Hatchery Performance Attributes of Nipigon, Assinica, and Iron River Strains of Age-0 Brook Trout

Abstract

The fingerling hatchery performance attributes of brook trout Salvelinus fontinalis of Lake Nipigon origin were compared with those of domesticated (Assinica) and nondomesticated (Iron River) strains of this species in a 150-d laboratory experiment. Despite similar initial sizes, the final mean length and weight of the Assinica strain (134.9 mm and 26.3 g) were significantly greater than those of the Nipigon (112.6 mm and 13.6 g) and Iron River (111.2 mm and 14.6 g) strains. Specific growth rates differed significantly among strains, with Assinica fish having the greatest mean daily percent increases in length and weight (0.98% and 3.10%, respectively), followed by the Iron River (0.93% and 3.03%) and Nipigon (0.86% and 2.69%) strains. The mean daily absolute rates of growth in length and weight were similar in the Nipigon and Iron River strains but significantly lower than for the Assinica strain. Survival rates and food conversion efficiency estimates were not significantly different among the three strains of brook trout. Relative weight values were significantly greater for Assinica (96.4%) and Iron River (94.0%) fish than for Nipigon (87.0%) fish. Based on these results, we recommend that fingerling Nipigon brook trout be reared more like nondomesticated strains of this species, such as Iron River fish, in hatchery environments.