‘A dead shark, dead rays, dead fish, dead cuttlefish': The toxic algal bloom is spreading
An outbreak of the microalgae, Karenia mikimotoi, has sucked all the oxygen from the water, killing fish, marine mammals, invertebrates, seaweed and sea grasses.
Great Southern Reef Foundation co-founder Stefan Andrews said great swaths of the ocean are giant dead zones with neon-green water and floating carcasses, with at least 450 marine species affected in the past month, according to citizen science reports.
'What's really disturbing when you're underwater is you see all these fish and everything that have died on the bottom, but there are no decomposers, no crabs and molluscs that usually you would find on dead fish carcasses eating away and recycling those nutrients,' Andrews said.
'There's just this gross, slimy mould, a sort of slime, that's forming over those fish and the algae itself will feed on, engulfing the decomposing fish that have already suffered and died from the algae bloom, so it's further fuelling itself through the dead things, which just really shocking to see.'
In March, Andrews started hearing reports from friends on the Fleurieu Peninsula of rare fish washing up on the beach, and there were credible reports the algal bloom extended as far south as the Victorian border. By early July it stretched into urban areas around Adelaide and into the Spencer Gulf, and Andrews said there were fears it could disrupt the winter cuttlefish aggregation for winter egg laying near Whyalla.
'There was a lot of hope that as water temperature would drop, then that would stop the harmful algal bloom spreading, but that hasn't been the case,' Andrews said. 'They were also saying storms might break it up but hasn't been the case. The water doesn't get any colder now, so the experts are predicting it's not going away this winter and might be around for some time.'
Environment Minister Murray Watt has said the event was occurring only in state waters, but the federal government would consider a request for assistance from the state government. He is in Adelaide but an announcement is yet to be made.
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The Age
2 days ago
- The Age
‘Cyclone underwater': Why the algae disaster could hit Australia's east coast
The harmful algal bloom devastating marine ecosystems off the coast of South Australia is the largest of its kind ever recorded in Australia and could easily occur on the east coast, experts warn. On Tuesday, the South Australian government announced it will match funding promised by the federal government, bringing the total package to deal with the deadly Karenia mikimotoi outbreak to $28 million. The outbreak of the toxic microalgae was first discovered in March on the Fleurieu Peninsula, and has since spread to the Yorke Peninsula, Kangaroo Island, Gulf Saint Vincent and Spencer Gulf. Beachgoers and scientists have documented a vast array of sea creatures washing up dead on beaches. An online citizen science project has identified 450 species killed by the bloom, with the most affected being Southern Fiddler rays. 'It's the biggest bloom of Karenia mikimotoi we've experienced in Australia, but [not] anywhere in the world,' said Professor Shauna Murray, a marine biologist at the University of Technology Sydney. 'There have been larger blooms of Karenia mikimotoi in northern China – it's been very problematic there.' What caused the toxic algal bloom in South Australia? SA Premier Peter Malinauskas said three factors had contributed to the deadly outbreak. The 2022-23 Murray River floods, the biggest since 1956, had forced the largest volume of nutrients from the Murray-Darling system into the marine environment for 70 years.
Sydney Morning Herald
2 days ago
- Sydney Morning Herald
‘Cyclone underwater': Why the algae disaster could hit Australia's east coast
Second, during the following summer, a longer-than-ever Bonney Upwelling – the natural phenomenon in South Australia that brings up nutrient-rich water from deepwater to the surface – was recorded. Loading Finally, the ongoing marine heatwave means the waters around South Australia have been 2.5 degrees hotter than usual since last year. 'That allowed the algae, that was always there, to explode in its volume,' Malinauskus told reporters on Tuesday. 'It is reasonable to assume that we will see other events of this nature elsewhere in the country and other parts of the world.' Could it happen on Sydney or Melbourne coastlines? Murray said this was not only possible but 'quite likely', given it has already happened in the eastern states on a smaller scale. Murray said previous outbreaks of Karenia mikimotoi in NSW and Victoria, as well as other harmful algal blooms, had affected fishing and aquaculture by making fish unsafe to eat. 'In terms of water column conditions and how similar it would be on the [east] coast, we have upwelling events ... we've had marine heatwaves, we've had all of those things,' Murray said. Loading Can anything be done to fix the algal bloom? The SA government has said 'nothing can be done naturally to dilute or dissipate the bloom'. Murray said Korea and Japan had decades of experience dealing with harmful algal blooms affecting aquaculture facilities, and had researched several strategies, including sprinkling clay into the water to sink the algae. Yet this had not been studied in the Australian environment. 'We simply don't have any data to back up whether any of those methods would work, and most importantly, whether or not they would actually cause additional damage to the marine environment,' she said. How is it harmful to marine life? Karenia mikimotoi has choked ecosystems of oxygen, killing everything from bivalves, worms and cuttlefish to sharks, rays and dolphins. 'It's similar in effect to a cyclone underwater,' Murray said. Marine scientist Janine Baker from the Great Southern Reef Foundation said there would be long-term and widespread environmental, social and economic impacts. 'It's dreadful – I've never seen anything like this in the 35 years I've been working in the marine environment,' Baker said. 'What concerns me is that because there are so many vacant niches now, it will promote the settlement of opportunistic and potentially invasive species.' She said there were already introduced species from overseas and eastern Australia – such as long-spined sea urchins – and the problem was increasing with warming southern oceans. Why won't the federal government declare it a national disaster? Federal Environment and Water Minister Murray Watt has said the Commonwealth Natural Disaster Framework was designed for events such as bushfires and cyclones, and the algal bloom did not fit the bill. He argued the point of declaring a natural disaster was to unlock funding, and this was moot because he obtained $14 million in federal assistance anyway. Dr Scott Bennett from University of Tasmania's Institute for Marine and Antarctic Studies said the government should treat the bloom as a natural disaster. 'The federal government needs to not treat this as an isolated event or a localised event – this is symptomatic of a broader national issue,' Bennett said. 'We're seeing more intense and more frequent marine heatwaves occurring around the country.' What scientific research needs to happen? Loading The SA government said the $28 million package will include beach clean-up, assistance for affected businesses and $13.5 million earmarked for science and monitoring. That includes $8.5 million for a coastal monitoring network, $3 million for rapid assessment of fish stocks using remote underwater video surveys and dive surveys, and $2 million for a new national testing laboratory in South Australia for harmful algal bloom and brevetoxin/biotoxin testing. (At present, samples are sent to New Zealand for analysis.) The catastrophe is affecting the Great Southern Reef, a rocky reef rich in biodiversity that extends from NSW, around the southern side of the continent and up the coast of Western Australia. Bennett and other research partners in the Great Southern Reef Foundation have called for $40 million over 10 years for baseline research into the reef. However, Bennett acknowledged the research focus needed to be on South Australia right now, first diagnosing the extent of the problem and then focusing on key habitat recovery. Fortunately, the state already had experience restoring kelp forests, seagrass meadows and oyster reefs damaged by run-off, he said. 'They've got a really strong track record in large-scale habitat restoration.'
Sydney Morning Herald
3 days ago
- Sydney Morning Herald
‘A dead shark, dead rays, dead fish, dead cuttlefish': The toxic algal bloom is spreading
The toxic algal bloom that has killed sharks, rays, fish, dolphins and seals along thousands of kilometres of South Australian coastline is now in its fourth month with no sign of abating, as pressure mounts on the federal government to declare a national disaster. An outbreak of the microalgae, Karenia mikimotoi, has sucked all the oxygen from the water, killing fish, marine mammals, invertebrates, seaweed and sea grasses. Great Southern Reef Foundation co-founder Stefan Andrews said great swaths of the ocean are giant dead zones with neon-green water and floating carcasses, with at least 450 marine species affected in the past month, according to citizen science reports. 'What's really disturbing when you're underwater is you see all these fish and everything that have died on the bottom, but there are no decomposers, no crabs and molluscs that usually you would find on dead fish carcasses eating away and recycling those nutrients,' Andrews said. 'There's just this gross, slimy mould, a sort of slime, that's forming over those fish and the algae itself will feed on, engulfing the decomposing fish that have already suffered and died from the algae bloom, so it's further fuelling itself through the dead things, which just really shocking to see.' In March, Andrews started hearing reports from friends on the Fleurieu Peninsula of rare fish washing up on the beach, and there were credible reports the algal bloom extended as far south as the Victorian border. By early July it stretched into urban areas around Adelaide and into the Spencer Gulf, and Andrews said there were fears it could disrupt the winter cuttlefish aggregation for winter egg laying near Whyalla. 'There was a lot of hope that as water temperature would drop, then that would stop the harmful algal bloom spreading, but that hasn't been the case,' Andrews said. 'They were also saying storms might break it up but hasn't been the case. The water doesn't get any colder now, so the experts are predicting it's not going away this winter and might be around for some time.' Environment Minister Murray Watt has said the event was occurring only in state waters, but the federal government would consider a request for assistance from the state government. He is in Adelaide but an announcement is yet to be made.
