PATTERNS OF ABUNDANCE FOR MNEMIOPSIS IN US COASTAL WATERS - A COMPARATIVE OVERVIEW

An examination of plankton and environmental data for several coastal systems in the United States indicates that high biomasses of Mnemiops is spp. are associated with warm waters and an abundance of prey copep ods such as Acartia tonsa. Field data from several locations suggest t hat temperature, food availability, and predators may all be vital in determining the observed patterns of ctenophore abundance. Although cu rrently there is insufficient quantitative information to make definit ive conclusions about the control of ctenophore population dynamics in any of these systems, a comparison of patterns of abundance implies t here may be a latitudinal gradient in the relative importance of tempe rature and food availability. In the north, where annual temperature c ycles are likely to have the greatest influence, there is a relatively short, but intense, population explosion of M. leidyi in the late sum mer and early fall. In the warmer southern waters, the occurrence of M . mcrradyi seems to be more closely linked to prey availability, and c tenophore biomass is generally lower. Predation may be of fundamental importance to the patterns of abundance for the two species of Mnemiop sis throughout their ranges, but presently is poorly documented in mos t systems.