Idaho Fish and Game completes fish survey in the Snake River below American Falls Reservoir

On Nov. 18 and 20, Southeast Region Fish and Game fisheries staff and volunteers put on waders, loaded a drift boat with electrofishing equipment, and surveyed a one-mile stretch of the Snake River from Hatchery Creek to Pipeline Access. During the survey, the crew captured and released 312 rainbow trout, 17 mountain whitefish, 13 smallmouth bass, 11 brown trout, and 8 cutthroat trout. Other fish documented in the survey included Utah chub, Utah sucker, and yellow perch, though these species were not targeted by the survey.

The largest trout captured was a 26.7-inch brown trout. The largest rainbow trout was 22.2 inches with the majority of rainbows measuring between 16 and 20 inches. Rainbow trout were the only species with a large enough sample to estimate abundance. In other words, without biologists finding and counting every rainbow during the survey, the sample size was still big enough to give biologists a good understanding of how many fish use that stretch of river. In this case, fisheries staff estimate that there were about 2,000 rainbow trout in that mile-long stretch of the Snake River during the survey. In fact, this level of abundance is quite typical for Idaho rivers where rainbows are found.