Avaliação da atividade dos organismos marinhos perfurantes de madeira (Teredinidae - Mollusca; Limnoriidae - Crustacea), ao longo do Canal de Itajuru, Cabo Frio, Estado do Rio de Janeiro, Brasil

Abstract

The main purpose of the present study was to examine the distribution of boring marine organisms along an increasing gradient of salinity observed in Itajuru Inlet, RJ, Brazil. The inlet is the only connection between the hypersaline Araruama Lagoon and the sea. Cumulative and 2-month-imersion panels were immersed at 3 different stations during the 2-year-experiment (feb/86 to mar/88). Thirteen species of Teredinidae (Mollusca) and 1 species of Limnoriidae (Crustacea) were found. A decreasing number of species of Teredinidae towards the end of the inlet {higher salinity variation station) was observed. However, the same did not happen concerning the total number of individuals. Two hypothesis may possibly explain this result. Strons tide currenta occurins in the middle station could have disturbed the larval settlement and consequently, the number of individuals per panel in this station would be smaller than the observed in the more interna! one. Hish salinity variations in this inner station could also have eliminated the more senditive species (oviparous). Hence, it would possibly occur an increase in the number of individuals of the more tolerant species (larviparous). A possible seasonal variation in individuals per panel along the year was notice. presented the more infested panela. By this the number of Summer months time, we also registred the greatest number of foul ing organisms in the panels. These results led us to assert that biomass of foul ing organisms is not an effective barrier to the settlement of wood boring molluscs.