Field study in the wild
Effect on target catch:
Albacore catches increased with circle hooks on both types of longline. Shortfin mako shark catch rates increased with circle hooks on the American style longlines.
Effect on bycatch species:
American style longlines - no significant difference in catch rates for blue or porbeagle sharks, seabirds or sea turtles. Spanish style longline - significant decrease in pelagic stingray catch rates on circle hooks, no significant differences in catch