Lower trophic levels and detrital biomass control the Bay of Biscay continental shelf food web: Implications for ecosystem management

• Published in: Progress in Oceanography
• Main Authors: Lassalle, Géraldine, Lobry, Jérémy, Le Loc’h, François, Bustamante, Paco, Certain, Grégoire, Delmas, Daniel, Dupuy, Christine, Hily, Christian, Labry, Claire, Le Pape, Olivier, Marquis, Elise, Petitgas, Pierre, Pusineri, Claire, Ridoux, Vincent, Spitz, Jérôme, Niquil, Nathalie
• Other Authors: LIttoral ENvironnement et Sociétés (LIENSs), La Rochelle Université (ULR)-Centre National de la Recherche Scientifique (CNRS), Ecosystèmes estuariens et poissons migrateurs amphihalins (UR EPBX), Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA), Ecosystèmes Marins Exploités (UMR EME), Institut de Recherche pour le Développement (IRD)-Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Université de Montpellier (UM), Unité Dynamiques des Écosystèmes Côtiers (DYNECO), Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER), Laboratoire des Sciences de l'Environnement Marin (LEMAR) (LEMAR), Institut de Recherche pour le Développement (IRD)-Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Université de Brest (UBO)-Institut Universitaire Européen de la Mer (IUEM), Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS), Écologie et santé des écosystèmes (ESE), Institut National de la Recherche Agronomique (INRA)-AGROCAMPUS OUEST, Unité Écologie et Modèles pour l'Halieutique (EMH), Office National de la Chasse et de Faune Sauvage, Cellule Technique Océan Indien, Centre de Recherche sur les Mammifères Marins (CRMM), La Rochelle Université (ULR), French program PNEC”Chantier Golfe de Gascogne”;EU FP7 grant FACTS (Forage Fish Interactions);Grant Agreement No. 244966;European project REPRODUCE (EratNet-Marifish, WP7, European Project: 244966,EC:FP7:KBBE,FP7-KBBE-2009-3,FACTS(2010)
• Format: Article in Journal/Newspaper
• Language: English
• Published: HAL CCSD 2011
• Subjects: ecosystem management; bottom-up control; multispecies fisheries; Ecopath; aquatic communities; trophic structure; continental shelf; Bay of Biscay; North-East Atlantic; [SDE]Environmental Sciences; [SDV.TOX.ECO]Life Sciences [q-bio]/Toxicology/Ecotoxicology; North East Atlantic
• Online Access: https://hal.science/hal-00683349; https://hal.science/hal-00683349/document; https://hal.science/hal-00683349/file/Lassalle_etal_2011.pdf; https://doi.org/10.1016/j.pocean.2011.09.002

[Departement_IRSTEA]Eaux [TR1_IRSTEA]QUASARE International audience The Bay of Biscay (North-East Atlantic) has long been subjected to intense direct and indirect human activities that lead to the excessive degradation and sometimes overexploitation of natural resources. Fisheries management is gradually moving away from single-species assessments to more holistic, multi-species approaches that better respond to the reality of ecosystem processes. Quantitative modelling methods such as Ecopath with Ecosim can be useful tools for planning, implementing and evaluating ecosystem-based fisheries management strategies. The aim of this study was therefore to model the energy fluxes within the food web of this highly pressured ecosystem and to extract practical information required in the diagnosis of ecosystem state/health. A well-described model comprising 30 living and two non-living compartments was successfully constructed with data of local origin, for the Bay of Biscay continental shelf. The same level of aggregation was applied to primary producers, mid-trophic-levels and top-predators boxes. The model was even more general as it encompassed the entire continuum of marine habitats, from benthic to pelagic domains. Output values for most ecosystem attributes indicated a relatively mature and stable ecosystem, with a large proportion of its energy flow originating from detritus. Ecological network analysis also provided evidence that bottom-up processes play a significant role in the population dynamics of upper-trophic-levels and in the global structuring of this marine ecosystem. Finally, a novel metric based on ecosystem production depicted an ecosystem not far from being overexploited. This finding being not entirely consistent over indicators, further analyses based on dynamic simulations are required.