Seasonal cycles of the carcinofauna caught as bycatch in sea-bob shrimps fisheries on Santa Catarina`s Coast

Abstract

The sea bob-shrimp fisheries, is considered effective in catch the target specie, but has low selectivity because catch high amounts of bycatch in trawls. In this context, the present study aimed to characterize the catches of shrimp fishing over thirteen years in Santa Catarina coast and also search for seasonal patterns in environmental conditions and crustacean community on study area. The experimental hauls were deployed monthly in three fishing spots in the study area. Results were grouped according to the seasons and were applied multivariate statistical analyzes to achieved our goals. Discriminant Analysis (AD) showed a marked fluctuation in salinity and temperature among seasons. Crustacean community consisted of species with abundances and frequencies unequal and, apparently, environmental variations influenced formation of seasonal assemblages in the study area (ANOSIM, R = 0.247; p = 0.001). Analysis of the Similarity Percentage (SIMPER) showed that species that contributed most to the differences reported were: X. kroyeri, A. longinaris, P. muelleri and C. ornatus. Such variations resulted in statistical differences on proportion target specie/carcinofauna, as detected by the chi-square test (X2 = 311,911,243.01; GL = 6, p <0.000001).