Net sampling and continuous acoustic mea- surements within the Antarctic Polar Frontal Zone (APFZ) and in the vicinity of the Prince Edward Islands were conducted during austral autumn (April/May) 1997 to describe the composition and distribution of macrozooplankton and micronekton, and to investigate their relations to the prevailing oceanographic regime in the area. Two major circulation patterns associated with the Subantarctic (SAF) and Antarctic Polar (APF) Fronts existed in the oceanic environment surrounding the Prince Edward Islands, promoting high cross-frontal mixing both upstream and downstream of the islands. Average abundance and biomass of macroplankton/ micronekton in the top 300-m layer were 21 ind. 1000 m )3 and 467 mg DW 1000 m )3 , respectively. Pelagic crustaceans (euphausiids and amphipods), ﬁsh, chaetognaths and gelatinous zooplankton dominated numerically and by biomass. Continuous acoustic mea- surements displayed elevated pelagic biomass at the SAF and APF. Although four groupings of stations were identiﬁed using cluster analysis, a single macroplankton/ micronekton community was recognized in the top 300-m layer throughout the oshore area of the APFZ. A modiﬁcation of the APFZ community was observed within the inter-island region. Subantarctic species dominated zooplankton samples throughout the APFZ, although subtropical species were also well represented at stations occupied in the northern region of the APFZ. A biological response reﬂected in macroplankton com- munity composition, resulting from an extensive cross- frontal mixing, was observed within the APFZ around the Prince Edward Islands.
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