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Eulachon, Thaleichthys pacificus
		Appearance and Identification: · Largest of North American smelt, 20-30 cm TL · Elongated body, laterally compressed: depth 15-20% of TL · Large mouth: maxilla reaches middle to past rear margin of eye, small pointed teeth · Pectoral fins reach ⅔ of way to pelvic fins, gill covers with concentric striations · Brown to dark blue back and head, silver to white underside, unmarked fins · Spawning Adults: may lack pointed teeth on jaw o Males: mid-lateral ridge present, breeding tubercles on head, body, fins o Females: may have undeveloped breeding tubercles, oily flesh · Fin rays: dorsal 10-13, pelvic 8, pectoral 10-12, anal 18-23 · Lateral line scales: 70-78 (complete)
Life History:
		Eulachon are anadromous and spend the majority of their lives in the ocean and return back to coastal freshwater streams to spawn and die. Most eulachon live 3 years though some fish are actually repeat spawners and live to age 5. When eulachon first hatch, the larvae are washed downstream towards the sea, and they don’t become free swimming juveniles until they have reached a total length of 50-80 mm. In the ocean eulachon live and feed in both shallow and deep water areas, focusing their diet on copepods, euphausid shrimp, and other crustaceans. Most eulachon reach sexual maturity after 3 years and enter their natal streams between December and May. In California spawning starts in mid-March and lasts through May in the northern part of the state. Spawning migration occurs in a narrow window of 4-8°C, and may slow or stop if the water temperature rises above or falls below the favorable range. Eulachon rarely swim further than 10-12 km upstream, and males are typically first to arrive at the spawning grounds typified by gravel, sand, wood, and other debris. Actual breeding occurs on a large scale at night when many females deposit an average of 25,000 eggs each. The eggs have two membranes, the first of which ruptures on the substrate to anchor the remaining embryo to the streambed. They generally hatch in 2-3 weeks, with a greater incubation time for eggs in cold water.
Links to Other Research
	Here's a list of California watersheds where Eulachon may be found. © 2003 - Regents of the University of California Division of Agriculture and Natural Resources Communication Services E-Mail Web Master ANR Non-Discrimination Statement