The Influence of Circle Hooks on the Capture Efficiency and Injury Rate of Walleyes

Abstract

In fisheries managed with conservative regulations, catch-and-release mortality may contribute over one-half of the total fishing mortality. Popular angling literature suggests that circle hooks reduce hooking mortality by reducing the incidence of deep hooking. Anglers fished for walleyes Sander vitreus with circle hooks and octopus hooks (J-hooks) to explore differences in hook efficiency and injury rate. The strike-specific injury rate (SSIR) was defined as the product of four performance ratings: hooking efficiency (H), retention efficiency (R), deep-hooking rate (D), and internal injury rate (I). The H of circle hooks was significantly less than that of octopus hooks. Values of R, D, and I did not differ significantly between circle hooks and octopus hooks, although all three proportions were lower for circle hooks. The circle hook SSIR was 0.12 injuries/strike and was significantly lower than the octopus hook SSIR of 0.27 injuries/strike. Assuming that hooking mortality is proportional to the rate of internal injury of landed fish (D × I), fishing mortality for walleye fisheries could be lowered by the use of circle hooks. Hooking efficiency, which was important in reducing SSIR, is often overlooked in traditional hooking mortality studies that focus on the survival of released fish. Anglers may be unwilling to accept regulations requiring circle hooks if they perceive that the hooks reduce catch rates while not reducing D and I