Fulton's body condition factor K correlates with survival time in a thermal challenge experiment in juvenile Lahontan cutthroat trout (Oncorhynchus clarki henshawi)

Thermal tolerance was measured in an experimental setting using seven full-sibling family groups of hatchery reared Lahontan cutthroat trout (Oncorynchus clarki henshawi). Body weight and fork length were measured and Fulton's body condition factor (K) was estimated for each individual. Heritabilities were moderately high for body weight (0.50), upper temperature tolerance (0.44), and K factor (0.50). Estimates of genetic and phenotypic correlations between upper temperature tolerance and K factor were 0.53 and 0.41, respectively. K factor may be an indicator as to the ability of an individual to survive periods of increased water temperature during the summer months.