Simplicity is key to Rikusui’s land-based aquaculture success in Osaka

Published on
May 20, 2022
A Rikusui employee standing in the company's main building.

Though numerous land-based aquaculture projects are in the works in Japan, there are questions as to whether these new start-ups will be able to turn a profit.

One small-scale start-up producer near Osaka, Japan, is already operating in the black and showcasing how to succeed at land-based aquaculture using something other than an recirculating aquaculture system, which have become the most-popular choice for new land-based farms being built in Japan.

SeafoodSource visited the production facility of Rikusui Co., at Tannowa harbor, in the town of Misaki at the south end of Osaka prefecture, which successfully operates land-based aquaculture operation farming rainbow trout and tiger pufferfish.

According to the company, a major part of its success is having a favorable site for the aquaculture system it uses. The building in which the company’s tanks are located was formerly used to sort and auction off the catch of the local fishermen’s cooperative. As fishing activity in Osaka Bay declined, the auctions were discontinued and the building fell into disuse. Such buildings are present at many local fishing ports in Japan, and many of them are now sitting idle. However, Rikusui's has the added advantage of being located within an hour’s drive of the major urban market of Osaka.

Rikusui's building was leased at a reasonable rate, with the cooperative retaining a little space with small tanks for holding live fish. Built on reclaimed land at the port, the building was also already equipped with a saltwater well and pump. The saltwater in the well has been naturally filtered through the soil, so it is safer in terms of parasites than water taken directly from the sea. Rikusui then added on a UV treatment to ensure its water is sterilized.

In Rikusui’s part of the building, there are three tanks: A 60-metric-ton capacity tank currently stocked with 3,000 tiger pufferfish, and two more 30-metric-ton tanks holding 1,500 rainbow trout each.

The operation is not a RAS. Saltwater is pumped from the well, UV sterilized, and used with no salinity, pH, or temperature adjustment. The rate of exchange for the tank water is about three to four times per day, and used water is discharged to the sea without treatment. Oxygen levels in the tanks are maintained using a control box and oxygen tanks supplied by Tokyo-based Tomoe Shokai Co. The system has a function that will send alarms to the company’s staff if oxygen levels are outside of the correct range or if other problems are detected.

Because there is no heating or cooling of the water, the species farmed are rotated by season to suit the ambient water temperature – even though that means that some species are brought in partially grown and finished at Rikusui. Though buying fish only a few months from maturity costs more than buying them at a smaller stage, by rotating them according to season, the company avoids heating and cooling costs while getting a premium price for freshest delivery. The farm started by finishing off partially grown longtooth grouper from Nagasaki, which is caught from September to December.

Blowfish are fed at the site for 16 months, beginning in August and terminating in December of the following year. In Japan, Nagasaki is the major blowfish producer, but Osaka is the main consumption center, giving Rikusui an advantage, as it is able to offer a fresher product.

Rikusui stocks partially-grown rainbow trout from January through May and sells them from March through May, because summer in Osaka is too warm for them to grow in the farm. In Japan, rainbow trout farmed in saltwater is usually called “trout-salmon” and is considered as a legitimate substitute for salmon. Thus, in its website and promotions, Rikusui compares its “salmon” – delivered within hours of harvest to sushi shops and “izakaya” pubs in Osaka – to airflown Atlantic salmon from Norway, which takes days to arrive in Japanese restaurants after being harvested.

Rikusui sells directly to restaurants and carries out the deliveries themselves. Rikusui CEO and Representative Director Yuki Nasu said the company prefers to do its own delivery and takes orders as small as one fish, which are harvested and bled using the ikijime method, then iced in a box and sent out for same-day delivery.

Nasu said prices and demand for the company's products are high now due to the closure of Russia’s airspace, which forces a longer rerouting of Norway’s air shipments. That has given Rikusui an added boost, he said.

“[However], we would still make a small profit, even at normal price levels,” he said.  

Photo by Chris Loew/SeafoodSource

Contributing Editor reporting from Osaka, Japan

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