What is An Alewife?

Alewives are members of the herring family. They spend most of their lives at sea, and migrates up freshwater rivers to spawn. Alewives range from the Canadian Maritime Provinces to North Carolina. At sea, they spend most of their time north of Long Island and Cape Cod, mixing with other small, pelagic fish over the continental shelf. They return to spawn between the ages of 3 and 5, presumably to the river in which they were born, or nearby, and can live 8 to 10 years. Spawning runs occur in the spring, and fish can make multiple spawning runs over their lifetime. A small fish of humble appearance, alewives are incredibly important ecologically. They are perhaps most important as a forage fish, serving as prey for numerous predators while at sea (such as cod, tuna, dolphins) in estuaries (striped bass, bluefish, weakfish, harbor seals) and in rivers (ospreys, white perch, herons, river otters). Also, alewives help deliver carbon and energy upstream against river flow to freshwater habitats, thereby replenishing what is lost as water moves matter out to sea. Alewives have been listed as Species of Concern by NOAA, which reflects the possibility that they will become endangered in the absence of concerted conservation efforts. Alewife populations on Long Island have not fared much better. Efforts are underway to restore alewives by providing access to historical spawning grounds that have been lost. Friends of the Bay is preparing plans to modify impassible culverts and install fish ladders to help fish reach valuable spawning habitat.