Cuttbows for 11-Mile Reservior
The week of 17 August, 2015 CMCTU pulled together a sizable volunteer team of the Southern Colorado Greenbacks, the Collegiate Peak Anglers, Project Healing Waters and CMCTU folks to support Jeff Spohn the Colorado Parks and Wildlife’s aquatic biologist for the upper South Platte basin. We were working to support Jeff at CPW’s Mount Shavano Fish Hatchery near Salida.
Our task that August week was to enable the identification the two populations of fish by clipping pectoral fins. The team finished clipping all ~60,000 trout by lunch on Wednesday, 2 1/2 days earlier than expected.
Jeff and CPW are conducting an experiment in 11-Mile Reservoir using cuttbows (a hybrid cross of a rainbow and cutthroat trout). The goal of the experiment is to improve fishing both in the reservoir and during the spring spawning migration in the Dream Stream. The experiment involves stocking two groups of cuttbows; one is normal (diploids) and the other sterile (triploids). In theory the triploids will grow faster and larger than the diploids. CPW will then monitor fish catches in the reservoir and during the spring run up the dream stream over the next few years to compare size differences and catch ratios. The experiment is intended to involve several years of stocking these two groups of cuttbows. At the CMCTU January members meeting Jeff discussed issues of northern pike and their sweet tooth for stocked trout, and the presence of Whirling Disease in the Dream Stream that kills essentially all the young rainbow, cuttbow and cutthroat trout that hatch after the spring spawn. So stocking is essential for the spring spawning run valued by so many anglers. And, stocking fish that are too large for the majority of northern pike to eat is a good plan. CPW has learned that 6-inch fish are treats, but 10-inch fish have a ‘decent’ chance at survival. FYI, it turns out that the local brown trout in both the reservoir and the Dream stream are wild, and have been since the 1980’s!
‘Our’ cuttbows were to be stocked into 11-Mile Reservoir in February after they had grown to about 10-inches. It also turns out that there is little demand to stock trout in the middle of the winter, go figure, so it makes it easier on the hatchery crew. So, on a cloudy February day Allyn, Rick and I, GoPro’s in hand, met the team from the Mt Shavano Hatchery to stock the last 11,000 of 60,000 clipped cuttbows through the ice. While CPW understands how trout behave during stocking during the spring, summer and fall, there is no information on trout behavior as they are stocked through the ice in winter. From our video it looks like there were three different behaviors. The first and smallest group made a quick exit to deep water. The second and largest group huddled together in a tight ball on the bottom right below the hole. The third group looked curious and swam around wondered what just happened, or maybe there were hoping the CPW crew would feed them? While we kept looking through out the 30 minutes of stocking, we never saw a northern…