Electromagnetic deterrents

Electromagnetic fields created in the vicinity of a fishing activity to deter interaction of non-target species with fishing gear, bait, or target species. For example, rare earth metals, such as cerium or lanthanide, are attached or imbedded into hooks (longline, hook and line etc.) in an effort to deter the incidental bycatch of sharks and rays (Tallack et al. 2009). The main prize of the 2006 Smart Gear competition run by the World Wildlife Fund was for a magnetic shark deterrent to be tested on pelagic longlines. Polet et al (2005) describe evaluations of an "electro-trawl" in which electric charges stimulated shrimp into moving upward from the sea floor into the path of the trawl mouth. In this approach, the space between the groundrope and the benthos might be increased without reducing target catch levels but decreasing the contact the trawl might have with some non-target benthic invertebrates and groundfish.