC 2006 Atlantic Herring Acoustic/Midwater Trawl Survey (DE0615, EK500)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The NEFSC Atlantic herring acoustic survey is a fisheries independent survey that provides scientific data for Atlantic herring assessments in the U.S. mid-Atlantic...

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

    Science.gov (United States)

    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.

  2. Fisheries Online Information System - Fishing vessel based survey of young-of-year groundfish along the Newport Hydrographic Line

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The Northwest Fisheries Science Center (NWFSC) conducts a comprehensive groundfish bottom trawl survey encompassing the U.S. West Coast between the borders with...

  3. CPS Trawl Life History Specimen Data

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Individual specimens measured (weight in grams and length in mm) and sexed from mainly targeted species caught during SWFSC-FRD fishery independent trawl surveys of...

  4. CPS Trawl Life History Length Frequency Data

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Length distribution of a subset of individuals from a species (mainly non-target) caught during SWFSC-FRD fishery independent trawl surveys of coastal pelagic...

  5. Differences in Size Selectivity and Catch Composition Between Two Bottom Trawls Used in High-Arctic Surveys of Bottom Fishes, Crabs and Other Demersal Macrofauna

    Science.gov (United States)

    Lauth, R.; Norcross, B.; Kotwicki, S.; Britt, L.

    2016-02-01

    Long-term monitoring of the high-Arctic marine biota is needed to understand how the ecosystem is changing in response to climate change, diminishing sea-ice, and increasing anthropogenic activity. Since 1959, bottom trawls (BT) have been a primary research tool for investigating fishes, crabs and other demersal macrofauna in the high-Arctic. However, sampling gears, methodologies, and the overall survey designs used have generally lacked consistency and/or have had limited spatial coverage. This has restricted the ability of scientists and managers to effectively use existing BT survey data for investigating historical trends and zoogeographic changes in high-Arctic marine populations. Two different BTs currently being used for surveying the high-Arctic are: 1) a small-mesh 3-m plumb-staff beam trawl (PSBT), and 2) a large-mesh 83-112 Eastern bottom trawl (EBT). A paired comparison study was conducted in 2012 to compare catch composition and the sampling characteristics of the two different trawl gears, and a size selectivity ratio statistic was used to investigate how the probability of fish and crab retention differs between the EBT and PBST. Obvious contrasting characteristics of the PSBT and EBT were mesh size, area-swept, tow speed, and vertical opening. The finer mesh and harder bottom-tending characteristics of the PSBT retained juvenile fishes and other smaller macroinvertebrates and it was also more efficient catching benthic infauna that were just below the surface. The EBT had a larger net opening with greater tow duration at a higher speed that covered a potentially wider range of benthic habitats during a single tow, and it was more efficient at capturing larger and more mobile organisms, as well as organisms that were further off bottom. The ratio statistic indicated large differences in size selectivity between the two gears for both fish and crab. Results from this investigation will provide a framework for scientists and mangers to better

  6. A Dataset of Deep-Sea Fishes Surveyed by Research Vessels in the Waters around Taiwan

    Directory of Open Access Journals (Sweden)

    Kwang-Tsao Shao

    2014-12-01

    Full Text Available 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. Changes in the Eastern Cape demersal inshore trawl fishery ...

    African Journals Online (AJOL)

    Changes in the Eastern Cape demersal inshore trawl fishery between 1967 and 1995. AJ Booth, T Hecht. Abstract. Changes in the Eastern Cape demersal inshore trawl fishery operating out of Port Elizabeth over a 28-year period from 1967 to 1995 are described. The fishery is restricted to vessels operating between ...

  8. Quality Surveillance on a Commercial Marine Survey Vessel

    Science.gov (United States)

    Green, Bob

    There is a recent trend amongst oil companies or oil field construction companies to leave Quality Control (QC) to the survey subcontractor. Increasingly they do not put their own survey QC representative on survey vessels they hire. This may be a mistake, although at this point the author, being himself an offshore QC representative, must confess to a vested interest.Quality assurance is a term which is often misunderstood. Even people who use the expression are vague about what it actually means in any given industry or how it should be applied in any particular situation. The confusion is compounded because the quality assurance (BS5750/lSO 9001 documentation), was written primarily for the manufacturing industry, and needs expert translation to apply to a service industry such as the commercial marine survey business.

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

    Science.gov (United States)

    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

  10. Modified Herring Trawl Fish Catch Data, Gulf of Alaska Fjords, 2004-2011

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — This dataset contains catch data from trawls at the sampling stations. We deployed a modified herring trawl in coastal waters within glacier fjords of Alaska....

  11. Fish assemblages in southern California using trawl data from the National Marine Fisheries Service

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Fish benthic trawls were completed by the National Marine Fisheries Service Groundfish Survey Program (NMFS GSP). Data from 477 fishery independent trawls ranging...

  12. Improving fishing effort descriptors: Modelling engine power and gear-size relations of five European trawl fleets

    DEFF Research Database (Denmark)

    Eigaard, Ole Ritzau; Rihan, Dominic; Graham, Norman

    2011-01-01

    Based on information from an international inventory of gears currently deployed by trawlers in five European countries, the relationship between vessel engine power and trawl size is quantified for different trawl types, trawling techniques and target species. Using multiplicative modelling it i...

  13. 76 FR 16611 - Proposed Information Collection; Comment Request; Socio-Economic Surveys of Vessel Owners, Permit...

    Science.gov (United States)

    2011-03-24

    ...-Economic Surveys of Vessel Owners, Permit Holders, and Crew in New England and Mid-Atlantic Fisheries... intends to collect socio-economic data from vessel owners, permit holders, hired captains, and crew... project. For the owners/permit holders' survey, NOAA is considering in-person interviewing, a phone survey...

  14. Fish survey, fishing duration, and other data from net trawls in the Bering Sea from NOAA Ship MILLER FREEMAN and other platforms as part of Outer Continental Shelf Environmental Assessment Program (OCSEAP) from 1975-08-07 to 1975-10-21 (NODC Accession 7601681)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Fish survey, fishing duration, and other data were collected from net trawls in the Bering Sea from NOAA Ship MILLER FREEMAN and other platforms from 07 August 1975...

  15. Fish survey, fishing duration, and other data from net trawls in the Bering Sea from NOAA Ship MILLER FREEMAN and other platforms as part of Outer Continental Shelf Environmental Assessment Program (OCSEAP) from 1976-04-01 to 1976-08-09 (NODC Accession 7700847)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Fish survey, fishing duration, and other data were collected from net trawls in the Bering Sea from NOAA Ship MILLER FREEMAN and other platforms from 01 April 1976...

  16. Fish survey, fishing duration and other data from otter trawls and scuba observations from NOAA Ship MILLER FREEMAN and other platforms as part of Outer Continental Shelf Environmental Assessment Program (OCSEAP) from 1977-11-04 to 1979-11-26 (NODC Accession 8100532)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Fish survey, fishing duration, and other data were collected from otter trawls and scuba diver observations from NOAA Ship MILLER FREEMAN and other platforms from 04...

  17. Fish survey, fishing duration, and other data from net trawls from NOAA Ship MILLER FREEMAN and other platforms as part of Outer Continental Shelf Environmental Assessment Program (OCSEAP) from 1975-05-03 to 1976-08-04 (NODC Accession 7800029)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Fish survey, fishing duration, and other data were collected from net trawls from NOAA Ship MILLER FREEMAN and other platforms from 03 May 1975 to 04 August 1976....

  18. Fish survey, fishing duration, and other data from net trawls in the Bering Sea and other locations from the G. B. REED and other platforms as part of Outer Continental Shelf Environmental Assessment Program (OCSEAP) from 21 September 1948 to 19 February 1976 (NODC Accession 7601767)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Fish survey, fishing duration, and other data were collected from net trawls in the Bering Sea and other locations from the G. B. REED and other platforms from 21...

  19. AFSC/RACE/MACE: Results of 2013 Acoustic-trawl survey of the Shumagin Islands, Sanak Trough, and Morzhovoi Bay dy1302

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The survey’s primary objective was to collect acoustic data and trawl information to estimate midwater abundance and distribution of walleye pollock (Gadus...

  20. 46 CFR 42.09-30 - Additional survey requirements for steel-hull vessels.

    Science.gov (United States)

    2010-10-01

    ... 46 Shipping 2 2010-10-01 2010-10-01 false Additional survey requirements for steel-hull vessels...-30 Additional survey requirements for steel-hull vessels. (a) In addition to the requirements in § 42..., peaks, bilges, machinery spaces, and bunkers shall be examined to determine the condition of the framing...

  1. The footprint of bottom trawling in European waters: distribution, intensity, and seabed integrity

    DEFF Research Database (Denmark)

    Eigaard, Ole Ritzau; Bastardie, Francois; Hinzen, N.T.

    2017-01-01

    Mapping trawling pressure on the benthic habitats is needed as background to support an ecosystem approach to fisheries management. The extent and intensity of bottom trawling on the European continental shelf (0-1000 m) was analysed from logbook statistics and vessel monitoring system data for 2...

  2. AFSC/NMML: Southeast Alaska Cetacean Vessel Surveys, 1991 - 2012

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — In 1991, NMML initiated cetacean studies with vessel coverage throughout inland waters of Southeast Alaska. Between 1991 and 1993, line-transect methodology was used...

  3. Caribbean ST Thomas all gears Logbook Survey (Vessels)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This data set contains catch (landed catch) and effort for fishing trips made by vessels fishing in St. Thomas. The catch and effort data for the entire trip are...

  4. AFSC/FMA/Vessel Assessment Logging

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Vessels fishing trawl gear, vessels fishing hook-and-line and pot gear that are also greater than 57.5 feet overall, and shoreside and floating processing facilities...

  5. AFSC/REFM: Digitized 2005 GOA Trawl Logbooks merged with Fish Ticket and Observer data

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The data include a full year of logbook forms for vessels 60-124 feet in length (the partial coverage fleet) that had participated in the trawl flatfish fishery of...

  6. Socio-economic Survey of Commercial Fishing Vessel Owners in the Northeast

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The Northeast Fisheries Science Center's Social Sciences Branch (SSB) conducted a survey of vessel owners participating in commercial fisheries in the New England...

  7. 50 CFR 660.112 - Trawl fishery-prohibitions.

    Science.gov (United States)

    2010-10-01

    ... is registered for use with a valid limited entry permit with a trawl gear endorsement, with the..., Biogenic 1, Biogenic 2, Grays Canyon, Biogenic 3, Astoria Canyon, Nehalem Bank/Shale Pile, Siletz Deepwater... that is not registered for use with a sector-appropriate Pacific whiting vessel license under § 660.26...

  8. Distribution of the Mediterranean hake populations (Merluccius merluccius smiridus Rafinesque, 1810 (Ostheichthyes: Gadiformes based on six years monitoring by trawl-surveys: some implications for management

    Directory of Open Access Journals (Sweden)

    Lidia Orsi Relini

    2002-06-01

    Full Text Available On the basis of trawl survey data collected during the MEDITS project (1994-1999, the distribution of Mediterranean hake populations was described in coastal areas corresponding to about three quarters of both the latitudinal and longitudinal extensions of the Mediterranean Sea, and in the 0-800 m range. Abundance and biomass indices (in terms of number and kg per km2 are presented in 15 geographical sectors and 40 subareas from the Alborán Sea to the Aegean Sea. A statistical analysis by generalized linear modelling performed on such indices per main national blocks (Greece, France, Italy and Spain, and considering the effects of the six years of sampling and the depth, showed that biomass increased from west to east, while for all areas the most significant depth effect appeared between 100 and 200 m, corresponding to the depth range that hosts most of the summer nursery areas. The overall size-frequency distributions in shelf and slope waters, average sizes and total mortality coefficient Z per sector showed that the bulk of the MEDITS samples consisted of young individuals and, with only a few exceptions (western Sardinia, central Aegean, a generalized condition of growth overfishing was apparent. However, no negative trend was found, either in biomass or in average size of fishes, during the six years of the present study. Recruitment patterns were studied by distinguishing the youngest fish as Gaussian groups (modal length from 6 to 9 cm total length in length-frequency distributions of each subarea and main stratum (shelf and slope. Considering the timing of MEDITS surveys (May-July, this approach emphasised the nurseries in the northern part of the western Mediterranean (Gulf of Lions, Ligurian Sea, northern Tyrrhenian Sea and in the northern central Mediterranean, where recruitment occurs mainly during spring. On the other hand, few recruits were found in part of the central and particularly in the eastern Mediterranean, where

  9. AFSC/RACE/EcoFOCI - Trawl catch data collected in support of FOCI assessment surveys and ecosystem observations in the Bering Sea and the Gulf of Alaska 1993 to Present

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The trawl database contains multiple tables of data. The ‘haul’ table contains the location, date, time and depth of the trawl haul. The ‘catch’ table contains the...

  10. Species selectivity in different sized topless trawl designs: Does size matter?

    DEFF Research Database (Denmark)

    Krag, Ludvig Ahm; Herrmann, Bent; Karlsen, Junita Diana

    2015-01-01

    Most demersal trawl fisheries are conducted in a multispecies setting, and the catch consists of severaldifferent species. An inherent challenge in such fisheries is to provide both biologically and economicallysustainable exploitation of individually fluctuating stocks and vessel- or fleet-speci...... Atlantic, topless trawls have been introducedas legal cod-selective trawl designs. However, this study demonstrates that identical gear modificationsmade to similar trawls of different sizes and used in the same fishery can lead to different results....... the small and large trawls, wefound a significant topless effect for haddock (Melanogramus aeglefinus) and no effect for Nephrops. ForAtlantic cod (Gadus morhua) we found a significant topless effect for the low headline trawl but no effectfor the high headline trawl. In both the eastern and western......Most demersal trawl fisheries are conducted in a multispecies setting, and the catch consists of severaldifferent species. An inherent challenge in such fisheries is to provide both biologically and economicallysustainable exploitation of individually fluctuating stocks and vessel- or fleet...

  11. 2013-2014 California Current Ecosystem (CCE14): Acoustic-Trawl Survey of Coastal Pelagic Fishes (Legs I and II); and Investigations of hake survey methods, life history, and associated ecosystem (Legs III and IV) (SH1405, EK60)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The 2014 acoustic-trawl method (ATM) project aboard Bell M. Shimada represents a joint effort between the SWFSC and the NWFSC in investigating elements of the...

  12. 2013-2014 California Current Ecosystem (CCE14): Acoustic-Trawl Survey of Coastal Pelagic Fishes (Legs I and II); and Investigations of hake survey methods, life history, and associated ecosystem (Legs III and IV) (SH1405, ME70)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The 2014 acoustic-trawl method (ATM) project aboard Bell M. Shimada represents a joint effort between the SWFSC and the NWFSC in investigating elements of the...

  13. 46 CFR 42.09-35 - Additional survey requirements for wood-hull vessels.

    Science.gov (United States)

    2010-10-01

    ... 46 Shipping 2 2010-10-01 2010-10-01 false Additional survey requirements for wood-hull vessels. 42.09-35 Section 42.09-35 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) LOAD LINES DOMESTIC AND FOREIGN VOYAGES BY SEA Load Line Assignments and Surveys-General Requirements § 42.09-35 Additional survey requirements for wood-hull...

  14. Impact and distribution of bottom trawl fishing on mud-bottom communities in the Kattegat

    DEFF Research Database (Denmark)

    Pommer, Christina Dahl; Olesen, Michael; Hansen, Jorgen L. S.

    2016-01-01

    Danish (2005-2009) and Swedish (2007-2009) vessels show that 95% of all trawling occurs below 22 m depth. Most activity takes place on homogeneous benthic habitats with muddy sediment at depths below the halocline and with almost the same salinity across the entire area. Furthermore, the estimate...... of the trawl activity and inter-correlation between trawl activity and depth-related community structures complicated interpretation of the results. Species with biological traits previously categorized as sensitive to physical disturbance showed higher abundance in areas with low trawl activity compared...... to areas with higher activity. Thus, the Kattegat has been impacted to an extent where areas with reference conditions for certain habitats below 22 m no longer exist. Consequently, it is unknown how the benthic communities would have appeared without trawl disturbance and, thus, difficult to determine...

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

    Directory of Open Access Journals (Sweden)

    Shengmao Zhang

    Full Text Available 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.

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

    Science.gov (United States)

    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.

  17. A SURVEY OF RETINA BASED DISEASE IDENTIFICATION USING BLOOD VESSEL SEGMENTATION

    Directory of Open Access Journals (Sweden)

    P Kuppusamy

    2016-11-01

    Full Text Available The colour retinal photography is one of the most essential features to identify the confirmation of various eye diseases. The iris is primary attribute to authenticate the human. This research work presents the survey and comparison of various blood vessel related feature identification, segmentation, extraction and enhancement methods. Additionally, this study is observed the various databases performance for storing the images and testing in minimal time. This paper is also provides the better performance techniques based on the survey.

  18. Effects of diel period and tow duration on estuarine fauna sampled with a beam trawl over bare sediment: Consequences for designing more reliable and efficient surveys

    Science.gov (United States)

    Rotherham, Douglas; Gray, Charles A.; Johnson, Daniel D.; Lokys, Paul

    2008-06-01

    The effects of diel period and tow duration (5, 10 and 20 min) on samples of estuarine fauna in a beam trawl, were tested over bare sediment in Tuggerah Lake (New South Wales, Australia). Mean catch rates (numbers of fish caught 5 min -1) were significantly larger at night for the total numbers of individuals and abundant, economically important species of fish and invertebrates (e.g. Gerres subfasciatus, Metapenaeus macleayi, Penaeus plebejus). Greater proportions of larger fish were also caught at night for some species (e.g. G. subfasciatus, Acanthopagrus australis, Rhabdosargus sarba), but not across all tow durations. Multivariate analyses detected dissimilarities in the composition and structure of assemblages between diel periods, which were driven by species caught predominately, or in larger proportions, at night. Short tows (5 min) were more efficient than longer tows (10 or 20 min) for sampling the diversity of species (i.e. most species were caught in the first 5 min of a tow). There were, however, no clear or consistent patterns relating to the effect of tow duration on the catch rates of other variables, the size ranges of abundant species, or the structure and composition of assemblages. Our data confirm that at night, bare sediment is an important habitat for a wide size- and species-range of estuarine fish and invertebrates. In future, more cost-effective and reliable information concerning these taxa would be achieved by sampling with the beam trawl at night, using tow durations of 5 min. We also highlight a problem inherent in the design of many studies of diel variation of fauna (i.e. the potential non-independence of data among day and night periods) and discuss its solution.

  19. Cooperative Research Twin Trawl Sweep Comparison Study

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The "Twin-Trawl Sweep Efficiency Study" was intended to compare the sweep efficiency and selectivity of the NEFSC standardized bottom trawl to that of a standardized...

  20. Fish diversity in southern California using trawl data from the National Marine Fisheries Service

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The Shannon Index of diversity was calculated from National Marine Fisheries Service Groundfish Survey Program (NMFS GSP) fish trawl data. Data from 477 fishery...

  1. SEAMAP Groundfish/Shrimp Trawl Red Snapper Analytical Dataset Provided to NRDA

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The Southeast Fisheries Science Center Mississippi Laboratories has conducted standardized groundfish trawl surveys in the Gulf of Mexico since 1987. Prior to 1987,...

  2. Integer-valued trawl processes

    DEFF Research Database (Denmark)

    Barndorff-Nielsen, Ole E.; Lunde, Asger; Shephard, Neil

    2014-01-01

    This paper introduces a new continuous-time framework for modelling serially correlated count and integer-valued data. The key component in our new model is the class of integer-valued trawl processes, which are serially correlated, stationary, infinitely divisible processes. We analyse...... the probabilistic properties of such processes in detail and, in addition, study volatility modulation and multivariate extensions within the new modelling framework. Moreover, we describe how the parameters of a trawl process can be estimated and obtain promising estimation results in our simulation study. Finally...

  3. Performance of pulse trawling compared to conventional beam trawling

    NARCIS (Netherlands)

    Marlen, van B.; Grift, R.E.; Keeken, van O.A.; Ybema, M.S.; Hal, van R.

    2006-01-01

    A series of nine fishing trips with on board observers were carried out on MFV UK153 (PT1) and two beam trawlers (BT1, BT2) of comparative engine power and size to appraise the performance of pulse beam v.s. conventional tickler chain beam trawls. The main conclusions from this study are: 1.

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

    Science.gov (United States)

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

    Directory of Open Access Journals (Sweden)

    Simon J Allen

    Full Text Available 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

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

    Science.gov (United States)

    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

  7. Epibenthic diversity and productivity on a heavily trawled Barents Sea bank (Tromsøflaket

    Directory of Open Access Journals (Sweden)

    Monika Kędra

    2017-04-01

    Full Text Available Shallow Arctic banks have been observed to harbour rich communities of epifaunal organisms, but have not been well-studied with respect to composition or function due to sampling challenges. In order to determine how these banks function in the Barents Sea ecosystem, we used a combination of video and trawl/dredge sampling at several locations on a heavily trawled bank, Tromsøflaket – located at the southwestern entrance to the Barents Sea. We describe components of the benthic community, and calculate secondary production of dominant epifaunal organisms. Forty-six epibenthic taxa were identified, and sponges were a significant part of the surveyed benthic communities. There were differences in diversity and production among areas, mainly related to the intensity of trawling activities. Gamma was the most diverse and productive area, with highest species abundance and biomass. Trawled areas had considerably lower species numbers, and significant differences in epifaunal abundance and biomass were found between all trawled and untrawled areas. Trawling seems to have an impact on the sponge communities: mean individual poriferan biomass was higher in untrawled areas, and, although poriferans were observed in areas subjected to more intensive trawling, they were at least five times less frequent than in untrawled areas.

  8. Impact of bottom trawling on sediment characteristics - A study along inshore waters off Veraval coast, India

    Digital Repository Service at National Institute of Oceanography (India)

    Bhagirathan, U.; Meenakumari, B.; Jayalakshmy, K.V.; Panda, S.K.; Madhu, V.R.; Vaghela, D.T.

    20 ◦ 54 prime 40 primeprime N and longitude 70 ◦ 22 prime 12 primeprime E). Trawling was carried out from CIFT Research vessel MFV Sagarkripa (15.5 m OAL steel stern trawler equipped with 124 hp ALM 412, marine engine), along five transects...

  9. 2013 Joint U.S.-Canada Integrated Acoustic and Trawl Survey of Pacific Hake and Pacific Sardine (SaKe 2015) (SH1507, EK60)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The 2015 SaKe survey will span the west coasts of the U.S. and Canada from approximately lat 32.8?N (San Diego) to approximately lat 54.65?N (Dixon Entrance,...

  10. 2013 Joint U.S.-Canada Integrated Acoustic and Trawl Survey of Pacific Hake and Pacific Sardine (SaKe 2015) (SH1507, ME70)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The 2015 SaKe survey will span the west coasts of the U.S. and Canada from approximately lat 32.8?N (San Diego) to approximately lat 54.65?N (Dixon Entrance,...

  11. Estimating seabed pressure from demersal trawls, seines, and dredges based on gear design and dimensions

    DEFF Research Database (Denmark)

    Eigaard, Ole Ritzau; Bastardie, Francois; Breen, Mike

    2016-01-01

    This study assesses the seabed pressure of towed fishing gears and models the physical impact (area and depth of seabed penetration) from trip-based information of vessel size, gear type, and catch. Traditionally fishing pressures are calculated top-down by making use of large-scale statistics...... such as logbook data. Here, we take a different approach starting from the gear itself (design and dimensions) to estimate the physical interactions with the seabed at the level of the individual fishing operation. We defined 14 distinct towed gear groups in European waters (eight otter trawl groups, three beam...... trawl groups, two demersal seine groups, and one dredge group), for which we established gear “footprints”. The footprint of a gear is defined as the relative contribution from individual larger gear components, such as trawl doors, sweeps, and groundgear, to the total area and severity of the gear...

  12. Towards a trawling-affected sediment budget on the Galician shelf (NW Spain)

    Science.gov (United States)

    Oberle, F. J.; Hanebuth, T. J.

    2013-05-01

    This case study uses vessel monitoring data in conjunction with multiple sedimentological and geochemical proxies on sediment cores to quantify the effect of bottom trawling on a source-to-sink budget analysis of a late Holocene mid-shelf mudbelt. The long-term effect of bottom trawling on seafloor sediments is largely unknown and the existing studies are contradictive. This is particularly surprising as mud depocenters on shelves are of great economic and environmental interest because they represent areas where fishing and other ground disturbing activities have high impacts, and the associated ecosystems hold one of the highest biodiversity. The Galician Mudbelt, exemplary for many other mudbelts worldwide, is located on the open and narrow continental shelf of NW Iberia and is widely affected by chronic (continuous and intensive) commercial bottom trawling. In this study we present the results from 2.800 km of seismo-acoustic data used to calculate a high-resolution isopach map that represents the Late Holocene (Galician shelf. We present here our first calculations. While previous studies show that shelfal mud depocenters represent a major sink for sediments on shelves little is known about the effect trawling has on sediment flux calculations. This study aims to contribute rare quantitative data from a high-energy shelf environment that helps develop a more in depth understanding of the significance of bottom trawling towards material fluxes. Such an analysis may hold serious implications for a better understanding of ecosystem shifts and thus be of economic interest to fisheries.

  13. Using small meshed collecting bags on trawls to quantify trawls seabed disturbance of aquatic organisms

    DEFF Research Database (Denmark)

    Krag, Ludvig Ahm

    of organisms that encounter the trawl, but are not retained by it. Such catch represents an unaccounted trawl disturbance of the organisms associated with the seabed. In combination with knowledge on behavior and habitat utilization of these organisms, their presence can be used to indicate differences...... in the mechanical effect, such as penetration depth of the ground gear of different trawl designs. Collecting bags are also mounted to the different sections of the trawl in pairs, one to collect the organisms that pass through the trawl meshes and one to collect the population. Standard selectivity analyses...... thereby allow us to estimate the size-selection of the caught organisms in different parts of the trawl...

  14. AFSC/ABL: Lynn Canal Overwinter Acoustic Survey, 2004-2005

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The acoustic trawl database for Lynn Canals echo-trawl survey was conducted from 2001 to 2004 throughout southern Lynn Canal in southeast Alaska. Acoustic surveys...

  15. 2014 Small Pelagics Survey (GU1406, EK60)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Objectives of the 2013 Small Pelagics Acoustic/Trawl Survey were to sample the northern Gulf of Mexico with a 90-ft high opening trawl to facilitate assessments of...

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

    Science.gov (United States)

    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.

  17. 33 CFR 150.380 - Under what circumstances may vessels operate within the safety zone or area to be avoided?

    Science.gov (United States)

    2010-07-01

    ... N F C F Fishing, including bottom trawl (shrimping) N D P N Mobile drilling operations or erection...: OPERATIONS Vessel Navigation § 150.380 Under what circumstances may vessels operate within the safety zone or...—Movement of the vessel is permitted when cleared by the person in charge of vessel operations. D—Movement...

  18. A trawl-resistant ocean bottom seismometer

    Science.gov (United States)

    Barclay, A. H.; Gassier, D.; Webb, S. C.; Koczynski, T.; Oletu, V.; Gaherty, J. B.; Tolstoy, M.

    2010-12-01

    Long-term ocean-bottom seismometer (OBS) deployments are difficult on continental shelves and other shallow regions because of the hazard from bottom trawling. Seafloor instruments can be damaged, destroyed, or prematurely released by a trawl net that is weighted with rollers and dragged across the seafloor. Bottom trawling is extensive in many areas and past instrument losses have led the U. S. OBS Instrument Pool (OBSIP) to avoid long-duration deployments in water depths shallower than 1000 m. This restriction is particularly limiting for passive-source seismic studies at active continental margins. We report on the development and testing of a new trawl-resistant OBS. The seismometer and datalogger are protected within a heavy (450 kg) eight-sided steel shield that has a low, smooth profile (2 m basal diameter and a central peak height of 50 cm) and is designed to resist and deflect bottom-trawling equipment. The sides of the shield are closed in order to protect the seismometer from seafloor currents that can cause tilt-related low-frequency seismic noise. Shield-generated noise (from mechanical resonance or from interaction with seafloor currents) is reduced by decoupling the sensor from the shield and by maximizing the distance between the seismometer and the shield’s bottom rim. The heavy weight and low profile of the instrument preclude the use of dropweights for deployment and recovery. The OBS is instead lowered to the seafloor and recovered by attaching a lifting line using a remotely-operated vehicle. Twenty trawl-resistant OBSs, equipped with Trillium Compact seismometers and absolute pressure gauges, are being constructed and will be deployed as a component of the NSF Cascadia Initiative in the summer of 2011.

  19. Collecting marine litter during regular fish surveys

    NARCIS (Netherlands)

    Sluis, van der M.T.; Hal, van R.

    2014-01-01

    This report presents the results of the marine litter monitoring on the IBTS survey of 2014 and the BTS survey of 2013. Since 2013 marine litter is collected during the International Bottom Trawl Survey (IBTS) and Dutch Beam Trawl Survey (BTS) following a protocol developed by ICES. The composition

  20. Selective haddock (Melanogrammus aeglefinus) trawling: Avoiding cod (Gadus morhua) bycatch

    DEFF Research Database (Denmark)

    Krag, Ludvig Ahm; Holst, René; Madsen, Niels

    2010-01-01

    a selective trawl based on the behavioral differences between haddock and cod as they enter a trawl, i.e., cod stay close to the seabed whereas haddock rise above it. The trawl's fishing line is raised similar to 60 cm above the seabed to allow cod to escape beneath the trawl while haddock are retained....... To collect the escapees, three sampling bags were attached beneath the raised fishing line. The selective haddock trawl reduced the total catch of cod by 55% during the day and 82% at night, and 99% of the marketable haddock was caught during the day and 89% at night. Cod escape rates were highly length...

  1. Net escapement of Antartic krill in trawls

    DEFF Research Database (Denmark)

    Krafft, B.A.; Krag, Ludvig Ahm; Herrmann, Bent

    This document describes the aims and methodology of a three year project (commenced in 2012) entitled Net Escapement of Antarctic krill in Trawls (NEAT). The study will include a morphology based mathematical modeling (FISHSELECT) of different sex and maturity groups of Antarctic krill (Euphausia...

  2. (LSMTPC) trawl codends for blue whiting (Micromesistius

    African Journals Online (AJOL)

    Administrator

    2010-12-27

    2009) for the map of the study area). Towing duration varied between 90 and 300 min, and towing speed change was between 2.2 and 2.3 knots. The trawl was a .... crustacean fishery off the Portuguese south coast. Fish. Res.

  3. Fishing effects in northeast Atlantic shelf seas : patterns in fishing effort, diversity and community structure. III. International trawling effort in the North Sea : an analysis of spatial and temporal trends

    DEFF Research Database (Denmark)

    Jennings, S.; Alsväg, J.; Cotter, A.J.R.

    1999-01-01

    This paper describes trends in beam and otter trawling effort in the North Sea from 1977 to 1995, Data are presented as total hours fishing by English, German, Norwegian, Scottish and Welsh vessels for the period 1977-1995, and by Danish, Dutch, English, German, Norwegian, Scottish and Welsh...... vessels for the period 1990-1995. Analyses of temporal trends indicated that total international trawling effort in the entire North Sea has increased slowly since 1977 and that it is currently (1995) 2.25 million h yr(-1) of which 55% is due to beam trawling, Spatial analyses indicate that the proportion...... of beam trawling effort increases from north to south. Plots of annual fishing effort by ICES statistical rectangle (211 boxes of 0.5 degrees latitude x 1 degrees longitude) indicate that the majority of fishing effort in the North Sea are concentrated in a very few rectangles. Thus mean annual total...

  4. Trawling on seamounts: can we balance exploitation and conservation?

    Science.gov (United States)

    Clark, M. R.; O'Driscoll, R. L.; Rowden, A. A.

    2006-12-01

    Seamounts are prominent features of the worlds underwater topography. They are widely regarded as productive, but fragile, habitat. They are the focus of commercial fishing for a number of demersal and pelagic fish and invertebrate species. Most fishing operations have some impact, either on the target species, associated bycatch species, or the benthic communities and habitat. Longlines, gillnets, traps and pots can all have some effect on the seafloor, but bottom trawling is the most well-known for causing considerable impact on the benthic habitat. There are few published studies on seamounts specifically, and recent research in New Zealand will be described. This has focused on deepwater fisheries for species such as orange roughy, which can form large aggregations over seamount features. The research includes analysis of the distribution of commercial catch and effort data from deepwater seamount fisheries, and "compare and contrast" surveys of seamounts that indicate the effects of bottom trawling can be severe on benthic invertebrate fauna. Fishing has clear consequences for structural complexity of the benthic habitat, and can alter species composition, and abundance. The results of such research are discussed with respect to management of seamount habitat in New Zealand, and the search for a balance that can allow sustainable seamount fisheries, and biodiversity conservation.

  5. Fishing effects in northeast Atlantic shelf seas: patterns in fishing effort, diversity and community structure. III. International trawling effort in the North Sea: an analysis of spatial and temporal trends

    NARCIS (Netherlands)

    Jennings, S.; Alvsvag, J.; Cotter, A.J.R.; Ehrich, S.; Greenstreet, S.P.R.; Jarre-Teichmann, A.; Mergardt, N.; Rijnsdorp, A.D.; Smedstad, O.

    1999-01-01

    This paper describes trends in beam and otter trawling effort in the North Sea from 1977 to 1995. Data are presented as total hours fishing by English, German, Norwegian, Scottish and Welsh vessels for the period 1977-1995, and by Danish, Dutch, English, German, Norwegian, Scottish and Welsh vessels

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

    Science.gov (United States)

    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 (multiple regression (DISTLM) models. Species richness was highest at intermediate depths and in areas subject to intermediate levels of trawling, and higher under hypoxia than under severe hypoxia. These statistically significant trends demonstrate that the structuring influences of bottom trawling on deep-sea benthic communities can be observed even where communities are being shaped by strong environmental gradients.

  7. Challenges in licensing the industrial double-rig trawl fisheries in Brazil

    Directory of Open Access Journals (Sweden)

    Paulo Ricardo-Pezzuto

    2015-07-01

    Full Text Available Bottom trawling is important in Brazilian fisheries and is currently highly multi-specific due to the overexploitation of the original targets; unselective fishing method; very large permitted fishing area and the country's high marine biodiversity. Fishing licensing in Brazil was modified in 2012 and is now based in five criteria: target species; "expected by-catch"; "incidental catches"; fishing method and area of operation. Licenses of trawling fleets exhibit, therefore, dozens of species catchable under the first three criteria. In this paper, we analyze industrial double-rig trawling fleets targeting shrimps and demersal fishes, in order to verify in what extent the new system adhere to the current fishing reality, giving new information to improve the current management regime. A total of 4,194 trips from 191 vessels were studied between 2008 and 2010 in southern Brazil. In spite of depending economically on their targets, the fleets are formally authorized to catch a high percentage of species in common (41 to 71%, and the actual landings revealed an even greater overlapping among them (71 to 82%. Vessels licensed to catch demersal fishes obtained nearly 50% of their revenue from items not included in their licenses. It was concluded that the current system encourages excessive effort concentrations over fishing resources, as they can be legally caught by most vessels irrespective of their licenses. It is suggested that licensing should move from a species-based to a spatial-based approach, by defining smaller management areas according to the respective species assemblages. Landing composition would be, therefore, mostly a biological and technological consequence, making management more reasonable and workable under a multi-specific and mega-diverse scenario.

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

    Science.gov (United States)

    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

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

    Directory of Open Access Journals (Sweden)

    Philip Francis Thomsen

    Full Text Available 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

  10. Fish species, Fish biomass, Fishery survey, invertebrate species, and other variables collected from midwater net tows, and bottom trawl observations using net, trawl, and other instruments from the Arctic Ocean, and Beaufort Sea from August 6, 2008 to August 21, 2008 (NODC Accession 0112823)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The Alaska Fisheries Science Center's Status of Stocks and Multispecies Assessment (SSMA) Programs Fishery Interaction Team (FIT) conducted a fish survey in the...

  11. Estimating species and size composition of rockfishes to verify targets in acoustic surveys of untrawlable areas

    OpenAIRE

    Rooper, Christopher N.; Martin, Michael H.; Butler, John L.; Jones, Darin T.; Zimmermann, Mark

    2012-01-01

    Rockfish (Sebastes spp.) biomass is difficult to assess with standard bottom trawl or acoustic surveys because of their propensity to aggregate near the seafloor in highrelief areas that are inaccessible to sampling by trawling. We compared the ability of a remotely operated vehicle (ROV), a modified bottom trawl, and a stereo drop camera system (SDC) to identify rockfish species and estimate their size composition. The ability to discriminate species was highest for the bottom trawl...

  12. Survey gear calibration independent of spatial fish distribution

    DEFF Research Database (Denmark)

    Lewy, Peter; Nielsen, J. Rasmus; Hovgård, Holger

    2004-01-01

    Trawl surveys provide important information for evaluation of relative stock abundance fluctuations over time. Therefore, when survey gears or vessels are changed, it is important to compare the efficiency and selectivity of old and new gears and vessels. A method for estimation of conversion...... and disturbance parameters with their precision are obtained using standard software. Simulation studies carried out additionally showed that the estimated conversion factors were practically unbiased. Because of the independence of the spatial fish distribution, the new method is preferable to the traditional...... paired hauls design for which it is generally not possible to obtain the statistical properties of the estimated conversion factors. The paper is concluded with suggestions on how to optimize survey design. The method was used to estimate conversion factors for Atlantic cod (Gadus morhua) from Danish...

  13. NEFSC Survey Indices of Abundance

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Northeast Fisheries Survey Bottom trawl survey indices of abundance such as stratified mean number per tow or mean weight per tow by species stock. Includes indices...

  14. Catch and discardfish species of trawl fisheries in the Iskenderun Bay (Northeastern Mediterranean with emphasis on lessepsian and chondricthyan species

    Directory of Open Access Journals (Sweden)

    E. YEMISKEN

    2014-04-01

    Full Text Available Fish species in catch and discard of trawl fisheries in and around Iskenderun Bay were examined within the fishing closure period and fishingperiod.The sampling was performed from May 2010 to January 2011 by a commercial trawl vessel.Chondricthyan species composed 49 % of discard catch biomass whileGymnura altavela and Dasyatis pastinacawere dominant in hauls. 27 lessepsian fish species were captured during the study,nine of them beingtarget species for trawl fisheries. In total, 14 of the lessepsian fish species were determined as discard species.In both sampling periods, Equulites klunzingeriand Citharus linguatula contributed to discard fish catch dissimilarity among depth ranges (deeper and shallower than 60 m. E. klunzingerishowed high abundance in discard catch.There were no significant differences in the distribution of the discard fish biomass between the sampling periods (ANOVA test, p>0.05. However, depth range pointed out significantdifferences in discard fish catch composition (p<0.05.Among major commercial fish species of trawl fisheries, Mullus surmuletus and Sparus aurata were not separated as discard in anyhaul by fishermen. Any size of these two species  were included in commercial catch (Total length ranged from 61 to 721 mm.

  15. Industry Based Monkfish Survey

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Monkfish industry leaders expressed concerns that the NEFSC bottom trawl surveys did not sample in all monkfish habitats; particularly the deeper water outside the...

  16. Hake Survey ADCP (2005)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Shipboard acoustic Doppler current profiler data collected during the Integrated Acoustic and Trawl Surveys of Pacific Hake. Processing by: Stephen Pierce, Oregon...

  17. Hake Survey ADCP (1998)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Shipboard acoustic Doppler current profiler data collected during the Integrated Acoustic and Trawl Surveys of Pacific Hake. Processing by: Stephen Pierce, Oregon...

  18. Hake Survey ADCP (2003)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Shipboard acoustic Doppler current profiler data collected during the Integrated Acoustic and Trawl Surveys of Pacific Hake. Processing by: Stephen Pierce, Oregon...

  19. Hake Survey ADCP (2001)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Shipboard acoustic Doppler current profiler data collected during the Integrated Acoustic and Trawl Surveys of Pacific Hake. Processing by: Stephen Pierce, Oregon...

  20. Hake Survey ADCP (1995)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Shipboard acoustic Doppler current profiler data collected during the Integrated Acoustic and Trawl Surveys of Pacific Hake. Processing by: Stephen Pierce, Oregon...

  1. Atlantic Herring Acoustic Surveys

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The NEFSC Advanced Sampling Technologies Research Group conducts annual fisheries acoustic surveys using state-of-the-art acoustic, midwater trawling, and underwater...

  2. Deep Water Survey Data

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The deep water biodiversity surveys explore and describe the biodiversity of the bathy- and bentho-pelagic nekton using Midwater and bottom trawls centered in the...

  3. DIAGNOSIS OF SHRIMP TRAWLING IN THE STATE OF PERNAMBUCO, BRAZIL

    Directory of Open Access Journals (Sweden)

    Carlos Eduardo Rangel Andrade

    2016-09-01

    Full Text Available With a technical approach, this diagnosis aims to fill a gap in the overview of the activity, considering its technical aspects that manage the fishing effort of shrimping of Penambuco. From October 2013 to August 2014, the fishing grounds were identified used in this activity, as well as the fishing method, the number of boats and fishermen acting, type of boat and gears used. Analyses were performed with the major communities operating in this fishery (Recife, Jaboatão dos Guararapes, Barra de Sirinhaém and São Jose da Coroa Grande. The analyzes of the catch were tested using one-way ANOVA (α 5%. They observed two traditional types: the beach seining and trawing. It was cataloged about 50 vessels in the activity, with approximately 100 fishermen. They are caught mainly three types of shrimp: pink (Farfantepenaeus spp., Seabob (Xiphopenaeus kroyeri and white (Lithopenaeus schmitii. Statistical data concentrated in the metropolitan area of Recife and Barra de Sirinhaém. There seems to be a direct relationship rainfall with shrimp production because with increased rainfall, there is a higher volume of landing fishery. Barra de Sirinhaém is the main area used in the State. Keywords: ‘mangote’; trawling fishing; pink shrimp; Farfantepenaeus spp.

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

    DEFF Research Database (Denmark)

    Krag, Ludvig Ahm; Herrmann, Bent; Iversen, Svein A.

    2014-01-01

    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...... and results described are important tools for selecting optimal trawl designs for krill fishing....

  5. Reduction of discards by technical modifications of beam trawls

    NARCIS (Netherlands)

    Marlen, van B.; Helmond, van A.T.M.; Buyvoets, E.

    2009-01-01

    Experiments were carried out in 2007 and 2008 on discard reducing techniques in flatfish beam trawling onboard FRV “Tridens” in close cooperation with the fishing industry. A total of 38 gear tests were conducted in which modified beam trawls were compared in pair with a conventional 12 m beam

  6. Vessel Operating Units (Vessels)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This data set contains data for vessels that are greater than five net tons and have a current US Coast Guard documentation number. Beginning in1979, the NMFS...

  7. Methods for integrated use of fisheries research survey information in understanding marine fish population ecology and better management advice : improving methods for evaluation of research survey information under consideration of survey fish detection and catch efficiency

    NARCIS (Netherlands)

    Nielsen, J.R.

    2015-01-01

    Summary The thesis developed and improved methods for the integrated analysis of different types of fishery independent research surveys (trawl surveys, acoustic surveys, hydrographical surveys, and gillnet surveys) to study the distribution, density, abundance, migration and

  8. For-Hire Vessel Directory

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The Vessel Directory is maintained as the sample frame for the For-Hire Survey. I contains data on for-hire vessels on the Atlantic and Gulf coasts. Data include...

  9. Wreckfish Logbook Survey (Vessels)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Federally managed fisheries that currently have mandatory logbook and bycatch reporting requirements for the Southeast Region include snapper/grouper/wreckfish....

  10. Environmental DNA from seawater samples correlate with trawl catches of Subarctic, deepwater fishes

    DEFF Research Database (Denmark)

    Thomsen, Philip Francis; Møller, Peter Rask; Sigsgaard, Eva Egelyng

    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 bo......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...

  11. Fishery survey, benthic organism, and zooplankton data collected using trawls and tows from the EASTWARD and other platforms in the North Atlantic Ocean and Others from 1980-01-16 to 1984-03-14 (NODC Accession 8500245)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Fishery survey, fishing duration and other benthic organism data from unknown and other platforms from North Atlantic Ocean was collected over four years between...

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

    Directory of Open Access Journals (Sweden)

    Melanie J Underwood

    Full Text Available 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.

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

    Science.gov (United States)

    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.

  14. 77 FR 29586 - Sea Turtle Conservation; Shrimp Trawling Requirements; Correction

    Science.gov (United States)

    2012-05-18

    ... Part 223 RIN 0648-BC10 Sea Turtle Conservation; Shrimp Trawling Requirements; Correction AGENCY... turtle excluder devices (TEDs) in their nets, and announced five public hearings to be held in Morehead...

  15. Gear Selectivity of a Longfin Squid Bottom Trawl

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Loligo pealeii (longfin inshore squid) co-occurs with Atlantic butterfish (Peprilus triacanthus) throughout the year and discarding in the L. pealeii bottom trawl...

  16. Corpus Christi EFH Trawling Effects 2001-2002

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — We compared sediments and benthos of two adjacent zones of the middle Texas coast, one of which was closed to shrimp trawling for 7 months. Findings indicated that...

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

    Science.gov (United States)

    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.

  18. CTD data - Pre-recruit surveys to aid stock assessment

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Annual surveys of juvenile fish and ecosystem status have been conducted since 2011 surveying the entire coast of Oregon and southern Washington. Trawl surveys are...

  19. Temperature and salinity profile data from CTD casts from NOAA Survey Vessel BAY HYDROGRAPHER during the 2007 field season in the NW Atlantic from 05 February 2007 to 06 February 2008 (NODC Accession 0039241)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Physical oceanographic data were collected from the NOAA Survey Vessel BAY HYDROGRAPHER in the NW Atlantic from 05 February 2007 to 06 February 2008. Data were...

  20. Interactions between a Trawl fishery and spatial closures for biodiversity conservation in the Great Barrier Reef World Heritage Area, Australia.

    Science.gov (United States)

    Grech, Alana; Coles, Rob

    2011-01-01

    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. 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. 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.

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

    Science.gov (United States)

    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

  2. Interactions between a Trawl fishery and spatial closures for biodiversity conservation in the Great Barrier Reef World Heritage Area, Australia.

    Directory of Open Access Journals (Sweden)

    Alana Grech

    Full Text Available 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.

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

    Science.gov (United States)

    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.

  4. Long-term effects of bottom trawling on large sponges in the Gulf of Alaska

    Science.gov (United States)

    Malecha, Patrick; Heifetz, Jonathan

    2017-11-01

    Manipulative studies that characterize short-term effects of bottom trawls on seafloor habitats are numerous, but studies that examine long-term effects are rare. The long-term (13 years) effects of a single bottom trawl on large (>20 cm) erect sponges were investigated by revisiting the site of prior experimental trawling studies. In prior studies, large sponges were assessed immediately after trawling and 1 yr post-trawling. Thirteen years post-trawling, the average density of large sponges was 31.7% lower (range 1.5-53.0%) and the incidence of sponge damage (torn, necrotic, missing tissue, prone) was 58.8% higher within strip transects in trawled versus untrawled reference areas. For all sponge species combined, the mean density of large sponges was 3.19 individuals 100 m-2 in trawled areas and 4.67 individuals 100 m-2 in reference areas. The most abundant sponge species in both trawled and reference areas was Rhabdocalyptus dawsoni. Mean density of this species differed greatly between trawled (1.57 individuals 100 m-2) and reference areas (2.91 individuals 100 m-2). Thirteen years after trawling, the mean percentage of damaged sponges on strip transects was 15.3% in trawled areas and 6.3% in reference areas. The rate of damage in trawled areas was less than that observed both immediately after trawling and 1 year later. The persistence of damage (lower sponge densities and higher rates of injury in trawled areas) and the potential resultant changes to benthic communities where deepwater habitat-forming biota, such as large erect sponges, are present provide rationale for cautious management of the long term effects of bottom trawling.

  5. Estimation of seafloor impact from demersal trawls, seines and dredges based on gear design and dimensions

    DEFF Research Database (Denmark)

    Eigaard, Ole Ritzau; Bastardie, Francois; Breen, Michael

    otter trawl groups, 3 beam trawl groups, 2 demersal seine groups, and 1 dredge group), for which we established seafloor “footprints”. The footprint of a gear was defined as the relative contribution from individual larger gear components, such as the trawl doors, sweeps and ground gear, to the total...

  6. Stable isotopes reveal the effect of trawl fisheries on the diet of commercially exploited species

    DEFF Research Database (Denmark)

    Hinz, Hilmar; Moranta, Joan; Balestrini, Stephen

    2017-01-01

    Bottom trawling can change food availability for benthivorous demersal species by (i) changing benthic prey composition through physical seabed impacts and (ii) by removing overall benthic consumer biomass increasing the net availability of benthic prey for remaining individuals. Thus trawling ma...... that the removal of demersal competitors and benthos by trawling can change the diets of commercial species, ultimately affecting their body condition....

  7. Development and test of Dyneema shrimp trawl; Udvikling og forsoeg med dyneema rejetrawl

    Energy Technology Data Exchange (ETDEWEB)

    Hansen, K.

    1999-01-01

    This report describes the results from analysis of test fishing with one shrimp trawl made of standard materials and one shrimp trawl made of the material Dyneema, which is stronger than the standard material. By using the new developed trawl savings of 43 l fuel/hour is obtained. (EHS)

  8. Modeling the impacts of bottom trawling and the subsequent recovery rates of sponges and corals in the Aleutian Islands, Alaska

    Science.gov (United States)

    Rooper, Christopher N.; Wilkins, Mark E.; Rose, Craig S.; Coon, Catherine

    2011-11-01

    The abundance of some marine fish species are correlated to the abundance of habitat-forming benthic organisms such as sponges and corals. A concern for fisheries management agencies is the recovery of these benthic invertebrates from removal or mortality from bottom trawling and other commercial fisheries activities. Using a logistic model, observations of available substrate and data from bottom trawl surveys of the Aleutian Islands, Alaska, we estimated recovery rates of sponges and corals following removal. The model predicted the observed sponge and coral catch in bottom trawl surveys relatively accurately ( R2=0.38 and 0.46). For sponges, the results show that intrinsic growth rates were slow ( r=0.107 yr -1). Results show that intrinsic growth rates of corals were also slow ( r=0.062 yr -1). The best models for corals and sponges were models that did not include the impacts of commercial fishing removals. Subsequent recovery times for both taxa were also predicted to be slow. Mortality of 67% of the initial sponge biomass would recover to 80% of the original biomass after 20 years, while mortality of 67% of the coral biomass would recover to 80% of the original biomass after 34 years. The modeled recovery times were consistent with previous studies in estimating that recovery times were of the order of decades, however improved data from directed studies would no doubt improve parameter estimates and reduce the uncertainty in the model results. Given their role as a major ecosystem component and potential habitat for marine fish, damage and removal of sponges and corals must be considered when estimating the impacts of commercial bottom trawling on the seafloor.

  9. Ecosystems Surveys Branch Gear Efficiency Study

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — An experiment aimed at quantifying the herding efficiency of flatfish for the Northeast Fisheries Science Center (NEFSC) survey trawl bridles was conducted during...

  10. NEFSC 1999 Spring Bottom Trawl Survey (AL9903, EK500)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The objectives of the cruise are to: (1) determine the spring distribution and relative abundance of fish and selected invertebrate species; (2) collect biological...

  11. NEFSC 2001 Spring Bottom Trawl Survey (AL0104, EK500)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The objectives of the cruise are to: (1) determine the spring distribution and relative abundance of fish and selected invertebrate species; (2) collect biological...

  12. Precision in systematic trawl surveys as assessed from replicate ...

    African Journals Online (AJOL)

    African Journal of Marine Science. Journal Home · ABOUT THIS JOURNAL · Advanced Search · Current Issue · Archives · Journal Home > Vol 23 (2001) >. Log in or Register to get access to full text downloads.

  13. NEFSC 2001 Winter Bottom Trawl Survey (AL0102, EK500)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The objectives of the cruise are to: (1) determine the winter distribution and relative abundance of fish and selected invertebrate species; (2) collect biological...

  14. NEFSC 1999 Winter Bottom Trawl Survey (AL9902, EK500)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The objectives of the cruise are to: (1) determine the winter distribution and relative abundance of fish and selected invertebrate species; (2) collect biological...

  15. NEFSC 2000 Spring Bottom Trawl Survey (AL0002, EK500)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The objectives of the cruise are to: (1) determine the spring distribution and relative abundance of fish and selected invertebrate species; (2) collect biological...

  16. NEFSC 2000 Winter Bottom Trawl Survey (AL0001, EK500)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The objectives of the cruise are to: (1) determine the winter distribution and relative abundance of fish and selected invertebrate species; (2) collect biological...

  17. Sea floor litter monitoring : International Bottom Trawl Survey 2016

    NARCIS (Netherlands)

    Hal, van Ralf

    2017-01-01

    The Marine Strategy Framework Directive (MSFD) requires the European Member States to develop programmes of measures to achieve or maintain Good Environmental Status (GES) in European Seas. To be able to evaluate the quality state of the marine waters on a regular basis and the effect of measures

  18. NEFSC 2001 Spring Bottom Trawl Survey (AL0103, EK500)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The objectives of the cruise are to: (1) determine the spring distribution and relative abundance of fish and selected invertebrate species; (2) collect biological...

  19. Aerial Survey of Vessel Usage and Marine Animal Occurrence between Ft. Pierce and Key West Florida, 1992-2004

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — An aerial survey between Ft Pierce and Key West Florida was performed aboard US Coast Guard helicopters and fixed wing aircraft from September 1992 through March...

  20. Fish Catch Composition of Artisanal and Bottom Trawl Fisheries in ...

    African Journals Online (AJOL)

    Africa; 4Gent University, Marine Biology Research Group, Krijgslaan 281 – S8, 9000,. Gent, Belgium; 5Technical University of Mombasa, Department of Environment and Health. Sciences, Marine Sciences Section, PO Box 90420, 80100 Mombasa, Kenya. Keywords: Trawl bycatch, artisanal catch, catch composition, ...

  1. Monitoring of cod catches in Dutch otter trawls and seines

    NARCIS (Netherlands)

    Kraan, M.L.; Uhlmann, S.S.; Machiels, M.A.M.; Overzee, van H.M.J.; Helmond, van A.T.M.

    2013-01-01

    This report presents the results of the Dutch Cod Monitoring Project in the bottom trawls and seines (TR), that was carried out in 2011 and 2012. The monitoring project was set up to monitor the cod catches in the different TR gears in order to have better and more detailed information of the catch

  2. Decision Support to Sustainable Management of Bottom Trawl Fleet

    Directory of Open Access Journals (Sweden)

    Irena Bitunjac

    2016-03-01

    Full Text Available A decision support concept (DSC for sustainable management of the bottom trawl fleet was created in line with ecosystem-based management. It is based on principles that integrate ecological, social and techno-economic aspects of trawl fisheries in a multicriteria analysis approach. For the sake of greater transparency and improved stakeholder participation, elements of the proposed multicriteria models were discussed, generated and evaluated in collaboration with designated experts from four stakeholder groups: fishers, environmentally focused non-governmental organizations, fisheries scientists and government representatives. The proposed DSC management could facilitate management and assist decision makers in adequately using data and scientific advice to shape management strategies and related policies for the bottom trawl fleet. It may also assist in finding compromise solutions based on deliverables from the multicriteria analysis, while taking stakeholder requirements into account by using the multicriteria Analytic Hierarchy Process (AHP and Preference Ranking Organization Method for Enrichment Evaluations (PROMETHEE methods. The final decision is then based on a vast amount of knowledge and relevant information collected from different sources. The proposed DSC represents a novel approach to fishery fleet management and assists in systematizing management processes and instruments to make it operational at the strategic level. The method was applied to the Adriatic bottom trawl fishery, and the obtained results confirmed its managerial potential in the strategic decision-making process, aimed at improving conventional management, while considering the specific requirements of an ecosystem-based approach and ensuring stakeholder participation.

  3. Fish Catch Composition of Artisanal and Bottom Trawl Fisheries in ...

    African Journals Online (AJOL)

    sampled to compare fish species composition and abundance according to area. (inshore; offshore) and season (northeast monsoon - NEM, southeast monsoon -. SEM) and identify the species contributing most to catch overlap. The diversity of fish catches was greater in trawl (223 species) than artisanal samples (177) in ...

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

    Science.gov (United States)

    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…

  5. Job Satisfaction in the Shrimp Trawl Fisheries of Vietnam

    Science.gov (United States)

    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…

  6. Effect of bottom type on catch rates of North Sea cod (Gadus morhua) in surveys with commercial fishing vessels

    DEFF Research Database (Denmark)

    Wieland, Kai; Pedersen, Eva Maria; Olesen, Hans Jakob

    2009-01-01

    were substantially higher on gravel or stone bottom and at ship wrecks than on sand bottom. The difference in the catch rates between the two bottom categories at paired stations within a short distance was highly significant for all the three fishing methods. Similarly, average CPUE for most surveys...

  7. Determination of effective effort on hake Merluccius merluccius in a Mediterranean trawl fishery

    Directory of Open Access Journals (Sweden)

    Francisco Alemany

    2003-12-01

    Full Text Available The direct control of fishing effort as a management tool is of special interest in the Mediterranean, where the lack of effective international management systems and the high diversity of the catches significantly increases the complexity of implementing TAC´s as an indirect control of fishing effort. However, its enforcement should be based on the precise knowledge of the relationship between the fishing effort and its corresponding fishing mortality. In this sense, the general aim of this study was to develop an approach for analysing this relationship. In order to estimate the annual effective fishing effort on hake, a relational data base including daily landings by vessel and species of trawl fleet based on the port of Palma, Mallorca island (western Mediterranean during the period 1983-1991 was built. Fishing mortalities were available from VPA. Fishing effort and fishing mortality were split by subfleets or métiers which were identified by cluster analysis. Significant linear relationships between the two parameters were obtained when fishing effort was considered as the number of days in which hake catch was higher than 10 kg multiplied by GRT of correspondent vessels. These CPUE values are mainly obtained when trawlers operate in the muddy bottoms of the shelf and on the upper slope, where hake populations are mostly distributed. On the other hand, no clear trends in catchability by métier were found during the period analysed.

  8. Research vessels

    Digital Repository Service at National Institute of Oceanography (India)

    Rao, P.S.

    by the research vessels RV Gaveshani and ORV Sagar Kanya are reported. The work carried out by the three charted ships is also recorded. A short note on cruise plans for the study of ferromanganese nodules is added...

  9. CPS Trawl Life History Haul Catch Data

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Weight in kilograms for all species (identified to lowest taxonomic criteria) caught during SWFSC-FRD fishery independent surveys (including DEPM, ATM, SaKe) of...

  10. Assessment of the cover effect in trawl codend selectivity experiments

    DEFF Research Database (Denmark)

    Madsen, Niels; Holst, René

    2002-01-01

    The covered codend technique is widely used to estimate codend selectivity Curves. The codend cover may, however, influence the codend selectivity. In this experiment, a codend fitted with a square mesh window and surrounded by a cover was tested against a similar uncovered codend in a twin trawl...... rig in the Baltic cod fishery. Kites were attached to the cover to maintain a,good clearance from the codend meshes. The analysis of the data followed the general SELECT approach adapted to fit the particular conditions of the experiment. Selection curves for the two codends were fitted simultaneously...... to the catch data and compared. The selectivity of the codend with cover was determined by the covered codend method and that of the uncovered codend effectively determined by the twin trawl method. It was estimated that 21% fewer cod entered the codend with cover than the codend without cover. The estimated...

  11. Modelling potential impacts of bottom trawl fisheries on soft sediment biogeochemistry in the North Sea†

    Directory of Open Access Journals (Sweden)

    Parker Ruth

    2001-12-01

    Full Text Available Bottom trawling causes physical disturbance to sediments particularly in shelf areas. The disturbance due to trawling is most significant in deeper areas with softer sediments where levels of natural disturbance due to wave and tidal action are low. In heavily fished areas, trawls may impact the same area of seabed more than four times per year. A single pass of a beam trawl, the heaviest gear routinely used in shelf sea fisheries, can kill 5–65% of the resident fauna and mix the top few cm of sediment. We expect that sediment community function, carbon mineralisation and biogeochemical fluxes will be strongly affected by trawling activity because the physical effects of trawling are equivalent to those of an extreme bioturbator, and yet, unlike bioturbating macrofauna, trawling does not directly contribute to community metabolism. We used an existing box-model of a generalised soft sediment system to examine the effects of trawling disturbance on carbon mineralisation and chemical concentrations. We contrasted the effects of a natural scenario, where bioturbation is a function of macrobenthos biomass, with an anthropogenic impact scenario where physical disturbance results from trawling rather than the action of bioturbating macrofauna. Simulation results suggest that the effects of low levels of trawling disturbance will be similar to those of natural bioturbators but that high levels of trawling disturbance prevent the modelled system from reaching equilibrium due to large carbon fluxes between oxic and anoxic carbon compartments. The presence of macrobenthos in the natural disturbance scenario allowed sediment chemical storage and fluxes to reach equilibrium. This is because the macrobenthos are important carbon consumers in the system whose presence reduces the magnitude of available carbon fluxes. In soft sediment systems, where the level physical disturbance due to waves and tides is low, model results suggest that intensive trawling

  12. Distribution and abundance of the argentinean (Artemesia longinaris) and the red prawns (Pleoticus muelleri) (Decapoda:Penaeoidea) in Southern Brazil during the commercial double-rig trawl fishery season

    OpenAIRE

    Dumont, Luiz Felipe Cestari; D’Incao, Fernando

    2008-01-01

    Declining in landings of more valuable prawn species, such as pink prawns(Farfantepenaeus paulensis and F. brasiliensis), expanded the targets of double-rig ottertrawlers to other species such as Artemesia longinaris and Pleoticus muelleri. In attempting to increase information on distribution and abundance of these prawns, 64 samples were analyzed in summer/2005 during the commercial trawling fishery season off Rio Grande do Sul coast. Samples were collected from a research vessel (NOc...

  13. The comparative statuses of the Far Eastern seas and the northwestern Pacific Ocean based on the range of integral characteristics of pelagic and bottom trawl macrofauna

    Directory of Open Access Journals (Sweden)

    Igor V. Volvenko

    2015-03-01

    Full Text Available Comparison of the pelagial and benthal of the Far Eastern seas (mainly within the borders of the Russian EEZ and the contiguous part of the Pacific Ocean according to the macrofauna population density, species richness, evenness and diversity, and average individual weight of animals, is provided on the basis of the results of multiannual broad-scale pelagic and bottom trawl surveys carried out in 1977–2010.

  14. Fish bycatch of the laulao catfish Brachyplatystoma vaillantii (Valenciennes, 1840 trawl fishery in the Amazon Estuary

    Directory of Open Access Journals (Sweden)

    Erica Antunes Jimenez

    2013-06-01

    Full Text Available This study aimed to analyse the composition and seasonal variation in the fish bycatch of the Brachyplatystoma vaillantii trawl fishery in the Amazon Estuary in 2009 by monitoring the trips of 48 vessels. The bycatch represented 29% of the catches, totalling 22,228 specimens and 52 taxa, distributed in 22 families (the principal families were Ariidae, Pimelodidae, and Sciaenidae. Brachyplatystoma rousseauxii, Plagioscion squamosissimus, and Sciades herzbergii together contributed 69% of the bycatch and were considered consistent bycatch species. Although a higher proportion of bycatch was captured during the rainy season, the seasonal difference was not significant. A multidimensional scaling (MDS ordination analysis and an analysis of similarity (ANOSIM indicated that the species composition of the bycatch was similar across the seasons. However, larger numbers of B. rousseauxii and P. squamosissimus were captured during the rainy season, whereas S. herzbergii predominated during the dry season. The marine migrants and estuarine species guilds showed the greatest richness, whereas freshwater migrants were the most numerous. Among the feeding guilds, the zoobenthivores were the most diverse, whereas the piscivores were the most abundant. The results indicate that fishing pressure primarily affects small- (20-30 cm and medium-sized (30-50 cm individuals, although the catch of P. squamosissimus was composed primarily of adults. However, the catches of both B. rousseauxii and B. vaillantii were composed primarily of juveniles.

  15. Gadoids per hour caught by demersal trawl in the North Sea

    NARCIS (Netherlands)

    Beare, D.J.; Helmond, van A.T.M.

    2009-01-01

    In this project we summarise the numbers of gadoids landed by the Dutch beam trawl and otter trawl fleet in 2007 and 2008. We then make the best estimates possible of discarded numbers using data from the Discard Sampling Programme. These data will be used in negotiations between Norway and the EU

  16. Effects of chronic bottom trawling on soft-seafloor macrofauna in the Kattegat

    DEFF Research Database (Denmark)

    Sköld, Mattias; Göransson, Peter; Jonsson, Patrik

    2018-01-01

    Impact studies of chronic bottom trawling aiming to reveal long-term effects on benthic organisms are often hampered by the lack of comparable untrawled conditions and the difficulty in assessing the spatial distribution of trawling intensity. We sampled soft-seafloor macrofauna over a precise tr...

  17. FLEXSELECT: counter-herding device to reduce bycatch in crustacean trawl fisheries

    DEFF Research Database (Denmark)

    Melli, Valentina; Karlsen, Junita Diana; Feekings, Jordan P.

    2017-01-01

    FLEXSELECT is a simple counter-herding device which aims at reducing the bycatch of fish by scaring them away from the trawl path without affecting the catches of the target species. FLEXSELECT was tested in the Norway lobster (Nephrops norvegicus) directed trawl fishery, as this includes bycatch...

  18. Stable isotopes reveal the effect of trawl fisheries on the diet of commercially exploited species.

    Science.gov (United States)

    Hinz, Hilmar; Moranta, Joan; Balestrini, Stephen; Sciberras, Marija; Pantin, Julia R; Monnington, James; Zalewski, Alex; Kaiser, Michel J; Sköld, Mattias; Jonsson, Patrik; Bastardie, Francois; Hiddink, Jan Geert

    2017-07-24

    Bottom trawling can change food availability for benthivorous demersal species by (i) changing benthic prey composition through physical seabed impacts and (ii) by removing overall benthic consumer biomass increasing the net availability of benthic prey for remaining individuals. Thus trawling may both negatively and positively influence the quantity and quality of food available. Using δ 13C and δ 15N we investigated potential diet changes of three commercially exploited species across trawling gradients in the Kattegat (plaice, dab and Norway lobster (Nephrops)) and the Irish Sea (Nephrops). In the Kattegat, trawling affected primarily the biomass of benthic consumers, lowering competition. Nephrops showed significant positive relationships for δ 13C and a domed relationship for δ 15N with trawling. In the Irish Sea, intense trawling had a negative effect on benthic prey. δ 13C and δ 15N thus showed the inverse relationships to those observed in the Kattegat. Plaice from the Kattegat, showed a significant relationship with trawling intensity for δ 13C, but not for δ 15N. No relationship was found for dab. Changes of δ 13C and δ 15N correlated with changes in condition of species. The results show that the removal of demersal competitors and benthos by trawling can change the diets of commercial species, ultimately affecting their body condition.

  19. An Update on Initiatives to Reduce Prawn Trawl Bycatch in the ...

    African Journals Online (AJOL)

    trawl in order to reduce trawled bycatch in the WIO took place off Bagamoyo in 1991 (Mahika 1992). While some initial success was demonstrated, no follow-up studies occurred until 2007, when an. NGO (Tanzania Coastal Management Programme) commenced an investigation of the threat posed by trawlers to turtles in ...

  20. [Impact of trawl fishing on fisheries population components in East China Sea].

    Science.gov (United States)

    Fan, Wei; Zhou, Sufang; Cui, Xuesen; Cheng, Yanhong

    2003-10-01

    Based on the recent 50 years two-boats trawl fishing data of some state-owned fisheries companies and recent 7 years single-boat fishing data of some areas in East China Sea, the trophic index(TI) and composition indexs of fishes of two-boats trawl and single-boat trawl were calculated and analyzed, which indicated that TI increased before 1974 and decreased rapidly thereafter, while composition index decreased from the end of 1970s, but SD increased. The results of single-boat trawl also indicated that TI decreased gradually. Long-term over-fishing of trawl was one of the main reasons of the change of fisheries population structure in East China Sea. All of these showed that there was an over-fishing in East China Sea, and the robust of fisheries population was lower.

  1. Baseline study of the distribution of marine debris on soft-bottom habitats associated with trawling grounds in the northern Mediterranean

    Directory of Open Access Journals (Sweden)

    Pilar Sánchez

    2013-06-01

    Full Text Available The present study aims to analyse the local and regional variability in the density and typology of marine debris on fishing grounds on the northern Mediterranean continental shelf, and to test relationships between marine litter and trawl fishing activity. Moreover, the colonization of plastics was examined in order to study the importance of plastics as a source of impact on marine communities and their further environmental implications. This study surveyed 11 sites, associated with trawling grounds and subjected to different levels of fishing intensity, located in four areas of the Mediterranean: one in Italy, the Central Tyrrhenian coast, one in Greece, the eastern Ionian coast, and two in Spain, the Murcian and Catalan coasts. Samples were collected during an oceanographic cruise undertaken from the 21 May to the 24 June 2009. Results showed geographical variation in the density of marine debris which ranged from 0 to 405 pieces per hectare in the surveyed areas, plastics being the dominant components. Variability within sites was higher than between areas, indicating small-scale patchiness in the distribution of the debris over the seafloor. Though the study areas were within trawling grounds, the density of debris was not significantly correlated with fishing effort. More than 30% of plastics were between 10 and 20 cm width/length, and more than 40% of the plastics were colonized by a biofilm of microorganisms, suggesting indirect effects on benthic communities.

  2. AFSC/NMML: Cetacean line-transect survey in the eastern Bering Sea shelf; 1999, 2000, 2002, and 2004

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Visual surveys for cetaceans were conducted on the eastern Bering Sea shelf along transect lines, in association with the AFSC.s echo integration trawl surveys for...

  3. Golden Crab Logbook Survey (Vessels)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — In November 1995, a voluntary logbook program for the golden crab fishery in the waters under the jurisdiction of the South Atlantic Fishery Management Council...

  4. The 'W' prawn-trawl with emphasised drag-force transfer to its centre line to reduce overall system drag.

    Directory of Open Access Journals (Sweden)

    Cheslav Balash

    Full Text Available For prawn trawling systems, drag reduction is a high priority as the trawling process is energy intensive. Large benefits have occurred through the use of multiple-net rigs and thin twine in the netting. An additional positive effect of these successful twine-area reduction strategies is the reduced amount of otter board area required to spread the trawl systems, which leads to further drag reduction. The present work investigated the potential of redirecting the drag-strain within a prawn trawl away from the wings and the otter boards to the centre line of the trawl, where top and bottom tongues have been installed, with an aim to minimise the loading/size of the otter boards required to spread the trawl. In the system containing the new 'W' trawl, the drag redirected to the centre-line tongues is transferred forward through a connected sled and towing wires to the trawler. To establish the extent of drag redirection to the centre-line tongues and the relative drag benefits of the new trawl system, conventional and 'W' trawls of 3.65 m headline length were tested firstly over a range of spread ratios in the flume tank, and subsequently at optimum spread ratio in the field. The developed 'W' trawl effectively directed 64% of netting-drag off the wings and onto the centre tongues, which resulted in drag savings in the field of ∼20% for the associated 'W' trawl/otter-board/sled system compared to the traditional trawl/otter-board arrangement in a single trawl or twin rig configuration. Furthermore, based on previously published data, the new trawl when used in a twin rig system is expected to provide approximately 12% drag reduction compared to quad rig. The twin 'W' trawl system also has benefits over quad rig in that a reduced number of cod-end/By-catch Reduction Device units need to be installed and attended each tow.

  5. Southeast Alaska cetacean vessel surveys conducted by Alaska Fisheries Science Center, National Marine Mammals Laboratory from 1991-04-20 to 2012-07-20 (NCEI Accession 0140931)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — In 1991, NMML initiated cetacean studies with vessel coverage throughout inland waters of Southeast Alaska. Between 1991 and 1993, line-transect methodology was used...

  6. New research vessels

    Science.gov (United States)

    1984-04-01

    Two “new” ocean-going research vessels operated by the Scripps Institution of Oceanography and the National Science Foundation (NSF) will soon begin full-time scientific duties off the coast of California and in the Antarctic, respectively. The 37.5-m Scripps vessel, named Robert Gordon Sprout in honor of the ex-president of the University of California, replaces the smaller ship Ellen B. Scripps, which had served the institution since 1965. The new ship is a slightly modified Gulf Coast workboat. Under the name of Midnight Alaskan, it had been used for high-resolution geophysical surveys in American and Latin American waters by such firms as Arco Oil & Gas, Exxon, Pennzoil, and Racal-Decca before its purchase by Scripps from a Lousiana chartering firm last summer.

  7. Coral genetic - Taxonomic and genetic identification of deep-sea corals in bycatch and field surveys -linked to groundfish survey dataset

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Data for this project will reside in the West Coast Groundfish Bottom Trawl Survey Data Base. This proposal relates to a continuation and augmentation of our efforts...

  8. Information on fishing vessels and gear dimensions working in areas 35F1-4 and 36F1-4 of the North Sea

    NARCIS (Netherlands)

    Marlen, van B.; Bol, R.A.

    2008-01-01

    This study gives an extract from the Dutch VIRIS database for ICES rectangles 35F1 to 35F4 and 36F1 to 36F4 over the years 2003#2007 by gear type and vessel power. The most common gear type in this area in the beam trawl and most common vessel classes are those with 221 kW (300 hp) and 1471 kW (2000

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

    Science.gov (United States)

    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. Copyright © 2015 Elsevier Ltd. All rights reserved.

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

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — 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...

  11. Occurrence of finfish communities in trawl hauls of Atlantic Ocean in ...

    African Journals Online (AJOL)

    Occurrence of finfish communities in trawl hauls of Atlantic Ocean in Badagry coast, Nigeria. EF Myade, MO Oyebanji, EO Oluwajoba, AB Williams, BC Mbawuike, N Ajuonu, GW Olakunle, OO Adegbile, AY Gadzekpo, MU Umunnakwe, MA Abass ...

  12. NWFSC Observer Trawl Data, off West Coast of US, 2002-2006

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Observer Trawl Data collected during 2002-2006 off West Coast of US. This data product originates from data collected by fishery observers in the West Coast...

  13. Trawling disturbance effects on the trophic ecology of two co-generic Astropectinid species

    Directory of Open Access Journals (Sweden)

    M. C. MANGANO

    2015-09-01

    Full Text Available Physical disturbance by trawling can have both negative and positive effects on populations of scavenging benthic organisms. In the present study the impact of fishing activity on feeding behaviour of the two Astropectinids, Astropecten bispinosus and A. irregularis, was assessed based on stomach contents analysis. The study was carried out along trawled seabed highlighting the positive response of the two facultative scavengers to carrion generated by trawl disturbance. Furthermore, there was greater food specialization in areas that were more heavily exploited by trawling. This specialisation could be linked to the availability of certain prey that results from the passage of fishing gears across the seabed. Interestingly, differences between the two species analysed have been highlighted in term of population dynamic, feeding rate, diet composition and diet diversity, testifying their capacity to coexist in the same fishing grounds.

  14. Assessing and mitigating of bottom trawling. Final BENTHIS project Report (Benthic Ecosystem Fisheries Impact Study)

    DEFF Research Database (Denmark)

    Rijnsdorp, Adriaan D; Eigaard, Ole Ritzau; Kenny, Andrew

    2017-01-01

    (high impact). Additional fishing in these core grounds have only a small impact. In the peripheral areas where fishing intensity is low, additional fishing will have a much larger impact. Hence, shifting trawling activities from the core fishing grounds to the peripheral areas will increase the overall...... to reduce the bycatch and bottom contact in the beam trawl fishery for brown shrimps. Sea trials to replace bottom trawls with pots were inconclusive. Results suggest that creels may offer an alternative for small Nephrops fishers in the Kattegat. In waters off Greece, the catch rates were very low. Sea...... studies carried out in BENTHIS revealed the critical success factors for implementing technological innovations to mitigate trawling impact. While economic investment theory predict that economic profitability should lead to investment in innovative gears, it appeared that many other factors play a role...

  15. Great Lakes Research Vessel Operations 1958-2016

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — The Great Lakes Research Vessel Operations data release is taken from the Research Vessel Catch (RVCAT) database curated at the Great Lakes Science Center (GLSC)....

  16. Great Lakes Research Vessel Operations 1958-2016: OP

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — These data have been collected on various vessel operations on the Great Lakes and select connecting waterways. This vessel operations data set is part of and...

  17. Shell damage and mortality in the common whelk Buccinum undatum caused by beam trawl fishery

    Science.gov (United States)

    Mensink, B. P.; Fischer, C. V.; Cadée, G. C.; Fonds, M.; Ten Hallers-Tjabbes, C. C.; Boon, J. P.

    2000-02-01

    Common whelks Buccinum undatum collected from the southern North Sea were investigated to study the amount of shell damage and mortality caused by beam trawl fishery. The ability of whelks to repair their damaged shells was studied in the laboratory. Whelks ( n=876) were caught with a fine-meshed 3-m beam trawl or with commercial 4- and 12-m beam trawls, while in some areas whelks were also caught with baited traps (used as a reference). Shell damage varied considerably for the different groups. In whelks collected by beam trawling, minor shell damage was observed in 17-75%, and severe damage (when protection against predators and scavengers is lost) in 10-83%. Whelks caught with baited traps sustained only minor shell damage (0-27% of the individuals). Their damage was statistically significantly less than in beam-trawled specimens. Most whelks in all groups exhibited signs of former shell damage, which had since been repaired. Whelk survival was studied in the laboratory over a six-week period. Only 40% of the whelks caught with the 12-m beam trawl survived, irrespective of the damage suffered. Whelks that survived and recovered had repaired their shell after six weeks. More than 95% of the whelks caught with baited traps survived the six-week experimental period; this is statistically significantly higher than the survival of animals caught with the 12-m beam trawl. At five locations females were screened for the presence and stage of imposex. Mild imposex development (mostly stages 1 and 2) was observed at all locations with incidences of 32-80%. It is concluded that beam trawl fishery may be a much greater source of mortality in common whelks than previously thought.

  18. Vessel Operator System

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Operator cards are required for any operator of a charter/party boat and or a commercial vessel (including carrier and processor vessels) issued a vessel permit from...

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

    Science.gov (United States)

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

    2014-06-17

    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.

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

    Science.gov (United States)

    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.

  1. 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

    Science.gov (United States)

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

    2016-08-01

    surveying is an efficient technique to assess abundance and species composition in deep-sea waters for these motile species and questions trawl-based estimations.

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

    Science.gov (United States)

    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.

  3. Synthetic Aperture Sonar Survey to Locate Archaeological Resources in the Stellwagen Bank National Marine Sanctuary on NOAA Office of National Marine Sanctuaries vessel SRVx between 20100823 and 20100901

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — SAS technology exemplifies recent advances in geophysical survey technology that will revolutionize maritime archaeological remote sensing. Applied Signal Technology...

  4. From fishing to fish processing: Separation of fish from crustaceans in the Norway lobster-directed multispecies trawl fishery improves seafood quality

    DEFF Research Database (Denmark)

    Karlsen, Junita Diana; Krag, Ludvig Ahm; Albertsen, Christoffer Moesgaard

    2015-01-01

    the opportunity to selectively reduce small low-value fish, which will reduce catch weight and sorting time onboard the vessel. For this horizontally divided test codend and a standard codend, in which the catch was mixed, quality assessments were performed on the same batches of fish during three steps...... with hard or spiny surfaces due to successful separation of fish and Norway lobster into the upper and lower codends, respectively, and by lower catch weight in the upper codend of the test codend compared with the standard codend. The decrease in damages may also improve quality indirectly by inflicting......Fishing gears have negative impacts on seafood quality, especially on fish in the mixed trawl fishery targeting Norway lobster (Nephrops norvegicus). In this fishery, which is worth about €80 millions in Denmark alone, the quality of fish can be significantly improved by simple gear changes...

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

    Science.gov (United States)

    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

  6. BIOASSAY VESSEL FAILURE ANALYSIS

    Energy Technology Data Exchange (ETDEWEB)

    Vormelker, P

    2008-09-22

    Two high-pressure bioassay vessels failed at the Savannah River Site during a microwave heating process for biosample testing. Improper installation of the thermal shield in the first failure caused the vessel to burst during microwave heating. The second vessel failure is attributed to overpressurization during a test run. Vessel failure appeared to initiate in the mold parting line, the thinnest cross-section of the octagonal vessel. No material flaws were found in the vessel that would impair its structural performance. Content weight should be minimized to reduce operating temperature and pressure. Outer vessel life is dependent on actual temperature exposure. Since thermal aging of the vessels can be detrimental to their performance, it was recommended that the vessels be used for a limited number of cycles to be determined by additional testing.

  7. Indirect effects of otter trawling on the condition and trophic level of Nephrops and flatfish in the Kattegat

    DEFF Research Database (Denmark)

    Hiddink, Jan Geert; Balestrin, Stephen; Moranta, Joan

    The fishing gear used in bottom trawl fisheries cause mortality of benthic invertebrates and this can decrease the long-term availability of prey to exploited fish species by reducing the abundance of benthic invertebrates. Alternatively, low trawling levels could increase food production for spe...

  8. 50 CFR Figure 7 to Part 679 - Location of Trawl Gear Test Areas in the GOA and the BSAI

    Science.gov (United States)

    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...

  9. 75 FR 61642 - Fisheries of the Exclusive Economic Zone Off Alaska; Modified Nonpelagic Trawl Gear and Habitat...

    Science.gov (United States)

    2010-10-06

    ... near the Bering Strait that was open to nonpelagic trawling (Figure 2) but that will now be closed. The... Natives in the Bering Strait region have voiced their opposition to any nonpelagic trawling in the... failure of NMFS to include any of the subsistence-based communities in the Bering Strait region in the...

  10. Pulse trawl fishing: characteristics of the electrical stimulation and the effect on behaviour and injuries of Atlantic cod (Gadus morhua)

    NARCIS (Netherlands)

    Haan, de D.; Fosseidengen, J.E.; Fjelldal, P.G.; Burggraaf, D.; Rijnsdorp, A.D.

    2016-01-01

    In the North Sea flatfish fishery, electric pulse trawls have been introduced to replace the conventional mechanical method. Pulse trawls reduce the fuel consumption, reduce adverse impact on the ecosystem but cause injuries in gadoids. We describe the design and electrical properties of pulse

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

    Science.gov (United States)

    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.

  12. Are Cape gannets dependent upon fishery waste? A multi‐scale analysis using seabird GPS‐tracking, hydro‐acoustic surveys of pelagic fish and vessel monitoring systems

    National Research Council Canada - National Science Library

    Tew Kai, Emilie; Benhamou, Simon; Lingen, Carl D; Coetzee, Janet C; Pichegru, Lorien; Ryan, Peter G; Grémillet, David; Votier, Steve

    2013-01-01

    ... at‐sea surveys, and fishing effort by the two main south African fisheries (purse seiners that compete with seabirds for pelagic fish, and demersal trawlers that process fish at sea and discharge fish waste...

  13. An Improved Backstepping-Based Controller for Three-Dimensional Trajectory Tracking of a Midwater Trawl System

    Directory of Open Access Journals (Sweden)

    Zhao Yan

    2016-01-01

    Full Text Available An improved backstepping control method for three-dimensional trajectory tracking of a midwater trawl system is investigated. A new mathematical model of the trawl system while considering the horizontal expansion effect of two otter boards is presented based on the Newton Euler method. Subsequently, an active path tracking strategy of the trawl system based on the backstepping method is proposed. The nonstrict feedback characteristic of the proposed model employs a control allocation method and several parallel nonlinear PID (Proportion Integration Differentiation controllers to eliminate the high-order state variables. Then, the stability analysis by the Lyapunov Stability Theory shows that the proposed controller can maintain the stability of the trawl system even with the presence of external disturbances. To validate the proposed controller, a simulation comparison with a linear PID controller was conducted. The simulation results illustrate that the improved backstepping controller is effective for three-dimensional trajectory tracking of the midwater trawl system.

  14. Influence of twin and multi-rig trawl systems on CPUE in the Danish Norway lobster (Nephrops norvegicus) fishery

    DEFF Research Database (Denmark)

    Feekings, Jordan P.; Berg, Casper Willestofte; Krag, Ludvig Ahm

    2016-01-01

    One of the most effective ways to alter catch and length compositions in trawls is to adjust the meshsize or add selective devices such as sorting grids and selective netting panels. These changes are oftenintroduced into the fishery in a top down manner whereby fishermen are forced to comply...... with spe-cific legislation. However, fishermen have also introduced gear modifications that have contributed toimproving species selectivity in trawls. One of the simplest and most effective modifications that camefrom industry was the development and introduction of twin and multi-rig trawls. Here we...... years (1997–2012).Results showed that catch rates of Nephrops in multi-rig trawls were significantly higher (1.89–2.03)than those in single trawls. For cod, haddock and plaice there was no significant effect of gear type. Theresults are discussed in relation to the Common Fisheries Policy reform...

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

    DEFF Research Database (Denmark)

    van Denderen, Pieter Daniël; Rijnsdorp, Adriaan D.; van Kooten, Tobias

    2016-01-01

    Marine protected areas (MPAs) are widely used to protect exploited fish species as well as to conserve marine habitats and their biodiversity. They have become a popular management tool also 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...

  16. Bottom trawling affects fish condition through changes in the ratio of prey availability to density of competitors

    DEFF Research Database (Denmark)

    Hiddink, Jan Geert; Moranta, Joan; Balestrini, Stephen

    2016-01-01

    and applications. Our study indicates that fish production may be maximized by keeping bottom-trawling intensities relatively low, although this may negatively ffect the economically more important Nephrops fishery. The effects of bottom trawls may be mitigated by switching to gears, which affect prey availability......1. Bottom-trawl fisheries are widespread and cause mortality of benthic invertebrates, which in turn may lead to a decrease in the availability of prey for target fish species. Exploitation also reduces the abundance of the fish species themselves. Modelling studies have shown that bottom trawling...... could lead to both increases and decreases in fish production, but so far empirical evidence to test these ideas has been very limited. We hypothesize that the effect of bottom trawling on the food intake and condition of fish depends on how the ratio of prey to consumers changes with increasing fishing...

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

    Science.gov (United States)

    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. Copyright © 2014 Elsevier B.V. All rights reserved.

  18. Guam Abandoned Vessel Inventory

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — NOAA Abandoned Vessel Project Data for Guam. Abandoned vessels pose a significant threat to the NOAA Trust resources through physical destruction of coral habitats...

  19. Florida Abandoned Vessel Inventory

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — NOAA Abandoned Vessel Project Data for Florida. Abandoned vessels pose a significant threat to the NOAA Trust resources through physical destruction of coral...

  20. Vessel Arrival Info - Legacy

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The Vessel Arrival Info is a spreadsheet that gets filled out during the initial stage of the debriefing process by the debriefer. It contains vessel name, trip...

  1. Lost in translation? Multi-metric macrobenthos indicators and bottom trawling

    DEFF Research Database (Denmark)

    Gislason, Henrik; Bastardie, Francois; Dinesen, Grete E.

    2017-01-01

    The member states of the European Union use multi-metric macrobenthos indicators to monitor the ecological status of their marine waters in relation to the Water Framework and Marine Strategy Framework Directives. The indicators translate the general descriptors of ecological quality...... trawling. We use linear mixed effects models to analyze how bottom trawling intensity affects the indicators used in the Danish (Danish Quality Index, DKI) and Swedish (Benthic Quality Index, BQI) environmental monitoring programs in the Kattegat, the sea area between Sweden and Denmark. Using year...

  2. Towards a framework for the quantitative assessment of trawling impact on the seabed and benthic ecosystem

    DEFF Research Database (Denmark)

    Rijnsdorp, A. D.; Bastardie, Francois; Bolam, S.G.

    2016-01-01

    and considers the physical effects of trawl gears on the seabed, on marine taxa, and on the functioning of the benthic ecosystem. Within the frame- work, a reductionist approach is applied that breaks down a fishing gear into its components, and a number of biological traits are chosen to de- termine either...... the vulnerability of the benthos to the impact of that gear component, or to provide a proxy for their ecological role. The approach considers gear elements, such as otter boards, twin trawl clump, and groundrope, and sweeps that herd the fish. The physical impact of these ele- ments on the seabed, comprising...

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

    Science.gov (United States)

    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

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

    Directory of Open Access Journals (Sweden)

    Francesco Colloca

    Full Text Available 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

  5. ALICE HMPID Radiator Vessel

    CERN Multimedia

    2003-01-01

    View of the radiator vessels of the ALICE/HMPID mounted on the support frame. Each HMPID module is equipped with 3 indipendent radiator vessels made out of neoceram and fused silica (quartz) windows glued together. The spacers inside the vessel are needed to stand the hydrostatic pressure. http://alice-hmpid.web.cern.ch/alice-hmpid

  6. Great Lakes Research Vessel Operations 1958-2016: Mysis

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — All mysis data represented here expand upon vessel operations (OP table) data, all of which are collected by the United States Geological Survey, Great Lakes Science...

  7. Great Lakes Research Vessel Operations 1958-2016: Mensuration

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — All mensuration data represented here expand upon vessel operations (OP table) data, all of which are collected by the United States Geological Survey, Great Lakes...

  8. Great Lakes Research Vessel Operations 1958-2016: Gillnet

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — All gillnet data represented here expand upon vessel operations (OP table) data, all of which are collected by the United States Geological Survey, Great Lakes...

  9. Great Lakes Research Vessel Operations 1958-2016: Benthos Ponar

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — All benthos data represented here expand upon vessel operations (OP table) data, all of which are collected by the United States Geological Survey, Great Lakes...

  10. Deep-Sea Mega-Epibenthic Assemblages from the SW Portuguese Margin (NE Atlantic Subjected to Bottom-Trawling Fisheries

    Directory of Open Access Journals (Sweden)

    Sofia P. Ramalho

    2017-11-01

    Full Text Available Bottom-trawling fisheries are a common threat to the health of continental margins worldwide. Together with numerous environmental and biological processes, physical disturbance induced by trawlers can largely shape the benthic habitats and their associated assemblages. At the SW Portuguese Margin, crustacean bottom trawlers have exploited deep-sea habitats for a few decades, but its effects on the benthic biodiversity are practically unknown. During the spring-summer of 2013 and 2014, several Remotely Operated Vehicle (ROV video transects were used to investigate mega-epibenthic abundance, composition, and diversity in soft-sediment areas subjected to varying trawling pressures off Sines and Setúbal (200–800 m. Differences in mega-epibenthic assemblages were linked with environmental changes (depth, grain size, primary productivity and trawling disturbance. The effect of trawling was assessed between segments with similar habitat characteristics, i.e., muddy-sand bottoms between 300 and 500 m. Areas subjected to intensive trawling pressure showed a generally flattened seabed, with abundant recent trawl marks (up to 3 scars.100 m−1, indicating that the seabed physical integrity was compromised. Significant negative correlations were detected between various mega-epibenthic diversity indices [S, H′, and ET(20] and trawling pressure (h.cell−1.y−1. Furthermore, the distinct mega-epibenthic assemblages and absence of several sessile erect morphospecies at both low and highly disturbed locations by trawling off Sines, namely all seapen morphospecies found in non-trawled areas, demonstrates the negative influence of trawling fisheries on the benthic component of the study area. Also, low dissimilarity between assemblages from the main fishing grounds and the adjacent low-disturbance locations, suggests that the potentially negative influence of trawling can extend beyond the targeted areas (e.g., by the plumes of re-suspended sediments. The

  11. Thermophysiological responses and work strain in fishermen on deep-sea fishing vessels.

    Science.gov (United States)

    Høye, Erik Ulvolden; Sandsund, Mariann; Heidelberg, Cecilie Thon; Aasmoe, Lisbeth; Reinertsen, Randi Eidsmo

    2016-01-01

    Fishermen working on deep-sea vessels in the Barents and Norwegian Sea are exposed to low air temperatures, strong winds, high humidity, rain, snow and work at different intensities. Few studies have investigated the effect of environmental work factors on the physiology of this occupational group. The aim of the study was to investigate work strain and thermophysiological responses of fishermen on the trawl and factory decks of deep-sea vessels. Twenty-five professional male fishermen (age 39 ± 13 years) were recruited to the study which was performed on three trawlers in the Norwegian Sea in April, June and August 2014. During a six-hour shift, heart rate (HR), core (Tc) and mean skin (Ts) temperatures were recorded, and questions about subjective thermal sensation and comfort were answered. Short periods of hard (above 86% of HRmax) work raised Tc by 0.8°C to 37.8°C and decreased Ts by 2.3°C to 29.8°C during work on the trawl deck, and subjects reported being warm and sweaty. On the factory deck long periods of fairly light (between 52% and 66% HRmax) work, Tc of 37.4°C and Ts of 30.9°C were measured. Fishermen experience intermittent periods of heavy work on the trawl deck shown with elevated core temperature and HR. Work on the factory deck includes long periods of repetitive work with light to moderate work strain. A better understanding of work strain and environmental challenges during work on Norwegian deep-sea vessels will help identify exposure risks during work in the cold and heat.

  12. Minimally Invasive Treatment of Pediatric Extrinsic Ureteropelvic Junction Obstruction by Crossing Polar Vessels: Is Vascular Hitching a Definitive Solution? Report of a Multicenter Survey.

    Science.gov (United States)

    Chiarenza, Salvatore Fabio; Bleve, Cosimo; Caione, Paolo; Escolino, Maria; Nappo, Simona Gerocarni; Perretta, Rosa; La Manna, Angela; Esposito, Ciro

    2017-09-01

    This article aimed to evaluate the outcome of laparoscopic vascular hitch (VH) as an effective alternative to dismembered pyeloplasty in the treatment of children with extrinsic ureteropelvic junction obstruction (UPJO) by crossing vessels (CVs), by reporting the experience of three Italian centers of Pediatric Surgery. From 2006 to 2014, 54 children (18 girls and 36 boys, average age 10.7 years) affected by suspected extrinsic UPJO by CV were treated in three different institutions: 51 patients underwent laparoscopic VH, while 3 patients, in which a coexisting intrinsic etiology of UPJO was doubtful, underwent laparoscopic dismembered pyeloplasty. Preoperative diagnostic workup included: ultrasound (US)/Doppler scan, mercaptoacetyltriglycine (MAG3)-renal scan, and functional-magnetic-resonance-urography (fMRU). Symptoms at presentation were recurrent abdominal/flank pain and hematuria. All patients presented intermittent hydronephrosis (range 18-100 mm) on US and an obstructive pattern on MAG3 renogram. Average operative time was 108 minutes, and average hospital stay was 1.8 days. As for complications, we reported a small abdominal wall hematoma and a high UPJ distortion without obstruction in 2 patients, not requiring reintervention (grade I Clavien-Dindo). At follow-up (range 12-96 months), all patients reported resolution of symptoms, decrease in the hydronephrosis grade, and improved drainage on MAG3 renogram. Our results demonstrated the safety and efficacy of laparoscopic VH for treatment of extrinsic UPJO by CV, registering excellent outcomes in a very selected patient population. The careful selection of patients through intraoperative assessment of anatomical and functional aspects is a crucial step to confirm indications for VH and maintain a high success rate with the procedure. We believe that any concerns regarding the coexistence of intrinsic stenosis should certainly lead to opening the collecting system and to performing a classic dismembered

  13. Bycatch in 36 and 40 mm PA Turkish twin rigged beam trawl codends

    African Journals Online (AJOL)

    ... which are caught by the beam trawl fishery with nominal mesh sizes 36 and 40 mm PA (diamond) codend in the Sea of Marmara (Turkey) and also on the minimum landing size (MLS) established for Merluccius merluccius, Merlangius merlangus euxinus, Mullus surmuletus, Trachurus trachurus and Pomatomus saltatrix.

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

    Science.gov (United States)

    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

  15. Comparison of gill nets and fixed-frame trawls for sampling threadfin shad in tropical reservoirs

    Czech Academy of Sciences Publication Activity Database

    Prchalová, Marie; Neal, J. W.; Munoz-Hincapie, M.; Jůza, Tomáš; Říha, Milan; Peterka, Jiří; Kubečka, Jan

    2012-01-01

    Roč. 141, č. 4 (2012), s. 1151-1160 ISSN 0002-8487 R&D Projects: GA ČR(CZ) GPP505/12/P647 Institutional support: RVO:60077344 Keywords : threadfin shad * gillnet * trawl * gear selectivity * catchability * reservoir Subject RIV: EH - Ecology, Behaviour Impact factor: 1.546, year: 2012

  16. Discards Management: reducing plaice discards via beam-trawl effort reallocations

    NARCIS (Netherlands)

    Uhlmann, S.S.; Poos, J.J.; Aarts, G.M.; Helmond, van A.T.M.

    2012-01-01

    Ways to improve the well-being and likewise to reduce the number of fish returned to sea as unwanted waste (‘discards’) have received major attention by the Dutch commercial beam-trawl fishing sector, and responsible ministries. There are various options to achieve this: make the gear more selective

  17. Questioning the effectiveness of technical measures implemented by the Basque bottom otter trawl fleet

    NARCIS (Netherlands)

    Alzorriz, N.; Arregi, L.; Herrmann, B.; Sistiaga, M.; Casey, J.; Poos, J.J.

    2016-01-01

    The selective properties of a bottom trawl fitted with a 70 mm diamond mesh codend and a 100 mm top square mesh panel (SMP) for hake (Merluccius merluccius), pouting (Trisopterus luscus and Trisopterus minutus) and red mullet (Mullus surmuletus) were investigated over the period 2011-2013. The

  18. Antarctic krill; assessment of mesh size selectivity and escape mortality from trawls

    DEFF Research Database (Denmark)

    Krafft, Bjørn A.; Krag, Ludvig Ahm; Herrmann, Bent

    2015-01-01

    in Trawls (NEAT), presented in WG-EMM 2012/24, WGEMM 2013/34, WG-EMM 2014/14 and WG-EMM 2014/16. Funding is provided by the Norwegian Research Council and ship-time for executing the field-experiments is offered free-of-charge by two Norwegian commercial fishing companies; Olympic Seafood AS and Aker Bio...

  19. Analysis of bycatch in the South African midwater trawl fishery for ...

    African Journals Online (AJOL)

    There are species overlaps with various fisheries, namely the demersal trawl, small-pelagic, line, shark longline and squid fisheries, yet the total bycatch estimates from this fishery are generally small relative to catches taken in the target fisheries. Bycatch species with the highest average annual catches were chub ...

  20. Bycatch in 36 and 40 mm PA Turkish twin rigged beam trawl codends

    African Journals Online (AJOL)

    Jane

    2011-07-20

    Jul 20, 2011 ... amount of bycatch in the region of high species diversity. Experiments suggest that selectivity can be ... coastal zone by small beam trawlers with a maximum engine power of 160 hp (Zengin et al., 2004). ..... (southern Portugal) crustacean trawl fishery. Hydrobiologia, 449(1-3):. 267-277. Ozbilgin YD ...

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

    DEFF Research Database (Denmark)

    Kronbak, Lone Grønbæk; Nielsen, J. Rasmus; Jørgensen, Ole A.

    2009-01-01

    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....

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

    Science.gov (United States)

    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

  3. Pressure vessel design manual

    CERN Document Server

    Moss, Dennis R

    2013-01-01

    Pressure vessels are closed containers designed to hold gases or liquids at a pressure substantially different from the ambient pressure. They have a variety of applications in industry, including in oil refineries, nuclear reactors, vehicle airbrake reservoirs, and more. The pressure differential with such vessels is dangerous, and due to the risk of accident and fatality around their use, the design, manufacture, operation and inspection of pressure vessels is regulated by engineering authorities and guided by legal codes and standards. Pressure Vessel Design Manual is a solutions-focused guide to the many problems and technical challenges involved in the design of pressure vessels to match stringent standards and codes. It brings together otherwise scattered information and explanations into one easy-to-use resource to minimize research and take readers from problem to solution in the most direct manner possible. * Covers almost all problems that a working pressure vessel designer can expect to face, with ...

  4. The Camera-Based Assessment Survey System (C-BASS): A towed camera platform for reef fish abundance surveys and benthic habitat characterization in the Gulf of Mexico

    Science.gov (United States)

    Lembke, Chad; Grasty, Sarah; Silverman, Alex; Broadbent, Heather; Butcher, Steven; Murawski, Steven

    2017-12-01

    An ongoing challenge for fisheries management is to provide cost-effective and timely estimates of habitat stratified fish densities. Traditional approaches use modified commercial fishing gear (such as trawls and baited hooks) that have biases in species selectivity and may also be inappropriate for deployment in some habitat types. Underwater visual and optical approaches offer the promise of more precise and less biased assessments of relative fish abundance, as well as direct estimates of absolute fish abundance. A number of video-based approaches have been developed and the technology for data acquisition, calibration, and synthesis has been developing rapidly. Beginning in 2012, our group of engineers and researchers at the University of South Florida has been working towards the goal of completing large scale, video-based surveys in the eastern Gulf of Mexico. This paper discusses design considerations and development of a towed camera system for collection of video-based data on commercially and recreationally important reef fishes and benthic habitat on the West Florida Shelf. Factors considered during development included potential habitat types to be assessed, sea-floor bathymetry, vessel support requirements, personnel requirements, and cost-effectiveness of system components. This regional-specific effort has resulted in a towed platform called the Camera-Based Assessment Survey System, or C-BASS, which has proven capable of surveying tens of kilometers of video transects per day and has the ability to cost-effective population estimates of reef fishes and coincident benthic habitat classification.

  5. Maury Journals - German Vessels

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — German vessels observations, after the 1853 Brussels Conference that set International Maritime Standards, modeled after Maury Marine Standard Observations.

  6. 76 FR 20891 - Fisheries of the Exclusive Economic Zone Off Alaska; Pacific Cod by Catcher Vessels Using Trawl...

    Science.gov (United States)

    2011-04-14

    ...: Effective 1200 hrs, Alaska local time (A.l.t.), April 9, 2011, through 1200 hrs, A.l.t., April 12, 2011.... Comment will generally be posted without change. All Personal Identifying Information (for example, name... fisheries data in a timely fashion and would delay the opening of directed fishing for Pacific cod by...

  7. Mothership Cost Earnings Data - Economic Data Collection for Monitoring the Economic Effects of the West Coast Groundfish Trawl Rationalization Program

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This project was initiated in response to regulation 50 CFR 660.114, which mandates that economic data be collected from every participant in the trawl...

  8. NPRB711 Quantification of unobserved injury and mortality of Bering Sea crabs due to encounters with trawls on the seafloor

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The potential for unobserved mortality of crabs encountering bottom trawls, but not captured, has long been a concern in the management of Bering Sea fisheries. We...

  9. PRESSURE-RESISTANT VESSEL

    NARCIS (Netherlands)

    Beukers, A.; De Jong, T.

    1997-01-01

    Abstract of WO 9717570 (A1) The invention is directed to a wheel-shaped pressure-resistant vessel for gaseous, liquid or liquefied material having a substantially rigid shape, said vessel comprising a substantially continuous shell of a fiber-reinforced resin having a central opening, an inner

  10. Improving the size- and species selectivity of cod (Gadus morhua) in demersal mixed-species trawl fisheries

    OpenAIRE

    Krag, Ludvig Ahm

    2009-01-01

    For the last decade, the Kattegat-Skagerrak and the North Sea cod stocks have been at a critically low level. Several management initiatives were introduced to protect and aid the recovery of these cod stocks. Most fisheries in these areas are conducted in a multispecies setting, where several different species, including cod, are caught together. Demersal trawling is the predominant fishing method in Denmark, as measured by both catch value and volume. Demersal trawls also account for the hi...

  11. Containment vessel drain system

    Energy Technology Data Exchange (ETDEWEB)

    Harris, Scott G.

    2018-01-30

    A system for draining a containment vessel may include a drain inlet located in a lower portion of the containment vessel. The containment vessel may be at least partially filled with a liquid, and the drain inlet may be located below a surface of the liquid. The system may further comprise an inlet located in an upper portion of the containment vessel. The inlet may be configured to insert pressurized gas into the containment vessel to form a pressurized region above the surface of the liquid, and the pressurized region may operate to apply a surface pressure that forces the liquid into the drain inlet. Additionally, a fluid separation device may be operatively connected to the drain inlet. The fluid separation device may be configured to separate the liquid from the pressurized gas that enters the drain inlet after the surface of the liquid falls below the drain inlet.

  12. Daily variation of fishing effort and ex-vessel prices in a western Mediterranean multi-species fishery: Implications for sustainable management

    OpenAIRE

    Samy-Kamal, Mohammed; Forcada, Aitor; Sánchez-Lizaso, José Luis

    2015-01-01

    The daily variation of fishing effort and ex-vessel price was analysed to determine which day of the week is suitable to ban the fishery, as an alternative management measure to the one month seasonal closure. Thus, 10-years landings data were used from two representative trawling ports of the western Mediterranean: Dénia and La Vila Joiosa. Analysis of variance (ANOVA) was used to detect significant differences in fishing effort (total and by métier) and daily ex-vessel price of the main tar...

  13. Quantifying the escape mortality of trawl caught Antarctic krill (Euphausia superba)

    DEFF Research Database (Denmark)

    Krafft, Bjørn A; Krag, Ludvig Ahm; Engås, Arill

    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 esti......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...

  14. Improving the effectiveness of escape windows in directed Norway lobster Nephrops norvegicus trawl fisheries

    DEFF Research Database (Denmark)

    Madsen, Niels; Holst, René; Frandsen, Rikke

    2012-01-01

    A substantial improvement in the bycatch selectivity of Norway lobster Nephrops norvegicus trawls is required, particularly with respect to cod Gadus morhua , whose stocks are at low levels in several areas. Conventional escape windows are not adequate to properly release cod and other bycatch...... species caught in the trawls. To address this issue, we developed a novel sorting box concept consisting of a four-panel section with a window on the top in order to improve the escape of cod and other bycatch species through an escape window while retaining the target catch of Norway lobster. The concept....... The reduction in bycatch decreased with decreasing mesh size and increasing height of the sorting box. Escape of Norway lobster through the escape window was limited. A modified version of the sorting box concept was implemented in the Kattegat fishery from 2009 onwards...

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

    Science.gov (United States)

    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.

  16. The vertical separation of fish in the aft end of a demersal trawl

    DEFF Research Database (Denmark)

    Krag, Ludvig Ahm; Holst, René; Madsen, Niels

    2009-01-01

    Two multi-compartment separator frames were used to study the vertical separation of some commercially important fish species in the aft end of a trawl, with the aim of separating cod (Gadus morhua) from other species. A non-linear multinomial model with random effects was used to analyse the data....... The use of guiding bars in the separator frame significantly (p fish resulted in a more uniform distribution of cod. The species separations found...

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

    Science.gov (United States)

    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.

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

    OpenAIRE

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

    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 ...

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

    DEFF Research Database (Denmark)

    Grønbæk Kronbak, Lone; Nielsen, J. Rasmus; Jørgensen, Ole A.

    2009-01-01

    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. (C) 2009 Elsevier Ltd. All rights reserved....

  20. SURVEY

    DEFF Research Database (Denmark)

    SURVEY er en udbredt metode og benyttes inden for bl.a. samfundsvidenskab, humaniora, psykologi og sundhedsforskning. Også uden for forskningsverdenen er der mange organisationer som f.eks. konsulentfirmaer og offentlige institutioner samt marketingsafdelinger i private virksomheder, der arbejder...

  1. Bycatch of crustacean and fish bottom trawl fisheries from southern Portugal (Algarve

    Directory of Open Access Journals (Sweden)

    Maria Esmeralda Costa

    2008-12-01

    Full Text Available As part of two research projects for analysing bycatch and discards, we quantified catch composition, catch rates, bycatch and discards in two important commercial bottom trawl fisheries (crustacean and fish trawls off the southern coast of Portugal (Algarve. Stratified sampling by onboard observers took place from February 1999 to March 2001 and data were collected from 165 tows during 52 fishing trips. Commercial target species included crustaceans: blue and red shrimp (Aristeus antennatus, deep-water rose shrimp (Parapenaeus longirostris, Norway lobster (Nephrops norvegicus; and fishes: seabreams (Diplodus spp. and Pagellus spp., horse mackerels (Trachurus spp. and European hake (Merluccius merluccius. The trawl fisheries are characterised by considerable amounts of bycatch: 59.5% and 80.4% of the overall total catch for crustacean and fish trawlers respectively. A total of 255 species were identified, which belonged to 15 classes of organisms (137 vertebrates, 112 invertebrates and 6 algae. Crustacean trawlers had higher bycatch biodiversity. Bony fish (45.6% and 37.8% followed by crustaceans (14.6% and 11.5% were the dominant bycatch components of both crustacean and fish trawlers respectively. The influence of a number of factors (e.g. depth, fishing gear, tow duration and season on bycatch and discards is discussed.

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

    Science.gov (United States)

    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.

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

    Science.gov (United States)

    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.

  4. During the British Antarctic Survey's Offshore Biological Programme ...

    African Journals Online (AJOL)

    spamer

    During the British Antarctic Survey's Offshore. Biological Programme (latterly Pelagic Ecosystem. Studies Programme), two specimens of a cephalopod belonging to the squid family Chiroteuthidae were caught in the Scotia Sea by rectangular midwater trawl. (Baker et al. 1973). The material closely resembles. Chiroteuthis ...

  5. From Fishing to Fish Processing: Separation of Fish from Crustaceans in the Norway Lobster-Directed Multispecies Trawl Fishery Improves Seafood Quality.

    Science.gov (United States)

    Karlsen, Junita D; Krag, Ludvig Ahm; Albertsen, Christoffer Moesgaard; Frandsen, Rikke Petri

    2015-01-01

    Fishing gears have negative impacts on seafood quality, especially on fish in the mixed trawl fishery targeting Norway lobster (Nephrops norvegicus). In this fishery, which is worth about €80 millions in Denmark alone, the quality of fish can be significantly improved by simple gear changes. A trawl codend divided into an upper and lower codend was designed to separate fish from Norway lobster during the fishing process by encourage fish to swim into the upper codend by using a frame at the entrance of the lower codend. Separate codends for fish and Norway lobster in the same gear provide the opportunity to selectively reduce small low-value fish, which will reduce catch weight and sorting time onboard the vessel. For this horizontally divided test codend and a standard codend, in which the catch was mixed, quality assessments were performed on the same batches of fish during three steps of the value chain: i) aboard the fishing vessel; ii) at the Fishermen's Collection Central, and iii) in the production plant. Four species of fish and fillets from fish caught in the upper codend of the test codend were of significantly better quality for several of the assessed parameters compared with those caught in the standard codend: i) newly caught fish showed significantly less scale loss and discolourations and had significantly better texture; ii) landed fish had significantly better skin appearance and texture and significantly fewer discolourations; and iii) fillets showed significantly fewer blood spots and had significantly better texture. There were no differences in injuries for newly caught fish or gaping and bruises for fillets between the test and standard codends. The decrease in catch-related damages in the test codend is explained by little contact between fish and animals with hard or spiny surfaces due to successful separation of fish and Norway lobster into the upper and lower codends, respectively, and by lower catch weight in the upper codend of the

  6. Exploring the degree of trawling disturbance by the analysis of benthic communities ranging from a heavily exploited fishing ground to an undisturbed area in the NW Mediterranean

    Directory of Open Access Journals (Sweden)

    Silvia de Juan

    2011-04-01

    Full Text Available This study focuses on 4 sites in the northwestern Mediterranean to investigate the response of benthic fauna across a gradient of trawling impact. One site was located in a heavily exploited fishing ground. The second site was enclosed in the fishing ground but had not been trawled in twenty years. The third site was located adjacent to a marine protected area and was subjected to occasional trawling. The fourth site was located inside the marine protected area, where trawling was banned thirty years ago. Side-scan sonar records of trawl marks on the seabed confirmed the gradient of trawling intensity. We investigated the response of benthic fauna to trawling disturbance at the mesoscale of a fishing ground. We compared the observed patterns of abundance, biomass, diversity and community structure for epifauna and infauna with responses predicted from previous studies. Results showed that those communities less impacted by trawling sustained more biogenically habitat-structured communities (e.g. more abundance of sessile suspension feeders at the less disturbed sites against higher dominance of small invertebrates at the disturbed site. Moreover, these results confirm the benefits of restricting trawling activities for benthic communities, with marine reserves as the paradigm for the conservation of Mediterranean fishing grounds.

  7. 2013 Vessel Density

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Automatic Identification Systems (AIS) are a navigation safety device that transmits and monitors the location and characteristics of many vessels in U.S. and...

  8. 2011 Passenger Vessel Density

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Automatic Identification Systems (AIS) are a navigation safety device that transmits and monitors the location and characteristics of many vessels in U.S. and...

  9. 2011 Vessel Density

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Automatic Identification Systems (AIS) are a navigation safety device that transmits and monitors the location and characteristics of many vessels in U.S. and...

  10. 2013 Passenger Vessel Density

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Automatic Identification Systems (AIS) are a navigation safety device that transmits and monitors the location and characteristics of many vessels in U.S. and...

  11. 2013 Tanker Vessel Density

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Automatic Identification Systems (AIS) are a navigation safety device that transmits and monitors the location and characteristics of many vessels in U.S. and...

  12. 2013 Cargo Vessel Density

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Automatic Identification Systems (AIS) are a navigation safety device that transmits and monitors the location and characteristics of many vessels in U.S. and...

  13. High Performance Marine Vessels

    CERN Document Server

    Yun, Liang

    2012-01-01

    High Performance Marine Vessels (HPMVs) range from the Fast Ferries to the latest high speed Navy Craft, including competition power boats and hydroplanes, hydrofoils, hovercraft, catamarans and other multi-hull craft. High Performance Marine Vessels covers the main concepts of HPMVs and discusses historical background, design features, services that have been successful and not so successful, and some sample data of the range of HPMVs to date. Included is a comparison of all HPMVs craft and the differences between them and descriptions of performance (hydrodynamics and aerodynamics). Readers will find a comprehensive overview of the design, development and building of HPMVs. In summary, this book: Focuses on technology at the aero-marine interface Covers the full range of high performance marine vessel concepts Explains the historical development of various HPMVs Discusses ferries, racing and pleasure craft, as well as utility and military missions High Performance Marine Vessels is an ideal book for student...

  14. Cheboygan Vessel Base

    Data.gov (United States)

    Federal Laboratory Consortium — Cheboygan Vessel Base (CVB), located in Cheboygan, Michigan, is a field station of the USGS Great Lakes Science Center (GLSC). CVB was established by congressional...

  15. Maury Journals - US Vessels

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — U.S. vessels observations, after the 1853 Brussels Conference that set International Maritime Standards, modeled after Maury Marine Standard Observations.

  16. 2011 Cargo Vessel Density

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Automatic Identification Systems (AIS) are a navigation safety device that transmits and monitors the location and characteristics of many vessels in U.S. and...

  17. 2011 Tanker Vessel Density

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Automatic Identification Systems (AIS) are a navigation safety device that transmits and monitors the location and characteristics of many vessels in U.S. and...

  18. 2013 Fishing Vessel Density

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Automatic Identification Systems (AIS) are a navigation safety device that transmits and monitors the location and characteristics of many vessels in U.S. and...

  19. LANL Robotic Vessel Scanning

    Energy Technology Data Exchange (ETDEWEB)

    Webber, Nels W. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2015-11-25

    Los Alamos National Laboratory in J-1 DARHT Operations Group uses 6ft spherical vessels to contain hazardous materials produced in a hydrodynamic experiment. These contaminated vessels must be analyzed by means of a worker entering the vessel to locate, measure, and document every penetration mark on the vessel. If the worker can be replaced by a highly automated robotic system with a high precision scanner, it will eliminate the risks to the worker and provide management with an accurate 3D model of the vessel presenting the existing damage with the flexibility to manipulate the model for better and more in-depth assessment.The project was successful in meeting the primary goal of installing an automated system which scanned a 6ft vessel with an elapsed time of 45 minutes. This robotic system reduces the total time for the original scope of work by 75 minutes and results in excellent data accumulation and transmission to the 3D model imaging program.

  20. Northeast Commercial Fishing Vessel Cost Survey

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Typically, commercial fishing businesses incur three major types of costs: fixed or annual costs; which are incurred annually irrespective of whether any fishing...

  1. Great Lakes Research Vessel Operations 1958-2016: Reference

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — The RVCAT database contains data that have been collected on various vessel operations on the Great Lakes and select connecting waterways. This section of Reference...

  2. Albatrosses following fishing vessels: how badly hooked are they on an easy meal?

    Directory of Open Access Journals (Sweden)

    José P Granadeiro

    Full Text Available Fisheries have major impacts on seabirds, both by changing food availability and by causing direct mortality of birds during trawling and longline setting. However, little is known about the nature and the spatial-temporal extent of the interactions between individual birds and vessels. By studying a system in which we had fine-scale data on bird movements and activity, and near real-time information on vessel distribution, we provide new insights on the association of a threatened albatross with fisheries. During early chick-rearing, black-browed albatrosses Thalassarche melanophris from two different colonies (separated by only 75 km showed significant differences in the degree of association with fisheries, despite being nearly equidistant to the Falklands fishing fleet. Most foraging trips from either colony did not bring tracked individuals close to vessels, and proportionally little time and foraging effort was spent near ships. Nevertheless, a few individuals repeatedly visited fishing vessels, which may indicate they specialise on fisheries-linked food sources and so are potentially more vulnerable to bycatch. The evidence suggests that this population has little reliance on fisheries discards at a critical stage of its nesting cycle, and hence measures to limit fisheries waste on the Patagonian shelf that also reduce vessel attractiveness and the risk of incidental mortality, would be of high overall conservation benefit.

  3. Albatrosses Following Fishing Vessels: How Badly Hooked Are They on an Easy Meal?

    Science.gov (United States)

    Granadeiro, José P.; Phillips, Richard A.; Brickle, Paul; Catry, Paulo

    2011-01-01

    Fisheries have major impacts on seabirds, both by changing food availability and by causing direct mortality of birds during trawling and longline setting. However, little is known about the nature and the spatial-temporal extent of the interactions between individual birds and vessels. By studying a system in which we had fine-scale data on bird movements and activity, and near real-time information on vessel distribution, we provide new insights on the association of a threatened albatross with fisheries. During early chick-rearing, black-browed albatrosses Thalassarche melanophris from two different colonies (separated by only 75 km) showed significant differences in the degree of association with fisheries, despite being nearly equidistant to the Falklands fishing fleet. Most foraging trips from either colony did not bring tracked individuals close to vessels, and proportionally little time and foraging effort was spent near ships. Nevertheless, a few individuals repeatedly visited fishing vessels, which may indicate they specialise on fisheries-linked food sources and so are potentially more vulnerable to bycatch. The evidence suggests that this population has little reliance on fisheries discards at a critical stage of its nesting cycle, and hence measures to limit fisheries waste on the Patagonian shelf that also reduce vessel attractiveness and the risk of incidental mortality, would be of high overall conservation benefit. PMID:21399696

  4. Inshore small-mesh trawling survey of the Cape south coast. Part 4 ...

    African Journals Online (AJOL)

    by echinoderms, polychaetes, fish and molluscs. There was little difference in the prey represented in the guts of fIsh taken from different areas although Echinocardium spp. were more abun- dant in fIsh taken west of Plettenberg Bay. The composition of the diet suggests that this fIsh is a fairly. Table 1 Prey of P. natalensis.

  5. Shelikof Strait Acoustic-Trawl Survey of Walleye Pollock (DY1002, ME70)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The Midwater Assessment and Conservation Engineering (MACE) program of the Alaska Fisheries Science Center (AFSC; NOAA National Marine Fisheries Service) conducted...

  6. Gulf of Alaska Acoustic-Trawl Survey of Walleye Pollock (DY1506, EK60)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The Midwater Assessment and Conservation Engineering (MACE) program of NOAA National Marine Fisheries Service (NMFS), Alaska Fisheries Science Center (AFSC)...

  7. Gulf of Alaska Acoustic-Trawl Survey of Walleye Pollock (DY1307, ME70)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The Midwater Assessment and Conservation Engineering (MACE) program of NOAA's National Marine Fisheries Service, Alaska Fisheries Science Center (AFSC) conducted an...

  8. Gulf of Alaska Acoustic-Trawl Survey of Walleye Pollock (DY1602, EK60)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The Midwater Assessment and Conservation Engineering (MACE) program of NOAA National Marine Fisheries Service (NMFS), Alaska Fisheries Science Center (AFSC)...

  9. Southeastern Aleutian Basin (Bogoslof Island) Acoustic-Trawl Survey of Walleye Pollock (DY1402, EK60)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The Midwater Assessment and Conservation Engineering (MACE) program of NOAA National Marine Fisheries Service (NMFS), Alaska Fisheries Science Center (AFSC)...

  10. AFSC/RACE/GAP/Kotwicki: Relative light intensity collected during bottom trawl surveys

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Assessing the effect of light intensity and light penetration on the distributionand behavior of walleye pollock (Gadus chalcogrammus) in the eastern Bering Sea and...

  11. 2015 Pollock Acoustic/Trawl Survey Gulf of Alaska EK60 Raw Data

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Scientists from the Midwater Assessment and Conservation Engineering (MACE) Program of the Alaska Fisheries Science Center's (AFSC) Resource Assessment and...

  12. Gulf of Alaska Acoustic-Trawl Survey of Walleye Pollock (DY1401, EK60)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The Midwater Assessment and Conservation Engineering (MACE) program of NOAA National Marine Fisheries Service (NMFS), Alaska Fisheries Science Center (AFSC)...

  13. AFSC/RACE/MACE: Results of 2012 Pollock Acoustic-Trawl Survey Bering Sea- DY1207

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Eastern Bering Sea shelf walleye pollock (Theragra chalcogramma) midwater abundance and distribution were assessed from Bristol Bay in the United States, to Cape...

  14. Eastern Bering Sea Acoustic-Trawl Survey of Walleye Pollock (DY1006, ME70)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The Midwater Assessment and Conservation Engineering (MACE) program of the Alaska Fisheries Science Center (AFSC; NOAA National Marine Fisheries Service) conducted...

  15. Gulf of Alaska Acoustic-Trawl Survey of Walleye Pollock (DY1403, EK60)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The Midwater Assessment and Conservation Engineering (MACE) program of NOAA National Marine Fisheries Service (NMFS), Alaska Fisheries Science Center (AFSC)...

  16. AFSC/RACE/MACE: Results of 2012 acoustic trawl survey Shelikof DY1203

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Scientists from the Midwater Assessment and Conservation Engineering (MACE) Program of the Alaska Fisheries Science Center (AFSC) Resource Assessment and...

  17. Inshore small-mesh trawling survey of the Cape south coast. Part 5 ...

    African Journals Online (AJOL)

    from Japan and Timor, especially in the overall granulation and the trilobed rostrum. The Japanese species, however, possesses more carapace areolations than does C. hirsutimana. The latter is very similar to Petalomera nodosa Sakai from. Japan, but lacks the epipods characteristic of this genus. Cryp- todromia sculpta ...

  18. Gulf of Alaska Acoustic-Trawl Survey of Walleye Pollock (DY1303, EK60)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The Midwater Assessment and Conservation Engineering (MACE) program of NOAA National Marine Fisheries Service (NMFS), Alaska Fisheries Science Center (AFSC)...

  19. AFSC/RACE/MACE: Results of 2014 Pollock Acoustic-Trawl Survey Bering Sea- DY1407

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Eastern Bering Sea shelf walleye pollock (Gadus chalcogrammus) midwater abundance and distribution were assessed from Bristol Bay in the United States, to Cape...

  20. Gulf of Alaska Acoustic-Trawl Survey of Walleye Pollock (DY1506, ME70)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The Midwater Assessment and Conservation Engineering (MACE) program of NOAA National Marine Fisheries Service (NMFS), Alaska Fisheries Science Center (AFSC)...

  1. Shumagin Islands Acoustic-Trawl Survey of Walleye Pollock (DY1302, ME70)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The Midwater Assessment and Conservation Engineering (MACE) program of NOAA's National Marine Fisheries Service, Alaska Fisheries Science Center (AFSC), conducted an...

  2. Acoustic-Trawl Survey of Walleye Pollock in the Gulf of Alaska (DY1604, EK60)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The Midwater Assessment and Conservation Engineering (MACE) program of NOAA National Marine Fisheries Service (NMFS), Alaska Fisheries Science Center (AFSC)...

  3. AFSC/RACE/MACE: Results of 2013 acoustic trawl survey Gulf of Alaska DY1307

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Scientists from the Midwater Assessment and Conservation Engineering (MACE) Program of the Alaska Fisheries Science Center (AFSC) Resource Assessment and...

  4. AFSC/RACE/MACE: Results of 2014 Pollock Acoustic-Trawl Survey Shelikof- DY1403

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The Midwater Assessment and Conservation Engineering (MACE) Program of the Alaska Fisheries Science Center's (AFSC) Resource Assessment and Conservation Engineering...

  5. AFSC/RACE/MACE: Results of 2013 Pollock Acoustic/Trawl Survey Shelikof 201303

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Scientists from the Midwater Assessment and Conservation Engineering (MACE) Program of the Alaska Fisheries Science Center's (AFSC) Resource Assessment and...

  6. AFSC/RACE/MACE: Results of 2008 pollock acoustic trawl survey Shelikof DY0803

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Scientists from the Midwater Assessment and Conservation Engineering (MACE) Program of the Alaska Fisheries Science Center's (AFSC) Resource Assessment and...

  7. AFSC/RACE/MACE: Results of 2015 acoustic trawl survey Shelikof DY1503

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Scientists from the Midwater Assessment and Conservation Engineering (MACE) Program of the Alaska Fisheries Science Center's (AFSC) Resource Assessment and...

  8. Acoustic-Trawl Survey of Walleye Pollock in the Gulf of Alaska (DY1503, EK60)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The Midwater Assessment and Conservation Engineering (MACE) program of NOAA National Marine Fisheries Service (NMFS), Alaska Fisheries Science Center (AFSC)...

  9. Gulf of Alaska Acoustic-Trawl Surveys of Walleye Pollock (DY1201, EK60)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The Midwater Assessment and Conservation Engineering (MACE) program of NOAA National Marine Fisheries Service (NMFS), Alaska Fisheries Science Center (AFSC)...

  10. Southeastern Aleutian Basin (Bogoslof Island) Acoustic-Trawl Survey of Walleye Pollock (DY1202, EK60)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The Midwater Assessment and Conservation Engineering (MACE) program of NOAA National Marine Fisheries Service (NMFS), Alaska Fisheries Science Center (AFSC)...

  11. AFSC/ABL: Gulf of Alaska Diel Trawl Survey, 2005-2006

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Diel epipelagic sampling for juvenile Pacific salmon (Oncorhynchus spp.), rockfish (Sebastes spp.), sablefish (Anoplopoma fimbria), and associated species was...

  12. Gulf of Alaska Acoustic-Trawl Survey of Walleye Pollock (DY1302, EK60)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The Midwater Assessment and Conservation Engineering (MACE) program of NOAA National Marine Fisheries Service (NMFS), Alaska Fisheries Science Center (AFSC)...

  13. Southeastern Aleutian Basin (Bogoslof Island) Acoustic-Trawl Survey of Walleye Pollock (DY1603, EK60)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The Midwater Assessment and Conservation Engineering (MACE) program of NOAA National Marine Fisheries Service (NMFS), Alaska Fisheries Science Center (AFSC)...

  14. Trawl survey data are applied in fish stock assessment mainly to ...

    African Journals Online (AJOL)

    denise

    ingly, an independent measurement of abundance can be made, against ... in herding at different in situ levels of illumination. (Glass and Wardle .... to compensate for downward rounding of all length measurements. If both species of hake were present their length frequencies were pooled, using the catch rate of each ...

  15. Gulf of Alaska Acoustic-Trawl Surveys of Walleye Pollock (DY1203, EK60)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The Midwater Assessment and Conservation Engineering (MACE) program of NOAA National Marine Fisheries Service (NMFS), Alaska Fisheries Science Center (AFSC)...

  16. Acoustic-Trawl Survey of Walleye Pollock in the Gulf of Alaska (OD0501, EK60)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The Midwater Assessment and Conservation Engineering (MACE) program of NOAA National Marine Fisheries Service (NMFS), Alaska Fisheries Science Center (AFSC)...

  17. Shumagin Islands Acoustic-Trawl Survey of Walleye Pollock (DY1001, ME70)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The Midwater Assessment and Conservation Engineering (MACE) program of the Alaska Fisheries Science Center (AFSC; NOAA National Marine Fisheries Service) conducted...

  18. Gulf of Alaska Acoustic-Trawl Survey of Walleye Pollock (DY1307, EK60)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The Midwater Assessment and Conservation Engineering (MACE) program of NOAA National Marine Fisheries Service (NMFS), Alaska Fisheries Science Center (AFSC)...

  19. Acoustic-Trawl Survey of Walleye Pollock in the Gulf of Alaska (MF0309, EK500)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The Midwater Assessment and Conservation Engineering (MACE) program of NOAA National Marine Fisheries Service (NMFS), Alaska Fisheries Science Center (AFSC)...

  20. AFSC/ABL: Blackspotted and rougheye rockfish genetics and age data from RACE trawl surveys

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This data set contains field and genetic identification of rougheye (Sebastes aleutianus) and blackspotted (Sebastes melanostictus) rockfish collected during AFSC...

  1. Inshore small-mesh trawling survey of the Cape south coast. Part 1 ...

    African Journals Online (AJOL)

    Figure 1 Stations sampled by the R.V. Thomas B. Davie between Mossel Bay and Algoa Bay. ... results. Selection of stations. Sampling stations were selected in the following areas: (i) Off the mouths and beaches adjacent to estuarine systems in which the juvenile ... estuarine-associated species because wave action is less.

  2. AFSC/RACE/MACE: Results of 2007 Pollock Acoustic-Trawl Survey Bering Sea- DY0707

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Eastern Bering Sea shelf walleye pollock (Theragra chalcogramma) abundance and distribution in midwater were assessed between 2 June and 30 July 2007 using echo...

  3. AFSC/RACE/MACE: Results of 2009 Pollock Acoustic-Trawl Survey Bering Sea- DY0909

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Eastern Bering Sea shelf walleye pollock (Theragra chalcogramma) abundance and distribution in midwater were assessed between 9 June and 7 August 2009 using...

  4. AFSC/RACE/MACE: Results of 2010 Pollock Acoustic-Trawl Survey Bering Sea- DY1006

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Eastern Bering Sea shelf walleye pollock (Theragra chalcogramma) abundance and distribution in midwater were assessed between 5 June and 7 August 2010 using...

  5. Gulf of Alaska Acoustic-Trawl Surveys of Walleye Pollock (DY1002, EK60)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The Midwater Assessment and Conservation Engineering (MACE) program of NOAA National Marine Fisheries Service (NMFS), Alaska Fisheries Science Center (AFSC)...

  6. AFSC/RACE/MACE: Results of 2011 acoustic trawl survey Gulf of Alaska DY1103

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Scientists from the Midwater Assessment and Conservation Engineering (MACE) Program of the Alaska Fisheries Science Center (AFSC) Resource Assessment and...

  7. AFSC/RACE/MACE: Results of 2012 acoustic trawl survey Bogoslof DY1202

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Scientists from the Midwater Assessment and Conservation Engineering (MACE) program of the Alaska Fisheries Science Center (AFSC) Resource Assessment and...

  8. NEFSC Small Pelagics Acoustic/Midwater Trawl Survey (DE9903, EK500)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The small pelagics cruise will map the distribution of small pelagic species such as Atlantic mackerel, Atlantic herring, silver hake, butterfish, and squid, in the...

  9. NEFSC Small Pelagics Acoustic/Midwater Trawl Survey (DE0201, EK500)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The small pelagics cruise will map the distribution of small pelagic species such as Atlantic mackerel, Atlantic herring, silver hake, butterfish, and squid, in the...

  10. NEFSC Small Pelagics Acoustic/Midwater Trawl Survey (DE0505, EK500)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The small pelagics cruise will map the distribution of small pelagic species such as Atlantic mackerel, Atlantic herring, silver hake, butterfish, and squid, in the...

  11. NEFSC Small Pelagics Acoustic/Midwater Trawl Survey (DE0002, EK500)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The small pelagics cruise will map the distribution of small pelagic species such as Atlantic mackerel, Atlantic herring, silver hake, butterfish, and squid, in the...

  12. NEFSC Small Pelagics Acoustic/Midwater Trawl Survey (DE0302, EK500)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The small pelagics cruise will map the distribution of small pelagic species such as Atlantic mackerel, Atlantic herring, silver hake, butterfish, and squid, in the...

  13. NEFSC Small Pelagics Acoustic/Midwater Trawl Survey (DE0101, EK500)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The small pelagics cruise will map the distribution of small pelagic species such as Atlantic mackerel, Atlantic herring, silver hake, butterfish, and squid, in the...

  14. AFSC/REFM: Acoustic trawl cooperative survey near Shumagin Islands 2007-2013

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — In May of 2006, scientists from the Alaska Fisheries Science Center participated in a pilot outreach program in Sand Point, Alaska. At the meetings, fishermen raised...

  15. Shelikof Strait Acoustic-Trawl Survey of Walleye Pollock (DY1303, ME70)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The Midwater Assessment and Conservation Engineering (MACE) program of NOAA's National Marine Fisheries Service, Alaska Fisheries Science Center (AFSC) conducted an...

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

    Science.gov (United States)

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

    Science.gov (United States)

    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.

  18. Enhancing supply vessel safety

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2002-07-01

    A supply-vessel bridge installation consists of a navigating bridge and a control position aft, from which operators control the ship when close to rigs or platforms, and operate winches and other loading equipment. The international Convention for Safety of I Ale at Sea (SOLAS) does not regulate the layout, so design varies to a large degree, often causing an imperfect working environment. As for other types of ships, more than half the offshore service vessel accidents at sea are caused by bridge system failures. A majority can be traced back to technical design, and operational errors. The research and development project NAUT-OSV is a response to the offshore industry's safety concerns. Analysis of 24 incidents involving contact or collision between supply vessels and offshore installations owned or operated by Norwegian companies indicated that failures in the bridge system were often the cause.

  19. Improving the selectivity of beam trawls in The Netherlands: the effect of large mesh top panels on the catch rates of sole, plaice, cod and whiting

    NARCIS (Netherlands)

    Marlen, van B.

    2003-01-01

    This paper presents the results of experiments aimed to improve the selectivity of beam trawls in the North Sea for roundfish whilst minimizing losses on target flatfish. Large-meshed top panels were designed for the tickler chain type of beam trawls used in this fishery. The design process involved

  20. Bell-shaped size selection in a bottom trawl: A case study for Nephrops directed fishery with reduced catches of cod

    DEFF Research Database (Denmark)

    Lövgren, Johan; Herrmann, Bent; Feekings, Jordan P.

    2016-01-01

    and size selectivity have motivated the development of selective systems in trawl fisheries that utilize more than one selective device simultaneously. An example can be found in the Swedish demersal trawl fishery targeting Norway lobster (Nephrops norvegicus), which simultaneously aims at avoiding catches...

  1. Improving the size- and species selectivity of cod (Gadus morhua) in demersal mixed-species trawl fisheries

    DEFF Research Database (Denmark)

    Krag, Ludvig Ahm

    different species, including cod, are caught together. Demersal trawling is the predominant fishing method in Denmark, as measured by both catch value and volume. Demersal trawls also account for the highest discard rates of juvenile fish, including cod. The focus of this work was on improving...... the selectivity of demersal trawling with regard to cod. This Ph.D. thesis consists of a review and four supporting papers (1-4). Two main techniques are used to aid fish in escaping from fishing gear. The first technique involves a process of mechanical sorting based on fish size and the second is based...... of this study was to improve the size selection for cod in the fisheries directed towards Nephrops. Paper 2 describes a new methodology, tools, and software that have been developed and used to measure the morphological parameters that determine the ability of cod to penetrate different mesh types, sizes...

  2. Discards Management: reducing plaice discards via beam-trawl effort reallocations

    OpenAIRE

    Uhlmann, S.S.; Poos, J.J.; Aarts, G.M.; Helmond, van, A.T.M.

    2012-01-01

    Ways to improve the well-being and likewise to reduce the number of fish returned to sea as unwanted waste (‘discards’) have received major attention by the Dutch commercial beam-trawl fishing sector, and responsible ministries. There are various options to achieve this: make the gear more selective for the right sizes and species; allow more and smaller species to be landed; and protect spawning and nursery areas. While other research is focussed on improving gear selectivity, this report sh...

  3. Discarding Discards: Identification of influential factors and possible mitigation tools in demersal trawl fisheries

    DEFF Research Database (Denmark)

    Feekings, Jordan P.

    in high discard rates/ratios may prove beneficial not only to the economic viability of the fishery but also to the biological functioning of the ecosystem. The present Ph.D. thesis, titled “Discarding Discards: Identification of influential factors and possible mitigation tools in demersal trawl...... an examination of the efficiency of technical regulations currently in force and retrospective analyses of the efficiency of such measures in the past. The thesis consists of a review and 4 papers. Paper I is an investigation of the factors that can potentially influence the discarding of commercial species...

  4. GOLD PRESSURE VESSEL SEAL

    Science.gov (United States)

    Smith, A.E.

    1963-11-26

    An improved seal between the piston and die member of a piston-cylinder type pressure vessel is presented. A layer of gold, of sufficient thickness to provide an interference fit between the piston and die member, is plated on the contacting surface of at least one of the members. (AEC)

  5. Network of endocardial vessels.

    Science.gov (United States)

    Lee, Byung-Cheon; Kim, Hong Bae; Sung, Baeckkyoung; Kim, Ki Woo; Sohn, Jamin; Son, Boram; Chang, Byung-Joon; Soh, Kwang-Sup

    2011-01-01

    Although there have been reports on threadlike structures inside the heart, they have received little attention. We aimed to develop a method for observing such structures and to reveal their ultrastructures. An in situ staining method, which uses a series of procedures of 0.2-0.4% trypan blue spraying and washing, was applied to observe threadlike structures on the surfaces of endocardia. The threadlike structures were isolated and observed by using confocal laser scanning microscopy (CLSM) and transmission electron microscopy (TEM). Networks of endocardial vessels (20 μm in thickness) with expansions (40-100 μm in diameter) were visualized; they were movable on the endocardium of the bovine atrium and ventricle. CLSM showed that (1) rod-shaped nuclei were aligned along the longitudinal direction of the endocardial vessel and (2) there were many cells inside the expansion. TEM on the endocardial vessel revealed that (1) there existed multiple lumens (1-7 μm in diameter) and (2) the extracellular matrices mostly consisted of collagen fibers, which were aligned along the longitudinal direction of the endocardial vessel or were locally organized in reticular structures. We investigated the endocardial circulatory system in bovine cardiac chambers and its ultrastructures, such as nucleic distributions, microlumens, and collagenous extracellular matrices. Copyright © 2011 S. Karger AG, Basel.

  6. Pressurized Vessel Slurry Pumping

    Energy Technology Data Exchange (ETDEWEB)

    Pound, C.R.

    2001-09-17

    This report summarizes testing of an alternate ''pressurized vessel slurry pumping'' apparatus. The principle is similar to rural domestic water systems and ''acid eggs'' used in chemical laboratories in that material is extruded by displacement with compressed air.

  7. 77 FR 36998 - Proposed Information Collection; Comment Request; Mandatory Shrimp Vessel and Gear...

    Science.gov (United States)

    2012-06-20

    ... Information Collection; Comment Request; Mandatory Shrimp Vessel and Gear Characterization Survey AGENCY... for the Gulf Shrimp Vessel and Gear Characterization Form may be found at 50 CFR 622.5(a)(1)(iii)(C... shrimp must complete an annual Gulf Shrimp Vessel and Gear Characterization Form. The form will be...

  8. Effort dynamics in a fisheries bioeconomic model: A vessel level approach through Game Theory

    Directory of Open Access Journals (Sweden)

    Gorka Merino

    2007-09-01

    Full Text Available Red shrimp, Aristeus antennatus (Risso, 1816 is one of the most important resources for the bottom-trawl fleets in the northwestern Mediterranean, in terms of both landings and economic value. A simple bioeconomic model introducing Game Theory for the prediction of effort dynamics at vessel level is proposed. The game is performed by the twelve vessels exploiting red shrimp in Blanes. Within the game, two solutions are performed: non-cooperation and cooperation. The first is proposed as a realistic method for the prediction of individual effort strategies and the second is used to illustrate the potential profitability of the analysed fishery. The effort strategy for each vessel is the number of fishing days per year and their objective is profit maximisation, individual profits for the non-cooperative solution and total profits for the cooperative one. In the present analysis, strategic conflicts arise from the differences between vessels in technical efficiency (catchability coefficient and economic efficiency (defined here. The ten-year and 1000-iteration stochastic simulations performed for the two effort solutions show that the best strategy from both an economic and a conservationist perspective is homogeneous effort cooperation. However, the results under non-cooperation are more similar to the observed data on effort strategies and landings.

  9. Otter trawls in Greece: Landing profiles and potential mιtiers

    Directory of Open Access Journals (Sweden)

    S. KATSANEVAKIS

    2010-02-01

    Full Text Available A fleet of 326 bottom trawlers operate in Greek Seas and their landings represent approximately 30% of the total fish production in Greece. In this study, otter trawl landings data were analyzed in order to identify potential métiers. Landings data between 2002 and 2006 were used, collected from 42 ports in the Aegean and East Ionian Sea. A three-step procedure was applied to identify potential métiers: the first step involved a factorial analysis of the log-transformed landings profiles, the second step a classification of the factorial coordinates, and the third step a further aggregation of clusters based on expert knowledge. In all, six potential métiers were identified in the Aegean Sea, and five in the Ionian Sea. The most important target species were European hake (Merluccius merluccius, deepwater pink shrimp (Parapenaeus longirostris, red mullet (Mullus barbatus, caramote prawn (Melicertus kerathurus, picarel (Spicara smaris, cephalopods, bogue (Boops boops, anglers (Lophiusspp., and Norway lobster (Nephrops norvegicus. Otter trawls in Greece use more or less the same gear with minor modification, and métier selection is basically reflected as a choice of geographical sub-area and hauling depth. The limitations of using landings profiles to identify métiers and the need for further verification are discussed.

  10. Trawling disturbance on benthic ecosystems and consequences on commercial species: a northwestern Mediterranean case study

    Directory of Open Access Journals (Sweden)

    Alba Muntadas

    2014-03-01

    Full Text Available Trawling is known to disturb benthic communities and habitats, which may in turn indirectly affect populations of commercial species that live in close association with the seabed. The degree of impact on both benthic communities and demersal species depends on the fishing effort level. This may vary over the year because of the fleet dynamics, which are in turn normally driven by the main target species’ life cycle. In this study we describe changes in benthic functional components of a northwestern Mediterranean fishing ground that represents a recruitment area for an important target species (red mullet, Mullus barbatus. This fishing ground experiences a varying intensity of fishing effort over the year and benthic functional components under different levels of trawling were compared with an unfished, control area. Traits related to sexual maturity and life span for infauna and body size and life span for epifauna were found to vary with fishing activity. Potential effects of these changes on ecological functioning and the impact on red mullet population are discussed. The development of fisheries management plans under an ecosystem based fisheries management (EBFM requires the links between target species and benthic communities’ disturbance due to fishing practices to be explicitly considered.

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

    Directory of Open Access Journals (Sweden)

    Aurélie Foveau

    Full Text Available 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.

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

    Science.gov (United States)

    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.

  13. Determining the impacts of trawling on benthic function in European waters : a biological traits approach

    DEFF Research Database (Denmark)

    Bolam, Stefan; Kenny, Andrew; Garcia, Clement

    One of the most widespread yet manageable pressures we impose on the seabed is disturbance of the substrate by towed demersal fishing gear (bottom trawling and dredging). Over the past forty to fifty years, many studies have been conducted specifically aiming to understand the impacts of such fis......One of the most widespread yet manageable pressures we impose on the seabed is disturbance of the substrate by towed demersal fishing gear (bottom trawling and dredging). Over the past forty to fifty years, many studies have been conducted specifically aiming to understand the impacts...... the functional impacts of this activity (as opposed to impacts on the structure of benthic assemblages) has only recently been attempted. Advances in the application of biological traits analysis (BTA) wherein the assemblages are described in terms of their life history, behavioural and morphological...... on benthic ecosystem functioning over much larger spatial scales than previously undertaken. Biological traits information from 887 stations across European waters (Norwegian, UK, Belgian, Dutch, Danish waters, the Mediterranean and Black Sea) were analysed to: i) quantify the relationships between infaunal...

  14. Hawaii Abandoned Vessel Inventory, Kauai

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — NOAA Abandoned Vessel Project Data for Kauai. Abandoned vessels pose a significant threat to the NOAA Trust resources through physical destruction of coral habitats...

  15. CNMI Abandoned Vessel Inventory, Tinian

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — NOAA Abandoned Vessel Project Data for Tinian. Abandoned vessels pose a significant threat to the NOAA Trust resources through physical destruction of coral habitats...

  16. Puerto Rico Abandoned Vessel Inventory

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — NOAA Abandoned Vessel Project Data for Puerto Rico. Abandoned vessels pose a significant threat to the NOAA Trust resources through physical destruction of coral...

  17. American Samoa Abandoned Vessel Inventory

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — NOAA Abandoned Vessel Project Data for American Samoa. Abandoned vessels pose a significant threat to the NOAA Trust resources through physical destruction of coral...

  18. Hawaii Abandoned Vessel Inventory, Oahu

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — NOAA Abandoned Vessel Project Data for Oahu, Hawaii. Abandoned vessels pose a significant threat to the NOAA Trust resources through physical destruction of coral...

  19. Hawaii Abandoned Vessel Inventory, Molokai

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — NOAA Abandoned Vessel Project Data for Molokai, Hawaii. Abandoned vessels pose a significant threat to the NOAA Trust resources through physical destruction of coral...

  20. CNMI Abandoned Vessel Inventory, Rota

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — NOAA Abandoned Vessel Project Data for Rota. Abandoned vessels pose a significant threat to the NOAA Trust resources through physical destruction of coral habitats...

  1. Hawaii Abandoned Vessel Inventory, Lanai

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — NOAA Abandoned Vessel Project Data for Lanai. Abandoned vessels pose a significant threat to the NOAA Trust resources through physical destruction of coral habitats...

  2. CNMI Abandoned Vessel Inventory, Saipan

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — NOAA Abandoned Vessel Project Data for Saipan. Abandoned vessels pose a significant threat to the NOAA Trust resources through physical destruction of coral habitats...

  3. Hawaii Abandoned Vessel Inventory, Maui

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — NOAA Abandoned Vessel Project Data for Maui. Abandoned vessels pose a significant threat to the NOAA Trust resources through physical destruction of coral habitats...

  4. Vessels in Transit - Web Tool

    Data.gov (United States)

    Department of Transportation — A web tool that provides real-time information on vessels transiting the Saint Lawrence Seaway. Visitors may sort by order of turn, vessel name, or last location in...

  5. Monitoring the magnitude of marine vessel infestation by non-indigenous ascidians in the Mediterranean.

    Science.gov (United States)

    Gewing, Mey-Tal; Shenkar, Noa

    2017-08-15

    Invasive ascidians (Chordata, Tunicata) are dominant nuisance organisms. The current study investigated the role of marine vessels in their dispersal and introduction. An examination of 45 dry-docked marine vessels, comprising recreational, commercial, and military craft, in five Israeli shipyards along the Mediterranean coast, revealed non-indigenous ascidians (NIA) on every second vessel investigated. Military vessels featured the highest ascidian abundance and richness, potentially related to their maintenance routine. Niche areas on the vessels such as sea chests and the propeller exhibited the highest occurrence of ascidians. Overall, these findings provide strong evidence that marine vessels play an acute role in NIA introduction and dispersal, with military vessels and niche areas on all the vessels being more susceptible to serving as vectors. A discovery of a new introduced species during the surveys suggests that the monitoring of marine vessels can serve as an effective tool for the early detection of NIA. Copyright © 2017 Elsevier Ltd. All rights reserved.

  6. Pressure vessel design manual

    Energy Technology Data Exchange (ETDEWEB)

    Moss, D.R.

    1987-01-01

    The first section of the book covers types of loadings, failures, and stress theories, and how they apply to pressure vessels. The book delineates the procedures for designing typical components as well as those for designing large openings in cylindrical shells, ring girders, davits, platforms, bins and elevated tanks. The techniques for designing conical transitions, cone-cylinder intersections, intermediate heads, flat heads, and spherically dished covers are also described. The book covers the design of vessel supports subject to wind and seismic loads and one section is devoted to the five major ways of analyzing loads on shells and heads. Each procedure is detailed enough to size all welds, bolts, and plate thicknesses and to determine actual stresses.

  7. Large vessel vasculitides

    OpenAIRE

    Morović-Vergles, Jadranka; Pukšić, Silva; Gudelj Gračanin, Ana

    2013-01-01

    Large vessel vasculitis includes Giant cell arteritis and Takayasu arteritis. Giant cell arteritis is the most common form of vasculitis affect patients aged 50 years or over. The diagnosis should be considered in older patients who present with new onset of headache, visual disturbance, polymyalgia rheumatica and/or fever unknown cause. Glucocorticoides remain the cornerstone of therapy. Takayasu arteritis is a chronic panarteritis of the aorta ant its major branches presenting commonly in y...

  8. Very Versatile Vessel

    Science.gov (United States)

    2009-09-01

    data. This source provides information on aluminum hydrofoil vessels without the added weight of foil structures. The composite armor around the...seating compartment. The sides should also limit wave splash on the deck. The freeboard should contribute reserve buoyancy , increasing large-angle and...Resistance, Powering, and Propulsion Savitsky’s Method Since model testing data or other reliable performance data was unavailable for the proposed

  9. Similar effects of bottom trawling and natural disturbance on composition and function of benthic communities across habitats

    DEFF Research Database (Denmark)

    van Denderen, Pieter Daniël; Bolam, S.G.; Hiddink, J.G.

    2015-01-01

    communities in similar ways. Both sources of disturbance caused declines in long-living, hard-bodied (exoskeleton) and suspension-feeding organisms. Given these similar impacts, there was no detectable trawling effect on communities exposed to high natural disturbance. Conversely, in 3 out of 5 areas with low...

  10. 78 FR 17340 - Control Date for Qualifying Landings History in the Western Gulf of Alaska Trawl Groundfish...

    Science.gov (United States)

    2013-03-21

    ... history for an allocation-based management or catch share program in the Western Gulf of Alaska (GOA... future management measures in determining how to credit landings and permit history acquired before or... Landings History in the Western Gulf of Alaska Trawl Groundfish Fisheries AGENCY: National Marine Fisheries...

  11. 77 FR 75966 - Control Date for Qualifying Landings History in the Central Gulf of Alaska Trawl Groundfish...

    Science.gov (United States)

    2012-12-26

    ... 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. We... Landings History in the Central Gulf of Alaska Trawl Groundfish Fisheries AGENCY: National Marine Fisheries...

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

    NARCIS (Netherlands)

    Denderen, van P.D.; Kooten, van T.; Rijnsdorp, A.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

  13. A simulation-based attempt to quantify the morphological component of size selection of Nephrops norvegicus in trawl codends

    DEFF Research Database (Denmark)

    Frandsen, Rikke; Herrmann, Bent; Madsen, Niels

    2010-01-01

    The selectivity for Nephrops (Nephrops norvegicus) in trawl codends generally is poor and the lack of steepness of the selection curve results in high discard rates and/or loss of legal-sized catch. This poor codend selectivity often is attributed to the irregular shape of Nephrops, which to some...

  14. Influence of fleet renewal and trawl development on landings per unit effort of the Danish northern shrimp (Pandalus borealis) fishery

    DEFF Research Database (Denmark)

    Eigaard, Ole Ritzau; Munch-Petersen, Sten

    2011-01-01

    Recent stock assessments of the Pandalus stock in the Skagerrak (ICES Division IIIa) and the Norwegian Deep (Division IVa east) have relied largely on a time-series of landings per unit effort (lpue) calculated from Danish logbook data. Because of fleet renewal and trawl-size changes...

  15. Vessel Traffic Services.

    Science.gov (United States)

    1982-12-01

    Yorker" articles titled Silent Spring by Rachel Carson in 1963 produced a unifying effect, "the sort of rallying point of the movement to protect the...6232, 92d Cong., 1st. sess., 1971, p. 2. 15. Carson , Rachel L. , The Sea Around Us, New York: Oxford Univesity Press, 195-, p. IV. 16. U.S., Congress...Government Printing Office, 1974. 63. Buhler, L. and Geiger, J., Vessel Traffic Data Extraction MethodoloqX, Silver Spring , Maryland, O6erFae-tns

  16. Vanishing corneal vessels

    Science.gov (United States)

    Nicholson, Luke; Chana, Rupinder

    2013-01-01

    We wish to highlight the importance of acknowledging the accompanying effects of topical phenylephrine drops on the eye other than its intended mydriasis. We reported a case of a 92-year-old woman with a corneal graft who was noted to have superficial corneal vascularisation which was not documented previously. After the instillation of topical tropicamide 1% and phenylephrine 2.5%, for funduscopy, the corneal vascularisation was not visible. When reassessed on another visit, tropicamide had no effect on the vessels and only phenylephrine did. We wish to highlight that when reviewing patients in cornea clinics, instilling phenylephrine prior to being seen may mask important corneal vascularisation. PMID:24121816

  17. 46 CFR 289.2 - Vessels included.

    Science.gov (United States)

    2010-10-01

    ... CONSTRUCTION-DIFFERENTIAL SUBSIDY VESSELS, OPERATING-DIFFERENTIAL SUBSIDY VESSELS AND OF VESSELS SOLD OR ADJUSTED UNDER THE MERCHANT SHIP SALES ACT 1946 § 289.2 Vessels included. Vessels subject to the provisions of this part are: (a) All vessels which may in the future be constructed or sold with construction...

  18. Escape windows to improve the size selectivity in the Baltic cod trawl fishery

    DEFF Research Database (Denmark)

    Madsen, Niels; Holst, René; Foldager, L.

    2002-01-01

    A rapid decrease of the stock of Baltic cod (Gadus morhua) has provided the incentive to improve the size selectivity in the trawl fishery. Use of escape windows is permitted in the legislation to give means of improving the size selectivity of cod as an alternative to a traditional standard codend....... The history of the use of escape windows in the Baltic Sea cod fishery is reviewed. The present escape windows do not function optimally. The objective of this new experiment was to compare an improved design of escape window, which is placed in the upper panel, with that of standard codend. Three standard...... tool to improve the size selectivity in the Baltic cod fishery is discussed. (C) 2002 Elsevier Science B.V. All rights reserved....

  19. Blood flow reprograms lymphatic vessels to blood vessels.

    Science.gov (United States)

    Chen, Chiu-Yu; Bertozzi, Cara; Zou, Zhiying; Yuan, Lijun; Lee, John S; Lu, MinMin; Stachelek, Stan J; Srinivasan, Sathish; Guo, Lili; Vicente, Andres; Vincente, Andres; Mericko, Patricia; Levy, Robert J; Makinen, Taija; Oliver, Guillermo; Kahn, Mark L

    2012-06-01

    Human vascular malformations cause disease as a result of changes in blood flow and vascular hemodynamic forces. Although the genetic mutations that underlie the formation of many human vascular malformations are known, the extent to which abnormal blood flow can subsequently influence the vascular genetic program and natural history is not. Loss of the SH2 domain-containing leukocyte protein of 76 kDa (SLP76) resulted in a vascular malformation that directed blood flow through mesenteric lymphatic vessels after birth in mice. Mesenteric vessels in the position of the congenital lymphatic in mature Slp76-null mice lacked lymphatic identity and expressed a marker of blood vessel identity. Genetic lineage tracing demonstrated that this change in vessel identity was the result of lymphatic endothelial cell reprogramming rather than replacement by blood endothelial cells. Exposure of lymphatic vessels to blood in the absence of significant flow did not alter vessel identity in vivo, but lymphatic endothelial cells exposed to similar levels of shear stress ex vivo rapidly lost expression of PROX1, a lymphatic fate-specifying transcription factor. These findings reveal that blood flow can convert lymphatic vessels to blood vessels, demonstrating that hemodynamic forces may reprogram endothelial and vessel identity in cardiovascular diseases associated with abnormal flow.

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

    Directory of Open Access Journals (Sweden)

    Finlay N Thompson

    Full Text Available 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.

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

    Science.gov (United States)

    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 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.

  2. First Receiver and Shorebased Processor Data - Economic Data Collection for Monitoring the Economic Effects of the West Coast Groundfish Trawl Rationalization Program

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This project was initiated in response to regulation 50 CFR 660.114, which mandates that economic data be collected from every participant in the trawl...

  3. Catcher Processor Cost Earnings Data - Economic Data Collection for Monitoring the Economic Effects of the West Coast Groundfish Trawl Rationalization Program

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This project was initiated in response to regulation 50 CFR 660.114, which mandates that economic data be collected from every participant in the trawl...

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

    Science.gov (United States)

    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

  5. The vessel fluence; Fluence cuve

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2001-07-01

    This book presents the proceedings of the technical meeting on the reactors vessels fluence. They are grouped in eight sessions: the industrial context and the stakes of the vessels control; the organization and the methodology for the fluence computation; the concerned physical properties; the reference computation methods; the fluence monitoring in an industrial context; vessels monitoring under irradiation; others methods in the world; the research and development programs. (A.L.B.)

  6. Modified otter trawl legs to reduce damage and mortality of benthic organisms in North East Atlantic fisheries (Bay of Biscay)

    Science.gov (United States)

    Guyonnet, B.; Grall, J.; Vincent, B.

    2008-07-01

    Despite a consensus about the significant damages to marine benthos and commercial fish stocks induced by mobile fishing gear, the extent and intensity of this practice have currently grown all over the world. The main problems of fisheries management are the capture and killing of juvenile and undersized fish and thus restrictions mainly concern mesh size in cod-end. However another recurrent problem and non-negligible is the by-catch of undersize commercial fish and of non-target species. Hence, regulations to reduce such by-catch have formed a part of fisheries management techniques since the early 20th century. As a consequence, successful developments and technical modification have been used to reduce capture of undersized fish and discards (i.e. mesh size, separator panels, and sorting grids) in the last decades. Technical modification concerning reduction of damage and mortality to benthic communities are less documented. Most of the tentative to replace tickler chain, panels or legs by other systems have failed, while results showed a decrease in non-target catch, and a decrease in commercial catch was observed. This paper presents fishing experiments with modified otter trawl aimed at reducing discard rates and direct mortality of benthic infauna and epifauna without affecting the level of landings (i.e. a comparison of environmental effects caused by a conventional otter trawl compared to a modified otter trawl with enlighten experimental legs). Catch composition, by-catch and short-term effects to macro- and megafauna communities of both fishing gear (conventional and modified) were investigated. Results show that no differences for commercial catch biomass or for benthic communities' structure were observed. Moreover, by-catch analysis showed no difference while significant higher damage and direct mortality were observed for target and non-target species caught by the normal otter trawl compared to those caught by the modified one. Consequently

  7. Analysis and standardization of landings per unit effort of red shrimp Aristeus antennatus from the trawl fleet of Barcelona (NW Mediterranean

    Directory of Open Access Journals (Sweden)

    Valeria Mamouridis

    2014-03-01

    Full Text Available Monthly landings and effort data from the Barcelona trawl fleet (NW Mediterranean were selected to analyse and standardize the landings per unit effort (LPUE of the red shrimp (Aristeus antennatus using generalized additive models. The dataset covers a span of 15 years (1994-2008 and consists of a broad spectrum of predictors: fleet-dependent (e.g. number of trips performed by vessels and their technical characteristics, such as the gross registered tonnage, temporal (inter- and intra-annual variability, environmental (North Atlantic Oscillation [NAO] index and economic (red shrimp and fuel prices variables. All predictors individually have an impact on LPUE, though some of them lose their predictive power when considered jointly. That is the case of the NAO index. Our results show that six variables from the whole set can be incorporated into a global model with a total explained deviance (ED of 43%. We found that the most important variables were effort-related predictors (trips, tonnage, and groups with a total ED of 20.58%, followed by temporal variables, with an ED of 13.12%, and finally the red shrimp price as an economic predictor with an ED of 9.30%. Taken individually, the main contributing variable was the inter-annual variability (ED=12.40%. This high ED value suggests that many factors correlated with inter-annual variability, such as environmental factors (the NAO in specific years and fuel price, could in turn affect LPUE variability. The standardized LPUE index with the effort variability removed was found to be similar to the fishery-independent abundance index derived from the MEDITS programme.

  8. [Large vessel vasculitides].

    Science.gov (United States)

    Morović-Vergles, Jadranka; Puksić, Silva; Gracanin, Ana Gudelj

    2013-01-01

    Large vessel vasculitis includes Giant cell arteritis and Takayasu arteritis. Giant cell arteritis is the most common form of vasculitis affect patients aged 50 years or over. The diagnosis should be considered in older patients who present with new onset of headache, visual disturbance, polymyalgia rheumatica and/or fever unknown cause. Glucocorticoides remain the cornerstone of therapy. Takayasu arteritis is a chronic panarteritis of the aorta ant its major branches presenting commonly in young ages. Although all large arteries can be affected, the aorta, subclavian and carotid arteries are most commonly involved. The most common symptoms included upper extremity claudication, hypertension, pain over the carotid arteries (carotidynia), dizziness and visual disturbances. Early diagnosis and treatment has improved the outcome in patients with TA.

  9. Vessel segmentation in screening mammograms

    Science.gov (United States)

    Mordang, J. J.; Karssemeijer, N.

    2015-03-01

    Blood vessels are a major cause of false positives in computer aided detection systems for the detection of breast cancer. Therefore, the purpose of this study is to construct a framework for the segmentation of blood vessels in screening mammograms. The proposed framework is based on supervised learning using a cascade classifier. This cascade classifier consists of several stages where in each stage a GentleBoost classifier is trained on Haar-like features. A total of 30 cases were included in this study. In each image, vessel pixels were annotated by selecting pixels on the centerline of the vessel, control samples were taken by annotating a region without any visible vascular structures. This resulted in a total of 31,000 pixels marked as vascular and over 4 million control pixels. After training, the classifier assigns a vesselness likelihood to the pixels. The proposed framework was compared to three other vessel enhancing methods, i) a vesselness filter, ii) a gaussian derivative filter, and iii) a tubeness filter. The methods were compared in terms of area under the receiver operating characteristics curves, the Az values. The Az value of the cascade approach is 0:85. This is superior to the vesselness, Gaussian, and tubeness methods, with Az values of 0:77, 0:81, and 0:78, respectively. From these results, it can be concluded that our proposed framework is a promising method for the detection of vessels in screening mammograms.

  10. Americium behaviour in plastic vessels

    Energy Technology Data Exchange (ETDEWEB)

    Legarda, F.; Herranz, M. [Departamento de Ingenieria Nuclear y Mecanica de Fluidos, Escuela Tecnica Superior de Ingenieria de Bilbao, Universidad del Pais Vasco (UPV/EHU), Alameda de Urquijo s/n, 48013 Bilbao (Spain); Idoeta, R., E-mail: raquel.idoeta@ehu.e [Departamento de Ingenieria Nuclear y Mecanica de Fluidos, Escuela Tecnica Superior de Ingenieria de Bilbao, Universidad del Pais Vasco (UPV/EHU), Alameda de Urquijo s/n, 48013 Bilbao (Spain); Abelairas, A. [Departamento de Ingenieria Nuclear y Mecanica de Fluidos, Escuela Tecnica Superior de Ingenieria de Bilbao, Universidad del Pais Vasco (UPV/EHU), Alameda de Urquijo s/n, 48013 Bilbao (Spain)

    2010-07-15

    The adsorption of {sup 241}Am dissolved in water in different plastic storage vessels was determined. Three different plastics were investigated with natural and distilled waters and the retention of {sup 241}Am by these plastics was studied. The same was done by varying vessel agitation time, vessel agitation speed, surface/volume ratio of water in the vessels and water pH. Adsorptions were measured to be between 0% and 70%. The adsorption of {sup 241}Am is minimized with no water agitation, with PET or PVC plastics, and by water acidification.

  11. 78 FR 7371 - Fisheries Off West Coast States; Pacific Coast Groundfish Fishery; Trawl Rationalization Program...

    Science.gov (United States)

    2013-02-01

    ... enforcement activities were eligible to be recovered. The Council formed a Cost Recovery Committee (CRC... using Appendix B of the CRC Report from the September 2011 Council meeting (Agenda Item G.6.b) as..., identifier (state buyer code or USCG vessel documentation number), dates, weight of groundfish, ex-vessel...

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

    Science.gov (United States)

    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.

  13. Use of selective devices in trawls to support recovery of the Kattegat cod stock: a review of experiments and experience

    DEFF Research Database (Denmark)

    Madsen, Niels; Valentinsson, Daniel

    2010-01-01

    The spawning-stock biomass of cod (Gadus morhua) in the Kattegat area is at a historically low level. Throughout the past decade considerable efforts have been devoted to research on improving both species and size selectivity of the trawls used in the mixed demersal fishery in the area, because...... the bycatch. We review the results of previous and continuing experiments with various codend mesh sizes, mesh configurations, escape windows, sorting grids, sorting frames, and separator panels, but also changes in whole-trawl designs. Based on our review, we compare and discuss the gear-related technical...... measures and their effectiveness in maintaining a commercial fishery on viable stocks, yet protecting cod. We discuss the results in relation to changes in legislation and experience with implementation of new selective devices in recent years. We also discuss ways to create stronger incentives for fishers...

  14. Improving the size- and species selectivity of cod (Gadus morhua) in demersal mixed-species trawl fisheries

    DEFF Research Database (Denmark)

    Krag, Ludvig Ahm

    have been published in scientific journals and Paper 3 has been submitted to Fisheries Research. This review will take a broader perspective and will examine the capturing process, which is the basis for the selection process. Moreover, it discusses the existing methods and knowledge in the fields......For the last decade, the Kattegat-Skagerrak and the North Sea cod stocks have been at a critically low level. Several management initiatives were introduced to protect and aid the recovery of these cod stocks. Most fisheries in these areas are conducted in a multispecies setting, where several...... different species, including cod, are caught together. Demersal trawling is the predominant fishing method in Denmark, as measured by both catch value and volume. Demersal trawls also account for the highest discard rates of juvenile fish, including cod. The focus of this work was on improving...

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

    Directory of Open Access Journals (Sweden)

    Sven Sebastian Uhlmann

    Full Text Available 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.

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

    Directory of Open Access Journals (Sweden)

    Andrew J Penney

    Full Text Available 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.

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

    Science.gov (United States)

    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 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.

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

    Science.gov (United States)

    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.

  19. 50 CFR 648.8 - Vessel identification.

    Science.gov (United States)

    2010-10-01

    ... 50 Wildlife and Fisheries 8 2010-10-01 2010-10-01 false Vessel identification. 648.8 Section 648.8... identification. (a) Vessel name and official number. Each fishing vessel subject to this part and over 25 ft (7.6... or ocean quahog vessels licensed under New Jersey law may use the appropriate vessel identification...

  20. 2D Fast Vessel Visualization Using a Vessel Wall Mask Guiding Fine Vessel Detection

    Directory of Open Access Journals (Sweden)

    Sotirios Raptis

    2010-01-01

    and then try to approach the ridges and branches of the vasculature's using fine detection. Fine vessel screening looks into local structural inconsistencies in vessels properties, into noise, or into not expected intensity variations observed inside pre-known vessel-body areas. The vessels are first modelled sufficiently but not precisely by their walls with a tubular model-structure that is the result of an initial segmentation. This provides a chart of likely Vessel Wall Pixels (VWPs yielding a form of a likelihood vessel map mainly based on gradient filter's intensity and spatial arrangement parameters (e.g., linear consistency. Specific vessel parameters (centerline, width, location, fall-away rate, main orientation are post-computed by convolving the image with a set of pre-tuned spatial filters called Matched Filters (MFs. These are easily computed as Gaussian-like 2D forms that use a limited range sub-optimal parameters adjusted to the dominant vessel characteristics obtained by Spatial Grey Level Difference statistics limiting the range of search into vessel widths of 16, 32, and 64 pixels. Sparse pixels are effectively eliminated by applying a limited range Hough Transform (HT or region growing. Major benefits are limiting the range of parameters, reducing the search-space for post-convolution to only masked regions, representing almost 2% of the 2D volume, good speed versus accuracy/time trade-off. Results show the potentials of our approach in terms of time for detection ROC analysis and accuracy of vessel pixel (VP detection.

  1. All Autonomous Surface Vessel IRIS Shotpoint Navigation for Chirp Seismic Data in Apalachicola Bay collected on U.S. Geological Survey Cruise 06001 (ALLASV_NODUPES_SORT.SHP, Geographic, WGS84)

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — Apalachicola Bay and St. George Sound contain the largest oyster fishery in Florida, and the growth and distribution of the numerous oyster reefs here are the...

  2. Point Shapefile of 1000 Interval Seismic Shotpoint Navigation for Autonomous Surface Vessel IRIS Chirp Seismic Data in Apalachicola Bay Collected on U.S. Geological Survey Cruise 06001 (ASV_1000SHOT_SORT.SHP, Geographic, WGS84)

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — Apalachicola Bay and St. George Sound contain the largest oyster fishery in Florida, and the growth and distribution of the numerous oyster reefs here are the...

  3. Polyline-M Shapefile of Navigation Tracklines for Autonomous Surface Vessel IRIS Chirp Seismic Data in Apalachicola Bay collected on U.S. Geological Survey Cruise 06001 (ASV_LINES_CALIBRATED.SHP, Geographic, WGS84)

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — Apalachicola Bay and St. George Sound contain the largest oyster fishery in Florida, and the growth and distribution of the numerous oyster reefs here are the...

  4. BY FRUSTUM CONFINING VESSEL

    Directory of Open Access Journals (Sweden)

    Javad Khazaei

    2016-09-01

    Full Text Available Helical piles are environmentally friendly and economical deep foundations that, due to environmental considerations, are excellent additions to a variety of deep foundation alternatives available to the practitioner. Helical piles performance depends on soil properties, the pile geometry and soil-pile interaction. Helical piles can be a proper alternative in sensitive environmental sites if their bearing capacity is sufficient to support applied loads. The failure capacity of helical piles in this study was measured via an experimental research program that was carried out by Frustum Confining Vessel (FCV. FCV is a frustum chamber by approximately linear increase in vertical and lateral stresses along depth from top to bottom. Due to special geometry and applied bottom pressure, this apparatus is a proper choice to test small model piles which can simulate field stress conditions. Small scale helical piles are made with either single helix or more helixes and installed in fine grained sand with three various densities. Axial loading tests including compression and tension tests were performed to achieve pile ultimate capacity. The results indicate the helical piles behavior depends essentially on pile geometric characteristics, i.e. helix configuration and soil properties. According to the achievements, axial uplift capacity of helical model piles is about equal to usual steel model piles that have the helixes diameter. Helical pile compression bearing capacity is too sufficient to act as a medium pile, thus it can be substituted other piles in special geoenvironmental conditions. The bearing capacity also depends on spacing ratio, S/D, and helixes diameter.

  5. 2013 East Coast Vessel Tracklines

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Automatic Identification Systems (AIS) are a navigation safety device that transmits and monitors the location and characteristics of many vessels in U.S. and...

  6. SC/OQ Vessel Database

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Data tables holding information for the Surf Clam/Ocean Quahog vessel and dealer/processor logbooks (negative and positive), as well as individual tag information...

  7. 2011 Great Lakes Vessel Tracklines

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Automatic Identification Systems (AIS) are a navigation safety device that transmits and monitors the location and characteristics of many vessels in U.S. and...

  8. 2011 West Coast Vessel Tracklines

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Automatic Identification Systems (AIS) are a navigation safety device that transmits and monitors the location and characteristics of many vessels in U.S. and...

  9. 2013 Great Lakes Vessel Tracklines

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Automatic Identification Systems (AIS) are a navigation safety device that transmits and monitors the location and characteristics of many vessels in U.S. and...

  10. 2011 East Coast Vessel Tracklines

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Automatic Identification Systems (AIS) are a navigation safety device that transmits and monitors the location and characteristics of many vessels in U.S. and...

  11. Integrin binding: Sticking around vessels

    Science.gov (United States)

    Blatchley, Michael R.; Gerecht, Sharon

    2017-09-01

    A study demonstrates that controlled integrin binding on a biomaterial was capable of promoting vascular cell sprouting and formation of a non-leaky blood vessel network in a healthy and diseased state.

  12. Transposition of the great vessels

    Science.gov (United States)

    ... vessel called the ductus arteriosus open, allowing some mixing of the 2 blood circulations. A procedure using ... they are not already immune. Eating well, avoiding alcohol, and controlling diabetes both before and during pregnancy ...

  13. 2013 West Coast Vessel Tracklines

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Automatic Identification Systems (AIS) are a navigation safety device that transmits and monitors the location and characteristics of many vessels in U.S. and...

  14. Vessel Permit System Data Set

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — GARFO issues federal fishing permits annually to owners of fishing vessels who fish in the Greater Atlantic region, as required by federal regulation. These permits...

  15. 2011 Tug Towing Vessel Density

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Automatic Identification Systems (AIS) are a navigation safety device that transmits and monitors the location and characteristics of many vessels in U.S. and...

  16. 78 FR 40436 - Proposed Information Collection; Comment Request; Mandatory Shrimp Vessel and Gear...

    Science.gov (United States)

    2013-07-05

    ... Shrimp Vessel and Gear Characterization Survey AGENCY: National Oceanic and Atmospheric Administration... Shrimp Fishery Management Plan (FMP). The regulations for the Gulf Shrimp Vessel and Gear... Gear Characterization Form. The form will be provided by NMFS at the time of permit application and...

  17. Prosopomorphic vessels from Moesia Superior

    Directory of Open Access Journals (Sweden)

    Nikolić Snežana

    2008-01-01

    Full Text Available The prosopomorphic vessels from Moesia Superior had the form of beakers varying in outline but similar in size. They were wheel-thrown, mould-made or manufactured by using a combination of wheel-throwing and mould-made appliqués. Given that face vessels are considerably scarcer than other kinds of pottery, more than fifty finds from Moesia Superior make an enviable collection. In this and other provinces face vessels have been recovered from military camps, civilian settlements and necropolises, which suggests that they served more than one purpose. It is generally accepted that the faces-masks gave a protective role to the vessels, be it to protect the deceased or the family, their house and possessions. More than forty of all known finds from Moesia Superior come from Viminacium, a half of that number from necropolises. Although tangible evidence is lacking, there must have been several local workshops producing face vessels. The number and technological characteristics of the discovered vessels suggest that one of the workshops is likely to have been at Viminacium, an important pottery-making centre in the second and third centuries.

  18. Automated method for identification and artery-venous classification of vessel trees in retinal vessel networks.

    Directory of Open Access Journals (Sweden)

    Vinayak S Joshi

    Full Text Available The separation of the retinal vessel network into distinct arterial and venous vessel trees is of high interest. We propose an automated method for identification and separation of retinal vessel trees in a retinal color image by converting a vessel segmentation image into a vessel segment map and identifying the individual vessel trees by graph search. Orientation, width, and intensity of each vessel segment are utilized to find the optimal graph of vessel segments. The separated vessel trees are labeled as primary vessel or branches. We utilize the separated vessel trees for arterial-venous (AV classification, based on the color properties of the vessels in each tree graph. We applied our approach to a dataset of 50 fundus images from 50 subjects. The proposed method resulted in an accuracy of 91.44% correctly classified vessel pixels as either artery or vein. The accuracy of correctly classified major vessel segments was 96.42%.

  19. 76 FR 26705 - Proposed Information Collection; Comment Request; Commercial Fishing Vessel Cost and Earnings...

    Science.gov (United States)

    2011-05-09

    ...; Commercial Fishing Vessel Cost and Earnings Data Collection Survey in the Northeast Region AGENCY: National... hours and cost) of the proposed collection of information; (c) Ways to enhance the quality, utility, and...

  20. Effects of fishing power and competitive interactions among vessels on the effort allocation on the trip level of the Dutch beam trawl fleet

    NARCIS (Netherlands)

    Rijnsdorp, A.D.; Dol, W.; Hooyer, M.; Pastoors, M.A.

    2000-01-01

    Variations in catch rates in relation to the spatial distribution of beam trawlers were analyzed using mandatory logbook data from the Dutch fleet for 1990-1996. Catch rates by trip, corrected for differences in market value, showed a consistent seasonal pattern with the highest values found during