Whales and dolphins

Whales and dolphins are commonly known by their scientific name: cetaceans. Cetaceans are warm blooded mammals that spend their entire life in the water. After several years they reach sexual maturity and deliver live young every two to three years. They are also defined by the use of a blowhole on the top of their head for breathing and their long life spans.

Moreton Bay Marine Park has the highest recorded diversity and abundance of resident and transient cetaceans in Australia ¹. Humpback whales visit Moreton Bay Marine Park when migrating to and from their southern feeding grounds between June and October. Eight species of dolphin have also been recorded in the marine park including two resident species; the bottlenose and the Australian Humpback dolphin. Throughout the year other species are also known to visit the marine park including: killer whales, southern right whales, sperm whales, melon-headed whales, minke whales, common dolphins, spinner dolphins and Risso's dolphins.

Whales in the marine park

Humpback whales are regular visitors to Moreton Bay Marine Park and are amazing to watch. Their acrobatic displays such as leaping, rolling and breaching provide breathtaking viewing for whale watchers. Every winter and spring they travel via Moreton Bay on their annual migration between their feeding grounds in the Southern Ocean and their breeding and calving areas in northern tropical waters.

Humpback whales (Megaptera novaeangliae)

• The humpback whale is listed under the Environment Protection and Biodiversity Conservation Act 1999 and by the World Conservation Union (IUCN) as vulnerable (facing high risk of extinction in the wild in the medium-term future). ²
• The east Australian population is recovering from the large-scale, industrialised whaling activities that occurred between 1949 and 1962. The most recent survey estimated the population at 30,000 animals, with an annual increase of 11 percent. ³
• Migaloo, the only known white humpback whale in the world also travels via Moreton Bay.
• The humpback whale is also well known for its 'songs' particularly during breeding.

Dolphins in the marine park

Brisbane is unique among the major cities of Australia in having an abundance of dolphins in local waters. Its resident species include:

Bottlenose (Tursiops aduncus)

• There are two populations of bottlenose dolphins in Moreton Bay which are distinguished as

  - 'Non-trawler dolphins': found in shallow water, close to shore over seagrass; and
  - 'Trawler dolphins': found in deep water, farther from shore where trawlers operate. ⁴

• Moreton Bay has the largest resident population of bottlenose dolphins in the world.

Australian humpback dolphin (Sousa sahulensis)

• They are listed as vulnerable under Queensland's Nature Conservation Act 1992.
• Moreton Bay is the only place where they have been recorded several kilometres from shore. ⁵
• Moreton Bay is also the southern most limit for a population on the east coast. ⁶
• They are very reliant on the estuaries and the western part of Moreton Bay, with sightings in Brisbane River. They are therefore susceptible to impacts from coastal development and agriculture.
• Because of their inshore habitat they are particularly susceptible to intake of pollutants. ⁶
• The only available information on numbers of Australian humpback dolphins (not actual population estimates) sighted during aerial surveys, suggests the population is probably declining.⁷

Pressures

Whales and dolphins are subject to a wide variety of impacts, with different species being subject to different pressures. Living so close to a growing human population places our resident dolphins and migrating humpback whales under serious threat. Entanglement in nets, vessel strikes, habitat loss, unpermitted feeding, pollution and harassment are some of the major threats facing whales and dolphins.

Protection

Continuing research and changes in public attitudes has lead to legislation changes in the protection of Australia's cetaceans. All cetaceans are protected under state and Commonwealth legislation. The Environment Protection and Biodiversity Conservation Act 1999 establishes the Australian Whale Sanctuary and gives high level protection to whales and dolphins within Australian waters. ⁸

Under Commonwealth Law, whaling within 200 miles of Australia's coastline is banned. State and territory governments are responsible for conservation and protection of whales in coastal waters (out to the three nautical mile limit). This includes responding to stranded and entangled whales and managing whale watching activities. ⁹

More information

Further reading

1 Chilvers, B.L. et al (2005) An example of the co-existance of significant marine mammal populations and large-scale coastal development, Moreton Bay, Queensland

2 IUCN (2007) 2006 IUCN Red List of Threatened Species: Cetacean Specialist Group 1996. Megaptera novaeangliae. International Union for Conservation of Nature, viewed 20 February 2007

3 GBRMPA (2007) Whales and Dolphins, Great Barrier Reef Marine Park Authority, Townsville, viewed 18 February 2007

4 DEH (2004) Bottlenose Dolphins in Australia: current knowledge and future research, Department of Environment and Heritage, Canberra

5 Cokeron, P.J. (1990) Aspects of the behavioural ecology of inshore dolphins, Tursiops truncatus and Sousa chinensis in Moreton Bay, Australia

6 Hale, P. and Lamb, D. eds. (1997) Conservation outside of nature reserves, University of Queensland, Brisbane

7 GBRMPA (2007) Whales and dolphins, Great Barrier Reef Marine Park Authority, Townsville, viewed 18 February 2007

8 Whale protection, Department of Sustainability, Environment, Water, Population and Communities.

9 Whales, dolphins and porpoises, Department of Sustainability, Environment, Water, Population and Communities.

Humpback whale breaching, Moreton Bay Marine Park.

Moreton Bay Marine Park has the highest recorded diversity and abundance of resident and transient cetaceans in Australia.