Pollution from farms and other human activities threatens the Great Barrier Reef, the world's largest living organism, says an Australian Government agency.
The coral reef, which attracts vivid tropical fish and thousands of tourists a year to view them, is being smothered, the Productivity Commission says in a report on the
health of the 2000km reef along the Queensland coast.
Fertiliser and pesticide use on sugar plantations, as well as land-clearing for cattle grazing, have increased chemical and sediment run-offs, says the commission, an advisory agency that reports on economic and social issues.
"Water quality in rivers entering the Great Barrier Reef lagoon has declined because of diffuse pollutants, especially sediments, nutrients and chemicals from cropping and grazing lands.
"This diffuse pollution threatens inshore reefs and associated ecosystems."
Probable effects from the pollution are reduced growth of coral, an inability to recover from hazards such as cyclones, coral being smothered by sediment, and unusually high growth rates for other organisms that overgrow coral or support its rivals.
The commission says it is hard to measure in detail the human effect on the reef, one of Australia's main tourism attractions, due to a lack of in-depth information, research and monitoring.
The findings back other reports in recent months that criticised the ecological impact on the reef from farming.
The sugar-cane industry, which is centred around the town of Mackay, has condemned such warnings as a witch-hunt and says tourism and urban pollution are just as much to blame.
Australia is one of the main exporters of sugar in the world, shipping A$1.4 billion ($1.5 billion) worth overseas in 2001/02.
The Productivity Commission also questions Government drought assistance packages that do not encourage cattle farmers to reduce herd numbers in dry periods.
Australia, with 100 million sheep and 27 million cattle, has gone through one of the worst droughts in a century. Recent rains have begun to break the "Big Dry" but have arrived too late for most crops.
- REUTERS
Herald Feature: Environment
