There was a total of 69[1] shark attacks worldwide in 2023. Despite having a 1 in 4,332,817 chance of dying, only few are prepared to defend themselves against such an event.[2]
Fortunately, Batman had already used an effective weapon in 1966 when he fought the exploding shark that was sent to kill him. The Penguin managed to get a bomb into the shark and left it near the hologram of Commodore Schmidlapp’s yacht, hoping it would explode when Batman got close to it.[3] Batman attempts to liberate his limb from the jaws of this shark while suspended from a rope ladder on a helicopter over the ocean. Despite repeated assaults, the shark persists in its grip, and it is only after Robin administers the shark-repellent bat spray that Batman is able to escape. The question thus arises what chemical constituents were present in the spray that could have driven away such a persistent shark.
A lot of research has been done on this subject. For example, the Defense Technical Information Center in America has already published a report in 1943 in which they investigated various shark repellents. Copper acetate was found to be the most effective during initial fishing tests where no sharks attacked the copper acetate-protected bait. These tests demonstrated the effectiveness of copper acetate as the nearby unprotected bait caught 26 sharks, indicating that the sharks were actively feeding. However, subsequent tests in conditions where sharks were feeding in packs revealed the limitations of copper acetate. In these scenarios, sharks did not discriminate between treated and untreated bait, reducing the effectiveness of copper acetate to around 50 %. This highlighted the need for an additional repellent to address the ‘mass psychology’ of shark packs. To improve the effectiveness of the repellent, scientists tested black dyes inspired by the defence mechanisms of squid and octopus. The results were promising, as the dye alone significantly reduced shark attacks, even in low visibility conditions. Combining 80 % of the black dye with 20 % copper acetate provided both visual and olfactory deterrence, improving overall effectiveness. However, it should be noted that these tests were only carried out with sharks in the water that didn’t carry a bomb. It is unclear whether these factors could affect a shark’s endurance.[4]
Another approach, which has been suggested by a source whose reliability is open to question, involves combining a proprietary semiochemical compound of Lamniform and Carcarhiniform (75 mL) with dry nitrogen. According to the developers, the “Anti Shark 100” is a mixture of extracts from decaying shark tissue called a “semiochemical” or chemical signal. When released, the cloud of repellent sends a danger signal to any shark in the area, indicating that a predator may be nearby, thus creating a temporary safety zone for the user. However, no data was presented to prove their claim.[5]
In general, a spray should be effective as the gills, eyes and snout are the most sensitive parts of a shark. Applying the spray as shown in the scheme above will therefore be the most efficient. It is worth noting that in the unlikely event of a shark attack, a blow to the shark’s sensitive areas should be sufficient. However, in the Batman shark incident of 1966, the shark contained a bomb. In that case, a shark repellent bat spray is the safer choice, as the bomb is unlikely to be triggered by that action. That would also explain, why Batman was unable to free himself from the grip of the shark as he didn’t utilize his full strength when hitting the animal to not trigger the bomb.[6]
[1] 🙂
[2] Yearly Worldwide Shark Attack Summary. International Shark Attack File. https://www.floridamuseum.ufl.edu/shark-attacks/yearly-worldwide-summary/
[3] Batman
[4] Arlington Hall Station \& Van Deusen, A. H. (1943). A Study of the Use of Chemical Materials as Shark Repellents. https://apps.dtic.mil/sti/tr/pdf/AD0156372.pdf
[5] SharkTec Instant Release Shark Repellent Spray. https://www.adelaidecanoeworks.com.au/safety-rescue/760-sharktec-instant-release-shark-repellent-spray.html
[6] wikiHow. (2015, 29. Juli). Was tun bei einem Haiangriff – wikiHow. https://de.wikihow.com/Was-tun-bei-einem-Haiangriff}
