Shark Deterrent Technology | What Actually Works
On December 13, 1958, fifteen-year-old Billy Weaver was surfing with five friends off Lanikai Beach, east of Honolulu. The water was warm – it was Christmas time in Hawaii, and the temperature hovered around 80 degrees. What started as a typical day in paradise turned tragic when Billy slid off his air mat about 50 yards from his friends.
“We were about 50 yards from Billy when we saw him slide off his mat into the water,” his friend Terry Oakland, 14, would later recall. When Terry reached his friend, he heard Billy scream “Help!” before being pulled under by a shark nearly 20 feet long. Despite his friends’ desperate attempts to save him, Billy was lost to the attack, his body later found wedged in a reef with devastating injuries.
Billy’s death sparked immediate action. Within days, community leaders and government officials launched the Billy Weaver Shark Control Fund, raising over $27,000 for shark control measures. The tragedy catalyzed Hawaii’s first organized attempt at shark deterrent development – and in many ways, launched the modern era of shark defence technology.
Today, as surfers browse through a growing market of shark deterrent products – from $175 Sharkbanz magnetic wristbands to $30 “Shark Eyes” stickers – many ask the same question that haunted Billy’s friends: how can we effectively protect ourselves from sharks?
The answer isn’t simple.
While some modern shark deterrents have shown promising results in scientific testing, others rely more on marketing than evidence. Shark deterrents are currently the only safety devices in Australia that don’t have to meet our national standards – meaning anyone can market a product and make claims about its effectiveness.
In the history of human-shark encounters, few quests have inspired more ingenuity – or more misguided solutions – than the search for effective shark deterrents. From military-grade explosives to chemical warfare, the 20th century witnessed an extraordinary parade of attempted shark defence methods, each telling its own story about our evolving understanding of these apex predators.
The War Years ‘Operation Shark Repellent’
In 1942, fear of sharks had become more than just a water safety issue – it was affecting military morale. Anxious mothers wrote to their congressmen and even to President Roosevelt himself, worried about their sons facing sharks in distant waters. The psychological impact was so significant that Roosevelt personally ordered the creation of a shark repellent programme, launching one of the most unusual military research projects of World War II.
The search for a shark repellent led scientists on an international chase that reached the highest diplomatic channels. In December 1942, Secretary of State Cordell Hull himself had to cable the American Embassy in Ecuador, requesting permission for shark researchers to access their waters. Ironically, when the researchers arrived, they faced an unexpected problem: they couldn’t find enough sharks to test their repellents on.
The Birth of “Shark Chaser”
After testing 78 different substances – including various poison gases – researchers discovered that decomposing shark meat seemed to repel live sharks. This led to the development of “Shark Chaser,” a mixture of copper acetate and nigrosine dye. The Borden Company’s Shark Industries Division in Salerno, Florida, began producing it, filling the air with such a terrible smell that locals wondered what classified military project was underway.
Yet real-world tests would later reveal its limitations. In one dramatic instance, Australian shark hunter Bob Dyer tested it on shark packs feeding near whale carcasses. Some sharks were repelled, but others were so frenzied they actually ate the repellent packets themselves.
The Bubble Barrier Fiasco
The 1960s saw perhaps the most creative – and ultimately futile – attempt at shark defence: the bubble fence.
Following John Brodeur’s horrific shark attack in waist-deep water off Sea Girt, New Jersey, in 1960, resort owners desperately sought solutions to protect their beaches and their businesses.
The bubble fence seemed like an elegant answer: a perforated pipe on the ocean floor releasing a curtain of bubbles that would supposedly terrify sharks. Its inventor claimed sharks wouldn’t cross it “even for a juicy steak.” Resort owners saw it as their salvation, but Dr Perry Gilbert’s subsequent testing would expose a different reality.
At the Lerner Marine Laboratory in Bimini, Gilbert conducted rigorous tests using Tiger sharks ranging from 5½ to 13 feet long. The results were unequivocal: sharks swam through the bubble curtain as casually as walking through a door. In one 10-minute period, sharks crossed the barrier 77 times.
One particularly determined 900-pound Tiger shark seemed to treat the bubbles as more of an amusing distraction than a deterrent.
The Navys Solution: ‘Operation Depth Charge’
In 1958, the South African Navy frigate Vrystaat provided perhaps the most spectacular failed attempt at shark control.
Picture the scene: a large warship deploying military-grade explosives against… fish. Each depth charge sending great geysers of water high into the sky on detonation. While they killed ahem… seven sharks, they created an even bigger problem.
Commander James Starkey, who witnessed similar attempts during WWII, reported a chilling effect: “Within 20 seconds of an underwater explosion, the area would be swarming with sharks feeding on stunned fish. What started as an attempt to protect swimmers often turned into an inadvertent shark feeding frenzy.”
The Mesh Net Revolution
Among all these dramatic failures, one method emerged with a measure of success: mesh nets. The story begins in Sydney, Australia, in 1934, when a series of fatal attacks led to the formation of the Shark Menace Committee. Their solution – nightly deployment of mesh nets – was initially dismissed as “a stupid, futile waste of money.”
Despite the criticism, Sydney implemented its meshing programme in 1937. The results were striking: in the first year alone, 751 sharks were caught. By 1948, that number had dropped to 260, suggesting a significant reduction in the local shark population.
Most importantly, since the programme’s implementation, there hasn’t been a single recorded shark attack at a meshed Sydney beach.
This success story comes with caveats. The shark nets were meant to work like a protective barrier, catching sharks before they could reach swimming areas. But in 1964, divers checking the nets made a disturbing discovery that changed how we understood their effectiveness.
Imagine the nets like a line in the water between the open ocean and the beach. When divers examined caught sharks, they expected to find all the sharks caught while swimming toward the beach (from ocean to shore). Instead, they found some sharks were caught while swimming in the opposite direction (from shore to ocean).
This meant two important things:
- These sharks had already gotten past the nets and into the swimming area
- They were only caught when trying to swim back out to sea
So rather than acting as a protective wall keeping sharks out, the nets were just catching sharks going both ways – sometimes only after they’d already been in the swimming area. While the nets did reduce shark numbers overall, they weren’t providing the complete barrier protection many people assumed they were.
Dangerous Myths – The Wild West of Shark Advice
The 1950s and ’60s saw an explosion of dubious shark defence advice that makes modern marine biologists cringe. One skin-diving magazine infamously suggested: “You can actually swim up to a Nurse shark and kick it without eliciting harm to your person. Try it some time.” Another advised readers to engage in “hand-to-shark combat” by jamming their fingers into the shark’s gill slits.
The Cousteau Encounter
Famous oceanographer Jacques Cousteau’s experience provides a sobering counterpoint to such advice. While diving off the Cape Verde Islands with Frederick Dumas, they encountered three aggressive sharks. They tried everything the manuals suggested: flailing their arms, releasing bubbles, yelling underwater, and using shark repellent. Nothing worked. Even hitting one shark on the snout with a camera only temporarily deterred it.
This encounter led Cousteau to develop “shark billies” – 4-foot clubs studded with nails – after observing sharks swimming “unshaken with harpoons through their heads, deep spear gashes on their bodies, and even after sharp explosions near their brains.”
Real Survival Stories
Sometimes, desperate circumstances required desperate measures. Captain Jonathan Brown’s 1958 survival story in the Pacific illustrates when aggressive defence becomes necessary. After his C-124 Globemaster crashed, Brown and two crew members spent 12 hours in shark-infested waters. When a shark grabbed his shoulder, Brown’s only option was to fight back.
“The shark had me by the shoulder and was shaking me,” Brown recalled. “We yelled, thrashed and kicked about in the water trying to get rid of it. Finally, I beat on its head with my fist and it let go.” While Brown survived, his experience underscores that such defensive measures should only be last resorts.
Modern vs Historical Assumptions
Our understanding of shark behaviour has evolved dramatically since these early attempts at shark defence. There are sharks and sharks. One repellent may work with the Tiger shark, but not with the Grey sharks. Another may work with the Grey and not on the Tiger.
Modern research has revealed that:
- Shark species exhibit distinct behavioural patterns
- Individual sharks within the same species can show different personalities
- Environmental factors significantly influence shark behaviour
- Feeding patterns can range from cautious investigation to aggressive rushing
- No single deterrent works consistently across all situations
Modern Shark Deterrents
The market for shark deterrents has exploded in recent years, offering everything from electric fields to magnets, visual deterrents to olfactory repellents. These safety devices are unique in Australia for their lack of national standards, there’s no guarantee or very little evidence to suggest the products deliver on their marketing claims.
Electric Field Technology – The Leading Edge
Recent research by Professor Charlie Huveneers at Flinders University has provided compelling evidence for the effectiveness of electric field deterrents. In controlled trials with great white sharks off South Australia’s coast, these devices reduced shark attacks on baited surfboards by more than half – from 96% to 40%. Similar studies with bull sharks showed a 40% reduction in bait taking.
The technology works by overwhelming the sharks’ electroreceptors – known as ampullae of Lorenzini – which they use to detect tiny electrical fields. However, these devices have limitations: their effective range is typically just over a metre, as electricity dissipates exponentially in seawater.
Visual Deterrents – Big Question Mark
Throughout the natural world, animals use eye patterns in two distinctly different ways, and this creates a fundamental problem for visual shark deterrents.
Some creatures, like butterflies, use eye patterns to ward off predators by making them feel watched, many fish species use false eye spots to deliberately draw predator attacks to less vulnerable parts of their body.
When manufacturers add large eye patterns to surfboards, they’re assuming sharks will be deterred like the butterfly’s predators – but they might instead be creating a target like the fish’s false eyes. Sharks need to orient themselves to their prey, identifying which end is which for an effective attack. By adding eye patterns to surfboards, we might inadvertently be giving sharks a clear targeting system.
This is particularly concerning because, unlike fish who place their false eyes away from vital areas, surfboard eyes are typically near the surfer’s actual body.
There’s currently no solid scientific evidence supporting these visual deterrents’ effectiveness, and they could potentially be making surfers more vulnerable rather than safer.
The Return of Olfactory Repellents
While the World War II-era “Shark Chaser” proved ineffective, modern research into necromones – chemicals from decomposing shark tissue – has shown promise with certain species. Caribbean reef sharks and blacknose sharks have demonstrated aversion to these compounds. This approach isn’t universal: tiger sharks and white sharks eat other sharks!
Magnetic Approaches and Sound
Permanent magnets have shown some effectiveness, particularly in fishing applications where they reduced unwanted shark catches by a third. Their effective range is limited to centimetres rather than metres. More promising are electromagnetic devices, which use power to amplify the magnetic field.
A novel approach being tested uses acoustic deterrents – specifically, recordings of orca calls. While early trials show promise, this could raise a whole other set of environmental issues.
Commercial Fishing Applications
The fishing industry has become a major testing ground for shark deterrent technology. Recent studies combining electric, magnetic, and acoustic approaches showed promising results, with fishers retaining 60% more of their catch when using deterrent devices.
Lessons of History
The most valuable lesson from this history of shark defence might be humility. It must be remembered above all that sharks are unpredictable. Each failed solution has taught us something about shark behaviour, leading to more nuanced and effective approaches to beach safety.
The future likely lies not in finding a perfect deterrent, but in developing multiple, complementary approaches based on better understanding of shark behaviour. While we continue to search for better ways to coexist with sharks, the history of shark defence reminds us that respect and caution remain our most reliable protections.
For as Jacques Cousteau wisely observed after his close encounter, any shark defence may prove to be “merely another theoretical defence against the creature which has eluded man’s understanding.” Yet each generation’s attempts, even the failed ones, bring us closer to that understanding.
Explore More
- Sharks of Australia | Fascinating Facts and Species Guide Dive into the diverse world of Australian sharks, from their unique adaptations to their critical ecological roles.
- Wildlife-Safe Netting | Protecting Marine Life Discover how wildlife-safe netting helps protect Australia’s marine creatures while ensuring fishing sustainability.
- Shark Attacks in Australia | Myths vs Reality Separate fact from fiction as you explore the realities of shark attacks in Australian waters.
- Megalodon | The Largest Shark That Ever Lived Learn about the legendary Megalodon and what its existence reveals about prehistoric oceans.
- Rare and Real Dangers | Comprehensive Shark Attack Guide Understand the science and statistics behind shark attacks and how to stay safe in the water.
