Objectives, methods, and results of a two-year aerial survey for sperm whales
off the coast of Western Australia, 1963-65, are described. Data from commercial
whaling operations have been included where appropriate.
Sperm whales were found well off the west coast, but only in a narrow strip
along the continental slope off the south coast. On both coasts, the main direction
of movement was parallel to the coastline and towards Cape Leeuwin. Unexpectedly,
whales off the west coast were heading mainly southwards throughout the year.
Densities in the offshore area north of Perth were significantly higher than along
the continental slope in the same region but similar to those along the continental
slope from Perth to Cape Leeuwin. The situation was reversed on the south coast
with whales being found, in high densities, only along the continental slope. Off
the west coast, there were marked decreases in abundance in winter, with peaks in
spring-early summer and autumn; no change in direction of movement could be
related to the peaks. Average numbers calculated as present in the survey area at
one time were: west coast, c. 1000 whales; south coast, c. 200 whales. South coast
data indicate the passage of about 40 whales in one 24 hr period, very similar to
results from whaling company aerial spotter data off Albany.
The hypothesis of two separate populations of sperm whales off Western
Australia is discussed and thought to be unlikely.
A small amount of data on baleen whale sightings is recorded.
Aspects of the hydrology and plant ecology of two normally-closed estuaries in the Bremer Bay Region, on the south coast of Western Australia.
