Source : Webster's Revised Unabridged Dictionary (1913)

Anadromous \A*nad"ro*mous\, a. [Gr. ? running upward; ? + ? a
   running, ? to run.]
   1. (Zo["o]l.) Ascending rivers from the sea, at certain
      seasons, for breeding, as the salmon, shad, etc.

   2. (Bot.) Tending upwards; -- said of terns in which the
      lowest secondary segments are on the upper side of the
      branch of the central stem. --D. C. Eaton.

Source : WordNet®

anadromous
     adj : migrating from the sea to fresh water to spawn [ant: {catadromous},
            {diadromous}]