The eulachon grease trade was particularly important.

Eulachon — small, intensely fatty fish that appear in coastal rivers for brief but abundant spring runs — were rendered into a highly preserved, calorie-dense oil that was one of the most sought-after trade commodities in the pre-contact Northwest.

The routes along which eulachon grease was traded inland from the coast were so important that they came to be called “grease trails” — a term that persists in the historical and archaeological literature.

The Tatshenshini-Alsek region, with its passes connecting the coast to the interior, was part of this trading geography.