24/03/2017

Ocean 'Tropicalisation' Radically Changing Southern Coastal Environments, Senate Inquiry Hears

ABC RuralDavid Claughton


Fears Tasmania's giant kelp forests almost extinct (ABC News)

Warming water moving south along the New South Wales and Western Australian coasts from their tropical north is leading to fisheries contamination, more frequent storms and the destruction of kelp forests, a Senate inquiry has heard.
The 'Current and future impacts of climate change on marine fisheries and biodiversity' inquiry has completed hearings in Sydney and Hobart, and is due to report by June 30.
Senators heard that fishermen have registered warm ocean currents making their way down the NSW coast, bringing fish contaminated with toxins such as ciguatera.
The toxin is only present in larger Spanish mackerel, which led to a food poisoning outbreak and subsequent ban on the larger fish at the Sydney Fish Market.
"Three people off Evans Head got ciguatera so we've had to stop catching large mackerel and the fish market won't take any ... over 10 kilograms," said Tricia Beattie, the chief executive of the Professional Fishermen's Association.
The inquiry also heard that coral fish are migrating much further south on the warmer currents leading to radical change in the underwater environment.
The migrating fish are eating plant life, including kelp, which underpins major fisheries in southern waters.
In Tasmania, kelp forests have almost disappeared due to rapidly warming waters and the spread of sea urchins.
Adriana Verges of the University of NSW said the tropical fish are destroying seaweed beds all along the east and west coasts of Australia, affecting key industries based on lobster and abalone stocks.
"It's the seaweeds that provide the habitat," she says.
"They can overgraze them and that causes a profound shift, whereby the entire ecological community changes and that's already been shown in northern NSW and the west coast of Australia."
Rabbitfish feed on kelp, filmed by researchers investigating its disappearance in southern oceans. (Supplied: Adriana Verges)
One kelp species has already been listed for protection, but researchers want more to be protected.
Professor David Booth from the Centre for Environmental Sustainability at University of Technology Sydney singled out the need for more resources to protect the ocean environment in places like the 2,900 square kilometre Perth Canyon on the west coast.
"I don't think we have enough data on what is actually in some of these areas and we're flying blind with a lot of the management," he said.
Cameras on the sea floor recorded migrating coral fish feeding where kelp has disappeared. (Supplied: Enric Ballesteros)
While Professor Booth said the oceans can not be climate proofed, he said they could be made climate ready, including the addition of additional marine sanctuaries in Commonwealth and northern trawl fishery waters.
Fishermen are opposed to an increase of ocean sanctuaries arguing that the industry has suffered too many cuts in recent years, and pollution and the causes of climate change itself need to be dealt with first.

'Slapped' by twin bleaching events
The coral bleaching of the Great Barrier Reef was happening more frequently, Professor Booth told the inquiry, occurring in 1998, 2004, 2006, 2011 and the past two years.
"Two bleaching events in a row, that's devastating," he said.
"It's like being slapped twice and not having a chance to recover.
"You can see there's a bit of a gap between them, but now we're now talking 2016-17 and if we get 2018 as well ... uncharted waters is a good way to put it."
NSW fishermen have also registered more frequent storms, the latest in January damaging processing facilities, retail outlets and slipways on the state's north coast.
Ms Beattie said the Wallis Lake Cooperative suffered a lot of damage.
"They lost their roofs, they lost their slipway ... pipes were broken, it was like a small hurricane had gone through the area," she said.

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