The Collaborative International Dictionary of English v.0.48:

Tautog \Tau*tog"\, n. [The pl. of taut, the American Indian
   name, translated by Roger Williams sheep's heads, and written
   by him tauta['u]og.] (Zool.)
   An edible labroid fish (Haitula onitis, or Tautoga
   onitis) of the Atlantic coast of the United States. When
   adult it is nearly black, more or less irregularly barred,
   with greenish gray. Called also blackfish, oyster fish,
   salt-water chub, and moll. [Written also tautaug.]
   [1913 Webster]

WordNet (r) 3.0 (2006):

Tautoga onitis
    n 1: large dark-colored food fish of the Atlantic coast of North
         America [syn: tautog, blackfish, Tautoga onitis]