Fate of deep-hooked white-spotted charr after cutting the line in a catch-and-release fishery

Abstract

Using wild white-spotted charr ( Salvelinus leucomaenis) as a model, we investigated the effects of cutting the line and leaving the hook embedded in deeply hooked fish in a multiple catch-and-release experiment. Ten fishing episodes involving 415 tagged fish (fork length range: 96–311 mm) were conducted at weekly intervals. A total of 735 captures (1.8 times per fish), 88 captures were deep-hooked and released by cutting the line. Eleven of the fish were deeply hooked twice, and released by cutting the line in both instances. After the experiment, 93.5% (72/77) of the deep-hooked fish were recaptured, indicating that the survival rates of fish released by cutting the line are sufficiently high to be encouraging. Of the 82 hooks in the 72 fish sampled that were deep-hooked and released by cutting the line, 27 (32.9%) hooks had been evacuated. The hooks remaining after cutting the line in earlier fishing episodes tended to be corroded or had been evacuated. Logistic regression analyses showed that the probability of hooks being uncorroded and remaining in a charr gut decreased with time. The estimated average time before a remaining hook started to corrode was 22.1 ± 22.7 days after cutting the line and the average time to hook evacuation was 53.3 ± 36.3 days. Our study demonstrated that cutting the line is an effective release method for deep-hooked fish under natural environmental conditions.