Illustration by Joseph R. Tomelleri ©
Osmerus mordax - scientific name
(Non-Native Fish) The rainbow smelt is a small slender member of the Osmeridae family. Similar to trout and salmon, rainbow smelt have a dorsal fin and an adipose fin on the dorsum. Additional characteristics include teeth, as well as a long thin body with purple, pink and blue iridescent sides.
During their spawning period in April, people typically use dip-nets to capture (e.g., term; "smelt-dipping) them from streams. The rest of the year, rainbow smelt school in lakes adjacent to cool, dark waters.
Smelt populations in the Great Lakes are no longer as large as they once were and smelt dipping has suffered accordingly. The best smelt dipping these days is in Upper Peninsula streams.
But an unusual hook-and-line fishery has developed during the winter. Using lights at night to draw smelt up from the bottom, anglers using tiny hooks tipped with insect larvae (primarily spikes and wax worms) catch smelt in a handful of inland lakes and some Great Lakes bays. The best-known hook-and-line smelt fisheries are Crystal, Higgins and Green Lake (Grand Traverse County) as well as in Keweenaw Bay near Baraga. But other lakes with good smelt populations include Lake Charlevoix, Gratiot Lake (Keweenaw County), and Dodge and Island Lakes in Schoolcraft County.
Their diet includes aquatic invertebrates and other fish, including small rainbow smelt, sculpins, burbot and whitefish. In the Great Lakes, shrimp-like crustaceans are also a principal food items for rainbow smelt.
Similar to many migratory species, rainbow smelt ascend tributary streams to spawn over gravel. Their spawning period begins in the early spring (April), and extends for about a three-week period. Cool weather conditions may delay and/or extend the spawning period. Rainbow smelt spawn at night and usually return to the lake by morning. Rainbow smelt fry grow rapidly; in the Great Lakes most are mature by the end of two growing seasons, and nearly all will mature by the end of the third season. As with many other fish species, females grow faster and larger and live longer than males. Rainbow smelt grow to an average size of 3 to 6inches in length in the Great Lakes.
The rainbow smelt is native to North America's Atlantic coast from New Jersey to Labrador, and also occur naturally as landlocked populations in some lakes of New England and eastern Canada. In 1912, rainbow smelt were stocked in Crystal Lake, Michigan, and from there they made their way to Lake Michigan. Since rainbow smelt are sensitive to temperature and light, they keep to the mid-waters of the lake, and may descend to near bottom during bright daylight. A cool 45 degree F is their optimum water temperature.
Department of Natural Resources