Environment

Unique Species of Australia: The Australian Snubfin Dolphin

The Australian Snubfin Dolphin is found off the coasts of northern Austrlia.

Description

Until 2005, the Australian snubfin dolphin was considered an isolated population of the Irrawaddy dolphin, but was later recognized to be a distinct species with unique characteristics. The snubfin dolphin is recognized by its robust rounded forehead and small snubby dorsal fins, which distinguish it from other species of dolphins within the same habitation range. Their mouths have 12-19 sharp pointed teeth on each side of both jaws. Snubfin dolphins are tri-colored with a white belly, light brown on the sides, and brownish on top. They have notched tail fins with a narrow bowl-shaped trailing edges, and large broad flippers with a smooth curved edge. Adults grow up to 9 feet in length and can weight up to 400 pounds, with females being larger than males.

Habitat and Range

The snubfin dolphin has been recorded in northern Australia, where they inhabit the estuarine, riverine, and coastal waters. In the south, they are recorded to inhabit the shallow waters of Port Alma and Keppel Bay, near Rock Hampton in Queensland. The range of the species is expected to extend through the Pacific Ocean in Australia up to Papua Guinea. Approximately 200 snubfin dolphins have been recorded in the Pacific Ocean to date.

Behavior

Snubfin dolphins are reserved creatures that live in pods of five members, although larger pods with as many as 15 members have been observed. When uninterrupted they usually make short dives and surface quietly at intervals of 30 to 60 seconds. Unlike other dolphin species, snubfin dolphins do not bow ride, but instead do partial jumps while tail clapping. Australian snubfin dolphins communicate by making unique sounds including high-pitched clicks, broadband snaps, and whistles. They normally communicate to warn each other of the presence of predators, search for a potential mate, on announce the presence of food.

Diet

The Australian snubfin dolphin is a cunning predator with a predominantly meat-based diet. It mainly feeds on a wide variety of fish, crustaceans, and cephalopods found near its habitat. The dolphins mainly forage for food in estuaries, mangrove forests, and coral reefs, and sometimes navigate the deep waters at night when there is sufficient prey. They are sometimes observed to spurt water from their mouth, a behavior synonymous with their foraging behavior.

Threats

The snubfin is classified as a nearly threatened species following their drastic decline in the coastal waters of Australia that they inhabit. Their preference in coastal waters renders them susceptible to human interference through habitat degradation, noise and water pollution, and incidental capture by the Shark Control Program. Presently, the snubfin's biggest threat is bycatch, which means they are trapped in shark nets designed to protect swimming areas and fishing nets set to capture salmon. Pollution in the higher food chain makes dolphins susceptible to many diseases, thus further declining their population.

The International Union for Conservation of Nature (IUCN) lists snubfin dolphins as vulnerable creatures, calling for conservation efforts of the species before they become critically endangered. Some conservation efforts have been undertaken in Australia through coastal development and habitat modification programs aimed at creating marine parks with the intent of protecting the species.

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