ENVIRONMENTAL PROBLEMS AND ENVIRONMENTAL MANAGEMENT OF JAPANESE COASTAL WATERS:
AN ECOSYSTEM PERSPECTIVE

Ocean Research Institute
University of Tokyo

ABSTRACT

The coastal marine environment of Japan is characterized by its high biological productivity. This productivity contributes to generally high fishery yields. However, both the biological productivity of coastal ecosystems and the productivity of coastal fisheries are being threatened by substantial changes in the coastal marine environment. This situation is making it increasingly imperative to take an ecosystems approach to management of the coastal marine environment.

Pollution due to rapid industrial development and urbanization is a primary cause of the degraded condition of the coastal environment. Besides the direct effects of pollution, indirect effects such as red tides, oxygen depletion in the bottom waters, and oil contamination also contribute. Furthermore, engineering projects such as dredging, reclamation, and construction of marine facilities take their toll. Of particular concern to the fishing industry is the destruction of coastal nurseries. Most commercially valuable species spend their larval and juvenile stages in coastal nurseries such as tidal flats and seaweed beds.

In the context of global issues such as the explosive growth of the human population, wise use of renewable marine living resources has become indispensable to the goal of sustainable development. Sustainable development implies a balance between a short-term production efficiency goals and long-term maintainance of ecological integrity goals. The goal of this paper is to briefly describe some of the present environmental problems in Japanese coastal waters, especially in relation to the fishing industry, and to discuss mitigation and management of these problems from an ecosystem perspective.

CONTENTS

Japan's coastal waters are characterized by their highly diversified collection of ecosystems and their high biological productivity. The high biological productivity, which in turn often contributes to high- yielding coastal fisheries. Biological productivity and coastal fishery yields have been on the decline in recent decades, though. The major sources of these declines are related to industrialization and urbanization, and some are related to fishing practises.

Traditional coastal fishery practices have been partly responsible for maintaining the health productivity of the coastal waters. In this sence, as will be argued later in the paper, development of sustainable coastal fisheries have a key role to play in the conservation and proper management of the marine environment in Japan. However, the modern coastal fishery industry has often contributed to the damage of coastal habitats and ecosystems through their fishing operations, and through overfishing and by-catch problems (Nakata, 1995). In addition, the overloading of organic materials, such as leftover food and fecal pellets from aquaculture grounds, have degraded the water and bottom area quality in semi-enclosed bays.

Fishing practises, however, are not the most serious threat to Japanese coastal waters. Industrialization and urbanization are more serious threats. In the postwar period pollution caused by the tremendous industrial development and increased urbanization, along with secondary effects of industrialization and urbanization such as red tides, oxygen depletion in the bottom waters, and oil contamination have considerably degraded Japanese coastal environments (Table 1). In addition, engineering projects, such as dredging, reclamation, and construction of marine facilities, have led to the loss of coastal nurseries and habitats. According to the 4th National Survey on the Natural Environment conducted during 1988-1992 by the Nature Conservation Bureau of Japan Environment Agency, the total loss of tidal flat lands between 1978 and 1992 was about 4,000 ha, which is equivalent to about 8 percent of the existing tidal flat areas. Another source reported that about 40 percent of the tidal flats that existed in 1945 were lost by 1988 (Kikuchi, 1993). Since most commercially valuable coastal fish species spend their larval and juvenile stages in coastal nurseries such as tidal flats and seaweed beds, it is essential to preserve these areas to maintain the viability of the coastal fishing industry.

Concentrations of some pollutants in the marine environment have improved since the 1970s when enforcement measures were strengthened in Japan. However, concentrations of other pollutants, including some heavy metals and organic contaminants (e.g., PCBs, PAHs and TBTs), have expanded and intensified. Though contamination by toxic chemicals in general has improved in Japan and other developed countries due to strong regulatory measures, the same can not be said of developing countries where rapid economic growth and industrial development is causing toxic chemical pollution to become severe (Tanabe, 1995).

On top of the above problems in Japanese coastal waters, in recent years some of the shallow seas in the northern part of Japan have been suffering from a phenomenon known in Japanese as "isoyake" (or sea desert). Isoyake occurs when sublittoral marine algae such as Eisenia bicyclis (Phaeophyta) are replaced by dense crustose coralline red algae (Taniguchi, 1991), resulting in a rapid reduction in productivity and biodiversity (Taniguchi, 1991). Although the exact cause of isoyake has not yet been identified, there is an urgent need to develop methods to restore the original marine forests of E. bicyclis in isoyake-affected areas.

In a global context, sustainable use of renewable marine living resources is indispensable for the future development of human society. In general, economic development aims to maximize the short-term benefits, whereas maintenance of ecological integrity aims to minimize long-term loss. Sustainable development seeks to balance economic goals with ecological integrity. This applies to sustainable development of coastal waters as well as other air, land, and water resources. An optimal development strategy should consist of both the short-term goal of raising production efficiency and the long-term goal of restoring and maintaining ecological quality. It is not easy to put this into practice, though.

In Japan, for example, there is a growing interest in pursuing sustainable development by enhancing the proper ecological functioning of aquatic environments. Pilot projects have recently been started which aim to restore and create fishery industry-related coastal habitats (Nakamura, 1991; Itosu, 1993). , but most of these projects focus mainly on engineering solutions to productivity enhancement, not ecologically-based solutions. The goal of this paper is to briefly describe some of the present environmental problems in Japanese coastal waters, primarily in relation to the fishing industry, and to discuss mitigation and management of these problems from an ecosystem perspective.

Among the factors controlling environmental carrying capacity of coastal living resources, dissolved oxygen (DO) concentration is the most critical (Nakata, 1991). In Japan the formation of DO-depleted waters near the bottoms of some hypereutrophicated bays has significantly affected the benthic living resources of the bays (Fig. 1). When nutrient loads from the land are small, eutrophication can increase fishery production. And the fishery catches can contribute to the removal of organic products from the bays. However, when the nutrient loads exceed a certain limit there emerge negative feedback processes. Eutrophication is succeeded by rapid growth of phytoplankton (outbreaks of red tide, etc.). This leads to an increase in the organic flux to the bottom waters. Increased organic inputs in turn deplete the bottom waters of oxygen. And this further accelerates eutrophication through nutrient regeneration from the bottom. The DO depletion damages the habitats of fishery resources, and inhibits removal of the organic products.

Figure 2 shows annual changes in nutrient loadings from the land around Osaka Bay, a bay representative of a heavily urbanized region, from 1955 to 1982. Both nitrogen and phosphate loadings to Osaka Bay rapidly increased until the early 1970s. In the early 1970s phosphate began to to decline, but nitrogen maintained an increasing trend. There is concern that the difference in the phosphate and nitrogen loadings could lead to problems which may affect biological production in the bay due to a change in the overall nitrogen-phosphate ratio. In general, primary production in the bay seems to have increased in response to increased nutrient loading. This may enhance the production of pelagic (feeding on planktonic organisms) fish, while benthos (dwelling on or in bottom sediments) and demersal (dwelling at or near the bottom) fish production may start to decline owing to DO deficiency (Kurimoto and Kuramoto, 1992). With regard to demersal fish and shellfish (see Figure 3), reponses to increased nutrient loading (phosphorus loading in the case of Figure 3) are different according to species (Joh, 1991). Catches of mantis shrimp and flat fish decline in propotion to phophorus loadings which exceed 14 tonnes per day, while those of octopus, shrimp, and crab start to decline at smaller phophorus loadings (less than 5 tonnes per day). Although the exact mechanisms of such qualitative changes in the fishery catches has not yet been clarified, it should be noted that the commercially most valuable demersal species decline at a rate corresponding to the extent of eutrophication, and may be replaced by less commercially valuable small pelagic fish populations.

In fact, in the Seto Inland Sea, of which Osaka Bay is a part, fishery catches of higher-priced demersal species, such as red sea bream, kuruma prawn and octopuses, show a declining trend in the first and second phases (1963 to 1975) of the eutrophication process, while lower-priced pelagic and mesopelagic plankton feeders, such as sardine, anchovy and sand lance, rapidly increased during the same period (Tatara,1981). Although it is necessary to look at the combined effects of eutrophication and increased fishing efforts toward capturing higher-priced fish species, these above trends probably illustrate an alteration in catch composition due to the effects of eutrophication.

As another example of biological changes, in the innermost part of Tokyo Bay, most macrobenthic species disappear during the period when DO depletion is observed on the bottom during the summer, and azoic (lifeless) areas can often be found in late summer. Furota (1991) pointed out that these azoic or almost azoic bottom conditions (less than five species and total biomass of macrobenthos less than1 g wet weight per square meter) tend to be found under a DO concentration of less than 2 milligrams (mg) per liter on the bottom. This suggests that a 2 mg per liter DO concentration is a cutoff limit for survival of macrobenthic populations in the innermost part of Tokyo Bay. As a result of strict enforcement of laws controlling waste water since the 1970s, water quality in Tokyo Bay has gradually improved, and fauna in the bay, including commercially valuable species, have correspondingly increased to the increase in DO levels (Shimizu, 1988). However, according to a numerical model estimate of the DO balance in Tokyo Bay required to maintain the DO concentration above 2 mg per liter all year round, the present nutrient loading into the bay must be reduced by nearly 50 percent (Kuramoto and Nakata, 1991).

A striking example of the recovery of animal species that were on the verge of extinction is that of Dokai Bay located near the western entrance to the Seto Inland Sea (Yamada et al., 1991). This bay suffered from excesssive water pollution caused by industrial and chemical wastes during the first half of the centry. However after enforcement of wastewater laws in the 1970s, water quality improved, most animal species recovered. The commercial fisheries of kuruma prawns (Panaeus japonicus) which had been abondoned earlier were even restarted in 1983.

One of the most serious causes of deterioration in the quality of Japanese coastal waters is the loss of tidal flats and seaweed beds. Tidal flats and seaweed beds are localized zones of high biodiversity where pelagic and benthic ecosystems interact. Coastal engineering works such as reclamation projects and dredging are mainly responsibile for the loss of these areas.

The loss of tidal flats and seaweed beds, in addition to directly affecting biodiversity and bio-productivity, has exacerbated eutrophication problems because these areas play a significant role in the removal of nutrients and organic materials. Horie (1991) proposed that water and bottom quality can be improved by restoring the habitats (i.e., tidal flats and seaweed beds) of benthic animals.

Figure 4 illustrates the magnitude of the changes in the coastline of Tokyo Bay between 1950 and 1988 (Ishikawa et al.,1991). More than 80 percent of the coastline has been reclaimed, mainly for the industrial development, since the Second World War, and the remainder is still threatened by development. In addition to causing serious damage to the habitats of intertidal benthic species, Furota (1991) estimates that reclamation since the Second World War resulted in the loss of approximately 91,000 tonnes of macrobenthic biomass. In a similar example, Osaka Bay, which retains only 2.8 percent of its natural coastline, has witnessed a serious reduction in the shellfish production (Joh, 1991).

Parallel to the loss of tidal flats, seaweed beds, such as eelgrass (Zostera marina) beds, have also rapidly disappeared. According to the Nansei (formerly Naikai) Regional Fisheries Research Laboratory, approximately 53 percent of all the original eelgrass beds in the Seto Inland Sea were lost by 1965. Furthermore, half of the remainder disappeared between 1965 and 1971, and by 1971 eelgrass beds occupied only 2.1 percent of the total area shallower than 10 meters. Azuma (1981) warned almost 20 years ago that in areas where eelgrass beds were prominent, rapid simplification of the animal comunity occurred when such an area was reclaimed. He also pointed out that serious decline in the eelgrass beds could be accompanied by reduction in catches of small shrimp, crab, red sea bream and other species which depend on the eelgrass beds during their life cycle.

Coastal reef areas in the northern part of Japan have suffered from isoyake in recent decades. Isoyake is characterized by a replacement of sublittoral brown algae, such as Eisenia bicyclis, the most typical species producing marine forests along the Pacific coast of northern Japan, by less productive crustose coralline red algae. E. Bicyclis marine forests are known for their diverse animal communities. They serve as feeding habitat for commercially valuable marine species including sea urchins, and abalones and other reef fishes.

The cause of the isoyake phenomenon is as yet unknown. One hypothesis is overgrazing by sea urchins (Strongylocentrotus nudus). Other hypotheses include competition for substrate with other algae, hydrographic changes such as temperature changes which affect the physiological conditions, and water pollution. A project was started in 1997 by the Japan Fisheries Agency to investigate the isoyake phenomenon and its possible biological and ecological causes. Independent of the cause, there is pressing need to restore marine forest areas devastated by isoyake so as to enhance their functions as a nursery and habitat of living resources (Taniguchi, 1990; 1991).

1. Heavy metals: The loading of heavy metals such as Hg, Cd, and Pb into coastal waters began around 1900, slowly increased in the decades before the Second World War, rapidly increased during the period of economic recovery and boom growth after the war, and began to taper off beginning in the 1970s. Figure 5 shows vertical distributions of various heavy metals in the sediment of Tokyo Bay (Matsumoto, 1983). Heavy metal contamination peaked around 1970, corresponding to the peak loading from the land. The situation has improved in recent years; however, the concentration levels of these elements are above background values of deep sediment samples.

   

   Figure 5: Vertical distributions of heavy metals in the sediment collected from the central Tokyo Bay(from Matsumoto, 1983)

   
   

2. Oil: As compared to the period prior to 1975, there have only been a few incidents of major oil spills. This is probably due to the enforcement of legal regulations. Figure 6 shows the annual change in the total weight of tar balls recovered at seashore monitoring stations by the Maritime Safety Agency of Japan (Seko, 1994). It is evident that the tar ball weight significantly declined in early 1980s. The same trend is detected in the amount of drifting tar balls at the sea surface as well. Despite these trends, the recent oil spill from the Russian tanker Nakhodka in the Sea of Japan in January 1997 revealed the lack of a systematic response strategy for the oil spills. It is urgent that a predictive and operational model be developed for preventing environmental damage caused by oil spills.

   

   Figure 6: Year to year changes in the weight of tar balls collected from the sea shores (solid line) and the surface water around Japan (broken line) (from Seko, 1994)

   Oil slicks in the open ocean have also been monitored by the Maritime Safety Agency, using voluntary ships. Figure 7 illustrates the horizontal distribution of the surface oil slicks detected between 1975 and 1988 (Seko, 1994). This suggests that oil contamination still needs continual monitoring and preventive measures on an international basis.

   

   Figure 7: Distribution of drifting oil slicks detected by ships of opportunity during 1975-1988 (from Seko, 1994)

   
   

3. Organic contaminants: Organochlorine compounds such as PCB (polychlolinated biphenyl), DDT (an organochlorine insecticide) and HCH (hexachlorocyclohexane) are known to be highly toxic and have a strong tendency to bioaccumulate, particularly in higher trophic levels of a marine food web. This is why the distribution and the effects of these substances on marine ecosystems have been of great concern in recent years. As far as the marine environment is concerned, these substances (which tend to be used on land surfaces) find their way to the sea and end up being accumulated in the sediment and in organisms which live in coastal waters (Tanabe and Tatsukawa, 1981). Even after the production of these substances was prohibited, their concentrations of PCBs, etc. in the marine environment have only diminished very slowly.

   In the open ocean, organochlorine contamination was pronounced in the middle latitudes in the Northern Hemisphere until early 1980s. However, recent reports have pointed out that such contamination has become more severe in the tropical and subtropical regions (Tanabe, 1995). This again suggests that in order to improve the situation international cooperation with developing countries is essential.

   In addition to organochlorine contamination, there are newly emerging problems with other toxic chemicals such as TBTs (tributyltin-compounds), PAHs (polycyclic aromatic hydrocarbons), and dioxins. The Japan Environment Agency is engaged in continual monitoring of these contaminants since the 1980s, particularly focusing on TBTs and dioxins, both of which are noted as an "endocrine disrupting substance". Preliminary results indicated that the contamination by these toxic chemicals has expanded in territory (Tanabe, 1995).

4. Plastic wastes: Recent investigations made by the Japan Fisheries Agency revealed that about 60 percent of the drifting debris in the North Pacific were made up of plastic wastes. Plastic wastes in Tokyo Bay made up more than 80 percent of the total debris collected with a demersal seine. The plastic wastes were mainly composed of various daily use articles, and rope and fishlines used by the fishing industry. It has been suggested that the plastic wastes injure marine animals (when swallowed or when animals become tangled with the debris).

Considering the rapidly increasing human population, it is an urgent need to enhance global food production in a sustainable manner is a high priority. Given the problems with expanding production on land, many people are looking to the oceans, especially the coastal seas, as a food supplier in the future.

As is indicated by the data presented in this paper, the present situation in Japanese coastal waters does not provide an optimistic view of the possibility of the coastal waters being such a resource in the future. Most areas are suffering from the severe degradation of water quality and rapid losses of the coastal habitat of fisheries resources. Past human exploitation of coastal resources with less concern for the ecological cost is mainly responsible for these changes. During the period of high economic growth in the 1960s and 1970s, the Japanese coastal environment, particularly around urbanized areas, was severely damaged. In other words, vast economic growth was accomplished at the cost of the ecological degradation of coastal waters. Times have changed, and some attempts have been made in recent years to improve the ecological quality of the coasstal waters. These efforts include construction of artificial habitat such as reef placement, marine afforestation, and upwelling enhancement (Nakata, 1995). Another effort is development of technology for pumping up the deep, clean, and nutrient-rich water. A pilot plant for utilizing the deep water for aquaculture production is now operating in Kochi, on the southern Pacific coast of Japan. Knowledge about the impact of ecosystem enhancement measures and artificial ecosystem creation is still very fragmentary. More effort needs to be made to collect high-quality quantitative data to further advance habitat technology.

Among various future tasks related to the habitat technology, priority should be given to the restoration and creation of coastal nurseries such as tidal flats and seaweed beds. These areas play a very important role in the reproductive potential of most valuable fisheries resources. In this respect, it is imperative to investigate the ecological features of the natural system before designing artificial habitats. In fact, an intensive survey on the nutrient (nitrogen, in this case) budget of a tidal flat has recently revealed a new aspect of the ecological function of the tidal flat ecosystem. As is shown in Figure 8, a tidal flat consists of both plankton and benthic ecosystems. This complicated feature diversifies the food web system on the tidal flat and probably enables the nutrients to reside long enough to be converted into particulated material through biological production. Some of the nutrients are thereafter removed by fishing of marine species such as shellfish and seaweed. The effective trapping and removal of the nutrients contributes to maintaining high productivity on the tidal flat. Improved knowledge of the mechanism of this effective material transfer in the natural system, will help guide the technological development of ecological manipulation of the production system in coastal waters. .

Furthermore, the potential capability of artificial seaweed beds to remove the nutrients from Tokyo Bay has recently been estimated (Yamaguchi, 1993). Table 2 shows that the rates of nitrogen removal by large brown algae, such as arame (E. bicyclis), amount to more than 20 percent of the total nitrogen load from the land when such artificial seaweed beds are constructed to the maximum area extent possible in the bay. It should be noted, however, that the large brown algae will not be able to grow and survive in Tokyo Bay if water quality remains high in turbidity and pollutant concentrations. This indicates that the first priority for making full use of the ecological functions of the algae by artificial seaweed beds construction is to reduce the amounts of nutrients and pollutants in the bay to below a certain critical level. This suggestings that production enhancement can only be achieved in tandem with the restoration of the entire ecological system.

Another important task is to monitor ecologial changes on a long-term basis. Figure 9 illustrates a recent example of the long-term monitoring of the coastal fauna of benthic animals near Kure-city in the Seto Inland Sea (Yuasa, 1995). The numbers of species observed at six monitoring stations show rapid decline between 1960 and 1990. The inner stations started to decline earlier than outer ones. The number of species has not yet been recovered even after the Seto Inland Sea Conservation Law were enacted in 1973 and enforced reduction in total nutrient loads into the sea in addition to promoting natural seacoast conservation. Unfortunately, except for this study, there have been very few time-series datasets obtained on the ecological response to environmental change in coastal waters in Japan. It is therefore urgent to establish a well-designed and operational monitoring network in the coastal waters around Japan.

With respect to the problems caused by hypereutrophication and chemical contaminants, priority should be given to legal regulation based on a water quality standard. In June 1993, the Central Pollution Council set nitrogen and phosphate standards for coastal waters in order to improve the hypereutrophicated condition of urbanized bays (Table 3). Based on hydrographic characteristics and present water quality, four coastal water categories were established, and the standards for the nitrogen and phosphate were applied to each category. The environmental standard for toxic chemicals was also revised in 1993. Twenty-five (25) elements, including organochlorine compounds, which have emerged as environmental pollutants since the standard was first established in 1970, were newly added. .

In addition, following the enactment of the Basic Environment Law in November 1993, a national Environmental Impact Assessment Law was also enacted after several years of effort. The objective of the Environmental Impact Assessment Law is to ensure the adequate consideration of environmental preservation in the implementation of projects. This law will enter into force in June 1999. Basic technical guidelines are now being prepared for the assessment process. An important task related to this movement is to establish the appropriate methods for the rational assessment of all possible risks to the marine coastal environment. A practical method for assessing the human impact on coastal ecological systems related to the fisheries production has recently been proposed (Nakata and Hirano, 1989). In addition, ecosystem modeling has not yet been incorporated as a practical tool for this assessment, although there are high expectations that it will become a significant aid to the prediction of habitat changes and proper management of living resources (Nakata, 1991). Again, it is necessary to include long- term monitoring of ecological responses to the environment change as an essential part of any environmental impact assessment program.

The Basic Environment Plan, established by the Japanese Government in December 1994, outlines the overall and long-term policies through the middle of the 21st century of the government in environmental conservation. This plan sets the following four long-term objectives: to establish a socioeconomic system fostering environmentally sound cycling of substances, to ensure harmonious coexistence between nature and human beings, to build a society where all parties participate in environmental conservation activities, and to promote international environmental efforts. Needless to say, these objectives apply to conservation and restoration of marine environment, as well as other areas of environmental concern.

Current socioeconomic systems dominated by mass production, mass consumption and mas disposal must be first reexamined. Increasing disposal needs a new disposal cites in the sea and would promote reclamation of the coastal nurseries and habitats. The gravitation of population toward cities would have accelerated the speed of disposal increase. It is necessary to develop a method for evaluating proper economic values of environmental damages and costs in comparison with the socioeconomic benefit of the projects such as the reclamation.

Kurihara (1988) proposed an ideal design for the ecological manipulation of the coastal environment (Fig. 10), in which the removal of organic materials, such as that contained in fishery and aquaculture products, is balanced by the external input from the land to the coastal seas. Artificial habitats would be well organized and deployed in the system in combination with existing natural ecosystems and fishery activities. In order to realize such an ideal system, it is first necessary to undertake detailed investigations on the circulation and budget of materials such as nutrients and dissolved oxygen (see Fig.8). There have, however, been very few quantitative case studies.

The most productive areas in coastal waters are often found in the zone between land and sea, i.e. tidal flats, estuaries, surf zones, etc. Therefore, mutual cooperation between researchers working on land-related issues and sea-related issues is absolutely essential. In fact, as has been pointed out in relation to the seaweed bed construction in Tokyo Bay, cutback of material loading from the land into the bay is a prerequisite for utilizing the ecological functions of the seaweed bed to intake and remove excessive nutrients in the bay.

However, current administrative systems for environmental management have so far neglected such a continuity of the environmental system, resulting in failure of environmental conservation and restoration.

Related to this, fishermen engaged in coastal fishery and aquaculture activities have begun to take actions to preserve and restore forests in watersheds neighboring their fishing grounds. Intact forests will contribute to maintaining the quantity and quality of the water discharged into the sea. This in turn may result in production enhancement of coastal fishing grounds. In fact, there is a history of forest reserves along the seashore (so-called Uotsuki-rin in Japanese) to preserve good fishing grounds. However, the area has been reduced from 54,000 ha to 28,000 ha during the last four decades. The collapse of traditional communities linking forestry and coastal fishery owing to the modernization of society and industry has accelerated the reduction in the forest reserves. Under these circumstances, fishermen have realized that an integrated approach linking the sea to the land and a long-term perspective are necessary. The coastal fisheries catch near the Cape Erimo, in the southeastern part of Hokkaido Island, actually began to increase about 20 years after the establishment of a seashore forest. Such social activities, including education and training, are strongly recommended in order to accomplished sustainable development of coastal regions.

Considerable knowledge and experience have been accumulated on the environmental change and its impacts on the marine coastal ecosystem in Japan. Japanese knowledge and experience should be especially useful to newly developing countries which are faced with great ecological losses caused by economic growth just as the Japanese experienced during 1960s and 1970s. Utilization of this knowledge and experience may possibly contribute to preventing irreversible ecosystem damage in the future. The promotion of an international cooperative program in this aspect is therefore promising. In particular, there is serious shortage of funds, technical know-how and experts to restore the environmental problems in the developing countries. For example, a project-type technical support, including dispatch of experts and acceptance of trainees, has been conducted by JICA (Japan International Cooperation Agency), etc. In addition, some of local governments have also made similar effort to support the developing countries in the environmental problems.

Among regional seas around Japan, the Sea of Japan should have the priority of the international cooperative approach. This sea is surrounded by Russia, North Korea and South Korea, and has been threatend with environmental pollution due to land-based discharges of heavy metals, etc., and illegitimate radioactive wastes dumped by Russia. Further, about half of the nuclear power plants of Japan are located along the coast of this sea. In addition, this sea has deep basin relative to the surface area and shallow sill at the entrances/exits, resulting in small water exchange and potential danger of accumulation of various pollutants in the deep basin. Therefore cooperative monitoring and pollution control with the neighboring countries will be indispensable to environmental conservation of the Sea of Japan.

Finally, in order to achieve these goals, it is absolutely essential to realize that human beings are members of the biosphere of the earth, and share its limited energy and resources with other living beings. In this respect, Takahashi (1992) points out that an evolutionary switch in socio-cultural thinking is required in the future. He postulates a switch from rule by modern technocrats, who base their choices on advanced high technologies, to rule by a new generation of "ecocrats". These ecocrats prefer to live in natural ecosystems without causing adverse impacts, but they still desire to utilize the productivity and ecological functions of the natural system to the maximum possible extent. The technology and the social system based on an understanding of ecosystems will forward the goal of realizing sustainable exploitation of the blessings of marine environment.

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