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American Shad Overview

Alosa sapidissimaIllustration of an American shad (Alosa sapidissima).

Life History and Distribution

  • American shad are a large, anadromous herring native to the eastern seaboard of North America. Adults can weigh between 0.9 kg and 5.9 kg (2 – 13 lbs). Each year between April and June, adult American shad leave the sea and enter large, coastal rivers. They spawn in calm waters, and females produce between 30,000 and 616,000 eggs, which sink to the bottom of the river. After hatching, juvenile American shad spend the summer months growing in freshwater before making a migration out to sea in the fall. Juvenile American shad spend between two and five years at sea growing to adulthood before making the return trip to spawn in rivers. In the southern part of their range, American shad are semelparous; they spawn once and die, like salmon in the Pacific Northwest. In the northern part of their range, American shad are iteroparous; they can make spawning migrations several times in their lives. American shad are naturally distributed from the St. Johns River in Florida, USA to the St. John River in Newfoundland, Canada. Biologists introduced them to the west coast of the United States in late 1800s, and they are now present from northern California to southern Alaska.

Importance in Maine

  • American shad provided a valuable food resource to the Native American tribes and colonial settlers of Maine. The fishery in the Gulf of Maine annually produced over 2.5 million pounds of shad in the late 1800s, with over half of that total being landed in Maine and the remainder being landed in Nova Scotia and Massachusetts. By 1931, these historic amounts had declined to just 157,000 pounds in Maine, 147,000 pounds in Massachusetts, and 237,000 pounds in Nova Scotia. Commercial landings of American shad have continued to decline throughout their range, and totaled just 220,460 pounds for the entire Atlantic coast in 2005. There is no longer a commercial fishery for American shad in Maine; however they are increasingly being recognized as an exciting sport fish, with some going so far as to call American shad “the poor man's tarpon” because of their ability to leap and fight.


  • A 2007 report by the USFWS found that American shad populations throughout their range were at all times lows. Although some larger populations (e.g. the Merrimack River and the Connecticut River) are stable, Maine populations were listed as continuing to decline at that time. The primary causes for low shad populations are thought to be overfishing, pollution, and habitat loss due to dam construction. Dams are particularly troublesome because many traditional fish ladders do not pass American shad effectively.

Current Restoration Efforts

  • The Waldoboro Hatchery produced American shad fry for stocking in the Androscoggin, Kennebec, and Sebasticook Rivers from 1992 to 2008; however, the program ended in 2009 due to lack of funding. The Maine Department of Marine Resources currently monitors American shad usage of fish passage facilities on all major rivers in the state, including video monitoring at the Brunswick fishway. New fishways have recently been constructed on the Saco River (2012) and the Penobscot River (2014) with the goal of increasing American shad passage. 

Links to Useful Documents

Maine DMR American Shad Habitat Plan

Fisheries and Oceans Canada's Fact Sheet on American Shad

USFWS Species Profile: Shad and River Herring

Prepared by:

George Maynard
University of Maine
American Fisheries Society Student Subunit

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