Injury rates, hooking efficiency and mortality potential of largemouth bass (Micropterus salmoides) captured on circle hooks and octopus hooks

We compared the injury rates, hooking efficiency, and mortality potential of circle hooks and the more conventional octopus hooks for largemouth bass (Micropterus salmoides) captured on minnows in central Illinois. Fish captured on circle hooks (N = 125) were hooked less deeply, exhibited less bleeding, and were more easily removed from the hook than were those captured on octopus hooks (N = 134). The majority of fish captured using both hook types were hooked in the upper lip. Mortality rates were uniformly low for both hook types (circle, 5.1%; octopus, 6.6%). Fish that were identified as potential mortalities were typically hooked deeply in a vital organ or tissue (i.e., heart, gullet, gill arch), exhibited substantial bleeding, and were difficult to remove from the hook. No size-selective trends were noted among hook types, nor were there any differences in total length among mortalities and survivors. Capture efficiency for circle hooks was half that of octopus hooks. Our results suggest that circle hooks do provide some minimal conservation benefits relative to conventional octopus hooks despite having similar mortality rates.