资料来源 : pyDict

为产卵顺流而下的

资料来源 : Webster's Revised Unabridged Dictionary (1913)

Catadromous \Ca*tad"ro*mous\, a. [Gr. kata` down + dro`mos a
   running.]
   1. (Bot.) Having the lowest inferior segment of a pinna
      nearer the rachis than the lowest superior one; -- said of
      a mode of branching in ferns, and opposed to {anadromous}.

   2. (Zo["o]l.) Living in fresh water, and going to the sea to
      spawn; -- opposed to {anadromous}, and said of the eel.

资料来源 : WordNet®

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