Why stock sterile fish

In some cases, IDFG does stock fertile, diploid fish which can reproduce. Here our goal may be for the stocking to supplement the population and contribute to the fishery's recruitment. Mackay Reservoir is an example of this. Mackay Reservoir, like a lot of western reservoirs, goes through large, seasonal fluctuations in water level. This can lead to recruitment problems, so we stock fertile fish to mitigate this bottleneck. In other cases, such as Henrys Lake, we will stock fertile Yellowstone Cutthroat Trout that naturally want to migrate into spawning tributaries to spawn in order to boost natural production in Henrys Lake tributaries and to continue to provide a viable egg source to fill hatchery requests for not only Henrys Lake but several other waters where Henrys Lake Cutthroat Trout are stocked throughout the state. So, while IDFG often stocks sterile fish, there are many cases where stocking fertile fish better aligns with our fisheries management objectives.