According to The Gas Review, gas demand for the marine products industry is gaining attention, again.

At the centre is supplying oxygen to breeding ponds to promote more effective growth of farmed fish through oxygen enrichment.

Business is expanding past the supply of oxygen to fish farms toward the sale of oxygen dissolvers for efficiently spreading oxygen in breeding ponds and even sales of complete fish farming systems.

Behind this is the increasing popularity of land-based fish farming in water tanks installed on land.

The Fisheries Agency has been promoting the development of fish farming technology to expand exports of Japanese-farmed fish centred around salmon, which is experiencing increasing global demand over the last few years.

Traditionally, fish farming involved mainly ocean farming where ponds were separated near the coast using nets or other means.

Now, the spotlight is on land-based fish farming where installation locations for breeding ponds are not limited to the coastline.

There are two types of land-based fish farming. The first involves constant intake and discharge of water from the ocean or a river in a constant flow system.

The other is a recirculating aquaculture system where the water is purified and not replaced to any great extent.

Developed in Denmark, the recirculating aquaculture system is the newest method. With the closed recycling system, the ocean is not polluted with feed not consumed by the fish and stable production is possible because the system is not affected by natural disasters, such as typhoons.

This type of system is therefore expected to become more popular in the future.

Setsuo Nohara is a pioneer in the development of land-based recirculating aquaculture systems and serves as an Executive Adviser to IMT Engineering as well as a Secretary of Recirculating Aquaculture System Japan.

According to him, this is not the first time a boom has occurred in land-based fish farming.

“The first boom was in the 1980s and the second in the 1990s,” Nohara told The Gas Review.

“Particularly for the second boom, local governing bodies paired up with large companies to undertake business viability projects, but the movement did not spread to general companies.”

“The main reason for the lack of interest was the cost. For land-based fish farming, you’re talking about hundreds of millions of yen, depending on the scale, for all the required facilities, from water tanks and water processing facilities to gas generation equipment.”

“To redeem the expenses, the farmed fish must sell at a reasonable price, but at the same time, cheap Asian farmed fish were being marketing, causing the market price to greatly fall, making any expectations of profit unreasonable.”

“So the companies that participated in the viability projects did not advance into serious commercialisation.”

That said, it is difficult for producers to control the market prices of farmed fish. Therefore, Nohara points out that the best means to promote new entries into land-based fish farming is to lower the cost of equipment to be introduced.

“Oxygen in cylinders or liquid oxygen is over 99% pure and even oxygen from PSA is 90% to 93% pure,” Nohara said.

“However, the oxygen required for fish farming does not have to be that pure. If cheaper oxygen generation equipment can be made available by lowering performance, that would be great.”

Oxygen enrichment increases profitability

Nohara asserts that supplying oxygen is essential to increasing profitability of land-based fiish farming.

“To ensure profit in land-based fish farming, you must perform high-density farming in which at least 3kg of fish is raised for each 1m3 of water.”

“That means a lot more fish than in a natural environment, so it is necessary to introduce oxygen artificially to increase the concentration of dissolved oxygen (DO).”

“However, the amount of oxygen required and the timing of when supplying oxygen is most effective depends on the type of fish.”

“It is rare that land-based fish farmers measure the oxygen concentration daily and understand the optimum supply methods.”

“On the contrary, for companies that handle oxygen gas or oxygen dissolvers, this represents a business chance.”

“If these companies can propose oxyen supply scenarios based on real data on the relationship between oxygen concentration and fish growth, it will greatly lower the hurdle of introducing systems for fish farmers,” Nohara continued.

“Incidentally, water processing facilities also play a vital role in land-based fish farming, just like oxygen supply systems.”

“Particularly for closed recycling systems, where large growth is expected in the future, water processing is the most critical because the same water is recycled for six months to a year while sterilising it.”

“There are several sterilisation methods, such as UV lamps and ozone, but systems are often over-engineered for fish farming or reactions occur with the salt in ocean water creating toxic substances, so there are advantages and disadvantages with each.”

“Industrial gas companies, who lead the gas supply business for fish farming, cooperate with manufacturers of fish farming systems, but we want to involve the water processing facility manufacturers as well.”

“We hope that the new business of land-based fish farming will grow as we gain the cooperation of various industries.”