The Fish of Lake Chuzenji
Lake Chuzenji is a mecca for sportfishing, and the fish that lure anglers include masu salmon, white-spotted char, brook trout, lake trout, and rainbow trout. It has the highest elevation of any major lake in Japan but had no fish at all until a little over a century ago.
Around 20,000 years ago, volcanic activity at Mt. Nantai blocked and diverted rivers, creating the lake and the steep waterfalls of Okunikko, or inner Nikko. Originally, there were no fish in the waters that flowed into the lake from the northwest, and the 97-meter-tall Kegon Falls prevents fish from swimming up the Daiya River into the lake from farther downstream.
From the late eighth century, the mountains of Okunikko were an important center for ascetic religious practices, and there were many religious restrictions in the area until 1871. The stocking of fish in the lake began in 1873 when char raised in the Okunikko area were released. In 1874, common carp, crucian carp, eel, and loach were added. Whitefish were introduced from Russia in 1881, followed by domestic fish from Lake Biwa and Hokkaido, including trout, salmon, and minnow.
Thomas Glover (1838–1911), Scottish merchant, fly-fishing enthusiast, and longtime resident of Japan, was instrumental in stocking the lake with fish suitable for sportfishing. He financed the importation of brook trout from Colorado in 1902 and 1904.