Identificação de potenciais agregações reprodutivas de recursos pesqueiros recifais no Baixo Sul da Bahia: subsídios para a conservação do ecossistema marinho

Abstract

Spawning aggregations are defined as a group of fish on the same species gather for the purpose of spawning, with significantly higher densities or numbers than those found in the area during the non-reproductive periods. Such aggregations are associated with specific fishing locations at specific times, so are quite predictable and thus very vulnerable to fishing. We aim to identify sites and periods of possible spawning aggregations of Seriola dumerili and Occyurus chrysurus through exploratory analysis of catch rates by artisanal fleet of Southern Bahia, aiming to provide technical and scientific subsidies for biodiversity conservation and management of marine fishing resources. For S. dumerili were analyzed capture data and fishing effort of 1,171 landings recorded between October / 1997 and May / 2000 and between March / 2005 and March / 2016, whose largest catches were recorded between April and June. For O. chrysurus, 2,176 landings data were analyzed recorded between September 1997 and November 1999 and between April 2005 and March 2016 were was identified potential spawning aggregation sites in 23 locations identified by extreme values, outliers and far outlier relative abundance, measured as CPUE. Fisheries on bathymetric limits of 50 to 60m and between 90 and 100m, showed unusually high and recurrent catch rates. Given its relevance for maintenance of viable fish stocks and for being key habitats for the life cycle of the species, aggregations sites should be treated as special management units, aimed to establish activities of management acts affecting local and / or aggregation periods. It should also be considered in the environmental licensing process of exploration activities and exploration of hydrocarbons. Aggregations identified in this study should be the subject of further studies to confirm the sites and periods of occurrence and validation of the reproductive nature of these aggregation from biological sampling and survey of traditional knowledge of fishermen on fisheries held in these aggregations and involvement of these users as key actors in the monitoring process and propose feasible management strategies and conservation.