scholarly journals Effect of light-emitting diodes (LEDs) on snow crab catch rates in the Barents Sea pot fishery

2019 ◽  
Vol 76 (6) ◽  
pp. 1893-1901 ◽  
Author(s):  
Khanh Q Nguyen ◽  
Odd-Børre Humborstad ◽  
Svein Løkkeborg ◽  
Paul D Winger ◽  
Shannon M Bayse

Abstract Snow crab (Chionoecetes opilio) has become an important species for the Norwegian seafood industry since its first commercial harvest in 2012. However, periodically catch rates can be low, causing a financial strain on the fishery. Thus, improving the catch rate of existing pot designs has the potential to significantly improve the profitability of fishing enterprises. In this study, we investigated whether the addition of low-powered purple and white light-emitting diode (LED) fishing lights inside the pots could improve catch rates of snow crab in the Barents Sea. Results showed that pots with purple lights harvested a 12.8% higher catch per unit effort (CPUE; number of crab per pot) of legal-sized crab, which was significantly more than the control pots (p = 0.035); pots with white lights did not catch significantly more crab (p > 0.05). Pots equipped with only light (no bait) caught very few crabs and were not considered a viable alternative. Although purple LEDs increased snow crab capture, the economic benefits of using underwater lights in pots remains unclear given the high capital investment required.

PeerJ ◽  
2019 ◽  
Vol 7 ◽  
pp. e6874 ◽  
Author(s):  
Tomas Araya-Schmidt ◽  
Leonore Olsen ◽  
Lasse Rindahl ◽  
Roger B. Larsen ◽  
Paul D. Winger

Commercial harvesting of snow crab (Chionoecetes opilio) in the Barents Sea started in 2012 by Norwegian fishing vessels. This new fishery has significant bait requirements, representing an emerging conservation challenge. In this study, we evaluate the performance of five alternative (natural) baits manufactured from the waste stream of existing and sustainably managed harp seal (Pagophilus groenlandicus) and minke whale (Balaenoptera acutorostrata) capture. Five different types of new bait were evaluated, including seal fat (SF), seal fat with skin (SFS), seal meat with bone (SMB), whale fat with skin (WFS), and whale meat with fat (WMF). A comparative fishing experiment was conducted onboard a commercial snow crab fishing vessel in the Barents Sea (May–June, 2016) to evaluate the performance of traditional bait (squid, Illexs spp.) and alternative baits at catching snow crabs. Performance of the different baits were compared on the basis of the number of commercial crab caught per trap haul catch per unit effort (CPUE) and carapace width (CW). Our results showed that SF and SFS performed equally well to traditional bait, with no statistical difference in CPUE (p-value = 0.325 and 0.069, respectively). All of the other experimental baits significantly decreased CPUE, when compared to squid. No significant effect of bait treatment on CW was detected and the cumulative distribution of CW was the same between control traps and each of the bait treatments. Overall the results indicated that SF and SFS represent a viable alternative to replace traditional bait, addressing a key conservation challenge in this bait intensive snow crab fishery.


2009 ◽  
Vol 90 (7) ◽  
pp. 1465-1474 ◽  
Author(s):  
Miguel Neves Santos ◽  
Pedro Gil Lino

The wedge sole (Dicologoglossa cuneata, Moreau 1881) is a commercially important species for the artisanal fleet operating off the south-western Iberian Peninsula. During 2004 and 2005 a study was undertaken aiming to provide a scientific basis for management. Data collection included information on aspects of the fishery, spawning season, size at first maturity, tangle and gill-net selectivity. Seven nominal mesh sizes were used (40, 45 and 50 mm tangle nets and 40, 50, 60 and 70 mm gill-nets). Spawning lasts from December to June, with peaks in March and May. Length at first maturity for females was estimated at 18.5 cm. Catch rates decreased sharply with increasing mesh size, with tangle nets providing the highest yields. The log-normal selectivity model provided the best fit for specimens that were wedged. The higher catch-per-unit-effort of the smaller mesh sizes and the modal length of the fitted selectivity curve being below the size-at-maturity for wedge sole, suggests that the 50 mm nominal mesh size tangle net is the most appropriate for ensuring the fishery sustainability. Nevertheless, the minimum legal size should increase to at least 18 cm and a time–area closure should be implemented off the Guadiana River mouth.


Polar Biology ◽  
2019 ◽  
Vol 42 (10) ◽  
pp. 1911-1914 ◽  
Author(s):  
Sten Ivar Siikavuopio ◽  
Snorre Bakke ◽  
Bjørn Steinar Sæther ◽  
Tina Thesslund ◽  
Jørgen S. Christiansen

2020 ◽  
Vol 11 (0) ◽  
pp. 108
Author(s):  
Tore Henriksen

The introduction of a new species to the Barents Sea raises questions as to the rights and duties of states under the law of the sea to exploit, manage and conserve the species. This paper discusses three of them. The first question is whether the snow crab qualifies as a sedentary species. The entitlements and competence of states in respect of living marine resources depend on the location and the characteristics of the species. If it qualifies as a sedentary species under the law of the sea, it is subject to the sovereign rights of the coastal States. Otherwise, it is subject to the sovereign right of the coastal States as well as the freedom of fishing, dependent on its distribution. The second question is what, if any, obligations Norway as a coastal State has in respect of conservation and management of the snow crab and how Norway is complying with these obligations. This includes a discussion of whether the snow crab qualifies as an introduced, alien species and the possible implications for the obligations of the coastal State. The area of distribution of the snow crab includes waters within 200 nautical miles off Svalbard, raising a third question as to the implications of the 1920 Treaty concerning Spitsbergen (Svalbard Treaty) and in particular whether fishing vessels of Contracting parties have the right to participate in the harvest on an equal footing with Norwegian vessels. The Norwegian Snow Crab Regulations effectively reserves the harvest of snow crab for Norwegian fishing vessels. The paper discusses the implications of a recent decision by the Norwegian Supreme Court on dismissal of an appeal by a Latvian vessel and its captain convicted for illegal harvest of snow crab within 200 nautical miles off Svalbard.


Author(s):  
Denis V Zakharov ◽  
Igor E Manushin ◽  
Tatiana B Nosova ◽  
Natalya A Strelkova ◽  
Valery A Pavlov

Abstract This article investigates the diet of the snow crab (Chionoecetes opilio) and its feeding intensity in the Barents Sea. Data show that snow crab has a diverse diet that includes almost all types of benthic invertebrates living in the Barents Sea. There are differences between the diets of females and males and of juveniles and adults. Juveniles and females typically occupy shallow areas with communities of bivalve molluscs, while males typically live deeper on slopes and depressions where polychaetes and crustaceans are the most abundant groups. Stomach contents were analysed to determine the species composition and frequency of occurrence of various benthic taxa. Consumption of food was estimated and compared with data from the Russian seas of the Pacific region. The total annual consumption of macrozoobenthos by snow crab was calculated in accordance with its current distribution in the Barents Sea. Snow crab consumes at least 30 000 tonnes of benthos annually, which amounts to 0.1–0.2% of the total macrozoobenthic biomass in the investigated area. The population of snow crab causes the largest impact on the benthic communities in the northeastern part of the Barents Sea and near the south side of the Novaya Zemlya archipelago.


Polar Biology ◽  
2021 ◽  
Author(s):  
Ann Merete Hjelset ◽  
Hanna Ellerine Helle Danielsen ◽  
Jon-Ivar Westgaard ◽  
Ann-Lisbeth Agnalt

AbstractThe snow crab (Chionoecetes opilio) is an Arctic cold-water species native to the northwestern Atlantic Ocean and the northern Pacific Ocean. During the recent decades, a population has established in the Barents Sea. Several aspects of the snow crabs’ biology in this area have not been described, including time of hatching, intermoult duration of the different larval stages and larval distribution. Insight into the early-life stages might increase the understanding of the population's dynamics and further spreading in the Barents Sea as well as inform basis for making monitoring and management decisions. The present study investigated the presence and developmental stage of snow crab larva in plankton samples obtained in the central Barents Sea during a research survey in June and July 2019. Presence of snow crab larvae was confirmed through taxonomic and genetic identification. All larvae were identified as zoea I, which gives an indication of the timing of the hatching period. Morphological measurements coincide well with those reported in studies from the species native distribution range. No larvae of native Hyas spp. were found and overlap in temporal and spatial distribution is discussed. The study provides important information for development of further research into the biology of the snow crab in the Barents Sea.


Trudy VNIRO ◽  
2018 ◽  
Vol 172 ◽  
pp. 70-90 ◽  
Author(s):  
D. V. Zakharov ◽  
◽  
I. E. Manushin ◽  
N. A. Strelkova ◽  
V. A. Pavlov ◽  
...  

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