Date of Award
Master of Natural Resources (MNR)
Between the 1970s and late 1990s, Summer Chum salmon abundance in the Hood Canal basin declined significantly to the point the population was listed as “threatened” under the Endangered Species Act (1999), with multiple subpopulations extirpated. The Hood Canal Salmon Enhancement Group, in partnership with the Washington Department of Fish and Wildlife, developed and implemented a supplementation program to increase spawner abundance in the Union River so that supplementation could eventually take place in the Tahuya River, where Summer Chum had been extirpated. The program, which is only possible with intense volunteer efforts, reduced extinction risks for the Union River population while returning Summer Chum once again to the Tahuya River. Using von Bertalanffy growth models, contingency tables, and a linear regression model, this paper examines differences between supplemented and non-supplemented origin Summer Chum in terms of fork lengths, age class, and return timing. Results do not indicate significant differences in growth rates among populations, though populations demonstrate minor differences in age structure. Overall run timing results for the Union River population show no real change over the supplementation period. This paper also includes results from a survey of volunteers and their motivations for involvement in the effort, which include job training and giving back to the community and its natural resources. The economic benefits of a community-driven salmon recovery effort are also discussed. The Union/Tahuya River Supplementation Program can serve as a model to recover other salmonid populations while creating strong community buy-in and reducing operating costs.
Elsen, Seth M., "Supplementation and Community Involvement as Drivers of Salmon Recovery: Summer Chum Salmon (Oncorhynchus keta) Populations in Union and Tahuya Rivers, Washington, United States" (2018). All Graduate Plan B and other Reports. 1202.
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