Vasse fish pathology tests completed
Released 07 Mar 2014
Pathology tests in response to the recent fish deaths near the Vasse floodgates and Wonnerup estuary have been completed.
Testing by the Department of Fisheries has shown the fish sampled had damage to the gills and bacterial infections at the time of death.
"Testing indicates the fish were suffering inflammatory changes to the gills which may have inhibited the uptake of oxygen and increased susceptibility to bacterial infection," Department of Water district manager Dr Kath Lynch said.
"Water samples taken at the time when the dead fish were found showed high levels of the algae Prymensium.
This species of algae has the potential to release toxins which can impact on gill function.
"Although dissolved oxygen levels in the water were within acceptable trigger levels, the impaired gill function certainly made it harder for the fish to breathe.
"This also significantly reduces the ability of the fish's immune system to fight bacterial infection."
Approximately 10,000 mullet are estimated to have died over three days between 3 to 5 February 2014.
"The Vasse Estuary Technical Working Group, which is made up of the City of Busselton, Water Corporation and the Departments of Fisheries, Water and Parks and Wildlife, responded quickly to this incident and followed the inter-agency fish kill mitigation and response plan," Dr Lynch said.
"Actions included opening the floodgates to allow any fish trapped in the affected area to move into the Wonnerup inlet and out to sea.
"The group will continue to monitor the area during this high risk period and continue to implement the response plan."
Contact with dead fish should be avoided and the Department of Health advises against eating or handling of fish found in these circumstances.
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