White Perch, Sea Perch
The white perch resembles its larger relative, the striped bass, in the number, outline, and arrangement of its fins, and in its deep caudal peduncle without longitudinal keels. White perch are occasionally as much as 15 inches long, 5 inches or more deep, and 2 pounds or a little more in weight; but the average is 8 to 10 inches long and 1 pound in weight, or less. The white perch is much more closely restricted in its seaward range than the bass, for while they are taken in undiluted sea water along southern New England, and at various other localities thence westward and southward, they are much more plentiful in ponds connected with the sea, in the brackish water of bays behind barrier beaches, in estuaries, and in river mouths. Run in salt and brackish reaches of the Parker River. Also occur landlocked in fresh-water ponds in many places. Swarms of young perch have been seen following the alewives around the shores of ponds on Marthas Vineyard, eating their spawn as it was deposited.
From Fishes of the Gulf of Maine by Bigelow and Schroeder (1953) online courtesy of MBL/WHOI http://www.gma.org/fogm/Morone_americana.htm
Al Bezanson
Good Morning Gloucester 