Ridgway Reservoir, a popular destination for anglers and boaters in western Colorado, will soon have a new fish species to offer. Colorado Parks and Wildlife (CPW) plans to stock sterile walleye into the reservoir at Ridgway State Park during the spring of 2024.

Why sterile walleye?

Walleye are a highly sought-after sport fish that can grow up to 30 inches and weigh over 10 pounds. They are known for their excellent taste and challenging fight. However, they are also a potential threat to native fish species, especially in the Upper Colorado River Basin, where CPW is working to conserve and recover endangered fish such as the Colorado pikeminnow, razorback sucker, humpback chub, and bonytail.

To prevent walleye from escaping the reservoir and harming native fish, CPW will only stock sterile walleye, which are produced by a special process that makes them unable to reproduce. Sterile walleye have been successfully stocked in other reservoirs in Colorado, such as Pueblo and Chatfield, where they have created exciting fishing opportunities without impacting native fish.

How will walleye affect the reservoir?

CPW aquatic biologist Eric Gardunio said that stocking sterile walleye is part of a larger goal to increase angling opportunities in western Colorado in a way that is compatible with the native species of the Upper Colorado River Basin. “This will diversify the fishery while still allowing us to maintain and accomplish other management goals within the reservoir,” he said.

One of those goals is to sustain a robust forage base for predatory fish, such as rainbow trout, brown trout, and kokanee salmon, which are already present in the reservoir. Walleye will feed on smaller fish, such as yellow perch, suckers, and crayfish, and help control their populations. Walleye will also provide a new challenge and a new option for anglers who prefer to fish for warmwater species.

Another goal is to maintain reproduction and recruitment for brown trout, which are a native species in the Gunnison River Basin. Brown trout are highly valued by anglers for their size, color, and behavior. They can spawn naturally in the reservoir and in the tributaries, such as the Uncompahgre River. CPW will monitor the interactions between walleye and brown trout and ensure that both species can coexist and thrive in the reservoir.

When and how will walleye be stocked?

CPW aims to begin stocking sterile fingerling walleye into the reservoir this spring. The fish will be spawned and undergo the sterilization process at Pueblo Reservoir before being transferred to the Pueblo State Fish Hatchery. CPW plans to stock 30,000 1.2-inch long walleye fingerlings annually, if the sterilization is proved to be successful.

CPW will also construct an escapement barrier on the spillway of the reservoir, which will further prevent sterile walleye and smallmouth bass, another non-native species in the reservoir, from escaping into downstream waters. The barrier will consist of a metal grate that will allow water to flow through but block fish from passing. The barrier will also have a trap that will allow CPW to capture and remove any fish that may try to escape.

What do anglers need to know?

CPW Area Wildlife Manager Rachel Sralla said that CPW is excited to add this new species to the fishery, and looks forward to developing and maintaining this population over the coming years to provide opportunity for multiple angling interests. “Using these sterile walleye really allows us to diversify our fishing opportunities,” she said.

Anglers who want to fish for walleye at Ridgway Reservoir will need to follow the same regulations as other reservoirs in Colorado. Walleye have a bag and possession limit of five fish, with no size restrictions. Anglers can use any legal method of take, such as artificial lures, live bait, or fly fishing. Walleye are most active during low-light conditions, such as dawn and dusk, and can be found near the bottom of the reservoir or along drop-offs and points.

Anglers who catch walleye are encouraged to report their catch to CPW, either by phone, email, or online. This will help CPW track the growth and survival of the stocked walleye and evaluate the success of the program. Anglers can also share their photos and stories on social media using the hashtag #RidgwayWalleye.

CPW also reminds anglers to respect the reservoir and its wildlife, and to follow the rules and regulations of Ridgway State Park. The park offers a variety of amenities and activities, such as camping, hiking, biking, boating, swimming, and wildlife viewing. The park is open year-round, but some facilities may be closed or limited during the winter. For more information, visit the park’s website or call 970-626-5822.