AGE, GROWTH AND CONDITION OF BROOK TROUT (SALVELINUS-FONTINALIS) FROM AN UNEXPLOITED ALPINE LAKE

The purpose of this study was to provide baseline data on fish populations in the Green Lakes Valley (Colorado Front Range) as part of the long-term ecological research program of the University of Colorado. While the results were site specific, the fish sampled (brook trout, Salvelinus fontinalis) had been unexploited for the past 50 years. Because data from unexploited fish populations are rare, they are presented here for use by fisheries biologists and ecologists who often need to know the potential for fish growth and longevity under unexploited conditions. Fish were sampled with gill nets from Green Lake 3 (GL3) and total length, weight and sex determined. Otoliths were used to estimate age. Females outlived males; the maximum longevity was 13 years. Growth and condition of GL3 brook trout was within the range observed in other studies of the species in western U.S. lakes with one exception. Brook trout from Bunny Lake, California, had a longer life span (24 years), much lower condition and slower growth than GL3 brook trout. These data will be a valuable reference point for those interested in this species in high elevation lakes, especially since the study site will be part of the long-term ecological research network.