Locals and visitors to Marlo in the past week who have wondered down to the water may have seen a distressing sight as hundreds of dead fish have floated ashore.
James Costello, at the Marlo General Store, said the mass fish kill may have happened had the estuary not been reopened last week, but believes the flushing out of the fresh water with the opening contributed to the fish kill.
“The river was full of ash and debris from the fires,” Mr Costello said.
“Then when they opened the mouth the fresh water flushed out bringing all the ash and bits down and suffocating the fish.
“There were hundreds killed, all species. Whatever was in the river died.”
However Victorian Fisheries Authority chief executive officer, Travis Dowling, said opening the estuary decreased the chance of a much larger kill.
“We’ve been working with East Gippsland Catchment Management Authority (EGCMA) on cleaning up the fish and that is going very well. About one and a half tonne fish have been killed.
“Fish death was something that was going to happen anyway. Opening up the estuary last week mitigated a much larger fish kill occurring, as did the use of two waterwheels along the waterway in an attempt to break up the carbon and increase oxygen levels.
“There had been a lot of buildup of foliage and resultant carbon detracting from the oxygen level.”
“Estuary closures are created by a lack of flows in the rivers, in this case due to the drought we’ve been experiencing for three years,” EGCMA chief executive officer, Graeme Dear, said.
“When the authority artificially opens an estuary we monitor oxygen levels and fish condition. Oxygen levels in the Snowy estuary had been dropping, which meant that if we waited any longer to do an opening then we could have had a larger fish death.
“The work we did to open the Snowy estuary was to prevent a larger fish death occurring.”
Mr Dowling is confident the rivers and fish stock will recover well.
“What’s great about this area is that its river systems are otherwise very healthy,” he said.
He expects what has survived will see a strong replenishment of fish stocks.
“We’ll restock freshwater fish such as some estuary perch and bass. In the future we’ll stock dusty flathead too, but we need to work with New South Wales Authorities for that,” he said.
“Salt water species, such as black bream and luderick, we expect to replenish well naturally.”
Mr Dowling said fish kills similar to what has occurred in Marlo are not rare and that natural occurrences such as drought and algal blooms see similar results.
“What we’ve seen in similar situations is a strong recovery of fish stock, which is encouraging,” he said.
IMAGE: Around one and a half tonne of fish have been killed due to lack of oxygen in the Snowy River. (Photo: Marlo and Beyond images of Australia by Helmut Kummer)
