Global warming driving Australian fish south-report
By Michael Byrnes (Reuters) - April 4, 2007
Global warming is starting to have a significant impact on Australian marine life, driving fish and seabirds south and threatening coral reefs, Australia’s premier science organisation said on Wednesday.
But much more severe impacts could occur in coming decades, affecting sea life, fishing communities and tourism.
In particular, warmer oceans, changes in currents, disruption of reproductive cycles and mass migration of species would affect Australia’s marine life, particularly in the southeast.
Already, nesting sea turtles, yellow-fin tuna, dugongs and stinging jellyfish are examples of marine life moving south as seas warm, said the report by the government-backed Commonwealth Scientific and Industrial Research Organisation.
“It’s not a disaster for the ones that can move south. It is for the ones that can’t move south,” lead author of the report, Dr Alistair Hobday, told Reuters.
“If you’re at the tip of Tasmania, you’ve got nowhere else to go,” he said, referring to Australia’s southern island state, the last major part of Australia before the Antarctic.
Atlantic salmon, which are farmed in Tasmania, face a bleak future. Salmon farming businesses would become largely unviable as the ocean warmed the predicted one to two degrees over the next 30 years, Hobday said.
Fisheries and aquaculture are worth more than A$2.5 billion a year the report, “Impacts of Climate Change on Australian Marine Life”, says. It is the first major study in the Australian region to combine the research of climate modellers, ecologists and fisheries and aquaculture scientists.
Coral in the Great Barrier Reef off Australia’s northeast may be hit by more frequent bleaching events, every two or three years compared with five or six years at present.
“You would basically get hit with a hammer every couple of years. Nobody responds well to that,” Hobday said.
Worse, oceans are becoming more acidic as carbon dioxide levels continue to rise in the atmosphere. This will adversely affect many organisms that use calcium carbonate for their skeletons and shells, including corals and molluscs.
TURTLES UNDER THREAT
Turtles are especially vulnerable to warming, with warm weather causing increased female hatchlings, the report said.
Changing ocean food production because of warming could also affect other species already battling low numbers by restricting their food supply, the CSIRO report, which was prepared for the Australian government, said.
Its release comes two days before the U.N. Intergovernmental Panel on Climate Change adopts a major report on the impacts of global warming.
Australia’s southeast will be hit hardest, with the Tasman Sea suffering the greatest ocean warming in the southern hemisphere, the CSIRO report, citing the U.N. climate panel, said.
The result is likely to be a decline in fish along Australia’s eastern seaboard.
“These species have become adapted to a particular set of conditions and the speed at which the ocean is changing is faster than they have experienced,” Hobday said.
One result would be that Australian fishing industries would have to move south.
Tourism was also likely to be hard hit, the report said, highlighting the multi-billion dollar economic value of the nation’s reefs.
An expected increase in human migration to the Australian coast over the next 10-20 years because of warming temperatures would also add to pressure on the oceans, Hobday said.
This would be accompanied by rising sea-levels that would likely lead to greater coastal erosion.
“You’ll have cliff-side mansions crashing into the ocean,” he said, adding that Australia needed to reduce its greenhouse gases and pollution and to better protect coastal areas.