Variações espaço-temporais da ictiofauna diurna e a influência de variáveis ambientais em sua distribuição foram estudadas na zona de arrebentação de três praias no Município de São Francisco do Itabapoana, costa norte do Rio de Janeiro. Entre agosto/1999 e agosto/2000 foram realizados mensalmente três arrastos com rede ''picaré'' e obtidos valores de variáveis ambientais em Barra do Itabapoana (21º17' S, 40º57' W), adjacente ao estuário do rio Itabapoana, Gargaú (21º37' S, 41º05' W), adjacente ao estuário do rio Paraíba do Sul, e Praia de Manguinhos (21º23' S, 41º01' W), intermediária. Um total de 4.652 peixes (74.155kg) foi capturado nas três praias, com predomínio de espécies estuarino-dependentes (44%), seguidas por espécies marinhas (31%), estuarinas (19%) e dulcícolas (6%). Valores de riqueza de espécies de peixes, número de indivíduos e peso úmido diferiram significativamente entre as praias, sendo superiores em Gargaú, seguida por Manguinhos e Barra do Itabapoana, respectivamente. A análise de correspondência canônica confirmou a influência das vazões de ambos os rios, da salinidade e da abundância de material vegetal na distribuição e dinâmica da ictiofauna diurna da zona de arrebentação de São Francisco do Itabapoana.

Spatial and temporal variations of diurnal ichthyofauna and the environmental variables influences on its distribution were studied at the surf-zone of three beaches of São Francisco do Itabapoana, northern coast of Rio de Janeiro, Brazil. From August/1999 to August/2000, three beach seine hauls were made monthly, and environmental variables were recorded. A total number of 4,562 fishes (74,155g) were sampled at the three beaches, where estuarine-dependent species prevailed (44%), followed by marine (31%), estuarine (19%) and freshwater species (3%). Species richness, number of individuals and wet weight were significantly higher at Gargaú, followed by Manguinhos and Barra do Itabapoana, respectively. Canonical Correspondence Analysis highlighted influences of the rivers flushing, salinity and plant abundance on the diurnal ichthyofauna distribution and dynamics of São Francisco do Itabapoana surf-zone.

Artificial reefs have become an important and popular resource enhancement technique by concentrating fishes and by increasing natural production of biological resources. In order to increase the necto-benthic colonization potencial, an artificial reef was installed on the northern coast of Rio de Janeiro (21º27'S, 41ºOO'W), an area with typically low relief bottom. Measuring nearly 1500 m², the reef consisted of four sets of different materials randomly disposed: concrete pipes (N = 12); tires structures (N = 20); and cement tanks (N = 7) and pre-made blocks (N = 4). ln order to determine the artificial reef effects on the teleost community, trammel nets were used for monthly sampling the reef site (RA) and on a control area (AC) with sandy bottom. During the 23-month survey from April/96 to March/98, were recorded: a) Chaetodipterus faber (Broussonet, 1782) and Haemulon aurolieatum (Cuvier, 1829) as exclusive species of the RA; b) higher values of species richness and abundance on the RA, at least in 5 of 8 periods; c) increase on the fish abundance on summer months. Correlation analysis indicated that salinity and precipitation were the most significant environmental factors correlated with the temporal fish community variation. This results highlight the importance of rainfall periodicity and the influence of Paraíba do Sul River on the nekton assemblage distribution. It is suggested that the functional role of the artificial reef might be related to higher availability of local shelter and food resources.

Artificial reefs have been used in many countries to increase coastal fishery productivity. In order to increase fish attraction to the Northern Coast of Rio de Janeiro State, it was installed an artificial reef (1,500 m²) 5 nautical miles off Manguinhos's Bay (São Francisco de ltabapoana, Rio de Janeiro). The artificial structures were made of tires, concrete and cement blocks. A gill net of 125 x 3 m was monthly used in the artificial reef (AR) and in a control area (CA) to determine the effect of the experimental structures on the stock and diversity of coastal sharks. Considering the complexity of a sustainable elasmobranch exploitation, sharks were focused in this study. During 24 months of investigation (April/96 to March/98), a total of 325 individuais distributed in four shark species were captured in the two areas (AR and CA): Mustelus higmani (Springer & Lowe, 1963) (AR = 70; CA = 82 individuals), Rhizoprionodon lalandii (Valenciennes, 1839) (AR = 86; CA = 56 individuals), R. porosus (Poey, 1861) (AR = 16; CA = 14 individuals) and Carcharhinus brachyurus (Günther, 1870) (AR = 1 individual). The attractive potential of the artificial reef is suggested by the predominance of the shark R. lalandii in the reef complex after the first year of monitoring, with the increase of the structures.