Abundância e relação peso comprimento das espécies de peixes coletadas no Rio Paraguaçu, na Comunidade de Geolândia, Cabaceiras do Paraguaçu, Bahia, Brasil

Abstract

The Paraguaçu river has been used for research on the ichthyofauna due to its rich diversity and the changes in its course, such as the construction of dams for water supply, which has caused environmental problems, causing the disappearance of fish species. This study aimed to know the composition of the ichthyofauna and the structure of the populations, through the relationship weight-length, the assemblies of fish in the region of Geolandia, Cabaceiras do Paraguaçu, Bahia, collaborating with the evaluation of fish stocks in the hydroelectric reservoir of Pedra do Cavalo. In the period between March 2019 and February 2020, ten collections were made. From the specimens sampled was carried out the taxonomic identification and biometrics of all individuals captured. From these data were made analysis of population structure and abundance with the help of Excel 2013 software. During the ten month collection period, 248 individuals were captured, divided into three orders, six families, seven genera and nine species. A greater abundance of native species was observed, highlighting the species Hoplias malabaricus, occurring in greater numbers and frequently in all months of collection. It was also possible to relate the abundance with the rainfall in the period, being observed greater relative abundance in the rainiest months and a lower abundance in the dry season. For the weight-length relationship it was possible to make the analysis of six species due to the sample number, where five of these species presented a negative allometry, with a condition factor consistent with this relationship, evidencing that these populations present young individuals, exhibiting strategies linked to advanced stages of ecological succession of a community, surviving in environments whose competition is high. The species Serrassalmus piraya presented a value close to isometry, showing that growth and weight are in their ideal. We concluded, therefore, that the study was important for the knowledge of the ichthyofauna of the dam region, highlighting the relative abundance of native species, presenting almost 80% of the species collected.