The SMART Hook (Selective Magnetic and Repellent-Treated Hook) is a fishing hook incorporated with both electropositive metals and magnets, designed to deter elasmobranchs (sharks, skates and rays) from fishing gear. Elasmobranchs are sensitive to both electropositive metals and magnets, due to the electroreceptors in their noses.
The combination of both electropositive metal and magnetic deterrents is deemed important, as studies have shown variations in elasmobranchs’ response to metals or magnets alone – the use of both could reduce elasmobranch bycatch on SMART hooks.
In 2010, Shark Defense conducted feeding trials with bonnethead sharks in tanks, using first regular hooks and then SMART Hooks. Following 50 tests, researchers found a 94% reduction in baits eaten when using SMART Hooks.
The SMART Hook has also been studied in a longline fishery in the Gulf of Maine with various elasmobranch bycatch species. Following 26 days of deploying the device on longline gear, a 28.2% reduction in spiny dogfish capture was demonstrated. However, the study observed no reduction in thorny skate or barndoor skate capture. Laboratory analyses suggested that SMART Hooks produce a mean voltage of 1.05 eV for 5 days, after which time the metal rapidly dissolved and the voltage dissipated, thus their long-term effectiveness requires further study.
This page was last updated on 12.02.21.
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