Diversidade das pescarias realizadas com rede de emalhar em um estuário tropical do nordeste do Brasil

The aim of the present research was to study the diversity of the ichthyofauna captured with the most commonly used gillnet in the state of Pernambuco. In total, 14 collections were made in the Santa Cruz Canal (CSC) between July 2013 and June 2014. The samples were collected using a 30 mm mesh gillnet. The captured fish were removed and separated in margin and center positions, as well as in the net’s vertical position (upper, middle, and lower). Concerning frequency of occurrence, the species were classified as common, accessory, or occasional. Alpha and beta diversity analyses were performed. In total, 19 species were captured, with Opisthonema oglinum and Anchovia clupeoides being the only constants. The estimated alpha diversities did not show significant differences in the temporal and spatial strata. In the beta diversity, two groups were distinguished, with the largest generally occurring in large abundances of O. oglinum. The evaluated net was efficient for the target specie O. oglinum, while the catches of other species corresponded to less than 13% of the icitiofauna already found in the CSC. Therefore, management measures that aim to restrict the use of fishing gear for the protection of diversity considering the seasonality and spatiality in the channel is not recommended.