Sedimentary evidence of increasing river discharge from Namu Lake, B.C. during a period of fluctuation in the staple pink salmon fishery

Summary

Pacific salmon has been a vital resource to the people of British Columbia as far back as 9,700 years before present (BP). Sediment cores collected from Namu Lake, British Columbia provide evidence for paleoenvironmental conditions that may have led to the decline of the pink salmon population ~3400 cal years BP. Archaeological evidence obtained from the Namu shell midden reveal fluctuating pink salmon populations at this time. Particle size analysis of the lake sediment cores indicate fluctuations in river discharge as well as changes in erosional intensity. Particle size coupled with radiocarbon dating revealed low variability and high minimum grain size values during this interval. An increase in alkali earth elements; Mg, Na, and K during this time also indicate that erosional mechanisms had intensified throughout the interval 3400-2300 cal years BP, likely due to consistently wetter conditions along the coast. Increased discharge from the Namu River would have resulted in increased sediment entering Namu Lake and eventually the outflowing river; the spawning ground for the pink salmon. The results of this study help us to understand the sensitivity of salmon to fluctuating hydrological conditions and how future populations might respond to changes in climate.

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This Resource is Part of the Following Collections

• Society for American Archaeology 80th Annual Meeting, San Francisco, CA (2015)

Keywords

Spatial Coverage