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This news is a couple of months old but I found it interesting and just now stumbled upon it. A New Jersey-based Shark Defense company developed the SMART (Selective Magnetic and Repellent-Treated) Hook that is intended to repel sharks but does not affect other types of fish. It is magnetic and coated with a metal that produces an electrical current when placed in seawater. Electromagnetic fields are known to affect sharks' sensory systems they try to steer clear of them when possible. Market-valuable fish, such as tuna, do not have this electrical sense and are not repelled by the hook. It requires no power source, and reportedly only costs slightly more than a traditional hook (an amount that should be made back through reductions in damaged equipment, wasted time, and unmarketable catches).
In a set of 50 tests using two different groups of sharks, it was found that smaller, recreational-sized SMART hooks with bait received 66 percent less shark strikes than their conventional counterparts. Larger, commercial-sized SMART hooks received 94 percent less, due to the fact that more of the shark-repellent metal was present.
As reported by Live Science, the original work was sponsored by NSF SBIR grant. "Combining a magnetic repellent with a galvanic repellent is very important, because many studies have shown that sharks behave differently to magnets or metals alone," said Craig O'Connell, who researches the effects of magnetism in sharks with Shark Defense and publishes on the subject. "There are many species of shark, and they seek out their prey differently. Having two repellents available increases the chances that the sharks will be deterred."Magnetic and voltage-creating metals have separately been shown to reduce shark catches by 18 to 68 percent in past studies, although the Shark Defense researchers state that combining the two properties boosts the SMART hook's repellent properties.
EM waves have many uses!