Distribution of pelagic ostracods (Halocyprididae) in the western part of Bransfield Strait, Antarctica. I. E. Drapun. The quantitative distribution of pelagic ostracods (Halocyprididae) in the western part of Bransfield Strait was analyzed based on zooplankton samples collected during the 7th Ukrainian Antarctic Expedition in March 2002. The maximum sampled depth varied from 200 to 1000 m. Eight species of halocyprids were recorded. Three of them were dominant in the whole sampled layer: Metaconchoecia isoheira (44 and 31 % accordingly in the layers 0 – 500 and deeper than 500 m), Alacia belgicae (28 and 23 %) and Alacia hettacra (24 and 21 %); the fourth one – Boroecia antipoda (21 %) – deeper than 500 m. The rest of species (Metaconchoecia skogsbergi, Proceroecia brachiaskos, Discoconchoecia aff. elegans and Conchoecissa symmetrica) were found not numerous in the deepest sampled layers (200 – 500, 500 – 1000 м). Most abundance and biomass of halocyprids (> 1000 ind./1000 m3 and up to 500 - 780 мг/1000 м3) was recorded in the 200 - 500 and deeper than 500 m layers. In the 0 – 100 m surface layer they were not numerous, the higher densities of ostracods was marked along the frontal zone formed due to mixture of waters of the Bellingshausen and Weddell seas.