Bulletin of Marine Science
An emerging body of literature has demonstrated the benefits of the use of circle hooks relative to standard J-hooks in commercial and recreational fisheries. In the pelagic longline fishery for tunas (Thunnus spp.) and swordfish (Xiphias gladius Linnaeus, 1758), the use of circle hooks has resulted in greater catch rates of some target species, lower catch rates of some bycatch species, and a higher percentage of many target and bycatch species alive at the time of haulback (gear retrieval). However, a lack of agreement among results of studies conducted in different fisheries and areas, using different baits and rigging techniques, and with different styles and sizes of circle hooks has hindered the adoption of this terminal tackle as a management measure at the international level. Nevertheless, some countries have mandated the use of circle hooks in pelagic longline fisheries to protect bycatch species, and some individual fishers have incorporated circle hooks because they appear to maximize individual profit. In the recreational fishery for billfishes (family Istiophoridae), which is primarily a catch-and-release fishery in the United States, studies have demonstrated that circle hooks result in higher rates of external hooking and post-release survival than standard J-hooks. The use of circle hooks in billfish fisheries has been promoted by the sportfishing industry and is currently required by some nations; however, partnerships promoting active outreach and education with stakeholders in both commercial and recreational fisheries are critical to maximize the use and conservation benefit of this technology.
John E. Graves, Andrij Horodysky, and David W. Kerstetter. 2012. Incorporating Circle Hooks Into Atlantic Pelagic Fisheries: Case Studies from the Commercial Tuna/Swordfish Longline and Recreational Billfish Fisheries .Bulletin of Marine Science , (3) : 411 -422. https://nsuworks.nova.edu/occ_facarticles/497.