[5] As an adult it is a marine species found in the northern West Atlantic Ocean, moving into estuaries before swimming upstream to breed in freshwater habitats, but some populations live entirely in fresh water.

[7] Its common name is said to come from comparison with a corpulent female tavernkeeper ("ale-wife"),[10] or, alternatively, from the word aloofe,[11][12] possibly of Native American origin,[13] that was used to describe this fish in the seventeenth and eighteenth centuries.

The landlocked form is also called a sawbelly or mooneye (although this latter name is more commonly applied to Hiodon spp.)

Adult alewife are caught during their spring spawning migration upstream by being scooped out of shallow, constricted areas using large dip nets.

[citation needed] In spite of such biological control methods, alewife remain implicated in the decline of many native Great Lakes species.

Several threats have most likely contributed to their decline, including loss of habitat due to decreased access to spawning areas from the construction of dams and other impediments to migration, habitat degradation, fishing, and increased predation due to recovering striped bass populations.

In response to the declining population trend for alewives, the states of Massachusetts, Rhode Island, Connecticut, Virginia, and North Carolina have instituted moratoria on taking and possession.

In eastern Massachusetts, Alewife Brook flows through Arlington, Cambridge, and Somerville to the Mystic River.

An extensive habitat restoration and education project, combined with a fish ladder with monitoring cameras, is yielding increasing numbers of alewife back in the improving Mystic River watershed.