One summer’s day at the ebb tide, we arrive at Taiwan’s largest oyster-producing locality: Dongshi Township. We follow Chen Changhua and her father-in-law Huang Changli as they head to the Shoudao Sandbar just off the coast to harvest oysters.

Huang’s old-fashioned farm truck with a single front wheel makes a “putt-putt-putt” sound as it jolts forward along the track next to the oyster field amid the sea breezes, attracting a lot of attention. The truck stops on a patch of concrete, from where we switch to a raft which Huang steers to the side of the oyster racks using a pole. Next, he and his daughter-in-law disengage the shellstrings hanging from the ropes tied between the standing poles of the racks and begin to harvest oysters. As they repeatedly untie the strings and gather oysters, three hours quickly pass.

Women in oyster farming areas can earn enough money to feed a family by wielding a shucking knife.

An oyster farmer goes into the water of an oyster bed to wash algae and sand off the shells of freshly harvested oysters.

Oyster harvesting

After harvesting the oysters they need on this day, they steer the raft back to the beach, where Huang uses a pry bar to break apart the clumps of oysters on the strings, and Chen places the oysters in baskets and rocks the baskets to and fro in the water to rinse algae and mud off the shells. Finally, they load the oysters onto the truck and return home to shuck, pack, and ship them.

What we have seen is the second half of the oyster farming process. Before it came the labor-intensive tasks of piercing oyster shells and threading them onto strings, and culturing the oyster spat (the larvae that attach themselves to the shells). In my mind I hear the lyrics of the song “Dongshi” by Wu Bai, which tells of the arduous labor of harvesting oysters of 50–60 grams weight with nowhere to hide from the intense summer sun or blustering winter wind.

In the vast oyster grounds, there is no place to hide from the summer sun nor to shelter from cold winter winds. Oyster farming is arduous work.

Chen Changhua, the lady boss at “Baishuihu Kexuejia,” transformed her family’s home into an experiential tourism venue that teaches visitors about oysters.

Oyster studies

Chen Changhua and her husband, Huang Feilong, returned to Dongshi to take over the reins of the Huang family’s oyster farming business during the financial tsunami of 2007–2008. The two founded the “Baishuihu Kexuejia” brand and transformed their home into a venue for experiential tourism and leisure. Through oyster farm tours including explanations of oyster ecosystems, and hands-on learning activities such as piercing oyster shells and threading them onto strings, or shucking and grilling oysters, they spread knowledge about these creatures.

Chen Changhua explains the greatest benefit of these “oyster studies” classes: “Many people are squeamish at the thought of eating oysters because they think of them as having a fishy smell and squishy flesh, but after coming here they change their minds.”

Most oyster farms set their oyster racks close together, but at Kexuejia they have adopted low-density aquaculture, with wide spacing between the rows of standing poles that make up the racks. This ensures that their oysters get plenty of food. In addition, while most farmed oysters are harvested at six months to a year old, at Kexuejia the oysters are grown for two to three years before harvest, so they are as big as oysters raised to be eaten raw. Chen says that these more mature oysters have a firmer texture and no fishy smell. However, they are more difficult to shuck.

In Dongshi Township one can often see strings of oyster shells used for decorative purposes.

Dongshi Fishing Harbor is open to tourists and has become a popular place to stroll around and gaze at the ocean.

Oyster meat is very nutritious and is a popular food with ordinary people. Snacks like oyster vermicelli, oyster omelet, and deep-fried oyster dumplings are widely loved.

Authentic taste of the sea

Oysters (family Ostreidae), known in Mandarin as muli or hao and in Taiwanese as ô-á, are a common food consumed by ordinary people, and snacks such as oyster vermicelli and oyster omelet are widely available and highly nutritious. Dongshi Township chief Lin Junxiong, formerly secretary-­general of the Chiayi Fishermen’s Association, explains that the outstanding mouthfeel and rich taste of oysters farmed in Taiwan are thanks to the use of traditional aquaculture methods.

In Taiwan, oyster farming is a major form of seafood aquaculture practiced along the West Coast, mainly in Chiayi, Yunlin, Changhua, and Tainan, as well in the Penghu Islands. All of the oysters raised in Taiwan are of the species Magallana angulata. According to data from the Fisheries Agency, from 2005 to 2007 Taiwan produced about 30,000 metric tons of oysters a year, making it the world’s sixth largest producer. In recent years, annual production has been about 18,000 tons, with Chiayi’s two coastal townships, Dongshi and Budai, accounting for 47%, making the county the nation’s top producing region.

Lin Junxiong notes that oyster farming is vulnerable to the wind and waves brought by southwesterly weather fronts and typhoons. The Waisanding Sandbar off Dongshi acts as a natural barrier against the open sea, and there are no large industrial zones in Chiayi, so the waters are especially rich in plankton. Such factors have enabled oyster aquaculture to develop on a large scale in Dongshi, growing large, plump oysters that produce a white color when cooked into soup, earning them the moniker “milk of the sea.”

Oysters filter-feed on plankton, and the aquaculture methods used in Taiwan include suspended culture, rack culture, raft culture, and long-line culture, depending on the depth of the water. Oysters are at their meatiest from April to October each year, and consumer demand is especially high for the barbecues that are widely held around Mid-Autumn Festival. In oyster farming areas, one can often see local women gathered in huts shucking oysters, with heaps of waste shells frequently becoming part of the local scenery.

Because Dongshi is a bastion of oyster aquaculture, oyster shucking is an activity that involves virtually the whole town. Lin Junxiong explains that one shouldn’t underestimate the impact of this work, for “one oyster shucking knife can support an entire household.” In the main production areas in particular, people can earn NT$1,000–2,000 per day at this job.

In Dongshi, some six to seven households out of ten are involved in oyster shucking. Because of the high value of oyster production, in recent years a “grilled oyster street” has developed near the Dongshi Fisherman’s Wharf, attracting numerous tourists.

In recent years the quantities of oysters imported into Taiwan have been steadily increasing, and the Chiayi County Government has pro-actively helped fishermen to adopt a traceability system for their oysters, under which they attach a Traceable Agricultural Products QR Code to their products, thereby enhancing consumers’ confidence that they are getting genuine Dongshi oysters. The county government has also assisted in converting five oyster shucking spaces into environmentally controlled demonstration sites that can be kept at cold-room temperatures, where the oysters are packed into insulated cold containers to keep the meat fresh and of premium quality, thereby enhancing the brand reputation of Dongshi oysters.

The Chiayi County Government has helped oyster farmers to introduce a traceability system with QR Codes on products, in hopes of raising consumer confidence.

Farmers bring their harvested oysters ashore and send them to oyster washing facilities to be cleaned.

Dongshi produces vast numbers of oysters. In recent years it has promoted recycling of oyster shellstrings and ropes in the interests of environmental protection.

Wide separation between oyster racks helps the oysters grow large.

The future of oyster shells

Oysters earn a great deal of money for Dongshi and the town boasts Taiwan’s largest oyster washing venue. Oyster farmers from other areas send their oysters to Dongshi to be washed, shucked, and sold on, resulting in Dongshi generating the most waste oyster shells in Taiwan—about 90,000 tons per year—with no place to dispose of them.

In the past these oyster shells were just piled up willy-­nilly, and over time the residual meat in the shells began to produce an unpleasant odor and attract flies and mosquitoes, becoming a blight on the land.

A few years ago, the Environmental Protection Administration (now the Ministry of Environment), the Chiayi County Government, the Taiwan Sugar Corporation (TSC), and industry stakeholders worked together to first resolve the problem of waste oyster shell heaps, and then assist in the development of industrial uses for oyster shells, in addition to their existing uses in agriculture. This transformation of waste oyster shells into gold has become a new page in the story of the development of the circular economy in Taiwan.

Initially, the Chiayi County Government won support from Dai Sentai, head of the Jijin cooperative, Dongshi’s largest private-sector oyster washing operation, to use his own private land to build an environmentally compliant temporary storage facility. Through ground preparation, installing a waterproof liner and building protective fences, the site’s design prevents the waste oyster shells from further polluting the environment.

Meanwhile, TSC built Taiwan’s first new-style oyster-­shell processing plant in Tainan’s Yongkang District. It can handle some 50,000 tons of shells per year, turning them into 40,000 tons of calcium carbonate, which is supplied to industrial users. Sun Ling-ming, CEO of TSC’s Biotechnology Business Division, says that the processing plant has three dust collection systems. The dust collected during processing is used as fertilizer, enabling the whole plant to achieve the goals of “zero pollution” and “zero waste” and set a new example for the practice of the circular economy.

Ground oyster shells can also be manufactured into bespoke powders of different particle diameters and supplied to customers for multiple applications.

The Taiwan Sugar Corporation has built a new oyster shell processing plant which grinds waste oyster shells into powders for industrial use, thereby greatly increasing the value-added of oyster shells.

Crushed oyster shells can be used in fertilizer and animal feed, and even as a raw material for making ceramics.

Diverse uses of oyster-shell powder

TSC shows us oyster-shell powders of various particle sizes. Meanwhile Formosa Plastics has developed an oyster-shell powder with antibacterial properties, and combined it with plastic raw materials to develop antibacterial compounds for use in plastic products.

B&M Caiman, a brand produced by Decheng Footwear, used antibacterial oyster-shell powder from Formosa Plastics to develop “Y-thong” running sandals. Top Taiwanese ultramarathoner Lo Wei-ming wore these Made-in-Taiwan sandals in competitions, making them an overnight sensation. Also, Everplast Machinery Company worked with National Cheng Kung University to add oyster-shell powder to cement to produce an environmentally friendly structural building material.

Other companies are using the powder in textiles, opening up yet another realm for oyster shells.

Zhang Huichuan, director of the Chiayi County Environmental Protection Bureau, says that when oyster shells are used as an animal feed additive or soil amendment, they can generate NT$20,000 per ton in economic value. If used as an antibacterial functional material for footwear, the value per ton can reach NT$980,000, enhancing the economic benefits of recycling oyster shells.

Dongshi Township built its reputation on oysters, and has also faced environmental problems because of oyster shells. Today, this small fishing community recycles oyster shells in a circular fashion, riding the wave of a global trend. This also demonstrates that a traditional fishing village, if it puts its mind to it, can be in the vanguard of the move towards the circular economy.

Finding new uses for oyster shells encourages aquaculturists to recycle waste shells and has put Dongshi in the vanguard of the circular economy.