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Local Volunteer Support And Engagement Helps Boost Rainbow Trout Production In Williams Lake Near Salmon

Williams Lake Fishery Study, Part 2

Welcome back to our blog series covering fisheries activities happening on Williams Lake in 2023. If you haven’t read part 1, you can find that here. As a brief recap, Salmon Region fisheries staff operated a fish weir on the inlet creek to Williams Lake this spring to gauge the health of the Rainbow Trout spawning population. This was the first of multiple surveys to be conducted on the lake this year as concern about the fishery has arisen recently due to an increase in the abundance of Bridgelip Suckers. While the weir was an excellent tool to help IDFG monitor the current Rainbow Trout population, it was historically used to facilitate juvenile trout production.

Instream incubation station on the Williams Lake outlet.

Although a small instream incubation system (shown above) is the only functional remnant as of 2023, there once was a small hatchery operation located on the Williams Lake outlet. The facility could accommodate thousands of fertilized eggs collected from fish trapped at the weir and was even outfitted with multiple small instream raceways that were used to raise juvenile Rainbow Trout to the fry stage. Fry hatched at Williams Lake were generally transferred to a federally managed hatchery in Salmon (no longer in operation) or other IDFG hatcheries before being stocked into a variety of Idaho lakes, including Williams Lake. Though large-scale trapping and rearing of Williams Lake Rainbow Trout ceased around the 1980s, a similar effort began in 2002 that engaged local anglers and homeowners to increase trout production.

Backpack electrofishing to collect adult Rainbow Trout.

To help increase the number of Rainbow Trout in Williams Lake, IDFG along with many gracious volunteers conducted an annual spring egg-take on Lake Creek from 2002 to 2015. The crew would utilize backpack electrofishing to capture adult Rainbow Trout. Trout were then spawned streamside, and the fertilized eggs were taken to the incubation station at the outlet. The eggs incubated for about eight weeks before they were ready to be stocked at the fry stage. Although this may sound redundant because the fish are moving upstream to spawn naturally, it had been previously reported that Rainbow Trout production in Williams Lake is limited by the amount of available spawning habitat in the inlet. Thus, this was the perfect collaborative opportunity to give the Rainbow Trout population a boost.

Streamside egg fertilization.

In 2023, IDFG and multiple volunteers that live at the lake decided to revive this collaborative effort. Fisheries personnel and volunteers conducted the egg-take and fertilization during mid-May and transferred approximately 8,000-10,000 eggs into the outlet incubation system. Since it had not been used in quite some time, a smaller batch was reared this year. However, we are happy to report that after the diligence put in by volunteers watching the eggs daily, survival to fry stage was high. The fish were then stocked into Lake Creek to grow naturally at the end of June.

Rainbow Trout fry ready for stocking.

Although these hatchery-reared fry were too small to tag, we can still track the success of the program using new genetic techniques. Genetic samples were taken from each of the adult trout used for the streamside fertilization, in hopes that fish sampled from the lake in a few years can be traced back to their ‘parents’. Overall, the revitalization of the egg-take was certainly a success. Salmon Region fisheries staff extent a large thank you to the volunteers and homeowners at the lake for their support and dedication to improving the fishery. Remember, this is just part 2 of the 2023 Williams Lake fishery assessment, so be sure to look out for the next blog! In the meantime, if you catch a fish with an orange T-bar tag, please be sure to report at tag.idaho.gov or use the phone number listed on the tag!

Fertilized Rainbow Trout eggs in incubation station.

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