Spatial distribution of juvenile fish species in nursery grounds of a tropical coastal area of the south-western Atlantic

Background. Assessing patterns in habitat utilization and changes in the composition of biont assemblages is a key tool for efficient ecosystem conservation planning and management. Nevertheless, habitat use patterns by juvenile fish still need more comprehension. Therefore, the presently reported study investigated relations between the type of nursery ground and the structure juvenile fish assemblages in a tropical coastal area of the south-western Atlantic. Materials and methods. From December 2009 to November 2010, we conducted monthly sampling of ichthyofauna in two habitat types (mangrove and sandy beach) used as nursery grounds by juvenile fish of the south-western Atlantic. Species richness and abundance were used to identify spatial and temporal patterns in the distribution of fish assemblages throughout habitats’ dynamics. Results. A total of 845 fishes representing 16 families and 34 species were found during the presently reported study: Albula vulpes (Linnaeus, 1758); Atherinella brasiliensis (Quoy et Gaimard, 1825); Strongylura marina (Walbaum, 1792); Tylosurus acus acus (Lacepède, 1803); Caranx crysos (Mitchill, 1815); Caranx latus Agassiz, 1831; Oligoplites saurus (Bloch et Schneider, 1801); Selene setapinnis (Mitchill, 1815); Selene vomer (Linnaeus, 1758); Centropomus parallelus Poey, 1860; Centropomus undecimalis (Bloch, 1792); Harengula clupeola (Cuvier, 1829); Opisthonema oglinum (Lesueur, 1818); Anchoa tricolor (Spix et Agassiz, 1829); Anchovia clupeoides (Swainson, 1839); Diapterus auratus Ranzani, 1842; Diapterus rhombeus (Cuvier, 1829); Eucinostomus argenteus Baird et Girard, 1855; Eucinostomus gula (Quoy et Gaimard, 1824); Eucinostomus melanopterus (Bleeker, 1863); Bathygobius soporator (Valenciennes, 1837); Conodon nobilis (Linnaeus, 1758); Haemulon plumierii (Lacepède, 1801); Haemulopsis corvinaeformis (Steindachner, 1868); Hemiramphus brasiliensis (Linnaeus, 1758); Lutjanus apodus (Walbaum, 1792); Lutjanus griseus (Linnaeus, 1758); Lutjanus jocu (Bloch et Schneider, 1801); Mugil brevirostris (Ribeiro, 1915); Mugil curema Valenciennes, 1836; Mugil curvidens Valenciennes, 1836; Paralichthys tropicus Ginsburg, 1933; Sphyraena barracuda (Edwards, 1771); Sphoeroides testudineus (Linnaeus, 1758). No significant differences in species richness and total abundance were found between habitats and seasons. Nevertheless, our analyses showed that distinct sets of species use these areas. Moreover, we identified a strong relation between the rainfall and the species turnover in both habitats studied. Conclusion. Diversity of nursery grounds in coastal areas not only increases fish diversity but also plays an important role in the sustaining fish stocks.