Abstract


Aerial observations of humpback whales in the region of Point Cloates, Western Australia, during 1952 are recorded. The first southward-moving humpback whale was sighted on July 21, while decreasing numbers were seen moving northwards until early October. In 1952 the change from a predominantly northward migration of humpback whales to a southward migration occurred close to August 24. The speed of migration of a number of these whales is recorded, the mean value being 4.3 kt. A few humpback whale calves were sighted early in July and a peak in their occurrence in August suggests maximum frequency of parturition early in August. A very great increase in the occurrence of calves in the area late in the season suggests that female humpback whales rearing calves move southwards later than other individuals. Some evidence is presented that Exmouth Gulf is a nursery area.

The presence of some killer, fin, blue, and minke whales in the area is noted.