Carl Linnaeus, The Lapland Journey, translated by Peter Graves (Edinburgh: Lockharton Press, 1995), p. 32.

Uppland, 13/05/1732, ¶47:

These falls drop over a cliff of black bedrock which it is impossible to examine more closely. Downstream from the falls, after the water in the channels has become a little calmer, there is a salmon fishery with a square wickerwork enclosure which projects 2 feet above the water. The salmon enter this and cannot get out.