Western Maine is a land of deep forests, mysterious bogs, and wide lakes. Its rivers are unrestrained, as wild as the moose along their shores, with rapids willing to sweep an unsuspecting angler off his or her feet and moods that change as quickly as a salmon slips a hook. Dark pools hold char, commonly known as brook trout, called speckled trout or squaretails by old-timers, fish so large they’ll steal an angler’s breath away.

Palm-sized brook trout, as bright as a handful of marbles and as...