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| Morfin, Marie; Kopp, Dorothee; Benoît, Hugues P.; Méhault, Sonia. |
| Two vitality index approaches have been demonstrated to be good proxies of discard survival in similar fishing and environmental conditions: Reflex Action Mortality Predictors combined with injuries (RI) scores that measure the proportion of impaired reflexes and injuries, and a simpler, quicker, but less precise approach based on ordinal categories related to fish body movements and injuries (semi-quantitative assessment, SQA). This study assessed and compared these two approaches for five species (two flatfishes, skates, a seabass and a catshark) discarded in a coastal otter trawl fishery in the Bay of Biscay. All species displayed good vitality status according to both indices and were not very sensitive to the fishing nor their biological conditions.... |
| Tipo: Text |
Palavras-chave: Discard survival; Vitality indicators; Reflex Action Mortality Predictor; Bay of Biscay; Coastal otter trawl fishery. |
| Ano: 2019 |
URL: https://archimer.ifremer.fr/doc/00466/57817/60417.pdf |
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| Gatti, Paul; Méhault, Sonia; Morandeau, Fabien; Morfin, Marie; Robert, Marianne. |
| We assessed the impact of an additional 100 mm square mesh cylinder (SMC) on the selective property of the demersal whitefish trawl in the Celtic Sea. Sea trials were conducted on board a French trawler using twin trawl rigging. We tested the effects of the position of the SMC (in front of and behind the mandatory 100 mm square mesh panel) and of the insertion of a dispersive float. Selectivity analysis revealed the 50% retention length () to be greater than the Minimum Conservation Reference Sizes regardless of species (haddock, whiting or megrim) or rigging configuration. Results did not reveal a clear effect of the SMC position. However, the insertion of the float led to a decrease in selection ranges suggesting enhanced contact probabilities with the... |
| Tipo: Text |
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| Ano: 2020 |
URL: https://archimer.ifremer.fr/doc/00600/71236/73595.pdf |
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| Kopp, Dorothee; Coupeau, Yann; Vincent, Benoit; Morandeau, Fabien; Méhault, Sonia; Simon, Julien. |
| Besides understanding the effects of fishing on harvested fish stocks, effects on non-target species, habitats and seafloor integrity also need to be considered. Static fishing gears have often been mentioned as a lower impact fishing alternative to towed gears, although studies examining their actual impact on the seafloor are scarce. In this study, we aimed to describe fish trap movements on the seafloor related to soaking time and trap retrieval. Impacts on the seafloor of lightweight rectangular traps and heavier circular traps were compared. We used 3D video cameras to estimate sweeping motion on the seabed and penetration into the sediment during soaking time. The area and distance swept by each type of trap during retrieval was determined by a... |
| Tipo: Text |
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| Ano: 2020 |
URL: https://archimer.ifremer.fr/doc/00643/75526/76409.pdf |
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| Mouchet, Maud; Poirson, Manon; Morandeau, Fabien; Vogel, Camille; Méhault, Sonia; Kopp, Dorothee. |
| Improving the selectivity of a fishing gear is one technical management measure to significantly reduce by-catch of non-commercial species or undersized individuals. The efficiency of selective device is mainly estimated by comparing species composition, the biomass and length spectrum of caught individuals and escapees while the functional traits of species are rarely accounted for. Using an innovative technical device to reduce catches of undersized individuals in a multispecific bottom trawl fishery in the Bay of Biscay, namely a T90 mesh cylinder, we measured functional traits on both caught and escaped individuals of 18 species. Using a Principal Component Analysis and K-means partitioning, we clustered species into 6 groups illustrating 6 different... |
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| Ano: 2019 |
URL: https://archimer.ifremer.fr/doc/00512/62330/66588.pdf |
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