San Francisco Estuary and Watershed Science

Since the mid-1800s the Sacramento–San Joaquin river system in the California Central Valley has experienced a dramatic decline in the distribution and abundance of wild salmon, along with many extirpations. The causes of the decline are many, and have been well studied. Despite restoration efforts spanning decades and involving large expenditures, runs of wild salmon in the Central Valley continue to decline. Using the most probable policy and ecological scenarios (i.e., effects of continued harvest, continued stocking from hatcheries, changing climate, continued human population growth and associated demands for scarce water resources) and based on expert judgment, we assessed the most likely future of wild salmon runs in the Central Valley in 2100. We posed seven open-ended questions to senior salmon science and policy experts in federal and state agencies; local, regional, and national organizations; non-governmental organizations; and universities. With a promise of complete and permanent anonymity, these experts provided answers. Most experts concluded that by 2100 wild salmon in the Central Valley will be extirpated or minimally abundant if current trends continue.