This book explores the nature of marine conservation based on the case study of Hinase, a fishing village in Okayama, Japan. It focuses on the fishers’ self-motivated eelgrass restoration activity which has been continued for more than 30 years. This activity in Hinase recently attracted international attention as a case under the name “Satoumi” and “Marine Protected Areas” in several governmental reports, but detailed information, such as the historical background and social structure of Hinase, has not yet been analyzed. This book, therefore, fulfills this gap by providing its ethnographic information. In addition, this book offers some points for critical thinking by concluding that marine conservation activities cannot always be evaluated or arranged under the standardized approach with limited time and space. This viewpoint reaffirms the importance of local initiative and highlights the value of qualitative research to seek the way forward for promising marine conservation. This book is suitable for an academic audience in the field of social sciences, such as applied anthropology, as well as ecologists, government officials, environmentalists, and citizens who are interested or engaged in environmental issues or natural resource management.