Watching Steller Sea Lions feed on eulachon as part of an environmental eDNA study funded by the National Geographic Society. We are testing the efficacy of environmental DNA to provide an index of abundance for eulachon (Thaleichthys pacificus). Eulachon are a small anadromous smelt with extremely high fat content of any forage fish (20% fat leading to the name “candlefish”). They are the first anadromous fish after the long winter, and are a culturally significant staple food source to Northwest Coast native people including the Chilkat and Chilkoot peoples of the Tlingit nation. Eulachon are consumed fresh, dried, or smoked, and are frequently rendered into oil. The oil was historically the most important trade item on a network of ‘grease trails’ between coastal and interior peoples, and it is still used and traded extensively.
The pulse of millions of eulachon at the end of the winter famine period also represents an important seasonal prey resource for terrestrial and marine predators including enormous congregations of seabirds, bald eagles, seals, sea lions, harbor seals and humpback whales, some of which are listed under the ESA.a biologically and socially important fish.
The primary objectives of this research are to (1) develop an affordable DNA-based method to provide an annual index of abundance of eulachon, and (2) to test DNA-based methods as a tool to monitor Steller sea lion and humpback whale relative abundances feeding at pre-spawning eulachon congregations.
