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American Shad
Alosa sapidissima
Photo credit: US Fish and Wildlife
Habitat requirements and life history:
From USFW description (http://www.fws.gov/r5cneafp/shad.htm)
"American shad (shad) is the largest member of the herring
family, averaging between 17 and 24 inches in length and between
3 and 6 pounds in weight at sexual maturity. It is a schooling
species and highly migratory. Shad are found along the Atlantic
seaboard from Labrador to Florida. Most abundant on the East
Coast from Connecticut to North Carolina, shad have spawned,
historically, in almost every major river along the Atlantic
Coast. Shad are river- specific; each major river along the
Atlantic Coast appears to have a discrete spawning stock."
Like Alewife, American Shad are anadromous fish, breeding
in freshewater streams. In Massachusetts, shad spawning runs
generally occur in May. They spawn in the late afternoon or
evening in shallow areas with sand or gravel bottoms. The
young form schools and feed in the river until they are about
four inches. Outmigration to the sea takes place in September
to early November when water temperatures drop to 66 degrees
(F).
During the summer, adults that survive spawning along with
subadults migrate to the Gulf of Maine (or Nantucket Shoals
for southern populations) and remain there throughout the
summer and early fall. Most move out of the Gulf of Maine
in fall as water temperatures decline. During the winter they
congregate offshore, between southern Long Island and Nantucket
Shoals.
Adult shad are largely filter feeders, gathering zooplankton
on their gill rakers, but they will also feed on shrimp and
small fishes. The young-of-the-year feed on small zooplankton
and insects. (Sources: Hartel, Halliwell, and Launer, 2002.
"Inland Fishes of Massachusetts"; Massachusetts
Wildlife No. 2, 2000, Special Fishing Issue; U.S. Fish
and Wildlife Service, June 1985, Biological Report #82(10.88)
Habitat Suitability Index Models and Iinstream Flow Suitability
Curves: American Shad)
Total Length:
usually 17 - 24 inches (can grow larger).
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