Ben Swiggle and a team of fish biologists from the Colorado Division of Wildlife were in town this week to study the fish population in the St. Vrain River. The team used a shore based electrofishing unit (the fish are shocked and then collected in nets) to determine the population, species, size, density, and biomass of the fish in a dozen different pools along the river.
They are also clipping fins (different fins for different parts of the river), inserting PIT tags (a
small ID chip, similar to ones for dogs and cats, which will record length and weight data) so they can track information about movement and migration, and the possible barrier potential certain man made structures in the river. They are also interested in building a database about the effects that angler harvest, in-stream habitat, and flow dynamics have on the survival rate. In addition, the team will also be stocking approximately 600 Hofer/Rainbow 8” trout in the sampled pools.
The long-range plan is to come back three times next year: twice just prior to snow run-off (May/June), and again just after run-off (late June/early July). The pools they will be studying are: downstream from the kayak park at Black Bear Hole to above Bohn Park on the South St. Vrain, and above Planet Bluegrass on the North St. Vrain, including the holes in the Meadow Park area of the river. This is all a result of the “Catch and Release” statute that was enacted by the Town of Lyons in an effort to revitalize the sport fishing potential in town.