North Carolina Sea Grant
Hook, Line & Science

Hook, Line & Science

January 7, 2019 | Dave Shaw

One Hook Clearly Wins in the N.C. Offshore Dead-Bait Troll Fishery 

Almost one-half of North Carolina’s 11 million pounds of marine recreational landings in 2017 came from three species: yellowfin tuna, dolphinfish and wahoo. Clearly, the act of hooking — and then successfully bringing the catch aboard — is important to saltwater anglers! 

Research Need

At the time of this study, fisheries managers were unsure whether to require the use of circle hooks in offshore dead-bait troll fisheries. Some studies had found that circle hooks maintained catch rates but reduced rates of deep hooking for billfishes, compared with J hooks. If circle hooks were required, what impact would it have on catch rates in these troll fisheries? Members of North Carolina’s charter boat industry were eager to find out.

What did they study?

Fisheries scientists partnered with charter and recreational fishermen to compare catch rates for circle hooks and J hooks for three common fish species in the N.C. offshore, dead-bait troll fishery: dolphinfish, yellowfin tuna and wahoo. Prior to testing, scientists and expert fishermen met at a planning workshop to determine the hooks and gears to be tested “side-by-side” on 75 trips. It was important for everyone to come to agree on the parameters, including selecting specific circle hooks that are comparable to the J hooks used in this fishery. The scientists then ran computer models to better understand how such factors as hook type, leader type, species, trip type, and wave height affected catch rates.

What did the results show?

Generally, more fish were caught on J hooks than circle hooks. In fact, computer modelling suggests that fishermen can expect 65 percent greater catches of the three species with J hooks. The results confirm the general observation of the charter boat industry that J hooks perform better than circle hooks in this fishery.

What else did they find?

While king mackerel were not a large proportion of the total catch in this study, the research team found that J hooks also were more effective than circle hooks in catching this species.

Anything else?

As tackle manufacturers continue to introduce new hooks and terminal tackle, will these results hold? They certainly could. The planning workshop for the study generated many novel rigging and fishing techniques with circle hooks, but only the most promising were tested.

Reading

For specific hook descriptions, fishing techniques and more: Rudershausen, Paul J., Jeffrey A. Buckel, Greg E. Bolton, Randy W. Gregory, Tyler W. Averett, and Paul B. Conn. 2012. A comparison between circle hook and J hook performance in the dolphinfish, yellowfin tuna and wahoo troll fishery off North Carolina. Fishery Bulletin 110 (2):156–175.

From Coastwatch: “Hooks in the Gulf Stream: Captains and Scientists Reel in Data”

See also: “Study Finds Circle Hooks Lower Catch Rate For Offshore Anglers”

Summary compiled by Scott Baker
Above photo courtesy of Paul Rudershausen (NCSU)

The text from Hook, Line & Science is available to reprint and republish at no cost with this attribution: Hook, Line & Science, courtesy of Scott Baker and Sara Mirabilio, North Carolina Sea Grant.

 

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