The dugong will be spared by four Australian aboriginal clans from their hunt for the next five years after negotiations with the Queensland government.

The agreement would cover several hundred kilometers of water from Burrum Heads to Curtis Island.

The dugong, or sea cow, which sometimes grows to 3 metres in length and over 400 kilogrammes in weight, subsists mainly on seagrass and occasionally on sea quirts that live on seagrass beds.

The dugong was a popular catch for its oil, but because of over harvesting, by 1910 the industry collapsed due to the shrinking population. The species population takes a long time to recover because of its very slow breeding rate and vulnerability to loss of seagrass habitat.

The Gooreng Gooreng, Gurang, Tanbelang Bunda and Bailai clans also agreed to cut their harvest of green turtles to only 20 yearly.

The dugong and green turtle, considered endangered species, had a spike in deaths after the floods earlier this year wiped out seagrass beds.

From January to August there were 649 turtle deaths, while for all of 2010, there were only 79. For the same period there were 96 dugongs washed up dead on Queensland's coastline, which was slightly higher than 2010's 79 dugongs.

Although the two sea creatures are protected species, the Native Title Act granted traditional hunters the right to hunt dugong and sea turtles.

"That's why we are seeing increased numbers of strandings and deaths of these animals this year, and anything we can do to stem the number of deaths is more than welcome," Queensland Environment Minister Vicky Darling said in a statement quoted by the Sydney Morning Herald.

The clans' agreement is also in response to a call made earlier this week by wildlife campaigner Bob Irban, who sought a moratorium on traditional hunting. With the self-imposed ban, the aboriginal clans could better manage their seafood resources and monitor the waters for illegal poachers, Darling said.

The dugong is also found in places from eastern Africa to Vanuatu, but the Australian population is the more significant based on long-term conservation perspective. Government estimates from 1994 placed the number of dugongs at only 1,700 between Dunk Island and Bundaberg and another 800 for the same year in Harvey Bay.

But a James Cook University study showed that the dugong population at eastern Cape York is relatively stable at 10,000.

The conservation group WWF said that aside from hunting, the two species are also at threat from bigger sources such as coastal development and boat strikes triggered by the rise in shipping activity linked to the mining boom.