The Collaborative International Dictionary of English v.0.48:

Huso \Hu"so\, n. [NL., fr. G. hausen, and E. isinglass.] (Zool.)
      (a) A large European sturgeon (Huso huso or Acipenser
          huso), inhabiting the region of the Black and Caspian
          Seas. It sometimes attains a length of more than
          twelve feet, and a weight of two thousand pounds.
          Called also hausen and beluga. It is the source of
          the finest and most esteemed caviar.
      (b) The huchen, a large salmon.
          [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Huch \Huch\, Huchen \Hu"chen\, n. [G.] (Zool.)
   A large salmon (Salmo hucho or Salvelinus hucho)
   inhabiting the Danube; -- called also huso, and bull
   trout.
   [1913 Webster]