Effects of catch-and-release angling on growth, survival and catchability of white-spotted charr Salvelinus leucomaenis in wild streams

Abstract

We examined the effects of catch-and-release angling on the growth, survival and catchability of white-spotted charr Salvelinus leucomaenis in four wild streams in northern Japan. Investigations were made twice at each stream. We angled fish with live bait and caught fish using electrofishing as controls. Angled and control fish were measured for fork length, marked individually and released. Fifty days later, we angled and caught by electrofishing again. A total of 282 angled fish and 376 control fish had fork lengths of 80.5 to 282.5 mm. Hooking mortality within a few minutes was 6.7%, which agreed well with previous data by studies of catch-and-release mortality. There was no significant difference in standardized growth rate between angled fish and control fish. The recapture rates of angled and control fish were 77.9 and 74.2% respectively, suggesting that the survival rate of angled fish is not lower than that of control fish. No significant difference in catchability was found between angled fish and control fish. The results show no evidence that catch-and-release angling affects growth, survival and catchability. We conclude that catch-and-release angling is effective to sustain white-spotted charr populations.