pdf version - South Dakota Department of Game, Fish and Parks

SMELT (family Osmeridae)
Rainbow Smelt
Osmerus mordax
Quick key characteristics: The rainbow smelt is found in cold-water
habitats. It has relatively large scales, soft fi ns with a somewhat elongate
anal fi n, and an adipose fi n. It has a forward-facing mouth, a pointed, blunt
snout, and although its body is taller than wide, it is relatively slender.
Similar species in South Dakota: lake whitefi sh, cisco (lake herring), trout
and salmon
Identifi cation: The combination of (1) silvery coloration (sometimes with
dark lateral stripe), (2) large teeth on jaw, tongue, and roof of the mouth, (3)
protruding lower jaw, and (4) large mouth with upper jaw bone (maxillary)
extending backward at least to a point below the pupil separates this species
from others in South Dakota.
Range: The rainbow smelt is native to the Arctic, northern Atlantic and
northern Pacifi c oceans, and also inhabits streams fl owing into them. It was
introduced into Lake Sakakawea, North Dakota, on the Missouri River as
prey for cold-water sport fi shes. It has since spread downstream into Lake
Oahe, South Dakota and beyond.
Items of interest:
• Prey for many species including northern pike, Chinook salmon, lake
trout, and walleye
• Feeds on crustaceans, insects, and
small fi shes
• May form large schools and
undertake spawning migrations
• May reach 14 in
41