Species Spotlight: Alewife
It’s spring on Long Island and that means the Alewife, our native species of river herring, returns to freshwater rivers and streams!
Alewife populations have dropped from historical levels across Long Island. Over fishing and by-catch are the main concerns in saltwater habitats, while migration barriers, such as dams and culverts, prevent migration inland. However, since the removal of obsolete dams and construction of fish passages, populations are recovering. You can help this species by volunteering with local organizations to monitor alewife populations and by always following your local fishing regulations!
For Alewife Activities + Family Resources, be sure to check out our Digital Education Initiative: The Alewife!
Alewife
Alosa pseudoharengus
Alewives have a dark bluish/green dorsal side and light silver sides with horizontal darker stripes.
The Alewife is an anadromous fish.
The Alewife is an ecologically and commercially significant species that faces threats such as migrationbarriers, bycatch and habitat degradation.
River dams can block Alewife migration to spawning grounds and are the biggest threat the species faces today.
Alewife
Scientific Name: Alosa pseudoharengus
Identification: Alewives are about 10-12 inches long, with a slender body and deeply forked tail. They have a dark bluish/green dorsal side and light silver sides with horizontal darker stripes. The head is broad and triangular and they have a dull black spot located behind the gills.
Diet: Alewives mainly feed on zooplankton, shrimp, small fish and fish eggs.
Habitat: The Alewife is an anadromous fish. Although it spends most of its life in saltwater, the Alewife migrates upstream to spawn in freshwater. They can be found along the Atlantic Coast of the US, but there are also many populations in landlocked bodies of water.
Find this Species: Each spring, adult fish migrate from the ocean and “run” up Long Islands river and streams to spawn in freshwater. In Suffolk County, the run happens in all the freshwater rivers and streams!
Interesting Facts: The average lifespan of the Alewife is 8- 10 years. They begin spawning at 3-5 years old, and have 4-6 migrations during their lifetime.
Alewives will travel up to 1,200 miles every spring to reproduce in the same rivers in streams where they were born.
Females produce up to 250,000 eggs but survival rate is about 1%.
Predators of the Alewife include marine mammals, larger fish, river otters, osprey and eagles. Alewife eggs are an important food source for other species.
Alewives are ecologically and commercially significant. Alewife is the preferred bait for lobstermen!
Watch this video to learn more about the Alewife run here on Long Island!