One bright blue February afternoon, Akira Harajo stood on a concrete pier and surveyed Mie Prefecture's Ago Bay. With dyed black hair, a zippered sports shirt and immaculate V-neck sweater, Harajo, 75, hardly looked the part of the farmer that he is. Then again, his crop isn't exactly ordinary: Harajo grows jewels.

For eight decades and three generations, Harajo's family has harvested top-quality pearls from this scenic bay 3 hours' drive southwest of Nagoya — the birthplace of the world's cultured-pearl industry. However, those pearls and the Akoya oysters (Pinctada fucata) they grow in took a terrible toll of the marine environment.

"There used to be all kinds of things in the bay — swimming crabs, clams, sea bass, mozuku seaweed and sea cucumbers," recalled Harajo. "But for about 30 years now there have been almost no eels, and for 10 or 15 years no Japanese littleneck clams. And it was us pearl farmers who polluted the bay."

Overproduction, along with wetland- reclamation projects and pollution from a growing residential and tourist population whose sewage and waste water was flushed directly into rivers, turned the once-bountiful bay into an environment hostile to much aquatic life.

Now, facing a depleted natural environment and a flood of cheap, high-quality pearls from China and elsewhere, Harajo and other farmers — along with scientists and city officials — are rethinking their relationship to the bay.

"The world's cultured-pearl industry started in Ago Bay, so people here have a lot of pride," said Hideto Uranaka, chief of marine products resources at Shima City Hall (the municipality surrounding Ago Bay) and coordinator of a project to revamp how the city uses its bay. "But if the ocean isn't clean, you can't grow good pearls. It's not just the pearl farmers; the whole region has to care for the bay."

Thanks to its tuna, dolphin and whaling policies, Japan's worldwide image is increasingly that of a ruthless exploiter of marine resources — but Shima and a few other coastal communities nationwide are searching for a sustainable future.

Slowly, and in the face of often- frustrating bureaucratic obstacles, these communities are establishing management practices that recognize the link between long-term economic productivity and ecological health. They call coastal landscapes where humans play a beneficial role satoumi — combining the words for village (sato) and sea (umi).

"Coastal seas must have high biodiversity and productivity, and then fishermen can get a part of that. The most important thing is to consider the sea as a habitat," said Tetsuo Yanagi, an oceanographer at Kyushu University who coined the term satoumi in 1997.

Japan adopted the promotion of satoumi as a national policy in 2008's Basic Plan on Ocean Policy, as well as in strategic plans from the Environment Ministry and the Ministry of Agriculture, Forestry and Fisheries. Ago Bay is one of five model project areas the Environment Ministry is monitoring to create a satoumi "manual" other regions can use.

Humans have been part of the Ago Bay ecosystem for thousands of years, both adding nutrients in the form of wastewater and removing them in the form of fish, mollusks and seaweed. Divers began gathering rare wild pearls there at least as long ago as the eighth century.

However, it was only at the turn of the 19th century that researchers discovered how to plant a fragment of hard material in an oyster's gonad, stimulating the animal to coat it with layers of mother-of-pearl and so ensure humans a regular supply of perfect spheres (controversy exists over whether it was English marine biologist William Saville-Kent or Japanese researchers Tatsuhei Mise and Tokishi Nishikawa who pioneered the technique).

Meanwhile, local entrepreneur Kokichi Mikimoto developed a way to create semispherical pearls. In the early 1900s, he began producing round pearls on a commercial scale, launching a new global industry. Mikimoto was soon a synonym for ultimate elegance, his Ago Bay pearls gleaming in jewelry cases from Tokyo's glitzy Ginza to Paris (where they may still be admired today).

Then, after the end of World War II, export restrictions were loosened and pearl production skyrocketed — by twentyfold in Mie Prefecture between 1950 and 1965. Other types of commercial fishing in Ago Bay essentially stopped.

"One pearl was worth as much as a meter-long tuna," explained Harajo, who at the peak of production harvested 800,000 pearls a year (today his son sells about a 30th of that number) and traveled from Las Vegas to Italy on the profits.

In theory, pearl production should have improved the health of the bay. To grow pearls, farmers suspend multilevel wire baskets from floating rafts and stock them with oysters. After two years, they insert a nucleus, and after another year or two they harvest a single pearl. All the while the farmers tend the sensitive mollusks carefully, moving them to warmer locations in winter and cooler ones in summer, and cleaning the shells several times a year to remove worms that cause disease and smaller shellfish that compete for waterborne food.

Meanwhile, the knobbly 6-to-8 cm-long bivalves continuously pump water into their shells to filter out plankton — bringing particulates, nutrients, and even heavy metals, into their digestive system at the same time. The plankton becomes oyster food, while nonfood materials are packaged in mucus and excreted. Because floating particles collect either in the oyster itself or in solid clumps on the seafloor, water quality improves.

In Ago Bay, however, farmers grew so many oysters that the seafloor became covered in droppings. They also threw debris scraped from shells and the oyster meat left after pearls were harvested back into the water. As bottom-dwelling, or benthic, organisms broke down these materials, they consumed large amounts of oxygen. This led to a state of extremely low oxygen levels in the water, called hypoxia, which killed many benthic organisms and fish. In the mid-1990s, hundreds of millions of oysters died off as well, possibly from related causes.

Today, aonori seaweed production has largely replaced pearl production in Ago Bay, but hypoxia still occurs every year. That's because the pearl industry is not the only cause of the problem. The volume of residential wastewater flowing into the bay has also increased over the last century, causing harmful algae blooms. By the 1960s as well, 69 percent of the bay's tidal flats had been turned into rice paddies. Tidal flats play a critical role in filtering nutrients from the water.

In 2000, in the face of ongoing economic and environmental decline, a small volunteer group led by Harajo began using sediment dredged from the bay to create artificial tidal flats. That project grew into a 5-year initiative — funded by Mie Prefecture and the national government and involving about 80 researchers — to monitor Ago Bay's environment and test a number of restoration technologies there.

These included an automatic water- quality monitoring system that scientists and fishermen can access via cell phone, and an experimental project to restore water circulation between the bay and a reclaimed area that increased benthic organisms tenfold.

Though the national project has ended, Shima's mayor, Hidekazu Oguchi, has made satoumi-based management his top policy priority. Shima City and the prefecture, via the Mie Fisheries Resource Center, continue to fund related projects and publicize their work at international conferences. However, no laws exist to regulate waste from the oyster industry, and human use, including aquaculture and fishing, is still permitted in all areas of the bay.

Uranaka and others involved in the projects say divisions within the government and low public awareness pose significant challenges.

"In Japan there's no unified system of management. Even in our City Hall there is sectionalism. If I suggest something, people say 'You're just the fishery guy,' " Uranaka said. "Until now, the only ones who were concerned about problems in the bay were the fishermen."

But for pearl farmer Harajo, preserving the bay for the long haul is the only option.

"I feel this is my work, and I have hope," he said. "I've been living on the sea my whole life. I can't imagine life without it."