Experimental Assessment of Circle Hook Performance and Selectivity in the Northern Gulf of Mexico Recreational Reef Fish Fishery

Circle hooks are required when targeting reef fishes in the U.S. federal waters of the Gulf of Mexico. However, limited data is available to evaluate circle hook performance (e.g., hooking location and catch rate) or selectivity in this fishery. Therefore, a fishing experiment was conducted to test the performance of a range of circle hook sizes (2/ 0 and 4/0 Mustad 39940BLN and 9/0, 12/0, and 15/0 Mustad 39960D) in the recreational reef fish fishery, as well as to estimate hook selectivity directly for Red Snapper Lutjanus campechanus, the most targeted reef fish in the northern Gulf of Mexico. Reef fish communities were surveyed with a micro remotely operated vehicle equipped with a laser scaler and then fished with one of five circle hook sizes. Hooking location typically was in the jaw for all hooks examined, with the mean percentage of jaw hooking being 94.1% for all reef fishes and 92.9% for Red Snapper. Fish size generally increased with hook size but at the cost of a reduced catch rate. The percentage of the catch constituted by Red Snapper decreased from 73% for 2/0 hooks to 60% for 9/0 hooks but then increased to 84% for 15/0 hooks. Dome-shaped (exponential logistic) selectivity functions resulted when fitting candidate models to hook-specific Red Snapper size at catch and remotely operated vehicle laser-scaled size distribution data. While Red Snapper median size at full selectivity increased with circle hook size, the difference in that parameter between the smallest and largest hooks was only 66 mm, or a difference of approximately one age-class. Results of this study suggest that mandating the use of large (e.g., ≥12/0) circle hooks would have relatively little effect on either Red Snapper catch rate or selectivity but would decrease the catch rate for other reef fishes, which would be problematic during closed Red Snapper seasons when fishermen attempt to target other species.