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 activity 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 (macroscopic stages of maturation) and quantitative (gonadosomatic index) attributes were considered which were combined in a reproductive activity index. Four types of occupation were found in the mangrove, according to the reproductive patterns presented by each species. It was estimated that the Guaratuba 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 abundance of this fish assemblage. However, besides the spawning species, the mangrove 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 associated with the maturation and spawning processes. Although most of the assemblage is formed by species that do not permanently inhabit the system, the Guaratuba mangrove is a significant site for the life cycle of estuarine and marine species occupying this coastal region. (C) 2000 Ifremer/CNRS/IRD/Editions scientifiques et medicales SAS.