Distributional relationships are described for post-larval and larvalEuphausia superbaandThysanoessasp. (probablymacrura) and post-larvalEuphausia frigidacollected in 0–70/80 m and 0–175/200 m depth ranges with a MOCNESS sampler north of Elephant Island (61°S, 55°W) during 17–23 March 1984. LarvalE. superba(predominantly calyptopes stage 2 and 3) were rare shallower than 80 m at night. Day catches of post-larvalE. suberbawere small and night catches were primarily near the top of the thermocline above 50 m depth.Thysanoessasp. occurred throughout the 0–200 m depth range and was abundant in the upper 80 m both night and day.E. frigidamigrated to the upper 80 m at night from deeper day depths. Larval stages ofE. superbaand bost-larval stages of all three species demonstrated independent and variable vertical distribution patterns both night and day. Changes inE. superbaabundance and distributional patterns could to a certain extent be associated with observed environmental changes. An increase in larval and decrease in post-larvalE. superbaabundances between 0–80 m was associated with an intrusion of cold water at depth. At night, vertically restricted concentrations of post-larvalE. superbawere associated with shallow mixed layer depths, and a significant vertical separation of developmental stages and size categories was observed only during periods of stratification in the upper 80 m. Fluctuations in the distribution and abundance ofThysanoessasp. and distribution ofE. frigidadid not appear to be influenced by physical parameters within the upper 80 m. Within the 0–80 m depth range, the distributions of these two species differed from each other and fromE. superbaand showed large tow to tow variability that could not be related to physical parameters in the upper
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