The eggs are laid on the beach and adhere to sand and gravel and hatch in about two weeks. Females lay 7,000-31,000 eggs depending on body size. Eggs hatch in 20-40 days. Food and Growth Smelt are voracious feeders on zooplankton such as copepods, amphipods, euphausiids, mysids, and other planktonic crustaceans. All species are important prey for many marine fishes, birds, and mammals.
Most species are sexually mature at age two or three years and have a maximum age of three years.
Eulachon can live to five years. Surf smelt are the largest species reaching lengths of 12 inches. Whitebait smelt and eulachon will reach lengths of nine inches and night and longfin smelt will reach lengths of six inches. Migration Eulachon and longfin smelt are anadromous-returning to fresh water areas to spawn. Mature adults then move to freshwater areas in winter to spawn.