Once, Sato-umi supported people's lifestyles in various ways. They nurtured shellfish and seaweed, and they were also used by people in the local community as beaches and recreation areas.
Sato-umi produce clams, seaweed and other foods. In the past, many people came to the Nakatsu Tidal Flat in Oita Prefecture at sunset to dig clams to eat as a side dish with dinner.
Seaweed collected at the Sato-umi was used as fertilizer, and pine needles and the driftwood that washed up on the shore were used as fuel to heat baths and kitchen stoves. Pine trees were planted along the coast to serve as windbreaks, and they also functioned as woodlands for fish bleeding. Even today in the Seto Inland Sea, some people still use eelgrass to heat natural stone baths and employ oshiami fishnets to fish in the eelgrass beds. However, nowadays there are very few places where such activities can be seen.
Since the days of Japan's period of rapid economic growth, many coastlines in Japan have been turned into manmade coastlines through reclamation, development and so on. Harbor facilities and industrial facilities have been located in these areas, and therefore there are fewer and fewer places where people can come in contact with the ocean. As a result, people have become separated from and have less interest in the ocean. Because of this decrease in interest, they are no longer even aware of the current situation, in which seawater has become polluted by household wastewater and litter is strewn along the coastline, adversely affecting both scenic beauty and the habitats of living things.
In order to create opportunities for people to come in contact with and rekindle an interest in the ocean, NPOs, local governments and other entities are conducting various activities aimed at the general public. These include nature walks, "hands-on" activities, coastal cleanup efforts and so on.