Tracking Fish and Human Response to Earthquakes on the Northwest Coast of Washington State,USA: A Preliminary Study at Tse-whit-zen

Evidence of large earthquakes occurring along the Pacific Northwest Coast is reflected in coastal stratigraphy from Oregon to British Columbia, where there also exists an extensive archaeological record of Native American occupation. Tse-whit-zen, a large Native American village dating between ～2800 yrs BP and the historic era, located on the Olympic Peninsula of Washington State, was excavated with exceptionally fine stratigraphic control allowing for precise comparison of these natural and cultural records. Here we report on the ～10,000 fish remains from one 2 × 2 m excavation block; this assemblage spans the timing of one seismic event, allowing study of changes in relative taxonomic abundance through time that may coincide with earthquakes or other environmental changes. Results indicate a wide variety of fish taxa were used throughout the dated occupation. Comparisons of fish use before and after one earthquake event shows a decline in salmon (Oncorhynchus sp.) and an increase in herring (Clupea pallasii), shifts consistent with earthquake-related habitat loss. This serves as a pilot study for a large-scale collaborative project that is drawing on the range in animal types (invertebrates, mammals, birds, and fishes) to assess human response to gradual and abrupt environmental change at Tse-whit-zen.