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| Registros recuperados: 38 | |
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| Kopp, Dorothee; Morandeau, Fabien; Mouchet, Maud; Vogel, Camille; Mehault, Sonia. |
| In the Bay of Biscay, the selective properties of otter trawls have mainly been studied with regard to single species. However, for bottom trawl multispecific fisheries targeting fish, it remains challenging to find a selective device capable of limiting catches of small individuals of several species without commercial losses. The present study focuses on an innovative technical solution to reduce catches of undersized individuals in a multispecies bottom trawl fishery in the Bay of Biscay. We tested a cylinder made of 100-mm diamond meshes turned at 90°, namely T90 inserted in the extension piece. We present the selectivity results obtained for six commercial species. This device allows the escape of small Solea solea, Trachurus trachurus and... |
| Tipo: Text |
Palavras-chave: Gear technology; Covered codend; Turned mesh; Escape; Discard ban. |
| Ano: 2018 |
URL: https://archimer.ifremer.fr/doc/00439/55026/56487.pdf |
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| Walters, Andrea; Robert, Marianne; Cresson, Pierre; Le Bris, Hervé; Kopp, Dorothee. |
| Quantification of the physical and biological factors that influence the spatial structuring of food webs is central to inform effective resource management. We used baseline‐corrected stable isotope ratios (δ13C and δ15N) of 63 invertebrate and fish to investigate food web structure across a continental shelf gradient—the Celtic Sea Shelf in the Northeast Atlantic Ocean. Hierarchical clustering on δ13C and δ15N showed that the shelf food web is characterized by four trophic levels with trophic groups spread across pelagic and benthic trophic pathways. Four biomass‐weighted isotopic diversity metrics provided indicators on the status of the system, showing a relatively complex food web with high trophic redundancy at intermediate trophic levels suggesting... |
| Tipo: Text |
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| Ano: 2021 |
URL: https://archimer.ifremer.fr/doc/00693/80500/83696.pdf |
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| Merillet, Laurene; Mouchet, Maud; Robert, Marianne; Salaun, Michele; Schuck, Lucie; Vaz, Sandrine; Kopp, Dorothee. |
| Trawling activities are considered to be one of the main sources of disturbance to the seabed worldwide. We aimed to disentangle the dominance of environmental variations and trawling intensity in order to explain the distribution of diversity patterns over 152 sampling sites in the French trawl fishing-ground, the Grande Vasière. Using a towed underwater video device, we identified 39 taxa to the finest taxonomic level possible, which were clustered according to their vulnerability to trawling disturbance based on functional traits. Using generalized linear models, we investigated whether the density distribution of each vulnerability group was sensitive to trawling intensity and habitat characteristics. Our analyses revealed a structuring effect of depth... |
| Tipo: Text |
Palavras-chave: Bay of Biscay; Biodiversity; Bottom trawl; Fishing; Underwater video; Vulnerability. |
| Ano: 2018 |
URL: http://archimer.ifremer.fr/doc/00406/51741/52436.pdf |
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| Bird, Christopher S.; Verissimo, Ana; Magozzi, Sarah; Abrantes, Katya G.; Aguilar, Alex; Al-reasi, Hassan; Barnett, Adam; Bethea, Dana M.; Biais, Gerard; Borrell, Asuncion; Bouchoucha, Marc; Boyle, Mariah; Brooks, Edward J.; Brunnschweiler, Juerg; Bustamante, Paco; Carlisle, Aaron; Catarino, Diana; Caut, Stephane; Cherel, Yves; Chouvelon, Tiphaine; Churchill, Diana; Ciancio, Javier; Claes, Julien; Colaco, Ana; Courtney, Dean L.; Cresson, Pierre; Daly, Ryan; De Necker, Leigh; Endo, Tetsuya; Figueiredo, Ivone; Frisch, Ashley J.; Hansen, Joan Holst; Heithaus, Michael; Hussey, Nigel E.; Iitembu, Johannes; Juanes, Francis; Kinney, Michael J.; Kiszka, Jeremy J.; Klarian, Sebastian A.; Kopp, Dorothee; Leaf, Robert; Li, Yunkai; Lorrain, Anne; Madigan, Daniel J.; Maljkovic, Aleksandra; Malpica-cruz, Luis; Matich, Philip; Meekan, Mark G.; Menard, Frederic; Menezes, Gui M.; Munroe, Samantha E. M.; Newman, Michael C.; Papastamatiou, Yannis P.; Pethybridge, Heidi; Plumlee, Jeffrey D.; Polo-silva, Carlos; Quaeck-davies, Katie; Raoult, Vincent; Reum, Jonathan; Torres-rojas, Yassir Eden; Shiffman, David S.; Shipley, Oliver N.; Speed, Conrad W.; Staudinger, Michelle D.; Teffer, Amy K.; Tilley, Alexander; Valls, Maria; Vaudo, Jeremy J.; Wai, Tak-cheung; Wells, R. J. David; Wyatt, Alex S. J.; Yool, Andrew; Trueman, Clive N.. |
| Sharks are a diverse group of mobile predators that forage across varied spatial scales and have the potential to influence food web dynamics. The ecological consequences of recent declines in shark biomass may extend across broader geographic ranges if shark taxa display common behavioural traits. By tracking the original site of photosynthetic fixation of carbon atoms that were ultimately assimilated into muscle tissues of 5,394 sharks from 114 species, we identify globally consistent biogeographic traits in trophic interactions between sharks found in different habitats. We show that populations of shelf-dwelling sharks derive a substantial proportion of their carbon from regional pelagic sources, but contain individuals that forage within additional... |
| Tipo: Text |
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| Ano: 2018 |
URL: https://archimer.ifremer.fr/doc/00420/53141/54249.pdf |
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| Day, Louise; Kopp, Dorothee; Robert, Marianne; Le Bris, Hervé. |
| Human activities affect continental shelves, especially due to the harvest of living marine resources. Understanding their functioning and dynamics has become a growing concern in recent decades, especially through use of trophic modelling approaches. Studying the feeding ecology of key component species also improves this understanding by providing accurate information on trophic processes, particularly the dependence on trophic pathways. This study focuses on the trophic ecology of four large gadiforms (cod, haddock, whiting and hake) found on the continental shelf of the Celtic Sea. The study combines information on recently ingested prey (gut content analysis) and a more integrated indicator of food sources (stable isotope analysis). Two size classes... |
| Tipo: Text |
Palavras-chave: Celtic Sea; Feeding; Gut content; Stable isotopes; Ontogeny; Habitat comparison. |
| Ano: 2019 |
URL: https://archimer.ifremer.fr/doc/00486/59742/62839.pdf |
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| Mehault, Sonia; Morandeau, Fabien; Kopp, Dorothee. |
| Le taux de survie des langoustines rejetées après chalutage est estimé aujourd’hui à 51% contre 30% dans les années 70-80. Cette valeur estimée expérimentalement est donc un majorant du taux de survie réel qui est impacté par de nombreux facteurs difficilement quantifiables. La mortalité des rejets peut être réduite par l’utilisation de table de tri et de goulotte d’évacuation lors du traitement de la capture. Cependant, la survie des langoustines au-delà du moment de leur remise à l’eau est difficile à évaluer, mais il est certain que leurs chances de survie sont réduites si elles sont rejetées en dehors des secteurs où les individus pourront retrouver un habitat qui leur est favorable. |
| Tipo: Text |
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| Ano: 2015 |
URL: https://archimer.ifremer.fr/doc/00299/41018/40122.pdf |
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| Kopp, Dorothee; Lefebvre, Sebastien; Villanueva, Ching-maria; Ernande, Bruno. |
| Determining the organisation of natural communities as well as their ability to face environmental changes are at the core of many ecological studies. In that aim, many studies tried to describe trophic interactions between species and quantify their strength in ecological networks, the multiplicity of trophic links being assumed to promote the stability and persistence of communities. In marine ecosystems, the study of trophic relationships has extensively benefited from the development of analytical tools like stable isotopes analysis (SIA) as dietary tracers. Particularly, δ15N values are useful in estimating intra- and inter-specific trophic level variations while δ13C values will indicate variation in the source of organic matter. Here, we proposed to... |
| Tipo: Text |
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| Ano: 2012 |
URL: http://archimer.ifremer.fr/doc/00163/27394/25624.pdf |
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| Vincent, Benoit; Simon, Julien; Vacherot, Jean-philippe; Morandeau, Fabien; Larnaud, Pascal; Kopp, Dorothee; Mehault, Sonia; Morfin, Marie; Savina-rolland, Marie; Marc, Emilie. |
| The Lorient flume tank is an hydrodynamic facility available for any qualification and observation of submerged objects in still or moving water. It is a closed loop circulating tank filled with fresh water. The fluid is moved with a 70 kW pump-motor with a velocity between 0 and 1 m/s and homogenized with a series of pressure drop systems. The overall dimensions are 24.50 m long, 7.50m wide and 3.30 m high. The part where experiments can be set up is 12m long, 2.6 m wide and 1.5 m deep. A mobile bottom belt can be synchronized with the water flow velocity and enables to simulate the seabed velocity relatively to a towed object. The overall process of the facility is controlled by a user friendly interface. |
| Tipo: Text |
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| Ano: 2018 |
URL: http://archimer.ifremer.fr/doc/00436/54803/56299.pdf |
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| Lefebvre, Sebastien; Giraldo, Carolina; Kopp, Dorothee; Cresson, Pierre; Travers-trolet, Morgane; Ernande, Bruno. |
| Trophic relationships play a crucial role in shaping community structure and ecological functions in marine ecosystems. Studying food-web variation along environmental gradients is still in its infancy and provides new insights in understanding how abiotic variables shape species interactions. In epicontinental seas, benthic-pelagic couplings modify predator-prey relationships and lead to entangled trophic networks. Here, we assumed that depth affects benthic-pelagic couplings’ strength and we investigated depth-related changes in the feeding patterns of fish in the whole English Channel (EC) used as a case study. Gut content and stable carbon and nitrogen isotopes of 33 fish species were collected between 5-100 m depth in 2009 and in 2014. Samples from... |
| Tipo: Text |
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| Ano: 2018 |
URL: http://archimer.ifremer.fr/doc/00455/56634/58370.pdf |
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| Mehault, Sonia; Morandeau, Fabien; Kopp, Dorothee. |
| The new Common Fisheries Policy may exempt some species from the landing obligation if a high survival rate can be demonstrated among discards. This study focuses on the survival capacity of Nephrops norvegicus discarded from trawlers of the Bay of Biscay (France). Three sea trials were conducted on board 3 commercial trawlers and 15 fishing operations were sampled. The vitality of Nephrops was classed into three categories (healthy, moribund or dead) before release at sea and samples of healthy and moribund individuals were kept in captivity on Nephrops grounds for three days. A Generalised Linear Model was used to examine the variability in the proportion of healthy Nephrops discarded, which was significantly influenced by tow duration, duration of air... |
| Tipo: Text |
Palavras-chave: Vitality; Captivity; South western waters; Bottom trawl; GLM. |
| Ano: 2016 |
URL: http://archimer.ifremer.fr/doc/00346/45695/45355.pdf |
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| Kopp, Dorothee; Robert, Marianne; Chouvelon, Tiphaine; Mehault, Sonia. |
| For the ecosystem approach to fisheries management, understanding population dynamics and ecosystem resilience in response to the landing obligation acted by the reform of the European Common Fishery Policy (CFP) is currently an important avenue of research. This study attempts to assess the impact of the new CFP on marine food webs. Total carbon and nitrogen loss induced by a discard ban were estimated for the ecosystem of the Bay of Biscay based on French At-Sea Observer data and carbon and nitrogen content of discarded fish. Changes in predator diets were estimated by comparing two Bayesian mixing models, one mimicking the current situation and the second the application of the new CFP (removing the discarded species that would be landed from the... |
| Tipo: Text |
Palavras-chave: Fishery discards; Discard ban; Bay of Biscay; Organic input; Resource use. |
| Ano: 2016 |
URL: http://archimer.ifremer.fr/doc/00308/41895/41229.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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| Issac, Pierre; Robert, Marianne; Le Bris, Hervé; Rault, Jonathan; Pawlowski, Lionel; Kopp, Dorothee. |
| We used stable isotope ratio and gut content analyses to determine and compare the feeding ecology of two commercially important predator species, Lophius piscatorius and Lophius budegassa in the Celtic sea, where data concerning their trophic ecology remain sparse. This study included two areas and two size-classes, showing that anglerfish in the Celtic sea are mainly piscivorous top predators as observed in other marine waters. However, a substantial part of the diet of the fish in the small size classes consists of benthic macro-invertebrates, mainly Crustaceans. Despite the common knowledge that they are opportunistic predators that display a low degree of prey selectivity, our results suggest that the two species have different trophic niches when... |
| Tipo: Text |
Palavras-chave: Lophius; Gut content; Stable isotopes; Trophic niche; Trophic segregation; Top predator. |
| Ano: 2017 |
URL: http://archimer.ifremer.fr/doc/00395/50614/51326.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... |
| Tipo: Text |
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| Ano: 2019 |
URL: https://archimer.ifremer.fr/doc/00512/62330/66588.pdf |
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| Giraldo, Carolina; Ernande, Bruno; Cresson, Pierre; Kopp, Dorothee; Cachera, Marie; Travers-trolet, Morgane; Lefebvre, Sebastien. |
| Depth is one of the environmental variables influencing the structure of marine food webs by directly or indirectly influencing benthic-pelagic coupling and predator-prey relationships. In shallow waters, the high degree of connectivity between pelagic and benthic networks results in complex systems with multiple interactions. Digestive tract (DT) and stable isotope (SI) analyses were used to investigate depth-related changes in feeding patterns for 33 fish species (eastern English Channel [EEC]) collected between 5 m and 80 m depth. Fish species were first arranged into functional groups based upon trophic and habitat similarities. DTs were used to determine the general topology of the food web and SIs were used to estimate the contributions of different... |
| Tipo: Text |
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| Ano: 2017 |
URL: https://archimer.ifremer.fr/doc/00386/49711/52255.pdf |
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| Registros recuperados: 38 | |
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