Some of the smaller rivers and streams are closed to all fishing until the late May opening to allow the Rainbows and Cutthroats to spawn and not be disturbed. By late May that is all over with and the fish are heading back to the larger rivers to bulk up again. Other rivers are open for catch and release only until late May, then depending upon the river some fish can be kept, either based on number of fish, slot sizes or species. Montana is very protective of their Cutthroats and Bull Trout. Larry ---sagefisher---