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| Tasmania marine heatwave hits seafood industry and puts some species at risk | Tasmania marine heatwave hits seafood industry and puts some species at risk |
| (4 months later) | |
| Ocean temperatures off the coast of Tasmania have risen to 4.5C above average – twice the temperature rise that led to the mass coral bleaching of the Great Barrier Reef – in a marine heatwave that has lasted more than 130 days. | Ocean temperatures off the coast of Tasmania have risen to 4.5C above average – twice the temperature rise that led to the mass coral bleaching of the Great Barrier Reef – in a marine heatwave that has lasted more than 130 days. |
| The above-average temperatures were first recorded in December and have continued into April, affecting the oyster, salmon and abalone industries, as well as stressing already declining kelp forests. | The above-average temperatures were first recorded in December and have continued into April, affecting the oyster, salmon and abalone industries, as well as stressing already declining kelp forests. |
| Dr Alistair Hobday, a senior principal research scientist with the CSIRO in Tasmania, said the heatwave could be attributed to El Niño, which extends the southern tip of the East Australian Current down to Tasmania, bringing warmer waters with it, and the effects of climate change. | Dr Alistair Hobday, a senior principal research scientist with the CSIRO in Tasmania, said the heatwave could be attributed to El Niño, which extends the southern tip of the East Australian Current down to Tasmania, bringing warmer waters with it, and the effects of climate change. |
| “Part of the warming we just can’t explain as being down to something other than global warming,” Hobday told Guardian Australia. “In about four months – we are doing that work now – we will be able to say that 60% of it is due to climate change and 40% is due to El Niño.” | “Part of the warming we just can’t explain as being down to something other than global warming,” Hobday told Guardian Australia. “In about four months – we are doing that work now – we will be able to say that 60% of it is due to climate change and 40% is due to El Niño.” |
| While the heatwave’s visual impacts were “not as dramatic as the bleaching of the coral reef”, Hobday said it had contributed to the mass death of oysters from Pacific Oyster mortality syndrome (Poms), which had never been reported in the state before devastating Tasmanian oyster farms this summer. | While the heatwave’s visual impacts were “not as dramatic as the bleaching of the coral reef”, Hobday said it had contributed to the mass death of oysters from Pacific Oyster mortality syndrome (Poms), which had never been reported in the state before devastating Tasmanian oyster farms this summer. |
| The higher temperatures were also linked to abalone deaths and a decline in the salmon harvest. | The higher temperatures were also linked to abalone deaths and a decline in the salmon harvest. |
| The effect of the heatwave on local marine species is still being studied, but Hobday said some species, such as the giant kelp forests on the east coast, which have declined by more than 90% in the past 40 years, were already suffering the effects of longer-term warming. Other species have been slowly shifting south. | The effect of the heatwave on local marine species is still being studied, but Hobday said some species, such as the giant kelp forests on the east coast, which have declined by more than 90% in the past 40 years, were already suffering the effects of longer-term warming. Other species have been slowly shifting south. |
| “It’s the same as when Tasmanian people go to Queensland for a holiday: they can’t stand the heat and humidity, yet Queenslanders who have lived there for some time cope with it fine,” Hobday said. | “It’s the same as when Tasmanian people go to Queensland for a holiday: they can’t stand the heat and humidity, yet Queenslanders who have lived there for some time cope with it fine,” Hobday said. |
| Ocean temperatures off Tasmania have increased by 2C in the past 100 years, three times the global average ocean temperature rise, and the island sits within a recognised global warming hot spot. | Ocean temperatures off Tasmania have increased by 2C in the past 100 years, three times the global average ocean temperature rise, and the island sits within a recognised global warming hot spot. |
| Hobday said the heatwave provided scientists and aquaculture businesses with “a glimpse of the future”. | Hobday said the heatwave provided scientists and aquaculture businesses with “a glimpse of the future”. |
| “People who are involved in ocean businesses are going to have to say, ‘look, if this is what it’s going to be like, we should learn about how to adapt’,” he said. “You just should not ignore a look in the crystal ball.” | “People who are involved in ocean businesses are going to have to say, ‘look, if this is what it’s going to be like, we should learn about how to adapt’,” he said. “You just should not ignore a look in the crystal ball.” |
| Data collected through public reports on RedMap.org.au, a project led by the University of Tasmania’s Institute for Marine and Antarctic Studies (IMAS), have shown an increase in species such as snapper and yellowtail kingfish, which were previously seen in very low numbers in Tasmanian waters. The yellow-bellied sea snake, from the south coast of New South Wales, and jimble jellyfish, usually found only on the north coast of Australia, from Western Australia to Southern Queensland, have also been sighted. | Data collected through public reports on RedMap.org.au, a project led by the University of Tasmania’s Institute for Marine and Antarctic Studies (IMAS), have shown an increase in species such as snapper and yellowtail kingfish, which were previously seen in very low numbers in Tasmanian waters. The yellow-bellied sea snake, from the south coast of New South Wales, and jimble jellyfish, usually found only on the north coast of Australia, from Western Australia to Southern Queensland, have also been sighted. |
| “We are seeing species move – the problem is that different species can do that at different rates,” the University of Tasmania’s associate professor Gretta Pecl, who helps run the project, told Guardian Australia. | “We are seeing species move – the problem is that different species can do that at different rates,” the University of Tasmania’s associate professor Gretta Pecl, who helps run the project, told Guardian Australia. |
| “It’s causing these large differences in our ecosystems. The clearest example of that in Tasmania is the long-spined sea urchin, which is moving down the east coast... eating all the kelp forests and leaving behind these rocky urchin barrens that rock lobsters and other organisms don’t like to live in,” she said. “The larvae can survive at 12 degrees, so as our winter temperatures hit that 12 degree threshold now, it’s allowing more and more of them to survive.” | “It’s causing these large differences in our ecosystems. The clearest example of that in Tasmania is the long-spined sea urchin, which is moving down the east coast... eating all the kelp forests and leaving behind these rocky urchin barrens that rock lobsters and other organisms don’t like to live in,” she said. “The larvae can survive at 12 degrees, so as our winter temperatures hit that 12 degree threshold now, it’s allowing more and more of them to survive.” |
| Professor Philip Boyd, with IMAS, said species that preferred cooler waters were at risk of extinction if they could not migrate or adapt in time, or, as the higher temperatures extended south, were left with nowhere to go. | Professor Philip Boyd, with IMAS, said species that preferred cooler waters were at risk of extinction if they could not migrate or adapt in time, or, as the higher temperatures extended south, were left with nowhere to go. |
| “As you get to the southern extremity of Tasmania, you can’t just keep having these kelp forests, because you run out of coastline and end up in deeper water,” Boyd said. “It’s already undermining the whole ecosystem that’s there.” | “As you get to the southern extremity of Tasmania, you can’t just keep having these kelp forests, because you run out of coastline and end up in deeper water,” Boyd said. “It’s already undermining the whole ecosystem that’s there.” |