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]

The Collaborative International Dictionary of English v.0.48:

Chub \Chub\, n. [This word seems to signify a large or thick
   fish. Cf. Sw. kubb a short and thick piece of wood, and perh.
   F. chabot chub.] (Zool.)
   A species to fresh-water fish of the Cyprinid[ae] or Carp
   family. The common European species is Leuciscus cephalus;
   the cheven. In America the name is applied to various fishes
   of the same family, of the genera Semotilus, Squalius,
   Ceratichthys, etc., and locally to several very different
   fishes, as the tautog, black bass, etc.
   [1913 Webster]

   Chub mackerel (Zool.), a species of mackerel (Scomber
      colias) in some years found in abundance on the Atlantic
      coast, but absent in others; -- called also bull
      mackerel, thimble-eye, and big-eye mackerel.

   Chub sucker (Zool.), a fresh-water fish of the United
      States (Erimyzon sucetta); -- called also creekfish.
      [1913 Webster]

WordNet (r) 3.0 (2006):

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