f^L'S. CrOMP. 200U' B R E V I O'WM U.\JJVGRSiTY Rluseuni of Comparataye Zoology Cambridge, Mass. x^pril, 1972 Number 388 INTENSE LOW-FREQUENCY SOUNDS FROM AN ANTARCTIC MINKE WHALE, BALAENOPTERA ACUTOROSTRATA William E. Schevill and William A. Watkins Abstract. Intense low-freqnencv underwater sounds, somewhat similar to those heard from other species of Btihwitoptoa, have been recorded from ininke whales, Balaenoptera acuturostrata Lacepede 1804, in tlie Ross Sea, Antarctica. The small Balaenoptera f ininke whales) of the Antarctic had for many vears been identified as B. acutorostrata Lacepede I8U4, until \Villiamson 1959 and 1961 ) indicated that some of them might be referable to B. bonaerensis Burmeister 1867, which van Utrecht and \an dcr Spoel 1962) considered no more than a \ariety. Since our Ross Sea whales showed us only the top of the back and the part of the head from the blowholes forward . Fig. 1 ) , we could not judge whether they were this form or the t\pical acutorostrata, so we refrained from reporting the sounds till the relationship of these Antarctic minke whales to those in other parts of the world was more clearly defined. Ohsunii, Masaki, and Kawamura (1970) have now compared the southern and northern forms and concluded p. 116) that an\ differences were minor and that the Antarctic minke whale was not taxonomically separable from the typical northern Balaenoptera acutorostrata, and this conclusion we happily accept. Our recordings were made from the edge of the Ross ice shelf 2 km east of Cape Crozier, Ross Island, on 22 Noxember 1964. A whale had been sighted earlier in the 4-km stretch of open water between the ice shelf and the loo.se pack-ice further out, but it was too far away for identification. A light northerly wind e\entually clo.sed this open water and dro\e the pack-ice against the ice shelf. Large (hunks of ice were forced on edge,
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