Fish temporal variation in different ontogenetic stages in a sheltered beach of the Baía Norte, Southern Brazil

Abstract

In beach environment daily shifts of fishes have been related to their physiological and ecological needs. On the other hand, the effect of ontogenetic changes in diurnal movement of fish fauna in this region is poorly known. The objective of this study was to evaluate the diel and seasonal variation of three ontogenetic stages of the ichthyofauna in a sheltered beach of the Baía Norte of Florianópolis. A capéchade net was armed and set for 48 hours (within one month periods) at a depth of 0.5 m to 2 m, in each sampling, with harvests performed twice at both dawn and dusk, totaling four monthly samples during an annual cycle. The results indicate that ontogenetic changes did not influence the diel occupancy of most species. The Índio beach showed high richness and juvenile abundance, with the largest number of juvenile fishes in the summer and fall. Adults were abundant in spring and summer. Among the species with highest juvenile catch, Genidens barbus, Micropogonias furnieri, Sphoeroides testudineus and Selene vomer showed residence all year round, with an increase in the mean abundance in the hottest period of the year. The increase in the mean abundance of adults was positively correlated with rainfall and seems to coincide with the spawning period of most species

Keywords: ichthyofauna, temporal cycles, juvenile fishes.