In 2021 the Wyoming Game and Fish Department discovered yellow perch in Saratoga Lake. Yellow perch are not native to the upper North Platte River watershed, and their presence in Saratoga Lake is the result of an illegal stocking. The department takes illegal introductions seriously because of the potentially detrimental impacts to Wyoming’s natural resources.

Saratoga Lake is managed as a trout fishery and is not stocked with any cool- or warm-water fish, including yellow perch. Yellow perch could escape Saratoga Lake and make their way into the upper reaches of the North Platte River drainage. They are likely to disperse downstream to other waters in the watershed – including Seminoe, Pathfinder, Alcova, and Gray Reef reservoirs, and the Sweetwater and Medicine Bow rivers – where they could do irreparable damage to the sport fisheries and native fish species.