Pesky perch to perish

The Wyoming Game and Fish Department (WGFD) will be holding an informational meeting in Saratoga on June 9 regarding their plans to address illegally-stocked yellow perch in Saratoga Lake.

In 2021, the WGFD discovered yellow perch had been introduced to Saratoga Lake, which is maintained by the state department as a trout fishery. During the 39th Annual Saratoga Lake Ice Fishing Derby, a number of the non-native fish species were caught by ice anglers over the weekend (see “Problematic Perch” on page 1 of the February 2, 2022 Saratoga Sun). According to Chance Kirkeeng, the WGFD Laramie Region Fisheries Biologist, when the yellow perch were first discovered during sampling of Saratoga Lake in 2021 they ranged in length from two to nine inches.

Due to the fish not being native to Wyoming nor the North Platte River, WGFD concluded illegal stocking was the only way they could have been introduced to Saratoga Lake. While they are a popular sport fish, Kirkeeng said it was unlikely the yellow perch would create a quality fishing experience at Saratoga Lake judging from experiences in other Wyoming lakes. 

According to a press release from the WGFD, the meeting in Saratoga will consist of Laramie Region fisheries managers discussing the history of management of Saratoga Lake. They will also discuss the plan to kill all of the fish in Saratoga Lake in September using rotenone.

Rotenone—which is derived from the roots of certain members of the bean family in South America—is a natural product. It has been used in the past by fish managers to remove undesirable fish in many places, according to the press release. While it is lethal to organisms with gills, it is non-lethal to humans, pets, other wildlife and livestock. Rotenone works by disrupting the oxygen uptake within the cells of gill-breathing organisms.

In preparation of the rotenone treatment, water levels at Saratoga Lake have been lowered, though there are no plans to drain the lake completely.

“The lake will continue to lose water through evaporation throughout the summer, which will allow the rotenone to be more effective,” said Bobby Compton, fisheries supervisor in the Laramie Region. “The inflow and outflow of the lake have already been turned off.”

Because of the lower lake levels, people should expect different conditions at Saratoga Lake than in the past. These include challenges for boating and muddy shorelines. Algal blooms may also be more prolonged and intense.

“One of the main reasons we are treating Saratoga Lake is because of the risk of spread throughout one of our major river drainages,” said Alan Osterland, Game and Fish chief of fisheries. “We can’t take the risk for the good of the entire State of Wyoming and we need to do all we can to stop the fish from dispersing.”

If left unchecked, the presence of the yellow perch in Saratoga Lake would have likely proven detrimental to other bodies of water in the North Platte River drainage. These include Seminoe, Pathfinder, Alcova and Gray Reef reservoirs and the Sweetwater and Medicine Bow rivers. Once in those bodies of water they could damage the sport fisheries and the native fish species.

The use of rotenone to kill all of the fish in Saratoga Lake is expected to occur in September. After the lake has been killed, WGFD will then rebuild the trout fishery.

“This public meeting is your opportunity to learn about the rotenone project and what to expect,” said Compton. “We plan to update the public throughout the project as well and continue conversations about how we can rebuild Saratoga Lake.”

While the water levels at Saratoga Lake are becoming lower, anglers are still encouraged to aid WGFD by harvesting as many yellow perch from the lake as legally allowed. These include fish which are smaller than anglers might normally choose to keep. The statewide regulation of 50 yellow perch in the creel and possession is currently in place. All kept fish should be cleaned and not wasted.

Anglers are also reminded it is illegal to move fish from one body of water to another in Wyoming with penalties up to $1,000.

The public meeting discussing the Saratoga Lake treatment begins at 6 p.m. on June 9 at the Platte Valley Community Center (210 W. Elm Street) in Saratoga.