Oceanic condition and zooplankton distribution/ abundance in Bransfield Strait during austral summer 1989/1990

To delineate zooplankton distribution and abundance in Bransfield Strait, in relation to hydrographic condition, a total of 29 sampling stations was occupied for the CTD casts and plankton towings in a systematic grid from December 29, 1989 to January 7, 1990. Comparisons of temperature and salinity distributions and T-S diagrams suggest that the cold and saline Weddell Sea water entered from the Antarctic Sound flows southwest along the Antarctic Peninsula coast, turns to the north at the east of Trinity Island, then joins the Bellingshausen Sea water (warm and less saline water) near the south of Deception Island, and meanders northeastward in the surface layer of the northern strait. Bellingshausen Sea water enters near Low Island, then, mainly flows toward Deception Island. A total of 39 taxa of zooplankton were identified from samples. Several species of copepoda were the most abundant (57.7%) in terms of number, and followed by salpa (27.7%), chaetognatha (6.7%), and euphausia (1.3%). However, noticeably, macrozooplankton salpa (Ihlea sp. and Salpa sp.) predominated over the entire Bransfield Strait occupying 20 stations, and showed the highest biomass in zooplankton community. The highest number of salpa was shown in the northeastern entrance of Bransfield Strait, but low numbers were found along the stations near the Antarctic Peninsula coast. Fish larvae and euphausia were rarely found in the entire strait