THE Environment and Sustainable Development Directorate have explained they can’t explain why there was a major fish kill event in Gungahlin’s Yerrabi Pond.

Test samples analysed by experts in Sydney have ruled out a virus as the cause of a significant number of fish deaths in Yerrabi Pond over the past month, Dr Lisa Evans, Aquatic Ecologist from the Environment and Planning Directorate has confirmed today.

“Since late September the ACT Government has been undertaking a range of tests to establish why a significant number of fish were found dead in Yerrabi Pond,” Dr Evans said.

“A range of water samples were taken by the Environment Protection Authority to help determine the cause of the deaths, but all results returned with readings in the normal ranges.

“The ACT Government has also been working with experts from the University of Sydney to examine other possible causes of the deaths, as more dead fish were discovered in early October.

“Test results from the University of Sydney have ruled out a number of fish viruses, and it is believed that the cause could be linked to a short term dissolved oxygen shortage associated with nutrient runoff from a recent storm, warmer water temperatures and significant amounts of filamentous algae in the pond. Breeding stress at this time of year could also be a contributing factor in the deaths.

“This is the first time that a Murray Cod fish kill has been observed in Yerrabi Pond in the 14 years that the pond has been stocked with these fish,” Dr Evans said.

The recent fish deaths are a timely reminder to Canberra residents that fish diseases can be transferred by people dumping unwanted pet fish into our waterways and illegally moving fish between waterways.

Dissolved oxygen levels in the water have since returned to normal. Members of the public should notify Canberra Connect on 13 22 81 if they see any dead fish in or around any local waterways

[“Amaroo aerial” by Graeme Bartlett – Own work. Licensed under CC BY-SA 3.0 via Wikimedia Commons.]