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Rainbow/American Smelt
 Osmerus mordax
Status
Native to
Newfoundland and Labrador.
Habitat
Smelt are a
schooling fish, inhabiting mid-waters of lakes or inshore coastal
waters. They are sensitive to both temperature and light. In
Newfoundland the smelt exists in two forms: anadromous (spend their life
in both fresh and salt water) and landlocked.
Range
Atlantic
drainages from Lake Melville in Labrador to Pennsylvania in the U.S.,
west through to the Great Lakes.
Food
Shrimp-like crustaceans, amphipods, aquatic insect larvae
and aquatic worms. Landlocked smelt may eat both young trout and trout
eggs. Also, because of their high numbers, they may have a significant
impact on a system’s aquatic ecology.
Appearance
Olive above,
blue or pink iridescence on silver sides; usually with a silver stripe
along the sides.
Breeding Biology
In spring,
the sexually mature and ripe smelt will leave the sea or large lakes and
travel upstream to spawn. In Newfoundland this may occur when ice is
still on many of the lakes, but usually occurs in March, April or May,
depending on latitude and temperature, but 8.90C is optimal.
The precise time of spawning is quite specific to the individual stream.
Spawning may last up to three weeks, but the peak seldom lasts more than
a week.
Spawning takes place at night, with spawners returning to the
lake or ocean by day. Both sexes become shorter in length as the
spawning period progresses. Two males will align themselves on either
side of a ripe female. The female releases her eggs in clusters, with
the milk of both males being released simultaneously. Eggs become
adhesive shortly after extrusion, and attach to bottom gravel.
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