Dugongs Disappearing Worldwide Due to Human Overload

CARTAGENA, Colombia, February 13, 2002 (ENS) - The dugong, a marine species that is a key indicator of coastal health, is vanishing in the 37 countries and territories, environment ministers from around the world meeting here were told today. Where dugongs cannot thrive, coastal environments will soon fail to support people as well, the new report warns.

Results of the first global study of the dugong, also known as the sea cow, were presented at the seventh special session of the Governing Council of the United Nations Environment Programme (UNEP) and the Global Ministerial Environment Forum taking place in this northern seaside city.

The list of human threats to dugong survival is long - polluted runoff from the land, coastal developments, boat traffic and fishermens' nets, hunting for meat, amulets and trophies. Port developments and dredging are destroying dugong habitat and the seagrass beds on which they graze.


Dugongs in the clear waters of Western Australia (Photo courtesy Australia4all.com)
Climate change, bringing more violent, damaging storms and flash floods, poses a new threat. The report notes that such events have, in places like South East Asia and Australia, devastated hundreds of square miles of seagrass beds.

Helene Marsh, professor of environmental science at James Cook University in Townsville, Australia, and the lead author of the report, said, "Dugongs appear to have disappeared or already become extinct in some places such as the waters off Mauritius, the Seychelles, western Sri Lanka, the Maldives, Japan's Sakishima Shoto Islands, Hong Kong's Pearl River estuary, several islands in the Philippines including Zambales and Cebu, and parts of Cambodia and Vietnam."

"Elsewhere populations appear to be declining with the possible exception of northern Australian waters and those of the Red Sea area and Arabian Gulf. The situation in East Africa is particularly alarming, and it is possible that this will be the next place where the dugong becomes extinct unless urgent action is taken," Marsh said.

Her report has been funded by organizations including UNEP, the World Conservation Union (IUCN), and the CRC Reef Research Centre.

Robert Hepworth, deputy director of UNEP's Division of Environmental Conventions, said all countries must cooperate to prevent international commercial exploitation of this vulnerable species.

"Dugongs deserve the same attention already devoted to other marine mammals such as dolphins and small whales, where joint management plans could be implemented at national and regional level," said Hepworth. "The dugong's main diet of seagrass also occurs frequently alongside coral and mangrove ecosystems. Conservation programs already in place, such as the International Coral Reef Action Network, can be part of the effort to save dugongs."

In compiling the report, "The Dugong: Status Report and Action Plans for Countries and Territories in its Range," investigators gathered information from researchers, local people, fishermen and government officials in the 37 countries and territories where the animal has historically been found.

They learned that human populations are growing across much of the dugong's range, putting pressure on the coastal habitats where dugongs are restricted as a result of their dependence on seagrasses for food.

The report makes urgent conservation recommendations aimed at stemming the decline and raising dugong numbers centering around the protection of seagrass beds upon which these herbivorous animals' are dependent for food.


Dugong grazing on seagrass in Shark Bay, Western Australia (Photo courtesy Australia Rentals)
Seagrasses need sunlight to thrive. In many areas of the world, seagrass beds are being cleared for development or smothered by silt and mud as a result of runoff due to overgrazing, intensive agriculture and deforestation. Herbicides that are applied to sugar cane plantations wash off into the sea damaging seagrass beds.

There are some bright spots in the picture of dugong survival. The waters of Western Australia support many thousands of dugong which appear to be free from damaging levels of human activity in key areas like Shark Bay.

Australia's Northern Territory and Queensland coasts, and the Gulf of Carpentaria, also support thousands of dugongs. There is some hunting by indigenous peoples, and there is a risk of heavy metal pollution from port facilities, but Marsh reports that generally the animals do not appear under too much threat except along the urban east coast of Queensland.

The dugong population in the Arabian, or Persian, Gulf is believed to be the second largest in the world after Australia. Akab Island in the United Arab Emirates (UAE) is, at 6,000 years old, the oldest site where remains of the animals have been discovered.

Dugongs are concentrated along the coast of Saudi Arabia, Bahrain, Qatar and the UAE.

But in East Africa dugongs are "likely to become extinct," Marsh's team reports. The scientists say gill net fisheries, in which dugongs can become entangled, are a key concern.

Few if any dugongs now remain off the coasts of Somalia, Kenya, Tanzania, Mozambique, the Comoros, Madagascar, Seychelles and Mauritius, although the coastal waters of these countries once were inhabited by herds in the hundreds.

Herds of many hundreds once occurred in the Palk Strait between India and Sri Lanka but the most recent surveys have failed to find any.

The waters off Okinawa Island are now thought to be the only place in Japan where dugongs are left. The seagrass meadows which support them are being destroyed by land reclamation and the expansion of seaweed aquaculture operations.

In China, dugongs are now found only in and around Hainan Island. They are at risk from seagrass habitat destruction from fish and shrimp ponds, and rising sea levels which cause increased erosion and siltation from the land. Hainan is a popular tourist destination and dugongs may also be being disturbed and displaced by boats and Scuba divers.

Records of dugongs in Singapore waters date back to 1821, but they were considered largely extinct by the 1970s. They are declining in the Philippines and Thailand, and the report says there have been sightings of a few dugongs in Malaysian and Brunei waters.

The animals are scattered in small numbers throughout Indonesian waters. In the 1970s there were an estimated 10,000 dugongs in Indonesia. The latest estimate is 1,000.

Dugongs reproduce at a very low rate with females rarely producing more than one calf, and failing to reproduce at all when food is scarce.


UNEP chief Klaus Toepfer addresses ministerial delegates in Cartagena. (Photo courtesy ENB)
UNEP Executive Director Klaus Toepfer sees dugong survival as a key indictor of successful control of global warming and land based marine pollution. "There are many reasons for fighting climate change. Securing the future of the oceans is a crucial one," he said.

Late last year in Montreal, nations met and agreed to revitalize the Global Programme of Action for the Protection of the Marine Environment from Land-Based Activities. Toepfer said, "The health of dugong populations could become a key indicator in many parts of the globe as to whether this renewed initiative is succeeding."