SYDNEY, Sept. 11 (Xinhua) -- New research from two Australian universities on Wednesday has revealed that tiger shark numbers have declined 71 percent on the Queensland State coast.
"This has been particularly rapid in southern regions which is unusual," lead author Dr. Chris Brown from the Griffith University Australian Rivers Institute said.
Coming as a surprise to researchers and the wider community, the tiger shark-tracking data follows a recent spate of attacks on the Great Barrier Reef.
According to Taronga Zoo's Shark Attack File, Since 2017 there's been a total 10 shark attacks in the state, with one proving fatal.
While it's not known how many attacks were the result of tiger sharks, the species are notoriously aggressive in the area and suspected to be responsible for a large number of the incidents.
"Tiger sharks are top predators that have few natural enemies, so the cause of the decline is likely overfishing."
"This decline is surprising, because tiger sharks are one of the most resilient large shark species. Mothers can birth up to 70 pups every three years, which means the population should be resilient to moderate levels of fishing."
Although Australia has some of the strictest regulations in the world when it comes to shark protection, co-author of the study Dr. George Roff from the University of Queensland said recent satellite studies that followed tiger sharks found that the East Coast of Australia is a "risk hotspot for tiger sharks" due to the number of commercial long-line fisheries.
"We were also surprised to learn that the decline has been stronger in southern Queensland, when compared to tropical waters," he said.
"Tiger sharks are a tropical species and are expected to move further south with long-term warming of the East Coast of Australia."