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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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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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Pouliquen, Hervé; Le Bris, Hervé; Buchet, Vincent; Pinault, Louis. |
Marine fish farms use many antibacterial agents to prevent or fight bacterial diseases. The major part of the orally supplied drugs reach the environment, either directly due to excessive feeding and reduced appetite of the cultured fish, or indirectly after passing through the fish. Some of the drugs entering the environment may be taken up by bivalves. Comparative contamination and decontamination of Japanese oyster Crassostrea gigas and blue mussel Mytilus edulis were studied when these bivalves were kept during 10 d in seawater containing oxytetracycline (OTC) or oxolinic acid (OA) at concentrations of 0.15 and 1.50 mg l(-1). After the 10 d exposure at the seawater concentrations of 0.15 and 1.50 mg l(-1), OTC and OA concentrations in bivalve tissues... |
Tipo: Text |
Palavras-chave: Mussel; Oxolinic acid; Oxytetracycline; Oyster. |
Ano: 1996 |
URL: http://archimer.ifremer.fr/doc/00282/39359/39437.pdf |
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Saulnie, Erwan; Brind'Amour, Anik; Tableau, Adrien; Rufino, Marta; Dauvin, Jean‐claude; Luczak, Christophe; Le Bris, Hervé. |
Macrobenthic secondary production is widely used to assess the trophic capacity, health, and functioning of marine and freshwater ecosystems. Annual production estimates are often calculated using empirical models and based on data collected during a single period of the year. Yet, many ecosystems show seasonal variations. Although ignoring seasonality may lead to biased and inaccurate estimates of annual secondary production, it has never been tested at the community level. Using time series of macrobenthic data collected seasonally at three temperate marine coastal soft‐bottom sites, we assessed seasonal variations in biomass of macrobenthic invertebrates at both population and community levels. We then investigated how these seasonal variations affect... |
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Ano: 2019 |
URL: https://archimer.ifremer.fr/doc/00489/60091/63433.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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Day, Louise; Le Bris, Hervé; Saulnier, Erwan; Pinsivy, Lucas; Brind'Amour, Anik. |
Coastal and estuarine habitats function as nurseries for many commercial marine species. In these ecosystems, the hypothesis that food supply limits juvenile fish density and survival has been widely debated. Direct approaches that test this hypothesis in temperate soft-bottom nurseries are data-intensive as they rely on beam trawl to collect juvenile fish and grab or core to collect their prey within the macrobenthic community. Thus, application has often been limited to a few sampling stations and temporal snapshots. However, scientific beam trawl surveys, conducted periodically in nurseries, sample, besides juvenile fish, benthic invertebrates including potential prey species. Using data collected solely from beam trawl surveys, we tested whether food... |
Tipo: Text |
Palavras-chave: Young-of-the-year fish; Macrobenthic production; Trawl; Grab; Bay of Biscay; Quantile regression. |
Ano: 2020 |
URL: https://archimer.ifremer.fr/doc/00600/71239/69607.pdf |
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