Harvest, Survival, Growth, and Movement of Five Strains of Hatchery-Reared Rainbow Trout in Virginia Streams

Abstract

Catchable-size (minimum length 17.8 cm) rainbow trout (Salmo gairdneri) of five genetically distinct strains were harvested by anglers at significantly different rates when the fish were stocked into four put-and-take trout streams in southwestern Virginia. Fish from Standard Winter (SW) and Ennis (EN) strains were caught easily; 85.7 and 93.2% of their respective total harvests occurred during the first 2 d of the fishing season. Sand Creek (SC), Fish Lake (FL), and McConaughy (MC) strains were harvested more uniformly over the first 3 weeks of fishing; 64.6, 58.4, and 43.4% of their respective total harvests occurred during the first 2 d. The average total harvests of SC (47.7%) and SW (46.7%) strains were similar and ranked highest among the five strains; however, no strain showed statistical superiority in all four streams. Harvest of the MC strain was consistently and significantly lower than the other four strains within each stream and averaged 25.6%. Average harvests of FL (42.8%) and EN (39.5%) strains were intermediate. Significant environmental (stream) influences and genotype-environment interactions were evident. No significant differences in tendency to move downstream were found. Fish of the EN, SW, and SC strains were significantly more vulnerable to fishing with bait (versus artificial lures) than fish from FL and MC strains. Differences in natural mortality rate, growth, and downstream movement among strains in a fifth, unfished, stream were not significant. Condition factor (K) decreased significantly for all five strains in an unfished stream. The MC strain appeared to be poorly suited for put-and-take streams, while SW and SC strains performed about equally well and are worthy of further evaluation in stocked stream environments. Managers should select strains (other than SW or SC) for future evaluation in put-and-take streams based on hatchery performance, but should give consideration to potential masking or damping effects of natural environments.