The ocean is the cradle of life It is where marine organisms have repeatedly flourished and declined for long eons. The destiny of marine life depends on environmental factors. Up to the present time, humans have thought that the ocean was an infinite repository of living marine living resources. However, rapidly developed technology has shown us that they are no more infinites. To utilize marine living resources continuously, we need to understand marine ecology, a field that deals with the relationships among the environment and organisms, and among marine organisms. the marine biology department offers various courses in the ecology of phytoplankton, zooplankton, fish, and benthos, which inhabit areas of the ocean from the intertidal zone to the deep ocean. For the sustainable development of living marine resources, the goals of the study are to understand the principles of marine ecology and the roles of marine organisms in the ocean and to discover and utilize the inherent genetic characteristics of marine organisms via molecular techniques.