Diamond Lake

Diamond Lake in southern Oregon is one of the most remarkable conservation comeback stories in American freshwater fishery management — a 3,015-acre mountain lake that was completely poisoned in 2006 to eliminate an invasive tui chub population that had devastated the rainbow trout fishery, then restocked with pure-strain rainbow trout that have grown into one of the finest trophy stillwater fisheries in the Pacific Northwest. Before the chub invasion, Diamond Lake was famous throughout Oregon for its exceptional rainbow trout — a legend among Oregon fly fishers. The chubs, which were illegally introduced decades ago, reproduced explosively and crowded out the trout, crashing the fishery by the early 2000s. ODFW's decisive action — treating the entire lake with rotenone in 2006 and restocking with certified chub-free rainbow — restored the fishery to a quality that exceeds even its historical reputation. The restored Diamond Lake rainbows average 2–4 pounds with exceptional fish over 8 pounds caught each season. The lake's shallow, weedy character creates perfect Callibaetis mayfly and chironomid habitat, and the fish have responded with exceptional growth rates on this abundant food supply. The Mount Thielsen backdrop — one of Oregon's most dramatic volcanic peaks — makes every visit a scenic as well as fishing experience. The lake is now managed as a trophy stillwater with special regulations including size limits and gear restrictions in designated sections. The ODFW's success at Diamond Lake has become a model for invasive species removal and native fishery restoration that has been replicated elsewhere in the Pacific Northwest.