Aquatic vertebrates in estuaries

Sea turtles, frogs and other aquatic animals live in our estuaries and use them for food, rest and shelter.

A number of aquatic vertebrate species other than fish rely on New South Wales estuaries. For example:

  • well-established populations of green turtles live in Port Stephens and Sydney Harbour
  • endangered green and golden bell frogs have been found in the Shoalhaven area, such as adjacent to Meroo Lake
  • the vulnerable wallum froglet lives in swamp sclerophyll forests, sedgelands and heathland habitats associated with estuaries north of the Greater Sydney region
  • Australian fur-seals and long-nosed fur seals have re-established breeding colonies in New South Wales after many colonies were wiped out due to widespread hunting; growing populations live in Sydney Harbour, Port Kembla and Newcastle Harbour.

Occasional visitors

Green turtle (Chelonia mydas)As well as these residential species, other more occasional visitors use New South Wales estuaries to feed and shelter.

These include sea turtles such as loggerhead and leatherback turtles. Sea turtles are more likely to visit estuaries to graze on seagrass or rest, and are being found further south along the east coast of Australia because of increasing temperatures of water and sand. Sea turtle nesting events are becoming more frequent in northern NSW, and sea turtles have been sighted as far south as Jervis Bay.

Bottlenose dolphins are commonly seen in estuaries and breeding populations are known at Port Stephens, Jervis Bay and Twofold Bay.

If you’re lucky, you may even spot whales. Humpback and southern right whales visit estuaries such as Jervis Bay, Sydney Harbour and Botany Bay for short periods on their annual migrations up and down the coast.


Amphibians are particularly susceptible to chemical pollution and chytrid fungal infection as well as predation by domestic and feral cats and foxes.

The main estuarine threats to the larger marine mammals and sea turtles include boat strikes and entanglement in mooring lines and fishing gear.