Circle hooks

A circular hook design in which the point of the hook is perpendicular to the hook shank. Circle hooks are used widely in many recreational and commercial fisheries and recently have been shown to reduce both the hooking rate and the mortality of turtles that are hooked on pelagic longline gear. As a result of several successful field trials (Bolten and Bjorndal, 2005; Watson et al., 2005), these hooks are becoming increasingly used in longline fisheries.

Challenges of estimating post-release mortality of istiophorid billfishes caught in the recreational fishery: A review

Study Type: 

summary

Effect on bycatch species: 

High speed trolling with J hooks and artificial bait and slow trolling with circle hooks and natural bait resulted in less internal hooking, tissue damage and increase post release survival.

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Hawaii longline tuna fishery temporal trends in standardized catch rates and length distributions and effects on pelagic seamount ecosystems

Study Type: 

wild

Location: 

Pacific

Target catch: 

Tuna

Effect on bycatch species: 

Reduced sea turtle interactions likely due to use of circle and not J hooks

Effect on target catch: 

All tuna species had higher catches rates when wider circle hooks were used. Shortfin spearfish and striped marlin catch rates were lower with circle hooks. No differences in average length between hook types.

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Circle hook effectiveness for the mitigation of sea turtle bycatch and capture of target species in a Brazilian pelagic longline fishery

Study Type: 

wild

Location: 

South-western Atlantic Ocean

Target catch: 

Tuna, blue sharks, swordfish

Effect on bycatch species: 

De-hooking was decreased from 25% to 5.8% in loggerhead sea turtles when circle hooks were used.

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Fishing gear modifications to reduce elasmobranch mortality in pelagic and bottom longline fisheries off Northeast Brazil

Study Type: 

wild

Location: 

Brazil

Target catch: 

Tuna (pelagic) sharks (bottom)

Effect on bycatch species: 

Rates of external hooking were significantly higher with circle hooks

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Fishing gear modifications to reduce elasmobranch mortality in pelagic and bottom longline fisheries off Northeast Brazil

Study Type: 

wild

Location: 

Brazil

Target catch: 

Tuna (pelagic) sharks (bottom)

Effect on bycatch species: 

Mortality at haulback was significantly higher for on J-hooks.

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A comparison of circle hook and J hook performance in a western equatorial Atlantic Ocean pelagic longline fishery

Study Type: 

wild

Location: 

Equatorial Atlantic Ocean

Target catch: 

Tuna

Effect on bycatch species: 

Catch rates were lower for leatherback sea turtles and pelagic stingrays but not sailfish when circle hooks were used

Effect on target catch: 

Bigeye tuna had higher catch rates when circle hooks were used

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A comparison of circle hook and J hook performance in a western equatorial Atlantic Ocean pelagic longline fishery

Study Type: 

wild

Location: 

Equatorial Atlantic Ocean

Target catch: 

Tuna

Effect on target catch: 

Bigeye and yellowfin tuna had higher survival rates when circle hooks were used

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A comparison of circle hook and J hook performance in a western equatorial Atlantic Ocean pelagic longline fishery

Study Type: 

wild

Location: 

Equatorial Atlantic Ocean

Target catch: 

Tuna

Effect on bycatch species: 

Swordfish and sailfish had significantly higher external hookings when circle hooks were used

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Are circle hooks effective in reducing incidental captures of loggerhead sea turtles in a Mediterranean longline fishery?

Study Type: 

wild

Location: 

Strait of Sicily

Target catch: 

Swordfish

Effect on bycatch species: 

J hooks resulted in more hooks being swallowed compared to circle hooks

Effect on target catch: 

None reported

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Experiment to Evaluate Gear Modification on Rates of Sea Turtle Bycatch in the Swordfish Longline Fishery in the Azores Phase 4

Study Type: 

wild

Location: 

Azores

Target catch: 

Swordfish and blue shark

Effect on bycatch species: 

Circle hooks resulted in fewer turtles being caught in the throat

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