Reducing elasmobranch bycatch: laboratory investigation of rare earth metal and magnetic deterrents with spiny dogfish and Pacific halibut.

Two rare earth metals (neodymium-iron-boride magnets and cerium mischmetal) attached to baited hooks were tested in a laboratory study against inert metal controls to determine the effects of spiny dogfish and Pacific halibut. Spiny dogfish attacked and consumed fewer baits with mischmetal than for the control or magnets. Magnets did not deter dogfish from eating baits, and Pacific halibut showed no reaction to either rare earth metal.
Field Studies:

Location	Fishing gear	Reduction technique	Bycatch species	Effect on bycatch species	Catch	Effect on target catch	Type
Laboratory study	Hooks-and-Lines	Rare earth magnets	Elasmobranchs	Mischmetal reduced the likelihood of an attack or consumption of bait by spiny dogfish.	Pacific halibut	Did not affect halibut	In the wild