During 1959‐61, 10,000 catchable‐sized, hatchery‐reared, rainbow trout were jaw‐tagged and released in the upper Salmon River, Idaho, and 2,247, 619, and 539 wild cutthroat trout, Dolly Varden, and rainbow trout, respectively, were caught on hook and line, tagged, and released in the Middle Fork of the Salmon River. More than 1,500 of the tagged, hatchery‐reared, rainbow trout were recovered after being in the stream up to 1 year. Of those recovered the same season as released, more than 90 percent were taken within 2 miles of the release site. Ninety percent of those recovered after having been in the river over winter were taken within 5 miles of the release site. Of 253 tagged wild cutthroat trout recovered, 64 were recovered in release areas, and 189 were recaptured one or more miles from their release sites (average for the latter, about 19 miles). Of 95 tagged wild Dolly Varden recovered, 27 were recovered in the release areas, and 68 were recovered one or more miles from release sites (average for the latter, 22.2 miles). Twenty‐seven tagged wild rainbow or steelhead trout were recovered; 14 in release areas, and 13 downstream from the release sites. Only 25.3 percent of the cutthroat trout and 28.4 percent of the Dolly Varden were recovered within 1 mile of release sites.

Westslope Cutthroat Trout Oncorhynchus clarkii lewisi (WCT), the dominant nonanadromous salmonid in central and northern Idaho, historically were extremely abundant and widely distributed. Despite restricted harvest methods and limits since 1899, many WCT populations declined and by the 1960s, populations in several major drainages were on the brink of collapse. In response, fisheries biologists began investigating WCT population dynamics, life histories, and habitat requirements and developed evidence‐based regulations and habitat restoration alternatives. Here we describe fluvial WCT case histories that illustrate how research and management collaborated to rebuild populations. The sustained and successful effort to restore fluvial WCT in Idaho offers insights to assist WCT recovery efforts elsewhere. Today, populations in many watersheds have been rehabilitated and WCT currently inhabit about 80% of their historical stream range. Despite continued threats, many Idaho WCT populations are relatively secure, provide unique recreational opportunities, and remain an important ecological, cultural, and economic resource.