Largemouth bass catch rates and injury associated with non-offset and offset circle hook configurations

Although circle hooks are being viewed as a means to reduce injury and mortality of recreationally caught-and-released fish, subtle differences in hook configuration (such as the degree that the hook point is offset from the shank) could affect performance. We compared hooking and landing efficiency, anatomical hooking depth and location, ease of hook removal, and amount of bleeding between largemouth bass angled on either non-offset (0°) or slightly offset (2°) circle hooks. Non-offset circle hooks were more efficient at hooking and landing largemouth bass than the offset design. Fish were hooked more deeply with non-offset hooks; non-offset hooks penetrated the corner of the mouth whereas the offset hooks penetrated the terminal upper and lower lip. Overall, there were no differences in the frequency that fish were hooked in potentially lethal locations (e.g. gullet, eye). The design and hooking location of non-offset hooks led to greater difficulty in hook removal and slightly higher rates of bleeding. Offset circle hooks have been identified as more injurious in previous studies but we found little difference in injury that may lead to serious infection or mortality between hook types. Given that non-offset circle hooks have a higher capture efficiency for largemouth bass, anglers will likely adopt their use.