a. [f. Gr. κατάδρομος (f. κατά down + -δρομος running) + -OUS. Cf. ANADROMOUS.]
1. Zool. Of fishes: Descending periodically from the upper to the lower reaches of the river, or to the sea, in order to spawn; as the Eel.
1883. Fisheries Exhib. Catal. (ed. 4), 97. Fresh-water fishes may be … ‘catadromous,’ or such as reside in fresh waters.
2. Bot. (See quot.)
1881. J. G. Baker, in Nature, XXIII. 480. Milde’s classification of ferns into a catadromous and anadromous series according as to whether their lowest secondary branches originate on the posterior or anterior side of the pinna.
