TOKYO - Japan’s beloved seafood is now in crisis. Compared to five years ago, catches of Pacific saury have dropped by 80%, Japanese flying squid by 55.5%, mackerel by 50%, and yellowtail by 13%.
According to Yokotsuka, the mackerel situation is dire. “Whether it’s saury, squid, or yellowtail, the numbers have plummeted compared to five years ago,” he said. Upon closer investigation, it turns out mackerel is at the heart of the crisis—so much so that it’s being dubbed the “mackerel shock.” The impact is being felt nationwide, including in Osaka.
Yokotsuka spoke with the president of a major seafood chain, who said the situation is worse now than it was 20 years ago. These days, the company has to constantly chase real-time information from production regions across Japan to secure supplies. While they’ve always been committed to domestic mackerel, they’ve now started importing from Norway as well. “Norwegian mackerel is tasty and large, but it’s not quite the same,” he noted.
This is part of a vicious cycle. One of the key drivers is climate change. Warmer ocean currents, such as the Kuroshio, which used to run from the waters off Kyushu and Shikoku up to Chiba’s Boso Peninsula, have shifted. The comfortable habitat for mackerel, which used to be in waters off the Sanriku region and further south, has now moved northward.
Plankton—essential food for mackerel—also used to be abundant in these southern waters. However, rising sea temperatures have pushed them north. This forces the mackerel to follow their food, migrating toward the northern seas, even into the waters around the Kuril Islands.
This creates serious challenges for Japanese fishermen, whose traditional fishing grounds have moved farther away. Many fishing vessels are not equipped to go that far, making it harder to catch fresh fish.
Even as the mackerel try to follow the plankton north, the colder temperatures in those waters exceed their tolerance, leaving them unable to thrive or feed properly. As a result, there’s less nourishment in their current habitats.
This has led to slower growth: mackerel that used to mature into adults in two years now take four years. Because of this, fishermen often catch juveniles before they can reproduce, further reducing the population.
The reduction in plankton is also part of a larger environmental trend. As the seas warm, the nutrient content in these waters declines, leaving fish malnourished and underweight. This is affecting a wide range of marine life in the region.
While there are efforts to breed mackerel in captivity, progress remains limited. Mackerel are highly sensitive to light and sound, and easily become startled, which often results in injuries or broken bones—making aquaculture difficult.
They are also fast swimmers, reaching speeds of up to 50 km/h, which makes them hard to contain. Still, research and trials continue.
One example is the brand-name “Bōze Mackerel” farmed in the calm waters near Himeji’s Ieshima Islands in the Seto Inland Sea. Thanks to controlled feeding and water conditions, this mackerel is suitable for sashimi and hot pot dishes—an uncommon luxury.
Another example is “Tottori Saba-chan,” a land-based farmed mackerel raised using underground seawater with stable temperatures. These fish are fed a rich diet of white squid, red flatfish, rock oysters, and even yuzu, resulting in a delicate fragrance and refined flavor.
Such efforts aim to brand and add value to farmed mackerel. While prices are not yet finalized, land-based aquaculture is beginning to supply these fish to retail markets as well.
Still, at present, natural catches remain essential. While aquaculture continues to advance, for the time being, we may have to rely on the mackerel that’s still available—however scarce it may be.
Source: YOMIURI
