Uso de marcação e recaptura para estimar a abundância e densidade de Trichomycterus brasiliensis (Siluriformes, Trichomycteridae) em poções do córrego da Bexiga, Carrancas, Minas Gerais, Brasil

Abstract

We used mark-recapture to estimate abundance and density of Trichomycterus brasiliensis in different pools at the Bexiga stream, Carrancas, Minas Gerais. Samplings were performed October 12–24, 2008. We marked a total of 91 individuals of T. brasiliensis, and 49.4% were recaptured in the second sampling. Regarding the efficiency of the sampling gear, the results show that 62.2% of the estimated numbers of individuals were caught in each pool. About 83% of the fish were captured at the margins. The average species abundance and density was estimated between 38.5 and 0.7/m2 , respectively. There was no correlation between abundance and morphometric characteristics of the pools. However, the density was negative and significantly correlated with the area. In addition, the average size of the individuals of each pool was significantly correlated with the area and volume. These results are corroborated by significant difference of mean sizes of the individuals registered in each environment, indicating a strong tendency for larger individuals to be captured in large-sized pools.