Nippon Suisan Kaisha Ltd., Yumigahama Suisan Co., Ltd. of the Nissui Group, and Hitachi Zosen Corporation are working together to commercialize a land-based recirculating aquaculture system (RAS) to raise chub mackerel.
The companies reached an agreement for the joint development of a test facility located in Yonago City, Tottori Prefecture, in Feburary 2019. Construction commenced in June of 2019, and the facility was placed in operation in April 2020. The test development period is set to run until the end of March 2023, and commercialization is planned from the following month. When fully up and running, it will be the first large-scale land-based RAS for chub mackerel (Scomber japonicus) in Japan. Expected production totals were not announced.
Yumigahama Suisan Co., Ltd. is already farming salmon, and has been cooperating in various tests to advance technology in aquaculture, while Hitachi Zosen – which engineers and builds various industrial facilities – is experienced in water treatment technology.
Before the test facility can successfully reach full commercialization, it must overcome several technological issues before production can be scaled up.
Solids – such as uneaten feed and fish feces – deteriorate the quality of water in the rearing tanks. Ammonia from the fish feces and uneaten feed must be quickly decomposed and removed, as it is toxic to fish.
Hitachi Zosen’s computer simulation technology of the movement of fluids will be used to improve the efficiency of removing these solids, and a nitrification treatment system developed by the company – using free-floating filters – is expected to make the nitrification facility more compact, and reduce initial costs.
Electricity is also a major cost for land-based systems. Through the test project, the companies plan to develop efficient operating methods and adopt operation controls that reduce electricity and other running costs.
Through the testing, the facility will also identify optimal rearing conditions for the fish, including water temperature, water quality, water flow, and the period of exposure to light to reach a high level of aquaculture productivity.
Making sure running costs for the facility are low is important, given the lower cost of the species. The typical price of fresh chub mackerel at Tokyo’s Toyosu wholesale market on 26 January ranged from JPY 216 to JPY 540 (USD 2.08 to USD 5.20, EUR 1.71 to EUR 5.29) per kilogram. That’s far less than that of another species that is commonly tank-raised in South Korea and Japan – olive flounder (Paralichthys olivaceus) – which traded in the range of JPY 540 to JPY 1,944 (USD 5.20 USD 18.73, EUR 5.29 EUR 15.43) per kilogram.
However, mackerel could be used as a model animal for studying how to manipulate puberty in Pacific bluefin tuna, or could be used via implanted bluefin gonads to spawn tuna from mackerel parents. Work by Japanese scientist Goro Yamazaki has shown that mackerel can be used as surrogate parents of bluefin by transplanting tuna reproductive stem cells into mackerel fry. The mackerel then produce tuna sperm and eggs. The much smaller mackerel mature faster, and are less expensive to feed and maintain.
Photo courtesy of Nissui/Hitachi Zosen
