Magnetic solution to shark bycatch

We all know that shark populations are declining in many of the world’s oceans. Some of this decline is due to finning, the practice of removing the fins from sharks to supply the shark fin soup market.

But, did you know that often times sharks are caught when trying to fish for something else? This is called bycatch, and countless sharks every year are killed and simply thrown back because they aren’t wanted… To avoid catching these unwanted sharks in the first place, chemist Eric Stroud, working on Bimini Islands in the Bahamas has been developing shark repellent materials. One of these involves producing a magnetic field around fishing hooks that could deter sharks from going after the bait.

These magnets can also be used to keep sharks away from swimming and surfing beaches. Other potential repellents include chemicals, and rare earth metals that seem to be unpleasant to the shark. All of these repellents operate on the principle of producing a negative stimulus if the shark gets too close.

See the full story, as well as a cool video at:

https://www.bbc.co.uk/news/magazine-17792624

3 thoughts on “Magnetic solution to shark bycatch”

  1. Do you know if the magnets cause any harm to the shark’s ampullae of Lorenzini? Like of it would throw off thier ability to locate food and navigate if they were exposed to the magnets to much? I think it would be a great solution to develop to decrease sharks and bycatch but only if it was proven not to harm the sharks at all.

    1. Good question, as far as I know, there have been no studies testing whether creating strong electro-magnetic fields causes damage to the electro-sensory organs of sharks. It’s a very important question to answer before this gets used extensively. But there are a few things to keep in mind. To examine the effects of magnets on sharks, we have to subject them to the effects of the magnet, but in reality, we are hoping that these magnets will keep them away from the hooks at all, so the shark would turn away from the magnetic field presumably before the magnet caused any damage to the shark.

      A good analogy for us would be a constant very loud noise. If we are sitting in quiet room and all of sudden there is a huge explosion, it would damage our hearing, perhaps permanently. But if there was a source of constant, very loud noise out there somewhere, most people would just stay away from it and not get close enough to cause damage to their hearing.

      But can anybody think of one way that this strategy to keep sharks away form hooks could fail in the long term?

      If you are interested in learning more about this subject, there is a short paper that explains it pretty well: O’Connell, Abel, Rice, Stroud, Simuro. 2010. Responses of the southern stingray (Dasyatis americana) and the nurse shark (Ginglymostoma cirratum) to permanent magnets. Marine and Freshwater Behaviour and Physiology 43:63-73.

      Let me know if you have any trouble finding it.

  2. I have watched a few documenteries on this subject and have no reasion to belive that it cause perminent damage. in contained studies sharks that where subjected to the magnetic fields showed no residual effects immediately afterwards. I cant say that it wouldnt come back to harm them later in their life span though.

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