Even properly released fish might die. Stress during the battle can weaken and subsequently kill fish. According to Dick Oswald, a biologist for the Montana Department of Fish, Wildlife and Parks, elevated water temperatures because of low flows are critical to trout. In Montana's legendary Big Hole River, for example, when the water temperature reaches the high 60s, even properly released fish will quickly die. In a recent article in the Billings Gazette, Oswald said fishermen have complained about large numbers of dead trout along the banks of popular angling spots, the fish having died after being released. When these conditions occur, voluntary restraint is usually called for, though the river was completely closed to fishing during the severe droughts of 2000 and 2001.