SEAFWA 2015

Amanda M. Bushon, Jacob M. Rash, A. Powell Wheeler, David L. Yow –North Carolina Wildlife Resources Commission

Apalachia Reservoir is a 445-ha impoundment in western North Carolina that contains suitable trout habitat year-round and Blueback Herring (Alosa aestivalis), an abundant cold-water forage base. As such, the impoundment was a good candidate for experimental put-grow-and-take trout stockings, with the potential to produce a trophy trout fishery. The objective of this four-year study was to determine the appropriate size and species of stocked trout to utilize within Apalachia Reservoir. Beginning in December 2012, the North Carolina Wildlife Resources Commission began stocking Brown Trout (Salmo trutta) and Rainbow Trout (Oncorhynchus mykiss) at two different sizes, 255 and 356 mm mean total length (TL). All trout were marked with visible implant elastomer and coded wire tags prior to stocking to differentiate year and size classes. During 2013 and 2014 gill-net collections, recaptured Brown Trout lengths ranged from 271–585 mm TL (n=30); no Rainbow Trout were collected in gill-net samples either year. Brown Trout recaptured during 2014 and 2015 electrofishing samples ranged in length from 222–594 mm TL (n=49), while Rainbow Trout lengths ranged from 251–498 mm TL (n=98). Preliminary results suggest that Brown Trout are achieving larger sizes at faster rates than Rainbow Trout. In addition, a twelve-month creel survey began in December 2014 to assess angler catch and harvest rates of stocked trout.

David P. Dreves, Jeff R. Ross -Kentucky Department of Fish and Wildlife Resources; Jarrad T. Kosa, U. S. Fish and Wildlife Service

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 one-fish-per-day creel limit on improving the size structure of the brown trout Salmo trutta population in the Cumberland River below Lake Cumberland, Kentucky. 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) and trophy-size (≥ 508 mm total length) brown trout in the 121 km tailwater. A significant increase in brown trout electrofishing catch per unit effort was observed across years for small (< 381 mm), quality, trophy-size trout, and all sizes combined. As brown trout electrofishing and angler catch rates increased over time, no corresponding decrease in growth or condition was observed. Annual reservoir discharge was positively correlated with warmer water temperatures and lower dissolved oxygen in the tailwater. Growth and condition of brown trout in the tailwater were inversely correlated with annual discharge from the reservoir. The trophy regulations resulted in an increase in abundance and larger sizes of brown trout in the tailwater without any observed negative density-dependent impacts.

Amanda M. Bushon, Jacob M. Rash, Christopher J. Goudreau –North Carolina Wildlife Resources Commission

Recreational flow releases were established within Nantahala River Bypass Reach through the Federal Energy Regulatory Commission relicensing of Duke Energy’s Nantahala Project. In 2012–2013, the North Carolina Wildlife Resources Commission, in conjunction with other resource managers, attempted to monitor the influence of recreational flow events on wild trout populations within Nantahala River Bypass Reach and Nantahala Tailwater. Monitoring included temperature loggers, fish population sampling, and fish held in live cages during the flow events. Temperature effects of release events were most pronounced during late summer and fall releases. Densities and standing crop estimates of adult wild trout did not vary substantially among the sample dates; however, age-0 Rainbow Trout were not present during the last sample date at either site. Short-term effects of the releases were not apparent in fish held in live cages. Although recreational releases have the potential to affect wild trout populations, stocking trout in the bypass reach remains a viable management approach.

C. Wood, D. Goodfred, J. Rash, D. Besler –North Carolina Wildlife Resources Commission

Bridgewater Tailrace is a 29-km waterway extending from Lake James to Lake Rhodhiss in western North Carolina. An 18-km reach is classified as Special Regulation Trout Waters by the North Carolina Wildlife Resources Commission (NCWRC) and managed as a put-grow-and-take trout fishery. This reach was stocked each spring from 1996–2008 with 25,000–50,000 fingerling (25–75 mm total length) Brown Trout (Salmo trutta) in an effort to establish a high-quality tailrace fishery. Early results suggested stocking efforts were successful; however, subsequent evaluations from 2003–2009 demonstrated recruitment of stocked fish was highly variable and negatively correlated to water temperature. Recent upgrades to Bridgewater Hydro Station led to a new stocking approach by NCWRC that may ameliorate historical issues. In 2012, the NCWRC initiated a five-year study to evaluate annual stockings of 10,000 advanced fingerling (200–255 mm total length) Brown Trout. Fish were marked with coded wire tags and stocked during late fall after the threat of elevated water temperatures. Preliminary results from 2012–2015 suggest the fishery is improving: catch-per-unit-effort (CPUE; fish/hour) increased and percent contribution of stocked fish is high and consistent among survey years. Four year classes of stocked Brown Trout occur within the fishery; however, age structures indicate elevated mortality between ages one and two. Additionally, CPUE of stocked age-one Brown Trout declined between spring and fall samples within a single year, suggesting elevated temperatures during late summer and early fall continue to impede recruitment into the fishery.

Kevin J. Hining, Jacob M. Rash – North Carolina Wildlife Resources Commission