The in£uence of several environmental factors on the abundance and spatial^temporal distribution of the shrimp Artemesia longinaris were investigated from January 1998 to December 1999 in the Ubatuba region of Sa‹ o Paulo State, Brazil. Collections were performed monthly in the bays of Ubatumirim (UBM), Ubatuba (UBA) and Mar Virado (MV). Six sampling transects were established in each bay, four were parallel to the shore line, and two were next to the rocky shores. A commercial shrimp ¢shing boat equipped with two 'double-rig' nets was used. A total of 11,503 individuals was collected, including 1633 from UBM, 6344 from UBA and 3526 from MV. The majority of the captured specimens came from the deeper areas (15 to 20 m) with high salinity (34 to 36 ppt). The highest abundance of A. longinaris in Ubatuba bay was recorded in areas where ¢ne and very ¢ne sand comprised more than 70% of the sediment. Moreover, the abundance of A. longinaris followed a seasonal trend, being higher during the summer, when intrusions of cold South Atlantic Coastal Waters (SACW) are frequent. Thus, type of sediment, temperature and salinity are determinant factors in the distribution of A. longinaris in the studied region.

Paulo, BraziL Emailfransozo@ibb.IlI.U) Yp.br ABSTRACTThe influence of environmental factors on the abundance and spatial-tempotal distribution of the sltrimp Xiphopenaeus kroyeri was investigated. in southeastern Brazil over 2 years. Monthly collections were conducted in Mar Vrrado, Dbatuba and Dbatumi!im Bays using a commercial shrimp fishing boat equipped with 2 "doubJe.-rig" nets. Each bay was divided into 6 samplJng stations, all of which were less than 25 m deep. The spatial distribution of X kroyeri differed among Bays. Highest abundance values were recorded in areas where silt and clay comprised more than 70% of the bottom sediment Abundance of X kroyeri followed a seasonal trend, heing higher during fall and winter, when intrusions of tropical waters are frequent, causing an increase in salinity (> 35%") and temperature (> 21° C). A clear decrease in shrimp abundance followed a decrease in bottom temperature « 20" C) during spring and summer due to the influence of cold water currents, particularly the South Atlantic Central Water. These results suggest that sediment type, salinity, and temperature are among the most important variables affeclJng the spatial and seasonal distribution of this species.

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