Evidence is beginning to accumulate that human development of coastlines and overfishing may be having deleterious effects on marine biodiversity. Although some biologists doubt marine extinctions, the possibility is being taken seriously by scientific organizations, who have been sponsoring conferences and workshops on the changing diversity of the oceans. Four federal agencies (NSF, NOAA, the Office of Naval Research, and DOE) have banded together to sponsor a National Research Council initiative to chart a research agenda.