VIDEO: The giant Australian cuttlefish migration
IN THE WINTER of each year, along the coastline of a seaside mining town called Whyalla, thousands of Australian giant cuttlefish (Sepia apama) gather to mate, Jonathon Di Cecco explained.
“In the shallow, temperate waters a truly amazing technicoloured display can be witnessed by snorkelers and scuba divers alike. Cuttlefish flirtation, courtship, competition and mating unfolds among the rocks, algae and kelp.”
THE CUTTLEFISHES DECLINE
The number of giant cuttlefish that descend on South Australia’s Spencer Gulf to breed en masse is in worrying decline – the most recent estimate clocked a 93 per cent decrease.
DID YOU KNOW?
– Australian giant cuttlefish have blue blood, three hearts and a donut-shaped brain.
– The males can reach 1m in length and weigh up to 16kg; that’s about the size of a small dog.
– They can change colour, shape and texture to imitate things around them, such as rocks, sand or seaweed.
UNDERSTANDING THEIR DECLINE
In the late 1990s numbers of the world’s largest cuttlefish were first noticed gathering in their tens of thousands in a remote part of the gulf – the only place in the world where this is known to have occurred.
In 1999 there were an estimated 183,000, and their spectacular fights and breeding strategies captivated documentary makers, who came from all over the world to film these unusual creatures.
In 2013, however, estimates suggested there were only 13,500 cuttlefish at the breeding grounds, and it’s thought that the steepest decline took place over the last 3-4 years.
The reasons for the disappearance are largely unknown, and the theories range from a natural population boom-and-bust to industrial impacts.