Algae blamed for fish deaths while opposition call on government to step up

THE Department of Fisheries have confirmed a bloom of microscopic algae likely caused recent fish deaths in Cockburn Sound.

Supervising scientist Michael Snow said exhaustive testing had isolated a spike of a group of algal diatom species Chaetoceros spp. which have spines made of silica and are known to cause gill irritation in fish that can lead to mucous accumulation and respiratory failure.

“Similar diatoms have been implicated in fish death events in other parts of Australia and also internationally,” Dr Snow said.

“This bloom may also have been associated with low dissolved oxygen conditions which are known to periodically occur in (the) southern section of Cockburn Sound, placing extra stress on the fish.

“We know from experience that fish death events often involve multiple contributory factors that make cases difficult to solve.”

Dr Snow said the patience of the community was “appreciated” while the investigation was undertaken and other potential causes were eliminated.

“We cannot afford to jump to conclusions in these cases which must be based on solid scientific evidence,” he said.

“Investigations have included screening for a wide range of over 120 algal toxins and industrial contaminants including heavy metals, fertilisers, pesticides and hydrocarbons.

“Other Government agencies have also pursued and eliminated a number of other possibilities.”

Results received late yesterday – and confirmed earlier today – indicated the algal diatom was the most likely cause.

Dr Snow said satellite data also showed an increase in surface water temperature at the same time, which may have contributed to the bloom event.

“The diatom is 10-50 microns in size, which is similar to the diameter of a human hair,” he said.

“Diatoms naturally occur in all marine and estuarine environments. They are not harmful to humans. The Department of Health has confirmed the Sound is safe for fishing and swimming.”

The Department of Fisheries will continue to monitor fish stocks to assess the long-term implications of the fish deaths event.

A public report on the findings would be released at a later date, Dr Snow said.

This morning, Rockingham MLA Mark McGowan accused the State Government of being “all at sea” over its response and handling of event.

Mr McGowan and opposition fisheries and water spokesman David Kelly were at Palm Beach, Rockingham this morning where they called on the Barnett Government to deliver “real leadership” on the issue.

About 700 dead fish washed ashore at Careening Bay on Garden Island more than two weeks ago, while a large number of blowfish washed up on beaches around the Sound last week.

“The Government has not been proactive in dealing with the situation we’re confronting and have not been on top of what’s happened,” Mr McGowan said.

“I haven’t seen a minister down here or any proper communication with the community. I don’t think there’s been enough effort put into what’s going on. We deserve better answers.”

Both Mr McGowan and Mr Kelly were critical of Fisheries Minister Ken Baston, who on Friday said it was unsafe to swim and eat fish caught in the Sound, which contradicted the advice sent out by his department.

“The Government has the resources, we’re calling on them to throw every resource at the problem,” Mr McGowan said.

“When (Labor) were in government we had the Cockburn Sound Management Council, with a dedicated office locally and an ongoing monitoring program; that’s gone now. Our record is clear, the Government are the ones who are there right now and should have been on top of this when it first arose.”

Mr Kelly said he believed the impact on Cockburn Sound had been “far greater” than had been revealed.

“I’ve heard from various dive operators that large parts of the Sound are dead,” he said.

“The extent of the problem is much greater than the Government has led on. They’ve been slow to get on to the issues, played down the extent of the problem and don’t have a plan going forward.

“What is their plan to restore the Sound to its former condition? We shouldn’t be leaving it to members of the public to raise the alarm.”

The Courier has contacted the Minister’s office for comment.