Global warming to fry Australian  fish stocks*

By Ewin Hannan

July 09, 2007 06:32am
Article from: The Australian

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."