Caracterização do ictioplâncton na entrada da Baía de Guanabara (RJ)

Abstract

The present study was carried out in the entrance of the Guanabara Bay (RJ), at latitudes 22o40 and 22o57S and longitudes 43o01 and 43o16W, during June of 1993 to May of 1995. The purpose was to investigate qualitative and quantitatively the composition of the ichthyoplankton, the influence of abiotic factors and their interespecific relationships. Twenty-four samplings were realized, with six stations in the entrance of the bay. The water temperature and salinity, in the surface and near the bottom, were measured. The water transparency was measured with Secchi disc. The ichthyoplankton was collected by oblique hauls with bongo net and by horizontal hauls with neuston net. In both nets, 500 µm mesh were utilized. The nets were hauled at about ten minutes. Calibrated flowmeters were adapted in the both nets. Specific diversity of fish larvae was calculated. Interrelations of biotic and abiotic data were statistically analysed. The number of fish eggs and larvae collected by neuston net was higher, however the bongo net collected higher taxons variety. Total of 3,061,570 eggs.100m-3 and 40,492 larvae.100m-3 were collected. In the fish eggs collected, 40% were the Engraulidae family. Two species were identified, Anchoa lyolepis was more frequent during the two years and more abundant in the winter periods, while Cetengraulis edentulus was not frequent all the year and presented high abundances in the summer periods. In relation to fish larvae, a total of 35 families and 42 species were identified. The species: Harengula jaguana, Parablennius pilicornis, Blenniidae Tipo 1, Anchoa lyolepis, Cetengraulis edentulus, Haemulidae, Micropogonias furnieri, Trachinotus carolinus, Chaetodipterus faber, Achirus lineatus, Abudefduf saxatilis, Dactyloscopus sp., Eucinostomus sp. e Diapterus sp. were the more abundant from the beginning of spring to the end of summer. The species C. edentulus, Gobiesox strumosus A. lineatus, Etropus crossotus, Acanthostracion quadrico