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Diversity of Pacific Trout

Distribution map of Cutthroat Trout subspecies.

Excerpt of distribution map of Cutthroat Trout subspecies (Oncorhynchus clarkii ssp.) in western North America from Penaluna et al. 2016, Fisheries

Pacific trout of the genus Oncorhynchus are greatly
valued for ecological, socioeconomic, and cultural reasons,
and have been the subject of substantial research and
conservation efforts. Although Pacific trout share many
notable life-history traits with Pacific salmon and salmonids
in general, they are also distinctive in that they are optionally
anadromous (at least for some forms of O. mykiss and O.
clarkii
), iteroparous (repeat spawners), spring spawners
(varies with local conditions and the months of spawning can
vary widely), and they can live up to 10 years or more.


Research Description:


Pacific trout are found in western North America in catchments that drain into the Pacific Ocean, but some populations exist in closed basins, whereas others occupy streams that drain into the Gulf of Mexico east of the Continental Divide. However, substantial declines in abundance and contractions in distribution across species and subspecies, by at least two thirds from historical levels, have led to elevated protection in some or whole portions of their range. Further, two Cutthroat Trout subspecies, the Alvord Cutthroat Trout O. clarkii alvordensis and the Yellowfin Cutthroat Trout O. clarkii macdonaldi, are considered extinct.

Key Findings:


Human influences leading to declines in Pacific trout began with Euro-American colonization of North America (Penaluna et al. 2016). The decline of Pacific trout over recent decades and, in some cases, the last century reflects the challenges of balancing societal values with natural resources and wild places under a changing climate. Legacies of past and continuing overfishing and land-use activities on their habitats have led to habitat degradation from forest harvest, agriculture, cattle grazing, mining, migration barriers, non-native species, and climate change.
Map of western North America showing current and historic ranges of Pacific trout species and O. mykiss subspecies.

Pacific Trout species, Oncorhynchus species and Oncorhynchus mykiss subspecies, of western North America. From Penaluna et al. 2016.

Management Implications:


Pacific trout have evolved characteristics including genetic, phenotypic, and life-history diversity and their ability to migrate long distances across diverse habitats, which will be the keys to their future persistence. Ultimately, it will be important to continue to strengthen the relationships among science, management, and the public, to increase flexibility in management, restore the diversity of Pacific trout, and consider social pressures that magnify their vulnerability.See link to Science Stories feature :" Native Pacific Trout: Swimming into the Future?"
Map of western North America showing current and historic ranges of Cutthroat Trout subspecies.

Cutthroat Trout Oncorhynchus clarkii subspecies of western North America. From Penaluna et al. 2016.

Selected Publications:


Arismendi, I., B.E. Penaluna, D. Gomez-Uchida, Cecilia Di Prinzio, D. Rodriguez-Olarte, F.M. Carvajal-Vallejos, J.I. Mojica, R. Mazzoni, V. Cussac, M. Maldonado, E. Pellegrini Caramaschi, A.J. Zeballos, A. Villalba, P.A. Van Damme, L. Cordova, R. Iglesias-Rios, D. Canas-Rojas, M. Canas-Merino, J.N. Benavente, M. Nunez-Flores, S.S. Musleh, and P. Savaria. 2019. Trout and Char of South America. Chapter 9 in: Kershner, J.L., J.E. Williams, R.E. Gresswell, and J. Lobon-Cervia (eds.), Trout and Char of the World. American Fisheries Society, Bethesda, MD. 777 p. doi: https://doi.org/10.47886/9781934874547

Budy, P., K.B. Rogers, Y. Kanno, B.E. Penaluna, N.P. Hitt, G. P. Thiede, J. Dunham, C. Mellison, W.L. Somer, and J. DeRoito. 2019. Distribution and status of trout and Char in North America. Chapter 7 In: Kershner, J.L., J.E. Williams, R.E. Gresswell, and J. Lobon-Cervia (eds.), Trout and Char of the World. American Fisheries Society, Bethesda, MD. 777 p. doi: https://doi.org/10.47886/9781934874547

Shepard, B., I. Arismendi, B. David, A. Caudron, M. Dedual, M. Draper, Z. Hogan, D. Impson, B.E. Penaluna, D. Vermillion, and K.A. Young. 2019. Global perspectives on the Management of Trout and Char. Chapter 15 In: Kershner, J.L., J.E. Williams, R.E. Gresswell, and J. Lobon-Cervia (eds.), Trout and Char of the World. American Fisheries Society, Bethesda, MD. 777 p. doi: https://doi.org/10.47886/9781934874547

Whitely, A., B.E. Penaluna, E.B. Taylor, S. Weiss, A. Abadia-Cardoso, D. Gomez-Uchida, Itsuro Koizumi, and P. Trotter. 2019. Trout and Char: Genetics, Taxonomy, and Systematics. Chapter 5 in: Kershner, J.L., J.E. Williams, R.E. Gresswell, and J. Lobon-Cervia (eds.), Trout and Char of the World. American Fisheries Society, Bethesda, MD. 777 p. doi: https://doi.org/10.47886/9781934874547

Penaluna, B.E., A. Abadia-Cardoso, J.B. Dunham, F.J. Garcia de Leon, R.E. Gresswell, A. Ruiz-Luna, E.B. Taylor, B.B. Shepard, R. Al-chokhachy, C.C. Muhlfeld, K.R. Bestgen, K. Rogers, M.A. Escalante, E.R. Keeley, G. Temple, J.E. Williams, K. Matthews, R. Pierce, R.L. Mayden, R.P. Kovach, J.C. Garza, and K.D. Fausch. 2016. Conservation of native Pacific trout diversity in western North America. Fisheries 41(6):286–300. http://dx.doi.org/10.1080/03632415.2016.1175888