Tourists, anglers blamed as shark population plummets
The cry of ‘‘shark’’ can clear the shallows of any Australian beach in minutes as swimmers scramble for safety all too aware of a steep rise in attacks over the past decade.
Despite the danger to humans, however, shark populations off Australia’s east coast have fallen dramatically over the past decades, a study suggests, leading researchers to conclude that human predation is most probably to blame.
They looked at the number of sharks caught off Queensland in a scheme set up in 1955 to deter attacks and found that the number of great whites and hammerheads had fallen by 92 per cent in that time, while the catch rate for tiger sharks had fallen by 74 per cent over the past 25 years.
They found that those left were getting smaller. Over the past 20 years the average size of great hammerheads, the largest variety of hammerhead, had dropped 22 per cent to 2.1m. Tiger sharks had shrunk by 21 per cent to an average 2.1m. Whaler sharks, including the bronze whaler, had shrunk 9 per cent over the past 50 years, to 1.7m. The study, by the University of Queensland and Griffith University, supports claims by some scientists and conservationists that a surge in attacks in parts of Australia is more probably a result of the rising human population than any increase in shark numbers.
When Joel Mason, 36, was mauled by a shark north of Sydney last weekend he became the ninth victim in 71 days off the coast of Australia. He survived but it reignited calls for a cull.
A study in 2016 showed the number of attacks had risen from an average of 6.5 a year in 1990-2000 to 15 a year over the past decade. So far this year there have been 18 serious shark attacks in Australia, one fatal. The study argued that the rising number of attacks coincided with an increasing human population, more people visiting beaches, a rise in the popularity of water-based fitness and recreational activities, and people accessing previously isolated coastal areas. The study said that the rate and magnitude of decline in shark numbers ‘‘strongly implicate fishing as the primary cause’’.
The Queensland control programme now spans more than 1700km of Australian coastline and has caught nearly 50,000 sharks over the past 55 years in nets or on baited lines.
Global catches of sharks and rays increased from about 272,000 tonnes in 1950 to 828,000 tonnes in 2000. Australia is home to more than a quarter of the world’s sharks and rays.
India was the world leader in shark and ray fishing followed by Indonesia, Pakistan, the US, Taiwan, Mexico and Japan. Trends such as shark-fin soup in Asian restaurants pushed profits from fishing up, with dried shark fin costing several hundred dollars a kilogram. – Fairfax