Interactions among shrimp and "catarina" clam fisheries at Magdalena Bay, Baja California Sur Mexico

In order to provide information to strengthen the implementation of management measures as part of the ecosystem, we analyzed the fleet operation dynamics of "Catarina" clam and shrimp, as well as the overlap of fishing seasons and zones at Magdalena-Almejas Bay region. Maps were created delimiting fishing zones, considering the lagoon complex physiographic features, fishing gear in use, depth and the spatial and temporal distribution of catches. The validated results by a study of local knowledge help us to understand how fleets operate during periods of interaction between these fisheries, the perceptions, preferences and tactics of producers to these events. It was found that economic units have permits to exploit multiple resources and must decide in the medium term which fishing gear to invest and in the short term which fishery and area to participate. The impacts of direct interactions are reduced by the users trading strategies, who to choose among more than an open season, use the abundance of the resource as the main criterion (65%), followed by the beachfront price paid for the resource (15%). The spatial interactions analyzed in thematic map of frequency of use showed congestion and distribution problems that tend to worsen over time so it is recommended to move from the management scheme of one fishery to multi fisheries within a region or ecosystem.