Journal articles: 'Trawl Shrimp Fishery'

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Larsen, Roger B., Bent Herrmann, Manu Sistiaga, Jesse Brinkhof, Ivan Tatone, and Lise Langård. "New approach for modelling size selectivity in shrimp trawl fisheries." ICES Journal of Marine Science 75, no. 1 (July 10, 2017): 351–60. http://dx.doi.org/10.1093/icesjms/fsx117.

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Abstract In the deep sea trawl fishery targeting shrimp (Pandalus borealis) and other cold-water shrimp species, fishers often use a Nordmöre sorting grid ahead of a small mesh codend to avoid bycatch. However, small fish can pass through the grid and are subsequently retained in the codend. This makes shrimp size selection complex and the size-dependent curve for both the shrimp and the bycatch species often exhibits a bell-shaped signature. In this study we developed a new model and method to estimate size selection in this fishery, conducted fishing trials in the Northeast Barents Sea, and applied the new method to quantify the individual and combined size selection of the Nordmöre grid and codend for deep water shrimp and two bycatch species. The size selectivity for both bycatch species showed the expected bell-shaped signature with low retention probability of very small and larger fish. The Nordmöre grid had high passage probability for all sizes, although it decreased slightly for the largest shrimps. The smallest shrimps were released by the codend.

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Ingólfsson, Ólafur Arnar, and Terje Jørgensen. "Shorter trawls improve size selection of northern shrimp." Canadian Journal of Fisheries and Aquatic Sciences 77, no. 1 (January 2020): 202–11. http://dx.doi.org/10.1139/cjfas-2018-0443.

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Discards of small northern shrimp (Pandalus borealis) are a problem in the Skagerrak northern shrimp trawl fishery. To reduce catches of small shrimp, we studied the effect of trawl belly length on size selectivity in November 2017 and June 2018 onboard 15 and 27 m double-rigged shrimp trawlers. The selectivity of the vessels’ standard trawl was compared with a trawl differing only in the belly length, being 37% shorter. The trawls had 40 mm bottom panels and cod ends of 35 mm mesh sizes. Eleven and 14 hauls were made, respectively, in 2017 aboard the 15 m vessel and in 2018 aboard the 27 m vessel. The trawls fished shrimp above 19 mm carapace length equally, while catch rates of shrimp below 15.5–16 mm carapace length in the shorter trawl were more than halved. The results were consistent between the two vessels. In short, modifying trawl length is a simple design modification that can reduce catches of small shrimp. Bycatch of Norway pout (Trisopterus esmarkii) was slightly reduced in the shorter trawl, unrelated to fish length.

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Watson, John, Daniel Foster, Scoll Nichols, Arvlnd Shah, Elizabeth Scoll-oenlon, and James Nanc. "The Development of Bycatch Reduction Technology in the Southeastern United States Shrimp Fishery." Marine Technology Society Journal 33, no. 2 (January 1, 1999): 51–56. http://dx.doi.org/10.4031/mtsj.33.2.8.

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Shrimp trawl bycatch is a significant source of fishery induced mortality for managed species including red snapper (Lutjanus campechanus Poey), Spanish mackerel (Scomberomorus maculatus MitcheU), and weakfish (Cynoscion regalis Baloch, Schneider) in the southeastern United States. These species have been overfished and are under both state and federal management plans which include regulations mandating reduction of shrimp trawl bycatch mortality. In 1990 the U.S. Congress passed amendments to the Magnuson Fishery Conservation and Management Act (16 U.S.C. 1854) which called for a research program that included the design and evaluation of approaches for reducing shrimp trawl bycatch mortality. A strategic planning initiative addressing finfish bycatch in the Gulf of Mexico and southeastern Atlantic shrimp fisheries was developed by the Gulf and South Atlantic Fisheries Foundation through funding and guidance provided by the National Marine Fisheries Service. A cooperative research plan was developed in 1992 which included the identification, development, and evaluation of gear options for reducing bycatch in the Gulf of Mexico and southeastern Atlantic shrimp fisheries. Between 1990 and 1996 one hundred and forty five bycatch reduction conceptual gear designs contributed by fishers, net shops, gear technicians, and biologists were evaluated. Sixteen of these designs were tested on cooperative commercial shrimp vessels by observers under the southeast regional cooperative bycatch program. Analyses of data from commercial vessel testing indicates that two bycatch reduction designs have potential to significantly reduce shrimp trawl bycatch for weakfish and Spanish mackerel in the southeastern Atlantic and two designs have the potential to significantly reduce red snapper bycatch in the Gulf of Mexico. The fisheye and the extended funnel bycatch reduction devices have been mandated for use in the southeastern Atlantic shrimp fishery and the fisheye and Jones/Davis bycatch reduction devices have been mandated for use in the Gulf of Mexico shrimp trawl fishery.

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Villalobos-Rojas, Fresia, Juan Carlos Azofeifa-Solano, Raquel Romero-Chaves, and Ingo S. Wehrtmann. "Hermit crabs associated to the shrimp bottom-trawl fishery along the Pacific coast of Costa Rica, Central America." Marine and Fishery Sciences (MAFIS) 33, no. 1 (June 18, 2020): 95–113. http://dx.doi.org/10.47193/mafis.3312020061806.

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Studies of the bycatch associated to the shrimp trawling fishery in the Pacific coast of Costa Rica do not assess small organisms (< 10 cm TL) and non-dominant species (< 0.1% of total catch). There is a void in assessing the maintenance of the ecology and ecosystem on which the fishery depends. Furthermore, the Constitutional Court of Costa Rica prohibited the renewal of existing and the issuing of new shrimp bottom-trawl licenses, indicating the necessity of more scientific information on the impacts of this fishery. We present the results of a 23-month study of the shrimp bottom-trawl fishery performed between 50 and 350 m deep in the Pacific coast of Costa Rica. A total of 109 hermit crabs were collected (six species and two families). Paguristes cf. holmesi was the most common species. Zone II presented the highest species richness and abundance. Most specimens (81.8 %) were caught in shallower waters (50-149 m). More than 45% of the trawls presented hermit crabs. It is imperative to further assess the trawling effects on non-commercial benthic fauna and changes on predator-prey relationships before issuing new shrimp licenses

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Lomeli, Mark J. M., Scott D. Groth, Matthew T. O. Blume, Bent Herrmann, and W. Waldo Wakefield. "Effects on the bycatch of eulachon and juvenile groundfish by altering the level of artificial illumination along an ocean shrimp trawl fishing line." ICES Journal of Marine Science 75, no. 6 (August 13, 2018): 2224–34. http://dx.doi.org/10.1093/icesjms/fsy105.

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Abstract We examined how catches of ocean shrimp (Pandalus jordani), eulachon (Thaleichthys pacificus), and juvenile groundfish could be affected by altering the level of artificial illumination along the fishing line of an ocean shrimp trawl. In the ocean shrimp trawl fishery, catches of eulachon are of special concern, as the species’ southern Distinct Population Segment is listed as “threatened” under the US Endangered Species Act. Using a double-rigged trawl vessel, with one trawl illuminated and the other unilluminated, we compared the catch efficiencies for ocean shrimp, eulachon, and juvenile groundfish between an unilluminated trawl and trawls illuminated with 5, 10, and 20 LED fishing lights along their fishing line. The addition of artificial illumination along the trawl fishing line significantly affected the average catch efficiency for eulachon, rockfish (Sebastes spp.), and flatfish, with the three LED configurations each catching significantly fewer individuals than the unilluminated trawl without impacting ocean shrimp catches. For Pacific hake (Merluccius productus), the ten LED-configured trawl caught significantly more fish than the unilluminated trawl. For the five and 20 LED configurations, mean Pacific hake catches did not differ from the unilluminated trawl. This study contributes new data on how artificial illumination can affect eulachon catches (and other fish) and contribute to their conservation.

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Greenman, Justin T., and Wayne E. Mcfee. "A characterisation of common bottlenose dolphin (Tursiops truncatus) interactions with the commercial shrimp trawl fishery of South Carolina, USA." J. Cetacean Res. Manage. 14, no. 1 (February 1, 2023): 69–79. http://dx.doi.org/10.47536/jcrm.v14i1.525.

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In the United States, interactions between the shrimp trawl fishery and bottlenose dolphins are known to exist; however, the level of mortality is largely unknown, and has not been studied in South Carolina, USA. The current study attempted to determine if interactions between bottlenose dolphins and the South Carolina commercial shrimp trawl fishery pose a significant threat to dolphin populations and if fishery related mortality is underreported. Onboard observations were made during a 25 day (August–December 2010) field study. No dolphin takes occurred during the observational period. These observations focused on direct physical interactions with the gear and depredation behaviours. Additionally, a subsample of the shrimp fishery in South Carolina was asked to participate in a mailed survey. The survey included questions related to gear, dolphin observations, and the status of the shrimp fishery. This paper also examines historical dolphin stranding data from the NOAA/CCEHBR MMIS database for signs of shrimp fishery interactions. A three-tiered flow diagram was developed to characterise each stranding case according to the likelihood that mortality resulted from trawler interaction. Field results point to significant dolphin presence around commercial trawlers (x2 = 23.406, p < 0.001). Survey results showed 12 unreported incidents of shrimp trawl fishery mortality of dolphins. Finally, stranding records revealed several more cases with signs of possible trawler interaction. The current US National Marine Fisheries Service (NOAA) designation of the fishery as a Category II fishery is correct. Increased observer coverage and improved communication with the fishery on the importance of reporting takes is warranted.

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Lomeli, Mark J. M., Scott D. Groth, Matthew T. O. Blume, Bent Herrmann, and W. Waldo Wakefield. "The efficacy of illumination to reduce bycatch of eulachon and groundfishes before trawl capture in the eastern North Pacific ocean shrimp fishery." Canadian Journal of Fisheries and Aquatic Sciences 77, no. 1 (January 2020): 44–54. http://dx.doi.org/10.1139/cjfas-2018-0497.

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This study examined the extent that eulachon (Thaleichthys pacificus) and groundfishes escape trawl entrainment in response to artificial illumination along an ocean shrimp (Pandalus jordani) trawl fishing line. Using a double-rigged trawler, we compared the catch efficiencies for ocean shrimp, eulachon, and groundfishes between an unilluminated trawl and a trawl illuminated with five green LEDs along its fishing line. Results showed a significant reduction in the bycatch of eulachon and yellowtail rockfish (Sebastes flavidus) in the presence of illumination. As eulachon are a species listed in the Endangered Species Act, this finding provides valuable information for fishery managers implementing recovery plans and evaluating potential fishery impacts on their recovery and conservation. For other rockfishes (Sebastes spp.) and flatfishes, however, we did not see the same effect as the illuminated trawl caught similarly or significantly more fishes than did the unilluminated trawl. Prior to this research, the extent that eulachon and groundfishes escape trawl capture in response to illumination along an ocean shrimp trawl fishing line was unclear. Our study has provided results to fill that data gap.

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Peixoto, Ualerson I., Adauto S. Mello-Filho, Bianca Bentes, and Victoria J. Isaac. "Trawl Fishing Fleet Operations Used to Illustrate the Life Cycle of the Southern Brown Shrimp: Insights to Management and Sustainable Fisheries." Fishes 7, no. 3 (June 17, 2022): 141. http://dx.doi.org/10.3390/fishes7030141.

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The purpose of this study was to better understand the life cycle of brown shrimp along the Amazon Continental Shelf by using spatial and temporal trawl fleet activities. A total of 208,121 specimens and 1281 trawls were studied throughout the course of 13 years of shrimp size composition. To investigate differences in length composition between fishing grounds, months, and depth, a PERMANOVA analysis was employed. A geographic information system was developed for environmental characterisation and spatiotemporal trawl fleet distribution. Our findings show that the industrial trawl shrimp fleet has a close relationship with shrimp biological characteristics, following shrimp migration patterns in different months, locations, and depths during different stages of their life cycle, and that this fleet acts on two-yearly cohorts. The management measures of limiting effort (number of vessels) appear enough to avoid overcapitalisation, but the closed period and a proposed no-take fishing zone appear insufficient for what was originally proposed. Ecosystem-based management strategies should be addressed immediately because they would be far more effective than traditional fishery-based management measures in promoting sustainable fishing.

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Larsen, Roger B., Bent Herrmann, Manu Sistiaga, Jesse Brinkhof, Kristine Cerbule, Eduardo Grimaldo, and Mark J. M. Lomeli. "Effect of the Nordmøre grid bar spacing on size selectivity, catch efficiency and bycatch of the Barents Sea Northern shrimp fishery." PLOS ONE 17, no. 12 (December 27, 2022): e0277788. http://dx.doi.org/10.1371/journal.pone.0277788.

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The introduction of the Nordmøre grid in shrimp trawls has reduced the bycatch of non-target species. In the Norwegian Northern shrimp (Pandalus borealis) fishery, the mandatory selective gear consists of a Nordmøre grid with 19 mm bar spacing combined with a 35 mm mesh size diamond mesh codend. However, fish bycatch in shrimp trawls remains a challenge and further modifications of the gear that can improve selectivity are still sought. Therefore, this study estimated and compared the size selectivity of Nordmøre grids with bar spacings of 17 and 21 mm. Further, the effect of applying these two grids on trawl size selectivity was predicted and compared to the legislated gear configuration. Experimental fishing trials were conducted in the Barents Sea where the bottom trawl fleet targets Northern shrimp. Results were obtained for the target species and two by-catch species: cod (Gadus morhua) and American plaice (Hippoglossoides platessoides). This study demonstrated that reducing bar spacing can significantly reduce fish bycatch while only marginally affecting catch efficiency of Northern shrimp. This is a potentially important finding from a management perspective that could be applicable to other shrimp fisheries where flexibility in the use of different grid bar spacings may be beneficial to maximize the reduction of unwanted bycatch while minimizing the loss of target species.

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Mizyurkin, Michael A., Valery N. Koblikov, Oleg N. Kruchinin, and Ilia A. Korneychuk. "Some aspects of pot fishery on humpback shrimp Pandalus hypsinotus and its biological condition in the southern part of the subzone Primorye (Japan Sea) in autumn 2013." Izvestiya TINRO 178, no. 3 (September 30, 2014): 234–45. http://dx.doi.org/10.26428/1606-9919-2014-178-234-245.

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Data on productivity of pot fishery on humpback shrimp at the coast of Primorye are presented, actual in conditions of its trawl fishery ban in the northwestern Japan Sea. Biological parameters of the shrimp in the fishing season are considered, and dynamics of the catches is analyzed for one of the major fishing grounds. Species composition and abundance of by-catch in the shrimp pots are discussed. Dependence of the shrimp catch on options of the bite preparation is determined.

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He, Pingguo, and Vincent Balzano. "Reducing the catch of small shrimps in the Gulf of Maine pink shrimp fishery with a size-sorting grid device." ICES Journal of Marine Science 64, no. 8 (July 26, 2007): 1551–57. http://dx.doi.org/10.1093/icesjms/fsm098.

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Abstract He, P., and Balzano, V. 2007. Reducing the catch of small shrimps in the Gulf of Maine pink shrimp fishery with a size-sorting grid device. – ICES Journal of Marine Science, 64: 1551–1557. Since implementation of the Nordmøre grid in the Gulf of Maine pink shrimp (Pandalus borealis) trawl fishery in the early 1990s, fish bycatch has been reduced drastically. However, the Nordmøre grid does not reduce the amount of small shrimps landed when the shrimps are on the fishing grounds. This paper reports on two designs of a new size-sorting grid system, one with a funnel and one without. The designs' main feature is the size-sorting grid's position, installed in front of the main Nordmøre grid. They were tested in the flume tank and at sea. Parallel tows involving two vessels and alternating tows using one vessel were made to compare the size-sorting grid system. Both size-sorting designs reduced the number of small shrimps in the catch significantly, by 38 and 45 kg−1 of catch, respectively. There was some reduction in shrimp catch rates, presumably from the release of small shrimps. There were no significant differences in the number or quantity of major bycatch species for the commercial grid and the two experimental grid designs. The designs were practical to operate and easy to install. Their application could reduce the catch of small shrimps in the pink shrimp fishery in the Gulf of Maine and in other areas.

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Eayrs, Steve, Nguyen Phong Hai, and Janet Ley. "Assessment of a juvenile and trash excluder device in a Vietnamese shrimp trawl fishery." ICES Journal of Marine Science 64, no. 8 (October 8, 2007): 1598–602. http://dx.doi.org/10.1093/icesjms/fsm123.

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Abstract Eayrs, S., Hai, N. P., and Ley, J. 2007. Assessment of a juvenile and trash excluder device in a Vietnamese shrimp trawl fishery. – ICES Journal of Marine Science, 64: 1598–1602. In this study, we (i) identified why Vietnamese shrimp fishers land juvenile fish illegally; (ii) identified groups of fishers that would use a bycatch reduction device (BRD) to exclude these fish; (iii) studied the hydrodynamic performance of a juvenile and trash excluder device (JTED) in a flume tank; and (iv) assessed the performance of this device under commercial fishing conditions. Based on the responses of 65 fishers to a questionnaire, we found that juvenile fish are now an important economic component of the total catch, and that fishers operating larger boats were more willing to use a JTED to exclude these fish than fishers operating smaller boats. The hydrodynamic study of a JTED identified the location of low-velocity regions around the device and codend, and this information can be used to identify the location of a secondary BRD to allow more fish to escape. The at-sea assessment of this device found that 73% of juvenile fish, 16% of valuable fish, and 8% of shrimp were excluded by the JTED, although most valuable fish and shrimp were smaller than the minimum legal landing size. Overall, this loss represents a 9% reduction in revenue. Yield-per-recruit analysis indicated that this could be offset by not catching fish less than the minimum legal landing size.

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Yang, Bingzhong, and Bent Herrmann. "T90 Codends Improve the Size Selectivity and Catch Efficiency of Shrimp Trawl Fisheries for Southern Velvet Shrimp (Metapenaeopsis palmensis) in the South China Sea." Sustainability 14, no. 19 (September 26, 2022): 12208. http://dx.doi.org/10.3390/su141912208.

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In order to obtain gear-based management instruments of shrimp trawl fishery for southern velvet shrimp in the South China Sea (SCS), the size selectivity and catch efficiency of four codends were tested and compared. These codends included two mesh sizes, 30 and 35 mm, and two mesh shapes, T0 (diamond-mesh) and T90 (diamond-mesh turned by 90°), respectively. Our results demonstrated that increasing the mesh-sizes of the T0 codends or/and applying the T90 codends would statistically and significantly improve the size selectivity and catch efficiency. Comparing the size selectivity and catch efficiency of four codends tested, and accounting for the results of the previous study, we conclude that the T0 codend with a mesh size of 35 mm (T0_35) or T90 codend with a mesh size of 30 mm (T90_30) would be potential choices for mitigating the bycatch issue of undersized individuals for southern velvet shrimp (Metapenaeopsis palmensis) in the SCS. We recommend that they are applied as the compulsory gears in the fishery management regulation. Our study will be beneficial for the decision-making regarding gear-based management for sustainable fishing in the specific shrimp trawl fishery of the SCS.

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Mendo, Jaime, Tania Mendo, Patricia Gil-Kodaka, Jimmy Martina, Iván Gómez, Ruggeri Delgado, Jhenifer Fernández, et al. "Bycatch and discards in the artisanal shrimp trawl fishery in Northern Peru." PLOS ONE 17, no. 6 (June 22, 2022): e0268128. http://dx.doi.org/10.1371/journal.pone.0268128.

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This study analyses the bycatch composition of an artisanal shrimp trawl fleet operating between Cabo Blanco and Máncora in Northern Peru between April 2019 and March 2020. A total of 300 hauls were analysed with respect to target catch and bycatch (consisting of other commercial species, discards, and macroalgae). A total of 277 species were recorded including 111 species of fish, 65 species of molluscs, 51 species of crustaceans, 22 species of algae, 12 species of cnidarian, 9 species of echinoderms, 4 species of Bryozoa and 3 species of polychaeta. Capture per unit effort (CPUE, kg.h-1) was highest for fish, followed by crustaceans, algae and molluscs. The target species Penaeus californiensis coffee shrimp constituted 17.8% of the overall catch,82.2% represented bycatch, and 50.6% represented discards. Coffee shrimps were more abundant in June and November 2019 and in January and February 2020. Highest bycatch CPUE occurred in May, June and December 2019. The most abundant species in the bycatch throughout the study period were sand perch (Diplectrum conceptione, 16% weight of the total catch), the macroalgae caulerpa (Caulerpa filiformis, 13%), sole flounder (Etropus ectenes, 6.4%), Pacific drum (Larimus pacificus, 5.7%), and lumptail searobin (Prionotus stephanophrys, 5.1%). Overall, the contribution of sand perch and flounder, exceeded the weight of coffee shrimp, therefore the interpretation that shrimp is the sole target species needs to be revised. The number of discarded species per month increased towards the spring months with the highest value in November. This study represents the first characterisation of bycatch in the artisanal trawling fishery in the Piura region in northern Peru and reveals a high proportion of bycatch in the fishery but also hints at potential temporal management measures that could be imposed to reduce the levels of bycatch. For example, the months of May and December had the greatest bycatch to shrimp ratios and the fishery could potentially be closed to avoid high bycatch risk, however, longer term information is needed to assess if the trends observed in bycatch are similar over longer periods of time. The species characterisation of bycatch also provides information for the design of modified nets which would target the reduction of small fish present in the catch.

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Taiwo, I. O., and O. A. Olopade. "Size Composition of Fish By-Catch Species from Industrial Shrimp Trawl Fishery in Nigerian Coastal Waters." ILMU KELAUTAN: Indonesian Journal of Marine Sciences 22, no. 4 (December 13, 2017): 169. http://dx.doi.org/10.14710/ik.ijms.22.4.169-173.

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Fish species composition of by-catch in the industrial shrimp trawl fishery in Nigeria was investigated with the Sciaenidae family being the most prevalent by-catch fish species. In order of prevalence Pseudolithus elongatus with a mean weight and length of 15.28g and 86.39mm, respectively and Pseudolithus typus (n= 102) having an average weight of 18.76g and mean length of 88.01mm. Other fish by-catch species include Pseudolithus senegalensis (n= 99, mean weigh = 15.49g, mean length= 88.60mm); Galeoides decadactylus (n= 59, mean weight= 15.26g, mean length= 87.66mm); Pteroscion peli (n= 48, mean weight= 16.05g, mean length = 88.23mm); Drepane africana (n= 33, mean weight= 13.29g, mean length= 45.73mm) and Cynoglossus senegalensis (n= 11, mean weight= 21.78g, mean length = 86.45mm). Despite the small number of Cynoglossus senegalensis, it had the highest weight contribution to the by-catch. Significant (P<0.01) relationship exists between weight and length of fish species. The adjusted R2 of the parameters indicated that 19.4% of the weight gained is accounted for by increase in length of Pseudolithus elongatus; 1.7% in Pseudolithus typus; 31.7% in Pseudolithus senegalensis; 13.7% in Galeoides decadactylus; 7.8% in Pteroscion peli; 57.4% in Drepane Africana; and 48.9% in Cynoglossus senegalensis. The by-catch associated with shrimp trawls should be properly monitored and controlled to reduce the quantity of non-target fish species in their catch. Also, the use of diamond-shaped 44mm mesh size for shrimp should be encouraged or made mandatory for fishers to reduce fish by-catch. Keywords: Shrimp, by-catch, fishery, weight

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Foster, S. J., and A. C. J. Vincent. "Tropical shrimp trawl fisheries: Fishers’ knowledge of and attitudes about a doomed fishery." Marine Policy 34, no. 3 (May 2010): 437–46. http://dx.doi.org/10.1016/j.marpol.2009.09.010.

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Yang, Bingzhong, Bent Herrmann, and Rong Wan. "Improving the size selectivity and exploitation pattern of cocktail shrimp (Trachypenaeus curvirostris) in shrimp trawl fishery of the South China Sea." PLOS ONE 18, no. 12 (December 13, 2023): e0295776. http://dx.doi.org/10.1371/journal.pone.0295776.

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In order to improve the size selectivity and exploitation pattern for cocktail shrimp (Trachypenaeus curvirostris) in shrimp trawl fishery of the South China Sea (SCS), selective properties of four codends were tested and compared. These experimental codends involved two mesh sizes, 30 and 35 mm, and two mesh shapes, diamond-mesh (T0) and diamond-mesh turned by 90 degree (T90), respectively. Our results demonstrated that increasing the mesh sizes in T0 codends or/and applying T90 codends would improve the selective properties for cocktail shrimp in the SCS. By comparing selectivity parameters, delta selectivity and exploitation pattern indicators, the T90 codend with 35-mm mesh size (T90_35) presented the best selective properties for cocktail shrimp in the studied areas. It will be a potential choice to substitute the currently legal codend in fisheries management to mitigate the bycatch of undersized cocktail shrimp in shrimp trawl fisheries of the SCS.

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Engaas, Arill, Daniel Foster, Bret Dominy Hataway, John W. Watson, and Ian Workman. "The Behavioral Response of Juvenile Red Snapper (Lutjanus campechanus) to Shrimp Trawls that Utilize Water Flow Modifications to Induce Escapement." Marine Technology Society Journal 33, no. 2 (January 1, 1999): 43–50. http://dx.doi.org/10.4031/mtsj.33.2.7.

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Clear differences in swimming ability between finfish and shrimp in trawls have been utilized in the Southeastern U.S shrimp fishery to reduce the by catch of finfish. The Jones/Davis device which has been mandated for use in the Gulf of Mexico shrimp fishery uses four windows to provide an escape path for fish while a funnel keeps the shrimp away from the windows, reduces water flow around the windows, and acts as a leading panel to guide the fish out of the trawl. Observations of fish behavior showed that finfish generally reacted to the slack water flow created by the funnel by swimming towards the lowest water flow area. The escape rate of finfish such as juvenile red snapper (Lutjanus campechanus), however, was low and random during towing when no net surging and fish crowding occurred. The highest escape rates occurred during slow down prior to haulback, but were dependent on the haul back procedure. This may help explain the haul-to-haul variation in escapement documented for the Jones/Davis device. Modifications and techniques to improve escape rates during towing are discussed.

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He, Pingguo, Christopher Rillahan, and Vincent Balzano. "Reduced herding of flounders by floating bridles: application in Gulf of Maine Northern shrimp trawls to reduce bycatch." ICES Journal of Marine Science 72, no. 5 (December 23, 2014): 1514–24. http://dx.doi.org/10.1093/icesjms/fsu235.

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Abstract We hypothesized that a floating trawl bridle that does not contact the seabed would reduce the herding of fish, especially bottom dwelling flounders, and thus reduce bycatch of these fish in shrimp trawls. We further hypothesized that, due to the non-herding nature of northern shrimp (Pandalus borealis), the use of an off-bottom floating bridle would not reduce shrimp catch. These hypotheses were tested in the field by comparing a trawl with regular bottom-tendering wire bridles and the same trawl with floating synthetic bridles in the Gulf of Maine northern shrimp fishery. As expected, no statistically significant differences in catch rates and size were found for the targeted northern shrimp (146.3 ± 10.58 kg h−1 control vs. 140.8 ± 9.35 kg h−1, p = 0.13). Total finfish bycatch was reduced by 14.9%, and the difference was statistically different (p = 0.01). The most important reduction was the catch of juvenile American plaice (Hippoglossoides platessoides) with a significant reduction of 20.0% (p = 0.01). For witch flounder (Glyptocephalus cynoglossus), a reduction of 19.3% was found, but it was not statistically significant (p = 0.14). The reduction of Acadian redfish (Sebastes fasciatus) (by 28.0%, p = 0.02) was also statistically different. Catch of targeted silver hake (Merluccius bilinearis) was reduced by 10.8%, but the difference was only marginally significant (p = 0.07). An analysis of length frequencies for the targeted shrimp and major bycatch species revealed no size-related selection between the gears with regular bridles and floating bridles. The reductions in flounder bycatch indicate reduced herding of benthic species when the bridles are kept off bottom. This easy modification may be readily adopted in the northern shrimp fisheries in the North Atlantic, and can also possibly be applied in other shrimp and prawn fisheries with further experimentation.

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Fatema, Umme Kaniz, Hasan Faruque, Md Abdus Salam, and Hiroyuki Matsuda. "Vulnerability Assessment of Target Shrimps and Bycatch Species from Industrial Shrimp Trawl Fishery in the Bay of Bengal, Bangladesh." Sustainability 14, no. 3 (February 1, 2022): 1691. http://dx.doi.org/10.3390/su14031691.

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Productivity susceptibility analysis (PSA) is a semi-quantitative ecological risk assessment tool, widely used to determine the relative vulnerability of target and non-target species to fishing impacts. Considering the available information on species-specific life-history and fishery-specific attributes, we used PSA to assess the relative risk of the 60 species interacting with the shrimp trawl fishery in the Bay of Bengal, Bangladesh. Penaeus monodon, the most important target, and Metapenaeus monoceros, the highest catch contributor, along with other 15 species were in the moderate-risk category, while seven non-target bycatch species were in the high-risk category. PSA-derived vulnerability results were validated with IUCN extinction risk, exploitation rate and stocks’ catch trend. The majority of the identified species showed high productivity (37%) and high susceptibility (46%), and all the moderately and highly vulnerable species were subjected to overfishing conditions by shrimp trawl fishery, which coincided with the vulnerability scores (V ≥ 1.8). Species with V ≥ 1.8 mostly showed a decreasing catch trend, while the species with a stable or increasing catch trend had a V ≤ 1.72. Data quality analysis of productivity and susceptibility attributes indicated that the majority of species were considered data-limited, which emphasizes the acquisition of data on spatio-temporal abundance, catch and effort, and biological information specifically relating to species age, growth, and reproduction. However, our findings can assist fishery administrators in implementing an ecosystem approach to ensure the sustainability and conservation of marine biodiversity in the Bay of Bengal.

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Peixoto, Ualerson Iran, Bianca Bentes, Humber Agrelli Andrade, and Victoria Judith Isaac. "Length-based assessment of southern brown shrimp stock from trawl fisheries on the Amazon Continental Shelf." Research, Society and Development 10, no. 8 (July 15, 2021): e44410817394. http://dx.doi.org/10.33448/rsd-v10i8.17394.

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Virtual Population Analysis (VPA) is a diagnostic tool that providing valuable input for management decisions to sustainable catches for marine fisheries. Industrial shrimp trawling produces one of the most valuable export commodities in the Brazilian fishery sector. Due to the profitability, there is pressure on government agencies to increase the number of fishing licenses. The present study used the body-length data available for the industrial southern brown shrimp trawling fleet of the Amazon Continental Shelf (ACS), Brazil, to estimate the current maximum sustainable yield and test the potential effects of increased effort on the sustainability of this fishery. The available data encompasses 13 years of onboard monitoring of shrimp trawling. The VPA was run in an Excel spreadsheet. The results indicate that the ACS shrimp stock has high fishing (F) mortality rates, although exploitation levels can be considered adequate below the MSY. An increase of up to 40% in fishery effort – including the expansion of the number of vessels – would not result in overfishing, although we would not recommend an increase in effort, as this may increase impacts on the bycatch fauna and eventual economic losses in the event of the failure of recruitment.

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Miotto, Maiara Larissa, Barbara Maichak de Carvalho, and Henry Louis Spach. "Does the closed fishing season influence the ichthyofauna consumed by Larus dominicanus?" Brazilian Journal of Oceanography 65, no. 1 (March 2017): 9–18. http://dx.doi.org/10.1590/s1679-87592017112206501.

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Abstract Fish that are incidentally caught by shrimp trawling represent a predictable and abundant resource for feeding several bird species, especially for the gull Larus dominicanus. This fishing activity is subject to disruptions throughout the year during closed fishing seasons, when other fishing modalities are exercised, which can alter the composition, abundance and size of the fish bycatch. This study evaluated the influence of the restriction of fishing period of shrimp (closed season) on the diet of L. dominicanus, on the Paraná State coast. From December 2013 to August 2014, 10 pellets were collected per month in two distinct areas that have shrimp trawl fishery as the main economic activity: one continental and another in an estuarine island. In total, 920 fish were identified, divided into four families and 15 species, especially the family Sciaenidae with 11 species. There were differences in abundance and biomass of species between areas and between seasons of pre-closure, closure and post-closure. Differences for the mean total length of the species were only detected between the pre-closed and closed seasons in one area. This study evidenced the strong relationship between L. dominicanus and the shrimp trawl fishery, the species composition identified in the pellets and their respective morphometric measurements follow the same pattern of the literature for fish discarded in trawling activities.

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Larsen, Roger B., Manu Sistiaga, Bent Herrmann, Jesse Brinkhof, Ivan Tatone, and Juan Santos. "The effect of Nordmøre grid length and angle on codend entry of bycatch fish species and shrimp catches." Canadian Journal of Fisheries and Aquatic Sciences 76, no. 2 (February 2019): 308–19. http://dx.doi.org/10.1139/cjfas-2018-0069.

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The Nordmøre grid is regarded as an efficient bycatch-reducing device and is used in various shrimp trawl fisheries globally. However, in some shrimp fisheries, bycatch remains a problem that seriously impacts commercial trawl activities. This study tested and compared the performance of two versions of the Nordmøre grid in the northeast Arctic deepwater (northern) shrimp (Pandalus borealis) fishery, a standard version with an operating angle of approximately 45° and a longer version of the grid (40% longer) with an operating angle of approximately 30°. The grid passage probability for the bycatch of juvenile cod (Gadus morhua), haddock (Melanogrammus aeglefinus), American plaice (Hippoglossoides platessoides), and redfish (Sebastes spp.) increased significantly for certain size ranges of fish when using the longer grid. The longer grid also resulted in a significant increase in grid passage probability for large shrimp. Previous studies have reported that a reduced operating angle can lead to a lower grid passage probability for bycatch fish species and shrimp; however, the results of the current study demonstrate that a longer Nordmøre grid more than compensates for the reduced operational angle.

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Pezzuto, Paulo Ricardo, José Angel Alvarez Perez, and Roberto Wahrlich. "Deep-sea shrimps (Decapoda: Aristeidae): new targets of the deep-water trawling fishery in Brazil." Brazilian Journal of Oceanography 54, no. 2-3 (September 2006): 123–34. http://dx.doi.org/10.1590/s1679-87592006000200003.

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Following the recent expansion of the Brazilian fishery to slope fishing grounds, a new directed trawl fishery for aristeid shrimps emerged since mid 2002. Aristaeopsis edwardsiana has been the main component of the catches attaining 88.4% of total shrimp production. Aristaeomorpha foliacea and Aristeus antillensis have composed significantly smaller fractions of the landings (9.8 % and 1.8 % respectively). Two main grounds were located in the southeastern region (ca. 19º - 25ºS) and one in the northern border of the Brazilian EEZ (ca. 4º30' - 5ºN). Catches have been extremely concentrated between the 700 and 750 m isobaths. Mean catch rates of A. edwardsiana oscillated between 6.5 and 9.7 kg.h-1. The other species have been caught at considerably lower rates (0.1 - 0.6 kg.h-1 and 0.1 - 1.3 kg.h-1, respectively). A seasonal pattern in A. edwardsiana catches is suggested, with maximum values obtained between July and December. While largely directed to the shrimps, incidental catches of the royal crab (Chaceon ramosae) attained, on average, 22 % of the total landings.

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Paula, Meriane dos Santos, Roberta Freitas, Rannyele Passos Ribeiro, Carlos Alberto de Moura Barboza, and Christine Ruta. "Bycatch of Asteroidea from shrimp trawl fishery in the southwestern Atlantic Ocean – Brazil." Papéis Avulsos de Zoologia 62 (February 8, 2022): e202262007. http://dx.doi.org/10.11606/1807-0205/2022.62.007.

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Shrimp trawling is considered a significant negative impact on the marine ecosystem, especially on the benthic community. Sea stars (Echinodermata: Asteroidea) are one of the most affected groups by unintentional catches. This study was performed at the Santana Archipelago, a Marine Protected Area in the northern region of Rio de Janeiro State, between 2008-2009. Sea stars accidentally caught by trawling were collected during open and closed season of the shrimp fisheries (Xiphopenaeus kroyeri) at depths of 5-60 m. A generalized linear zero-inflated model was applied to test for differences in capture between fishing seasons and depths. A total of 158 sea star specimens were captured. These specimens were identified as Asterina stellifera, Astropecten acutiradiatus, Astropecten brasiliensis, Astropecten cingulatus, Luidia alternata alternata, Luidia clathrata, Luidia ludwigi scotti, Luidia senegalensis. The sea stars A. brasiliensis and L. senegalensis are currently considered as vulnerable species in the Brazilian official list of threatened species. The higher capture of sea stars was shown in deepest areas, and there was no significant difference in the number of specimens between seasons. This is the first study about asteroids accidentally captured by shrimp trawling.

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Griffith, David, and Roger A. Rulifson. "Preliminary Characterization of the North Carolina Autumn Recreational Shrimp Trawl Fishery." North American Journal of Fisheries Management 17, no. 3 (August 1997): 696–702. http://dx.doi.org/10.1577/1548-8675(1997)017<0696:pcotnc>2.3.co;2.

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Al-Baz, A., and W. Chen. "An assessment of bycatch reduction devices in Kuwait's shrimp trawl fishery." Journal of Applied Ichthyology 31, no. 1 (December 5, 2014): 16–26. http://dx.doi.org/10.1111/jai.12653.

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Al-Mamry, J. M. "The bycatch composition of shrimp trawl fishery in the Oman coastal waters, the Arabian Sea." Acta Ichthyologica et Piscatoria 45, no. 3 (September 30, 2015): 273–83. http://dx.doi.org/10.3750/aip2015.45.3.06.

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Eichert, Moritz, Aida Campos, Paulo Fonseca, Victor Henriques, and Margarida Castro. "Preliminary results on the use of semi-floating shrimp traps for the striped soldier shrimp, Plesionika edwardsii (Crustacea: Decapoda: Pandalidae), off the Algarve coast (southern Portugal)." Scientia Marina 82, S1 (December 20, 2018): 209. http://dx.doi.org/10.3989/scimar.04758.02a.

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The present study provides an account of an experimental survey aiming at the evaluation of the catchability of the striped soldier shrimp, Plesionika edwardsii, using semi-floating shrimp traps off the Algarve coast (southern Portugal). Currently, this species is not targeted by the crustacean bottom trawl fleet, and preliminary results on product value suggest that this may become an economically viable new fishery. Preliminary results suggest that this fishery could contribute to the diversification of fixed gears of low environmental impact targeting deep-water crustaceans, in agreement with the objectives of both the Marine Strategy Framework Directive and the reformed Common Fisheries Policy. However, potential spatial conflicts with trawling, the unknown size of the resource and a necessary precautionary approach may limit the number of licences that can be granted.

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ARAÚJO, Paulo Victor do Nascimento, Alex Barbosa de MORAES, Flávia LUCENA FRÉDOU, and Fúlvio Aurélio de Morais FREIRE. "THE INFLUENCE OF THE COASTAL CURRENT ON THE ESTIMATION OF RELATIVE ABUNDANCE INDICES IN SMALL-SCALE SHRIMP FISHERY." Boletim do Instituto de Pesca 47 (2021): e665. http://dx.doi.org/10.20950/1678-2305/bip.2021.47.e665.

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The aim of this scientific note was to evaluate the influence of the coastal current on the estimation of relative abundance indices for small-scale marine shrimp trawling to indicate the best relative abundance index to be used for stock assessment and conservation. Georeferenced experimental trawls were carried out with standardized equipment and capture time on the coast of Rio Grande do Norte, northeastern Brazil. Drags followed convergent and divergent orientations in relation to the flow of the local coastal current. The results showed that the direction of the coastal current flow directly influences the distances and drag shifts, generating variations in the sampling effort and, consequently, bias when using Catch per Unit Effort (CPUE) as a relative abundance index. Conversely, the adoption of Catch per Unit of Swept Area (CPUA) as an index of relative abundance for shrimp trawling becomes more suitable since the variations in the distances of trawl shifts are perceptible through this index.

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Yang, Bingzhong, Bent Herrmann, Lei Yan, Jie Li, and Teng Wang. "Comparing size selectivity and exploitation pattern of diamond-mesh codends for Southern velvet shrimp (Metapenaeopsis palmensis) in shrimp trawl fishery of the South China Sea." PeerJ 9 (November 2, 2021): e12436. http://dx.doi.org/10.7717/peerj.12436.

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In this study, size selectivity and exploitation pattern of six diamond-mesh codends with different mesh sizes, ranging from 25 to 54 mm, for Southern velvet shrimp (Metapenaeopsis palmensis) were tested and compared in a shrimp trawl fishery of the South China Sea (SCS). We used a codend with a mesh size of 25 mm (D25) as a starting point, which is the minimum mesh size (MMS) currently regulated in the studied area. Four different fishing population scenarios were applied to quantify and compare how mesh sizes of codends used would impact the size selectivity and exploitation pattern for the target shrimp species. The results demonstrated that the D25 codend was not proper for protecting juvenile shrimp at the studied area. By applying this legal codend, L50 (50% retention length) of the target shrimp species was below its minimum conservation reference size (MCRS, 7.0 cm total length), the retention probability of shrimp with a length of MCRS was above 95% CI [91–99] and more than 43% of undersized shrimp was retained. To mitigate the bycatch issue of undersized shrimp, increasing the mesh size in the diamond mesh codend is a simple and effective option. However, the loss of catch efficiency for marketable shrimp is a major concern while increasing the mesh size. A good compromise between releasing undersized shrimp and maintaining the legal individuals is manifested by using the codend with 35 mm mesh size (D35). Our study will be beneficial for the management of shrimp trawl fisheries in the SCS.

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Coale, J. Stuart, Roger A. Rulifson, James D. Murray, and Robert Hines. "Comparisons of Shrimp Catch and Bycatch between a Skimmer Trawl and an Otter Trawl in the North Carolina Inshore Shrimp Fishery." North American Journal of Fisheries Management 14, no. 4 (November 1994): 751–68. http://dx.doi.org/10.1577/1548-8675(1994)014<0751:coscab>2.3.co;2.

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Ponce, Tania S., Luis A. Cubillos, Enzo Acuña, and Cecilia Gatica. "Diet of the Dusky finless skate Gurgesiella furvescens (Chondrichthyes: Rajidae) from the continental shelf and slope of the north-central area of Chile." Revista de Biología Marina y Oceanografía 57, Especial (October 4, 2022): press. http://dx.doi.org/10.22370/rbmo.2022.57.especial.3331.

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The dusky finless skate Gurgesiella furvescens appears sporadically as part of the bycatch in the trawl fishery targeting demersal crustaceans on the continental shelf and upper slope of the north-central area of Chile (26ºS-33ºS). Demersal crustaceans could be forage for deep-water predators such as G. furvescens, and sizes and shapes of prey eaten could be restricted by mouth size. The diet composition of G. furvescens was determined based on specimens collected from the bycatch of trawls targeting demersal crustaceans in 2013. Stomach contents revealed nylon shrimp Heterocarpus reedi (32.8% by weight), deep-water shrimp Haliporoides diomedeae (7.2% by weight), and indeterminate crustaceans (9.0% by weight). The diet composition was similar between sexes, body length, or depth strata. Prey size was a linear function of Gurgesiella furvescens mouth width, and prey mass positively related with G. furvescens individual mass. Although squat-lobsters Pleuroncodes monodon and Cervimunida johni were abundant in the study area, the nylon shrimp and deep-water shrimp in the diet of G. furvescens may be due to the preference or selection of this kind of prey in deep waters.

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Yuriev, D. N., V. S. Lukyanov, and A. Yu Povarov. "Distribution, fishery and some features of biology for Sclerocrangon salebrosa and Argis lar (Caridea, Crangonidae) in the northwestern Okhotsk Sea." Izvestiya TINRO 200, no. 3 (October 3, 2020): 551–70. http://dx.doi.org/10.26428/1606-9919-2020-200-551-570.

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Trawl fishery of shrimps Sclerocrangon salebrosa and Argis lar in the Sakhalin Bay of the Okhotsk Sea has started in 2014 and develops rapidly. Meanwhile, spatial distribution of these species is not known well and their biology and stock dynamics are not studied. State of the fishery and distribution patterns of S. salebrosa and A. lar in the northwestern Okhotsk Sea are investigated on the data collected by the authors aboaed commercial fishing vessels and in the accounting trawl survey conducted aboard RV Dmitry Peskov in summer of 2019, as well as some features of their biology are considered. In total, 542 commercial trawl catches collected in 2015–2019 with horizontal opening 36 m from the depth of 39–140 m and 147 trawl catches collected during the survey with horizontal opening 16 m from the depth of 11–321 m are analyzed; 21,590 shrimp specimens caught within the period from June 23 to November 2 are examined. During 2014–2019, the number of shrimp fishing vessels in the Sakhalin Bay has increased from 1 to 6, their annual landing — from 78.7 to 642.0 t (376 t of S. salebrosa and 266 t of A. lar in 2019). Their mean catch per unit effort varied from 48 to 108 kg/hr of trawling for S. salebrosa and from 40 to 87 kg/hr for A. lar, with the average catch per trawling 379 and 346 kg, and average daily catch 1380 and 1144 kg, respectively. Night catches of S. salebrosa were in 2.7 times higher than the daily catches, on average (104.7 ± 45.7 kg/hr vs 39.1 ± 31.8 kg/hr); night catches of A. lar were in 2.0 times higher than the daily catches (80.2 ± 39.0 kg/hr vs 39.6 ± 34.2 kg/hr). Portion of A. lar in the summary catches of two species varied from 4 to 88 %, on average 48 %; besides, by-catch of fish (flounders, saffron cod, pollock, cod, sculpins, herring) and humpy shrimp Pandalus goniurus was considerable. So, the portion of the most valuable species (sculptured shrimp S. salebrosa) did not exceed ⅓ of the total catch, on average. The actual annual catches exceeded significantly the recommended volumes in 2017–2019, up to 164 % for S. salebrosa and 156 % for A. lar. According to results of the trawl survey in 2019, spatial distribution patterns for S. salebrosa and A. lar coincide in details in the northern Okhotsk Sea: both species are distributed at the depth between 20–145 m, with the densest aggregations (> 60 % of both stocks) located between Bolshoi Shantar Island and the northern tip of Sakhalin, southward from 55о 30′ N, where their biomasses reach 434 kg/km2 for S. salebrosa and 68 kg/km2 for A. lar. Total commercial stocks of these species within the North Okhotsk Sea fishery district were assessed in 2019 as 16.0 . 103 t for S. salebrosa and 3.8 . 103 t for A. lar. Reproductive cycles of S. salebrosa and A. lar females in the Okhotsk Sea are fundamentally the same as the cycle of former species in Peter the Great Bay (Japan Sea), with their total duration of 48 months including 24 months for the gonads development until spawning and 24 months from the spawning to hatching of larvae. In the Okhotsk Sea, spawning of S. salebrosa and A. lar occurs most likely in spring; mass hatching of their larvae — in summer.

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Eigaard, Ole Ritzau, and Sten Munch-Petersen. "Influence of fleet renewal and trawl development on landings per unit effort of the Danish northern shrimp (Pandalus borealis) fishery." ICES Journal of Marine Science 68, no. 1 (September 7, 2010): 26–31. http://dx.doi.org/10.1093/icesjms/fsq141.

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Abstract Eigaard, O. R., and Munch-Petersen, S. 2011. Influence of fleet renewal and trawl development on landings per unit effort of the Danish northern shrimp (Pandalus borealis) fishery. – ICES Journal of Marine Science, 68: 26–31. 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, the relationship between nominal effort data as recorded in logbooks (days fishing) and effective effort is likely to have changed, so to standardize the nominal lpue time-series, trawl-size development has been taken into account using generalized linear modelling. As logbooks do not provide trawl-size information, this standardization was made possible by retrieving technical trawl and vessel data from industry order books. These data demonstrated an approximately linear relationship between vessel engine power and Pandalus trawl size, so validated the use of vessel horsepower from the logbooks as a proxy for an unknown trawl size. Standardized lpue time-series for the past 20 years indicated a lesser increase in stock size than nominal lpue, the modelling results demonstrating that vessel lpue increased by 9.5% with each 100 hp of engine power.

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Almendarez-Hernández, Luis César, Germán Ponce-Díaz, Daniel Lluch-Belda, Pablo Del Monte-Luna, and Romeo Saldívar-Lucio. "Risk assessment and uncertainty of the shrimp trawl fishery in the Gulf of California considering environmental variability." Latin American Journal of Aquatic Research 43, no. 4 (February 28, 2017): 651–61. http://dx.doi.org/10.3856/vol43-issue4-fulltext-4.

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The shrimp fishery off the Mexican Pacific coast is the country's most important fishery from the economic standpoint. However, it faces serious problems, including the fleet’s overcapitalization and age, in addition to the environmental variability that affects the size of catches. Thus, this activity depends on a variety of factors that add uncertainty to the profitability of fishing vessels. This study aims to estimate the probability of success and economic risk of "type vessels" under two different environmental variability scenarios in the Gulf of California. The results from the economic simulation pointed to the vessel type used in Guaymas (Sonora) as the most efficient one under a neutral climate change scenario, showing a homogeneous behaviour in physical characteristics and mode of operation. By contrast, under a scenario of a monotonic rise in sea surface temperature, the shrimp fishery faces a greater risk of incurring economic losses. The simulated climate behaviour scenarios revealed that the activity involves a moderate economic profitability under the neutral scenario; however, under the warming scenario, profitability may be low or even nil due to the risks and uncertainty resulting from the influence of environmental phenomena.

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EKANAYAKA, E. M. M. I., P. D. S. MADHUSHANKHA, and D. C. T. DISSANAYAKE. "By-catch from the Artisanal Shrimp Trawl Fishery off Negombo, Sri Lanka." Journal of the Indian Society of Coastal Agricultural Research 39, no. 2 (December 31, 2021): 95. http://dx.doi.org/10.54894/jiscar.39.2.2021.110541.

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Vianna, Marcelo, Acácio R. G. Tomas, and José R. Verani. "Aspects of the biology of the Atlantic Midshipman, Porichthys porosissimus (Teleostei, Batrachoididae): an important by-catch species of shrimp trawling off southern Brazil." Revista Brasileira de Oceanografia 48, no. 2 (2000): 131–40. http://dx.doi.org/10.1590/s1413-77392000000200004.

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Trawl fishing for pink shrimp (Farfantepenaeus brasiliensis and F. paulensis) catches large quantities of by-catch fish, discarded due to their having no commercial va)ue. As these species have rarely been studied, the impact of fisheries on these populations is not known. This contribution studies the biology of a species of no commercial value, the Atlantic midshipman Porichthys porosissimus. The last haul /Tom a commercial trawler, operating on the northern coast of São Paulo State and the southern coast of Rio de Janeiro State, was preserved (/Tom being discarded) and identified at the species leveI. It was observed that this fishery affects the juvenile population which is intluenced by the seasonal variation of the water masses. Growth parameters were estimated: L∞ = 37.0 cm, K = 0.285 year-1. Instantaneous mortality coefficients were estimated: 2=2.14, M=0.63, F= 1.51, S= 11.8 and E=0.71. Considering the intensive activity of the shrimp trawl tleet operating in this area, the deleterious action of trawling is considered as of high impact. The stock management measures applied for pink shrimp are without effect regarding P. porosissimus. which has its spawning period before the closed season and its recruitment peak after it. The results show overfishing and the need to apply measures to reduce trawling action, such as adequate policies, introduction of selectivity devices and the creation of exclusion zones for trawl fishing.

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Aldrin, Magne, Bjørnar Mortensen, Geir Storvik, Kjell Nedreaas, Asgeir Aglen, and Sondre Aanes. "Improving management decisions by predicting fish bycatch in the Barents Sea shrimp fishery." ICES Journal of Marine Science 69, no. 1 (November 20, 2011): 64–74. http://dx.doi.org/10.1093/icesjms/fsr172.

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Abstract Aldrin, M., Mortensen, B., Storvik, G., Nedreaas, K., Aglen, A., and Aanes, S. 2012. Improving management decisions by predicting fish bycatch in the Barents Sea shrimp fishery. – ICES Journal of Marine Science, 69: 64–74. When the bycatch of juvenile fish within the Barents Sea shrimp fishery is too large, the area is closed to fishing for a certain period. Bycatch is estimated from sampled trawl hauls, for which the shrimp yield is recorded, along with the total number of various bycatch fish species. At present, bycatch estimation is based on a simple estimator, the sum of the number of fish caught within the area of interest within a small time window, divided by the corresponding shrimp yield (in weight). No historical data are used. A model-based estimation is proposed in which spatio-temporal models are constructed for the variation in both the yield of shrimp and the amount of bycatch in space and time. The main effects are described through generalized additive models, and local dependence structures are specified through correlated random effects. Model estimation includes historical and recent data. Experiments with both simulated and real data show that the model-based estimator outperforms the present simple estimator when a low or moderate number of samples (e.g. <20) is available, whereas the two estimators are equally good when the number of samples is high.

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Dodino, Samanta, Nicolás A. Lois, Luciana Riccialdelli, Michael J. Polito, Klemens Pütz, and Andrea Raya Rey. "Sex-specific spatial use of the winter foraging areas by Magellanic penguins and assessment of potential conflicts with fisheries during winter dispersal." PLOS ONE 16, no. 8 (August 20, 2021): e0256339. http://dx.doi.org/10.1371/journal.pone.0256339.

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Magellanic penguins (Spheniscus magellanicus) disperse widely during winter and are a major consumer of marine resources over the Patagonian Shelf. Magellanic penguins were equipped with geolocators at Martillo Island in late February- early March 2017 and recaptured at the beginning of the next breeding season to recover the devices and to collect blood samples for stable carbon (δ13C) and nitrogen (δ15N) isotope analysis. We evaluated their whole winter dispersal and their trophic niche by sex during the last month of the winter dispersal. Also, we evaluated their spatial overlap with bottom trawl and shrimp fisheries using data from satellite fisheries monitoring. Penguins dispersed northwards up to 42°S and showed latitudinal spatial segregation between sexes during May to August (females were located further north than males). In contrast, during the last month of the winter dispersal females were located more southerly and showed lower trophic position than males. Also, females did not dive as deep as males during winter. We found high overlap between both fisheries and penguin’s spatial use in regions with documented interaction. However, no sex-specific statistical differences with fisheries overlap were found. Our results highlight the importance of understanding the spatial domains of each sex and assessment of their potential conflicts with bottom trawl fishery and shrimp fishery during the winter period.

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Ranjith, L., S. Ramkumar, K. Kannan, K. Vinod, K. K. Joshi, S. P. Shukla, C. S. Purushothaman, and S. K. Chakraborty. "Note on Occurrence of Jaydia queketti (Osteichthyes: Apogonidae) from the Bycatch of Tropical Trawl Fishery." Current World Environment 11, no. 2 (August 25, 2016): 604–9. http://dx.doi.org/10.12944/cwe.11.2.32.

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Three specimens of apogonids species of total length 72.69, 106.28 and 110.67 mm were caught off Tuticorin at the depths of 90-100 m as a bycatch on 1st January 2013 from the commercial trawler operated from Tuticorin Fishing Harbour, Southeast coast of India. In this paper, on the occurrence of Jaydia queketti was figured and the comprehensive diagnostic features of the recorded specimens were elucidated. The species of this genus Jaydia is distributed continentally and often caught as a bycatch from shrimp or fish trawl. These species are widely distributed in New Guinea, larger islands in the Coral Sea, Australia, Arabian Sea of India and also from Africa to Japan. Nevertheless, the present observation shows the occurrence of J. queketti from the by-catch of trawl fishery operated along Gulf of Mannar, Southeast coast of India.

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Schulte, Katharina Friederike, Andreas Dänhardt, Marc Hufnagl, Volker Siegel, Werner Wosniok, and Axel Temming. "Not easy to catch: multiple covariates influence catch rates of brown shrimp (Crangon crangon L.), potentially affecting inferences drawn from catch and landings data." ICES Journal of Marine Science 75, no. 4 (February 13, 2018): 1318–28. http://dx.doi.org/10.1093/icesjms/fsx203.

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Abstract Brown shrimps (Crangon crangon) occur in high densities in the southern North Sea and support a large, but so far unmanaged fishery with >500 vessels. Cohort-based stock assessment is not possible, and catch per unit effort from scientific surveys and commercial landings are the only variables collected. Landings per unit effort are currently used to approximate the state of stock and to trigger catch restrictions, but, although decisive in interpreting unit catches or landings, factors affecting catch rates are rarely understood. Using data from two long-term (1997–2010) scientific surveys conducted in autumn and winter, respectively, in the southern North Sea and from a vertically resolving stow net deployed at two stations in the German Wadden Sea (2005–2007), we investigate the effects of season, reproductive state, size, tidal state, daylight, and water depth on catch rates of brown shrimp. Log-linear random intercept models revealed an influence of all factors examined on the catch rate. Depth had a clear effect on the composition of size and reproductive state, supporting the hypothesis that brown shrimp utilize selective tidal stream transport to migrate to depths preferred during certain periods within their life cycle. The vertical distribution of brown shrimp across the water column revealed that on average two thirds to three quarters of the brown shrimps were located above reach of the standard shrimp catching gear. Our findings indicate that multiple factors and interactions affect catch rates of brown shrimp and, thus, need to be accounted for when interpreting unit catches or landings for management purposes. We suggest that brown shrimps are not primarily demersal, and that stock size estimates solely relying on beam trawl data may underestimate the true density of shrimps per area.

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Diamond, Sandra L. "Bycatch quotas in the Gulf of Mexico shrimp trawl fishery: can they work?" Reviews in Fish Biology and Fisheries 14, no. 2 (June 2004): 207–37. http://dx.doi.org/10.1007/s11160-004-7121-0.

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Sánchez, Julio, Omar Santana Morales, Rebeca Zertuche, and Elisa Areano. "Elasmobranch bycatch of the shrimp trawl fishery along the Pacific coast of Guatemala." Fishery Bulletin 121, no. 3 (May 25, 2023): 78–83. http://dx.doi.org/10.7755/fb.121.3.2.

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Miazaki, Lizandra Fernandes, Sabrina Morilhas Simões, Antonio Leão Castilho, and Rogério Caetano Costa. "Population dynamics of the crab Hepatus pudibundus (Herbst, 1785) (Decapoda, Aethridae) on the southern coast of São Paulo state, Brazil." Journal of the Marine Biological Association of the United Kingdom 99, no. 4 (September 5, 2018): 867–78. http://dx.doi.org/10.1017/s0025315418000620.

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AbstractThe present study investigated the population dynamics of Hepatus pudibundus in the Cananéia region, in southern São Paulo state, Brazil, focusing on population structure, growth parameters, longevity, sex ratio, reproduction and recruitment juvenile period. Sampling was performed monthly at seven stations from July 2012 to June 2014, using a shrimp fishing boat. A total of 1650 specimens were collected: 551 males and 1099 females. The males were larger than females. Reproductive females were captured throughout the study period and juveniles were captured in most months. Both of these demographic categories were positively correlated with temperature. Growth parameters showed differences between sexes: CW∞ = 78.91 mm, k = 0.0066 day−1, t0 = 0.0965 for males and CW∞ = 69.71 mm, k = 0.0053 day−1, t0 = −0.2404 for females. Longevity was estimated at 1.91 and 2.40 years for males and females, respectively. The findings provide a greater understanding of the life cycle in this species. Additionally, since trawl nets are not selective, this study also provides information for better trawl fishery management, addressing not only the target shrimp but also the by-catch species.

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Mendonça, Luana Marina De Castro, Carmen Regina Parisotto Guimarães, and Silvio Felipe Barbosa Lima. "Mollusk bycatch in trawl fisheries targeting the Atlantic seabob shrimp Xiphopenaeus kroyeri on the coast of Sergipe, northeastern Brazil." Papéis Avulsos de Zoologia 59 (August 15, 2019): e20195933. http://dx.doi.org/10.11606/1807-0205/2019.59.33.

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The malacofauna bycatch of sea-bob shrimp Xiphopenaeus kroyeri (Heller, 1862) trawl fisheries on the coast of Sergipe was studied for 5 years. The malacofauna bycatch considered was obtained in nine oceanographic sampling campaigns carried out between May 1999 and June 2003 in 18 stations distributed in six transects along depths of 10, 20 and 30 m. A total of 2,669 individuals of mollusk belonging to 54 species were captured on the 18 sea-bob shrimp trawl stations carried out along the coast of Sergipe. The considerable richness of mollusks was composed by 19 families and 31 species of gastropods, 12 families and 19 species of bivalves and 2 families and 4 species of cephalopods. The highest abundance were observed at stations 13 (373 individuals) and 16 (685 individuals) that represents the lowest depth (10 m) and the richness was higher at stations 15 and 12 (17 and 11 species, respectively) both located at the highest depth (30 m). Cephalopods had high frequency of occurrence being collected in all the stations and by far the most abundant group with a total of 2,488 individuals captured. On the other hand, gastropods (with 142 individuals found in 83.3% of stations) and bivalves (about 1% of the individuals collected) contribute with a much smaller percentage of individuals captured. Lolliguncula brevis (Blainville, 1823) was most representative cephalopod in number and frequency of occurrence. Arcidae, Conidae, Muricidae and Strombidae were the families with the higher number of species in the trawl-fishery. Among bivalves, Pitar arestus (Dall & Simpson, 1901) and Spathochlamys benedicti (Verrill & Bush [in Verrill], 1897) were the species with higher frequency of occurrence. Although the considerable sample effort and a number of mollusks captured as bycath, the richness estimators indicated that the species richness could increase with additional sampling effort in the study area. The present study expands the taxonomic alpha knowledge on the mollusk bycatch of sea-bob shrimp trawl fisheries on the northeastern coast of Brazil. However, it is of crucial importance to assess urgently the negative impacts of the sea-bob shrimp trawl fisheries on the benthic community of the entire coast of Brazil.

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Gómez-Canchong, Paúl, Renato A. Quiñones, and Luis Manjarrés. "Size structure of a heavily fished benthic/demersal community by shrimp trawling in the Colombian Caribbean Sea." Latin American Journal of Aquatic Research 39, no. 1 (November 11, 2011): 43–55. http://dx.doi.org/10.3856/vol39-issue1-fulltext-5.

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The benthic and demersal communities in the Colombian Caribbean Sea (CCS) are heavily fished by the shrimp trawling fishery, which presents very high discard levels. Here, we conducted an analysis of the size structure of these benthic and demersal communities in the northern and southern zones of the CCS. Sampling was conducted onboard shrimp trawlers throughout an entire year. No significant differences were found in the size distributions of the two zones, among sites within southern ecoregions, or among the analyzed cruises. This homogeneity in size structure is remarkable since the zones analyzed possess very different species compositions and environmental conditions. The observed size structures were adequately described by non-linear distributions rather than the traditionally employed linear normalized biomass size spectra. It is hypothesized that the non-linearity is due to the effect of fishing and particularly, of discarding. This study emphasizes the need for a greater understanding of the impacts that trawl fishing has on community size structure and the applicability of this knowledge towards fishery resource management in ecosystems with high diversity.

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Stobutzki, Ilona, Margaret Miller, and David Brewer. "Sustainability of fishery bycatch: a process for assessing highly diverse and numerous bycatch." Environmental Conservation 28, no. 2 (June 2001): 167–81. http://dx.doi.org/10.1017/s0376892901000170.

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In tropical prawn (shrimp) trawl fisheries it is daunting to assess the sustainability of bycatch species because they are diverse and there is little historical and biological information for quantitative stock assessments. We developed a process to examine the likely impact of prawn trawling on the sustainability of bycatch species and applied this to fish bycatch in the Australian Northern Prawn Fishery. The 411 fish bycatch species were ranked with respect to biological and ecological criteria that contributed to two overriding characteristics, namely first, their susceptibility to capture and mortality due to prawn trawling, and second the population's capacity to recover after depletion. The rank of each species on these two characteristics determined its relative capacity to sustain trawling, and therefore its priority for research and management. Species that were the least likely to be sustainable came from the families Apogonidae, Ariidae, Bathysauridae, Callionymidae, Congridae, Diodontidae, Labridae, Opisthognathidae, Plotosidae, Synodontidae and Tetraodontidae. These species are highly susceptible to capture by trawls, they are benthic or demersal, their primary habitat is soft sediments, and their diet may include prawns. The recovery capacity of these species is also low, with the estimated removal rate by trawling high. The species that were the most likely to be sustainable came from the families Carangidae, Clupeidae, Ephippidae, Scombridae, Sphyraenidae and Terapontidae. They are less susceptible to capture by trawls, they are generally pelagic, their primary habitat is not in trawl grounds, and they have a broad depth distribution and range in the fishery. These species also have a greater capacity to recover, as most individuals have bred before capture, and a low estimated removal rate by trawling. The final ranking of the species must be used with caution because of the assumptions made in the process. However, the process is a valuable first step towards ensuring the sustainability of the bycatch species. Because of the simplicity of the process, it can be readily used in fisheries, particularly those with diverse bycatch, to manage the sustainability of their bycatch.

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H.Cotte, Ihsan, and Mustamin Tajuddin. "PRODUKSI UDANG DAN POLA MUSIM PENANGKAPANNYA DI PERAIRAN KABUPATEN PANGKEP." JOURNAL OF INDONESIAN TROPICAL FISHERIES (JOINT-FISH) : Jurnal Akuakultur, Teknologi Dan Manajemen Perikanan Tangkap, Ilmu Kelautan 2, no. 1 (June 24, 2019): 100–110. http://dx.doi.org/10.33096/joint-fish.v2i1.40.

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Shrimp is a type of crustacean and is included in the marine fishery commoditywhich has important economic value and is currently hunted by fishermen and iscommonly found in coastal waters. The purpose of this study was to determine the ShrimpProduction and Seasonal Catching Pattern in the Waters of Pangkep Regency. Itsusefulness is as a foundation material in the use of shrimp resources in the waters ofPangkep Regency. Data collected consists of primary data and secondary data. Primarydata is obtained by direct observation in the field through a field survey method (visualrecall) to portray the conditions of crab resources. While secondary data was collectedfrom the relevant agencies according to the attributes that will be reviewed and recordeddata from collecting fishermen in the coastal areas and small islands of PangkepRegency. Shrimp production from trammel net and mini trawl catches in the waters of theSigeri District of Pangkep Regency in 2015 consisted of 706 tons of white shrimp anddogol shrimp 4,481 tons, while in 2016 706 tons of white shrimp and dogol shrimp 4,481tons. Analysis of the percentage of shrimp fishing season index in the waters of PangkepRegency, occurred in January, February, March and April. The highest percentage offishing season index occurs in January each year.

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SONG, Se Hyun, Jae Mook JEONG, Joon Taek YOO, and Hee Yong KIM. "Species composition of bycatch in the shrimp beam trawl fishery of coastal Sacheon, Korea." Journal of the Korean Society of Fisheries Technology 54, no. 3 (August 30, 2018): 204–16. http://dx.doi.org/10.3796/ksfot.2018.54.3.204.

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Journal articles on the topic 'Trawl Shrimp Fishery'

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