Understanding Steelhead

Idaho: Understanding Idaho's Steelhead Fishery


Written by Will Lubenau, University of Idaho

Now that the snow has started to fly and the weather seems a little bit more like winter, the steelhead encounter rate and catch and release mortality study is wrapping up fall tagging at Lower Granite Dam. As of November 11, 2020, we have tagged 1,031 adipose-clipped and 1,033 adipose-intact fish. Tagging this fall will conclude on November 19th, when the adult fish trap at the dam closes for winter. However, not all steelhead bound for Idaho will have passed by that time. There will be some fish that pass Lower Granite Dam in the spring, not long before they will spawn. We will start tagging those fish in March when the trap reopens and wrap up the second field season in April.

How many steelhead have been reported?

One of the main purposes of this study is to estimate how many wild and hatchery steelhead are caught in the state of Idaho. Last year, by November 11, 2019, 13 of the 210 adipose-clipped and 97 of the 1,024 adipose-intact fish that had been tagged had subsequently been caught and reported by anglers. That means roughly 6% of our adipose-clipped fish and 9% of our adipose-intact fish were reported as caught. This year, we have had 76 adipose-clipped fish and 125 adipose-intact fish reported as caught. So, the percentages of tags that have been reported for this year are about 7% for adipose-clipped and 12% for adipose-intact fish. The percentages of tags reported in the two years of the study are similar for both adipose-clipped and adipose-intact fish even though this year’s steelhead run is very different from last year’s run. This is a really interesting preliminary comparison of our two study years, but it is important to remember that those percentages are not final because some tags will be encountered and not reported by anglers. More to come as we calculate those reporting rates and get final estimates at the end of the study.

Where are steelhead being caught?

Steelhead are diverse critters and they return to a wide array of locations above Lower Granite Dam to spawn in the wild or return to a hatchery. Another similarity between the two years of the study is where tags have been reported. By November 11th in both years, steelhead from our study had spread out quite a bit and were encountered all over the Snake River basin, including in the Snake, Clearwater, Grande Ronde, Imnaha, and Salmon rivers where fisheries are occurring.

Please report tags!

Steelhead anglers will continue encountering tagged steelhead throughout the winter and spring, so please examine all the steelhead you catch for a tag located near the dorsal fin. Since some tags have been on fish for a few months, they could become harder to spot. That makes it even more important to carefully check fish for a tag. We greatly appreciate the anglers that have reported tags and assisted with the study, thank you! Good luck to the steelhead anglers that will brave the cold weather this winter!

If you have a tag to report click this link: https://idfg.idaho.gov/fish/tag/add

Find more salmon/steelhead articles our Wild Salmon and Steelhead page.