Is Shark Repellent a Actual Factor?

In one of many extra memorable scenes of the 1966 camp masterpiece Batman: the Film, the Caped Crusader ascends a rope ladder to the Batcopter when a big – and really rubbery – shark clamps its jaws round his leg. Unable to dislodge the fiendish fish, Batman calls as much as Robin within the Batcopter and tells him to carry down the Shark Repellent Bat Spray. Losing no time, Boy Marvel nimbly descends the ladder, Batman sprays the shark within the face, and the sinister squalus lets go and falls again into the water – solely to promptly explode. Holy cinema, Batman! However whereas Batman’s spray is clearly meant as a joke, does actual shark repellent really exist – and in that case, does it really work? That is the surprisingly fascinating historical past of shark repellent, which incorporates work executed by famed chef extraordinaire, Julia Baby, amongst numerous others, all to attempt to hold your limbs hooked up whereas foolishly deciding to dip your toes into the massive blue.

The quest to develop the primary shark repellent was launched within the early Nineteen Forties by Henry Subject, anthropologist to U.S. President Franklin D. Roosevelt. Up till this level, the U.S. Navy had seen little use for such a substance, as shark assaults had been exceedingly uncommon and thought of an insignificant risk to naval personnel. In 1941, nevertheless, Subject discovered of an incident through which a navy plane crashed within the Pacific Ocean after working out of gasoline. The pilot swam for hours to achieve the closest land, dragging the physique of his useless copilot behind him. All through the journey, he was adopted by hungry sharks, who slowly tore his comrade’s physique to items. Whereas objectively a freak prevalence, the story nonetheless unfold like wildfire by way of the Navy’s ranks. Fearing a critical drop in morale, Subject urged Roosevelt to approve analysis into shark repellent.

Roosevelt agreed, and in 1942, the duty of growing an efficient shark repellent was given to the newly-formed Workplace of Strategic Providers or OSS – the precursor to the CIA. Preliminary analysis was performed on the Woods Gap Oceanographic Institute in Massachusetts beneath the management of Stewart Springer, an ichthyologist and industrial fisherman and a number one knowledgeable on sharks. As giant, doubtlessly man-eating sharks are slightly tough to work with, Springer performed his experiments on metre-long dogfish sharks. The sharks had been saved in giant tanks and conditioned to eat contemporary bait from small wire cages. By withholding meals for sure intervals of time, Springer was capable of regulate the sharks’ starvation degree and thus gauge the effectiveness of no matter repellent substance was being examined.

Sadly, on the time comparatively little was recognized concerning the physiology and behavior of sharks, leaving Springer with little to go on besides bits of typically doubtful “shark lore” accrued by generations of fishermen. So Springer merely determined to check any substance which may have a repellent impact. He first tried rotenone, a robust toxin recognized to kill fish at low concentrations. Like cyanide, rotenone works by interrupting mobile respiration, stopping fish from absorbing and utilizing oxygen and inflicting them to suffocate. Alas, as Springer shortly found, the concentrations required to kill even small sharks would additionally kill a human. So Springer tried different well-known poisons, akin to sodium cyanide and the sedative quinacrine, however these did little to discourage the sharks; they merely ate the poisoned bait and died later. Dozens of different substances produced equally combined outcomes.

Working out of concepts, Springer turned to some conventional shark lore. Understanding that fishermen alongside the Florida coast hung shark carcasses from their boats to maintain sharks away from their catches, Springer analyzed the fluid extracted from decomposing sharks to be able to pinpoint the lively substances. He found that the 2 most potent compounds had been ammonium acetate and acetic acid – each widespread and cheap chemical compounds. Understanding additionally that copper sulphate was broadly utilized by sailors and fishermen to discourage marine development like barnacles, Springer mixed this with acetic acid to type the compound copper acetate.

Among the many dozens of personnel concerned within the growth of this shark repellent was 30-year-old Julia McWilliams of Pasadena, California. Rejected by each the Military and Navy’s ladies’s divisions on account of her peak – she stood 6’ 2” – McWilliams was readily accepted by the OSS and deployed to Ceylon – right this moment Sri Lanka – after which China. Her first task was typing up hundreds of file playing cards of presidency officers, however she quickly grew bored of this and immediately lobbied OSS founder and director William ‘Wild Invoice” Donovan for tougher work – together with standardizing Springer’s shark repellent formulation. Because it occurred, this could not be her final recipe, for after the warfare she would marry fellow OSS officer Paul Cushing Baby, uncover a love for French cooking, and endlessly change the American culinary and tv panorama because the one and solely Julia Baby.

However whereas copper acetate carried out nicely in laboratory testing, there was no substitute for precise subject trials. So Springer’s group relocated to St. Augustine, Florida, a busy fishing port recognized to be frequented by a number of kinds of sharks. Right here, checks had been performed by hanging two luggage of bait off the strict of a slow-moving boat: one untreated to behave as a management, and the opposite fitted with a slowly-dissolving packet of copper acetate. Preliminary outcomes had been exceptional; whereas 50 sharks of various sorts had been caught on the unprotected bait, the bait protected with copper acetate was solely attacked twice.

However, there was a catch: whereas copper acetate labored nicely in opposition to particular person sharks, it was far much less efficient in opposition to giant teams engaged in a “feeding frenzy.” As most shark assault eventualities had been more likely to contain giant teams of personnel getting into the water without delay, this was one thing of an issue. Serendipitously, nevertheless, round this time Springer’s group was joined by chemists from the Naval Analysis Laboratory, who had been experimenting with soluble fluorescent dye packs to assist rescue plane spot servicemen misplaced at sea. Impressed by this analysis, Springer puzzled whether or not including an opaque dye to the shark repellent would possibly enhance its effectiveness, obscuring the person’s physique just like the ink secreted by octopuses and squid. A suitably dense black dye was quickly discovered within the type of Nigrosine, produced by the Calco Chemical Division of the American Cyanamid Firm. Extremely, in double bait-line testing, this dye proved practically as efficient because the copper acetate – even at night time when the dye was not even seen to sharks. Additional checks performed within the Gulf of Guayaquil in Ecuador and Biloxi, Mississippi in December 1942 produced comparable outcomes; the group lastly had a winner. Springer combined the Nigrosine with the copper acetate, pressed it right into a 3-inch disk-shaped cake, and packed it in a water-resistant pouch that could possibly be hooked up to a sailor or airman’s life preserver. The ensuing repellent was dubbed “Shark Chaser.”

Nonetheless, the Navy remained skeptical, with one lead scientist mentioning in Might 1943 that:

“…none of us anticipated that the chemical would actually perform when the animals had been stirred up in a mob habits sample.”

And whereas Shark Chaser was primarily meant as a morale booster, some anxious that issuing it to servicemen would have the reverse impact, amplifying already overblown fears of man-eating sharks. Ultimately, nevertheless, it was determined that some safety was higher than none, and Shark Chaser was issued to sailors and airmen together with an illustrated pamphlet titled Shark Sense dispelling a few of the extra widespread myths relating to shark assaults.

Distribution of Shark Chaser remained modest till July 30, 1945, when the U.S. Navy suffered the worst shark assault incident in its historical past. On that day, the heavy cruiser U.S.S. Indianapolis, contemporary from delivering components of the Little Boy atomic bomb dropped on Hiroshima to Tinian island, was torpedoed and sunk by the Japanese submarine I-58. Some 900 sailors discovered themselves adrift at sea for 4 days; so secret was the Indianapolis’s mission that her sinking was not instantly reported. Along with dehydration and hypothermia, the survivors had been quickly set upon by dozens of oceanic whitetip and tiger sharks, that are thought to have killed as much as 150 males – and if this sounds unusually acquainted, sure: this is identical catastrophe Robert Shaw’s character Quint recounts within the notorious monologue scene in Jaws.

Within the wake of the Indianapolis catastrophe, the Navy started handing Shark Chaser like sweet. This follow continued for many years, with packets even being issued to the primary Mercury and Gemini astronauts in case they needed to depart their capsules after splashdown. However whereas the Navy claimed that Shark Chaser was 70% efficient, experiments performed by the aptly-named biologist Albert Tester at Enewetak Atoll in 1959 confirmed that many had already suspected for years: Shark Chaser was successfully a placebo with negligible repellent impact. By the Nineteen Seventies, Shark Chaser was not being issued.

At across the similar time as Shark Chaser was being phased out, researchers found that pardaxin, a toxin secreted by a fish known as the Crimson Sea Moses Sole, is very efficient at repelling sharks. Nonetheless, whereas intensive efforts have been made to show pardaxin into an efficient shark repellent, these have confirmed unsuccessful. Not solely is the chemical extremely perishable and tough to retailer, it is just efficient at excessive concentrations, that means it could should be injected immediately right into a shark’s mouth. One other line of analysis has centered on soap-like surfactant compounds like sodium lauryl sulfate, which might repel sharks at concentrations of 100 components per million. Nonetheless, most soluble substances launched into open seawater drop under such concentrations inside minutes, making this yet one more useless finish.

A extra unique method to repelling sharks has been investigated by the U.S. Naval Floor Warfare Middle in Panama Metropolis, Florida. In 2017, researchers on the heart introduced that they’d efficiently created an artificial model of hagfish slime. A primitive, eel-like creature with no scales, bones, or jaws, when attacked, hagfish secrete a particular combination of proteins that, on contact with water, lengthen to over 30 centimeters in size, forming a tricky, viscous gel that may ensnare and suffocate the attacker. To provide the slime in giant portions with out having to reap hagfish, the NSWC genetically modified E.Coli micro organism to fabricate the required proteins – equally to how insulin is produced commercially. Along with repelling sharks, the Navy foresees utilizing the artificial slime for safeguarding ships in opposition to torpedoes, mines, and different explosive weapons.

One other efficient technique of repelling sharks is to make use of electrical energy. Shark’s noses are dotted with lots of of small organs known as Ampulae of Lorenzini, which detect the electrical impulses generated by their prey. Sharks are thus extremely delicate to electromagnetism, and could be deterred by a robust sufficient subject. Certainly, a number of firms together with Sharkbanz and SharkDefense Applied sciences LLC of West Milford, New Jersey, already produce small electromagnetic gadgets that may be strapped to a diver’s wrist or hooked up to their gear to assist chase away sharks. SharkDefense can also be experimenting with using artificial semiochemicals – i.e. shark pheromones – as a possible chemical repellent – a know-how that has proven a lot promise. And in 2014, the KwaZulu-Natal Sharks Board of South Africa introduced that it could be putting in a system of submerged electrified cables beneath fashionable seashores to assist hold sharks at bay.

Curiously, the method that impressed the event of Shark Chaser – mimicking the odour of useless shark – would possibly simply make a comeback. In 2004, researchers Samuel Gruber and Eric Stroud, working on the Shark Lab on the island of Bimini, introduced that they’d developed a extremely efficient repellent known as A2, derived from extracts of decomposing sharks. In contrast to paradaxin, A2 is non-perishable and efficient at very small concentrations, with only some milliliters per minute wanted to repel sharks indefinitely from a bit of submerged bait.

But regardless of these developments, the best protection in opposition to shark assault is sheer likelihood. Yearly there are a mean of 100 shark assaults worldwide, solely round 5 of that are deadly. This offers the typical particular person a lower than 0.00000001% probability of being attacked by a shark – far lower than being struck by lightning or being killed by a falling merchandising machine. Against this, some 50 million sharks are unintentionally caught annually by industrial fishing boats, whereas numerous extra are actively hunted for sport, meals, or to guard these exact same fisheries. Because of this, many more recent shark repellent applied sciences are being developed to not shield individuals from sharks, however the different method round.

Increase for References