Distribution of Iospilidae (Annelida) along the eastern Brazilian coast (from Bahia to Rio de Janeiro)

We present the spatial distribution and abundance of the holoplanktonic family Iospilidae (Annelida, Polychaeta), along part of the eastern Brazilian coast, and its relation to environmental variables in the region. Samples were obtained from two collections made in 1998 and 2000 between 13°-25°S, and 28°- 42°W, on the Brazilian coast, between the Bay of Todos os Santos (BA) to Cape São Tomé (RJ). 216 stations were selected, covering the continental shelf, slope and oceanic regions, where plankton samples were collected for water and nutrient analysis. We analyzed environmental variables: temperature, salinity, dissolved oxygen, pH, ammonia, nitrite, nitrate, phosphate, silicate and chlorophyll-a. 363 individuals were collected, identifying two species, viz., Phalacrophorus uniformis and Phalacrophorus pictus, the first being the most abundant, with 354 individuals, while only nine specimens of P. pictus were found. Both species are mainly distributed in the oceanic region stations. The distribution of P. uniformis was related to the concentration of phosphate and nitrate. Significant differences between samples and between sectors of the continental shelf and oceanic region were found.