Goose Lake Redband Trout

Oncorhynchus mykiss ssp.

Goose Lake is a 90,000 acre shallow, turbid, and highly variable alkaline lake on the California and Oregon border. In most years, tributary streams drain locally out of southern Oregon around the town of Lakeview and off of the west flank of the Warner Mountains into the lake as a closed basin. During extremely dry years – only 4 times since 1420, most recently in 1992 - the lake completely dries up. On the other extreme, following successive wet springs, the lake spills over its southern, historic outlet into the headwaters of the Pit River and the Sacramento River system.

Goose Lake redband trout, a unique subspecies of rainbow trout, have adapted to these conditions for thousands of years. Recent genetic research suggests that coastal rainbow trout that had occupied the connected Upper Pit and Goose Lake systems during a wetter climate were isolated from their ancestors by natural barriers on the Pit and Sacramento Rivers (Currens et al., 2009). These isolated redband trout of the Upper Sacramento and McCloud River system are known as Oncorhynchus mykiss stonei, first recognized by Livingston Stone in 1885. Like other forms of trout found in the Great Basin, redband trout in the Goose Lake system are tolerant of warm, alkaline water and have adopted an adfluvial life history. Large adults, up to 20 inches in length, reside in the lake and feed on Goose Lake tui chubs and fairy shrimp. During the spring runoff, these adults migrate up the connected tributary streams to spawn. Some individuals also exhibit a resident life history in these streams, a strategy that has allowed the subspecies to disperse and recolonize Goose Lake following periods where it is completely dry. All redband trout persisting in headwater streams of the Upper Pit express a resident life history.

Context Map

Beginning in the 1800’s, Goose Lake was utilized as a commercial fishery to support logging camps in the basin. Increasing development followed and by the late 20th century, the water quality and connectivity effects of agriculture severely reduced the productivity of the Goose Lake system. Additionally, introduced non-native trout competed with redbands in Goose Lake tributaries and portions of the Upper Pit. In the 1990s, prolonged drought and the threat of Endangered Species Act listing of Goose Lake redbands and other endemic fish led to the formation of the Goose Lake Fishes Working Group. Initial actions included identifying and modifying diversion structures to ensure fish passage, protection of critical spawning and rearing habitats to the east of Goose Lake, and limits to non-native fish stocking in Goose Lake tributaries. Perhaps due to uncertainty regarding their relation to trout in the Goose Lake system, redbands in the Upper Pit system have received less attention. The subspecies is designated as a Sensitive and Management Indicator Species by the U.S. Forest Service, as Sensitive by Oregon Department of Fish and Wildlife, and as a State Species of Special Concern in California.

Reconnecting headwater populations to Goose Lake remains the highest conservation priority in the Goose Lake basin. Other threats include the competition, exclusion, and hybridization impacts of non-native trout introductions, particularly in California, flow alteration associated with dams and diversions, and sedimentation and channelization associated with livestock grazing and pasture irrigation. Trout Unlimted supports the continued efforts to conserve this unique and highly adaptive native trout.

Our CSI analysis incorporated data from Oregon Department of Fish and Wildlife’s Status and Distribution of Native Fishes in the Goose Lake Basin assessments from 2007 and 2008, the 2004 Upper Pit River Watershed Assessment, the 1996 Goose Lake Fishes Conservation Strategy, the 2008 SOS: California’s Native Fish Crisis report, and additional information from Claude Singleton, Bureau of Land Management; Stephanie Gunkel and Shannon Hurn, Oregon Department of Fish and Wildlife; Marty Yamagiwa, Modoc National Forest; and Stewart Reid, Western Fishes. We are grateful for these contributions to our understanding of this species. A complete list of data sources is provided separately.

Data for several CSI indicators affecting Goose Lake redband are unavailable or uncertain in California, including a clear understanding of the historic distribution, a complete picture of the artificial barriers in the system, and abundance data that would allow more robust comparisons of productivity between different streams. Quantitative estimates of introgression are unavailable in Oregon or California. These data would further refine the CSI results.

Prepared by Kurt Fesenmyer, TU, 8/11/2009

Key CSI Findings

• The current distribution of Goose Lake redband trout is nearly equivalent to its historic distribution.
• Two population groups of Goose Lake redband exist. The adfluvial and resident population in the Goose Lake basin is large and has generally higher population integrity scores than the resident population in the Upper Pit system.
• The lowest population integrity scores reflect limited population extents, decreased by agricultural diversions, dams, and natural barriers.
• Headwater streams have the highest habitat integrity scores. In the lowlands and along mainstem streams, habitat integrity scores are degraded by fragmentation and water quality impacts associated with agriculture, roads, and dams.
• Most subwatersheds have high future security scores associated with minimal threats of land conversion and resource extraction.
• Multiple climate change factors, continued competition with non-native trout species, and wind and geothermal energy development represent the greatest additional future risk to this subspecies.

Table 1. CSI scoring results for Goose Lake redband trout. All indicators are scored from 1 (poorest) to 5 (best): see framework documentation for details.

Conservation Strategies Map