Effect of Trophy Regulations and Reservoir Discharge on a Population of Stocked Brown Trout in a Large, Southeastern United States Tailwater

Reservoir tailwaters can be an important resource for developing quality trout fisheries, especially when managed with special regulations. The objective of this study was to evaluate the effectiveness of a 508-mm minimum-length limit and a 1 fish day-1 creel limit on increasing abundance and size of the brown trout (Salmo trutta) in the Cumberland River below Lake Cumberland, Kentucky. Annual stockings of catchable-sized brown trout remained relatively stable throughout the study at approximately 31,000 fish (503 fish km-1). The purpose of the new regulations, which did not include gear or bait restrictions, was to increase the numbers of quality (381-507 mm total length [TL]) and trophy-size (≥508 mm TL) brown trout in the 121-km tailwater. A significant increase in brown trout electrofishing catch-per-unit-effort (CPUE) was observed across years for small (< 381 mm TL), quality, trophy-size, and all sizes combined brown trout. The trophy regulations resulted in an increase in CPUE of all sizes of brown trout, including trophy-size, in the tailwater without any observed negative density-dependent impacts to brown trout growth or condition. Creel surveys showed that the management objectives of doubling the brown trout size structure of ≥381 mm TL and ≥508 mm TL in the angler catch were more than exceeded. Annual reservoir discharge was positively related with warmer water temperatures and lower dissolved oxygen in the tailwater. There was a negative relationship between both brown trout growth and condition versus annual discharge from the reservoir.

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