noun
brook trout
Refers to the fish Salvelinus fontinalis, a freshwater salmonid.
カワマスは北米原産の美しい魚です。
The brook trout is a beautiful fish native to North America.
この川ではカワマスが釣れます。
You can catch brook trout in this river.
Compound of 川 (kawa, 'river') and 鱒 (masu, 'trout'), literally 'river trout'.