To study the nymph of the giant salmonfly, Pteronarcys californica, he spent time down in Hole No. 2 of the Madison, breathing through a shower hose. "I found that the Pteronarcys nymphs feed twice every 24 hours," Brooks says. "I'd see them come out from under the rocks where they live to feed on algae on top of the rocks. First the smaller nymphs would come out, then the bigger ones and, finally, the biggest. The fish weren't interested until all the rocks were covered with nymphs of all sizes. Then I tried to find out why the nymphs were feeding when they did. I finally pinned it on temperature. In the summer they like to feed at 58� and generally knock off when it reaches 62�. In the fall, when the water cools, 52� will bring them out to feed."
At times, when a nymph would get washed away from the rocks by the current, a trout would glom on to it. To simulate the nymph in the current, Brooks began fishing what is now known as the Brooks Method. Using a short leader and a high-density sinking-belly line, he casts way upstream and, holding his arms high, allows the nymph to bounce along the bottom in a dead drift.
One autumn several years ago, when the well-known dry-fly fisherman Art Flick visited Brooks to fish the Madison, a cold snap hit. Brooks took the water temperature. It was 46�, and he announced that the fishing wouldn't be good until about 11:30 a.m. Meanwhile he would show Flick how to fish the heavy water with the Brooks Method. Flick got a few strikes, but Brooks explained that these were smaller fish that always began feeding before the bigger fish, in much the same way that the small Pteronarcys nymphs began feeding before the bigger ones did.
At 11:30 Brooks took the temperature, found it was 52� and told Flick the trout would start hitting. They did, right on schedule.
Brooks has been active as the permanent secretary of the Southwestern Montana Fly Fishers, a club he helped found in 1969. Though it has never had more than 24 members, its accomplishments are noteworthy. Its sole objective is to protect, maintain and improve the trout streams of the region. Among the club's achievements: putting an end to the stocking of hatchery trout of catch-able size in streams with naturally producing populations. "When you dump thousands of living units into any area not totally a desert or wilderness, you create an immediate shortage of shelter, and you create an intolerable sociological pressure on those biological units already there," Brooks says. "It does not matter whether we are talking of fish, rats, monkeys or humans. The result is precisely the same: chaos."
Public support for the Southwestern Montana Fly Fishers' goals has become significant. Indeed, last year's closing of the middle Madison to fishing for an undetermined period so that biologists can study the stream won wide public approval. "The swing is our way," says Brooks. "The people here see that they can prosper because people come from all over the country, even the world, to find what they don't have at home, quality fishing in an unspoiled environment." Then he adds, "My energies in life are expended on a narrow plane. I'm involved in studying, writing about, protecting and improving the ecology of trout streams in southwestern Montana. That's it. I'm not out to save the whole world. People who are out to save the whole world don't save anything. But I can say with certainty that the trout fishing we've got, as good as it is, is going to improve even more."