Merwin, of Dorset, Vt., died Wednesday at Dartmouth-Hitchcock Medical Center in Lebanon, N.H.
Veteran fishing editor for Field & Stream magazine, Merwin caught everything from piranhas in the Amazon to Atlantic salmon in Ireland. Among his books are "The New American Trout Fishing" and best-selling "Trailside Guide to Fly Fishing."
Born in Norwalk, Conn., Merwin started fishing with his father at age 3 and never stopped. He moved to Vermont in 1970, and in 1979, out of his basement, launched Rod & Reel magazine (now Fly Rod & Reel). Merwin followed that up with Fly Tackle Dealer, a trade magazine.
The Cremation Society of New Hampshire confirmed Merwin's death.