Upper North Crow Reservoir now contains a new predator, according to the Wyoming Game and Fish Department.  If you are a dedicated and persistent angler, you might be able to catch one.

About 650 tiger muskies were deposited by the Wyoming Game and Fish Department into Upper North Crow Reservoir last week.  Their presence is designed as a biological control that will reduce the numbers of white and longnose suckers in the reservoir.

The tiger muskellunge (known as the tiger muskie) is the hybrid offspring of the true muskellunge and the northern pike.  It is a carnivorous fish that has been used in other Wyoming waters to control undesirable or overpopulated fish species.  About 1,000 more tiger muskies will be stocked at Upper North Crow Reservoir in 2016 and 2017.

The “very abundant” population of longnose suckers and white suckers “has had negative impacts on stocked game fish,” according to Laramie Region fish biologist Steve Gale.  “The suckers compete with the game fish for food and other resources.  As a result, growth of rainbow trout and grayling has been slow,” says Gale.

To help control the sucker populations, Splake– which sometimes feed on white suckers– were stocked in North Crow Reservoir each year from 1999 to 2014.  Trap netting was also implemented from 2006 through 2010 in an attempt to reduce the sucker numbers, but had little effect.

“The sucker population continues to increase and if left unchecked will continue to impact fish stocking and angler success,” said Gale.  “Although longnose and white suckers are native to the drainage, their overall abundance and distribution throughout the state is secure, so we felt comfortable attempting to reduce their population in Upper North Crow Reservoir to improve angler success.”

In order to push the tiger muskies to feed on suckers, trout stocking in Upper North Crow Reservoir will be discontinued.  However, over the course of several years, “as the sucker population decreases we will phase out the tiger muskies and restock game fish,” Gale said.

At present, the tiger muskies are small– between six and eight inches in length– but should reach the legally harvestable size of 30 inches within a few years.  Once they become effective predators, it will take a couple of years more for them to impact the sucker population.

Fish managers say that the tiger muskies are difficult to catch, but “will make a nice trophy fish when they reach the large sizes we are expecting them to obtain at Upper North Crow Reservoir,” according to Gale.

Anglers in pursuit of trout need not worry.  Crystal and Granite reservoirs in Curt Gowdy State Park will continue to be stocked with trout each year.