It should seem that sharks are used to bad news by now.
Since Western Australia's (WA) shark cull began in January 2014, the Internet has been haunted with images of pale shark corpses hooked and dangling from baited drumlines. WA's recent "shark control" measures aim to protect its beachgoers from deadly encounters, but its bloody, no-sharks-no-problem methods have left many around the world enraged.
Opponents of the cull are used to wimpy zero-sum explanations, like the popular refrain "It's them or us" (or, WA Minister Troy Buswell's favorite, "This is not a cull"), but with about 100 million sharks killed each year for commercial, recreational, or precautionary purposes, and with over a quarter of all shark species threatened, our favorite marine apex predators are surely getting the short end of the stick.
So perhaps there's no better a time than now for some good cheer. Indeed, a recent study from Brazil suggests promise in a humane, non-lethal, and impressively successful method to keep beaches clean of attacks -- without putting a bullet in anyone's brain.
Recife is a bustling seaside metropolitan center, the fifth largest in Brazil, where skyscrapers are pressed along the coast and small rivers run through the city, lending it the nickname "Brazil's Venice." Although Recife's beaches have been healthily populated with beachgoers since at least the 1950s, there had been no confirmed reports of shark attacks -- that is, until 1992. As if turned on by a switch, shark attacks became alarmingly frequent, shooting to 55 total cases between 1992 and 2011.
Local governments around the world have adopted various ways to "control" sharks, so Recife had a suite of tactics from which to choose. Baited drumlines like the ones used in WA have been deployed to similar ends in the South African province KwaZulu-Natal as well as other Australian states, while many also use nets. While these have more or less secured human safety on beaches, they obviously do kill sharks, and in the case of nets, also do heavy damage to whales, dolphins, and turtles. Most extreme are systematic culls, like the one Hawaii implemented from 1959 to 1976, which slayed over 4,600 sharks but did not reduce shark attacks.
Recife assembled a multidisciplinary team, which included researchers Fábio H. V. Hazin and André S. Afonzo from the Universidade Federal Rural de Pernambuco, to investigate. What they found was that the sharp spike in shark attacks coincided with the construction of a port complex south of Recife. Anthropogenic pressures on the environment were unexpectedly driving a change in sharks' behavior -- once again, we started it.
But instead of shrugging it off with "It's them or us" and reaching for guns, Hazin and Afonzo decided to try something different with the Shark Monitoring Program of Recife (SMPR): instead of capturing and killing, why not capture and relocate?
It turns out that, once a shark is removed from a hazardous area, it won't come back. The tagged tiger sharks they relocated, for example, tended to descend into deeper oceanic waters after their first day of release and continued traveling northwards, away from Recife.
Shark bite incidents plummeted by 97 percent over the course of the four-year study. In fact, during the few intermittent no-fishing periods when the relocation program was temporarily suspended due to insufficient funding, shark attacks actually began to reappear. Among protected species, almost no sharks suffered mortal injury.
SMPR researchers used longlines and drumlines to target a potentially aggressive shark, capture it, tag it, and transport it in a tank with running seawater to another location, taking measures like impact-absorbent material and dark eye covers to reduce damage and stress along the journey. The method was praised by David Shiffman of the Abess Center for Ecosystem Science and Policy at the University of Miami as "brilliant in its simplicity." Shiffman continued, "Huxley once said, 'How extremely stupid not to have thought of that' of Darwin's theory of evolution by natural selection, and many in the shark research world feel similarly of [SMPR]."
Of course, Hazin and Afonzo, as well as other researchers like Jessica J. Meeuwig and Luciana C. Ferreira of the University of Western Australia, caution that capture and relocation is far from a panacea. It proved effective in Recife along a stretch of a few kilometers, whereas WA's ambitious cull covers a much greater expanse. Furthermore, if the "shark-controlled area" lies in special locations like nursing grounds or migration corridors, sharks may be inclined to return, even after relocation.
Meeuwig and Ferreira write, "As we move to an increasingly wired ocean, the next steps are to build on this experience to improve and integrate surveillance and warning systems into mitigation strategies, but for the moment some gains are clear."
Nevertheless, at a time when sharks are routinely picked off for being unfortunately close to beachgoers, any good news is welcome.