Dolphins

Dolphins (and whales) are also known by their scientific name: cetaceans. Cetaceans are warm blooded mammals that spend their entire life in the water. They are characterised by the use of a blowhole on the top of their head for breathing and their long life spans.

Moreton Bay Marine Park is renowned for its high diversity and abundance of cetaceans, hosting both resident and transient species of dolphins, making it one of the most significant marine habitats in Australia. ¹

Brisbane is unique among Australia's major cities for its proximity to an abundance of dolphins in local waters. Moreton Bay Marine Park is home to two resident dolphin species, the Indo-Pacific bottlenose dolphin (Tursiops aduncus) and the Australian humpback dolphin (Sousa sahulensis), which are seen year-round. In addition, eight other dolphin species have been recorded in the park, including common dolphins (Delphinus delphis), spinner dolphins (Stenella longirostris), Risso’s dolphins (Grampus griseus) and melon-headed whales (Peponocephala electra) that belong to the dolphin family despite their name. Killer whales (Orcinus orca) – also a type of dolphin - are occasional visitors to the region.

Globally, dolphins face challenges from habitat degradation, pollution, boat traffic, and climate change. Entanglement in nets, vessel strikes and disturbance by people are some of the threats facing dolphins in Moreton Bay Marine Park. Conservation efforts in the marine park and public awareness campaigns, aim to protect the vital ecosystems and marine life in Moreton Bay, ensuring the marine park remains a haven for dolphins and a key area for research and observation.

Dolphins in the marine park

Indo-Pacific Bottlenose Dolphin (Tursiops aduncus)

Bottlenose dolphins are the largest of the beaked dolphins, with a short, stout beak marked by a crease at the forehead. They grow to an average length of about 3 metres and can live up to 45 years. These dolphins feed on a variety of prey, including invertebrates, bottom-dwelling fish, squid, and pelagic fish species. In Moreton Bay, they typically form small groups of about 15 individuals in bays, while offshore groups can number in the hundreds. A single calf is born after a gestation period of about a year. Remarkably, Moreton Bay is believed to host one of the largest resident populations of bottlenose dolphins globally, making it a critical area for their conservation.

Australian Humpback Dolphin (Sousa sahulensis)

The Australian humpback dolphin is a coastal species found in tropical and subtropical waters. These dolphins grow to about 2.7 metres in length and have a long, cylindrical beak. Their body colour ranges from white to pinkish-grey, with some individuals heavily spotted. They feed in shallow waters on fish, molluscs, and crustaceans, relying heavily on estuaries and the western part of Moreton Bay for their habitat. Sightings have also been recorded in the Brisbane River.²

Listed as vulnerable under Queensland's Nature Conservation Act 1992 and under the Environment Protection and Biodiversity Conservation Act 1999, Australian humpback dolphins face significant threats due to their inshore habitat preferences. They are particularly susceptible to pollutants from coastal development, agriculture, and urban runoff, which can accumulate in their prey and impact their health. Habitat degradation, including the loss of seagrass beds and mangroves, poses additional risks. Moreton Bay’s population of Australian humpback dolphins has been estimated at 128 individuals. ³

Protection

Both state and Commonwealth legislation contribute to the protection of dolphins.

At the state level, the Nature Conservation Act 1992 and the Marine Parks Act 2004 provide the legal framework for safeguarding marine mammals and their habitats.

The state government plays a critical role in the protection of dolphins and is responsible for managing cetacean conservation within coastal waters. This includes responding to stranded or entangled whales and dolphins, regulating whale-watching and dolphin feeding activities, and enforcing marine park zoning regulations. The Queensland Parks and Wildlife Service (QPWS) leads these efforts, and works closely with First Nations groups, local communities, researchers, and other stakeholders to ensure the effective management of cetacean populations.

These state laws align with the Commonwealth’s Environment Protection and Biodiversity Conservation Act 1999 (EPBC Act), which establishes the Australian Whale Sanctuary and offers high-level protection to cetaceans, including dolphins and whales, within Commonwealth waters.

Read more about watching marine mammals.

References and further reading

1. Chilvers, B.L., Lawler, I.R., Macknight, F., Marsh, H., Noad, M. and Paterson, R. 2005. Moreton Bay, Queensland, Australia: an example of the co-existence of significant marine mammal populations and large-scale coastal development. Biological Conservation, 122, 559-571.
2. Hawkins, E.R., Pogson-Manning, L., Jaehnichen, C. and Meager, J.J. (2019). Social dynamics and sexual segregation of Australian humpback dolphins (Sousa sahulensis) in Moreton Bay, Queensland. Marine Mammal Science, 1-22.
3. Meager, J. J., and Hawkins, E. (2017). Moreton Bay Dolphin Project: Long-Term Monitoring of Iconic Tropical Dolphins at a Key Index Site. Report prepared for the Department of the Environment and Energy, 79 pp. James Cook University. https://www.dolphinresearchaustralia.org/research/moreton-bay-dolphin-project/

Hawkins, E. R., Parra, G. J., & Cagnazzi, D. (2014). Humpback Dolphins of Western Australia: A Review of Current Knowledge and Recommendations for Future Management. In Advances in Marine Biology, 73, 1–40.

Parra, G. J., & Jefferson, T. A. (2025). Indo-Pacific and Australian humpback dolphins Sousa chinensis (Osbeck, 1765) and S. sahulensis Jefferson and Rosenbaum, 2014. In T. A. Jefferson (Ed.), Ridgway and Harrison's Handbook of Marine Mammals, Volume 1: Coastal Dolphins and Porpoises (pp. 75–108). Elsevier.