Effects of Floy and Soft VIalpha Tags on Growth and Survival of Juvenile Arctic Char

Abstract

Abstract The Floy FTF-69 fingerling tag and the new soft VIalpha (VI) tag can both be used on small fish (>100 mm and >150 mm, respectively) according to their manufacturers, but information on their use and effect on fish has not been available. In this study, these two tags were compared for one year on wild Arctic char Salvelinus alpinus, parr (lake dwelling), and smolts (100–229 mm) from two small lakes in northern Norway. Comparisons of growth rate, survival, and tag retention were analyzed. In general, VI-tagged smolts grew significantly better than Floy-tagged smolts in the sea. However, the difference was largest for the smallest fish (100–189 mm); for the larger fish (190–229 mm), there was less or no difference. Survival rates in the sea were also significantly higher (11–15%) for the smallest (<170 mm) VI-tagged smolts than for Floy-tagged smolts of the same size; larger VI-tagged smolts (≥170 mm) only survived at a slightly higher (1.5–4.0%) and nonsignificant rate than corresponding Floy-tagg...