Analysis of sightings and catches of sperm whales (physeter catodon L.) in the cook strait area of New Zealand in 1963–4

Summary Sighting and catch data on sperm whales accumulated during a whale survey by the New Zealand Marine Department and whaling operations by the Tory Channel whaling company in 1963–4 were examined. The results showed a unimodal rise and fall in numbers of sperm whales in the Cook Strait region throughout the year. From a peak between December and April whale numbers declined steadily until November, when they rose again sharply. It is suggested from these results that the best choice for an eight‐month sperm whaling season would be one extending from November to July. It was concluded that the mean speed of sperm whales in the area was not likely to exceed 1 knot.