I’m a shark biologist and I also love to surf. One of my favourite surfing memories isn’t one of my rides, however, but of being a spectator. I remember standing on the Waimea shoreline in 2009, feeling the beach shake as enormous waves thundered to a close. Moments before, my favourite surfer had just scored a 98 point ride in the prestigious “Eddie” competition, named in honour of Hawaiian surfing legend Eddie Aikau. That surfer was Kelly Slater.



Slater’s name is currently synonymous with sharks because of comments he made following the tragic death of body boarder Alexandre Naussac on 21 February 2017 in the waters of Reunion Island. Naussac was killed by a bite by a bull shark, and in the shock that followed, Slater spoke out, backing the long-held views of Reunion Island local and pro surfer Jeremy Flores, and called for a cull on the sharks around Reunion. This quickly led to a barrage of online attacks and misinformation from people on both sides of the argument.

Upon seeing Slater’s initial response I was disappointed but not surprised. Considering his usual pro-environmental views I was hoping that his response was an understandably emotional reaction to the death of a member of the surfing community, as opposed to a fundamental change in his stance on shark conservation. After all, he had previously condemned shark culls in Western Australia in 2014.

Indeed, a few days after his calls for a cull, Slater addressed the comments in a conversation with Paul Watson of Sea Shepherd: “I did not think my words through. It is easy to get emotional given the recent history with sharks that the local community has suffered, especially when young lives are lost. However, killing anything in hopes of a solution is not in line with my philosophies about life and I don’t believe are a long term fix to an ongoing problem. This is a good time to put energy and intelligence into finding a solution that works for everyone … utilising technology, science and human emotion. I know a solution can be found that works for all parties. I’ll continue to learn about and put energy towards efforts to defend and protect our oceans.”

I would argue that Slater has ultimately done everyone – sharks included – a favour. He has thrust the issue into the media spotlight, and in doing so has revealed just how fractured the relationship and understanding is between scientists, surfers, politicians, conservationists, media and the public.

Facebook Twitter Pinterest Kelly Slater surfing at Waimea. Photograph: Lauren Smith

Aquatic sports are increasing in popularity. This, along with the increased accessibility of remote locations and technological advances – such as better wetsuit design – which allow people to stay in the water for longer combine to increase the potential for more human-shark interactions.

So, what strategies are most effective at ensuring the safety of ocean users? Currently, several methods are in use:

Aerial patrols use helicopters or small planes to spot the presence of any large sharks. This is costly and weather dependent, although the cost, at least, may fall if drone technology is used.

Shark spotters based on land are trained to identify sharks in specific areas and to alert those in the water. This is limited by visibility, accessibility and availability of staff, who are usually volunteers.

Beach closures sometimes put in place following sightings of large sharks. However, this assumes people will take heed and stay out of the water.

Shark-free enclosures are sometimes created in very small areas to provide a designated swimming space, although this is not applicable for surf spots.

Shark nets are placed across large areas, usually at the openings of bay areas. However, these result in entrapments and death of many animals including turtles, fish, dolphins, birds etc as well as sharks.

Drum lines use baited hooks, and sharks are caught and shot. This is the method most often associated with a cull.

Non-lethal capture is used in Recife, Brazil, whereby sharks are caught and then towed out to sea and released. This has proven an effective strategy, reducing shark bites incidents by 97% without killing threatened species of sharks.



Repellent research. Recent scientific investigations have focused on the approaches including chemical, acoustic, visual and electro-magnetic repellents. The latter is an area that I have worked on, and essentially looks for a way to overstimulate the sharks’ electrosensory system enough to produce a repellent response.

But what about Reunion Island itself? It is true that when you consider the length of the coastline (207km) alongside the number of shark bites (21 since 2007), in comparison to other locations around the world, the rate is high. So why is this?

Many possibilities have been suggested as potential causes: overfishing of reef fish and reef sharks, thus reducing natural sources of prey for bull sharks; pollution and upriver developments resulting in poor underwater visibility, which potentially makes exploratory bites more likely; the prevalence of fish farms, as well as the reported dumping of sewage, fish waste and animal offal.

Facebook Twitter Pinterest Bull shark and bait in non-lethal capture. Photograph: Lauren Smith

Of these suggestions I can find only one published scientific study that has investigated claims to see if they can be substantiated. In fact, few studies have concentrated on the sharks around Reunion Island, so relatively little is known about the ecology of these sharks.

Loiseau et al. used an unbaited stationary video camera to investigate the behaviour and interactions of bull sharks under an aquaculture farm. This is something that has been documented in other shark species around the Canary Islands and in Hawaii. Blaison et al. revealed that juvenile, sub-adult and young tiger sharks were found year round at Reunion, with tagged animals showing seasonal variation between sexes. Mature tagged bull sharks of both sexes were more abundant in winter than in summer, with only females present year round.

What these studies highlight is how little we know about these sharks, their movements and their habitat usage. This is evidence enough that a cull won’t work. Even if we ignore for a moment the ethical and ecosystem reasons for retaining the bull and tiger sharks in the waters around the island, culling would only be effective if you could draw a line showing that all of these sharks were resident 100% of the time and there was zero migration of these sharks or any others in the surrounding vicinity.

Aside from the obvious requirement for research to be undertaken on these sharks, there is an urgent need for education, because with all the research and technology in the world, human-shark interactions will never be completely eliminated. As such, education campaigns will promote safer behaviours in water users. These include things such as avoiding being in the water at dawn and dusk, avoiding areas where fishing is occurring, avoiding murky estuarine environments to name but a few strategies.

This information, alongside the need for scientific research, is what the recently founded Surfers4sharks campaign is eager to disseminate among the surfing community. Given the recent online rhetoric this may not prove a simple task, and yet it is one for which there is an urgent need. We must replace fear and hate with knowledge and compassion. Only then can we move forward and reduce negative interactions between humans and sharks in the waters around Reunion Island and elsewhere.

References



Loiseau, N., et al. “Using an unbaited stationary video system to investigate the behaviour and interactions of bull sharks Carcharhinus leucas under an aquaculture farm.” African Journal of Marine Science 38.1 (2016): 73-79.

Boyra, Arturo, et al. “Attraction of wild coastal fishes to an Atlantic subtropical cage fish farms, Gran Canaria, Canary Islands.” Environmental Biology of Fishes 70.4 (2004): 393-401.

Papastamatiou, Yannis P., et al. “Site fidelity and movements of sharks associated with ocean-farming cages in Hawaii.” Marine and Freshwater Research 61.12 (2011): 1366-1375.

Blaison, A., et al. “Seasonal variability of bull and tiger shark presence on the west coast of Reunion Island, western Indian Ocean.” African Journal of Marine Science 37.2 (2015): 199-208.