Zac Taylor has been navigating the Curdies River, along Victoria's Great Ocean Road, as a commercial eel fisher for decades, just like his father before him.
But never before has he seen tonnes of dead bream lying belly-up for kilometres.
"Dad started in '76, I started by myself in 2009. I'm on the river probably six months of the year fishing," Mr Taylor said.
"This is the first time I've seen bream dead in those numbers in this river."
Mr Taylor went up river after receiving a message from a friend that tonnes of fish were dead.
He documented the aftermath and reported it to the Victorian Fisheries Association.
"There was just dead fish from the start of the river where it meets the lake for about three kilometres upstream," he said.
"In places I would have been able to fill a 50-kilo fish box in about 20 metres."
Mr Taylor believes the bottom-dwelling bream suffocated due to a lack of oxygen in the river, the consequence of a toxic blue-green algae bloom.
The Department of Environment, Land, Water and Planning said it had sampled the water and confirmed that an algal bloom was affecting the Peterborough Coastal Reserve, including Curdies Inlet.
It also confirmed reports of a "localised small fish kill caused by the bloom", which it said was expected to remain until there was significant rainfall or cooler conditions slowed the algae.
The department warned people to avoid direct contact with the affected water, including swimming, fishing and during boating activities, nor should they eat whole fish, shellfish or crustaceans from the river.
Smells like rotten eggs this Easter
Usually a place abuzz with budding fishers, Mr Taylor said he expected Curdies Estuary to be eerily quiet during the school holidays.
"It smells like rotten eggs, just rotten — people are not going to come here this Easter because of it, unfortunately.
"Normally they'd come down here and the kids would be kayaking and fishing and swimming and playing in the sand."
The toxic water has distressed young fisher Dusty Lynch, who holidays with his mum at the estuary over summer each year, and is saddened by seeing so many dead fish.
The 10-year-old loves fishing and nature and usually fishes in the estuary every day, but his mum has not let him near the water since January.
"Important animals are dying, we need to step up and help these animals," he said.
"All those fish are dead because of this algae, which means we have to step up and help nature.
"I want the river to be like it was for my mum when she was young — beautiful and with all the fish in the water."
Replanting the river edges could help
Ecologist Jules Mondon from Deakin University in Warrnambool said the level of blue-green algae blooms depended on water temperature and the amount of phosphorous in the water.
"Summer provides ideal growing conditions — warmer water, longer daylight hours, and the little bacteria are actually able to fix nitrogen," Dr Mondon said.
"But they're not limited by how much nitrogen is present in the water; if there's enough phosphate in the water, then that provides an ideal condition for them to bloom."
Zac Taylor attributes the higher frequency of algal blooms to effluent, sewage outfall and run-off from dairy farms.
Dr Mondon said while there were associations, blue-green algae blooms were more complicated than just nutrient loading.
"We have had perhaps more algal blooms in estuaries that flow through agricultural land because we do get nutrient run-off from agricultural land.
"But we do also get blue-green algal blooms in some of the estuaries actually on the Otways where there is no agriculture."
She added there had not been fish killed by such blooms in the Otways, and that reducing nutrients in the river could certainly help, as could reinstating riparian vegetation on farms.
"What we need to be looking at collectively is our wastewater systems and our sewage treatment systems.
"Their aim is to extract as much of that nutrient as possible before the water is released into a particular river or even directly out to sea.
"The other thing I think we could perhaps increase is this concept of a vegetation buffer — trying to prevent as much of that surface nutrient run-off entering the waterway itself by generating these growth corridors up and down all our waterways."
Dr Mondon said that by revegetating river frontage along the river as it travelled through farms, excess fertiliser and manure could be taken up by the plants and used, preventing the nitrogen and phosphorous from entering the river system.
The future of the river
As someone who has spent half his life sustainably earning an income from its waters, Zac Taylor has a vested interest in how the river's health is managed.
"I'm a greenie as well because I want to see the place healthy for my income," he said.
"We've been here sustainably for the last 40-odd years now, and I'm still catching the same amount of fish as what dad was catching back in the '70s.
"I want that to continue to happen."
Dr Mondon said climate change would compound the issues already occurring on the river.
"This is not only a challenge in this region, but it's going to be Australia-wide and globally," she said.
"Our summers are going to get drier, and occasionally we'll have these really heavy thunderstorms, they'll bring in a lot of flushing of that surface nutrient down into the estuaries.
"It's a balance; as our rainfall decreases, our need for primary industry to maintain its production levels remains."
