Alosa pseudoharengus (Alewife)

Animal Fish
Family: Clupeidae
Classification: Regulated


The Alewife, also called grey herring or golden shad, is a small herring. They are an anadromous species, although there are some landlocked populations around the Great Lakes. When anadromous, the fish can reach 12 - 15 inches in size, and females lay from 60,000 to 100,000 eggs. When landlocked the fish tend to grow only to about 6 inches, and the females will lay 10,000 to 12,000 eggs. When landlocked they will feed on the eggs and young of other fish, as well as their own. They also selectively feed on the larger species of zooplankton. They are a forage fish for larger species. However eating them has been found to cause reproductive failure in landlocked salmon and trout species. Alewives contain enzymes that diminish the ability to store thiamin in tissues. The thiamin deficiency causes an illness called Cayuga Syndrome, which can cause 100 % mortality in larval offspring of landlocked salmon and trout.

Alewife are not considered game fish or a food fish, although they are sometimes harvested for pet food or used for chumming. When landlocked they sometimes experience massive die-offs. Possibly related to the water getting warmer. If anadromous populations were to become established they could interfere with native shad, smelt, and herring populations.