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The Age
3 days ago
- Health
- 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
3 days ago
- Health
- 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.'
Indian Express
14-05-2025
- Science
- Indian Express
Sharks, octopuses among 200 species killed by toxic algae in Australia
A toxic algae bloom off the coast of South Australia, which has been affecting the coastline since March, led to the killing of more than 200 marine species, including sharks and octopuses. The toxic algal bloom has now spread to about 150km on the coastline and nearly half (47%) of the dead species belonged to ray-finned fish while another 26% were sharks and rays, according to an analysis by OzFish, The Guardian reported. The algae responsible is called Karenia mikimotoi and it is reported to be like a toxic blanket which has smothered marine life, the OzFish South Australia project manager Brad Martin said. The algae produces poison which acts like a blanket above the water body and suffocates marine life, including fish, rays and sharks to death. 'It's an unprecedented event, because the bloom has continued to build and build,' wildlife scientist Vanessa Pirotta said, BBC reported. More than 200 marine species off the coast of South Australia (SA) have been killed by a weeks-long toxic algae explosion, in what conservationists have described as 'a horror movie for fish'. The algal bloom – a rapid increase in the population of algae in water systems -… — Rita Rosenfeld (@rheytah) May 13, 2025 Martin further explained that toxic algae can suffocate fish from their gills, cause haemorrhaging by attacking their red blood cells, and act as a neurotoxin which could attack the water creature's nervous system and cause unusual behaviour. 'This is why some fish and sharks are acting so strangely and why many of the dead have a red tinge, it is like a horror movie for fish,' Martin said. One of the causes of algal bloom identified by the state's environmental department is the ongoing marine heatwave, which has led to a rise in water temperature by 2.5 degree celsius. Since the density of algal bloom is large in nature, it effectively means that oxygen is being taken out of the water and hence the fishes are suffocating to death. This serious event has been documented with people sending and uploading pictures and videos of dead wildlife washed up on beaches. According to South Australia's environment minister, the outbreak has grown to an unprecedented magnitude. (with inputs from BBC, The Guardian)
The Independent
13-05-2025
- Health
- The Independent
Toxic algae bloom kills hundreds of marine species in Australia
A toxic algal bloom in South Australia has killed over 200 marine species, including deepwater sharks, octopuses and leafy sea dragons, in what conservationists have called one of the worst marine die-offs the region has ever seen. The algae, Karenia mikimotoi, has spread across more than 150km of coastline since it was first detected in March, nearly the size of the Kangaroo Island. Since the algae appeared, local people and scientists have observed mass deaths of fish, shellfish, sharks, sea dragons, rays, cuttlefish, and deepwater species along the southern coastline. South Australia 's environment minister said the outbreak had grown to an unprecedented scale. "It is a larger bloom than we have ever seen before," Susan Close said. Scientists say that it is being fuelled by an ongoing marine heatwave, with sea temperatures 2.5C above average, and calm conditions that allow it to thrive. Described as a 'toxic blanket', the bloom suffocates fish by damaging their gills and attacking red blood cells and the nervous system. It can lead to haemorrhaging and erratic behaviour in affected animals. 'It is like a horror movie for fish,' Brad Martin of OzFish told The Guardian. Ms Close said there was not much the government could do. "The only thing that is going to break this bloom up is a change in the weather and starting to get strong westerly winds," she said. An analysis of over 1,400 citizen science reports found around half of the dead species were ray-finned fish and more than a quarter were sharks and rays. Cephalopods like squid and cuttlefish and crustaceans such as crabs and lobsters were among the affected species as well. Though not toxic to humans, the algae has caused skin irritation and respiratory symptoms in some beachgoers. Authorities have temporarily closed several oyster farms and banned pipi harvesting in parts of South Australia. An alarm about the bloom was first sounded by beachgoers back in March after thick foam and dead marine animals washed up on Waitpinga and Parsons beach on the Fleurieu Peninsula. Professor Shauna Murray, a marine biologist at the University of Technology Sydney, identified the algae under a microscope and through DNA analysis. She told The Guardian that K mikimotoi was known to produce reactive oxygen that could suffocate marine life. South Australia's government said winds needed to disperse the algal bloom were being delayed by persistent high-pressure systems – another symptom of shifting climate patterns. Authorities say the full ecological and economic impact of the bloom is yet to be understood but environmental groups urge improved monitoring and stronger action on marine heatwaves, which are growing much more frequent as oceans continue to warm. Alongside the marine heatwave, southern Australia is suffering through one of the worst droughts on record. Ms Close sounded the alarm on how climate change was making the crisis worse. The minister said ocean monitoring showed 'a full-scale climate emergency in our coastal waters', with the bloom extending across an area roughly the size of Kangaroo Island and up to 20m deep. 'These extreme marine heat waves are not just anomalies, they are the new reality. And our marine ecosystems are the first casualties.'
Express Tribune
13-05-2025
- Health
- Express Tribune
South Australia hit by mass deaths of fish, sharks and octopuses due to toxic algae: Research says
Photo: Algal bloom become the reason for marine life death in South Australia Listen to article A toxic algal bloom stretching along South Australia's coastline since March has killed more than 200 marine species, including sharks, leafy sea dragons and octopuses, researchers said. The bloom, caused by the harmful algae "Karenia mikimotoi", has acted like a 'toxic blanket', suffocating marine life, said Brad Martin, South Australian project manager at OzFish, a conservation group. Analysis of more than 1,400 citizen scientist reports by OzFish found that 47% of the species killed were ray-finned fish, while 26% were sharks and rays. Cephalopods such as squid, cuttlefish and octopuses accounted for 7% of the casualties, while decapods – including crabs, lobsters and prawns – made up a further 6%. 'This type of bloom creates a low-oxygen environment, and marine animals simply cannot escape it,' Martin said. Karenia blooms are rare but deadly, releasing toxins and depleting oxygen levels in affected waters. Scientists say changing ocean conditions may be fuelling more frequent and severe outbreaks. Coastal communities and fisheries have reported widespread beach strandings, with some species never before seen in such numbers in die-offs. Local environmental groups have called for increased monitoring and long-term marine health strategies as ocean temperatures rise. 'It can choke fish by blocking their gills, trigger internal bleeding by damaging red blood cells, and act as a neurotoxin that disrupts the brain and nervous system, leading to erratic behaviour,' he said. 'That's why some fish and sharks have been behaving abnormally, and why many of the dead animals appear reddish – it's like a horror scene beneath the waves.' South Australia's environment department said the algal bloom is being fuelled by a prolonged marine heatwave, with sea temperatures around 2.5 degrees Celsius above average, combined with calm seas, low wind, and minimal swell. Though not harmful to humans, the algae can trigger skin irritation and respiratory issues, and has led to widespread marine deaths. First detected in mid-March off the Fleurieu Peninsula, the bloom has since spread to coastal areas across the state's south-east, including the Gulf St Vincent, Yorke Peninsula and Kangaroo Island, according to OzFish's Brad Martin. OzFish, a group focused on restoring aquatic ecosystems, expressed concern over the long-term consequences for fisheries, as the bloom has affected fish of all life stages – from juveniles to mature, breeding adults – along with their natural prey. South Australia's environment minister, Susan Close, said several oyster farms and commercial pipi harvesting operations had been suspended due to the outbreak, calling it an unprecedented event for the state. 'This is a major algal bloom with serious effects on marine species,' she said, adding that in some areas, the bloom has penetrated as deep as 20 metres. Professor Shauna Murray, a marine biologist at the University of Technology Sydney who identified the algae using microscopy and DNA analysis, said around 100 species of harmful algae are known globally, each with distinct toxic impact. Although not yet fully understood, Karenia mikimotoi is believed to release a reactive form of oxygen that damages fish gill cells, effectively suffocating them, said Professor Shauna Murray. The current bloom spans more than 150 kilometres along the coast, but it is not the largest recorded in Australia. In 2013, a different algal species, Alexandrium catenella, covered Tasmania's entire east coast, halting aquaculture and seafood operations for nearly four months, Murray added. Large-scale algal blooms can also reduce oxygen levels in the water, said Professor Martina Doblin, an oceanographer at the University of Technology Sydney who specialises in harmful algal events. Karenia mikimotoi is unusual, Doblin explained, in that it can draw energy from both sunlight and feeding on other organisms. This dual capability, combined with abnormally warm and stable ocean temperatures, has allowed the bloom to expand and persist over time. 'At low levels, it forms part of the natural food chain. But when it grows in large concentrations, it becomes a serious threat,' she said. Though rare, such blooms can have serious consequences for local economies. Doblin said better early warning and response systems could help minimise the impact of future outbreaks. A spokesperson for South Australia's environment department said strong westerly winds are needed to disperse the algae. However, the presence of ongoing high-pressure systems across southern Australia has delayed the arrival of those wind.
