Preliminary report on IWC-SO GLOBEC collaborative research in the western Antarctic Peninsula study area, March–June 2001

The first three cruises in the 'year round' Southern Ocean GLOBEC series for 2001-2002 were conducted from March - June 2001. International Whaling Commission researchers participated in all three cruises (Gould LMG 01-03 USA mooring cruise, Polarstern AntXVIII5b ship and helicopter based studies Germany, Nathaniel B Palmer NBP 01-03 USA survey cruise). A combination of ship, zodiac and helicopter based visual survey, tissue biopsy, and photo identification techniques were used on the vessels by the IWC. Passive acoustic moorings and expendable sonobuoys were deployed by the US passive acoustic team. The most frequently recorded and abundant baleen whale species in the study area were minke and humpback whales. An initial overview of oceanographic data shows strong patterns of correlation between autumn and early winter baleen whale distribution, the inshore cold Antarctic coastal current, and upwelling of this cold water produced by intrusions of the Antarctic Circumpolar Current into Marguerite Bay. Confirmation of krill autumn migration into inshore waters associated with complex bathymetry (ie. dense aggregations in deep pools or holes) was made on these surveys. This indicates that baleen whale prey is available throughout all seasons. Baleen whales were observed in Marguerite Bay as late as June, and it is likely that both humpback and minke whales overwinter in this region. These preliminary associations will be tested during the winter NB Palmer cruise (July - September) and through modelling and analysis planned between IWC and SO GLOBEC in 2001. The 2002 series of cruises will further test these and other physical and biological associations.