Meeting Abstract

S4-1.1  Thursday, Jan. 5  Dispersal in Marine Organisms without a Pelagic Phase WINSTON, Judith E.; Virginia Museum of Natural History

In contrast to marine organisms whose offspring go through an extended planktonic stage, the young of others develop directly into benthic juveniles or have non-feeding larvae which spend only a few hours in the plankton before settling. Yet, paradoxically, many such species have geographic distributions that are comparable to those of species with a pelagic dispersal stage. This paper reviews some of the ways in which these organisms can expand their distributions: drifting, rafting, hitchhiking, creeping, and hopping. Drifting applies to species in which larvae may be short-lived, but adults can detach or be detached from their benthic substratum and be passively carried to new areas. Many encrusting species can spread by rafting, larvae settling on natural or artificial floating substrata which are propelled by wind and currents to new regions. Hitchhiking applies to those attaching to vessels or being carried in ballast water to a distant region in which their offspring can survive. Other species can extend their distributions by hopping from one island of hard substratum or favorable sedimentary microhabitat to another, while creeping species extend their distributions along shores or shelves where habitats remain similar for long distances.