Lessons Learned from More than One-Hundred Years of Golden Trout Management and Recovery in California
Molly R. Stephens, Stanley J. Stephens, and Charles C. Krueger
Abstract.—Native golden trout of California’s upper Kern River basin have inspired anglers and scientists alike with their beauty, ecology, and evolutionary history. Three Rainbow Trout Oncorhynchus mykiss subspecies comprise the golden trout complex: California Golden Trout O. m. aguabonita, Little Kern Golden Trout O. m. whitei, and Kern River Rainbow Trout O. m. gilberti. This chapter focuses on restoration and management of the first two subspecies, California Golden Trout and Little Kern Golden Trout. Agency biologists, other scientists, and citizens have all worked for more than 100 years to protect and save these subspecies from a range of threats, some of fishery managers’ own making and some threats evolving over time. Major problems have included overharvest by anglers, overgrazing of habitat by livestock, competition and predation by nonnative Brown Trout Salmo trutta and Brook Trout Salvelinus fontinalis, and hybridization with introduced nonnative forms of Rainbow Trout subspecies; these factors drove both species perilously close to extinction by the late 1960s. Little Kern Golden Trout were listed as threatened in 1978 under the U.S. Federal Endangered Species Act. That same year, the federal government designated large portions of California Golden Trout and Little Kern Golden Trout native watersheds as the Golden Trout Wilderness. Management actions to prevent extinction and conserve these subspecies have included angling regulations, livestock grazing restrictions, barrier construction, chemical treatments to remove nonnative trout, and research to identify and quantify genetic introgression of nonnative Rainbow Trout genes into native golden trout populations. Restoration efforts have, thus far, averted extinction, allowed populations to rebound, and provided several important lessons on genetic management of closely related subspecies, including pitfalls of a zero-introgression target for conservation, the potential need to continue management indefinitely, being responsive to emerging threats, recognizing that barriers to upstream fish movement can be useful, the caveats of using hatcheries for conservation, the potential role of native trout donor populations to facilitate restoration, and the need to harness public and stakeholder understanding and support for species conservation.