Each year, tens to hundreds of thousands of giant Australian cuttlefish assemble off the coast of Whyalla, in the upper Spencer Gulf, to breed – the only place globally where cuttlefish gather en masse.

In surveys dating back to 1998, populations ranged from a low of 13,500 in 2013 to a high of 247,000 in 2020. More than 63,000 were recorded in 2025.