The Department of Primary Industries investigated a mass fish kill near Moruya on Thursday March 14.
Low water levels are the suspected cause behind hundreds of dead fish along the shoreline of Meringo Lake.
On Wednesday, March 13, Greens candidates and NSW Upper House MP David Shoebridge reported a mass of dead bream, eels, mullet, fingerlings and prawns.
The lake, located south of Moruya, is a saline coastal lagoon which has an intermittently closed entrance.
Bega Greens candidate Will Douglas said he was distressed at the sight of dead fish scattered along the banks.
“It’s the latest evidence that our coastal environment is under serious threat," he said.
Wallagoot Lake, south of Bega, is among estuaries in NSW which recently had reported fish kills due to a combination of environmental factors.
The DPI said the main species observed included black bream, gudgeons, mullet, eels and luderick.
"The suspected cause is related to the very low water levels at Lake Meringo and the resulting poor water quality this causes," a DPI spokesperson said.
"At these low levels, coastal lakes are very susceptible to high water temps, algal growth and low dissolved oxygen.
"Poor water quality in our coastal lakes is likely to continue without significant rainfall," the spokesperson said.
Mr Shoebridge blamed heat and drought, but also questioned wider policies.
“The record summer temperatures and low rainfall are the most obvious explanations for this fish kill. However, we can’t rule out the impacts of local land use as potentially contributing as well," he said.
“Seeing these thousands of dead fish really brings home the environmental damage we are doing to the planet and the scale of the challenge before us to deal with climate change.
“We only have a short time to act. If we don’t move to 100 per cent renewable energy and rapidly reduce our carbon footprint, this will keep happening," he said.
Mr Douglas said the NSW Government and Eurobodalla Shire Council must protect forested lands and buffers to coastal lagoons.
“I call on the NSW Government and the local council to stop their attacks on environmental protections in Eurobodalla and instead commit to working with the community to save the local environment," he said.
DPI Fisheries are continuing to work with National Parks and Eurobodalla Council to monitor the lake.
The community is reminded to report any observations of fish kills to Fishers Watch phone line on 1800 043 536.