Effect of Finclipping on Survival of Sockeye Salmon (<i>Oncorhynchus nerka</i>)

Abstract

A finclip and a chemical (tetracycline) mark were applied, in similar numbers, to hatchery-reared fingerling sockeye salmon (Oncorhynchus nerka). In mark-sampling of returning adults 3 and 4 years after release from the hatchery, numerical comparison of fish with the two marks showed that fewer finclipped fish returned than expected. It was demonstrated that the tetracycline mark did not affect survival and that the difference between returns of fish with the two marks originated in mortality caused by finclipping. The mortality attributed to finclipping was estimated as 39%.