Spirinchus thaleichthys (Ayres, 1860)
Longfin smelt
photo by Bull. U.S. Bur. Fish.

Family:  Osmeridae (Smelts)
Max. size:  20 cm TL (male/unsexed); max. reported age: 3 years
Environment:  benthopelagic; freshwater; brackish; marine; depth range - 137 m, anadromous
Distribution:  North Pacific: Prince William Sound, Alaska to Monterey Bay, California, USA. Landlocked in Washington and Union Lakes in Washington, USA.
Diagnosis:  Dorsal spines (total): 0-0; Dorsal soft rays (total): 8-10; Anal spines: 0-0; Anal soft rays: 15-19; Vertebrae: 55-61. Distinguished by its long upper jaw, which reaches at least below the middle of the eye in adults; the fine teeth in a single row on the vomer and palatine bones; and the 38 to 47 gill rakers on the 1st arch (Ref. 27547). Gill rakers long; lateral line incomplete and reaching not quite to below dorsal fin (Ref. 27547). Breeding males have tubercles on upper sides of paired fins (Ref. 27547). Pale olive brown dorsally, silvery white on sides and ventral surfaces; fins usually stripped along the rays, but inter-ray membranes clear;. Young are translucent with 2 rows of large black spots, on each side of the midline of the back, from head to caudal peduncle; peritoneum silver with light speckling. Spawning males with moss-green backs, and dense, black speckling on the head and dorsal surface of the body. The peritoneum is silvery with black speckling.
Biology:  Found close to shore, in bays and estuaries and ascends coastal streams to spawn (Ref. 5723). There are landlocked populations (Ref. 5723) but these do not reach as great a size as sea-run fish (Ref. 27547). Anadromous (Ref. 96339). Individuals found in brackish and salt water feed on small crustaceans (Ref. 1998). Fish from the sea are reported to have good flavor, but supply is limited (Ref. 6885). Often abundant during the spawning run, but flesh reported to be soft and oily, easily spoiling (Ref. 1998).
IUCN Red List Status: Least Concern (LC); Date assessed: 01 March 2012 Ref. (130435)
Threat to humans:  harmless


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