Since the early 20th century, Japanese cetacean biology relied heavily on fisheries for their materials. The work environment was challenging because research activities were controlled by industries and the fishery administration. I became a cetacean scientist in 1961 and worked mainly in the western North Pacific. There I witnessed the collapse of coastal populations of striped dolphins and sperm whales as a result of over-hunting. Nonetheless, my research revealed fascinating aspects of cetacean biology, which still await explanation, such as the following: neighboring populations of the same species having different breeding seasons, the role of reproductively senescent females in some toothed whales, the role of “social sex” in short-finned pilot whales, and the selective benefit of male Baird's beaked whales living longer than the females. New methodologies are required to address these questions. I propose to include the following aims for the conservation biology of cetaceans: to identify a community as a conservation unit, and to focus on conserving the cultural diversity and variability of such communities, and henceforth to focus increased research on understanding the contribution of individuals within a community. Today, marine mammal biologists of all fields need to pay more attention to conservation.