June 8, 2022 |

Perhaps the biggest casualty of the massive fish kill planned for Saratoga Lake this fall will be the annual Ice Fishing Derby. With no fish in the lake, the 2023 derby will be “put on ice” for a year.

As reported previously, Wyoming Game and Fish plans to treat the lake with rotenone, a broad spectrum insecticide. The decision to kill all of the fish in the lake is a “last resort” response to deal with the illegal stocking of yellow perch there last year.

Allan Osterlund, the chief of fisheries for the state game agency, said the drastic kill-off is being taken to protect trout habitat downstream in the North Platte River system. The treatment will happen in September. Osterlund said the trout fishery will not be rebuilt in time for the popular ice fishing derby in January.


It’s both a fish kill and a buzz kill. January’s event would have been the 40th anniversary of the popular ice fishing derby which brings in 750 or more anglers and their families each year.

The Saratoga Platte Valley Chamber of Commerce hosts the event. Chamber Director Amanda Knotwell said her board of directors is weighing its options for possible alternatives.


Osterlund said that the decision to kill all the fish in the lake to protect downstream fisheries from an explosion of invasive yellow perch all the way downstream to Grey Reef Reservoir was not made rashly. A mix of science, financial calculations and heartbreak has gone into the process.

Pictured above: Winner of the 2022 Saratoga Lake Ice Fishing Derby Trevor Dusza from Carbondale, CO, with a rainbow trout. Length was 23 inches, girth was 13 inches, giving a total of 36 pounds to win this year. Courtesy photo.


Killing off the fish in Saratoga Lake will protect the sport fishing in larger bodies of water like Seminoe. Osterlund said yellow perch produce a lot of eggs. The cool-warm water species doesn’t grow very big in Wyoming’s cold, high elevation lake. They are more of a warm water fish and popular in the Midwest, Osterlund said. They reproduce rapidly though, and biologists are concerned that sheer number of them would compete for food with the sport fish that anglers want to catch.


The rotenone treatment will be applied this September. In anticipation of treating the lake with the insecticide, the lake has been cut off from inflows. Water levels have been dropping already this spring, and will continue to evaporate over the summer.

Osterlund biologists have been “working their pencils” to calculate the correct dilution needed to kill the fish. He said the chance the insecticide might harm other species downstream is minimal.


Biologists say rotenone is lethal primarily to gilled animals. Birds that eat the dead fish will not be affected. Biologists will collect the harvest and conduct soil samples to make sure the treatment worked. Then the process of rebuilding the fishery will begin. The plan is for fishing to return next summer


Osterlund and other officials from Wyoming Game and Fish will hold a public meeting in Saratoga to discuss their plan tomorrow night. The meeting is set for 6 p.m. at the Platte Valley Community Center.

In the meantime, Chamber Director Knotwell is maintaining a positive attitude about the cancellation of the ice fishing derby in January.


Knotwell said the derby was cancelled one other time when the lake was drained because of a parasite. It recovered then, she said, and will this time, too.

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