Figure 1.1 Map of Matsushima Bay (Miyagi Prefectural Government 2015)
(Map Data of Matsushima Bay: Google 2017, ZENRIN)
On March 11, 2011, the Great East Japan earthquake and resultant tsunami caused severe damage in Japan. Large areas of the Pacific coast surrounding Matsushima Bay in northeastern Japan sank by approximately 80 cm (GSI 2011). This triggered a huge landslide and caused rocky cliffs of many uninhabited islands to collapse (Hasegawa et al. 2011). The huge tsunami also destroyed entire infrastructures such as sewage facilities, piers and fishing gear. As a consequence, Norovirus contamination became frequent along the northern Pacific coast. Nearly 20,000 people along the coast of Miyagi Prefecture were victims of the tsunami (MPG 2015), and 8,106 inhabitants from the Matsushima area moved to other cities (MAFF 2015). Geographic and physical changes have altered ecological processes in the bay, with severe consequences for fisheries and aquaculture. Although the relationship between the earthquake and the changing oceanographic conditions have not been well investigated, the annual temperature fluctuation increased in 2012 (Miyagi Fisheries Technology Center 2016). Consequently, experience and many previously used farming theories can no longer be relied upon to predict the biological cycles – for example, the spawning period, larval distribution and settlement of oysters.
Vast restoration efforts followed, and the local industries have restarted, including aquaculture. However, further attention and continued support from the national and/or prefectural government are needed. It is important to analyze the present situation and evaluate the resilience of industries, which requires an interdisciplinary effort. In this chapter, I adopt the I-ADApT framework (Bundy et al. 2016) to evaluate the resilience of oyster farming in Matsushima Bay, describing the natural system of Matsushima Bay and the status of oyster farming prior to the tsunami, the damage caused by the disaster and the consequent Norovirus pollution problem for this industry. The problems and challenges are considered by comparing former and present conditions in the natural environment, social status, political governance, marketing and scientific research.
Matsushima Bay is located in the Miyagi Prefecture, Tohoku Region, northeastern Japan, and covers an area of 35.3 km2 (Fig 1.1). The mouth of the bay is 1.7 km wide in the southeast, 5 km in the south and 10 km in the west (Ichinomiya and Taniguchi 1982). The surrounding area has a combined population of 128,875 (Statistics Bureau 2011), including the inhabitants of the four islands at the bay’s entrance. The bay is partially closed by the islands, but there is daily tidal exchange via the six channels that they form. Three offshore currents seasonally replace the water in the bay (the cool Oyashio Current in winter, the warm Kuroshio Current in summer and the warm Tsugaru Current in spring). The tidal range is 1.6 m. The seabed is composed mostly of muddy silt (median grain diameter range 0.075 mm–0.005 mm) with flat sandy (median grain diameter range 2.0 mm–0.075 mm) areas near the mouth of the bay and at the eastern edge where there are dense beds of seagrass (Zostera spp.).
The average depth of the bay is 4 m (Ichinomiya and Taniguchi 1982), and a channel has been dredged to accommodate large-vessel traffic. Because the bay is shallow, the temperature correlates closely to the air temperature and ranges from 4°C (February) to 26°C (August) (Miyagi Fisheries Technology Center 2016). Summer rainfall causes salinity to fluctuate from 33 psu to 25 psu. The pH of the water in the bay varies from 7.7 to 8.4 (Statistics Bureau 2011). There is no river system feeding into the bay, and only the small Takagi River (total length 7.7 km) and two canals influence the bay’s nutrient supply. Nutrients, such as dissolved inorganic nitrogen (DIN), phosphate phosphorus (PO4-P) and dissolved silicate (DSi), are gradually supplied in early autumn by rainfall and the decomposition of the seagrass. These nutrients are utilized by the extensively cultivated seaweed (Porphyra) in the bay during winter. In the 1970s, eutrophication was an issue. However, the ecological condition improved with the establishment of the sewage treatment facility in the area.
Figure 1.1 Map of Matsushima Bay (Miyagi Prefectural Government 2015)
(Map Data of Matsushima Bay: Google 2017, ZENRIN)
Prior to the Great East Japan earthquake, annual oyster production in Miyagi Prefecture had steadily risen from around 20,000 tons in the 1970s to 30,000 tons by the 2000s, amounting to approximately 13.6 percent of the Japanese production in 2008 (Figure 1.2). In Matsushima Bay, oyster farming is a major activity, and annual oyster production prior to the tsunami (2008) was 577 tons (shucked, equal to 5,766 tons with shell, Table 1.1). Matsushima Bay also played an important role in the supply of seed oysters for oyster farming country wide and was the second largest producer (up to 30 percent of the oyster seeds were produced in Miyagi) after the Ishinomaki Bay area (Tanabe 2012). In the rocky intertidal zone of Matsushima Bay, farmed brood stocks were supplemented with wild oyster larvae. Outbreaks of paralytic shellfish poisoning, which is caused by the harmful planktonic algae (Alexandrium tamarense, A. catenella) occurs frequently in spring. The Miyagi Prefecture Fisheries Technology Institute monitors the distribution of harmful algae along the coast. If they are observed in any of the 11 oyster harvesting zone divisions along coastal areas (Figure 1.3), oyster trading in the detected zone is suspended until harmful algae are not detected for at least two weeks. The Norovirus, which also causes food poisoning, was detected in oysters in the 1980s (Maekawa et al. 2007) and has become an increasingly important issue since 2008.
Statistic base: Joint marketing result of the Miyagi Fisheries Cooperatives Yearly production: Summed from September to May next year (oyster season)
The Fisheries Agency of the Ministry of Agriculture, Forestry and Fisheries (MAFF) has oversight of aquaculture and fisheries activities in Japan. The MAFF directs the prefectural governor to maintain sustainable use of the coastal zone, and the Miyagi prefectural governor gives the rights to the Fisheries Cooperative for proper management. The Miyagi Fisheries Cooperative in the Miyagi Prefecture has 28 branches (Figure 1.4) representing 10,069 fishers, 299 officer members and 21 directors. In 2007 there were 31 independent coastal Fisheries Cooperatives in the Miyagi Prefecture. These have since been consolidated into the Miyagi Fisheries Cooperative to reduce personnel costs. The Fisheries Coordinating Committee is subsidized by the Miyagi prefectural government (consisting of 15 elected members, including fishermen and a few academic experts nominated among fisheries, including the author of this chapter, company representatives and the prefectural administrator). Its basic role is to coordinate boat fishing and aquaculture in the coastal area of the prefecture.
Figure 1.3 Oyster harvesting zone division in Miyagi Prefecture
Source: Miyagi Prefectural Government Home Page
www.pref.miyagi.jp/uploaded/attachment/69094.pdf
(Google Map 2017, Zenrin)
Figure 1.4 Fisheries management system in Miyagi Prefecture
Reorganized from the organization chart Miyagi Fisheries Cooperativewww.jf-miyagi.com/pdf/kikouzu.pdf
Matsushima Bay oyster farmers (116 households in 2014) belong to four branches of the Fisheries Cooperative (Matsushima, 83; East Urato, 6; Urato, 19; and Shiogama, 8) (Table 1.2). Farming rights are usually transmitted from generation to generation. Because oyster farming does not provide sufficient annual income and involves heavy labor, there has been a lack of successors to retiring farmers in recent years. Many farmers ceased operations after the tsunami, leaving many unused grounds after the equipment and biomass were removed, thus resulting in an increase in primary production. In each prefecture, the governors have authority over aquaculture and grant fishing rights for oyster farming, in consultation with the Fisheries Coordinating Committees, every five years. The head of each Fisheries Cooperative branch can recommend candidates be granted a farming right if they have been engaged in fisheries for more than 90 days a year and have enough experience.
In Japan, the development of the raft culture system of oyster farming in the early 1970s contributed to a dramatic increase in production, which triggered an increase in the domestic demand for oysters. This in turn encouraged the development of an integrated oyster industry, including farming, processing and distribution. Fisheries Cooperatives played an important role between farmers and buyers (Lou and Ono 2001). They set size standards, starting dates for sales and treatment methods to ensure health standards so most end consumers can obtain oysters of a guaranteed quality. The Fisheries Cooperatives also negotiate large volumes of sales with retailers and fix the price of oysters every day. The role played by the Fisheries Cooperatives in negotiations had been greatly appreciated by farmers before the 1990s due to the trustful relationship. Oyster farmers were exempt from most of the negotiation efforts and respected the efforts of Fisheries Cooperatives to make enough profit for them at this earlier period.
This division of labor continued until the development of mass sales of oysters in supermarkets throughout Japan since the late 1990s. Over the past three decades, the bargaining power has gradually shifted from the Fisheries Cooperatives to the supermarket buyers. This appears to be due to a difference in approaching consumers. The supermarket buyers understand the consumers’ demand well and transmit consumer preferences to their suppliers. Accumulated know-how and experience of such buyers provided them a bargaining advantage. Often, buyers appreciate the current balance between supply and demand better than producers and lead the market price. On the other hand, the Fisheries Cooperatives and the oyster farmers are not powerful enough to impose their own conditions and often end up accepting the buyer’s price. These relationships have remained the same for the last 20 years, and the annual income of oyster farmers remains low. Data on earnings from a survey conducted by the research committee for Fisheries village activation in the Tohoku region in 2010 (Figure 1.1) reveal that the average annual revenue of an oyster farmer in Matsushima Bay was 3,127,000 yen (US$28,427) and its gross margin (i.e. the difference between revenue and cost) was 1,498,000 yen (US$13,618). Prior to the crisis, the total average turnover in 2008 was 5,337,000 yen (US$48,518) in Miyagi, and 38,162,000 yen (US$346,927) in Hiroshima (Table 1.3). Annual turnover in 1990 exceeded more than 6,000,000 yen (US$54,545).
The tsunami destroyed the fisheries infrastructure in Miyagi Prefecture. A total of 12,023 fishing vessels, 213 fishing ports, 577 cooperative shucking facilities, 67,158 farming rafts plus longlines and 1,609 aquaculture materials were destroyed. The loss of farming facilities was worth 7.63 billion yen (US$69.40 million) and biomass valued at 5.09 billion yen (US$46.30 million) (MPG 2012). The land in the Oshika peninsula and surrounding areas submerged by about 1 meter (GSI 2011), causing piers to sink and resulting in a tremendous amount of debris. Fisheries workers also had to worry about radioactive contamination. Chemical oxygen demand (COD) and coliform bacteria levels increased in May 2011 to 5.1 and 46,000, respectively, near the effluent discharge of the damaged sewage treatment facility. After six months the figures had returned to previous levels of 3.2 and 1,500, respectively (Fukuchi et al. 2012). The total cost of the sewage treatment damages in Miyagi Prefecture was over 213.3 billion yen (US$2.11 billion) (MLIT 2011). The emergency national budget for restoration following the tsunami covered 98.3 percent of this, but still leaving a substantial cost for the local prefectures. Of the 38 sewage treatment facilities in Miyagi Prefecture, 34 had been restored by 2014, including temporary restoration of 10 facilities. The sea bed was severely disturbed by the tsunami, and most fauna, including the seagrass (Zostera) and the seaweed (Sargassum horneri), which maintain the sustainable cycle of the bay ecosystem, was severely damaged. Although they are gradually recolonizing, more minor fauna, such as bryozoa (Bugula neritina) and barnacles (Balanus spp.) have formed numerous colonies in the intertidal zone as a result of the disturbance in the ecosystem. After two years, a gradual recovery of the seagrass beds was observed where they were previously located.
Most of the initial support for restoration efforts came from private volunteer organizations. Appeals from local inhabitants and fisheries workers sent via the Internet provided information on what was needed. Foreign aid from the United States, Canada and France also helped considerably to restart the oyster farming. The arrival of construction materials for culturing rafts encouraged people to think ahead. Gradually, with government support, the sunken debris was removed. This was done by fishermen, who were paid for this task by the MAFF. This agency also set up a support project to compensate fishermen and farmers for their losses in Miyagi Prefecture in 2013. The combination of efforts by oyster farmers and the state support enabled oyster farming to restart in most of the original fishing grounds. By 2015 87.1 percent of farming facilities were restored. Initially, production of shucked oysters in Matsushima Bay in 2012 was only 12 percent of the average annual production level in 2008–2009. This low production was due to exceptionally high water temperatures in September 2012 (>30°C), causing high mortality in Matsushima Bay. Production has since risen to 314 tons in 2015, 57 percent of the average 2008–2009 production levels (Table 1.1).
The decreasing production has resulted in economic loss and concerns about the viability of oyster farming in Matsushima Bay. There are a few contributing factors, all of which are related to the tsunami.
Since the tsunami, the frequency of Norovirus contamination has increased in all oyster farming areas in Japan, including Miyagi Prefecture. Heat treatment of oysters is currently the only method proven to inactivate the Norovirus. Most of the oysters farmed in Hiroshima Prefecture, the largest oyster producing area, were targeted for the application of heat treatment. Oyster trade was either forbidden by the prefectural government or only allowed for consumption after heat treatment, despite a lower price representing half of its original value. Although the cause of the increased frequency of Norovirus food poisoning has not been officially identified, the increasing occurrence of infections is suspected to be linked to the destruction of sewage facilities. The increasing number of Norovirus-infected patients during winter epidemics raised concerns about water pollution in the farming areas. Even though 90 percent of the sewage facilities were restored in 2014, Norovirus pollution did not decrease.
Consideration should be given to the management of the virus through medical and technological research. The purification capacity of the sewage facilities after the tsunami improved sterilization by adopting the latest technology, but it did not eradicate the virus. Only an additional heat treatment could do so more directly and effectively, but this option is too expensive. Alternative approaches include the storage of uncontaminated oysters by freezing or moving them to virus-free coves, representing a temporary solution for farmers. Such attempts have been tested in several farms but did not prove to be economically feasible. The virus should be ideally eliminated at the point of contamination. Tests using a variety of natural chemicals to inactivate the Norovirus have been tried. Several chemical substances, such as tannin of persimmon and lactoferrin, were found to reduce Norovirus activity (Kamimoto et al. 2014), but no real effective chemical method has been found to eradicate the virus, particularly from the soft tissue of oysters. Although progress has been made in detecting Norovirus, neither an effective means to inactivate it nor the technology to culture the virus for experimental test treatments to avoid propagation has been established. Recently, Enterobacter sp. SENG-6 cells were found to specifically bind to Norovirus, and it is hoped that further technological developments will be discovered (Miura et al. 2013). In the meantime, the rather negative conclusion is that raw oyster consumption must cease, and marketing should shift to selling oysters that have been heat treated. This may result in a decline of the oyster industry.
The warming of the bay temperatures in spring 2013, caused by a change in the ocean current, continued until summer and resulted in early and falling oyster spawning. With the oyster seed collectors being set at the same time as in previous years, less than 15 percent of the expected amount of seeds were collected. In 2014 the period of spat fall shifted two weeks earlier than usual in late June, and there was a change in the distribution pattern of the oyster larvae in Matsushima Bay between 2012 and 2014 (Figure 1.5). Areas of expected dense spat fall were erratic during these three years, and many farmers in Matsushima Bay failed to collect seed. The ongoing shortage of oyster seed following the tsunami brought about the need for collecting seed in other sites throughout Japan, which had depended previously on Matsushima Bay. In order to restore the second-largest oyster seed supply site, research has started to analyze the currents affecting larval movement in Matsushima Bay.
Figure 1.5 Irregularity of the larval settlement at the observed station 12 in Matsushima Bay
Personal communication Shigeru Watanabe (oyster farmer), 2014 (unpublished data)
Additional damages to the oyster industry have been caused by the spread of false information about the effect of radioactive pollution on oysters caused by the explosion of the Fukushima nuclear power plant. This misconception has enhanced the challenge of regaining the trust of customers who are avoiding oysters from Miyagi Prefecture in favor of oysters from other areas.
The consumption of raw oysters has drastically decreased after the Norovirus infestation and, because of their risk management policies, most hotels and high-class restaurants in Japan have removed oysters from their menu. Currently, the average cost to produce 1 kg of oyster was estimated at 832 yen (US$8.15) consisting of shucking labor expenses (19.8 percent), family labor (21.2 percent), materials for farming (9.6 percent), trading (12.0 percent), depreciation (8.8 percent), administrative expenses (7.0 percent), repair costs (4.1 percent), oil (3.0 percent), casualty insurance (3.0 percent), outsourcing (2.6 percent), utility costs (2.2 percent), fisheries exercise fee (2.3 percent), tax and dues (2.1 percent), seed purchase (1.8 percent) and interest charges (0.6 percent) (Inui 2013). The income level of oyster farmers remains below that of a land farm worker. The price of one piece of raw oysters with shell in a supermarket is 100 to 120 yen (US$0.98–1.18) and in an oyster bar 400 yen (US$3.92). This has made oyster farmers reluctant to continue farming. This was particularly prevalent amongst older farmers, some of whom ceased their activity. Between 2003 and 2013, the number of oyster farmers in Matsushima Bay decreased by approximately 10 percent, and there has been a further 5 percent decrease since the tsunami (163 households in 2009 and 116 households in 2016) (Table 1.2). During the same period, the average age of oyster farmers has increased: 56.7 in 2008 and 64.0 in 2013 in Sanriku (Figure 1.6). Low income and heavy work are strong disincentives for the younger generations. Many older farmers can no longer find skilled partners to shuck the oysters for them, and trade in shelled oysters is increasing.
Figure 1.6 Number of fisheries workers by age group
Data source: e-stat 2013 Census of Fisheries Japan
www.e-stat.go.jp/SG1/estat/ListE.do?bid=000001067819&cycode=0
As outlined earlier, the social and economic impacts of the tsunami and consequent Norovirus have affected the viability of oyster farming in Matsushima Bay. Next some future options are outlined.
The oyster industry needs to develop new means of trading, and one option is to use labels. Characteristic features of oysters, including shell shape, flesh proportions, color of the mantle and the taste, depend on the environment in which they are grown. The speed and pattern of growth also vary, even within the same environment. The harvested oysters are all mixed together and shucked by the farmers after depuration. Currently, the Fisheries Cooperative in Miyagi collects all products coming from each branch, raising opportunities to select the best quality for targeted consumers. The farmers are strongly recommended to sort their oysters by their depth position on the suspended rope. Ideally, products should be sorted by size, even when sold shucked. The Fisheries Cooperatives and intermediate buyers should also improve their marketing system to meet different consumers’ demands. A smaller quantity with a larger variety may create higher value for the industry.
Oyster bars that have recently become popular in Japan serve shelled oysters for 500 yen (US$4.95) each. Consequently, the government is granting subsidies to help farmers selling directly to retailers, bypassing the middlemen. However, oyster farmers have been excluded from the marketing aspects for the past three decades, meaning that very few are able to take this up. Because the Fisheries Cooperatives have long been accepting the supermarket prices, price clearing has largely been ignored by oyster farmers. The latter should re-establish a new direct link with customers by grading their products by size and quality in addition to the traditional sales through the cooperative. To promote such practices, national government support (through a scheme to revitalize agriculture and fisheries in the disaster area) has adopted a six-year research project (2012–2017) on oysters in Miyagi Prefecture. Before the tsunami, small shops selling simple oyster dishes were common in Matsushima Bay and were enjoyed by locals and tourists alike. Although destroyed by the tsunami, many new hut-style shops have restarted and serve heated oyster in a covered casserole, generating higher-than-expected profits because of lower costs (no shucking, packing or delivery expenses). This way of serving cooked oysters also ensures safety against the Norovirus.
After the tsunami disaster, the Fisheries Agency provided emergency funds to restart aquaculture in the damaged areas, covering infrastructure and monthly salaries. This state support required the formation of a collaborative group composed of at least three farmers and an operational plan for three years that should release profits for the last year. If the annual production does not reach the appropriate level, the group has to pay back one-tenth of the remaining balance. In Matsushima Bay, traditionally, most farmers engage in aquaculture with family members and have never collaborated with other farmers, except during the harvest, when they used the depuration facility owned by the Fisheries Cooperative. It was therefore a novel experience for them to collaborate with others. Because of the financial support provided by the government, 418 households (including 168 oyster farmers) were given access to the aquaculture projects which included oysters, scallops, silver salmon (Oncorhynchus kisutch), laver (Porphyra), wakame (Undaria) and kombu (laminaria) farming. The government had hoped that this would lead to collaboration in the fisheries society. However, as each oyster farming operation had been run independently for more than half a century, the idea of a collaborative effort may have gone against the pride of individual farmers and made them feel disempowered. To achieve improvement and a better turnover from oyster farming, a process of building understanding and education is needed for an advanced farming operation with further collaboration and mechanization.
Oyster farming in Miyagi Prefecture was already facing a number of challenges in sustaining the industry even before the 2011 earthquake. Profits had diminished due to the changing market conditions (prices are set up by supermarket buyers), an aging population, limited cooperation between family-owned business, low mechanization, tough labor, etc. In March 2011, the disaster came and hit the oyster farming industry in Matsushima Bay. Various societal supports, including provision of farming facilities, enabled the oyster farmers to rapidly make a new start. However, the changes in oceanographic conditions that occurred subsequently have been limiting the further recovery of the industry. Norovirus contamination and oceanographic changes in Matsushima Bay have resulted in further difficulties for oyster farmers. The combined effects of these factors resulted in outbreaks of Norovirus at unpredictable times, as well as an extraordinary annual seawater temperature fluctuation. Former experience and existing practices are no longer applicable. Norovirus contamination has resulted in consumers’ loss of interest in raw oyster and a decline in oyster prices. What is required is an effective virus inactivation measure at the sewage treatment facility to prevent pollution in farming areas.
To deal with these difficulties will require continuous monitoring, research and expertise. Research in artificial culture technology is required to find an effective way to inactivate the virus. Physical or chemical ways of inactivating Norovirus should be applied in all sewage treatment facilities. Oyster farming as a primary industry needs to contend with various natural and social factors, all of which contribute to the sustainability of oyster farming. Continued scientific and social research must support this historical industry, which relies on so many factors for its rehabilitation. The I-ADApT framework provided a useful template to collect data and analyze the past and present situations, short-term and-long term means to recover, required research and social concerns.
The editors wish to acknowledge the precious support of Dr. Yinji Li, Tokai University, Japan, who helped edit this chapter.
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