Spatiotemporal Variation in Fish Assemblage in a Coastal Lagoon without Direct Contact with the Sea (Southeastern Brazil)

Abstract

Abstract The Cabiunas Lagoon is a narrow water body that is perpendicular to the sea and isolated from it by a sandbank. Before 1991, the sandbank was sometimes opened for a few days by local residents, but at present seawater only enters by limited groundwater seepage or by overtopping the sea barrier in storms. In 1998 the Restinga de Jurubatiba National Park was established, including the Cabiu nas Lagoon. Studies on the structure and spatial distribution of the fish assemblage were performed between 1991 and 1994; we carried out one year (2001–2002) of monthly monitoring of the lagoon to identify spatiotemporal variations in the lagoon fish assemblage. The closed sandbank altered salinity content, and favoured oligohaline conditions and the increase of the aquatic macrophyte abundance, promoting freshwater species dominance and reduction of the marine dependent and some coastal lagoon resident species of fish adapted to paralic ecosystems. Two freshwater, two coastal lagoon resident, and five marine d...