Can magnets be used to repel sharks?

Quck answer

Wearing magnets as a shark repellent is a controversial topic. While some studies have shown that magnets may deter sharks from attacking, other studies have found no significant effect. The theory behind using magnets is that sharks have electroreceptors in their snouts that can detect the electrical fields of their prey. Magnets create an opposing electrical field that may confuse or deter sharks. However, the strength and placement of the magnets can greatly affect their effectiveness. It is important to note that wearing magnets should not replace other safety measures, such as avoiding areas known to have high shark populations and following proper diving protocols.

Wild Animals

Shark Magnet Stephen Frink/Oxford Scientific/Getty Images

People have tried various methods to prevent mosquitoes from biting, deer from damaging gardens and bears from destroying campsites. However, there is no guaranteed way to protect against sharks yet. Despite experimenting with specialized sunscreens, chemical sprays, visual tricks and disguises, few have been successful. In 2005, scientists accidentally discovered that sharks swam away from a magnet, leading to further investigation.

During experiments at the Bimini Biological Research Station in the Bahamas, researchers Eric Stroud and Michael Hermann, with the company SharkDefense, found that sharks reacted by darting away from a small magnet dropped in the water. The strength of the repulsion was tested by inducing a temporary paralysis in the sharks and observing their reaction to the magnet. The interaction of salt water and charged metals produces a weak electrical field that seems to disrupt the sharks’ special sixth sense, electroreception. Many shark species have pores on their snouts called ampullae of Lorenzini that detect minute changes of electricity in the seawater, up to one-billionth of a volt. These electrical impulses come from the tiniest muscle contractions of other aquatic life forms and are carried through the ions in the salt water.

However, the magnetic field only deters sharks up to around a foot (0.3 meters) away and multiple magnets would be needed for adequate protection. The distribution and weight of the additional metals could make swimming difficult. Additionally, when sharks are hungry enough, they may continue to pursue something in spite of an uncomfortable electrical field.

Magnetic Response

Hungry sharks may power through an uncomfortable electrical field. See more shark pictures.
Getty Images

Salt water is an ionic solution, meaning it contains particles with unpaired electrons. Because of this quality, salt water can act as an electrical conductor. When a charged magnet comes into contact with salt water, the ions flow through the metal to become stabilized, resulting in the electrical field. The stronger electric fields caused by magnets may overwhelm the sense and send sharks swimming in the opposite direction due to their ability to sense shifts in the surrounding underwater electrical fields through their ampullae of Lorenzini.

Therefore, while magnets may repel sharks to a certain extent, they are not a foolproof method of protection.

The new technology proposed in a patent application by SharkDefense uses electropositive metals to create a magnetic field that repels sharks. This technology could have a greater impact on the commercial fishing industry than on swimmers and surfers, as 20% of sharks are on the brink of extinction due to unintentional capture by commercial fisheries. The National Oceanic and Atmospheric Administration is conducting a detailed study on the potential of this technology, and Ocean Magnetics is exploring the feasibility of magnetic fences to keep sharks away from swimming areas. Shark repellent development began during World War II, and ineffective methods have included a chemical cake called “Shark Chaser” and Protective Oceanic Devices (PODs) that generate a weak electrical field. SharkDefense previously worked on a shark repellent made from chemicals extracted from rotting sharks, but now focuses on using magnets to deter sharks.

Additional Information

Related Articles:

• Surviving a Shark Attack: 15 Tips
• Top 10 Shark Attack Stories
• How Shark Attacks Work
• How Sharks Function
• What is the Typical Diet of Sharks?
• How Bull Sharks Operate
• How Tiger Sharks Function
• How Nurse Sharks Operate
• How Do Sharks Smell, Hear, and See?
• Why Do People Collect Shark Teeth?
• Could Shark Cartilage Be a Cure for Cancer?
• Shark Attack Quiz
• Great White Shark Quiz
• Shark Quiz

Other Useful Links:

• SharkDefense
• Shark Shield
• International Shark Attack File
• MythBusters

Sources:

• Clausen, Lisa. “How to Switch Off Sharks.” Time South Pacific. April 8, 2002.
• Eilperin, Juliet. “Repellent Could Save Humans and Sharks, Too.” The Washington Post. Aug. 8, 2005. (June 9, 2008) http://www.washingtonpost.com/wp-dyn/content/article/2005/08/07 /AR2005080700593.html
• Graber, Cynthia. “Fishing Lines That Repel Sharks.” Scientific American Podcast. May 2, 2008. (June 9, 2008)
• http://www.sciam.com/podcast/episode.cfm?id=A9F7EB36-EF96-74AB-0C6009E5ADE48609
• Katayama, Lisa. “Mixed Signals.” Popular Science. July 2008.
• Moskowitz, Clara. “Electric Signals Could Ward Off Sharks.” LiveScience. May 6, 2008. (June 9, 2008) http://www.livescience.com/animals/080506-shark-repel.html
• Page, Michael Le. “Shark shifter.” New Scientist. Feb. 26, 2005.
• Rajewski, Genevieve. “Geeky Rare-Earth Magnets Repel Sharks.” Wired Magazine. May 15, 2007. (June 9, 2008) http://www.wired.com/gadgets/miscellaneous/news/2007/05/sharkmagnets
• SharkDefense. “Magnetics.” (June 9, 2008) http://www.sharkdefense.com/Magnetics/magnetics.html
• Stroud, Eric. “Elasmobranch-Repelling Electropositive Metals and Methods of Use.” United States 11/800,545. Nov. 8, 2007. (June 9, 2008) http://www.google.com/patents?id=uraiAAAAEBAJ&printsec=abstract&zoom= 4&dq=shark+repellent#PPA1,M1

FAQ

1. Is it true that wearing magnets can repel sharks?

Yes, there are claims that magnets can repel sharks. The idea is that the magnetic field created by the magnets confuses the sharks’ electroreceptors, which they use to locate prey.

2. How do these shark-repelling magnets work?

The magnets are usually attached to a bracelet or anklet, and the magnetic field they create is thought to interfere with the sharks’ ability to detect prey, making the wearer less appealing as a target.

3. Have there been any scientific studies to support the use of magnets to repel sharks?

There have been a few studies on the effectiveness of magnets in repelling sharks. However, the results have been mixed, and more research is needed to confirm their efficacy.

4. Do magnets work on all types of sharks?

It is unclear whether magnets are effective on all species of sharks. Some studies have suggested that they may be more effective on certain species than others.

5. Are there any risks associated with wearing shark-repelling magnets?

There are no known risks associated with wearing shark-repelling magnets. However, it is important to note that they should not be relied upon as a sole means of protection against sharks.

6. Can magnets be used in conjunction with other shark-repelling methods?

Yes, magnets can be used in conjunction with other shark-repelling methods, such as shark repellent sprays or electronic shark deterrent devices.

7. Are there any other benefits to wearing magnets?

Some people believe that wearing magnets can alleviate pain and improve circulation. However, there is no scientific evidence to support these claims.

8. Where can I buy shark-repelling magnets?

Shark-repelling magnets can be purchased online or at certain sporting goods stores. It is important to do your research and buy from a reputable seller.

9. What should I do if I encounter a shark while wearing magnets?

If you encounter a shark while wearing magnets, it is important to remain calm and slowly swim back to shore. It is also important to remember that magnets should not be relied upon as a sole means of protection against sharks.