Sheridan -

Muddy Guard #2 in Johnson County has been restocked after the fish population was removed in fall 2022 to address an overpopulation of longnose suckers. 

Abundant longnose suckers have challenged the stocked rainbow fishery for years through competition for aquatic insect and crustacean forage. Tiger trout, a sterile hybrid, were stocked in recent years to reduce the sucker population. Small tiger trout feed on aquatic insects but shift to eating mostly other fish, like young suckers, when they are larger.

Though the sucker population had declined in recent years, the body condition and growth of rainbow trout did not improve.  Tiger trout competing with suckers for food also failed to grow large enough to begin controlling the suckers in earnest.  

Sheridan Region fisheries biologists worked with the North Fork Irrigation District, landowners, the State Engineer's Office, and the Wyoming Water Development Office to drain the reservoir as low as possible by late 2022.  Last November, biologists chemically treated Muddy Guard #2 with rotenone to remove all fish. The plant-derived chemical served its purpose and naturally degraded over the winter.  A follow-up survey in March confirmed the suckers were eliminated.

In May, the reservoir was stocked with 2,200 catchable-sized Eagle Lake rainbow trout from Wigwam Hatchery. Tiger trout will also be restocked and some wild brown trout will enter from the supply ditch.  

Longnose suckers are present upstream in the drainage and will likely return to the reservoir.  However, the trout will have a head start and predation by these faster growing, larger trout should keep the suckers  at a lower level than before treatment.

The project’s goal is to provide a quality trout fishery with a moderate to high angler catch rate and provide ample harvest opportunity.  Muddy Guard #2 is an alternative to the trophy fishery at Muddy Guard #1, where harvest is restricted.  Stocking of rainbow and tiger trout will continue at Muddy Guard #2 and fisheries biologists will conduct regular surveys to evaluate the impact of these management efforts on this popular fishery. 

- WGFD -