Algal bloom turns coast into a 'marine graveyard'
The microalgae, karenia mikimotoi, was identified off South Australia's Fleurieu Peninsula in March.
The bloom grew to an unprecedented scale, close to the size of Kangaroo Island, at more than 4400 sq km, and as deep as 25m.
It's now breaking up and has spread into most of Gulf St Vincent, including along Adelaide's beaches and south into the Coorong wetlands.
There have been hundreds of reports of marine deaths, ranging from sharks and penguins to popular fishing species such as flathead, squid, crabs, and rock lobsters.
Greens senator Sarah Hanson-Young said the bloom was a horrific and heartbreaking "environmental catastrophe".
"When parliament resumes in two weeks time in Canberra, I will be moving for a federal parliamentary inquiry," she told reporters on Friday.
"We need proper investigation and proper federal support."
Beaches have become "graveyards" for marine species, and the fishing and tourism industries have been significantly impacted, she said.
Ms Hanson-Young claimed the federal government ignored warnings about the algae before it took hold.
"It is very concerning that the country's leading marine scientists have been ignored and dismissed," she said.
Experts believe there are three potential plausible contributing factors causing the bloom, the SA government said.
One is a marine heatwave that started in September 2024, with sea temperatures about 2.5°C warmer than usual, combined with calm conditions, light winds and small swells.
Another is the 2022-23 River Murray flood washing extra nutrients into the sea and an unprecedented cold-water upwelling in summer 2023-24 that brought nutrient-rich water to the surface.
SA Environment Minister Susan Close said the bloom had lasted longer than experts thought it would.
"Now that it's here, it's going to be hard to get rid of," she said.
"It's easy to feel helpless, because the bloom itself is something that we can't stop."
The SA government met with impacted commercial fishers, tourism operators and local councils about support packages.
"It's been very, very distressing for people, and it's affected people's livelihoods," Ms Close said.
The state government is also starting work on a recovery plan.
This could include creating artificial reefs to help build up marine life, restocking fish into the ocean and increasing the number of marine sanctuary zones along the coast.
"Although we're looking forward to the end of this experience, we cannot assume it's the last time we've had it," Ms Close said.
Karenia mikimotoi is in SA's waterways and waiting to come back to life when conditions are right, she said.
"This is what climate change means."
OzFish previously said more than 200 species of fish, sharks and other marine creatures had been killed by the algae bloom.
This includes rarely encountered deepwater sharks and leafy sea dragons, and recreational fishing species like flathead, squid, crabs, and rock lobsters.
Karenia mikimotoi is toxic to fish and invertebrates but does not cause long-term harmful effects in humans.
But, exposure to discoloured or foamy water can cause short-term skin or eye irritation and respiratory symptoms, including coughing or shortness of breath.
The last large event of this type of algae recorded in SA was at Coffin Bay in 2014.
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The Advertiser
5 days ago
- The Advertiser
'Incredibly disturbing': federal help for algae crisis
The federal government has thrown its support behind a state battling a massive, toxic algal bloom that has devastated the marine environment, but says the crisis cannot officially be declared a natural disaster. The bloom of the microalgae species karenia mikimotoi was identified off South Australia's Fleurieu Peninsula in March, and grew to more than 4400 sq km, close to the size of Kangaroo Island. It has been breaking up in recent weeks, spreading north into Spencer Gulf, south into the Coorong wetlands and along Adelaide's beaches in Gulf St Vincent into the Port River, killing tens of thousands of marine animals. Environment Minister Murray Watt said the bloom and its impacts were "incredibly disturbing", as he announced a $14 million federal funding package for the SA government. The money is likely to be used to pay for the clean-up of dead marine life from SA's beaches, support impacted businesses, bolster community awareness about the bloom and invest in science and research to better understand the incident. "There's no doubting whatsoever that this is a very serious environmental event facing South Australia," Mr Watt told reporters on Monday. "We are in uncharted waters here." Asked if the bloom and its impact should be declared a natural disaster, Mr Watt said it was not possible under the existing definition despite calls from scientists, the Greens and SA's Labor premier. A natural disaster declaration would trigger special federal assistance measures to support individuals, businesses and communities in their recovery. "We have managed outside the usual natural disaster framework to marshal the type of resources that South Australia has asked for," Mr Watt said. "One of the difficulties has been understanding exactly what its impacts are and what sort of response is required. "We won't solve this overnight and we are, to some extent, relying on weather conditions to help disperse the algal bloom." The algal bloom is naturally occurring, but the state's environment department has listed potential contributing factors including a marine heatwave that started in 2024, when sea temperatures were about 2.5C warmer than usual, combined with calm conditions. Another was the 2022/23 River Murray flood that washed extra nutrients into the sea followed by an unprecedented cold-water upwelling in the summer of 2023/24 that brought nutrient-rich water to the surface. Marine ecologist Dominic McAfee said the mortality in most heavily impacted areas was "extremely confronting". "It seems like almost everything has died," Dr McAfee, from the University of Adelaide's Environment Institute, told AAP. "We don't know how long it's going to go on, and so the impacts we're seeing now could just be the start of something more prolonged." Dr McAfee said it was hoped winter winds and swells would "disperse and nullify" the algae bloom, but it hadn't happened. "It seems to be more resilient than anticipated ... it's still at high fatal concentrations for a lot of marine life, and we're still seeing marine life wash up," he said. "And there's a chance that it will continue for many more months." Authorities previously said the algae had killed tens of thousands of marine animals from almost 450 species. Dr McAfee said it was the "tip of the iceberg" because the project monitoring the deaths only recorded species washed ashore, and it would not have accounted for smaller vertebrates and less well-known species. "There are little bits of resilience as well ... so it's understanding how those resilient pockets of the ecosystem persist through the bloom," he said. The federal government has thrown its support behind a state battling a massive, toxic algal bloom that has devastated the marine environment, but says the crisis cannot officially be declared a natural disaster. The bloom of the microalgae species karenia mikimotoi was identified off South Australia's Fleurieu Peninsula in March, and grew to more than 4400 sq km, close to the size of Kangaroo Island. It has been breaking up in recent weeks, spreading north into Spencer Gulf, south into the Coorong wetlands and along Adelaide's beaches in Gulf St Vincent into the Port River, killing tens of thousands of marine animals. Environment Minister Murray Watt said the bloom and its impacts were "incredibly disturbing", as he announced a $14 million federal funding package for the SA government. The money is likely to be used to pay for the clean-up of dead marine life from SA's beaches, support impacted businesses, bolster community awareness about the bloom and invest in science and research to better understand the incident. "There's no doubting whatsoever that this is a very serious environmental event facing South Australia," Mr Watt told reporters on Monday. "We are in uncharted waters here." Asked if the bloom and its impact should be declared a natural disaster, Mr Watt said it was not possible under the existing definition despite calls from scientists, the Greens and SA's Labor premier. A natural disaster declaration would trigger special federal assistance measures to support individuals, businesses and communities in their recovery. "We have managed outside the usual natural disaster framework to marshal the type of resources that South Australia has asked for," Mr Watt said. "One of the difficulties has been understanding exactly what its impacts are and what sort of response is required. "We won't solve this overnight and we are, to some extent, relying on weather conditions to help disperse the algal bloom." The algal bloom is naturally occurring, but the state's environment department has listed potential contributing factors including a marine heatwave that started in 2024, when sea temperatures were about 2.5C warmer than usual, combined with calm conditions. Another was the 2022/23 River Murray flood that washed extra nutrients into the sea followed by an unprecedented cold-water upwelling in the summer of 2023/24 that brought nutrient-rich water to the surface. Marine ecologist Dominic McAfee said the mortality in most heavily impacted areas was "extremely confronting". "It seems like almost everything has died," Dr McAfee, from the University of Adelaide's Environment Institute, told AAP. "We don't know how long it's going to go on, and so the impacts we're seeing now could just be the start of something more prolonged." Dr McAfee said it was hoped winter winds and swells would "disperse and nullify" the algae bloom, but it hadn't happened. "It seems to be more resilient than anticipated ... it's still at high fatal concentrations for a lot of marine life, and we're still seeing marine life wash up," he said. "And there's a chance that it will continue for many more months." Authorities previously said the algae had killed tens of thousands of marine animals from almost 450 species. Dr McAfee said it was the "tip of the iceberg" because the project monitoring the deaths only recorded species washed ashore, and it would not have accounted for smaller vertebrates and less well-known species. "There are little bits of resilience as well ... so it's understanding how those resilient pockets of the ecosystem persist through the bloom," he said. The federal government has thrown its support behind a state battling a massive, toxic algal bloom that has devastated the marine environment, but says the crisis cannot officially be declared a natural disaster. The bloom of the microalgae species karenia mikimotoi was identified off South Australia's Fleurieu Peninsula in March, and grew to more than 4400 sq km, close to the size of Kangaroo Island. It has been breaking up in recent weeks, spreading north into Spencer Gulf, south into the Coorong wetlands and along Adelaide's beaches in Gulf St Vincent into the Port River, killing tens of thousands of marine animals. Environment Minister Murray Watt said the bloom and its impacts were "incredibly disturbing", as he announced a $14 million federal funding package for the SA government. The money is likely to be used to pay for the clean-up of dead marine life from SA's beaches, support impacted businesses, bolster community awareness about the bloom and invest in science and research to better understand the incident. "There's no doubting whatsoever that this is a very serious environmental event facing South Australia," Mr Watt told reporters on Monday. "We are in uncharted waters here." Asked if the bloom and its impact should be declared a natural disaster, Mr Watt said it was not possible under the existing definition despite calls from scientists, the Greens and SA's Labor premier. A natural disaster declaration would trigger special federal assistance measures to support individuals, businesses and communities in their recovery. "We have managed outside the usual natural disaster framework to marshal the type of resources that South Australia has asked for," Mr Watt said. "One of the difficulties has been understanding exactly what its impacts are and what sort of response is required. "We won't solve this overnight and we are, to some extent, relying on weather conditions to help disperse the algal bloom." The algal bloom is naturally occurring, but the state's environment department has listed potential contributing factors including a marine heatwave that started in 2024, when sea temperatures were about 2.5C warmer than usual, combined with calm conditions. Another was the 2022/23 River Murray flood that washed extra nutrients into the sea followed by an unprecedented cold-water upwelling in the summer of 2023/24 that brought nutrient-rich water to the surface. Marine ecologist Dominic McAfee said the mortality in most heavily impacted areas was "extremely confronting". "It seems like almost everything has died," Dr McAfee, from the University of Adelaide's Environment Institute, told AAP. "We don't know how long it's going to go on, and so the impacts we're seeing now could just be the start of something more prolonged." Dr McAfee said it was hoped winter winds and swells would "disperse and nullify" the algae bloom, but it hadn't happened. "It seems to be more resilient than anticipated ... it's still at high fatal concentrations for a lot of marine life, and we're still seeing marine life wash up," he said. "And there's a chance that it will continue for many more months." Authorities previously said the algae had killed tens of thousands of marine animals from almost 450 species. Dr McAfee said it was the "tip of the iceberg" because the project monitoring the deaths only recorded species washed ashore, and it would not have accounted for smaller vertebrates and less well-known species. "There are little bits of resilience as well ... so it's understanding how those resilient pockets of the ecosystem persist through the bloom," he said. The federal government has thrown its support behind a state battling a massive, toxic algal bloom that has devastated the marine environment, but says the crisis cannot officially be declared a natural disaster. The bloom of the microalgae species karenia mikimotoi was identified off South Australia's Fleurieu Peninsula in March, and grew to more than 4400 sq km, close to the size of Kangaroo Island. It has been breaking up in recent weeks, spreading north into Spencer Gulf, south into the Coorong wetlands and along Adelaide's beaches in Gulf St Vincent into the Port River, killing tens of thousands of marine animals. Environment Minister Murray Watt said the bloom and its impacts were "incredibly disturbing", as he announced a $14 million federal funding package for the SA government. The money is likely to be used to pay for the clean-up of dead marine life from SA's beaches, support impacted businesses, bolster community awareness about the bloom and invest in science and research to better understand the incident. "There's no doubting whatsoever that this is a very serious environmental event facing South Australia," Mr Watt told reporters on Monday. "We are in uncharted waters here." Asked if the bloom and its impact should be declared a natural disaster, Mr Watt said it was not possible under the existing definition despite calls from scientists, the Greens and SA's Labor premier. A natural disaster declaration would trigger special federal assistance measures to support individuals, businesses and communities in their recovery. "We have managed outside the usual natural disaster framework to marshal the type of resources that South Australia has asked for," Mr Watt said. "One of the difficulties has been understanding exactly what its impacts are and what sort of response is required. "We won't solve this overnight and we are, to some extent, relying on weather conditions to help disperse the algal bloom." The algal bloom is naturally occurring, but the state's environment department has listed potential contributing factors including a marine heatwave that started in 2024, when sea temperatures were about 2.5C warmer than usual, combined with calm conditions. Another was the 2022/23 River Murray flood that washed extra nutrients into the sea followed by an unprecedented cold-water upwelling in the summer of 2023/24 that brought nutrient-rich water to the surface. Marine ecologist Dominic McAfee said the mortality in most heavily impacted areas was "extremely confronting". "It seems like almost everything has died," Dr McAfee, from the University of Adelaide's Environment Institute, told AAP. "We don't know how long it's going to go on, and so the impacts we're seeing now could just be the start of something more prolonged." Dr McAfee said it was hoped winter winds and swells would "disperse and nullify" the algae bloom, but it hadn't happened. "It seems to be more resilient than anticipated ... it's still at high fatal concentrations for a lot of marine life, and we're still seeing marine life wash up," he said. "And there's a chance that it will continue for many more months." Authorities previously said the algae had killed tens of thousands of marine animals from almost 450 species. Dr McAfee said it was the "tip of the iceberg" because the project monitoring the deaths only recorded species washed ashore, and it would not have accounted for smaller vertebrates and less well-known species. "There are little bits of resilience as well ... so it's understanding how those resilient pockets of the ecosystem persist through the bloom," he said.
Perth Now
5 days ago
- Perth Now
'Incredibly disturbing': federal help for algae crisis
The federal government has thrown its support behind a state battling a massive, toxic algal bloom that has devastated the marine environment, but says the crisis cannot officially be declared a natural disaster. The bloom of the microalgae species karenia mikimotoi was identified off South Australia's Fleurieu Peninsula in March, and grew to more than 4400 sq km, close to the size of Kangaroo Island. It has been breaking up in recent weeks, spreading north into Spencer Gulf, south into the Coorong wetlands and along Adelaide's beaches in Gulf St Vincent into the Port River, killing tens of thousands of marine animals. Environment Minister Murray Watt said the bloom and its impacts were "incredibly disturbing", as he announced a $14 million federal funding package for the SA government. The money is likely to be used to pay for the clean-up of dead marine life from SA's beaches, support impacted businesses, bolster community awareness about the bloom and invest in science and research to better understand the incident. "There's no doubting whatsoever that this is a very serious environmental event facing South Australia," Mr Watt told reporters on Monday. "We are in uncharted waters here." Asked if the bloom and its impact should be declared a natural disaster, Mr Watt said it was not possible under the existing definition despite calls from scientists, the Greens and SA's Labor premier. A natural disaster declaration would trigger special federal assistance measures to support individuals, businesses and communities in their recovery. "We have managed outside the usual natural disaster framework to marshal the type of resources that South Australia has asked for," Mr Watt said. "One of the difficulties has been understanding exactly what its impacts are and what sort of response is required. "We won't solve this overnight and we are, to some extent, relying on weather conditions to help disperse the algal bloom." The algal bloom is naturally occurring, but the state's environment department has listed potential contributing factors including a marine heatwave that started in 2024, when sea temperatures were about 2.5C warmer than usual, combined with calm conditions. Another was the 2022/23 River Murray flood that washed extra nutrients into the sea followed by an unprecedented cold-water upwelling in the summer of 2023/24 that brought nutrient-rich water to the surface. Marine ecologist Dominic McAfee said the mortality in most heavily impacted areas was "extremely confronting". "It seems like almost everything has died," Dr McAfee, from the University of Adelaide's Environment Institute, told AAP. "We don't know how long it's going to go on, and so the impacts we're seeing now could just be the start of something more prolonged." Dr McAfee said it was hoped winter winds and swells would "disperse and nullify" the algae bloom, but it hadn't happened. "It seems to be more resilient than anticipated ... it's still at high fatal concentrations for a lot of marine life, and we're still seeing marine life wash up," he said. "And there's a chance that it will continue for many more months." Authorities previously said the algae had killed tens of thousands of marine animals from almost 450 species. Dr McAfee said it was the "tip of the iceberg" because the project monitoring the deaths only recorded species washed ashore, and it would not have accounted for smaller vertebrates and less well-known species. "There are little bits of resilience as well ... so it's understanding how those resilient pockets of the ecosystem persist through the bloom," he said.
The Advertiser
08-07-2025
- The Advertiser
'Toxic to anything with gills': algal bloom spreading
A massive, toxic algal bloom that has killed thousands of fish, sharks and marine animals has spread to a capital city river. The bloom of the microalgae, karenia mikimotoi, was identified off South Australia's Fleurieu Peninsula in March, and grew to more than 4400 sq km, close to the size of Kangaroo Island. It has been breaking up in recent weeks, spreading north into Spencer Gulf, south into the Coorong wetlands and along Adelaide's beaches in Gulf St Vincent. SA Environment Minister Susan Close said the "devastating" bloom had now been detected in Adelaide's Port River. "Karenia mikimotoi has appeared in the Port River and is at reasonably high concentrations around Garden Island and Outer Harbour," she told reporters on Tuesday. "Nothing near like the concentrations that we saw at the beginning of this bloom ... but nonetheless elevated amounts." Ms Close said the algae had killed tens of thousands of marine animals from almost 400 species, and authorities were concerned some may be wiped out in the region. "Although not toxic to humans, it is toxic to anything with gills and anything that seeks to breathe underwater, and we have seen just the beginnings of the extent of the devastation that's occurred under the sea," she said. SA Primary Industries and Regional Development Minister Clare Scriven said the government had started talks with the Commonwealth about recovery assistance. It is not possible for the federal government to declare the incident a national disaster because the definition does not currently include algal blooms, she said. The SA government announced backdated licence fee relief for commercial fishers, aquaculture and charter boat operators impacted by the bloom. About $500,000 worth of fees will be waived to help operators, with a promise that more help will be available if needed. SA Professional Fishers Association chair Ben Barnes said some fishers reported seeing "absolute destruction of the environment" and the industry was yet to see the worst of the disaster. "It will be a recurring thing that we just won't know for the next five to six years," he said. "The extent of the devastation is unknown ... it will have an effect on larvae and eggs and production." Experts believe there are three potential contributing factors causing the bloom. One is a marine heatwave that started in September 2024, with sea temperatures about 2.5C warmer than usual, combined with calm conditions, light winds and small swells. Another is the 2022/23 River Murray flood that washed extra nutrients into the sea. That was followed by an unprecedented cold-water upwelling in summer of 2023/24 that brought nutrient-rich water to the surface. A massive, toxic algal bloom that has killed thousands of fish, sharks and marine animals has spread to a capital city river. The bloom of the microalgae, karenia mikimotoi, was identified off South Australia's Fleurieu Peninsula in March, and grew to more than 4400 sq km, close to the size of Kangaroo Island. It has been breaking up in recent weeks, spreading north into Spencer Gulf, south into the Coorong wetlands and along Adelaide's beaches in Gulf St Vincent. SA Environment Minister Susan Close said the "devastating" bloom had now been detected in Adelaide's Port River. "Karenia mikimotoi has appeared in the Port River and is at reasonably high concentrations around Garden Island and Outer Harbour," she told reporters on Tuesday. "Nothing near like the concentrations that we saw at the beginning of this bloom ... but nonetheless elevated amounts." Ms Close said the algae had killed tens of thousands of marine animals from almost 400 species, and authorities were concerned some may be wiped out in the region. "Although not toxic to humans, it is toxic to anything with gills and anything that seeks to breathe underwater, and we have seen just the beginnings of the extent of the devastation that's occurred under the sea," she said. SA Primary Industries and Regional Development Minister Clare Scriven said the government had started talks with the Commonwealth about recovery assistance. It is not possible for the federal government to declare the incident a national disaster because the definition does not currently include algal blooms, she said. The SA government announced backdated licence fee relief for commercial fishers, aquaculture and charter boat operators impacted by the bloom. About $500,000 worth of fees will be waived to help operators, with a promise that more help will be available if needed. SA Professional Fishers Association chair Ben Barnes said some fishers reported seeing "absolute destruction of the environment" and the industry was yet to see the worst of the disaster. "It will be a recurring thing that we just won't know for the next five to six years," he said. "The extent of the devastation is unknown ... it will have an effect on larvae and eggs and production." Experts believe there are three potential contributing factors causing the bloom. One is a marine heatwave that started in September 2024, with sea temperatures about 2.5C warmer than usual, combined with calm conditions, light winds and small swells. Another is the 2022/23 River Murray flood that washed extra nutrients into the sea. That was followed by an unprecedented cold-water upwelling in summer of 2023/24 that brought nutrient-rich water to the surface. A massive, toxic algal bloom that has killed thousands of fish, sharks and marine animals has spread to a capital city river. The bloom of the microalgae, karenia mikimotoi, was identified off South Australia's Fleurieu Peninsula in March, and grew to more than 4400 sq km, close to the size of Kangaroo Island. It has been breaking up in recent weeks, spreading north into Spencer Gulf, south into the Coorong wetlands and along Adelaide's beaches in Gulf St Vincent. SA Environment Minister Susan Close said the "devastating" bloom had now been detected in Adelaide's Port River. "Karenia mikimotoi has appeared in the Port River and is at reasonably high concentrations around Garden Island and Outer Harbour," she told reporters on Tuesday. "Nothing near like the concentrations that we saw at the beginning of this bloom ... but nonetheless elevated amounts." Ms Close said the algae had killed tens of thousands of marine animals from almost 400 species, and authorities were concerned some may be wiped out in the region. "Although not toxic to humans, it is toxic to anything with gills and anything that seeks to breathe underwater, and we have seen just the beginnings of the extent of the devastation that's occurred under the sea," she said. SA Primary Industries and Regional Development Minister Clare Scriven said the government had started talks with the Commonwealth about recovery assistance. It is not possible for the federal government to declare the incident a national disaster because the definition does not currently include algal blooms, she said. The SA government announced backdated licence fee relief for commercial fishers, aquaculture and charter boat operators impacted by the bloom. About $500,000 worth of fees will be waived to help operators, with a promise that more help will be available if needed. SA Professional Fishers Association chair Ben Barnes said some fishers reported seeing "absolute destruction of the environment" and the industry was yet to see the worst of the disaster. "It will be a recurring thing that we just won't know for the next five to six years," he said. "The extent of the devastation is unknown ... it will have an effect on larvae and eggs and production." Experts believe there are three potential contributing factors causing the bloom. One is a marine heatwave that started in September 2024, with sea temperatures about 2.5C warmer than usual, combined with calm conditions, light winds and small swells. Another is the 2022/23 River Murray flood that washed extra nutrients into the sea. That was followed by an unprecedented cold-water upwelling in summer of 2023/24 that brought nutrient-rich water to the surface. A massive, toxic algal bloom that has killed thousands of fish, sharks and marine animals has spread to a capital city river. The bloom of the microalgae, karenia mikimotoi, was identified off South Australia's Fleurieu Peninsula in March, and grew to more than 4400 sq km, close to the size of Kangaroo Island. It has been breaking up in recent weeks, spreading north into Spencer Gulf, south into the Coorong wetlands and along Adelaide's beaches in Gulf St Vincent. SA Environment Minister Susan Close said the "devastating" bloom had now been detected in Adelaide's Port River. "Karenia mikimotoi has appeared in the Port River and is at reasonably high concentrations around Garden Island and Outer Harbour," she told reporters on Tuesday. "Nothing near like the concentrations that we saw at the beginning of this bloom ... but nonetheless elevated amounts." Ms Close said the algae had killed tens of thousands of marine animals from almost 400 species, and authorities were concerned some may be wiped out in the region. "Although not toxic to humans, it is toxic to anything with gills and anything that seeks to breathe underwater, and we have seen just the beginnings of the extent of the devastation that's occurred under the sea," she said. SA Primary Industries and Regional Development Minister Clare Scriven said the government had started talks with the Commonwealth about recovery assistance. It is not possible for the federal government to declare the incident a national disaster because the definition does not currently include algal blooms, she said. The SA government announced backdated licence fee relief for commercial fishers, aquaculture and charter boat operators impacted by the bloom. About $500,000 worth of fees will be waived to help operators, with a promise that more help will be available if needed. SA Professional Fishers Association chair Ben Barnes said some fishers reported seeing "absolute destruction of the environment" and the industry was yet to see the worst of the disaster. "It will be a recurring thing that we just won't know for the next five to six years," he said. "The extent of the devastation is unknown ... it will have an effect on larvae and eggs and production." Experts believe there are three potential contributing factors causing the bloom. One is a marine heatwave that started in September 2024, with sea temperatures about 2.5C warmer than usual, combined with calm conditions, light winds and small swells. Another is the 2022/23 River Murray flood that washed extra nutrients into the sea. That was followed by an unprecedented cold-water upwelling in summer of 2023/24 that brought nutrient-rich water to the surface.
