Shad and River Herring

USGS is working to identify an improved fishway entrance design for two at-risk species, blueback herring ( Alosa aestivalis ) and alewife ( Alosa pseudoharengus ).

Dams can be found in just about every major river, and for good reason. Society has received many benefits like flood control, hydropower, water supply storage, and places to recreate. However, many fish and other life in our rivers can’t swim around these barriers. Often, the best spot for a fish to live and reproduce is out of reach because they can’t pass by a dam. This has not gone unnoticed...

American Shad ( Alosa sapidissima ), Blueback Herring ( Alosa aestivalis ), and Alewife ( Alosa pseudoharengus ; collectively “alosines”) once supported large fisheries along the U.S. Atlantic Coast. However, impassable migration barriers, declines in habitat quality, and exploitation have led to declines in many spawning populations. Substantial resources have been invested to support the...

American Shad are the most numerous and economically important anadromous species on the east coast of the United States. Yet in many river systems their populations have experienced declines, primarily due to the impacts of dams and habitat loss.