Swan River Trust searches for cause of fish deaths
MYSTERY:Swan River Trust is investigating the deaths of thousands of fish in the upper reaches of the river. Picture: Richard Hatherly Source: PerthNow
AUTHORITIES are investigating the deaths of thousands of fish in the Swan River.
River users reported finding about 5000 dead fish in the upper reaches of the river during the weekend.
Swan River Trust river systems manager Mark Cugley said officers were investigating the extent of the kill and what had caused it.
“The Trust was notified by the public on the weekend that a number of fish were seen floating in the water between Middle Swan bridge and the Ellen Brook confluence,” Mr Cugley said.
“Most of the fish appear to be juvenile black bream with the remainder being trumpeter.”
Mr Cugley said monitoring results had shown there were low oxygen levels in that part of the river due to high water temperatures creating conditions which were made worse by Friday’s storm.
“Sudden rainfall often drags nutrient rich organic matter into the river and this typically causes oxygen levels to rapidly drop below levels suitable for fish and other aquatic fauna,” he said.
“However, the exact cause of the deaths is yet to be determined and additional sampling will be carried out.
“We have two oxygenation plants providing refuge downstream and they have since been ramped up to full capacity.”
The Trust encourages the public to report dead or sluggish fish in the Swan Canning Riverpark on 9278 0900 or after hours on 0419 192 845.