Interactions between a natural food web, shellfish farming and exotic species: The case of the Bay of Mont Saint Michel (France)
|Author(s)||Arbach Leloup F.1, Desroy Nicolas2, Le Mao Patrick2, Pauly D.3, Le Pape Olivier1|
|Affiliation(s)||1 : Agrocampus Rennes, Lab Ecol Halieut, F-35042 Rennes, France.
2 : IFREMER, Lab Cotier Environm Resources, F-35402 St Malo, France.
3 : Univ British Columbia, Ctr Fisheries, Vancouver, BC V6T 1Z4, Canada.
|Source||Estuarine, Coastal and Shelf Science (0272-7714) (Elsevier), 2008 , Vol. 76 , N. 1 , P. 111-120|
|WOS© Times Cited||30|
|Keyword(s)||Mont Saint Michel Bay, Crepidula fornicata, invasive species, shellfish farming, trophic model, Ecopath|
|Abstract||To ensure sustainable uses of the coastal zone, an integrated ecosystemic approach and ecosystem models are required to frame ecological processes and evaluate environmental impacts. Here, a mass-balance trophic (Ecopath) model of the Mont Saint Michel Bay (MSMB) was developed, to analyze the bay's functioning as an ecosystem. This bay, intensively exploited by fishing and for shellfish farming, is also suffering from the proliferation of the gastropod Crepidula fornicata, an exotic species.The MSMB model has 18 compartments, from the primary producers to top predators, and emphasizes the large biomass of filter feeders. The model identified the MSMB as a highly productive ecosystem controlled largely from the bottom-up, and strongly impacted by huge biomasses of filter feeders. However, the low transfer efficiency rates imply that a large part of the primary production is not transferred upward to higher trophic levels, but is lost in high hydrodynamic exchanges and in the trophic impasse represented by a large biomass of Crepidula fornicata.