The eulachon (Thaleichtys pacificus (Girad)), is one of five species of smelt (Family: Osmeridae) found in Alaska. The name, eulachon, is derived from the Chinook language of the Pacific Northwest native peoples and has several variations of which hooligan is the most commonly used in Alaska. The eulachon is also known as the candlefish because of its traditional use as a candle when dried and fitted with a wick. The genus name, Thaleichtys, is Greek for rich fish, a description which lends to the eulachon's reputation as having flesh of a high oil content.

General description: The eulachon is a small fish up to 10 inches in total length. It is generally distinguished from other Alaska smelts by having the front of the dorsal fin begin well behind where the pelvic fin is attached to the body and by having circular grooves on the gill covers. The mouth is equipped with moderately developed canine-like teeth which are lost as the fish approaches maturity, so by spawning time it usually has no teeth at all. Eulachon are generally blue-silver in color turning to gray-brown at spawning time when the males are easily distinguished from the females by tubercles on the head and on the scales along the lateral line, more musculature development along the lateral line, and longer paired pectoral and pelvic fins.

Life history: Eulachon are anadromous. They spawn and hatch in fresh water and grow to maturity in the sea where as juveniles and adults they feed mainly on euphasids, a small shrimp-like crustacean sometimes called krill.

As the spawning season approaches, eulachon gather in large schools off the mouths of their spawning streams and rivers. The upstream migration is closely keyed to the water temperature of the stream. In Southeast Alaska, the migration can occur as early as April; while in central and western Alaska, it generally takes place in May. Some streams have two separate but overlapping migrations. Males usually outnumber the females during the spawning migration.

Eulachon generally spawn in the lower reaches of the river or stream. Eggs are "broadcast" over sandy gravel bottoms where they attach to sand particles. The eggs hatch in 21 to 40 days, depending on the water temperature. Newly hatched young are carried to the sea with the current where they feed mainly on copepod larvae and other plankton. After three to four years at sea, they return as adults to spawn. After spawning, the majority of eulachon die.

Distribution: In Alaska eulachon are seasonally abundant in most major drainages from Southeast west to Cook Inlet and become less abundant westward out to the Aleutian Islands and to the Pribilof Islands in the Bering Sea. Some drainages with eulachon migrations include the Unik (Eulachon), Stikine, Taku, Mendenhall, and Chilkat rivers in Southeast; the Situk near Yakutat,; the Copper River Delta area near Cordova; and the Kenai, Susitna, and 20-Mile rivers in Cook Inlet. Eulachon are also present in many smaller streams with varying abundance. In the westward margins of their range, eulachon are displaced by a similar appearing smelt, the rainbow smelt (Osmerus mordax (Mitchill)).

Fishery: The eulachon has long had an important role in the economy of the Pacific Northwest, British Columbia, and Alaska Native populations. Until the early 1900s, large numbers of natives gathered on rivers with major migrations of eulachon to dry them and extract the oil from their flesh with simple presses. The eulachon was important as a food staple and as barter with inland tribes, thus the famous "kleena" or grease trails of Southeast Alaska and British Columbia.

In modern times in Alaska, the eulachon is important as a personal use and subsistence species. Eulachon are taken with dipnets, gillnets, and seines. They are frozen, dried, and smoked mostly for human consumption.

Ecology: Eulachon are important in the food chain as a prey species. Newly hatched and juvenile eulachon are food for a variety of larger marine fish such as salmon. Marine mammals including seals, sea lions, and beluga whales also feed on them in abundance when the eulachon gather off the mouths of their spawning streams. Spawning eulachon and spent bodies of spawned-out eulachon are eaten by gulls, eagles, and bears and by the white and green sturgeon in the larger rivers of Southeast Alaska, British, Columbia, and the Pacific Northwest. The spent bodies of spawned-out eulachon also contribute to the nutrient cycle as they decompose.

Text: Larry Bartlett
Illustration: Ashley Dean
Revised and reprinted 1994