Ayu, sweetfish あゆ、鮎
(Plecoglossus altivelis)
Popular freshwater fish. Both caught and farmed in mountain streams. Can grow up to 30 cm in length, but the usual size is about 15 cm.
The food of this herbivorous river fish consists of algae. They have a very long intestine for digestion.
The main methods for catching ayu are by means of fly fishing, by using
a fish trap, and by fishing with a decoy which is known as
"ayu-no-tomozuri" in Japan. The decoy is a living ayu placed on a hook,
which swims when immersed into the water. It provokes the territorial
behavior of other ayu, which assault the "intruder" and then get caught. Ayu is also fished commercially, and captive juveniles are raised in
aquaculture before being released into rivers for sport fishing.
A very romantic way to catch ayu is with trained cormorants and flares at night. The fishermen work from shallow, wooden boats and each of them leads about a dozen cormorants on leashes which swim
alongside the boat and dive under the water to catch ayu by swallowing
them whole. The
bird stores the fish in its crop, and delivers it later to the
fisherman (the catch is prevented from being swallowed by a snare around the bird's neck). After that the catch goes via the grill straight into the mouths of the eaters. Cormorant fishing (ukai) is practiced on the Nagaragawa River, Gifu City (May 11 to October 15), on the Hozu River, Arashiyama-Kyoto (July 1 to September 23) and the Uji River, Uji (July to September). These events are popular with tourists from all over the world and special sightseeing courses are offered.
But these are rare, touristic events. Most ayu are caught by rod and line, or trapped as indicated in the above, by sport fishermen.
[Salt-grilled ayu]
The white flesh of ayu has a delicate, somewhat sweet flavor with "melon and cucumber aromas." It is consequently highly prized as a food fish.
Ayu is usually sprinkled with salt and grilled whole (shioyaki). The best season (shun) is summer and autumn. The late season fish, ochiayu, heavy with roe, is especially prized. Ayu are not cleaned, but eaten whole. A common method of preparing ayu in Japan is to skewer it in such a way that its body forms a wave, making it look as though it is swimming.
Photos from Wikimedia Commons
Japanese Food Dictionary