South Australia's algal bloom has spread. Here's why the rest of Australia should be worried
As he lowered himself into the murky depths of the Yorke Peninsula, Stefan Andrews entered an environment both familiar and completely alien.
Usually, these sparkling waters would be alive with Port Jackson sharks and other fish, leafy sea dragons, octopus and molluscs.
But for months now, swaths of South Australia's coastal areas have been transformed into 'dead zones': starved of oxygen, overrun with algal blooms primarily caused by microalgae Karenia mikimotoi, and filled with the floating bodies of marine creatures.
The vast dead zones have stretched across central the state's coastlines, and now encroach on urban areas of Adelaide itself.
'The water was a neon green, and really low visibility, even though we'd had low winds for quite a few days, so you'd usually expect clear water at that time,' Andrews said of his foray into a dead zone under the Edithburgh Jetty.
Once he was below the water's surface, the scale of the disaster became clear.
'I immediately started seeing things that were dead and dying along the ocean floor,' the co-founder of the Great Southern Reef Foundation said.
'And quite strikingly, for me, was the jetty pylons, which were usually covered in these beautiful filter-feeding sponges and invertebrate life. And [the sponges and invertebrates] were all falling apart. Their tissues were decomposing right before my very eyes.'
Karenia mikimotoi is toxic to fish and invertebrates, and can cause respiratory and eye irritations and rashes in humans. People who ingest alga-contaminated water can also experience gastro or flu-like symptoms.
'It acts like a toxic blanket that suffocates marine life,' said OzFish South Australia project manager Brad Martin.
'It can suffocate fish from their gills, cause haemorrhaging by attacking their red blood cells, and act as a neurotoxin and attack the fish's nervous system and brain, causing unusual behaviour.'
Among its victims have been sharks, dolphins, rays, leafy seadragons, cuttlefish, octopus and little penguins. Distressing footage posted online shows an alga-affected shark swimming erratically along the shore on the south coast, apparently searching for more oxygen.
Janine Baker, a marine scientist of 35 years, said she had never seen anything like it.
'There are fishers in those areas who say they're not catching anything at all,' she said.
'And then there's all the peculiar behaviours [of marine animals] as well. Fishes [and] sharks driving themselves ashore ... and on the southern Yorke Peninsula, and also the western side of Gulf St Vincent, hundreds of rays washing up, for example, even 100 on some of the beaches.'
The bloom has mainly been concentrated in the central coastal areas of South Australia. Baker said it was, 'without doubt, an environmental disaster, and there will be long-term marine environmental, social and economic impacts'.
The algal blooms have been fed by a combination of factors.
The state's environment department says 'plausible' contributing factors are record marine temperatures, the 2022-23 Murray River floods, which washed nutrients into the sea, and 'cold-water upwelling' during 2023-24, which brought nutrients to the surface.
Australia has since last year been enveloped in a marine heatwave stretching for 40 million square kilometres across the south-west Pacific, bringing intense heat, extreme rainfall and sea-level rises.
As marine heatwaves become more common, experts warn algal blooms – like those that hit southern California this year for the fourth year running – will also become more common.
A joint community-based data gathering project on online platform iNaturalist has attracted more than 4680 observations of species between Ceduna in the state's west, to Nelson just over the border in Victoria. The cause of death has not been confirmed in most cases, although Baker said the majority of deaths were recorded in bloom-affected areas.
The most commonly recorded species of dead sea creatures was southern fiddler rays. So far, 330 species have been recorded in the database.
Andrews warned that what he's witnessed in South Australia could happen elsewhere.
'It's definitely a warning sign that marine heat waves are likely to be happening more frequently, [and] being more severe,' he said.
A spokeswoman for the South Australian Environment Department said authorities were monitoring the situation through daily satellite observations and weekly water testing in the Coorong.
'Similar blooms around the world have lasted from a week to several months, depending on wind, rain and ocean temperatures,' she said.
The Great Southern Reef Foundation this week sent small teams of divers to survey an area off the Yorke Peninsula that has been heavily hit by algal blooms.
'One of the alarming things is there's basically next to no one documenting what's happening,' Andrews said.
'We're missing opportunities here to actually learn from something that could happen more and more frequently.'
Loading
The Karenia outbreak was first discovered in March on the Fleurieu Peninsula. It has since spread to the Yorke Peninsula and Kangaroo Island.
Among the first people to publicly sound the alarm about the toxic blooms was surfer and part-time photographer Anthony Rowland.
On March 17, he photographed a thick, tan-coloured foam that had developed on Waitpinga Beach near Victor Harbour, south of Adelaide. Andrews and other surfers who entered the water later experienced respiratory difficulties and blurred vision.
'While we were out there we started coughing,' he told the ABC.
'[We] came in [from the beach] and we kept coughing after walking up the hill, and a few people in the car park came over, and they said that they'd experienced the same coughing, and they hadn't even hit the water yet.'
Since then, beachgoers and scientists have documented a vast array of sea creatures washing up dead along the South Australian coastline.
In the past weeks, Karenia advanced into the Coorong, an internationally significant RAMSAR wetland on the mouth of the Murray River.
A photograph captured by Coorong Wild Seafood co-owner Glen Hill several weeks ago showed a stew of dead polychaete worms so dense, it would be impossible to put a pencil through the surface of the water without touching multiple bodies.
'You can't do justice [with photographs] to how much of it there is,' said Hill, who has fished these waters for 35 years.
'There's 50 metres or something [of worms] washed up in one area. So there's 100 kilos or something of it sitting in one small area. It's absolutely devastating.'
'I broke down when I saw it.'
Hill has been advocating for years for authorities to release more environmental flows into the Murray Darling System, which covers about one-seventh of the Australian continent, and concludes at the Coorong National Park at the mouth of the Murray.
'It's just absolutely on the edge of survival,' Hill said of the Coorong lagoon and coastline.
The South Australian government has urged people not to swim in foamy or discoloured water, or where there is sick or dead marine life. Dead or dying marine life found on the beach should not be consumed.
'A glimmer of hope might be that the deeper reefs may have been a bit of a refuge from some of the algae that was sitting on the surface of the water,' said Andrews.
'But we don't know.'
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The Age
20 hours ago
- The Age
South Australia's algal bloom has spread. Here's why the rest of Australia should be worried
As he lowered himself into the murky depths of the Yorke Peninsula, Stefan Andrews entered an environment both familiar and completely alien. Usually, these sparkling waters would be alive with Port Jackson sharks and other fish, leafy sea dragons, octopus and molluscs. But for months now, swaths of South Australia's coastal areas have been transformed into 'dead zones': starved of oxygen, overrun with algal blooms primarily caused by microalgae Karenia mikimotoi, and filled with the floating bodies of marine creatures. The vast dead zones have stretched across central the state's coastlines, and now encroach on urban areas of Adelaide itself. 'The water was a neon green, and really low visibility, even though we'd had low winds for quite a few days, so you'd usually expect clear water at that time,' Andrews said of his foray into a dead zone under the Edithburgh Jetty. Once he was below the water's surface, the scale of the disaster became clear. 'I immediately started seeing things that were dead and dying along the ocean floor,' the co-founder of the Great Southern Reef Foundation said. 'And quite strikingly, for me, was the jetty pylons, which were usually covered in these beautiful filter-feeding sponges and invertebrate life. And [the sponges and invertebrates] were all falling apart. Their tissues were decomposing right before my very eyes.' Karenia mikimotoi is toxic to fish and invertebrates, and can cause respiratory and eye irritations and rashes in humans. People who ingest alga-contaminated water can also experience gastro or flu-like symptoms. 'It acts like a toxic blanket that suffocates marine life,' said OzFish South Australia project manager Brad Martin. 'It can suffocate fish from their gills, cause haemorrhaging by attacking their red blood cells, and act as a neurotoxin and attack the fish's nervous system and brain, causing unusual behaviour.' Among its victims have been sharks, dolphins, rays, leafy seadragons, cuttlefish, octopus and little penguins. Distressing footage posted online shows an alga-affected shark swimming erratically along the shore on the south coast, apparently searching for more oxygen. Janine Baker, a marine scientist of 35 years, said she had never seen anything like it. 'There are fishers in those areas who say they're not catching anything at all,' she said. 'And then there's all the peculiar behaviours [of marine animals] as well. Fishes [and] sharks driving themselves ashore ... and on the southern Yorke Peninsula, and also the western side of Gulf St Vincent, hundreds of rays washing up, for example, even 100 on some of the beaches.' The bloom has mainly been concentrated in the central coastal areas of South Australia. Baker said it was, 'without doubt, an environmental disaster, and there will be long-term marine environmental, social and economic impacts'. The algal blooms have been fed by a combination of factors. The state's environment department says 'plausible' contributing factors are record marine temperatures, the 2022-23 Murray River floods, which washed nutrients into the sea, and 'cold-water upwelling' during 2023-24, which brought nutrients to the surface. Australia has since last year been enveloped in a marine heatwave stretching for 40 million square kilometres across the south-west Pacific, bringing intense heat, extreme rainfall and sea-level rises. As marine heatwaves become more common, experts warn algal blooms – like those that hit southern California this year for the fourth year running – will also become more common. A joint community-based data gathering project on online platform iNaturalist has attracted more than 4680 observations of species between Ceduna in the state's west, to Nelson just over the border in Victoria. The cause of death has not been confirmed in most cases, although Baker said the majority of deaths were recorded in bloom-affected areas. The most commonly recorded species of dead sea creatures was southern fiddler rays. So far, 330 species have been recorded in the database. Andrews warned that what he's witnessed in South Australia could happen elsewhere. 'It's definitely a warning sign that marine heat waves are likely to be happening more frequently, [and] being more severe,' he said. A spokeswoman for the South Australian Environment Department said authorities were monitoring the situation through daily satellite observations and weekly water testing in the Coorong. 'Similar blooms around the world have lasted from a week to several months, depending on wind, rain and ocean temperatures,' she said. The Great Southern Reef Foundation this week sent small teams of divers to survey an area off the Yorke Peninsula that has been heavily hit by algal blooms. 'One of the alarming things is there's basically next to no one documenting what's happening,' Andrews said. 'We're missing opportunities here to actually learn from something that could happen more and more frequently.' Loading The Karenia outbreak was first discovered in March on the Fleurieu Peninsula. It has since spread to the Yorke Peninsula and Kangaroo Island. Among the first people to publicly sound the alarm about the toxic blooms was surfer and part-time photographer Anthony Rowland. On March 17, he photographed a thick, tan-coloured foam that had developed on Waitpinga Beach near Victor Harbour, south of Adelaide. Andrews and other surfers who entered the water later experienced respiratory difficulties and blurred vision. 'While we were out there we started coughing,' he told the ABC. '[We] came in [from the beach] and we kept coughing after walking up the hill, and a few people in the car park came over, and they said that they'd experienced the same coughing, and they hadn't even hit the water yet.' Since then, beachgoers and scientists have documented a vast array of sea creatures washing up dead along the South Australian coastline. In the past weeks, Karenia advanced into the Coorong, an internationally significant RAMSAR wetland on the mouth of the Murray River. A photograph captured by Coorong Wild Seafood co-owner Glen Hill several weeks ago showed a stew of dead polychaete worms so dense, it would be impossible to put a pencil through the surface of the water without touching multiple bodies. 'You can't do justice [with photographs] to how much of it there is,' said Hill, who has fished these waters for 35 years. 'There's 50 metres or something [of worms] washed up in one area. So there's 100 kilos or something of it sitting in one small area. It's absolutely devastating.' 'I broke down when I saw it.' Hill has been advocating for years for authorities to release more environmental flows into the Murray Darling System, which covers about one-seventh of the Australian continent, and concludes at the Coorong National Park at the mouth of the Murray. 'It's just absolutely on the edge of survival,' Hill said of the Coorong lagoon and coastline. The South Australian government has urged people not to swim in foamy or discoloured water, or where there is sick or dead marine life. Dead or dying marine life found on the beach should not be consumed. 'A glimmer of hope might be that the deeper reefs may have been a bit of a refuge from some of the algae that was sitting on the surface of the water,' said Andrews. 'But we don't know.'
Sydney Morning Herald
20 hours ago
- Sydney Morning Herald
South Australia's algal bloom has spread. Here's why the rest of Australia should be worried
As he lowered himself into the murky depths of the Yorke Peninsula, Stefan Andrews entered an environment both familiar and completely alien. Usually, these sparkling waters would be alive with Port Jackson sharks and other fish, leafy sea dragons, octopus and molluscs. But for months now, swaths of South Australia's coastal areas have been transformed into 'dead zones': starved of oxygen, overrun with algal blooms primarily caused by microalgae Karenia mikimotoi, and filled with the floating bodies of marine creatures. The vast dead zones have stretched across central the state's coastlines, and now encroach on urban areas of Adelaide itself. 'The water was a neon green, and really low visibility, even though we'd had low winds for quite a few days, so you'd usually expect clear water at that time,' Andrews said of his foray into a dead zone under the Edithburgh Jetty. Once he was below the water's surface, the scale of the disaster became clear. 'I immediately started seeing things that were dead and dying along the ocean floor,' the co-founder of the Great Southern Reef Foundation said. 'And quite strikingly, for me, was the jetty pylons, which were usually covered in these beautiful filter-feeding sponges and invertebrate life. And [the sponges and invertebrates] were all falling apart. Their tissues were decomposing right before my very eyes.' Karenia mikimotoi is toxic to fish and invertebrates, and can cause respiratory and eye irritations and rashes in humans. People who ingest alga-contaminated water can also experience gastro or flu-like symptoms. 'It acts like a toxic blanket that suffocates marine life,' said OzFish South Australia project manager Brad Martin. 'It can suffocate fish from their gills, cause haemorrhaging by attacking their red blood cells, and act as a neurotoxin and attack the fish's nervous system and brain, causing unusual behaviour.' Among its victims have been sharks, dolphins, rays, leafy seadragons, cuttlefish, octopus and little penguins. Distressing footage posted online shows an alga-affected shark swimming erratically along the shore on the south coast, apparently searching for more oxygen. Janine Baker, a marine scientist of 35 years, said she had never seen anything like it. 'There are fishers in those areas who say they're not catching anything at all,' she said. 'And then there's all the peculiar behaviours [of marine animals] as well. Fishes [and] sharks driving themselves ashore ... and on the southern Yorke Peninsula, and also the western side of Gulf St Vincent, hundreds of rays washing up, for example, even 100 on some of the beaches.' The bloom has mainly been concentrated in the central coastal areas of South Australia. Baker said it was, 'without doubt, an environmental disaster, and there will be long-term marine environmental, social and economic impacts'. The algal blooms have been fed by a combination of factors. The state's environment department says 'plausible' contributing factors are record marine temperatures, the 2022-23 Murray River floods, which washed nutrients into the sea, and 'cold-water upwelling' during 2023-24, which brought nutrients to the surface. Australia has since last year been enveloped in a marine heatwave stretching for 40 million square kilometres across the south-west Pacific, bringing intense heat, extreme rainfall and sea-level rises. As marine heatwaves become more common, experts warn algal blooms – like those that hit southern California this year for the fourth year running – will also become more common. A joint community-based data gathering project on online platform iNaturalist has attracted more than 4680 observations of species between Ceduna in the state's west, to Nelson just over the border in Victoria. The cause of death has not been confirmed in most cases, although Baker said the majority of deaths were recorded in bloom-affected areas. The most commonly recorded species of dead sea creatures was southern fiddler rays. So far, 330 species have been recorded in the database. Andrews warned that what he's witnessed in South Australia could happen elsewhere. 'It's definitely a warning sign that marine heat waves are likely to be happening more frequently, [and] being more severe,' he said. A spokeswoman for the South Australian Environment Department said authorities were monitoring the situation through daily satellite observations and weekly water testing in the Coorong. 'Similar blooms around the world have lasted from a week to several months, depending on wind, rain and ocean temperatures,' she said. The Great Southern Reef Foundation this week sent small teams of divers to survey an area off the Yorke Peninsula that has been heavily hit by algal blooms. 'One of the alarming things is there's basically next to no one documenting what's happening,' Andrews said. 'We're missing opportunities here to actually learn from something that could happen more and more frequently.' Loading The Karenia outbreak was first discovered in March on the Fleurieu Peninsula. It has since spread to the Yorke Peninsula and Kangaroo Island. Among the first people to publicly sound the alarm about the toxic blooms was surfer and part-time photographer Anthony Rowland. On March 17, he photographed a thick, tan-coloured foam that had developed on Waitpinga Beach near Victor Harbour, south of Adelaide. Andrews and other surfers who entered the water later experienced respiratory difficulties and blurred vision. 'While we were out there we started coughing,' he told the ABC. '[We] came in [from the beach] and we kept coughing after walking up the hill, and a few people in the car park came over, and they said that they'd experienced the same coughing, and they hadn't even hit the water yet.' Since then, beachgoers and scientists have documented a vast array of sea creatures washing up dead along the South Australian coastline. In the past weeks, Karenia advanced into the Coorong, an internationally significant RAMSAR wetland on the mouth of the Murray River. A photograph captured by Coorong Wild Seafood co-owner Glen Hill several weeks ago showed a stew of dead polychaete worms so dense, it would be impossible to put a pencil through the surface of the water without touching multiple bodies. 'You can't do justice [with photographs] to how much of it there is,' said Hill, who has fished these waters for 35 years. 'There's 50 metres or something [of worms] washed up in one area. So there's 100 kilos or something of it sitting in one small area. It's absolutely devastating.' 'I broke down when I saw it.' Hill has been advocating for years for authorities to release more environmental flows into the Murray Darling System, which covers about one-seventh of the Australian continent, and concludes at the Coorong National Park at the mouth of the Murray. 'It's just absolutely on the edge of survival,' Hill said of the Coorong lagoon and coastline. The South Australian government has urged people not to swim in foamy or discoloured water, or where there is sick or dead marine life. Dead or dying marine life found on the beach should not be consumed. 'A glimmer of hope might be that the deeper reefs may have been a bit of a refuge from some of the algae that was sitting on the surface of the water,' said Andrews. 'But we don't know.'
7NEWS
03-06-2025
- 7NEWS
South Australia's Coorong at risk as algae outbreak puts fragile ecosystem on the brink
The toxic algae bloom that has plagued South Australian coastlines since March has, 'unfortunately,' made its way into one of the state's most fragile ecosystems — the Coorong. Last week's powerful storm surge was initially welcomed, with hopes it would push cold, salty ocean water onto the shore to disrupt the bloom of the toxic micro-algae karenia mikimotoi algae. However, those same strong currents instead drove the algae back up the Murray River at Goolwa, entering the Coorong through the Murray Mouth — where the river meets the Southern Ocean. With ongoing drought conditions and tidal influences, the algae has now found an ideal environment in which it may be impossible to remove. Previously responsible for murky waters and thick sea foam along the Fleurieu Peninsula, Karenia mikimotoi is also suspected to be linked to the recent deaths of several sharks on Adelaide beaches. Ecologist and Coorong Environmental Trustee Faith Coleman expressed grave concern about the algae's intrusion into the Coorong's intricate ecosystem. 'Unfortunately, that amazing storm tide managed to push the Karenia straight into the northern lagoon of the Coorong, where it is blooming quite happily,' she said. 'Because of the unique nature of coastal lagoons, once something gets in, it rarely gets out.' The algae has now established itself in a 'sweet spot' at the end of the northern lagoon, where conditions — including high salinity, warm temperatures, and stagnant water — are perfect for it to thrive. Up to two metres of decomposing marine life, described as 'worm soup,' has already been found, with dead tubeworms and larvae washing ashore. Experts warn this could disrupt the already delicate food chain in the area. 'Many of the small organisms at the base of the food chain — those vital to shorebirds and fish — are now washing up dead,' Coleman said. 'There isn't anything that lives or grows in the water of the Coorong that is safe from this.' Local fisherman Glen Hill, owner of Coorong Wild Seafood, said the situation could devastate the region's fishing industry. 'I've bashed my head against the side of the chiller in frustration. I've cried my eyes out,' Hill told 7NEWS. 'If we lose the bottom of the food chain, what do the fish eat? 'Potentially, we could lose everything.' The storm system also stirred up sediment and, combined with the lack of fresh water, has spiked salinity levels in the Coorong. This has led to further environmental stress, with fish such as mullet, mulloway, and bony bream suffering visible gill damage — likely caused by the increasingly toxic conditions. The Department of Primary Industries and Regions (PIRSA) confirmed they are investigating recent fish deaths but have not yet officially linked them to Karenia mikimotoi. 'We continue to work with other relevant government agencies on the current Karenia species algal bloom and associated fish deaths that have been occurring in South Australian waters since March,' a PIRSA spokesperson said in a statement to 7NEWS. Investigations are underway into reports of a bony bream fish kill in Woods Well Bay and a polychaete worm die-off near Long Point. Water samples have been collected and results are pending. 'Our role is to investigate any infectious or notifiable animal diseases that may have caused the fish deaths,' PIRSA said. The Department for Environment and Water (DEW) also confirmed the algae's entry into the Coorong was a known risk — and that any intervention, such as opening the barrages to flush water, could worsen the situation. 'The Coorong is open to the sea via the Murray Mouth and cannot be closed off from the ocean,' a DEW spokesperson said. 'During adverse weather and high tides, SA Water operates the barrages to minimise seawater entering Lake Alexandrina and to limit salinity impacts from reverse flows.' They added that although the tide pushed the algae in, the Coorong's natural connection to the Murray Mouth meant this could not be prevented. 'Pushing more water through the barrages to try to flush out the algae is unlikely to be effective and could risk spreading the bloom further south,' the spokesperson said. DEW confirmed it will continue monitoring the Coorong's northern lagoon and reaffirmed the State Government's commitment to protecting the area's ecological health. In the meantime, PIRSA and SA Health have advised the public not to collect or eat any dead or dying fish or marine organisms found along the shore. To report unusual sightings of fish kills or affected marine life, residents are urged to contact FISHWATCH on 1800 065 522. Concerns about water quality can be reported to the EPA at 1800 623 445 or by emailing yourepa@
