Marine Threat: Hundreds of dead fish reported in Queensland (January 7, 2010)
Queensland, Australia- GOLD Coast fishermen are being warned to stay away from a stretch of the Pimpama River until the cause of a mysterious fish kill can be solved. Hundreds of dead fish are floating in a section of the river on Kerkin Road near the weir but no one can explain what killed them. The Gold Coast City Council had no explanation for the kill, with a spokesman saying it could be acid sulphate soil run-off or oil spill from a boat. A Pimpama resident said it was clearly caused by sewerage spilling into the river from the Pimpama Recycled Water Treatment Plant. He said the fish had orange and blue colours on them and had been poisoned by substances being released by the plant. A council spokesman said any leftover recycled water was returned to the Seaway so there was no way it could have entered the river. Goldcoast.com.au's fishing expert Paul Burt said the kill could be as a result of run-off from the nearby sugar cane fields. He said the Coast's recent dry spell would have created a build up of chemicals being used on the cane and the recent rainfall would have caused those to run into the river. But Canegrowers chief executive Ian Ballantyne said this was not possible. "I can't image what chemicals would have been used in the past months to cause that," he said.
Mr Ballantyne said 85 per cent of fish kills occurred because of an excess of fresh water is the river system and over-oxygen of the water. Yesterday visitors to the river agreed, believing the fish had died because of too much fresh water from the rain. At least five people were fishing in the river, despite it being full of dead fish. "There's no worry with the water," said Melbourne tourist George Melas. "I've seen in happen in Melbourne when there's been a lot of rain. “We came here fishing for the first time and saw the disaster." Mr Burt said he recommended nobody fish or crab in a 1km radius of the area for a month or until a cause had been determined. Department of Environment and Resource Management, Regional Manager of Environmental Services, South East Region Andrew Connor said officers from the (DERM) and Gold Coast City Council attended the site of the fish kill on Wednesday, collecting water and fish samples for analysis. He said the Gold Coast City Council had confirmed it will remove the dead fish. "DERM is unable to determine the cause of the event until results from the samples collected are returned," he said. "It is anticipated this analysis may take up to two weeks. "Fish kills due to natural causes are not uncommon in rivers at the start of the wet season, when the first storms flush large amounts of plant matter (accumulated over the dry season) into waterways. "As this organic material is decomposed by bacteria and fungi, dissolved oxygen is consumed from the water. If oxygen levels fall low enough large numbers of fish may die through suffocation." -Gold Coast News