Lake DeSmet salmon growing quicker than predicted
Yes – you heard right - a new species was added to Lake DeSmet. About 40,000 fingerling kokanee (3 -4 inches) were stocked in April 2019. Kokanee are landlocked sockeye salmon that live mostly off shore in lakes and filter feed in the water column on small crustaceans called zooplankton. These zooplankton are at the base of the food chain and eat phytoplankton or algae that live in the open water.

Biologists surveyed zooplankton densities over the summer and the numbers indicated the kokanee should grow well. In fact, two kokanee that were 7 inches long, fat, and sassy showed up during our fall gill net survey! They were not expected to be large enough for capture with the nets until spring 2020. It was a great sign that good things are to come.

The rainbow trout fishery at Lake DeSmet continues to struggle. Gill net catch rates remained low in 2019, aligned with a steady downward trend since 2016. The eagle lake strain of rainbow trout was very popular at DeSmet for decades, particularly with shore anglers because they were known for running the shoreline in the spring.

Game and Fish has been marking Eagle Lake rainbows before they are stocked and have seen very, very few of them during our gill net surveys. In addition, only a single eagle lake rainbow was observed when 425 anglers were interviewed during a creel survey in 2019. Most of the rainbow trout caught at DeSmet now are “fall strain,” which were bred to spawn in a hatchery during the fall. Fall rainbows are performing better but not good enough yet to bring the fishery back to the glory days.

Big walleye, lake trout and brown trout are still common at Lake DeSmet. Although these fish challenge the rainbow trout fishery, they provide excellent opportunities for a trophy fish!
By Gordon Edwards, Sheridan Regional Fisheries Biologist. This story was orginally featured in the 2020 Sheridan Region Angler Newsletter. Read the entire newsletter online.
Sheridan Regional Office - (307) 672-7418

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