Smelt

Smelt is a common name for several small, silvery fish in the family Osmeridae. They are typically elongated and reach roughly 6 to 20 centimeters in length. Smelts inhabit cool temperate waters of the Northern Hemisphere, and most species migrate between saltwater and freshwater to spawn, while a few populations reside entirely in freshwater.

The term covers multiple genera, including Osmerus and Hypomesus. Notable species include the rainbow smelt (Osmerus mordax), the European smelt (Osmerus eperlanus), surf smelt (Hypomesus pretiosus), and delta smelt (Hypomesus transpacificus), the latter being endangered in parts of its native range in the Sacramento–San Joaquin Delta.

Biology and ecology: Smelts primarily feed on zooplankton and small crustaceans. Spawning usually occurs in spring and takes place in shallow rivers, estuaries, or gravel beds. Eggs are laid in these environments and hatch after several days to weeks, depending on water temperature. Juveniles feed on plankton and small invertebrates as they grow and migrate to feeding grounds.

Human use and conservation: In some regions, smelt are commercially fished for human consumption; they are often salted, dried, smoked, or canned, and may also be used as bait. Several populations are monitored for conservation, with notable concerns for delta smelt due to habitat alteration and water management, which have led to protective and management measures in certain areas.

Note: The term smelt also refers to the process of smelting metal, which is unrelated to the fish.