Rainbow trout (Oncorhynchus mykiss) production dynamics and relations withabiotic factors in two southern Appalachian mountain streams

Rainbow trout (Oncorhynchus mykiss) annual production was estimated over tw o years in Laurel Branch and South Fork Citico Creek, Tennessee. Both strea ms are softwater, second order streams of the southern Appalachian Mountain s with low inherent productivity (alkalinity <100 mu eq.L-1 or 5 mg.L-1 as CaCO3). Annual production over the two years averaged 12.4 kg.ha(-1) in Lau rel Branch and 6.2 kg.ha(-1) in South Fork Citico Creek. The majority of an nual production (77%) occurred during the December-April period in Laurel B ranch and was dominated by age-2 trout (44%). Though lower overall than Lau rel Branch, annual production in South Fork Citico Creek was also dominated by age-2 trout (47%) but was more evenly distributed throughout the year. Seasonal mean flows and water chemistry measures were related to production and growth rates of age-1 and age-2 trout but not age-0 or age-3 trout. An nual production estimates represented the lowest reported values for rainbo w trout and were similar to regional estimates for brook trout (Salvelinus fontinalis). Findings suggest that trout production in these streams is bel ow worldwide averages for infertile streams and may be related to abiotic f actors which may in effect regulate salmonid production in these streams an nually.