Steelhead: A-run or B-run?

Is This Idaho Steelhead A-Run or B-Run?

Steelhead A-run or B-run – can you tell? Idaho’s steelhead are classified into two groups, A-run and B-run, based on their size and ocean life history.

Steelhead are actually rainbow trout that are anadromous fish, meaning they migrate to the ocean and return to fresh water similar to a salmon. Idaho’s A-run steelhead are most commonly found in the Snake and Salmon rivers. Their return from the ocean usually starts between June and August and most often they return after spending one year in the ocean. Due to their early return and length of stay in the ocean, they weigh 4 to 9 pounds and are generally 23 to 28 inches long. Salmon River steelhead average 7 pounds and 27 inches.

The B-run steelhead are more commonly found in the Clearwater River, but some return to tributaries in the Salmon River. These fish usually spend two years in the ocean, and begin their migration to their spawning grounds later in the summer or fall of the year – usually late August or September. Due to the extra year and summer of growing in the ocean, they return as much bigger fish.

B-run steelhead average between 10 and 13 pounds and are 31 to 34 inches long. A steelhead can grow very large if it spends a third year in the ocean before it returns to Idaho to spawn. These steelhead are on average larger than 37 inches and can weigh more than 20 pounds. The Idaho state record steelhead weighed 30 pounds and was caught in 1973 in the Clearwater River.

Steelhead Fishing on the Salmon River
Contact Silver Cloud for steelhead fishing information

Steelhead: A-run or B-run? was last modified: January 3rd, 2020 by Sean Bierle