scholarly journals A trap with a twist: evaluating a bycatch reduction device to prevent rockfish capture in crustacean traps

2012 ◽  
Vol 70 (1) ◽  
pp. 114-122 ◽  
Author(s):  
Brett Favaro ◽  
Stefanie D. Duff ◽  
Isabelle M. Côté

Abstract Favaro, B., Duff, S. D., and Côté, I. M. 2013. A trap with a twist: evaluating a bycatch reduction device to prevent rockfish capture in crustacean traps. – ICES Journal of Marine Science, 70:114–122. Bycatch, or the incidental capture of non-target species, occurs in fisheries around the world, with often detrimental ecological consequences. Bycatch reduction devices (BRDs) that increase catch specificity have been used successfully in some fisheries, and the development of such devices remains an important component of the global effort to reduce bycatch rates. We tested novel devices designed to exclude juvenile rockfish (Sebastes spp.) from traps used to catch spot prawns (Pandalus platyceros), a commercially important species in British Columbia, Canada. The devices included reductions in trap opening sizes and novel bent-tunnel openings. Reducing trap opening size did not affect bycatch rates of rockfish or other non-target fish species. In contrast, bent-tunnel BRDs eliminated rockfish bycatch, and two of the bent-tunnel variants also excluded other fish species. However, prawn catch rates were reduced in all modified gear, and large prawns were often excluded more than small prawns. Videos recorded in situ revealed that prawn attempts to enter traps took longer and were more likely to fail in BRD-equipped than in unmodified traps. We conclude that bent-tunnel BRDs have the potential to be useful, but improvements are needed to increase prawn catch to levels similar to that of unmodified traps.

2003 ◽  
Vol 54 (4) ◽  
pp. 575 ◽  
Author(s):  
Ellen Peel ◽  
Russell Nelson ◽  
C. Phillip Goodyear

Atlantic billfish (marlin, sailfish and spearfish) are managed under the jurisdiction of the International Commission for the Conservation of Atlantic Tunas (ICCAT). Because they are not commonly a target species, most fishing mortality is generated as a function of bycatch in various commercial fisheries. Billfish are very important species for recreational fisheries. The record indicates that ICCAT has placed its greatest emphasis on managing target fish to maximize their catch for ‘food purposes’ and has not placed the same level of emphasis on maximizing catch for ‘other purposes’, such as for the benefit of recreational fisheries.Stock assessments indicate Atlantic marlin are severely overexploited, with the rates of decline showing no signs of slowing. The primary source of billfish mortality is as bycatch in pelagic longline fisheries for tuna and swordfish. Simultaneous fishing mortality rates that will produce maximum sustainable yield (MSY) for at least one targeted tuna species is near the extinction rate for blue marlin. Failure to significantly reduce fishing mortality on marlin by restraining effort on target species has led to the collapse of both blue and white marlin stocks and, if continued indefinitely, may lead to extinction of either species. Although ICCAT's charter does not prioritize management between different types of fisheries, commercial or recreational, or among different species of fish within its authority, the de facto result of ICCAT's actions to date has relegated billfish to the role of bycatch species. The needs of the directed recreational billfish industry have been largely ignored.In the absence of responsible action by ICCAT to reduce fishing mortality on marlin, those concerned with the conservation of billfish will be forced to seek alternative conservation and management assistance through The Convention on International Trade in Endangered Species of Wild Fauna and Flora (CITES) and other protected species options. Compatible management solutions now must be identified and implemented by ICCAT if diverse fishing interests are to coexist and the stocks are to return to MSY. Time and area closures and live releases, coupled with some restraints on targeted effort, may offer a solution most acceptable to all fishing interests.


2001 ◽  
Vol 52 (4) ◽  
pp. 537 ◽  
Author(s):  
C. Bulman ◽  
F. Althaus ◽  
X. He ◽  
N. J. Bax ◽  
A. Williams

A total of 8200 stomach samples was collected from 102 fish species caught by trawl or gillnet during research surveys on the south-eastern Australian shelf from 1993 to 1996. Diet compositions were analysed based on percentages of wet weight of prey. Of the total fish examined, 70 species had sufficient stomach samples (i.e. >10) for further analysis. Ten trophic guilds were identified from cluster analysis. Benthic prey dominated the diets. However, analysis on a subset of 28 abundant species that were commercially and ecologically important, showed that pelagic prey was dominant, particularly for 12 quota species. This suggests that pelagic production contributes significantly to the trawl fishery production. Further analysis on the diets of these 28 species found that although fish was more important than invertebrate prey, there was no evidence of significant predation on commercially important species (quota species)by other fish species. A food web diagram was constructed, mostly based on the diet compositions, guild structure and relative abundance of commercially and ecologically important fish species, to show major trophic interactions of the shelf ecosystem.


2015 ◽  
pp. 4989-5003 ◽  
Author(s):  
Rocío García-Urueña ◽  
Arturo Acero P ◽  
Víctor Coronado-Carrascal

ABSTRACT Objective. Fish species community structure and benthic organisms coverage were studied in five localities in Santa Marta where the lionfish is present. Materials and methods. Abundance of fish species, including lion fish, was established using 30 m random visual censuses and video transects; trophic guilds were established according to available references. On the other hand benthic coverage was evaluated using the software Coral Point Count (CPCe) 4.0. Results. Families with higher species numbers were Serranidae, Labridae, and Pomacentridae. Lionfish abundances were low (2.6±2.1 ind/120 m2), but in any case Pterois volitans was observed as the eleventh more abundant species, surpassing species of commercial value such as Cephalopholis cruentata. Species that were found in larger numbers (>100, Thalassoma bifasciatum, Haemulon aurolineatum, Canthigaster rostrata, Abudefduf saxatilis, Chromis cyanea, and Stegastes partitus) were mainly invertebrate eaters, planctivores, and territorial herbivores. Coral coverage showed higher coral percentages in Chengue (69.9%) and Cinto (27.4%), larger sponge percentages in Morro (32.7%); Isla Aguja and Remanso showed the larger figures for abiotic substrate (41.6 and 37%, respectively); corals, sponges, and gorgonians were the components best explaining fish community, but not for the lion fish, which inhabit all studied reef formations. Conclusions. Lion fish is ranked between the 20 more abundant species, with none commercially important species larger, hence no species may qualify as a natural control. Lion fish has as well become a relatively abundant species in Santa Marta reefs, independent of benthic coverage.


2020 ◽  
Author(s):  
tom hansen ◽  
David Penman ◽  
Kevin Alan Glover ◽  
Thomas Fraser ◽  
Tone Vågseth ◽  
...  

Abstract Background: In several fish species homozygous and heterozygous clonal lines have been produced using gynogenetic and androgenetic techniques. These lines are standardized and can be reproduced over generations. In rainbow trout such lines have existed for decades and has become important research tools in genome studies as well as in studies of commercially important traits. The Atlantic salmon is one of the best studied fish species globally, but all experiments are done on fish of wild or domesticated origin and access to standardized immortal fish lines would be of great benefit. Here, we describe the protocols developed to produce mitotic gynogenes, and from these the first clonal lines in Atlantic salmon.Results: Atlantic salmon eggs fertilized with UV irradiated sperm combined with a pressure shock applied at 4700 - 4800 minC at 8 oC gave all homozygous (doubled haploid) gynogenetic progeny with high survival. From the six first maturing females, five all homozygous clonal lines were produced by meiotic gynogenesis and were verified as clonal and identical to their mother with microsatellite markers.Conclusions: We have now produced the first documented cloned Atlantic salmon lines. This work demonstrates the potential for production of further Atlantic salmon clonal lines, potentially with distinct characteristics. Such lines will provide an important resource for further elucidation of phenotypic and genetic traits in this globally important species.


Author(s):  
Samuel K. K. Amponsah ◽  
Selasi Yao Avornyo ◽  
Kofi Ferni Anyan

Population parameters for two commercially important fishes of Sciaenidae from the coastal waters of Ghana were assessed using length-frequency data obtained from August 2017 to June 2019. Samples of the assessed fish species were obtained through experimental fish trawl along the coast of Greater Accra, Ghana. Trawling was performed every quarter for an average of one hour at an average speed of 3.0 km/hr. In all, a total of 399 samples were measured and the obtained data were analyzed with FiSAT II. The assessed fish species included Pteroscion peli (165 samples) and Pseudotolithus senegalensis (234 samples). The asymptotic length (L∞) was 19.4 cm and 41.5 cm forPteroscion peli and Pseudotolithus senegalensis. Pteroscion peli and Pseudotolithus senegalensis recorded growth rate (K) of 0.48 and 0.50 per year respectively. Both assessed fish species exhibited continuous recruitment pattern with minor and major recruitment peaks. The total mortality rate (Z) was 1.86 and 1.63 per year for Pteroscion peli and Pseudotolithus senegalensis. The fishing mortality rate (F) was estimated at 0.66 and 0.63 per year for Pteroscion peli and Pseudotolithus senegalensis. The natural mortality rate (M) estimated for Pteroscion peli and Pseudotolithus senegalensis was 1.20 and 1.00 per year respectively. The exploitation rate (E) of Pseudotolithus senegalensis (0.39) and Pteroscion peli (0.36) respectively was far below the maximum exploitation rate (Emax), indicating under-exploitation of its fishery in the coastal waters of Ghana, hence the need to enhance the exploitation of these species.


Bionatura ◽  
2020 ◽  
Vol 5 (4) ◽  
pp. 1363-1370
Author(s):  
Zarni Ko Ko

A total of 48 species of fish fauna were identified during the present study period. The dominant species of fish were found under order Perciformes in all study areas. The most species composition (40) was recorded in Setse fish landing area. The commercially important fish species were mostly found in Kyaikkhami area. Moreover, 17 species of fish were exported to other regions and foreign countries. Among the fish species, species such as Threadfin (Polynemidae), Croaker (Sciaenidae), Hilsa (Clupeidae), Bombay duck (Harpadontidae), Anchovy (Engraulidae), and Pomfret fish (Stomateidae) were the most economically important species. Bombay duck and Anchovy (especially Coilia dussumieri) were more abundant (70%) at the present study sites. Harpodon nehereus and Coilia species were the leading food employed as fresh and dried for local people in the present study areas. Key words: Ichthyology, Taxonomy, Compositions, Occurrence, fish landing centers, Thanbyuzayat Township, Mon Coastal Areas.


2015 ◽  
Vol 170 ◽  
pp. 1-8 ◽  
Author(s):  
Thorben Hofmann ◽  
Michael J. Raupach ◽  
Pedro Martinez Arbízu ◽  
Thomas Knebelsberger

2020 ◽  
Author(s):  
tom hansen ◽  
David Penman ◽  
Kevin Alan Glover ◽  
Thomas Fraser ◽  
Tone Vågseth ◽  
...  

Abstract Background In several fish species homozygous and heterozygous clonal lines have been produced using gynogenetic and androgenetic techniques. These lines are standardized and can be reproduced over generations. In rainbow trout such lines have existed for decades and has become important research tools in genome studies as well as in studies of commercially important traits. The Atlantic salmon is one of the best studied fish species globally, but all experiments are done on fish of wild or domesticated origin and access to standardized immortal fish lines would be of great benefit. Here, we describe the protocols developed to produce mitotic gynogenes, and from these the first clonal lines in Atlantic salmon.Results Atlantic salmon eggs fertilized with UV irradiated sperm combined with a pressure shock applied at 4700–4800 minC at 8 oC gave all homozygous (doubled haploid) gynogenetic progeny with high survival. From the six first maturing females, five all homozygous clonal lines were produced by meiotic gynogenesis and were verified as clonal and identical to their mother with microsatellite markers.Conclusions We have now produced the first documented cloned Atlantic salmon lines. This work demonstrates the potential for production of further Atlantic salmon clonal lines, potentially with distinct characteristics. Such lines will provide an important resource for further elucidation of phenotypic and genetic traits in this globally important species.


2020 ◽  
Author(s):  
Tom Johnny Hansen ◽  
David Penman ◽  
Kevin Alan Glover ◽  
Thomas Fraser ◽  
Tone Vågseth ◽  
...  

Abstract Background In several fish species homozygous and heterozygous clonal lines have been produced using gynogenetic and androgenetic techniques. These lines are standardized and can be reproduced over generations. In rainbow trout such lines have existed for decades and has become important research tools in genome studies as well as in studies of commercially important traits. The Atlantic salmon is one of the best studied fish species globally, but all experiments are done on fish of wild or domesticated origin and access to standardized immortal fish lines would be of great benefit. Here, we describe the protocols developed to produce mitotic gynogenes, and from these the first clonal lines in Atlantic salmon. Results Atlantic salmon eggs fertilized with UV irradiated sperm combined with a pressure shock applied at 4700–4800 minC at 8 oC gave all homozygous (doubled haploid) gynogenetic progeny with high survival. From the six first maturing females, five all homozygous clonal lines were produced by meiotic gynogenesis and were verified as clonal and identical to their mother with microsatellite markers. Conclusions We have now produced the first documented cloned Atlantic salmon lines. This work demonstrates the potential for production of further Atlantic salmon clonal lines, potentially with distinct characteristics. Such lines will provide an important resource for further elucidation of phenotypic and genetic traits in this globally important species.


2008 ◽  
Vol 59 (10) ◽  
pp. 849 ◽  
Author(s):  
Anthony J. Courtney ◽  
Matthew J. Campbell ◽  
Darren P. Roy ◽  
Mark L. Tonks ◽  
Keith E. Chilcott ◽  
...  

Concern over the amount of by-catch from benthic trawl fisheries and research into the problem have increased in recent years. The present paper demonstrated that by-catch rates in the Queensland (Australia) saucer scallop (Amusium balloti) trawl fishery can be reduced by 77% (by weight) using nets fitted with a turtle excluder device (TED) and a square-mesh codend, compared with a standard diamond-mesh codend with no TED. This large reduction was achieved with no significant effect on the legal size scallop catch rate and 39% fewer undersize scallops were caught. In total, 382 taxa were recorded in the by-catch, which was dominated by sponges, portunid crabs, small demersal and benthic fish (e.g. leatherjackets, stingerfish, bearded ghouls, nemipterids, longspine emperors, lizard fish, triggerfish, flounders and rabbitfish), elasmobranchs (e.g. mainly rays) and invertebrates (e.g. sea stars, sea urchins, sea cucumbers and bivalve molluscs). Extremely high reductions in catch rate (i.e. ≥85%) were demonstrated for several by-catch species owing to the square-mesh codend. Square-mesh codends show potential as a means of greatly reducing by-catch and lowering the incidental capture and mortality of undersize scallops and Moreton Bay bugs (Thenus australiensis) in this fishery.


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