Seki aji horse mackerel

The Hayasui Strait lies between Oita’s Saganoseki Peninsula and Ehime’s Cape Sada. Its fast current, uneven seabed, and rich feed are tied to horse mackerel with firm flesh and moderate fat. The local character of Seki aji is concrete: it rests on this water, the Saganoseki landing place, and the way the fish is handled after it is caught.

Seki aji is caught by fishers of the Oita fisheries cooperative’s Saganoseki branch using single-line fishing. Each fish is brought aboard and placed in a live tank, then carried back to the harbor alive. From the Hayasui Strait to Saganoseki port, the handling aims to avoid bruising and preserve the fish’s condition before the next steps begin.

At the harbor, buyers use tsuragai, judging size and quality while the fish remain visible from the water surface. This avoids the damage that can happen when a live fish struggles on a scale. After that judgment, the fish move into dedicated holding tanks, so human observation, harbor equipment, and protection of the flesh all belong to the same process.

Before the fish leaves the harbor process, each Seki aji is handled by ikejime and nerve removal. These hand-performed steps are used to keep freshness and support the firm bite expected in sashimi. A handling facility completed in 2012 added sterilized seawater and slurry ice made with that seawater, giving the harbor work a cleaner and more controlled setting.

The best-known season for Seki aji runs from July to September, while the cooperative also lists a March-to-October fishing period. In sashimi, the firm flesh and balanced fat become easy to notice. A squeeze of Oita kabosu sharpens the umami, linking the fish, the citrus, and a summer meal from Saganoseki in one plate.

The name Seki aji points to horse mackerel from the Hayasui Strait off Saganoseki, landed at Saganoseki, caught by single-line fishing, and handled by the Saganoseki branch community. A regional collective trademark stands behind that name protection; for readers, its practical meaning is the boundary around water, method, harbor, and fishing community, rather than a label that any horse mackerel can carry.