Decrease in shark numbers poses risk to Great Barrier Reef: researcher
Wednesday, January 11, 2012
© The Cairns Post
THE Far North's reef shark populations are dropping at an alarming rate and a marine biologist says the decline of the apex predators could pose a serious risk to the ecology of the Great Barrier Reef.
Research has found that reef shark populations are decreasing by up to 17 per cent each year, Dr Ashley Frisch, of James Cook University’s ARC Centre of Excellence for Coral Reef Studies, says.
"There is little doubt shark and fish populations are under threat from fishing, climate change and other impacts, so it’s critically important that we understand the role of high-level predators in maintaining healthy coral reefs," Dr Frisch said.
"Before we exploit a species we should find out what the consequences are.
"We usually wait until we’ve depleted them before we understand how important they are and then it’s too late."
Adam O’Malley, a spokesman for Cairns tour operator Passions of Paradise, said maintaining healthy reef shark populations in the Far North was also important for the tourism industry.
"The excitement our passengers experience when they see their first shark on the Great Barrier Reef is incredible,’’ he said.
"We want to make sure future generations have the opportunity to see these magnificent creatures up close in their natural environment.
"For many of the passengers who travel on Passions of Paradise they are on the top of their list of things to see," Mr O’Malley said.
In April, Dr Frisch will embark on a three-year research project to determine the ecological value of sharks to the Great Barrier Reef.
Sharks could be valuable keystone predators, which regulate the abundance of other organisms, such as the lions of the Serengeti or the wolves of Yellowstone National Park he said.
However, this phenomenon is yet to be investigated on coral reefs.
Dr Frisch’s research will focus on three predominant species near Lizard Island, off the coast of Cooktown – grey, white-tipped and black-tipped reef sharks.
Dr David Wachenfeld, chief scientist at the Great Barrier Reef Marine Park Authority, agreed there was "robust scientific evidence" that some species of reef shark were in decline.
"It’s extremely important research that will be important to future marine park management," he said about Dr Frisch’s study.
"We need to keep working with fisheries and fishers to make sure that their fishing is sustainable."
Fisheries Queensland principal scientist Malcolm Dunning said the department was managing shark populations more sustainably than ever after limiting catches in 2009.