Catadromous
Catadromous , adjective
[Greek kata` down + dro`mos a running.]
1.
(Botany) 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.
(Zoology) Living in fresh water, and going to the sea to spawn; -- opposed to anadromous, and said of the eel.