Fish deaths trigger estuary watch

Upgrades to water monitoring equipment to help prevent fish deaths at the Vasse-Wonnerup estuary are to be installed in the next two weeks.

As the Times went to press yesterday, Water Minister Mia Davies was set to announce the arrival of new data loggers to provide earlier detection of algal blooms and fish deaths.

“The monitoring is a central part of our fish kill mitigation strategy and response plans for this summer, ” Ms Davies said.

“The program was set up as a direct response to last April’s fish deaths and is an interagency initiative with the Vasse Estuary Technical Working Group.”

When low dissolved oxygen levels are detected in the Vasse-Wonnerup estuary, responses can be triggered, including opening the floodgates, opening the Wonnerup Inlet bar (if closed) and installing pumps to circulate water and improve dissolved oxygen levels.

Ms Davies said increased monitoring by the department since November showed the system was generally coping with summer conditions and reduced river flow.

“Weekly monitoring from upstream of the floodgates shows dissolved oxygen levels have fluctuated and declined during periods of hot weather, but remained above the level that triggers further actions, ” she said.

“The department and the Water Corporation opened up the Wonnerup Inlet sand bar before Christmas … the estuary on the sea side of the floodgates is mixing well and maintaining water quality.”

The Minister said the Vasse-Wonnerup and Geographe Bay catchment waterways received above-average rainfall last year.

“The upgraded monitoring equipment will help ensure a timely response if any fish deaths do look likely to occur, ” she said.

Wonnerup resident Jane Cummins, who runs an accommodation business in the area, welcomed the arrival of the new equipment but highlighted the urgency of preventing more fish deaths.

She said last weekend many small fish died due to the low water level of a pond adjacent to the Vasse River on her property.

“Last weekend the pond was full of birds feeding on dead fish and the smell was awful, ” Mrs Cummins said.

“I’ve given up calling the City because they just say to ring the water authority and nothing gets done.”