This section is from the book "American Game Fishes", by W. A. Perry. Also available from Amazon: American Game Fishes: Their Habits, Habitat, and Peculiarities; How, When, and Where to Angle for Them.
"Within a short distance (soon walked) from the hotel, the three rivers above named-Gallatin, Madison and Jefferson-flow close together and are indiscriminately fished by the resident anglers. In all the rivers the Grayling, the Rocky Mountain Trout (Salvelinus purpuratus~) and White-fish (Coregonas williamsonii) can be found, but the Gallatin is the fish river of my dreams. In its waters the three fish, just named, veritably 'swarm.'
"We fished the Gallatin at a point about four miles from the town, and as I descended the bank to reach the stream, the surface of the pool before me was mottled with jumping and feeding fish. Here a Grayling, there a Trout, and in between, a White-fish. It seemed a sacrilege to the memory of Brother Izaak to place a lure before them. Stifling our qualms (easily done) we walked above the pool and cast our two flies at the lower end of the incoming rapid. Two fish, of course-one a Grayling, the other a Whitensh; the first on a brown hackle, the latter on a coachman. Again a cast, again two fish, and so on for a half-hour, alternating in species between the Trout, the Grayling, and the Whitefish.
"I did not move more than ten yards from my first position during the half-hour, at the end of which I became sated and started up-stream to fish the unlikely places, recalling to mind a similar experience on my first visit to the Gogebic Bass, when, to the surprise of my guide, I told him to take me to some place where the fish were not so plentiful. This satiated cry-'enough,' 'enough'-is doubtless a personal experience with many of my readers and it is the sign manual that distinguishes the angler from the pot-fisher.
"The Grayling of Montana, to catch which I had traveled more than 2,000 miles, did not disappoint my angling expectations. It is, I think, a stronger fish, with sturdier fighting qualities, than its congener of Michigan waters. It has a thicker, broader body, and a somewhat longer head, but is much less beautiful in contour and coloration. The Eastern fish is more clipper-built, leaping frequently from the water when hooked; in fact reminding me, measurably of course, of the Skip-jack or Lady-fish of Florida, which is almost constantly out of the water 'dancing on its tail,' when you are bringing it to creel. The leap of the Montana Grayling is not frequent, as the fish is disposed to fight deep, making longer and stronger surges under the restraint of the tackle, than those of Michigan waters. The coloration of the two fish differs: the violet bloom of the body, seemingly translucent, is of a more delicate tint in the Eastern fish and more generally diffused. The dorsal fin, from which the Graylings derive their specific name-signifcr, 'the standard bearer' - is not so high or so resplendently colored as those of the Michigan fish.
"Two striking differences exist between the habits and habitat of the Montana and Michigan Graylings. The latter lives and thrives only in rivers, spring-fed, with sandy bottoms, and of a temperature seldom exceeding fifty-two degrees. Our recollection of the Manistee in Michigan, upon which we spent several days among the Grayling two years ago, is that we did not see even a pebble upon the bottom, except, here and there, a small cluster of stones not much larger than hen-eggs, which were exposed on the rapids by the rapid rush of the stream, and these stony rifts were of small dimensions, and often a mile or two distant from each other. The rest of the stream consisted of shallow, sandy reaches and pools, at the bottom of which the sand was mottled with patches of white and yellow with dark blotches here and there, formed by a deposit of drift. In the Gallatin the conditions are reversed. The temperature often reaches sixty degrees, and the bed of the river is for the most part rocky, at least, covered with stones, the smallest of which may be represented by the cobble-stones of street pavements. In truth, the pool above referred to, in which I caught most of my Grayling, was rough-strewn with rocks, many of which sized up to that of a bushel measure; a sandy reach was not seen along the two miles of the stream fished by our party.
"Again--It is an established fact that the Michigan Grayling cannot live and increase in any stream in which trout or other fish have established themselves. They seem to diminish very rapidly under such conditions, and, strange to say, the reverse is the fact in English waters, where Thymallus holds its own against the brown Trout. In the Gallatin, the Trout, the Grayling and the Whitefish live in harmonious brotherhood. On one occasion, using three flies as an experiment, I caught one of each of these three fish, at the same cast, showing that they feed and range together.
"The ordinary Trout-flies used in the East will, under favorable conditions, lure the Grayling, the Trout and the Whitefish, of Montana waters. The hackles, black, brown and gray, should always be in stock, and of the winged flies, the Professor, Lord Baltimore, Abbey, Yellow Sally, Montreal, etc., are useful."
The number of anglers at the Gallatin increases rapidly, and a very few years may serve to throw light upon the question whether the Trout or the fishermen are to be held responsible for the dearth of Grayling in their former favorite haunts.
The proper tackle for Grayling is the same as that used for Trout: a light rod, click-reel, and twenty-five or thirty yards of water-proofed line. The weight of the rod may depend upon the swiftness of the current to be fished. If this is not too rapid, a rod of four to six ounces will land the largest Grayling in Michigan or Montana waters.
Generally speaking, however, an eight-ounce rod is not too heavy, and will be found more satisfactory for all waters. The Grayling can fight hard when he chooses. I have seen a pretty good rod broken at the handle by a bait-fisher, in trying to throw out a large Grayling by main strength. Nevertheless, in fishing for the Grayling, do not forget, particularly if you are a Trout-fisher, that it has a very tender mouth, much more so than the Trout, and must be dealt with accordingly.