Use of mangrove habitat for reproductive activity by the fish assemblage in the Guaratuba Bay, Brazil

The role played by a southwestern Atlantic mangrove in the breeding activit y of estuarine fishes was evaluated. This fish assemblage represented 85 % of the total catches of the experimental fishery surveyed between 1993 and 1997. To evaluate the maturation and spawning processes, qualitative (macro scopic stages of maturation) and quantitative (gonadosomatic index) attribu tes were considered which were combined in a reproductive activity index. F our types of occupation were found in the mangrove, according to the reprod uctive patterns presented by each species. It was estimated that the Guarat uba mangrove is used as a spawning site - either regularly or occasionally - by about 40 % of the species, that make up 41 % to 46 % of the total abun dance of this fish assemblage. However, besides the spawning species, the m angrove attracts other species at advanced stages of maturation. The use of mangrove habitat for reproductive activity by the species is 52 to 57 % of the total fish abundance. Spring and summer are the seasons most associate d with the maturation and spawning processes. Although most of the assembla ge is formed by species that do not permanently inhabit the system, the Gua ratuba mangrove is a significant site for the life cycle of estuarine and m arine species occupying this coastal region. (C) 2000 Ifremer/CNRS/IRD/Edit ions scientifiques et medicales SAS.