CLUSTERING AND AGGREGATIONS OF MINKE WHALES IN THE ANTARCTIC FEEDING GROUNDS

Information on the degree of clustering and aggregation behavior of wh ales is extremely limited. To obtain such information within various s urvey areas would not only be of help in understanding cetacean ecolog y, but also in optimizing the survey design in order to obtain abundan ce estimates with minimal variance. The clustering and aggregation pat terns of minke whales Balaenoptera acutorostrata were examined using t he data derived from systematic sighting surveys in 3 major feeding gr ounds in Antarctic waters. Distribution patterns showed that minke wha les clustered in the Antarctic feeding grounds but were relatively ran domly distributed within the aggregations, with the possibility that s chools within the aggregation tend to avoid each other. Higher cluster ing was observed in areas within bays (Ross Sea and Prydz Bay) than in areas of open water (Weddell Sea). Mean school sizes were positively correlated with density. Aggregation patterns in relation to density a nd abundance in Antarctic waters are presented.