MANY rec fishos will be aware of the method of pelagic longlining used by commercial fishers all over the world to target sought after species such as the various tunas. A longline is basically a series of baited hooks all attached to one horizontal main line, that can range from 20 to 40 miles (32 to 64 km) in length. After being left to sit in the water for a period of time, the line is hauled aboard and the catch removed from the hooks. Unfortunately, with this practice many unwanted species fall foul of the longlines including sharks, which are often of protected varieties, or do damage to the lines or bite off hooks.
A new type of fish hook, however, is said to reduce unintended shark catches by up to 94 per cent and may well have applications for rec fishing, especially in shark protection zones which occur in Australia.
The SMART (Selective Magnetic and Repellent-Treated) Hook, created by New Jersey-based Shark Defense, is intended to repel sharks. This is due to the fact that it is magnetic, and coated in a metal that produces an electrical current when placed in seawater. Electromagnetic fields are known to confuse sharks’ sensory systems, and as such the creatures try to steer clear of them when possible. 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.
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.
