Mexican tuna fleet dynamics of the Eastern Pacific Ocean

Abstract

It analyzes the fishing dynamics of the Mexican tuna fleet of the Eastern Tropical Pacific (ETP) and its relation with environmental signs which are used for fishing. The information comes from a systematic sample with a random start of 176 fishing cruisers, registered by the observers Mexican program (1992 to 2005). In each trip the information is generated in sequential way, allowing to suppose that this events are discreet random process and analyze as a Markov Chains. The events group in: (1) ship movement (2) sign observe and (3) fishing maneuver. The results recognize two main fishery tactics: one systematic and other random. The first one starts with a signal search (birds or marine mammals), and then a hunt and finally, a fishing throw over shoal associate with dolphins. Alternatively, the random tactics do not involve a search and have a minor probability of a throw over not associated tuna. Both fishery tactics are influenced by environmental, ecological, social, and economic factors. Different strategies were observed during an annual cycle or larger duration that is related with regional politics of fishery management derived in the ETP of the International Program of Dolphin Conservation Agreement. It was concluded that the Mexican tuna fleet dynamics of the ETP (tactics and strategies) affect the measurement of the fishery effort and the success of the trip, therefore it is necessary to evaluate its effect.