Feeding behaviour of Caribbean Scyphomedusae: Cassiopea frondosa (Pallas) and Cassiopea xamachana Bigelow

LARSON, R.J., 1997. Feeding behaviour of Caribbean Scyphomedusae: Cassiopea frondosa (Pallas) and Cassiopea xamachana (Bigelow). Studies Nat. Hist. Caribbean Region 73, Amsterdam 1997: 43-54. Cassiopea frondosa and C. xamachana are carnivorous. Prey are filtered from the water by the pumping activity of the umbrella. Prey, predominantly small epibenthic crustaceans (0.2- 10 mm in length) are caught mostly by interception. However, some prey may impact on the oral surface through turbulence or by their own locomotion. Prey capture was essentially the same for both species, except that the vesicles take an active part in prey capture only in C. frondosa. Ingestion occurred after the digitate-fringed lips of the funnel-shaped oral ostia opened. The digitata with attached prey then bent inward towards the ostium and subsequently swept into the ostium, and transported to the stomach by ciliary activity. Prey were similar for both medusae. Copepods, chiefly harpacticoids, with fewer cyclopoid and calanoid species, were most numerous, ostracods were second in numerical abundance, followed by tanaids and chironomids. Other prey consisted of gammaroids, nematodes, mysids, miscellaneous eggs, veligers, chaetognaths, cumaceans, foraminifera, and others. On a weight basis, harpacticoid copepods, tanaids, and chironomids made up = 30% each, followed by mysids at = 10%.