Supply Chain-Based Coral Conservation: The Case of Mozuku Seaweed Farming in Onna Village, Okinawa

In particular, the naturally distributing red soil run-off in the northern part of mainland Okinawa Island often flows directly into the ocean. That is because it is often affected by natural environmental factors such as heavy rain squalls, the steep slopes and short rivers typical of island regions, and human factors such as agricultural activities and development. The red soil run-off accumulates in lagoons with pool-like topography and has several negative effects, such as reducing photosynthesis of seaweeds and seagrasses due to turbidity and inhibiting zoospore/coral planula settlement [53,54].

Conflicts between developers and the OVFC led fishermen to protest marches by boats in 1986. As a result of many years of protests and consultations, the OVFC now plays a central role in managing sea surface use [55]. For example, rules have been established to prevent conflicts over the use of fishing grounds in Onna Village’s waters. It is required to consult the OVFC before starting out any marine leisure businesses in this area, and OVFC member vessels must be used for diving operations. Additionally, the Onna Village Environmental Conservation Ordinance stipulates that resort wastewater must undergo advanced treatment. In Onna village, when large-scale development is undertaken, countermeasures are required to be discussed at the Red Soil Runoff Prevention Council, which consists of the municipality, the ward, the OVFC, construction companies, and others.

Figure 7 shows the Suspended Particles in Sea Sediment (SPSS) values of 20 points in the estuary of Onna Village measured by the OVFC producers between 2010 and 2015. SPSS is a convenient measuring method of monitoring soil run-off and was developed in 1985 [56]. The sedimentation monitoring method is widely accepted in Okinawa due to its fast measuring times, mobile and simple operation, and lack of requirement for special equipment [57]. Boxes, central lines, interval lines above and below each box, and circles indicate 25th–75th quartiles, median, max, and min distribution values, and outlier values, respectively. The number below each point’s initial letters indicates the pollution level, and a rank of six or higher (50 kg/m³) is considered to be clearly contaminated by anthropogenic red soil or other run-off.

Measured red soil values in Onna Village are generally lower than in other areas in the northern region of Okinama main island because the entire region has taken preventive measures and established a system to monitor red soil run-off, and fishermen themselves have monitored and pointed out run-off conditions based on scientific evidence (Figure 7). However, further improvements are required because facilities to prevent red soil run-off are not functioning and run-off from agricultural lands, which are not covered by the monitoring system, is observed. Farmers in Onna Village are aging more rapidly than fishermen, and the labor and expense of implementing red soil run-off countermeasures pose a significant challenge. Currently, Onna Village Agro-Environment Coordinator Mr. Ryo Kirino is working tirelessly to establish sustainable measures, both in terms of finances and manpower. For example, the Honey & Coral Project transforms fallow land into flower gardens, generating both honey and revenue while reducing red soil run-off [58].

OVFC producers believe that a healthy coral reef ecosystem, including corals, seagrass beds, and sand and gravel bottoms, is essential for Mozuku production. Therefore, since the late 1990s, they have been dedicated to nurturing healthy and diverse coral reefs in Onna Village. They focus on caring for coral parents and promoting their spawning [59]. Sea surface temperatures in the seas around Japan have exhibited decadal-scale fluctuations, and the average rate of sea surface temperature increase is +1.24 °C per 100 years, which is higher than the global rate of sea surface temperature increase (+0.60 °C per 100 years) [57]. Recent climate change, represented by frequent El Niño and La Niña events, has significantly affected the stable production of seaweed aquaculture in the OVFC. Production of N. decipiens, which is at the southern limit of its natural distribution, is particularly susceptible to the effects of climate change. While the OVFC has been involved in selecting and breeding mother algae that are tolerant to high temperatures, given recent climate changes, there is a need to develop strong Mozuku varieties that can thrive within a wider range of suitable water temperatures. The OVFC continuously engages in selecting and breeding strains capable of withstanding environmental exposure each year to ensure stable production. In parallel with this effort, the OVFC was actively collaborating with Igeta Takeuchi Co., Ltd. to assess our products’ quality.

As mentioned above, OVFC producers have worked to preserve and restore coral reefs to ensure the stable production of Mozuku. Measures taken to reduce red soil run-off not only prevent the reduction in Mozuku quality and quantity but also protect seagrass beds since Mozuku cultivators have continued to use seagrass beds as an important nursery. Seagrasses are known to be extremely important for maintaining ecosystems, but their area is decreasing dramatically around the world [60]. Seagrasses are disappearing at a rate of 110 km²/year and nearly 30% of what we had in 1879 has disappeared [61]. Conservation monitoring is conducted around the world; however, it is often carried out at a scale that is too coarse or too infrequent to detect changes effectively [62]. This highlights the importance of conserving and monitoring the seagrass bed by the OVFC as their Mozuku nursery ground and accumulating data daily. Although it has been reported that the area of seagrass beds is decreasing due to the influx of red soil into the ocean in Okinawa [63], at least 189.94 ha of healthy eelgrass beds remain in Onna Village [64]. According to Onna Village, 11 species (three families) of seagrass inhabit the lagoon in Onna [65].

Mozuku cultivated by the OVFC is harvested, so the amount of blue carbon stored in the ocean is not large, but it is believed to exhibit a certain level of carbon sequestration during the cultivation period. In addition, since seagrass beds are used in Mozuku farms, healthy seagrass beds are essential and it will be possible to assess the blue carbon effect of seagrass beds to some extent. However, there are few studies on tropical and subtropical seagrasses, and the details are unknown. In recent years, a report on the carbon dioxide fixation ability of C. okamuranus was published [60] describing that it can fix 3.6 g C m⁻² (0.034 g C m⁻² d⁻¹). The whole picture of the blue carbon effect for C. okamuranus is still unknown, and future research including N. decipiens is expected.

In this sense, quantitative evaluation of environmental, economic, and social benefits through data accumulation, which is one of the principles of restorative aquaculture [24,28], is extremely important. Thus, the OVFC’s efforts with related organizations to promote seaweed farming and coral reef nurturing activities in response to climate change can be considered pioneering, as producers are implementing climate change mitigation and adaptation measures while collecting data including water temperature, sea surface height anomalies, events related to El Niño and La Niña, water quality, and crown-of-thorns starfish population density.

One of the research questions in this paper is, “What quality assurance technique is necessary to continue restorative aquaculture as a market-based solution over the long term?”. As explained in Section 3.3, the basis of long-term relationships is a shared definition of quality between producers and processing companies, as well as a mutual understanding of the constraints imposed on each by the natural environment and food processing sites. From the perspective of producers’ livelihoods, this close relationship in the supply chain is also reflected in the price of Mozuku. When the unit price of Mozuku was JPY 83 or 84 per kilogram around 2008 and 2009 (Table 2), the unit price at the OVFC was JPY 120. Figure 8 shows unit prices for Okinawa Prefecture as a whole and the OVFC before and after 2009. As mentioned above, although the OVFC produces more N. decipiens than other fishermen’s cooperatives, this comparison focuses on C. okamuranus, because producing C. okamuranus is the mainstream in the prefecture and the actual price trend is also greatly influenced by C. okamuranus. It should be noted that the unit price for Okinawa as a whole includes N. decipiens, but judging from the total amount, the unit price trend is largely influenced by C. okamuranus. The unit price at the OVFC has almost always been higher than Okinawa’s average and it never goes below JPY 120. Most of all, unlike other fishery cooperatives, the OVFC never has to adjust production or stop harvesting due to overstock or extreme price drops.

To address the second research question, “What social platforms and communication channels are available to stakeholders to sustain restorative aquaculture in the long term?”, it can be stated that the OVFC mainly markets its Mozuku to consumer cooperatives throughout Japan. Co-ops in Japan have both stores and home delivery services, but in the case of home delivery, customers place orders by looking at a weekly order catalog. The amount of information in the catalog helps inform consumers about the activities behind the Mozuku produced by the OVFC, such as coral conservation and soil run-off prevention. The OVFC started planting multiplied corals in 1998, and a few consumer co-ops joined this activity in 2007. From then until the end of 2022, 43,646 corals were planted (Figure 9). The Mozuku Fund (Mozuku Kikin) scheme was established in 2009 to support this activity as a whole supply chain. One package of seasoned Mozuku is sold, and about one yen (almost equivalent to one cent) is returned to the OVFC. Since then, consumer co-ops from all over Japan have participated one after another. The number of consumer household members of these co-ops is about 6 million in total. There were 6.1 million packages of Mozuku products sold through this scheme in 2022, and 34,160 corals were planted through the support of consumer cooperatives over the years. Consumer cooperatives participating in this program also provide their members opportunities to visit production areas. Producers are also offered opportunities to ride together in delivery trucks (Figure 10), allowing consumers and producers to interact with each other on various occasions. This interactive distribution is also a feature of the consumer cooperatives participating in the Mozuku Fund. This project involves consumer participation across Japan, all contributing to the development of Onna Village’s Satoumi [47]. As a result of these efforts, the coral cover in the coastal area of Onna Village has exceeded 50%, making it an exemplary model of Satoumi creation for coral reefs in the sub-tropical regions.

Market-based solutions [24] mean that commercial restorative aquaculture can offer environmental solutions for ocean health. Reflecting on the OVFC case, we have concluded that the entire supply chain needs to be involved in solving both the environmental and socio-economic issues of the producers and production area. This can be achieved by developing and selling products that highlight the locality. As for aquaculture techniques that improve the quality, especially for C. okamuranus, other production areas will eventually catch up, so it will be difficult for OVFC’s producers alone to carry out Mozuku aquaculture as a form of restorative aquaculture while reaping economic benefits. In the case of the Onna Village Fisheries Cooperative, one way to solve this problem is to carry out Satoumi conservation, which involves working with each distribution stakeholder for many years.

Japanese consumer cooperatives have become the world’s largest organizations in terms of membership and turnover, and they are characterized by strong member participation [66]. They established a distinct business model centered around a weekly catalog and order system, focusing on home delivery and strongly emphasizing social and environmental activism. The difference between large-scale retail stores and consumer co-ops is that because consumer co-ops are membership-based, the characteristics of products are communicated to a specific number of people rather than to an unspecified number of people. Through the Mozuku Fund system, each distribution stage is seamless, sharing issues concerning the ocean in Onna Village and supporting the conservation of coral in Onna Village’s ocean. A two-way exchange has been established in which the entire distribution chain, including consumers, resolves environmental issues in production areas. In 2017, the government of Onna Village joined this initiative as a partner, which means that the private sector’s coral conservation centered on algae farming has been incorporated into official government policy.

The OVFC’s Mozuku case discussed in this paper falls into type 3 of the supply chain approach [45], which seeks to be spatially extended, meaning that the value and meaningful information about the place of production and the people involved in producing the food are transmitted to consumers who are not located in the region where the food is produced. As Marsden et al. [45] adds, “Notable here are the additional identifiers which link price with quality criteria and the construction of quality. A common characteristic, however, is the emphasis on the type of relationship between the producer and the consumer in these supply chains and the role of this relationship in constructing value and meaning rather than solely the type of product itself” (p. 425). The relationship between producers and consumers characterizes Japan’s consumer co-op system, and consumers are not only interested in simply consuming Mozuku but also have a good understanding of its environmental significance and climate challenges.

In recent years, the further use of blue foods has been advocated [4]. Seaweed is currently underused, has the potential for increased production, and is gaining attention due to its low environmental impact. Restorative aquaculture occurs when aquaculture provides direct ecological benefits, potentially generating net-positive environmental outcomes [24]. This is very similar to the Satoumi concept [47,48], which claims that ocean biodiversity increases with appropriate human intervention. In this paper, we first explored what quality assurance technique is necessary to continue restorative aquaculture as a market-based solution over the long term. The OVFC has been working on coral conservation from an early stage based on this Satoumi concept, focusing on the interactions between Mozuku growth and coral health. In addition, they are devoted to pursuing the quality of Mozuku as food, and at the same time, they continue to select strains that can cope with climate changes, such as high water temperatures. It is not easy to find suitable strains for processing that have good taste and texture and are adaptable to climate change. In addition to climate change, the OVFC has also responded to environmental changes and impacts from the land area, such as soil run-off caused by heavy rainfalls and agricultural activities, as the impact of severe weather on algae aquaculture will increase [18].

“Alternative Food Networks” (AFNs) are a practice and an academic body of literature concerning the emergence of alternative food practices as a reaction against industrial, standardized, globalized, and unethical food systems [67,68]. Represented by practices such as community-supported agriculture, fair trade, and farmers’ markets, AFNs explore a new form of food provisioning connecting rural producers (production area) and urban consumers [69]. The term localization is often associated with AFNs and is discussed in two senses; one focuses on the close geographical proximity to where food is produced, represented by direct “face-to-face relations”. In the broader sense, food localization is defined as attempts of practices to enhance transparency in production and distribution channels and to connect the identities of the production area and producers to products while communicating the unique values of the area to the wider world [70]. It does not make sense to define an AFN over distance in this context [69]. This type of AFN has also been discussed and centered on social “embeddedness” linking food to place. However, this analysis mainly focused on consumer–producer relationships, and little attention was paid to the mechanism within AFNs to redistribute and capture value [68,71].

This leads to our second research question: “What social platforms and communication channels are available to stakeholders to maintain restorative aquaculture in the long run (and over the distance)?”. Laginová et al. [69] points out that AFN models are often built upon organizational innovations, which are often associated with introducing information and communication mechanisms.

Consumer cooperatives involved in the supply chain of the OVFC’s Mozuku are membership-based and offer home delivery, and themselves have been a form of AFN with a strong focus on social and environmental activism. In this regard, the consumer cooperatives in this case study are the type of AFN associated with the broader sense of localization and function as a social platform enabling stakeholders to maintain environmentally/economically sustainable Mozuku production. More specifically, to redistribute and capture value in the Mozuku distribution, the Mozuku Fund works as a communication channel in this case. The Mozuku Fund labels (showing an illustration of coral and fish) on each package of Mozuku products capture values other than economic value and visually articulate the redistribution of economic gain to restorative aquaculture practices. Notably, consumer cooperatives can have a large number of members and generate social impact. In this type of AFN, irrespective of geographical distance, trust born through proximity, such as face-to-face relations, is supplemented and substituted by the scheme proving “authentication”, such as certifications and labels [72].

A study of the carbon dioxide fixation ability of C. okamuranus has been published [58]; however, the whole picture of the blue carbon effect for C. okamuranus is still unknown, and future research including N. decipiens is expected. Such research could expand the possibilities of the role of locally appropriate commercial algae farming as a climate change mitigation measure and the importance of market-based solutions worldwide.