About the Species
Alewife are an anadromous species (can live in both fresh and salt water). Some alewife stay in fresh water all their lives. Others migrate to the ocean and return to freshwater to spawn. Alewife populations have seen big declines throughout much of their range. They are vulnerable to many stressors and threats including blocked access to spawning grounds and habitat degradation caused by dams and culverts.
Alewife are often confused with blueback herring because they are difficult to distinguish from one another. Together these two species are often regarded collectively as "river herring".
- Throughout Its Range
In August 2017, we initiated a status review to determine if listing alewife under the ESA as endangered or threatened is necessary.