Fish communities of two tidal creeks in the Pinheiros bay, state of Paraná, southern Brazil

Abstract

Tidal creeks are meandering channels that are highly influenced by tidal changes and can experience substantial variation in salinity and depth over the course of the same day. The goal of the present work is to survey the ichthyofauna associated with these environments and to assess seasonal differences in their composition in tidal creeks of the euhaline sector of the estuary of the Paranagua. Two tidal creeks of the Pinheiros bay were sampled monthly at the same time using fyke nets. A total of 13,755 fish from 55 species and 27 families were captured. Only the clupeiforms Anchoa parva, Cetengraulis edentulus, and Harengula clupeola showed substantial seasonal variation in abundance, being most frequent during the fall and its adjacent months. Benthophagic individuals such as Sphoeroides testudineus, Bairdiella ronchus and Cathorops spixii were the most dominant in terms of biomass and were present all year long, although with irregular abundance. Sciaenid species were most frequent in the fall and winter, both as juveniles and as adults. The spring and part of the fall were characterized by the highest number of species with mature gonads, whereas the fall was the most important recruitment period, causing an increase in the richness indices and in the number of captured individuals. Tidal creeks were intensively visited by fish of all trophic levels and ages. These results, together with the high richness and diversity indices, corroborate the importance of tidal creeks for the preservation of estuarine environments.