Traditional Fishing Methods on the Shimanto River
Low-impact traditional fishing methods are still in use on the Shimanto River, helping to preserve its delicate ecosystem and prevent overfishing. The clear waters are rich with algae, which supports a large variety of aquatic life, including ayu (sweetfish), goby, trout, eel, river shrimp and Japanese mitten crab. Different fishing techniques are employed depending on the species and time of year.
Ayu: the sweet prize of the river
Commonly called sweetfish for its fragrant aroma, ayu is a prized catch and a popular summertime food in the area. It is usually lightly salted, skewered, and cooked whole (a method called shioyaki, or salt-grilling.) Ayu have a life span of around one year and hatch in the lower reaches of the river in late fall, before migrating to the sea to feed on plankton. In spring and summer, they return to the river as mature fish and feed on algae in the upper reaches. They move back downstream to the brackish water in fall, to spawn.
Fishing is limited during the ayu lifecycle to conserve the population. The fishing season is open in the summer months to catch mature fish feeding upstream, and in fall when the fish travel downstream to spawn. There are several methods to catch them. Ayu are aggressively territorial and will attack other ayu, so a small live ayu is used as bait to lure larger, stronger sweetfish, in a technique called tomozuri (literally “friend fishing”). As the ayu head upstream, they use their sharp teeth to scrape algae from stones, leaving distinctive patterns, Fishers look for rocks with these patterns, which indicate that the fish are in the area. From late summer to early fall, ayu returning upstream can be caught at night. Using a technique called hiburi-ryo, fishers in boats swing flaming torches in broad circles to drive the fish into nets. In recent years, the torches have been replaced by LED lights, but the original style is sometimes performed for visitors on evening riverboat tours.
Catching eels and shrimp
Eels and river shrimp are caught in traps called korobashi, and floating buoys mark where they have been set up. Eel traps are constructed from long wooden boxes that narrow towards the back and baited with earthworms. For river shrimp, wider tubes with a funnel-like entrance are baited with rice bran.
Another method of catching eels and shrimp relies on their tendency to hide among thick leaves and reeds. Using the shibazuke technique, leafy branches and bundles of leaves are submerged just below the river surface. The eels and shrimp conceal themselves in the leaves and can be scooped up with a large net.
Sustainable fishing methods and limits on fishing seasons for some species ensure that the river will continue to support a healthy and varied population of aquatic life. Traditional fishing methods have a low impact on the water quality and the surrounding environment, helping to conserve the biodiversity of the river and its banks.
