Parks and Wildlife stocks tiger muskies in Shadow Mountain Reservoir

Officials hopeful tiger muskies could turn Shadow Mountain into a destination fishery.

Tiger muskies have a unique look to them with their long snout and dark vertical markings
Emily Gutierrez/Sky-Hi News

There’s a new fish in Grand County – 13,500 of them actually. It is the tiger muskie. The 7-9 inch fingerlings were released Sept. 14 into Mountain Shadow Reservoir.

Tiger muskies have never been stocked before in Grand County and the process to get these little fish into water here has been a long process for Jon Ewert, an aquatic biologist with Colorado Parks and Wildlife, and his team.  

Shadow Mountain Reservoir has a surface area of 1,337 acres and an average depth of 13 feet with a maximum depth of 37 feet, which perfectly suits the tiger muskie, according to a proposal submitted by Jon Ewert, Jesse Lepak and Lori Martin.

Tiger muskies are a sterile hybrid fish bred from northern pike and muskellunge also known as muskies. The fry were transported from fish hatcheries in Nebraska and Pennsylvania to a fish hatchery in Wray, Colorado. One of the reasons for their long journey is simple: Colorado isn’t home to muskellunge. So, Colorado Parks and Wildlife relies on coordination with other states in order to stock these fish. 

Recently, about 13,500 tiger muskies were released by hand into Shadow Mountain Reservoir.
Emily Gutierrez/Sky-Hi News

On Sept. 14, a hatchery technician drove the 13,500 tiger muskies from Wray to Grand County. After their five-hour trip, the fish were released into Shadow Mountain Reservoir by hand to meet their new roommates, the white sucker.  

Species management

The reservoir has a huge white sucker population. Colorado Parks and Wildlife believe the white suckers were inadvertently or illegally introduced through the use of live bait. The white suckers have outnumbered any other fish in the area, including brown trout. In the agency’s fishery surveys, white suckers have comprised 70% of catches in Shadow Mountain Reservoir, despite stocking trout and other fish.

Tiger muskies are expected to help control the white sucker population by eating them in Shadow Mountain Reservoir. They are piscivores, meaning they eat fish smaller than them. The white suckers are the biggest fish in the reservoir by size and aren’t eaten by trout which are smaller on average.

White suckers are not considered a desirable fish by many anglers, and more desirable fish have to compete with the white suckers for resources like food and habitat.

As a result, Parks and Wildlife believed that a change in fishery management was due.

About 5,400 of these fish were tagged, and the data allows Colorado Parks and Wildlife to assess their movements, survival rates and distribution post-stocking.
Emily Gutierrez/Sky-Hi News

In other Colorado waters the white sucker population has been successfully controlled through the tiger muskie. However, since this fish had never been stocked before in Grand County there were a lot of boxes that had to be checked to minimize any potentially harmful effects.

Current stocking of all salmonid species will cease and the lake will not be managed as a trout fishery, according to Ewert. Parks and Wildlife’s research has shown that tiger muskies will eat these other stocked fish before controlling the white suckers, and officials are trying to maintain the suckers as the only significant prey item available. 

As for predators, these young tiger muskies have to watch out for birds of prey like osprey. If just 10% of these young tiger muskies reach adulthood, they could make great sports fish for anglers.

Potential for trophy fish

Grand County has many other fishing opportunities, but with this one being unique, it could bring in a new angler demographic to Grand County.

Tiger muskies are a highly sought after sport fish species by anglers. They are a notoriously challenging to catch when they reach adulthood because of their large size and fickle feeding habits. Shadow Mountain Reservoir now has the potential to become a destination fishery.

Statewide fishing regulations will apply and the daily bag and possession limit is one tiger muskie that is at least 36 inches in length. The muskies stocked in 2023 have the potential to grow to 36 inches by 2029, according to Ewert. 

Some have worried that these predatory fish will affect Grand Lake because of the connecting channel between Grand Lake and Shadow Mountain Reservoir. All fish are able to freely pass through the two lakes by swimming through the channel. However, the two bodies of water have very different properties. Shadow Mountain Reservoir is much shallower, which is the preferred habitat of tiger muskies. Because of this, Parks and Wildlife expects the movement of tiger muskies into Grand Lake is of minimal concern for Grand Lake’s salmonids. 

Shadow Mountain Reservoir in Grand County connected the Colorado-Big Thompson project and serves as the link between the waters of Lake Granby and Grand Lake.
Emily Gutierrez/Sky-Hi News

Ewert has envisioned the release of these fish for quite some time, so seeing this project come to fruition was a big moment for the Grand and Summit counties’ aquatic biologist. He hopes that in the future, anglers who seek a challenging fish can come to enjoy the tiger muskies.

For now, these tiger muskies will need some time to reach their full potential, but don’t feel shy about saying hello to the newest members of the community.

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