Ecological diversity and distribution of Penaeoidea shrimps near islands with distinct environmental characteristics on the Northern Coast of São Paulo, Brazil

In this study, we analyzed the abundance and diversity (alpha, beta, assemblage composition, and indicator species) of marine shrimp near the Mar Virado and Couves Islands on the Northern Coast of São Paulo State, Brazil, over two years (1998–1999). We tested the hypothesis that the abundance and diversity of penaeoid shrimps are higher in areas adjacent to islands with a greater proportion of muddy sediments. The spatiotemporal associations of the Penaeoidea assemblage were examined in relation to environmental factors, including bottom temperature, salinity, organic matter, and sediment texture. A total of 1859 individuals were captured, representing three families and nine species. Mar Virado Island showed the highest shrimp abundance and diversity, a pattern associated with the predominance of fine sediments and higher temperatures. Xiphopenaeus spp., Penaeus schmitti, and Rimapenaeus constrictus were predominantly found near Mar Virado, whereas Penaeus paulensis and Penaeus brasiliensis were dominant near Couves Island. These findings highlight the critical role of island-specific sediment characteristics and water temperature in shaping shrimp distribution and diversity, with significant implications for fishery management and conservation strategies in these areas.