The Collaborative International Dictionary of English v.0.48:

Dogfish \Dog"fish`\, n. (Zool.)
   1. A small shark, of many species, of the genera Mustelus,
      Scyllium, Spinax, etc.
      [1913 Webster]

   Note: The European spotted dogfishes (Scyllium catudus, and
         Scyllium canicula) are very abundant; the American
         smooth, or blue dogfish is Mustelus canis; the common
         picked, or horned dogfish (Squalus acanthias)
         abundant on both sides of the Atlantic.
         [1913 Webster]

   2. The bowfin (Amia calva). See Bowfin.
      [1913 Webster]

   3. The burbot of Lake Erie.
      [1913 Webster]