New research suggests that magnets could effectively deter sharks and rays, reducing the unintentional capture of these animals in baited fish traps and potentially diminishing the need for shark nets to protect swimmers in Australian waters.
Sharks possess sensory pores on the front of their heads that enable them to detect the electrical currents generated by their prey's muscle contractions. This ability allows them to locate their food, even when it's not visible or has a scent.
However, the introduction of strong, unnatural magnetic fields appears to disrupt these sensory capabilities. Raoult likened it to suddenly encountering a strong odour when opening a door, creating an unpleasant experience for the animal.
To test the effectiveness of magnets in deterring sharks from bait traps - large boxes constructed from chicken wire were filled with bait to attract fish along with four three-inch magnetic bars made of ferrite around each funnel. While these magnets may not be much larger than an average fridge magnet, they are thicker and significantly more potent. After meticulously observing approximately 1,100 traps over the course of eight months, the research team discovered that, on average, traps equipped with magnets exhibited a 30 per cent reduction in shark bycatch compared to traps without magnets. With fewer sharks occupying the traps, there was also a remarkable 30 per cent increase in the catch of snapper.
The innovative use of magnets to mitigate shark bycatch in baited fish traps not only promises to safeguard these apex predators but also offers significant benefits to the fishing industry. The findings from this study, where traps with magnets demonstrated a substantial reduction in shark bycatch and a corresponding increase in snapper catch, highlight a promising step toward more sustainable and environmentally friendly fishing practices. With further research and implementation, this approach could potentially reduce the reliance on shark nets to protect swimmers in Australian waters, creating a win-win situation for marine conservation and fisheries.