The more you know, the tastier they become! Kesennuma oysters

Kesennuma is known as one of Japan's leading oyster farms. Many oyster rafts float in the calm bay, and forest maintenance and reforestation have been carried out since ancient times upstream of the Okawa River, which carries nutrients from the forest into the sea. Oysters, which feed by absorbing up to 1 liters of seawater a day, can be said to be the very embodiment of the "workings of the forest and the sea." Oysters grown in Kesennuma Bay are large and rich in flavor. The aroma and flavor of the seashore fills the mouth at once.
Here, we would like to tell you about Kesennuma oysters from various perspectives!

Story 1: Kesennuma oysters are hand-raised

In order to grow delicious oysters, it is important to put in the time and effort. Kesennuma oysters are cultivated through a variety of processes.

Growing mountains for the sea

Kesennuma Bay is a long, deep bay. There is a large brackish water area where fresh water from the rivers that flow into the bay mixes with sea water, and this brackish water area contains an abundance of plankton that flows from the upstream of the river. Oysters grow large by eating this nutritious plankton. Plankton is nurtured by the forests in the river basin. Kesennuma fishermen realized the importance of forests from an early stage, and have been engaged in reforestation activities to protect the richness of the sea.

Soak in hot water to plump up the flesh

There is a process called "hot water treatment" for oysters. This is the process of lifting oysters that are growing in the sea and immersing them in a tank of 70 degree hot water installed on the boat for about 15 to 20 seconds.
This is done to kill the seaweed that grows on the shells. Oyster shells are thick, so the meat is not affected even when soaked in 70 degree water. This provides the oysters with the nutrients they need, which helps make the meat thicker.

Rough seas help develop the delicious flavor of oysters

The oysters produced in the Karakuwa area of ​​Kesennuma, known as "Momare oysters," are moved from the calm waters of the bay to the fast currents of the open sea as they grow. This is a farming method unique to the indented ria coastline of the bay.
Oysters grow slowly in the inland bay, storing up plenty of nutrients, and when they are rubbed by the tide, the meat becomes firm and the flavor is concentrated.

Story 2: What is oyster farming?

The term "hot water treatment" was mentioned in relation to oyster farming in Kesennuma, but I think many people don't really understand what exactly oyster farming entails. So, this time we asked Mr. Kayaoka, a curator at the Rias Ark Museum of Art, to summarize oyster farming in Kesennuma.

When you hear the term oyster farming, many people probably imagine a raft floating on the sea.

▲ Oyster farming rafts floating in a calm inland bay

Indeed, there was a scene in the drama where they were working on oyster rafts. The image is of a raft made of wood or bamboo that is floated on the sea, and the oysters are dropped into the sea from the raft. However, the main method of oyster farming in Kesennuma is to drop anchors into the sea and stretch ropes.

▲Oyster farming using longline method

▲ Conceptual image of longline aquaculture (Illustration: Hiroyasu Yamauchi)

Why are there two types of aquaculture methods, using rafts and ropes? This is because it is necessary to use different facilities depending on the sea area where the aquaculture facilities are installed. Rafts are a method suitable for inner bays with calm waves, but they cannot be installed in places with high waves because they will break.20The longline farming facilities developed in the latter half of the 1990s were highly resistant to waves, making it possible to farm in the open ocean where the waves are strong and the tides flow well. Currently, oysters, scallops, sea squirts, wakame seaweed, kelp, and other seaweed are farmed using longlines.

How delicious oysters are made

① Seed clamp

Oysters spawn in the summer, and the larvae drift through the ocean and attach to any solid matter they find to become shellfish (seed oysters). In Mangokuura, Ishinomaki City, Miyagi Prefecture, scallop shells are sunk into the ocean during spawning season, allowing the larvae to attach to them and collecting seed oysters. In this area, these are purchased in early spring, and the scallops with seed oysters attached are placed between the twists of a rope and lowered into the ocean. In "Okaeri Mone," Mi-chan researched the industrialization of "home-harvesting," harvesting seed oysters herself instead of purchasing them from outside, as a high school student.

▲ Seed oysters are caught in the hanging rope. The small shells attached to the surface of the scallop shells are oysters. These will grow into big, beautiful oysters.

②Grows well!

Oysters do not need to be fed like fish when they are cultivated. Oysters grow rapidly by feeding on plankton in the sea. However, this does not mean that they can be simply left alone. For example, care must be taken to ensure proper growth, such as removing and thinning out attached organisms and repairing the cultivation facilities. In the Karakuwa region of Kesennuma, the hanging locations of the oysters are skillfully changed according to their growth, and the grown oysters are carefully separated from the clumps and grown, and finally placed in cages and hung in fishing grounds with good tidal flow to grow them, which allows them to grow large, meaty oysters. These oysters have been branded under the name "Momare Oysters."

②Hot water treatment

Hot water treatment is the process of eliminating mussels and other organisms that attach to oysters and inhibit their growth. Oysters are placed in water at a temperature they can tolerate, which kills other organisms that have attached to the shells, allowing the oysters to monopolise all the nutrients. It is hard work, carried out in midsummer, but it is this effort that helps produce delicious oysters.

▲The hot water treatment. The densely packed black shells are oysters. If the temperature or time is not correct, the oysters will die, so extreme care must be taken. (Interview cooperation: Yamayo Suisan)

③ Oyster peeling

▲ Oyster shucking work. In recent years, the shortage of workers has become an issue. (Interview cooperation: Toba Taira)

Oysters are landed in this area from around November until early spring. The task of peeling the shells is the job of women called mukiko. They insert a knife from the outside to remove the adductor muscle, open the shell, and then peel the oyster away without damaging the meat. Because the shape of the shell and the position of the adductor muscle vary slightly depending on the oyster, this must be done by hand rather than by machine, and is a seemingly simple but difficult "artisanal" task.
By the way, oysters are often thought of as a winter food, but spring oysters, which have stored up plenty of nutrients before laying eggs in the summer, are the tastiest and best of the year! If you have the opportunity to eat them, please do try them! (For more details, see this article:Kesennuma Sea Flavors and Mountain Flavors No. 7" Article link)

Story 3: I want people to know how amazing oysters are!

Oysters are said to be rich in nutrients and to be very good for the body... I think many people have some idea of ​​this. In fact, the greatness of oysters, which is not well known, will be introduced by oyster-loving writer Kazue.

No muscles! Oysters are mostly internal organs

Oysters stay still in the ocean. They can't move. Since they can't go out and catch food by themselves, they suck in seawater to ingest the high-quality plankton in it. It's said that they suck in as much as a bathtub full a day.
With that small body, they have the power to take in that much seawater in a day. What unfathomable strength! And because they can't move, they have almost no muscles (or equivalent organs). That means most of their body is "internal organs." Therefore, a major characteristic of oysters is that nutrients are stored in every nook and cranny.

Rich in zinc! (Also rich in selenium!)

Oysters are rich in minerals and vitamins. Many of them are contained in a well-balanced amount. The most notable among them is zinc.
Zinc has the ability to improve immunity and repair cells, supporting various bodily functions. It is also essential for protein synthesis.
Most of the human body, including skin, nails, hair, and of course muscles and internal organs, is made up of protein, so regenerating proteins damaged by illness or fatigue is essential for both health and beauty.

Rich in taurine and various vitamins!

Oysters are also rich in taurine. Famous for its "Fight One Shot" flavor, taurine is said to be good for recovering from fatigue, but it also has the effect of reducing cholesterol and suppressing high blood pressure, making it effective in preventing high blood pressure.
First of all, vitamins and minerals are not just about "eating a lot of this," but it is important for the body to consume a variety of them in appropriate amounts in a balanced way (this is important). The great thing about oysters is that they contain a good balance of many different vitamins, minerals, essential amino acids, and more. Japanese people today are taking in enough calories (maybe too many?), but they are not getting enough vitamins and minerals from their diet. They take in vitamins through supplements, but they tend to be deficient in minerals. Oysters are a wonderful food that can make up for this. Oysters are a powerful thing.

The history is amazing!

Oysters were already mentioned in the medical book "Compendium of Materia Medica," published during the Ming Dynasty in China (which was later published in Japan during the Edo period and had a major influence on modern Japanese pharmacology).
"When boiled and eaten, it heals feelings of emptiness and psychological disorders, tones the body, eliminates erysipelas, and improves the flow of blood and energy in women. When eaten raw with ginger vinegar, it cures erysipelas, reduces fever after eating and drinking, and quenches thirst. When roasted and eaten, it is very delicious, and it tones and beautifies the skin." (Compendium of Materia Medica, Volume 46, Vol. 23)
It is written that oysters are good for your health (and for your beauty!) It has been known for 500 years now. By the way, it seems that oysters have been eaten in Japan since the Jomon period. A lot of oyster shells have been excavated from shell mounds from the Jomon period.
People in the past also knew what was good for the body and delicious.

And it's delicious!

Oysters are so wonderful. But what makes us happiest is that they are delicious. In the past, the oyster season was said to be "months that start with the letter R" (September to April), but now, due to the effects of global warming, the season often starts around October. Furthermore, thanks to the efforts of producers, we can now enjoy delicious raw oysters until early spring, around May.
In Kesennuma, the number of restaurants offering oyster dishes is on the rise. It's a happy cry. There are various ways to enjoy the deliciousness of oysters, but to increase the absorption rate of zinc and iron, it is effective to combine oysters with foods containing vitamin C (lemon, onion, etc.).

Fried oysters with lots of lemon are a must. Lemon-flavored butter sauteed oysters, Chinese stir-fried oysters and broccoli (maybe using Ishiwata Shoten's oyster sauce will give you even more oyster power?), oyster and spinach gratin. Oyster marinade with lots of lemon and onion is also good. This is a particularly recommended way to eat oysters for women who are concerned about anemia or rough skin. Please give it a try.