The ecological role of opisthonema libertate and cetengraulis mysticetus on ecosystem order in the southeastern Gulf of California, Mexico

Opisthonema libertate (Pacific thread herring) and Cetengraulis mysticetus (Pacific anchovy) are the two most important herring stocks exploited in the south- eastern Gulf of California (SGC). The certification of these stocks is currently planned for achieving sustainable fisheries. This study analysed the role of these two species in the structure, organization and functioning of the ecosystem in this region. Twenty-four indicators of the ecosystem’s structure and its organization were obtained based on the output of an Ecopath model of the SGC. The relationships of the functional groups with the ecosystem’s indicators were identified using multivariate statistical techniques, and the results indicated similar roles for the Pacific thread herring and the Pacific anchovy in the ecosystem of the SGC. Both species make large contributions to the maintenance of the ecosystem’s order (i.e., its structure and organization). These results are directly related to one of the criteria that are evaluated by the Marine Stewardship Council’s certification process. Defining the remaining biomass level at sea after fishing would guarantee the sustainability of fisheries in the ecosystem.