Yamada Bay Oyster & Scallop Aquaculture Landscape was added to Your Favorites!
Bandai Asahi NP, Iwate
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Yamada’s shell-on oysters grow for 3 years—one year longer than the 2-year crop common elsewhere, making especially large shells. At the bay-view kaki-goya, they’re steamed and served one after another, like “oyster wanko-soba.”
Since March 27, 2018, 839 hectares of Yamada Bay have been protected as a marine park zone in Sanriku Fukko National Park—not just for nature, but for the calm bay, central island and orderly oyster-and-scallop rafts, recognized as a cultural seascape.
In late April, drifting scallop larvae pass wakame farms; onion-mesh bags hung from their rafts can catch some. The wild seed grows to about 10 cm in 2 years, though local catches are too small to supply every farm.
European flat oysters, brought in for an aquaculture trial in 1991, have been found among Yamada Bay’s farmed shellfish since about 2002. A 2024 DNA-backed study concluded that this European species had established a self-sustaining population here.
The larger island among the rafts is Ōshima, better known as Olanda-jima. In 1643, the Dutch ship Breskens anchored nearby for water and food, then made a second visit to Yamada Bay.
At about 7 cm, each scallop is lifted ashore, pierced through its shell’s protruding “ear,” and threaded onto a rope. It then returns to Yamada Bay for about 2 more years of suspended growth.
After the 2011 tsunami, fishers cleared debris from the bay by day and agreed on new raft spacing at night. Local producers later credited the less crowded layout with giving scallops more food—and a sweeter taste.
A 1902 record already mentions oyster farming in Yamada, though it expanded around 1955. In the 1970s, Oosawa’s cooperative developed a “single-oyster” technique, helping make large shell-on oysters a local specialty.
Some oysters begin as tiny juveniles attached to scallop shells brought from Miyagi. Farmers split the grown clusters, pierce each shell near its tip, then hang the oysters individually for 6–12 months and purify them in clean seawater for 2 days.
Yamada Bay’s underwater eelgrass meadows are made of flowering plants, not seaweed, and include unusually diverse communities. They shelter marine life, but Ministry monitoring found eelgrass sparse along most inner-bay shores after the 2011 disaster.
