Use of Natural Markers to Describe Snake River Spring/Summer Chinook Salmon Life History Characteristics and Environmental Correlates

Temporal variation in anadromous salmon abundance has been shown to be strongly correlated to aspects of climate variability. Indeed, Chinook salmon production has been linked to water chemistry, hydrologic, and temperature regimes, all of which are very likely to be altered during the next 50 years because of continued changes in the Earth’s physical climate system. However, due to the complex life history of Chinook, which includes a wide range of biological traits and behaviors among and within populations, predicting the ecological response of the species to shifting environmental conditions can be intrinsically difficult. A further complication, it is neither feasible nor practicable to use standard sampling techniques for reconstructing life history and characteristics of populations that migrate long distances to marine feeding areas thousands of kilometers away, especially those that spawn and rear in remote wilderness stream ecosystems. Utilizing advanced analytical methods, identifying and quantifying natural markers in biological tissues offers great potential as a descriptor of life history diversity, population connectivity, and environmental factors that drive recruitment processes in Snake River Spring/Summer Chinook salmon. A better understanding of the complex interactions between these populations and their environments is essential for accurately estimating juvenile carrying capacity and smolt production, forecasting future spawning run sizes, and designating critical habitat.