This award will support Professors Romuald N. Lipcius and Brian W. Meehan of the Virginia Institute of Marine Science of the College of William & Mary, in a research collaboration with Professors Karl Aiken of the University of the West Indies and Milton Haughton of Jamaica Fisheries, both in Jamaica. The investigators intend to use a recent technique (mitochondrial DNA restriction fragment analysis) to assess genetic and population hetero-geneity in statistically sound samples from selected populations in Jamaica, Mexico, the Bahamas, and Bermuda of the spiny lobster Panilirus argus. The key unresolved issue concerning the ecology and fishery biology of the spiny lobster and other widely dispersed marine species in the Caribbean pertains to the scales and degree of geographic differentiation of populations. Resolution of this issue could lead to major advances in our understanding of ecological relationships (e.g., recruitment dynamics) and management of this and other important Caribbean marine fisheries. Spiny lobsters inhabit coastal waters from Bermuda to Brazil, and their recruitment is affected by major oceanic current systems. The potential exists for pelagic transport of larvae throughout the Caribbean basin, thereby producing pan-Caribbean homogeneity in population structure. Alternatively, larvae could be retained within local gyres, thereby producing geographic differentiation. In order to assess the degree and scales of geographic differenti- ation, it is critical to characterize population heterogeneity across and within geographic areas. This Science in Developing Countries Program award will provide the requisite information for (1) further investigations of geographic differentiation in the spiny lobster, (2) investigations of recruitment processes in widely dispersed Caribbean species, and (3) help to support the development of effective pan-Caribbean fisheries management.