The vertical and spatial distribution of Pleuragramma antarcticum and Nototheniops larseni in the Bransfield Strait was studied during the BIOANTAR 93 cruise performed from RV >Hespérides> in Antarctic summer 1992/93. A multiple plankton net (Bioness) and a Bongo net were used to collect samples at 75 stations and one 24 h station. A number of depth layers (400-200, 200-150, 150-100, 50-20, 20-0 m) were sampled depending on the station. The water temperature and salinity profiles were analyzed to determine the association of species with water masses. Our data showed that the abundance of both Pleuragramma antarcticum and Nototheniops larseni is related to temperature. Abundance values exceeding 5 larvae/103m3 were seldom found when the temperature was less than 0°C. The relationship between larvae abundance and salinity seems to be inverse, although this result might be biased by the geographical distribution of stations and of sampled layers. In a 24 h station placed between Gerlache and Bransfield Strait, the most abundant fish larvae was Pleuragramma antarcticum, which were mainly found between 100-50 m and in warm waters (> 0°C). The daily migration of larvae in the vertical did not appear to be controlled by the oscillation of the pycnocline.

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