versão On-line ISSN 1676-0611
VASCONCELLOS, Ruan Managna; SANTOS, Joaquim Neto de Sousa; SILVA, Márcio de Araújo e ARAUJO, Francisco Gerson. Effect of the wave exposure gradient on juvenile fish community in sandy beaches of the Rio de Janeiro City, Brazil. Biota Neotrop. [online]. 2007, vol.7, n.1. ISSN 1676-0611. http://dx.doi.org/10.1590/S1676-06032007000100013.
Distribution and abundance of the ichthyofauna of surf zone in sandy beaches of the Rio de Janeiro Municipality, Brazil, were studied aiming to detect seasonal and wave exposure gradient influences on the fish community structure. Quarterly samplings were performed at 10 sites according to the exposure degree (sheltered, exposed and very exposed) between January and November 2004, by using beach seines with hauls carried out perpendicular to the coastline. A total of 6,464 fishes in 38 species and 22 families were identified, mainly juveniles or small sized individuals. The families Clupeidae, Carangidae and Sciaenidae amounted to 79% of the total fish number and 61% of the total biomass. The following species amounted to 81% of the total weight were: Harengula clupeola (36%), Orthopristis ruber (14%), Mugil liza (10%), Trachinotus goodei (8%), Trachinotus carolinus (7%) and Umbrina coroides (6%). Three species showed the highest relative abundance, contributing each one more than 10% of the total number (Harengula clupeola, Umbrina coroides, e Trachinotus carolinus); but only T. carolinus showed a clear pattern, being more abundant in the sheltered beaches. The highest CPUEs (number of individuals and biomass) and number of species values occurred in the sheltered beaches (p < 0.05); none of these indicators showed significant seasonal differences (p > 0.05), although some trends were detected. The wave exposure degree was confirmed as a primary factor influencing the fish community structure, with sheltered sites probably associated to higher plankton availability, lesser turbulence and more substrate stability.
Palavras-chave : sandy beach; surf zone; fish; ichthyofauna; Rio de Janeiro.