Swordfish catch decreased when circle hooks were baited with squid but increased when baited with mackerel. Tuna catch increased when circle hooks were baited with squid but decreased when baited with mackerel.
Circle hooks decreased loggerhead and leatherback catch; even more effective for loggerheads when combined with mackerel bait
Effect on target catch:
Circle hooks combined with mackerel bait increased swordfish catch by weight. With squid, decreased swordfish catch, increased bluefin and albacore tuna catch. Mackerel bait decreased bigeye and albacore tuna catch.