What is "catadromous"

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. [1913 Webster] ||

a. 1 (context of a migratory fish English) that lives in fresh water and breeds in the sea 2 (context botany English) Of a fern in which the first veins in a frond segment are produced towards the base of the frond.

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