Fish community structure in four estuaries of the Central Mexican Pacific

Abstract

Community structure of estuarine fish fauna were analyzed in estuaries of Barra de Nexpa, Teolán,Mexcalhuacán and Barra de Pichi, Michoacán, Mexico for four night collections at the mouth of every estuary. Also,some physicochemical parameters were determined. Were captured a total of 2 014 individuals with a weight of10 393.42 g, belonging to 31 species and 20 families. Barra de Nexpa recorded the highest richness (S= 21) and thehighest percentage of rare species (22.6%). The most abundant species were Agonostomus monticola and Mugil curemawhile Lutjanus novemfasciatus and Dormitator latifrons recorded the highest biomass. Salinity, temperature, dissolvedoxygen and transparency, showed significant seasonal differences influenced by seasonal variation in precipitation.The composition and dominant species were different at each site and in each season while the abundance, biomassand richness showed no significant variation. The fish community was composed of marine and freshwater speciesthat use estuaries as nursery areas, marine species that are incorporated into the estuaries occasionally and estuarinespecies that are part of these ecosystems for most of its life cycle.