Bathymetric distribution of the shrimp Rimapenaeus constrictus (Stimpson, 1874) (Decapoda, Penaeidae) in two locations off the southeastern Brazilian coast

The distribution of benthic organisms is directly or indirectly associated with the physical and chemical properties of the water and sediment. This study analysed the spatial and temporal distribution of Rimapenaeus constrictus in unconsolidated sublittoral sediments of two areas off the northern coast of the state of Sao Paulo, Brazil. We also analysed the association of environmental factors with the occurrence of this species. Shrimp were collected monthly from July 2001 to June 2003, with a fishing boat equipped with two double-rig nets, in the regions of Ubatuba (UBA) and Caraguatatuba (CA). The collections were made during the day, along five transects with mean depths of 5, 10, 15, 20, 25, 30, and 35 m. We obtained a total of 5478 individuals, 3403 (UBA = 2025 and CA = 1378) during the first year, and 2075 (UBA = 875 and CA = 1200) during the second year. Significant differences in abundance were observed in relation to depth, season of the year, and also in the interaction between region and depth. Higher abundances occurred in fall and winter, independently of the sampling year. The largest numbers of shrimp were caught on the 20-m transect in UBA and the 25-m transect in CA. It is concluded that the distribution pattern of this species is closely related to environmental factors, and the temperature of the bottom water and the sediment texture were the most significant variables affecting the distribution.

Scientific program of the Radioactive Ion Beams Facility in Brasil (RIBRAS)

The RIBRAS facility (Radioactive Ion Beams in Brasil) is installed in connection with the 8MV Pelletron tandem of the University of Sao Paulo Physics Institute. It consists of two superconducting solenoids which focalize light radioactive secondary beams of low energy, produced by transfer reactions. Recent experimental results include the elastic scattering and transfer reactions of (6)He halo nucleus on (9)Be, (27)Al, (51)V and (120)Sn targets. The elastic scattering and transfer of (8)Li and (7)Be on several targets is also being studied. The transfer reaction (8)Li(p,alpha)(5)He of astrophysical interest was also Studied in the E(cm)=0.2-2.5 MeV energy range.