But over 22 years of observing the SharkBay dolphins, a pattern emerged, and "it seemed (the spongers) were going out of their way to hang out with other spongers, " Mann said.
The shark spent six months as the main attraction in California's Monterey Bay Aquarium after becoming the first of her species to survive more than a few weeks in captivity.
Shark and Clark Islands, located off the harbourside suburb of Darling Point and Rose Bay respectively, became dedicated recreational areas as early as the 1870s and are now great places to watch the boat traffic in Sydney Harbour.