Inventory of Salmon, Steelhead Trout, and Bull Trout: South Fork Salmon River, Idaho

摘要

Aquatic habitats and respective fish populations were studied in the South Fork Salmon River during the summer of 1977. From the Warm Lake Bridge to the headwaters the channel consisted of 74 percent riffle and 26 percent pool, with surface substrate of 21 percent boulder, 40 percent rubble, 24 percent gravel, and 15 percent fine sediment. Below the Warm Lake Bridge to the confluence of the Secesh River the channel consisted of 55 percent riffle and 45 percent pool, with surface substrate of 32 percent boulder, 35 percent rubble 16 percent gravel, and 17 percent fine sediment. Juvenile chinook salmon and rainbow-steelhead trout were found throughout the river, except in the upper 5 miles (8km), where only bull trout were found. Of the habitat attributes measured, only stream width showed any correlation with fish populations. As stream width increased in the river reached above the Warm Lake Bridge, bull trout numbers decreased.