George Burgess, director of the Florida Program for Shark Research and coordinator of museum operations at the Florida Museum of Natural History, explains why culling sharks to reduce the risk of attacks will not work, despite the call from professional surfers to do so.
The warm and productive waters of La Réunion, an island east of Madagascar in the Indian Ocean, are home to many types of tropical sea life, including apex predators such as sharks. Eight fatal shark attacks on humans have occurred there since 2011. After a body boarder was killed by a shark on Feb. 21, professional surfers Kelly Slater and Jeremy Flores called for aggressive shark culling around the island.
Calls for sanctioned killing of sharks usually are the initial gut reaction from a community experiencing its first “Jaws” scare. Such sacrificial kills appear motivated in equal parts by a desire for revenge and the thought that killing sharks will ensure personal safety.
But shark scientists like me agree that there is virtually no chance to catch the highly mobile offending individual, and that there have been precious few documented cases of repeat offenders, or “rogue sharks.”
I study these attacks as curator of the International Shark Attack File (ISAF). Proposals for culling sharks reflect the anthropocentric notion that the sea belongs to humans, and we are owed complete safety when immersed. In fact, however, human actions have contributed to the shark-human dynamic around La Réunion, and culling will not substantially reduce the risk there.
Sharks are low-density, highly migratory animals that readily recolonize areas denuded of their kind, rendering any attempt to cull an ineffective strategy. And while Slater suggested that culling bull sharks around La Réunion might benefit other species, it is impossible in practice to limit shark hunts to target species. As a result, many nondangerous sharks are killed in an attempt to catch the few dangerous species.
Why are there so many attacks at La Réunion?
Periodically, a higher-than-normal number of encounters between sharks and humans occur in a discrete geographic area. In some cases those encounters result in bona fide attacks that cause major injuries or deaths. At ISAF, we have consulted with numerous state governments and local authorities over the past 30 years when these spikes occur. In every case we have identified specific natural or human-induced environmental disruptions or changes in patterns of human activities around water as likely contributors.
La Réunion has been on ISAF’s radar for five decades as an area with higher-than-usual per capita traumatic shark-human encounters. Over this time period the island population has doubled. There also have been noticeable habitat modifications – notably, degradation of nearshore coral reefs – which have reduced the abundance and diversity of the island’s fish communities. Since all parts of an ecosystem are inexorably linked, apex and near-apex predators are intimately affected.
Island residents are well aware that bull and tiger sharks are present and white sharks appear occasionally in La Réunion’s waters. These are the three shark species most often documented in serious shark attacks, and islanders know that the likelihood of encounters is higher in certain areas. The government banned swimming and surfing around much of the island in 2013, but surfing competitions resumed in 2015 at two beaches protected by safety nets and lookouts.
Tourism has increased in the region, and the number of surfers has risen over the past 30 years. As often is the case in emerging tropical tourist destinations, some visitors do not seek local information about safety conditions before entering the water, and suffer the consequences of wandering into a danger zone. Last week’s death reportedly occurred at an area that was officially closed to swimmers, but warning signs at the beach had been vandalized.
Growing interest in surfing among both La Réunion residents and visitors is especially significant because surfers are the single most shark-affected group among aquatic recreationists. Increased shark attacks since the 1950s in many areas of the world, including Florida, Hawaii, California, Australia and Brazil, are directly linked to increased hours spent surfing in the ocean.
Surfers and local governments can take steps to reduce risks, such as avoiding high shark-contact surfing locations, choosing appropriate times of day to surf, hiring shark spotters, improving rescue and medical capabilities, and educating the public about sharks. But surfers, who are among the most enthusiastic supporters of shark conservation, know that surfing is an activity that comes with inherent risk. Ultimately each surfer must make wise judgments about where and when to engage in his or her chosen passion.
The ocean as wilderness
The reality is that humans are visiting an alien environment when we enter the sea, and are engaging in a wilderness experience for which we often are poorly prepared. We all know we might drown, and we may suffer spinal injury, lacerations or scrapes if the surf tumbles us onto hard-packed sand or reef. Or we could be stung by jellyfish or sea lice, step on a stingray or be bitten by a shark.
The risk of being killed by a shark is extremely low. In 2016 only four people died worldwide as the result of shark attacks while engaged in all types of aquatic activities. Meanwhile, because of overfishing, shark populations have plummeted around the globe. Even great white sharks, the top dogs of the ocean, are legally listed as threatened or endangered in many areas of the world.
Authorities in La Réunion have determined that certain beaches present a higher shark risk to swimmers and surfers than other areas. Those beaches are closed to aquatic recreation, and people can learn about the risks from signs and word of mouth. Those who choose to ignore such warnings must accept the risk, just as surfers accept the degree of difficulty associated with surfing high-risk breaks.
And if a serious attack or a drowning occurs, no one should blame the sea or its denizens for our risky behavior. The sad truth is that thousands of drowned surfers are memorialized for dying while doing what they enjoyed, while it’s always the shark’s fault after the rare fatal attack.