3 days ago
- Science
- Sydney Morning Herald
Great whites sharks: maybe they won't need a bigger boat
As media around world mark the 50th anniversary of the film Jaws, the film that turned great whites into a public enemy, research funded by the NSW Department of Primary Industries Shark Management Strategy and Deakin University suggests the species is in trouble and that fewer than 500 adult breeding sharks were found around Australia's coastline.
The finding challenges fears that their numbers are mounting. Such claims have been widespread since Steven Spielberg's horror classic opened and provided a lucrative living for many, like Queensland sideshow alley shark hunter Vic Hislop, to catch, kill and display the species. But great whites fuel our beach culture's deepest fear, and until now, exact numbers have evaded reality.
However, the groundbreaking research indicates a relatively small adult breeding population. Scientists who have mapped the DNA of captured 650 great whites have identified 275 full siblings and 511 half siblings among great whites off the east coast and 12 full-sibling relationships and 29 half siblings in the southern oceans.
Small numbers aside, the major surprise was that sharks along the east coast and southern Australian waters were closely related and migratory.
Some 2.8 people have died in the annual average of 20 shark attacks in Australian waters over the past decade. Shark terror has especially touched NSW, Western Australia and South Australia. Everybody has a theory, ranging from 'sharks are back because nobody is killing whales' to 'the depletion of fish stocks by long-line fishers has them cruising the continental shelf searching for food'.
The researchers said that despite there being fewer than 500 breeding great whites, interactions could be increasing due to the fact more people are entering the water to surf, or to fish with hooks or spears. 'Conservation management of white sharks in Australia is complicated by increasing frequencies of human-shark interactions, sometimes resulting in human casualties, leading to public demands for shark control and culling programs,' the study says.
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The findings on Australia's great white numbers are likely to refuel the debate about shark netting. Exactly a century after 12-year-old Alfred Australia Howe became the first European to die in a shark attack in the colony of NSW, meshing was adopted by NSW Fisheries on January 31, 1937, following more than a decade of deaths off Sydney beaches.
Nearly 90 years later, a growing contingent says the nets have little impact in preventing interactions between sharks and swimmers.
