Every May and June, adult alewives use their sense of smell to migrate from the ocean, swimming upstream into rivers, lakes, and ponds. Spawning then occurs in ponds or lakes or quiet backwaters of rivers and streams.
Data from Maine points to good water quality on lakes with healthy alewife populations. In the estuaries and the ocean, striped bass, cod, and haddock feed on alewives, and the recovery of these economically valuable fish depends, in part, on restored populations of alewives.
Alewives tie together our ocean, rivers, and lakes, playing a central part in the web of life. When they migrate back downstream, on their way to the ocean..they become food for striped bass, bluefish, weakfish, tunas, cod, haddock, halibut, American eel, rainbow trout, brown trout, landlocked salmon, small and largemouth bass, pickerel, pike, white and yellow perch, seabirds, bald eagle, osprey, great blue herons, gulls, terns, cormorants, seals, whales, otter, mink, fox, raccoon, skunk, weasel, fisher, and turtles.