Shark Attacks and the Surfer’s Dilemma: Cull or Conserve?

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Mick Fanning being attacked by a White shark during the WSL Championship Tour at Jeffrey’s Bay, South Africa, in July 2015.

Sharks are frequently in the headlines these days as a series of attacks across the globe has turned Shark Week into Shark Year. With an unusual number of publicized attacks on the US eastern seaboard, Reunion Island, Australia and in South Africa, hardly a week goes by where the media or local politicians don’t cry out for action to increase the safety of their beaches. Unfortunately surfers are in the cross-hairs on this one with the intense media following the first globally televised attack on Mick Fanning at the J-Bay Open. Recognizing this issue, Surfer magazine had the threat of shark attacks as its cover story this month and surfers are divided on this issue in NSW and Western Australia. So what’s a surfer to do? SRFP-150900-CI1-11005

As a marine biologist I look dimly upon any attempt to “tame” or control our wild ocean. Because sharks are a natural and key component of a healthy ecosystem, I worry about the effects of shark hunts and culls on dwindling shark populations and our oceans, already over-stressed by a wide variety of human impacts. But as a surfer I understand the strong desire to be in the ocean every day, to be able to surf and feel relatively safe while pursuing my lifestyle, one largely free from the worry of being attacked by an aggressive shark. We all care about the ocean but we don’t want to risk our life doing what we love.

This situation sets up a dilemma for surfers, one I discuss here. Can we make the ocean safer for surfers and other beach goers without harmful impacts to the ocean? Are there things we can do to reduce the risk of attacks? After looking at the this issue scientifically my conclusion is maybe. But as is usually the case the devil is in the details. And on this one, perhaps one of the most seminal issues to face surfers beyond climate change, the details are important. However, one fact remains: no matter what we do there is no way to eliminate the threat of shark attacks. It is part of what we do, and like drowning, an inherent risk in the sport.

So here’s a brief review of the current methods used to respond to shark attacks, including hunts, culls, barriers, beach closures, spotters, and research and education. There is quite a bit of scientific literature on the subject, much of it summarized in an excellent paper by Curtis et al. (2012). I’ve also included direct links to many of the regional reports in case you want to dig deeper on your own. Because ultimately I believe it is up to each and every individual surfer to make this decision for themselves.


Shark Hunts

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Results of a shark Hunt in Western Australia. Photo credit: Unknown.

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Newspaper headlines from the 1916 New Jersey Shark Attacks.

One response to an attack is to initiate a public shark hunt in the hopes of capturing the specific shark that caused an attack. The most well know example is the “Twelve Days of Terror” which occurred during a series of five shark attacks in New Jersey in 1916 (Fernicola, 2001) on which the movies Jaws is likely based. Under this scenario the public is recruited to hunt sharks by any means possible as a large uncoordinated, but hopefully successful “hunt” for the responsible shark. Similar hunts have occurred in Australia and South Africa and have been proposed in Hawaii.

Pro: Although it is possible the culprit shark could be caught, this is rarely the case. The hunt may satisfy the political goals of “doing something” in response to a shark attack and help calm the public.

Con: Most of the sharks caught in hunts are not involved in shark attacks and represent immature and/or non-aggressive species. Even if a “man-eating”  shark is captured it is difficult to confirm that it was the actual shark causing the attack. Most of these actions are short-lived and do not have a significant effect on reducing shark populations.

Science: of the three principal species that attack humans, two of them — white and tiger sharks — can migrate up to 30-100 km per day, so it unlikely localized fishing effort would actually eliminate the culprit shark if it was one of these species, although it is possible. However, bull sharks are also known to attack humans and are territorial. Thus, localized efforts would have a higher probability of success for this species. In the New Jersey case hundreds of sharks were killed during “the largest scale animal hunt in history” with funds allocated by the US House of Representatives. A 7.5 ft. juvenile great white was eventually captured not far from the site of the last attacks, and although it is still debated, some scientists believe this was the responsible individual (Fernicola, 2001).


Shark Culls

Zambezi Shark in the nets taken in Durban, Kwa-zulu Natal , South Africa in July 2007

Zambezi (Bull) shark in the nets taken in Durban, Kwa-zulu Natal , South Africa in July 2007. Photo by Fiona Ayerst. From Marine Photo Bank.

“Culls” are government-sponsored shark control programs designed to reduce the abundance of local sharks and (hopefully) the incidence of shark attacks. They may involve contracted fisherman and use baited lines (e.g., drumlines), longlines or nets.  They may be short-term, occurring over 1-2 years, or more long-term. For example, the Shark Meshing (Bather Protection) Program in NSW Australia has been in place since 1937 (Green et al., 2009). Shark culls have occurred in Hawaii, Australia, South Africa and Brazil and have been studied scientifically. However, given the rarity of shark attacks and the nature of studying change in attack rate over time, the conclusions reached by many of these studies should be viewed cautiously.

Pro: Culls reduce the number of sharks in the population and may lower the incidence of shark attacks depending on the location and species involved. In KwaZulu-Natal (KZN) South Africa, for example, incidences involving resident sharks (primarily Bull sharks) declined 90–100% after the use of nets in 1952 but were less efficient for non-resident (transient) sharks, such as great whites or tiger sharks (Curtis et al., 2012). In Queensland, Australia, there has been only a single shark attack since it instituted its net and drumline program in 1962 (Queensland Dept. Fisheries, 2006).  In contrast, a series of short shark control programs implemented in Hawaii from 1959-1976 did not appear to have measurable effects on the rate of attacks (Wetherbee et al., 1994).  Samples derived from culls can provide valuable biological information on the composition of shark species in the area.

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Shark attack rates in Hawaii relative to resident population before, during and after short-term shark control programs from 1959-1976. From Wetherbee et al. (1994)

Con: Culling operations are expensive, can experience significant social and cultural opposition, and can have major impacts on the marine environment. Most of the sharks caught through these operations are immature or unlikely to attack humans. In addition, they may be significant numbers of by-catch (non-targeted) individuals caught, such as dolphins, turtles, whales and seals. By-catch may be very high initially but rates decline over time as the local communities of sharks, dolphins and turtles decline. Some programs, as in Western Australia, may release non-target animals and sharks <3m in length but many die in the nets and on the hook before they can be released. These methods do not eliminate shark attacks completely. In fact, approximately 35-40% of shark entanglements occur on the beach side of the nets in NSW, because sharks are able to swim over and around the nets (Dixon, 2005). Shark culls have been rejected for their high ecological impacts in Western Australia by scientists from Bond University (McPhee, 2012). However, a shark culling program was implemented two years later but stopped in 2014 by objections from WA EPA (The Conversation, 2014).

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Protesters fight shark culls in Western Australia (right). Photo: Brad Hunter / Newspix. Abundance of animals caught in NSW Australia’s net program from 1990-2008 (right). From Guilford, 2015.

Science: Sharks have been a natural predator in marine communities for 100s of million of years and play an essential role in maintaining healthy ecosystems. As the top predators in these systems they limit the abundance of their prey, which in turn has cascading effects in the food chain. By limiting the population of other species sharks increase the species diversity of the ecosystem. As a result, when sharks are removed or reduced in natural ecosystems through human activities, marine communities can change drastically and cause imbalances among species (Myers, 2007). Impacts to non-targeted (by-catch) species can be significant and cause declines in species that are both ecologically important and economically and culturally valuable, such as seals, dolphins, whales and turtles.


Shark Barriers

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A shark prevention net in Hong Kong’s Repulse Bay in 2013. Photo: AFP: Philippe Lopez

Shark fences have been used in various places to physically exclude sharks from bathing areas and are currently used in Queensland, New South Wales, South Australia and Western Australia. These barriers can be small mesh nets, steel bars, wood, concrete or rocks (Curtis et al., 2012).  These barriers are generally limited to small, sheltered areas but are problematic on wave-swept shores due to wave action and erosion.

Pro: When properly maintained barriers can be very effective at eliminated sharks from small areas.

Con: They are very expensive and not effective at most surf locations due to the effects of wave action and can cause beach erosion. When damaged barriers do not provide protection from shark attacks.

Science: These have not been studied to my knowledge. However, it can be surmised that all types of barriers have some small negative effect on the marine environment. Most have no by-catch.


Beach Closures

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Beach closure sign off Vandenberg Air Force Base, California following a shark attack. Photo: Michael Peterson, U.S. Air Force

Closures are an action taken to reduce the risk of a shark attack following a shark sighting, an attack, or other circumstances that may increase the risk of an attack.

Pro: Easy to implement, flexible and low-cost. They may be effective during time periods when high levels of shark prey (e.g., seals) are in the area or when a rogue shark is passing through the area.

Con: They are only a temporary solution and prevent surfers from entering the water. Over time they may reduce beach visitors to the area. Data is required on the type of shark seen in order to make an informed decision.

Science: For transient species, such as great whites, closures may reduce attack risk if the shark is moving through the area. For more locally-attached species, such as bull sharks, or white and tiger sharks attracted to a local resources, closures do little to change the risk of an attack. Without local research on shark composition or movement of tagged sharks, there is usually insufficient information to make this assessment.


Shark Spotters

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Shark Spotter off Cape Town, South Africa. Photos from http://www.wiseoceans.com/seasense/sharks-rays/shark-spotters/

Land-based spotters can help identify developing risks of attack when the area has a high propensity for attacks.  Shark spotters are positioned at strategic points along the coastline with binoculars and in radio contact with another spotter on the beach. If a shark is seen the beach spotter sounds a siren and raises a flag to alert individuals in the water, which are requested to leave the water and return when the appropriate all clear signal is given.

Pro: The Shark Spotters Program in Cape Town, South Africa has proven to be effective warning system and can predict higher risk areas and times and assist in beach closures. The program is relatively low-cost compared to other methods. The program can also assist with swimmers in distress. Since the program began in 2004, they have recorded over 1700 shark sightings (Shark Spotters website) and has collected valuable data on the seasonal occurrence, duration, and distance from shore for each beach (Kock et al., 2012).

Con: Poor water visibility and lack of high ground adjacent to a surf spot limit the effectiveness of the method. The method is not 100% effective and varies based on human experience thus it is important not to create a false sense of security.

Science: Smaller aggressive shark species that do not spent time near the surface, such as bull sharks, are not well identified by this method.


Education and Research

Be Shark Smart

Signage in Cape Town, South Africa to educate beach goers about shark attacks. Source: Fish Hoek Surf Lifesaving Club.

Education can help reduce the risk of attacks by modifying surfer behavior and limit emotional and fearful responses of the public by demonstrating the importance of sharks to healthy marine ecosystems. Common recommendation for minimizing the risk of encounters include:

  • Leaving the water if a shark is sighted;
  • Not surfing alone or far from shore;
  • Not surfing at dawn, dusk or night;
  • Not surfing near seal haul outs or when schools of fish are in the water;
  • Be extra vigilant during certain times of the year when the risk of attack is high (Fall season in California).

Research is key to understanding shark biology, ecology and predicting behavior. Recent advances in electronic tagging and molecular techniques have been important in understanding the migratory patterns of sharks and relationships among global populations. The more we understand about sharks the greater our ability to manage the risk of attack.

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Position of Guadalupe Island female white shark “Gill Rakers” since December, 2012 from electronic tagging information. Since then she has made an amazing trek up along the coast of Oregon, back offshore and then venturing into the Sea of Cortez where it is assumed she went to give birth! – See more at: http://www.marinecsi.org/tagging-updates/#sthash.JxdAW97t.dpuf

Summary

Of all the approaches discussed here our best investment of time and money is education and research, although the shark spotter program has a lot of promise in some areas and use of drones may be another solution. However, despite our best intentions, we do not have control over the ocean, and our feeble attempts to do so are largely a waste of time and resources and can cause significant damage to our marine ecosystems and the animals we care about. The ocean is large, wild and untamed — one of the reasons we are attracted to it in the first place.

Here in Northern California (Humboldt County) the risk of attack is relatively high, with 9 attacks in the last ten years but luckily no fatalities. We don’t want to hear about the low overall risk of attacks because it is very real to everyone in the water. According to local Surfrider coordinator Jennifer Savage, at a recent event there were 5 surfers in the audience that had been attacked. Statistics are not all the comforting.

Ultimately I believe it is up to each and every individual surfer to make a decision on this issue for themselves then advocate for that position at the local level.

  • Is it worth the risk surfing at my local spot?
  • If not, am I willing to cause harm to the ocean to make it safer?

Hopefully this information has been helpful in making a decision which ultimately involves your local community, politicians, and scientists. It is not an easy decision to make.

References:

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