TECHNICAL REPORT OF THE SCALLOP PROJECT CRUISES. II. CRUISES II (March 15 to 17, 1996) and III (April 20 to 22, 1996)

Abstract

Main technical results and original data of the Scallop Project Cruises II (March 15 to 17, 1996) and III (April 20 to 22, 1996) are presented in this Report. The aims of the cruises were: a) to map in detail two beds located during Cruise I; b) to test structural modifications performed in the sampling equipment (beam-trawl) and; c) to estimate its catch efficiency by scuba diving. Profiles of salinity and temperature of water column vvere obtained in the center of the beds. In march, temperature showed a strong vertical gradient in the southernmost area (São Francisco do Sul bed). This pattern changed in April, with temperature and salinity values more constant along the water column, although some stratification could yet be observed in the northernmost bed (Bom Abrigo bed). Besides their low abundances, scallops showed a narrow bathymetrical and latitudinal distribulon in both areas. Chione pubera, a very abundant venerid bivalve found during Cruise 1, attained its highest densities in shallower stations of the Bom Abrigo region. Structural modifications performed in the equipment were responsible either by the lowering (Cruise II) or the improvement (Cruise III) of yields. However, diving operations confirmed the low densities of scallops, with no individual found along either the 90 (Cruise II) or 180 m2 (Cruise III) researcfied areas.