October 19, 2022 |

It’s safe to go in the water again. Saratoga Lake is free of rotenone and open for use again, although all the fish are gone until next year. The number of yellow perch found in the lake after last month’s fish kill-off surprised even the Wyoming Game and Fish Department.

The WGFD took the drastic step of killing all the fish in the lake when invasive yellow perch were found in it last year. If the yellow perch had escaped, they had the potential to harm the critical fisheries downstream in the North Platte River, such as the Miracle Mile.

To eliminate the perch, WGFD used a toxin called rotenone. The chemical suffocates gill-breathing organisms by interrupting their ability to uptake oxygen from water. Last month’s treatment took about a week to complete. It successfully killed all the fish in the lake.

After treating Saratoga Lake with rotenone, WGFD collected the dead fish and buried them in pits dug along the eastern shore. Bobby Compton, regional fisheries supervisor for Wyoming Game and Fish, said they don’t know exactly how many fish they pulled out of the lake, but that most of them were one specific species—white suckers.

Pictured above: Photo of Saratoga Lake courtesy WGFD.

White suckers are native to the area and can be found in just about all bodies of water. Finding a lot of suckers was no surprise. Compton said they far outnumbered the other types of fish in the lake.

Wyoming Game and Fish didn’t think there would be as many yellow perch as they found. Compton said white suckers were the most plentiful, but trout and perch were almost equal in numbers.

After the rotenone treatment, Bobby Compton and his team conducted weekly tests with canary fish to see if the toxin was still active in the water. Compton said the canary fish didn’t die, meaning the rotenone has dissipated.

Gill nets came up empty on Monday. WGFD are confident that all the fish have been removed.

With the rotenone gone, the lake is now safe to use again. The Saratoga Lake Public Access Area had been open for a few weeks, but WGFD had posted signs advising the public not to go in the water. Compton said those signs have been taken down.

The lake is open for recreation. However, the lack of fish will limit what people can do there. Boating is still an option, but with temperatures dropping, it is unlikely that anyone would want to swim in the lake. Compton advised against taking the polar bear plunge.

Wyoming Game and Fish have successfully completed their fish kill-off at the Saratoga Lake. They will begin to stock fish in the spring, bringing the lake back up to its pre-rotenone levels, before the yellow perch were introduced. The 2022 Ice Fishing Derby has been canceled, but, as long as no more invasive fish find their way into the lake, the 2023 Derby should happen.

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