9402971 Bowen This project will quantify genetic variation and evolutionary relationships within the Clupeoid genera Sardinops and Engraulis. These two taxa, commonly known as sardines and anchovies, are pelagic filter feeders typically found in warm-temperate coastal waters and have great commercial importance. The taxonomic and systematic distinctions between regional forms of these two genera remains unresolved despite the intense interest in means by which these fish have been dispersed throughout the ocean. This study will use mtDNA geneologies to elucidate the pattern of colonization among regional forms. A second goal of this study will be to estimate mtDNA clonal diversity within regional forms of Sardinops and Engraulis. Finally, mtDNA data will be used to assess the level of gene flow among putative sardine stocks along the west coast of North America. These results have strong implications for fishery assessment, as reproductive populations are the fundamental units of species management.