Distribution

Landlocked populations also occur in lakes and ponds throughout the Atlantic region. They have been introduced in the Great Lakes and have increased their range to other Ontario drainages through unauthorized introductions.

Physical Characteristics

The rainbow smelt is a small slender fish that grows to about 25 cm (10 in). It has the following characteristics:

• olive-green on the back, becoming lighter on the sides;

• sides have a purple, pink and blue iridescence, especially when freshly caught;

• the belly is silvery;

• relatively large mouth with fang-like teeth and a protruding lower jaw;

• the caudal (or tail) fin is deeply forked;

• an adipose fin (small fatty fin ahead of the tail and on the top) is present;

• the lateral line is incomplete;

• spawning males are covered on the head, body and fins with tiny bumps (nuptial tubercles);

• smelt in freshwater are darker, becoming almost black on the back.

Smelt are fished commercially and for sport.

Winter fishing for smelt is a popular sport. Anglers take them on lines through the ice, using worms as bait. In spring, anglers dipnet or seine them in the spawning tributaries.

Commercial fishermen catch them in box nets, bag nets, gillnets, or by trawling.

The largest Maritime fishery occurs in the Miramichi estuary. Smelt are sold fresh or frozen, and are very tasty.

Natural History

The rainbow smelt is a schooling fish which is anadromous (growing and maturing in shallow coastal waters and migrating up freshwater streams to spawn). Smelt move into estuaries in the fall and to streams after the spring thaw.

Spawning occurs from February to June, usually at water temperatures from 4 to 10øC. Smelt do not necessarily return to the stream of their birth to spawn, especially if there are other nearby streams. Smelt in landlocked lakes swim up tributary streams or in some cases spawn along the shoreline. Spawning occurs at night in fast moving water. Several males spawn with one female. The fertilized eggs become sticky and attach to the bottom, sometimes forming a thick layer. One female can produce as many as 93,000 eggs. After spawning the adults return to the estuary during the day but may return upstream to spawn again on subsequent nights. Some fish die after spawning. Those that survive leave freshwater after spawning to spend the summer in coastal waters. Land-locked smelt populations remain in freshwater lakes.

Smelt eggs are I mm in diameter and take 11 to 29 days to hatch, depending on the temperature. Smelt fry are 5 to 6 mm long when they hatch, and drift downstream to brackish water.

They use water depth for cover and feed near the surface at night. Young smelt feed on plankton (tiny organisms suspended in the water) and may grow to 5 cm (2 in) by August.

Older fish eat larger invertebrates and other fish. Smelt grow most rapidly in their first year and can tolerate increasing amounts of saltwater as they get older. They prefer temperatures of 6 to 14øC and stay close to shore, seeking cover in eelgrass beds or in the mud.

Smelts in the Miramichi average 13.9 cm (5.3 in) at age 2, and 20.6 cm (8.1 in) by age 5. Southern populations grow faster. Smelt in small landlocked lakes may only reach a length of 10.2 cm (4 in). Smelt usually mature at age 2 in the Maritimes and can live to age 17. Females live longer and grow larger than males.

Smelt are eaten by bluefish, striped bass, salmonids, birds, and harbour seals.

Published With Funding from the Canada-Nova Scotia Cooperation Agreement on Economic Diversification, Resource Competitiveness Program.