|The migratory journey of the humpback whales is in some respects a continuing reproduction cycle, with a portion of female humpbacks heading north to give birth in the warm shallow waters of the Great Barrier Reef, as other newly pregnant females head south to the Antarctic feeding grounds to fatten up in expectation of giving birth in the following season; often crossing each others path midway.
The terrain travelled by the humpbacks on their long journey from Antartica to the Great Barrier Reef Lagoon is revealed in this image of the ocean floor between Antarctica, Australia and New Zealand. The Continental Shelf on the East Coast of Australia is a narrow shelf dropping down to a deep canyon along which the whales migrate. Whether the humpbacks can see this terrain using sound is not known, what is known is that they navigate the long route annually with unerring accuracy and precise timing.
ABOVE: The Great Barrier Reef Lagoon and Fraser Island at its southern end - the humpbacks northern destination - can be easily seen off the north East Coast of Australia.