NATURAL HISTORY OF THE BENTHIC CTENOPHORE VALLICULA MULTIFORMIS (CTENOPHORA, PLATYCTENIDA) IN KANEOHE BAY, HAWAII

A population of benthic, platyctene ctenophores previously recorded only from the Caribbean was studied in Spring 1994. V. multiformis occurred in dense patches (to 10,000 ind./m sq) on several species of algae on floating docks. Animals 2-20 mm diam deployed tentacles up to 60x the body length, forming a dense 'population filter' that appeared capable of exerting substantial predation pressure on plankton communities. In a 2.5-d experiment, a mean ingestion rate of 10 Artemia/ctenophore/h supported an individual growth rate of 27%/day, indicating that high feeding and growth rates are possible when prey are available. The size frequency distribution of ctenophores collected from algal substrates was strongly dominated by small individuals, possibly resulting from the tendency of this species to fragment and regenerate. Dramatic reductions in ctenophore populations corresponded to substantial reductions in salinity during heavy rains. Rapid recovery from such depletions was likely accomplished by fragmentation and asexual reproduction, although large animals also contained sexual embryos in late spring. I thank G.C. Fiedler and C. McGeorge for lab and field assistance.