Abundância, distribuição e desenvolvimento das fases iniciais de peixes no estuário do Rio Formoso,Pernambuco - Brasil

Abstract

Qualitative and quantitative surveys of ichthyoplankton are essential to understand the role of eggs and larvae in the pelagic food web and to indicate preferred spawning season and season. Salinity variation may be a primary factor influencing patterns of fish distribution along gradients of an estuarine environment, as well as temperature. Therefore, to better understand the variability of an ecosystem's processes, an analysis of these at different scales of space and time is fundamental. This work aimed at the identification, statistical, biological and ecological evaluation of the ichthioplankton assembly in the Rio Formoso estuary; Being one of the few that is in good condition in the state of Pernambuco. The studied area corresponds to that covering the estuarine complex of the Formoso river, south coast of state (08º 35 '00''S and 035º 95 '00''W), 85 Km from the city of Recife. The material was collected in the period from January to December / 2001 using a 0.5 mm-mesh conical-cylindrical mesh, 30 cm in diameter and 2.0 m in length, and a flowmeter was attached to it. The collections were carried out in the different phases and periods of tides, covering all the dynamics of the waters in the estuary. In the 39 collection campaigns carried out, 399 trawls were carried out, capturing a total of 2,875 fish larvae, 4,120 eggs and 691 juveniles. The occurrence of 30 taxa was identified. Those with the highest median abundance were: Anchovia clupeoides, Atherinella brasiliensis, Bathygobius soporator, Bairdiella ronchus and Gerreidae, with relative participation of 27%, 14%, 12%, 9% and 7%, respectively; Also occurring some species of oceanic habit, such as Hirundichthys affinis, and others difficult to catch, such as Microdesmus bahianus.