9 July 2007The AustralianEwin Hannan
CLIMATE change is likely to put significant pressure on the nation's fish stocks, with new CSIRO research identifying the eastern and southeast coastlines as the most vulnerable to warming temperatures.
A new CSIRO climate change vulnerability index, to be launched today, finds coastal waters will warm by up to two degrees by 2030, encouraging fish to move south, threatening marine turtles, and potentially pushing box jellyfish down the east coast.
Scientists said yesterday fishing stocks potentially faced a "double whammy" from the consequences of fishing and climate change.
The climate change index, developed by CSIRO's Marine and Atmospheric Research Unit, considered seven large marine domains around Australia and determined their vulnerability to climate change based on five dimensions.
These were biological, regional characteristics, climate change, fishing, and other stress factors caused by human activity.
The index revealed that the eastern-central and southeast domains were the most vulnerable to the impact of climate change.
The index predicts that sea surface temperatures around Australia will warm by 1-2C by 2030, and by up to 3C by 2070, with the greatest warming off southeastern Australia and the Tasman Sea.
Anthony Richardson, a member of the CSIRO's Wealth from Oceans Flagship, said the advantage of the index was that it identified principal stress factors for each domain, and allowed the development of regional policies to tackle climate change.
Dr Richardson said that as waters warmed along the east coast, fish and marine life would be encouraged to move south.
He said scientists believed potentially fatal box jellyfish could move south from Queensland.
"The east Australian current which flows south along the east coast will strengthen and take jellyfish further south," he said. "The conditions there will be warmer so they may do OK further south so that has implications for bathing."
Dr Richardson said the impact of climate change would have potential significant consequences for the nation's fishing industry, with warm-water fish likely to move south, and cold-water fish also expected to retreat down the coast.
"I think the fishing industry is starting to be concerned about the impact of climate change," he said. "They are fishing heavily, and the changing environmental considerations are all stresses in the future. Pressure from fishing and climate change represent a double whammy for the industry."
Professional fisherman Rolf Norington has already seen a change in the species he catches over his 25 years in the industry.
Now licensed to catch only prawns and squid, Mr Norington, from Brooklyn, north of Sydney, said that warmer currents sweeping down the coast from Queensland had brought the spawn of new species into Broken Bay.
"With the 13 years of drought we have just faced, the Hawkesbury River system has had little flow and the saltiness of the water has allowed new species to grow and breed," he said as he prepared his boat, Australia Star, for this week's work.
"If we are allowed to address the problems caused by drought and climate change, it will be nice, but we are being regulated out of existence and our markets are being taken by imported prawns and other seafood."
Mr Norington said the existing conditions placed on prawntrawlers prevented them from taking any fish species with amateur fishing bag limits and also prevented them from working on weekends and public holidays.
"We are always painted as the bad guys ... raping the fishing resource, but nothing could be further from the truth," he said.
"It is our livelihood. Why would we destroy it?"
Mr Norington, 41, said he and other professional fishermen were keen to work with government bodies and environmentalists to ensue that Australians could continue to enjoy fresh local seafood and not rely on frozen produce brought in from Asia.
According to the CSIRO, the warming waters will also result in an increased number of female marine turtles being born, making it more difficult for the turtles to mate in the future.
The index will be presented to the Australian Marine Science Association conference starting in Melbourne today. The conference will also consider research examining the impact of warming waters on climate change.
The CSIRO's Elvira Poloczanska said fish on the east coast that were living on or near the sea bed had shifted southwards as coastal waters warmed.
"The large giant kelp forests that are found fringing the coasts at spots in southern Australia support a myriad of fish and other animals," she said. "These cold-water seaweeds are at high risk in Australia from warming waters. Kelp forests on the east Tasmanian coast are already in decline as sea temperatures increase."
Additional reporting: D.D. McNicoll
