sea lamprey

from The American Heritage® Dictionary of the English Language, 5th Edition.

• noun A large parasitic lamprey (Petromyzon marinus) found in Atlantic coastal waters and in the Great Lakes, where it preys on whitefish, lake trout, and other fish.

from the GNU version of the Collaborative International Dictionary of English.

• (Zoöl.) The common lamprey.

from Wiktionary, Creative Commons Attribution/Share-Alike License.

• noun A parasitic lamprey found in Europe and North America, Petromyzon marinus.

from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.

• noun large anadromous lamprey sometimes used as food; destructive of native fish fauna in the Great Lakes