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Idaho Fish and Game

Steelhead Surge Into Idaho Rivers

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Steelhead zoomed over the last major dam on the Snake River as river temperatures cooled enough to bring stalled fish home to Idaho. Steelhead on their way back to Idaho often waste no time clearing some of the dams on the Columbia River but do not enter the lower Snake River in Washington because water temperatures are too warm for them. Once the temperature cools to their liking, the fish bolt for home, crossing the four lower Snake dams quickly. These fish return from the ocean to spawn next spring in tributaries of the Snake River. Since mid-September, about 84,000 fish have cleared Lower Granite Dam, the last dam on the lower Snake. That represents about 81 percent of the total run of 103,367 steelhead that have crossed the dam in the last three weeks. At the same time, the counts at Bonneville Dam on the other end of the river complex are nearing an end. Idaho Fish and Game biologists expect a total run of about 141,000 fish which is 40 percent higher than the 10-year average but substantially lower than the last two years the state's anglers have enjoyed. The 2002 count was 222,000 while the long-term average is 101,000. The runs of the last three years are the only ones in the past decade to exceed 100,000 steelhead. Biologists are seeing the hatchery B-run of steelhead coming back at only about half the preseason forecast. The B-run fish, mostly headed for the Clearwater River, are the largest Idaho steelhead and inspire a great deal of enthusiasm among anglers. The factors that have caused a drop in forecast from 26,000 to about 13,000 of these hatchery steelhead are largely unknown. Fish biologists have not agreed on a single cause for the decline from the early forecast.