What’s killing all the fish in this coastal town? Locals think they know
In the mid-morning sunshine, the Anglesea River was so calm this week the contours of its bed were clearly visible from the banks despite the water’s green hue.
Yet this apparently serene setting barely concealed a dispiriting reality. A closer inspection of the water revealed scores of dead fish lying at the bottom or bobbing upside down in the reeds. At the estuary, lifeless juvenile and mature fish lay scattered across the sand.
Long-term residents of Anglesea are familiar with so-called fish kill events, in which marine creatures are found dead en masse. Many fear the latest catastrophe has resulted from interference with the environment over decades and there will be more to come unless it stops.
Friends of Anglesea River co-founder Keith Shipton.Credit: Justin McManus
But mining and metal production company Alcoa, which previously mined coal nearby, insists its activities are not to blame, and acidification in the water is due to natural factors.
This week, authorities used an excavator to create an artificial opening of the river mouth to the ocean, attempting to improve the situation.
Friends of Anglesea River co-founder Keith Shipton has no doubt the latest environmental troubles in the river were caused by Alcoa pumping groundwater into its nearby coalmine pit. The company operated the mine from 1969 to 2015.
Fish kills have prompted warnings from local authorities in Anglesea. Credit: Justin McManus
Shipton said he was aware of about six fish kills in the Anglesea River in the past 25 years. He said Alcoa’s pumping of groundwater from the aquifer had created a “cone of depression” – an underground area where groundwater levels have dropped due to pumping.
“That’s important because the ground above the cone of depression is consequently very dry,” Shipton said. “It used to be wet.”
He said the Anglesea River was the “heart of the town”, and local businesses, particularly those in adventure sports, relied on it for their livelihoods.
An excavator opening artificially opening the river mouth. Credit: Justin McManus
The Friends of Anglesea River is now fighting Alcoa’s new plans to pump water to help fill the former mine pit. Both the Surf Coast Shire and Corangamite Catchment Management Authority made submissions opposing the proposal.
Shipton said Alcoa’s plan posed a serious threat to the river’s health.
“No good can come to the Anglesea River so long as there is pumping of the groundwater immediately beneath the catchment,” he said.
However, an Alcoa spokesman said the company took its environmental commitments seriously and insisted historical studies had determined its operations had no negative impacts on the river’s health.
Fish kills in Anglesea have alarmed residents. Credit: Justin McManus
“We continue to ensure all mine rehabilitation and closure works, including water management and use, are subject to rigorous design, testing and analysis,” he said.
The spokesman said Alcoa had conducted analysis of hydrogeological models, historical data, independent technical studies and groundwater pumping tests to develop a groundwater model.
“These have all confirmed the proposed extraction would have no adverse impact on groundwater dependent ecosystems, including the Anglesea River,” he said.
A Corangamite Catchment Management Authority spokeswoman said the river estuary currently had high acidity caused by naturally occurring acids in soils. The estuary was artificially opened on Wednesday to determine whether any environmental benefits could be achieved.
In a statement, Victoria’s Environment Protection Authority said it had been aware of the water quality issue related to the dead fish since August 5.
The Great Ocean Road Coast and Parks Authority has erected a sign at the river mouth warning against handling dead or dying fish. It says contact with the water might lead to skin or eye irritation.
A 2023 study conducted on behalf of the Corangamite Catchment Management Authority and Department of Environment, Energy and Climate Action found acid sulfate soils were naturally present in the environment. But it said other potential causes of acid sulfate soils becoming oxidised had been raised, including groundwater aquifer extraction between the 1970s and 2016.
The study reported other influences on the local environment included excavation of the Anglesea open cut coal mine pit, diversion of a creek around the former mine, and excavation of channels in the upper estuary in 1983.
The estuary of the Anglesea River has too much acidity. Credit: Justin McManus
Surf Coast Shire Mayor Mike Bodsworth, who lives in Anglesea, said he had seen eels, bream and mullet among the dead sea creatures in the river earlier this month.
“In an hour’s walk, you would probably see 100 dead fish,” he said. “It’s extremely distressing for people who live in Anglesea.”
Bodsworth said that while the acid events were sad, there was a good chance the river would recover naturally if groundwater extraction stopped.
“Monitoring bores clearly show groundwater recovery since pumping stopped,” he said.
Damien Cerantonio, a Great Ocean Road Regional Tourism board member and Anglesea business operator, said the river was central to the community and nature-based activities.
The former Anglesea coal mine is being rehabilitated, but many residents are opposed to pumping water to fill the pit. Credit: Eddie Jim
“It’s something we definitely need to fix as we approach the September school holidays,” he said.
But Cerantonio said he was more concerned as a resident who loved the local environment.
“That might escalate if we’re having this discussion in four weeks’ time and nothing is done,” he said. “Then it does become a real worry.”
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