Cutthroat Trout: Evolutionary Biology and Taxonomy

Where the Rubber Meets the Road: Further Research Needs and Implications for Cutthroat Trout Management

Luke Schultz, Neil F. Thompson, C. Nathan Cathcart, and Thomas H. Williams


Abstract.—The broad distribution and regional variation of Cutthroat Trout Oncorhynchus clarkii across western North America has led to considerable interest in the different forms from both scientific and recreational perspectives. This volume represents an attempt to describe this observed diversity with the most current information available and suggests a revised taxonomy for Cutthroat Trout. However, what is proposed in this volume will be subject to change or refinement as new techniques and analytical tools become available. In particular, remaining uncertainty would benefit from a comparison of all described lineages with a common set of morphological and genetic markers. A range-wide collection of voucher specimens will help to document variation in these characteristics, and we encourage field biologists to prioritize these collections. Future revisions will benefit from agreement on a species concept and explicitly state the assumptions of the chosen species concept. We encourage collaboration between managers and taxonomists to accurately delineate units of conservation that can be used by decision makers tasked with ensuring the long-term persistence of Cutthroat Trout lineages. The proposed taxonomic revisions herein validate many of the ongoing management strategies to conserve Cutthroat Trout, but we advise additional consideration of life-history diversity as an attainable management target. For long-term persistence of all Cutthroat Trout, maintaining and expanding the availability of high quality, well-connected stream and lake habitats will be a necessary first step to achieving desired conservation outcomes. Moreover, restoring and protecting ecological processes are key to conserving the diversity found within and among lineages of Cutthroat Trout. In systems where native Cutthroat Trout have been extirpated or suppressed, captive propagation and translocation are two potentially available tools to re-establish or reinvigorate populations. Last, we encourage fisheries managers and taxonomists to embrace the challenges that come with conserving locally unique forms of wide-ranging species like Cutthroat Trout.