We have travelled down to Jervis Bay on the south coast of New South Wales, about 200 kilometres south of Sydney and 25 kilometres southeast of Nowra to venture out of Jervis Bay into the Tasman Sea to look for humpback whales that migrate up the coastline beneath the weathered sandstone cliffs of the Beecroff Peninsula.
These spectacular sandstone cliffs that tower 100 metres vertically over the ocean helped the formation of the bay around 6000 years ago when the sea level finished rising. Before this time, during the ice age (20 – 15,000 years ago), the sea level was about 120 metres lower than today and the land extended 25 kilometres further eastward.
We saw five or six whales that surfaced many times to “blow” and then show their fluked tail which can lift above the surface in the dive sequences.
An Adult Humpback Whale grows to over 13.5 meters in length and weighs 30-40 tonnes, with the female whales growing larger than males on average. The Female Humpback Whale will calve about every 3 years, giving birth to a calf that is 2-3m in length and weighs over 300kg.
The mother produces over 500 litres of milk per day to help the calf gain 40-70 kg/day until weaning during the next year’s migration. The main reason these whales migrate is that the calves are born without the protective layer of blubber required to keep them warm in the near freezing waters of the Antarctic summer feeding grounds. An estimated 2500-5000 now migrate annually along the East Coast.