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In Takashima, Nagasaki City, a challenge has begun to fully cultivate this “phantom” high-grade fish. “It looks quite tough, but it has a very delicate heart,” says the Japanese sea bass, a type of sea bass. “It’s quite timid, and when people come near, it tries to hide behind something… That’s also quite cute.”
Takashima, Nagasaki City, is a small island with a population of about 200 people, a 30-minute boat ride from Nagasaki Port. Japanese sea bass are said to inhabit the waters around Takashima during the winter (December to January). It is a “phantom” fish known only to fishermen.
Japanese sea bass fishing has been thriving in Takashima since ancient times. What kind of fish is the Japanese sea bass? Makoto Hamasaki (45), a fisherman with 14 years of experience: “I think everyone is more familiar with the Japanese sea bass. Generally speaking, when we ship flathead sea bass to the fish market, it sells for 2,000 yen per kilogram, but Japanese sea bass sells for 500 yen per kilogram, about four times as much. Personally, I think flathead sea bass has a refined and slightly mild flavor. Flathead sea bass has a concentrated umami flavor.” Its personality is “quite timid.” The strong wariness of the flathead sea bass is hindering a world first. Now, Takashima is moving towards complete aquaculture of this high-class fish that it is proud of, without relying on natural resources.
Toshiaki Fujikawa, Specially Appointed Researcher at Nagasaki University’s Institute for Marine Future Innovation: “This is where our BLUE Economy project will be conducted. We will be raising six species of fish: yellowtail, red grouper, goby, gizzard shad, Japanese whiting, and Japanese sea bass.” Nagasaki University’s Institute for Marine Future Innovation began research on Japanese sea bass last year as part of the Japan Science and Technology Agency’s “Nagasaki BLUE Economy” project, which aims for complete aquaculture. The research was entrusted to Toshiaki Fujikawa, a specially appointed researcher with 10 years of experience in fish research. In April of last year, they attempted to induce spawning from 11 Japanese sea bass given to them by local fishermen.
Minoru Fujikawa, Specially Appointed Researcher at Nagasaki University’s Institute for Marine Future Innovation: “Initially, we thought we could collect eggs from these fish, so we tried to produce seedlings and start aquaculture, but the eggs didn’t come out when the time came. When they lay eggs, they go to specific areas or engage in specific behaviors. We have absolutely no idea about this for the Japanese sea bass.” There are still no successful examples of complete aquaculture of Japanese sea bass in the world. What is the suitable environment for spawning? What is their preferred food? Even though everything is unknown, some things have been learned.
Toshiaki Fujikawa, Specially Appointed Researcher at Nagasaki University’s Institute for Marine Future Innovation: “Among the fish species we keep here, the Japanese sea bass are quite wary and tend to hide in the shadows. They’re quite timid, and if you disturb them too much, they stop eating well, so they’re nervous fish that require careful handling.” From 20,000 to 100… Plankton saved them from a drastic decline. Giving up on natural spawning, artificial insemination was performed in January of this year, and they succeeded in securing 280,000 fertilized eggs. From there, it was two nights and nights. A period of staring intently at the eggs continued.
Toshiaki Fujikawa, Specially Appointed Researcher at Nagasaki University’s Institute for Marine Future Innovation: “Eyes started to form, muscles developed, and their hearts began to beat. I was excited, thinking that they would hatch properly. This moment was so joyful, and as I watched, I could see them twisting their bodies inside the eggs, thinking, ‘Just a little longer, just a little longer.'” 20,000 eggs successfully hatched. However, the joy was short-lived. Three months later, during the growth process, their numbers plummet to just 100.
Through extensive research, Mr. Fujikawa discovered that the cause lies in their “food.” Minoru Fujikawa, Specially Appointed Researcher at Nagasaki University’s Institute for Marine Future Innovation: “These compound feeds are man-made feeds. We tried switching to a finer type of feed. It makes management easier and has high nutritional value. However, although they ate it, they lost weight at an incredible rate. We realized this was a problem, so we fed them frozen zooplankton and managed to keep 100 of them alive.”
What he learned from the failure: Minoru Fujikawa, Specially Appointed Researcher at Nagasaki University’s Institute for Marine Future Innovation: “It seems that the necessary nutritional components are different. Probably different. We still don’t understand that at all, but I think they might be lacking something in the taurine family (a type of amino acid), so in the next experiment we will try feeding them a feed with different components.” Three years until they lay eggs, the dream of the world’s first “complete aquaculture” is entrusted to the 100 surviving fish. Fujikawa is completely captivated by the mysterious Japanese sea bass. Minoru Fujikawa, Specially Appointed Researcher at Nagasaki University’s Institute for Marine Future Innovation: “They have big, darting eyes, and they’re so cute, aren’t they?” It’s said that it will take at least three years for these 100 sea bass to grow to adult size a
nd lay eggs. What is Fujikawa aiming for beyond that? Minoru Fujikawa, Specially Appointed Researcher at Nagasaki University’s Institute for Marine Future Innovation: “If we can promote these sea bass as a farmed fish in Nagasaki, I want people all over the country to taste this legendary fish. It’s delicious, you know. It’s delicious, so I’ll do my best to make it happen.” Towards the world’s first successful complete aquaculture—to create a new industry in Takashima, the young researcher is casting an enthusiastic gaze on the slightly shy sea bass.
