River fish kill probe
Wednesday, 19th December, 2018
By Emily McInerney
Lack of flows and the continuing drought have been blamed for the deaths of hundreds of fish along the Darling River over the weekend.
Yesterday a spokeswoman from the NSW Department of Primary Industries (DPI) said they investigated the issue and they found dead fish over a 40km stretch of the river.
“NSW District Fisheries Officer completed an investigation on Sunday,” she said.
“A significant number of fish were observed, which is estimated to be over 10,000 fish of various species.
“Initial reports were received of a few hundred Golden Perch from a single location adjacent to a landholder’s pump access.
“The subsequent investigation revealed fish mortalities along a 40km stretch of river, including numerous Murray Cod, Golden and Silver Perch.
“Native Bony Bream made up the majority of the dead fish.”
The DPI spokeswoman said the poor water quality is due to the prolonged dry period and algae blooms.
“The prolonged dry period has resulted in poor water quality along much of the Darling River.
“Algal alerts have been in place for several weeks in the Menindee region and linked to this, low dissolved oxygen levels are likely to occur within slow flowing or still sections of the river.
“The impact of, intense rainfall events after very hot conditions, similar to that experienced last week at Menindee can exacerbate water quality concerns by mixing remaining water in riverine pools and disrupting algal blooms, further reducing the oxygen available for already stressed fish.”
DPI reported that the water will continue to be monitored.
“WaterNSW continue to monitor water quality throughout the Menindee Lakes system and downstream into the Darling River.”
DPI Fisheries staff are undertaking further investigations into the fish deaths and encouraged members of the public to report any similar incidents or observations through the Fishers Watch hotline on 1800 043 536.
They advised anglers and residents along the Darling River that the current low flows and warming temperatures were likely to pose an ongoing threat to native fish throughout the summer.
WaterNSW Executive Manager System Operations, Adrian Langdon, said the lack of flows was heavily impacting on the situation.
“Water quality issues being experienced in the Menindee lakes system and Lower Darling are largely a result of enduring drought conditions and the impact on river flows and associated lake inflows,” Mr Langdon said.
“WaterNSW has increased the frequency of its local water testing regime, particularly at Copi Hollow, after a number of red alerts for blue green algae were issued for the lakes.
“With the Menindee lakes system falling to below five per cent of total capacity, WaterNSW will again contact local landholder representatives today to discuss future flow regimes and other options for extending supply and optimising water quality in water held in block banks.
“WaterNSW oversaw construction of four block banks at points along the Lower Darling to capture and supply up to four months of emergency supply once releases from weir 32 cease at the end of the year.
“The upper Darling River which feeds into the lakes has experienced extremely low-to-zero flow in the past 12 months, as have some of the major northern NSW river systems which feed into the Barwon-Darling.”
Recent heavy rainfall from Queensland/NSW will have little to no impact, according to Mr Langdon.
“While current Queensland storm activity is unlikely to generate flows into the upper reaches of the Barwon-Darling, the summer storm season is typically the best prospect of rain sufficient to generate such flows.”
NSW Water Minister Niall Blair said he was “quite concerned” with the fish kill that had occurred.
“DPI have reported that it was due to low flows and lack of oxygen in the water,” Minister Blair said.
“Once the investigation is completed we will see what can be learnt off the back of it.”
Minister Blair said with no flows on the horizon; not much could be done.
“The rain in Queensland over the last few days, will very unlikely make it across the border.
“Water NSW will be in regular contact with residents in that area.
“We are very close to commissioning the pipeline, but that doesn’t address the issue that the lakes are at low capacity and there is nothing coming down the system.
“As the Fisheries Minister, I am as concerned as anyone.”