Structure of the ichthyoplanktonic assemblage in two tropical estuaries of Pernambuco (Brazil), subject to different hydrological conditions

Abstract

This study aimed to compare the structure of the ichthyoplanktonic assemblage in two estuarine complexes of Pernambuco (Rio Formoso and Suape), and relate it to the variation of hydrological factors. Samples were taken bimonthly (April 2012 to February 2013) with a plankton net (500 ?m mesh size). A total of 2,383 fish larvae was recorded for the two estuaries. The identified larvae belong to 34 families, 30 genera and 13 species. Families with higher participation in both estuaries were Engraulidae (27%), Clupeidae (23%), Gobiidae (20%) and Sciaenidae (7%), followed by Belonidae, Pomacentridae, Carangidae (3% each) and Achiridae (2%), while the remaining taxa represented 12%. The high larval density of Clupeidae and Engraulidae suggests that there is an intense reproductive activity of these fishes in Rio Formoso and Suape, Clupeiformes being the most abundant group in both estuaries. The two estuarine complexes have similar larval fish assemblages with higher contribution of marine families in Suape, where the highest salinity was recorded. The estuary of Rio Formoso showed greater richness, diversity and equitability, thus indicating it has a greater ecological stability than Suape.