The Collaborative International Dictionary of English v.0.48:

Sturgeon \Stur"geon\, n. [F. esturgeon, LL. sturio, sturgio,
   OHG. sturjo, G. st["o]r; akin to AS. styria, styriga.]
   (Zool.)
   Any one of numerous species of large cartilaginous ganoid
   fishes belonging to Acipenser and allied genera of the
   family Acipenseridae. They run up rivers to spawn, and are
   common on the coasts and in the large rivers and lakes of
   North America, Europe, and Asia. Caviar is prepared from the
   roe, and isinglass from the air bladder.
   [1913 Webster]

   Note: The common North American species are Acipenser
         sturio of the Atlantic coast region, Acipenser
         transmontanus of the Pacific coast, and Acipenser
         rubicundus of the Mississippi River and its
         tributaries. In Europe, the common species is
         Acipenser sturio, and other well-known species are
         the sterlet and the huso. The sturgeons are included in
         the order Chondrostei. Their body is partially
         covered by five rows of large, carinated, bony plates,
         of which one row runs along the back. The tail is
         heterocercal. The toothless and protrusile mouth is
         beneath the head, and has four barbels in front.
         [1913 Webster]

   Shovel-nosed sturgeon. (Zool.) See Shovelnose
   (d) .
       [1913 Webster]

WordNet (r) 3.0 (2006):

Acipenser transmontanus
    n 1: food and game fish of marine and fresh waters of
         northwestern coast of North America [syn: Pacific
         sturgeon, white sturgeon, Sacramento sturgeon,
         Acipenser transmontanus]