Stokes Inlet Fish Kill update
Released 26 Sep 2007
Scientific investigations of a fish kill in the Stokes Inlet near Esperance six weeks ago have eliminated metals, pesticides, insecticides and fungicides as likely causes.
The Department of Water's Chris Gunby said today that results from samples taken within the estuary on the 14th of August also indicated little evidence of algae as a major influence on the fish deaths.
"A possible cause is heavy rain and resultant freshwater inflow creating stratification, or a demarcation between fresh and salty water which reduces oxygen in the water," Mr Gunby said.
"Reports of dead fish in estuarine waters are occasionally received after significant rain, because fish can be caught unawares by freshwater.
"No further dead fish have been reported in Stokes Inlet, but the Department of Water will continue investigations into the fish kill event that occurred around the 14th August."
Mr Gunby said that as a precaution, the department was also examining possible effects of the herbicide atrazine that is widely used on crops for weed control (eg canola crops).
"A very low amount of atrazine was detected in the Inlet, and although it was below what would be considered harmful to fish, we are still testing for this as a process of elimination," Mr Gunby said.
"We have sent frozen fish flesh samples to a New south Wales laboratory but results are not expected for several weeks."
Mr Gunby said the public was encouraged to report any dead fish to the Department of Water on 9842 5760.
Contact: Peter Collins
Phone: (08) 6364 6848 / 0434 603 441