Summary
Rare earth metals (made of cerium mischmetal) were compared with control treatments of standard circle hooks and inert steel above circle hooks on longline fishing gear to determine if bycatch reduction of spiny dogfish (Squalus acanthias) could be achieved. Results indicated a slight reduction in dogfish bycatch and a greater reduction in catch of longnose skate (Caliraja rhina) on hooks with mischmetal. Problems for using mischmetal commercially include its expense, hazardous nature, and rapid hydrolysis in seawater.