The tiger muskie, Esox lucius X E. masquinongy, is a hybrid species; a cross between the northern pike and the muskellunge. Tiger muskie have recently been stocked into several Utah waters, including Pineview Reservoir, Newton Reservoir, and Johnson Reservoir. Because the tiger muskie is a hatchery-produced hybrid, it does not occur naturally anywhere in the world.
The tiger muskie has been a boon to Utah fisheries management. Tiger muskie grow to be very large, and they are extremely effective predators. The tiger muskie's predatory skills have enabled it to drastically reduce populations of stunted perch and other panfish in several Utah waters. Remaining panfish are able to grow to larger sizes, which pleases anglers. Additional benefits from tiger muskies stem from the fact that tiger muskies are sterile. Because tiger muskies do not spawn, the Utah Division of Wildlife Resources can closely control the number of tiger muskies in a lake at any one time. Also, because tiger muskies do not put any energy into reproduction (such as energy for egg production, finding a mate, and so on), they grow more quickly than they otherwise would.
The tiger muskie is a "lie-in-wait" predator that will often stay hidden in weed beds until a fish or other prey item moves into range. The tiger muskie then lunges out of its hiding place to grab and devour its prey.