This award will support Dr. John S. Pearse of the University of California, Santa Cruz, to collaborate with Profs. Masashi Yamaguchi and Kiyoshi Yamazato of the University of the Ryukus, Okinawa, and Naomasa Kobayashi, of Doshisha University, Kyoto, for six months beginning in March, 1989. They will study the development of two tropical Indo-West Pacific species of sea urchins of the genus Diadema. In order to study the monthly gametogenic rhythms and how these rhythms are related to moonlight and tidal cycles, and how these rhythms affect fertility of these species, the researchers will 1) determine the monthly gametogenic rhythms of the species at different locations; 2) monitor populations to detect spawning events; 3) maintain animals in artificially illuminated laboratory conditions to simulate moonlight cycles and 4) attempt to rear the larvae of both species and, if possible, hybrids, through metamor- phosis. This cooperative project will provide Dr. Pearse with access to Japanese components of widespread and ecologically important members of the tropical shallow-water fauna, as well as to support from Japanese laboratories and researchers with experience in raising and studying these species. Since these sea urchins are prevalent, cause bioerosion, and create a nuisance for fishermen and swimmers, further understanding of their reproductive patterns may have important ecological effects.
