Since ancient times, the lives of the Japanese people have been accompanied by the tangible and intangible blessing of the sea. In recent times, however, Japanese consumers have been eating fish less than they once did. At the same time, the species of fish that can be harvested from the seas around Japan have been adversely affected by climate change, and fish catches have been declining steadily. Will future generations of Japanese be able to enjoy the kind of diversity and abundance of the sea as previous generations?

To help answer this question in the affirmative, the Obayashi Project Team set to work on the idea of an "ocean farm," a project intended to protect the bountiful sea and Japan's diverse fish-centered food culture. It proposes the future of aquaculture and fisheries, utilizing the regulating power of nature to protect the sea and nurture fish, just as animals are raised in a spacious natural pasture in a relaxed manner.

Japan's Fishing Industry Today

Japan is an island nation surrounded by the sea. The ocean currents flowing around Japan help create one of the world's greatest fisheries. In turn, the immense variety of fish and shellfish in these waters has fostered the development of a rich cuisine making use this abundance. In recent times, however, climate change and other factors have reduced fish catches in Japanese waters as well as changing the fishing grounds and species of fishes themselves. Japan now faces the challenge of stabilizing its supply of marine products to develop a healthy fisheries industry.

After the Second World War, the Japanese fisheries industry expanded first from Japan's coastal waters to offshore fishing grounds, and from there to open sea, and its marine products production (including aquaculture) peaked in 1984. After 1984, however, countries around the world set up exclusive economic zones (EEZ) in the ocean waters off their shores, effectively keeping Japanese fishing vessels away from overseas fisheries. Catches of Japanese sardines (maiwashi), a mainstay of Japan's fishing industry, went into decline. With the deterioration of fishing grounds from around 1988 to 1995, marine products production suffered a steep decline.

Meanwhile, by 2020 aquaculture (fish farming) production had increased to nearly 24% of total marine products production. However, in time, among the newly emerging Asian economies, such as China, Indonesia and Vietnam, aquaculture production of these nations increased rapidly and came to represent about 60% of overall marine production. It is an undeniable fact that Japan's aquaculture industry lags far behind the rest of the world.

According to the FY2022 Annual Report on the Developments in Japan's Fisheries (Fisheries White Paper) issued by the Fisheries Agency, the number of fishery workers in Japan plummeted from 699,000 in 1961 to 129,000 in 2011 and is expected to decline to 92,000 in 2033. One encouraging sign is that in an industry where over the long term more the half of the workers are over the age of 50, beginning in the middle of the 2000's, there has been a consistent and ongoing increase in the number of newly-hired younger workers.

In global terms, fishing is a growth industry, and fisheries production has doubled in the course of the last 30 years. In Japan, a nation surrounded by bountiful fishing grounds with the potential to support high levels of fisheries growth, the government is currently promoting resource management and the use of information technologies to turn around the fishing industry and transform it into a growth industry. If the industry can properly manage resources and improve productivity through smart technology and other means, it will once again attract attention as a growth industry.

There is a close connection between the bountiful fishing grounds surrounding the Japanese islands and Japan's culture of seafood cuisine. The Japanese have for centuries created and become familiar with dishes that bring out the innate delicious flavors of seafood. One of the reasons that the Japanese people have among the world's longest life expectancy is the prevalence of healthful fish in the Japanese diet. And in recent years, there has been a worldwide boom in healthy Japanese food and an accompanying expansion of Japanese-style fish-based food culture.

Nevertheless, Japanese consumers continue to drift away from eating fish. According to the Ministry of Agriculture, Forestry and Fisheries' "Food Balance Sheet," annual per capita consumption of edible fish and shellfish (net food supply) peaked in FY 2001 and has been on a sharp downward trend since then, falling below levels of meat consumption for the first time in FY2011.

Turning to worldwide trends, from 1970 to 2019, annual per capita consumption of edible fish and shellfish doubled. This trend was especially evident in China, with consumption increasing by a factor of 8.4, and in Indonesia where it increased nearly four-fold. Although Japanese seafood consumption remains about twice that of the global average, Japan is the only major country in the world and in its region where fish consumption is trending downward.

There have also been changes in the types of fresh seafood typically purchased by consumers. According to the Fisheries White Paper, Japanese consumers in 1989 bought large quantities of horse mackerel and mackerel pike beside along with squid and shrimp. In recent years, however, salmon, tuna, and yellowtail, which are often sold as fillets, have become more popular. For many years, the seafood consumed in each part of Japan were the fish and shellfish that were available in the waters off that particular region. With the development of distribution networks and refrigeration technology and at the same time the increased demand for fish that can be easily prepared at home, a wide variety of seafood is now consumed throughout Japan.

When consumers compare fish with other meat products, although fish comes out ahead in terms of its health benefits, it also has a reputation as being more expensive than meat and rather hard to prepare. The fact that Japanese households are consuming less seafood does not mean that people are consciously turning away from seafood or that they have stopped liking fish altogether.

In order to revitalize the fishing industry, it will be critically important to effectively disseminate information to encourage people to eat more fish.

Resource assessments by the Food and Agriculture Organization of the United Nations have identified a worldwide and growing trend toward overfishing (fish catches that exceed the oceans' reproductive and regenerative capacity). But there are factors other than fishing that impact fish stocks: the development and use of coastal areas, water runoff from coastal regions, and broad changes in the marine environment associated with climate change are all hurting the diversity of marine life.

Meanwhile, the world's population is expected to grow from its current level of 8 billion people (2022) to some 9.7 billion people by 2050. There is concern about the lack of food to support this increase, especially high nutrient foods such as animal protein. Against a backdrop of increasing instability in world food supplies, Japan turned its attention to ensuring its ability to feed its own people, and is promoting the fisheries industry.

The goal of new Basic Plan for Fisheries approved by the Cabinet in March 2022 is to "achieve sustainable growth of the fisheries industry and to revitalize fishing villages." To attain these goals, the Plan proposes three basic strategies: (1) steadily implementing fisheries resource management that considers changes in the marine environment; (2) promoting growth of the fisheries industry in the face of growing risks; and (3) promoting the revitalization of the fishing villages that support regional communities.

In addition, as measures to be promoted, the utilization of smart fisheries technologies such as ICT and initiatives related to blue carbon were mentioned. The Basic Plan sets self-sufficient targets for Japan of 94% for edible fish and shellfish, 76% for all fish and shellfish, and 72% for seaweed by FY2032.

Over the past 100 years, there have been major changes in the environment of Japan's fishing grounds with average seawater temperatures in coastal waters rising by 1.24℃. With fish catches declining, hopes are high for aquaculture and cultivated fisheries(*1).

*1　Cultivated fisheries: A fishing method in which fry are raised by human hands during the period when it is difficult for fish and shellfish to grow in the natural environment from eggs to fry or young shellfish. The fry are then released into the natural environment, allowing the sea to function as a "nurturing fishing ground" from which the grown fish are harvested.

As mentioned above, the oceans play a vital role in producing highly nutritious animal protein. In recent years, shallow sea areas are increasingly viewed as blue carbon ecosystems that serve as carbon dioxide sinks. "Blue carbon" speaks of carbon that is taken up by coastal and marine ecosystems and stored in the biomass and underlying soil of these ecosystems. In other words, the seaweed beds where seagrasses and seaweeds flourish serve as carbon sinks, separating and storing carbon dioxide in the form of blue carbon. As seaweed beds increase, they provide habitats for a variety of organisms that attract fish and other predators which prey on the organisms living there. The hope is that this cycle can create "nature-positive" ecosystems where the seaweed beds contribute to the global environment while helping to reverse the loss of biodiversity in the oceans.

The rapid loss of biodiversity is seen as a serious threat to human survival, along with and in conjunction with climate change itself.

At the G7 summit in 2021, member nations set a target of effectively conserving at least 30% of the global terrestrial and marine habitat as healthy ecosystems by 2030, the so-called "30x30" goal. In 2022, the Kunming-Montreal Global Biodiversity Framework was adopted by 15th Conference of the Parties (COP15) to the Convention on Biological Diversity. The Framework calls for a shift toward a "nature-positive" world and to accelerate the move toward a world in harmony with nature by 2050.

While aquaculture offers a great deal of promise, it also carries risks. One concern is that aquaculture can cause ocean waters to become over-nourished (excessively eutrophic), resulting in foul odors, blue tides, and other phenomena that adversely impact human populations and the habitats of other living creatures. In its response, however, Japan may be going too far in its approach to environmental degradation, so much so that ocean waters have become too clean, effectively scrubbed of nutrients, so that nori and wakame seaweed, plants which have high nutrient requirements, cannot grow, which in turn inhibits the growth of clams and other bivalves.

Given the risks associated with aquaculture, sustainable aquaculture methods must be developed that prevent the pollution of marine environments by the excessive release of nutrients. One approach is "integrated multi-trophic aquaculture" (IMTA) which makes more effective use of residual fish feed and nutrient salts and combines organisms from different trophic levels in the food chain to create a balanced system.