To raise and protect Ayu from the Shogawa River. That is the challenge of Yamada Shoji.

In recent years, natural Ayu from the Shogawa River, beloved by many Japanese restaurants, including specialized Ayu cuisine establishments from early summer to late autumn, has been steadily declining due to various factors.
Yamada Shoji has been committed to ensuring the consistent deliciousness of Shogawa’s Ayu for consumers by focusing on complete Ayu aquaculture．
Today, we boast an annual shipment of Ayu ranging from 1 to 1.2 million, nearly monopolizing the production of live Shogawa Ayu that major restaurants procure.

　In 1993, we completed the construction of the first dedicated Ayu cultivation facility in Hokuriku, Japan, nurturing Ayu from the fry stage using water from the Shogawa River. Since autumn 2019, in collaboration with the Toyama Prefectural Fisheries Experimental Station, we have been attempting to increase the production of “Kissui no Shogawa-Ayu” through complete aquaculture, starting from native Ayu from the Shogawa River.

Ayu’s flavor and aroma vary remarkably depending on the water it grows in. Cultivating Ayu in the waters of the Shogawa River is the most important factor since Ayu raised in the water of the Shogawa River are characterized by their tender bones and skin, as well as a pleasant aroma. The result of an experiment where fry hatched at the same time were raised in water from the Shogawa River and water from other prefectures showed significant differences in appearance, taste, and aroma. This is believed to be due to factors such as the type of algae eating as food and the pH level of the water.”

Ayu which are sensitive to environmental changes are notoriously difficult to rear. Firstly, the spawning season for wild Ayu lasts only around 10 days per year, limiting the timing for egg collection. Furthermore, the first generation born from the eggs of wild Ayu are not accustomed to the conditions of aquaculture, making them particularly delicate. Moreover, due to the natural behavior of Ayu, it is necessary to replicate the environment of migrating from rivers to the sea and then upstream in rivers as they grow, and accordingly adjust their diet. Additionally, it is essential to cultivate animal plankton, which Ayu would naturally feed on in the sea, while also considering vitamins and other nutrients. Careful attention must be paid to both the feed itself and the method of feeding. Since Ayu die after spawning in the autumn, we rear a considerable amount of a consistent quantity with a time lag, taking into account the shipment and consumption for our specialized Ayu cuisine restaurant.

In autumn 2019, approximately 20,000 fry hatched from fertilized eggs of wild Ayu. Our challenge is to carefully rear and increase their numbers from here, so that they can be released into the Shogawa River. In the past, passing a set net through the Shogawa River would yield dozens of Ayu every time. Nowadays, such catches happen maybe once a year, if at all. We aim to restore the Shogawa to its former glory and continue to uphold the Shogawa brand. Preserving the Shogawa brand is our mission at Yamada Shoji.

Continuously pursuing “Kissui no Shogawa-Ayu”
(Registered Trademark)

Our fish farming facilities are divided into two locations to diversify risks. We draw up to 4 tons of water from the Shogawa River per minute from a depth of 14 meters, and rear the fish in 10 ponds. We do not adjust the water temperature at all, maintaining conditions as close to the natural state of the Shogawa River water as possible.　 To minimize any disturbance to the Ayu, even the slightest amount of bacteria, outsiders are strictly prohibited from entering.
The fry we raise from the eggs of wild Ayu have a transparency to their bodies. This transparency is unique to the fry of wild Ayu, and as generations pass, the fry raised in aquaculture become darker. These fry, indistinguishable from wild ones, are then raised in brackish water areas where seawater and freshwater mix, before transitioning to freshwater cultivation.

The adult fish just before shipment are kept without feed for a full day and a half, ensuring that all waste is completely eliminated before shipment. This is part of our commitment to the Shogawa brand, aimed at maximizing aroma and flavor.

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  Catching wild Ayu

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  After squeezing the eggs from the gravid Ayu and artificially fertilizing them,

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  they are attached to a brush-like structure made of woven branches to allow for hatching

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  About one-third of the total number of fertilized eggs will hatch, indicated by the formation of black eyeballs. They are reared in freshwater until hatching.

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  The first generation of Shogawa Ayu raised through artificial cultivation. They have a yellowish tinted adipose fin and a large dorsal fin. Their elongated face is a characteristic feature of wild Ayu.