Minke whales are seen outside the Antarctic in summer (Kasamatsu and Miyashita 1983) but much of the summer data is ambiguous with respect to identification as B. acutorostrata or B. bonaerensis, such that it remains unclear whether significant numbers of B. bonaerensis occur outside the Antarctic in summer.
The winter distribution is less well known. There is a wintering area off Costinha, Brazil (7Â°S), where minke whales, almost exclusively B. bonaerensis, were the target of a whaling operation during 1964â85, with the peak abundance in October (da Rocha and Braga 1982, Holt, de la Mare and van Beek 1982). The recovery in this fishery of two whales marked in the Antarctic in Area II at 62Â° and 69Â°S (Buckland and Duff 1989) demonstrates that at least some individuals from the Brazilian population migrate to the Antarctic. Minke whales were also seen (and small numbers caught) off Durban, South Africa: the seasonal distribution was bimodal, with peaks in April/May and September/October, suggestive of migration past the area (Best 1982). There are occasional records from Peru (VanWaerebeek and Reyes 1994).
Japanese scouting vessel data indicated high abundance of minke whales (species ambiguous) in November between 10Â°â30Â°S in the central South Pacific and in much of the eastern and southern Indian Ocean from the tropics southwards to 50Â°S (Miyashita et al. 1995). The limited information available from low-latitude surveys from the 1987/88 season onwards, when the two minke whale species were reliably distinguished, indicates that most of the minke whales were B. bonaerensis (Nishiwaki et al. 1991), probably on route from (as yet unknown) low-latitude breeding grounds to the Antarctic. The lack of any known areas of high concentration in winter suggests that the breeding distribution is rather dispersed and largely offshore (Kasamatsu et al. 1995). The species identity of minke whales seen in Indonesian waters in November (Miyashita et al. 1995) is unclear.
At least some of the Antarctic minke whale population remains in the Antarctic in winter (Ensor 1989), but the proportion has not been quantified.