Minke Whale Helicopter Surveys from McMurdo Station
Our objective was to describe the distribution, size, and behavior of the Ross Island segment of minke whale populations summering in the Ross Sea. Eight helicopter survey flights in 1981 were conducted over the icebreaker channel and its associated cracks and over the waters near the fast-ice edge (approximately 6 nautical miles to either side of the channel mouth). Five times, we landed on the ice and maintained ice-edge hydro phone- recording stations (a total of 4.25 hours of recordings).
From 36 to 64 minke whales were observed during each flight, as individuals and in pods of up to 38. Their distribution was clumped along the ice edge and in wide cracks. The whales also used areas under the ice extensively, capitalizing on small cracks and holes to penetrate under the fast ice to at least 2.5 nautical miles from the nearest appreciable open water. Several whales were seen respiring in holes so narrow they had to “spy-hop” to expose the blowhole above the water surface. Individual whales were observed to dive for up to 14 minutes. In observed feeding instances, whales were swimming on either side, and their throats were distended. Since the water near the whales was brownish-red, prey were assumed to be krill. We estimated the population of minke whales off western and northwestern Ross Island is between 65 and 130.