Impacts of hook anatomical location and the use of de-hooker devices on survival and reflex impairment of bogue (Boops boops), in Catch-and-Release fishing

Abstract

Catch-and-Release (C&R) is a widespread practice in recreational fisheries in which fish are released alive after capture. Its effectiveness, however, depends on maintaining high post-release survival to ensure management and conservation benefits. This study evaluated post-release mortality in bogue (Boops boops), a common target species in Mediterranean and Atlantic temperate fisheries, examining its relationship with several explanatory variables, with particular emphasis on the effect of de-hooker devices. Results indicated a post-release mortality rate of 20.4% (95% CI: 13.5-29.4%), largely associated with deep-hooking events. Mortality was significantly lower when hooks were manually removed from shallow locations (2.5%; 95% CI [0.1-14.7]) compared to line-cutting (29.4%; 95% CI [15.7-47.7]) and de-hooker use (32.4%; 95% CI [18-50.6]) in deep-hooking scenarios. No significant differences in mortality were detected between line cutting and the de-hooker treatment, suggesting that de-hookers perform similarly to line cutting in deeply hooked fish. Reflex impairment, especially loss of orientation, was identified as a strong predictor of mortality and was most frequent in deeply hooked individuals. Bleeding was also significantly associated with mortality, and the combined presence of bleeding and disorientation consistently resulted in lethal outcomes. Neither reflex impairment nor bleeding differed significantly between fish treated with de-hookers and those subjected to line-cutting, indicating that de-hookers do not mitigate physiological damage once deep-hooking has occurred. This study provides the first evidence that orientation impairment reliably predicts post-release mortality in bogue. Overall, preventing deep hooking is the most effective strategy to minimize mortality, while de-hookers provide survival outcomes similar to line-cutting in deeply hooked fish.