Dispersion Patterns Of Hatchery-Reared Rainbow Trout Stocked In A Virginia Mountain Stream

Dispersion patterns of 578 tagged rainbow trout stocked into pool and riffle habitats of Big Stony Creek, Giles County, Virginia, were determined from voluntary tag returns and a creel census of fishermen during the 1979-80 trout fishing season. Twentytwo percent of the trout remained within the original 30 m stocking location; 45 percent of the trout moved downstream whilc 33 percent moved upstream. The median dispersion distance and direction for aU trout that moved beyond tbe initial release sites was 30 m downstream. The majority (75%) of the marked fish were caught within 400 m of the stocking location. There was no significant difference (P > 0.136) between the median distance moved of trout stocked into pools and those stocked into riffles. Three major physical factors (residence time, water temperatures, and stream flow rates) were found to strongly influence stocked trout dispersion. The distance trout moved was directly correlated (R = 0.50, P < 0.001) with the amount of time in the stream. During stream conditions of low water temperatures and high flow rates, trout dispersion increased. Movement of spring stocked rainbow trout was primarily downstream, while movement of faU stocked trout was upstream. Summer stocked rainbow trout showed little movement.

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