Fisheries Management of Mexican and Central American Estuaries

Abstract

The estuarine system of Marismas Nacionales (Pacific coast of Mexico) is a Biosphere Re-serve that is considered to be the most extensive mangrove region in the American Pacific, and an important region for artisanal fisheries since prehispanic times. Significant hydro-logical changes occurred in this region after 1976 when an artificial channel was construct-ed to connect the sea to the main body of the estuary. The channel was originally build to be 40 m wide by 2 m deep, but erosion of the sand barrier (consequence of strong ebb currents) caused the formation of a channel that is presently more than 700 m wide and 20 m deep. The consequent hydrological shift caused the mortality of more than 15,000 ha of man-groves; more than 33 % of the mangroves were affected by 1999, and it is considered that the process of deterioration is still happening. On the other hand the opening of the artificial channel improved the shrimp and finfish fisheries in the region: the number of fishing com-munities increased, as did the shrimp and fish landings, and large populations of pershell (Atrina maura) settled in the region. Several publications state the importance of mangrove as a key habitat for sustainable fisheries, but environmental conditions in some mangrove areas can be extremely difficult for the survival of fishes, crustaceans and mollusks (i.e. due to oxygen depletion). Thus, it seems that the role of mangroves is more related to the support of fisheries in surrounding habitats such as tidal channels, intertidal sand banks, seasonal flood plains, coastal lagoons and adjacent marine areas than " in situ " mangroves.