Structure and functioning of the Bay of Biscay ecosystem: A trophic modelling approach

• Published in: Estuarine, Coastal and Shelf Science
• Main Authors: Corrales, X., Preciado, I., Gascuel, Didier, D., Hernvann, Pierre‐yves, Mugerza, E., Louzao, M., Velasco, F., Doray, M., López-López, L., Carrera, P., Cotano, U., Andonegi, E., Lopez de Gamiz-Zearra, A.
• Other Authors: Basque Research and Technology Alliance (BRTA), Instituto Espagňol de Oceanografia (IEO), Consejo Superior de Investigaciones Cientificas España = Spanish National Research Council Spain (CSIC), Dynamique et durabilité des écosystèmes : de la source à l’océan (DECOD), Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE)-Institut national d'enseignement supérieur pour l'agriculture, l'alimentation et l'environnement (Institut Agro)-Institut Agro Rennes Angers, Institut national d'enseignement supérieur pour l'agriculture, l'alimentation et l'environnement (Institut Agro), Institute of Marine Sciences, University of California Santa Cruz (UC Santa Cruz), University of California (UC)-University of California (UC), Unité Sciences et Technologies Halieutiques (STH), Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)
• Format: Article in Journal/Newspaper
• Language: English
• Published: HAL CCSD 2022
• Subjects: Ecopath model; Food-web model; Ecosystem-based management; Fishing impacts; Bay of Biscay; [SDE]Environmental Sciences; Hake; Northeast Atlantic
• Online Access: https://hal.inrae.fr/hal-03760426; https://doi.org/10.1016/j.ecss.2021.107658

International audience Characterizing the structure and functioning of marine ecosystems requires a deep understanding of the dynamics of its populations and the biotic interactions among them. To this end, we developed a mass-balanced food-web model of a regional sea in the Northeast Atlantic, the Bay of Biscay (BoB), considering one of the most important anthropogenic disturbance in the area, the fishing pressure.The food-web model was performed for the whole BoB region for the first time. The model represents the ecosystems in the early 2000s, encompassing 120433 km(2) between 0 and 1000 m depth. The model was composed of 52 functional groups, ranging from primary producers to top predators, and considering both Spanish and French fishing fleets. Input data included biomass obtained locally from bottom trawl and acoustic surveys, data from stock assessment, official fishery statistics, published and unpublished data on stomach content analyses and the use of empirical equations to estimate consumption and production rates.Our results highlight the importance of the pelagic domain, since the main trophic flows are determined by the interaction between phytoplankton, zooplankton and forage fishes. The role of the detritivore pathway was also relevant due to the relatively high abundance of detritivores organisms and the large percentage of primary production flowing to the detritus. Forage fish have resulted to be a key compartment fostering the connectivity between the benthic and pelagic domains. Pelagic sharks, dolphins, anglerfish, large hake and large demersal fishes were identified as potential keystone functional groups in the BoB model. The results also showed an intense exploitation by fisheries in early 2000s. Different strategies between Spanish and French fleets were also found. French fleets were mainly focussed on low trophic level forage fish (e.g., sardine and anchovy) and had larger impacts on higher trophic levels, while Spanish fleets mostly focussed on higher trophic level forage fishes ...