Reef sharks population on the Australia’s Great Barrier Reef are in the catastrophic collapse. A new study by Australian scientists has revealed that reef sharks are facing ecological extinction.
According to a research conducted by William Robbins and colleagues at James Cook University and the Australian Research Council’s Center of Excellence for Coral Reef Studies – found grey reef shark numbers have declined to around 3 percent of unfished levels and are falling so quickly they could collapse to 1-1,000th of unfished levels within 20 years.
William Robbins said,
Reef sharks are effectively on a fast track to ‘ecological extinction’ – becoming so rare that they will no longer play their part in the ecology and food web of the reef.
Whitetip reef sharks have already fallen to 20 per cent of unfished levels, and are headed towards five per cent within two decades.
“These findings indicate that current management of no-take areas is inadequate for protecting reef sharks, even in one of the world’s most-well-managed reef ecosystems. Further steps are urgently required for protecting this critical functional group from ecological extinction,” wrote the team of researchers led by Dr. William D. Robbins.
The researchers also compared the shark numbers in reefs that had been zoned for the different levels of fishing and found that some type of no-take zones ‘pink-zones’ where one can not enter without permit virtually lead to no shark fishing. In contrast, shark numbers in ‘green zones’ that is prone to illegal fishing lead to rapid decline of sharks.
Mizue Hisano, a co-author of the study added, “Reef sharks mature late in life, and, like many whales and dolphins, produce very few offspring. This makes it hard for them to bounce back from even low levels of fishing, such as poaching in green zones.”
The Great Barrier Reef is the world’s largest coral reef i.e.1400 miles long. Higher sea temperatures and increasingly ocean acidity due to carbon dioxide emissions endangers the future of the reef. Commercial fishing is also increasingly threatening the existence of Sharks. It is estimated that every year 26 million to 73 million sharks are killed.
The study appears in this week’s issue of the journal Current Biology.