Algal bloom most liklely cause of NSW South Coast fish deaths

Test results have so far revealed that a microalgal bloom in the Carama Creek area is the most likely cause of death for thousands of fish which washed up on the NSW South Coast earlier this month. Residents reported dead and dying fish at a number of locations along Jervis Bay, including Honeymoon Bay, Hare Bay and Callala Bay in early January. No dead fish have been reported in the area since January 14.

Industry & Investment NSW Manager (Fisheries Ecosystems) Sarah Fairfull said sampling undertaken by I&I NSW, working in conjunction with the Department of Environment, Climate Change and Water and the Marine Parks Authority has shown a natural biological cause is most likely, rather than a chemical one.

“The agencies are awaiting results of further microalgae DNA analysis to positively identify this species and to determine the likelihood of it being a potential cause of the fish kill,” Ms Fairfull said. “These results are due later this week". “The agencies involved are working as fast as possible to obtain and release all test results".

“So far, all testing has indicated normal levels of nutrients and heavy metals in the water and sediments sampled in the affected area. No pesticides or ecotoxins were present in the water samples.” Harmful algae species do occur naturally in estuarine and marine environments and can bloom if environmental conditions are right from time to time.

There is no link between the algae reported in the water samples and the macro green algae Microdictyon that has been reported in the bay previously. Fish species affected by the kill include a large range of fish species and size classes including flathead, whiting, mullet, luderick and catfish.

Any further fish kills should be reported to I&I NSW’s 24 hour hot line 1800 043 536.

This blog is written by Martin Little The Aquaculturists, published and supported by the International Aquafeed Magazine from Perendale Publishers.