chthyofauna of the Duas Unas Reservoir, Jaboatão River basin, Pernambuco, Brazil: preliminary results of composition and assemblage structure

Abstract

This paper presents preliminary information on the taxonomic composition and structure of the fish assemblage of Duas Unas reservoir, located in the Jaboatão river basin, Pernambuco, Brazil. Fish samples were collected monthly from April 2009 to March 2010, using gill nets (12, 20 and 40 mm mesh sizes), with 24-hour exposure time. A total of 322 specimens belonging to 14 species, 14 genera, 10 families and 5 orders, were captured. The occurrence of three allochthonous species was registered: Plagioscion squamosissimus, Oreochromis niloticus and Cichla kelberi. The Cichlidae family was the richest (4 species), followed by Curimatidae (2), and the others were represented by only one species each. Characidae had the highest numerical abundance and
biomass, with 170 individuals and 2,574.4 g, respectively. Astyanax gr. biamculatus, Crenicichla cf. brasiliensis, Hoplias malabaricus and Steindachnerina notonota dominated numerically (81% of the total individuals captured) and in biomass (78%). Despite the low richness of the ichthyofauna surveyed, the results show the importance of the autochthonous fauna and contribute to broaden the knowledge about freshwater fish fauna from coastal basins of the state of Pernambuco.