Vasse fish deaths tests completed
Released 30 Apr 2013
Tests in response to the fish deaths in the lower Vasse estuary have been completed.
Estimates including information from the clean-up operation are that up to 10,000 fish died over a five day period in a number of nearby locations either side of the Vasse floodgates.
Fish pathology tests completed by the Department of Fisheries have shown the fish were suffering a reaction to materials toxic to fish, which were present in the water at the time of death.
"Water tests have shown that although there was a low amount of a potentially harmful dinoflagellate species Karlodinium detected, that there is no evidence to suggest it was the cause of the fish deaths at the time," Department of Water district manager Dr Kath Lynch said.
"The combination of water and fish pathology tests would indicate that the likely cause of the fish deaths was an adverse reaction to noxious substances and bacteria associated with the breakdown of high organic loads washed down the drains by the first winter rains.
"Low dissolved oxygen was found in initial water tests and although it appears not to be the direct cause of death, it is likely to have contributed."
"The department will continue to work with community and business representatives on solutions that will improve the quality of water entering the system via drains."
Works currently underway include improving fertiliser management in rural and urban areas, upgrading dairy effluent management, fencing waterways, and retrofitting urban stormwater.
People are asked to report any fish deaths by ringing the Department of Fisheries Fishwatch number on 1800 815 507.
Contact: Peter Collins
Phone: (08) 6364 6848 / 0434 603 441