YELLOWSTONE Fishes of the Yellowstone National Park

1. MONTANA GRAYLING (Thymallus montanus).

The Montana grayling, which originally existed only in tributaries of the Missouri River above Great Falls, in the park occurs naturally in the Madison and Gallatin Rivers and their branches, Grayling Creek and Fan Creek, and in the Firehole River below the falls. It is reported as sometimes abundant at the junction of the Gibbon and Firehole Rivers and is said to ascend in summer as far as Firehole Falls. It is the principal fish in the south fork of the Madison and occurs also in the backwater of the Madison at the dam. This is a most graceful and attractive fish, of shapely proportions and exquisite coloration. The adult averages about 1 pound, but may attain a weight of 4 pounds.

The grayling prefers swift, clear, pure streams, with gravelly or sandy bottom. It is quite gregarious, lying in schools in the deeper pools, in plain sight, and not, like the trout, concealed under bushes and overhanging banks. In search of food, which consists principally of insects and their larvae, it occasionally extends its range to streams strewn with bowlders and broken rocks.

Unlike the native trout, the grayling will go long distances, if necessary, to find suitable spawning grounds. It spawns in April and May on gravelly shallows. In the north fork of the Madison River, where the water is comparatively warm, coming from the Firehole River in the park, the grayling spawns a month earlier than in any other waters in Montana.

In point of activity it even excels the native trout, when hooked breaking the water repeatedly in its effort to escape, which the trout seldom does. It takes the artificial fly eagerly, and if missed at the first cast will rise again and again from the depths of the pool, whereas the trout will seldom rise a second time without a rest. It will also take various baits, such as caddis-fly larvae, grasshoppers, and worms. Among the recommended flies are professor, Lord Baltimore, queen of the water, grizzly king, Henshall, coachman, and various gauze-winged flies, with No. 10 and 12 hooks. As a food fish it is even better than the trout, its flesh being firm and flaky, very white, and of delicate flavor. The grayling is artificially propagated in Montana by the United States Bureau of Fisheries and the State fish commission.

FIG. 1.—Montana grayling.

2. ROCKY MOUNTAIN WHITEFISH (Coregonus williamsoni).

The Rocky Mountain whitefish occurs in all suitable waters on the west slope of the Rockies from Utah to British Columbia. A scarcely, if at all, distinguishable variety or subspecies bearing the name of Coregonus williamsoni cismontanus is found in certain waters of the upper Missouri Basin. In some localities this fish is miscalled grayling,⁴ with which it should not be confused, as it is a very different species, and there seems to be a local Yellowstone River name, the phonetic spelling of which is "sterlet" or "steret."

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⁴Referring to the fishing in the canyon of Sunlight Creek, Clark Fork, Ralph E. Clark probably made this mistake in writing the following: "You will probably first catch a scaly fish which looks like a long sucker. It is the Montana grayling, and there are many down there."

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In the park it naturally occurs in the Yellowstone River below the falls as far up as Crevice Gulch, beyond which it is seldom found, in Madison and Gallatin Rivers below the falls, and has been reported also from the junction of Firehole and Gibbon Rivers. At the junction of Lewis and Snake Rivers "grayling," or "mountain herring," are reported as taken by anglers; these are doubtless whitefish.

Young whitefish 2 to 5 inches long from Montana were planted in park waters, as follows: In 1889, 2,000 were placed in Twin Lakes and 980 in Yellowstone River above the falls, and 10,000 more were planted in the latter place in 1890. It is considered doubtful if any of these have survived, owing to the number and size of voracious trout in the Yellowstone River and the mineral character and high temperature of Twin Lakes.

This fish prefers clear, cold lakes and streams, where the usual length of adults is about a foot, although it is known to have attained a weight of 4 pounds. The cismontanus form is essentially a river fish rather than an inhabitant of lakes and is most abundant in the eddies or deeper places of swift streams. It spawns in late fall or early winter. This is a slender, graceful fish, readily taking the artificial fly like a grayling or trout, as well as natural baits, such as worms and insects and even fresh meat. However, owing to the smallness of its mouth, the hook should be no larger than No. 10 or 12, and when hooked the fish requires careful "playing" owing to the tenderness of the mouth parts. It is a game fighter. It ranks high as a panfish, for, when in condition, it is of surpassing sweetness and delicacy of flavor.

FIG. 2—Rocky Mountain whitefish.

3. REDTHROAT TROUT: CUTTHROAT TROUT; BLACKSPOTTED TROUT (Salmo lewisi).

In its numerous varietal, subspecific, or specific forms the red throat, cutthroat, or blackspotted trout is of extensive distribution on the Pacific slope. In the park a form designated as Salmo lewisi is found naturally in both upper Snake and upper Missouri waters, having doubtless gained access to the latter from the Snake River by the way of Two Ocean Pass, and it is not unlikely that an interchange of individuals still takes place.

Yellowstone Lake and Yellowstone River from its source to many miles beyond the park are inhabited by it. The abundance of trout above the falls is remarkable. At almost any time as one passes along fish are seen breaking water.

Trout are known to naturally occur in the following park waters:

Gibbon River has no trout above the falls. In the Firehole River trout occur naturally below the falls. At times near the junction with the Madison there is very good fishing.

In the Gardiner River trout are abundant from the foot of the falls to its junction with the Yellowstone. Trout have not been seen above Osprey Falls.

In Soda Butte Creek trout are numerous until obstructed by falls in the upper part.

Hellroaring Creek is well stocked in the lower part.

In Canyon Creek trout abound below the falls.

It is stated on good authority that, notwithstanding the barrier offered by Undine Falls, trout occur above in Lupine and Lava Creeks. It appears that in 1889 trout obtained from Howard Creek, Idaho, were planted in Lava Creek. However, it was subsequently ascertained that trout had possible access to this locality from Blacktail Deer Creek, which has no falls and was abundantly supplied with trout.

Trout are numerous in Heart Lake and, according to A. H. Dinsmore, in Lewis River below the falls.

The size attained by trout in the park waters, as elsewhere, varies much with locality and conditions. Fish of over 4 pounds have been reported.

This trout in some waters is a highly esteemed game fish and can be taken in all sorts of ways—spoon, phantom, natural bait, artificial fly, etc. Mary Trowbridge Townsend (l. c.) writes of it in the Firehole River:

The father of the Pacific trout, the blackspotted "cutthroat" with the scarlet splotch on his lower jaw, was most in evidence, with long symmetrical body, graduated black spots on his burnished sides. He is a brave, dashing fighter, often leaping salmon-like many times from the water before he can be brought to creel. We found him feeding on the open riffs or rising on the clear surface of some sunlit pool.

Ralph E. Clark Wrote (l. c.) that "the dark, silvergray trout of the West seem to favor flies more in harmony with their own coloring," and mentioned the gray hackle, brown hackle, coachman, grizzly king, Seth Green, black gnat, and white moth:

The junction of Yellowstone and Lamar Rivers is noted for fine fishing. If you find the waters high, swift, and roily, you will probably try your flies in vain. Put on a spinner or a little spoon and watch the fish rise to it, almost touch it, and then go away. They are after live bait and won't touch anything else. The grasshoppers are abundant. Catch a few, bait your hook carefully, and let it float down with the current. A large trout will rise to it, and if you are not very careful he will steal it from you.

This is an excellent food fish when fresh from cool waters, but the trout from some parts of the Yellowstone Lake, Upper Yellowstone River, and Heart Lake are generally reputed to be infested with a parasitic worm. In his book previously cited in the list of publications pertaining to the fish of the park, Gen. Chittenden says:

The trout of Yellowstone Lake are to a slight degree infected with a parasitic disease that renders them unfit for eating. Many efforts have been made to discover the cause of this condition and a suitable remedy for it, but so far without success. An explanation sometimes advanced is that the excessive number of these fish and the absence of sufficient food reduce the vitality and they become an easy prey to parasites which a more vigorous coastitution would throw off. Later investigations have shown that reports of the prevalence of this condition were much exaggerated.

The parasite referred to is a tapeworm, of which only the larval or intermediate form occurs in the trout, the host of the adult being an entirely different animal, as is the case with all tapeworms of this kind. Briefly, its life cycle has been found to be as follows: Starting with the egg in the water, it develops into a ciliated embryo. This passes into the fish, probably by way of the mouth, and becomes established and assumes the form usually observed. The fish is eaten by the pelican, and in the intestinal tract of that bird the parasite attains its adult and reproductive stage, and its round of life is there completed. The eggs pass into the water and a new generation is begun.

Gen. Chittenden's statement that the parasite renders the fish unfit for food involves a matter of prejudice rather than actual unfitness for food or danger to the consumer. Cooking destroys the vitality of the worm, and it may be said that this particular worm is not harmful to man. Probably no one would knowingly eat an infected fish, but if he should there would be absolutely no danger in doing so. Beyond doubt the presence of this parasite is greatly exaggerated, as Gen. Chittenden says, and lean, cadaverous, unsightly trout, the condition of which is commonly attributed to parasitism, are often fish which are run down from breeding, although they may carry some parasites. There is scarcely a fish that swims that is not more or less infected by some sort of parasitic worm, and in this respect the Yellowstone fish do not appear to be worse than fish of many other lakes in the country.

It has been said that there are two varieties of native trout in the park, the larger ones of the Yellowstone, with bright yellow bellies, and the smaller kind more silvery in appearance and exhibiting much greater activity and game qualities, of which Tower Creek fish are examples. Also trout of Yellowstone Lake seem to differ from those of Heart and Henry Lakes in having more distinct and rather less numerous black spots. However, in this respect very much individual variation is shown.

This is the principal fish artificially propagated by the United States Bureau of Fisheries at the hatcheries on Yellowstone Lake and Soda Butte Creek. From three to twenty million eggs are taken annually. After the local park waters are liberally stocked the remaIning young are supplied to suitable waters in the adjoining States. The park, however, should and does have the first and major claim on the hatchery output.

FIG. 3.—Redthroat trout; Cutthroat trout; Blackspotted trout.

4. RAINBOW TROUT (Salmo shasta).

The rainbow trout has its geographical range in the mountain streams of the Coast Range and the western slopes of the Sierra Nevada Mountains, but the natural abode of the rainbow trout of fish-cultural fame is the McCloud River, Calif. This form, now recognized as a species distinct from Salmo irideus, bears the name of Salmo shasta. It has been successfully introduced into many streams in different parts of the United States where it was not previously found.

The rainbow, first introduced into the park in the Gibbon River in 1880 and subsequently planted in various waters and on numerous occasions, has become one of the most abundant, most widely distributed, and most popular of the park fishes. The waters stocked, in addition to the Gibbon River above and below the falls, have included the Gardiner River, tributaries of Yellowstone Lake, and various small lakes.

The size attained by the rainbow trout varies greatly and is dependent upon volume of water, temperature, food supply, etc. Under certain conditions it reaches an extraordinary size, but in the ordinary environment 6-pound or 8-pound fish are to be regarded as large. In general, it may be said that the fish does not overrun 2 pounds. Its food is composed largely of insects.

This fish now abounds in the Gibbon River both above and below Virginia Cascades, and good fishing is found at times at the junction with the Madison. Regarding this stream the park superintendent's report for 1897 shows that the fish planted above the cascades seemed to have come down over the falls, as but few were found above, while below the stream was well stocked to its junction with the Firehole. In the Gibbon River above the falls it appears that the supply has been greatly depleted, in fact, nearly fished out, owing to the circumstance that the road follows the stream for many miles, and there must have been thousands of anglers fishing there in 1919, according to the senior author's notes of July, 1919. Grebe Lake, Blacktail Deer Creek, Madison, Firehole, and Little Firehole Rivers all contain rainbow trout. Referring to the last-named stream in 1897, the superintendent of the park wrote that several good specimens had been taken near its source, for which he could not account, as it seemed impossible for any fish to ascend the lower falls of the Little Firehole. A. H. Dinsmore reports the fish from Tower Creek above the falls.

Many persons who have had experience in angling for rainbow trout say it is one of the best, and some pronounce it the very best, of the trouts. It often dashes from the water to meet the descending fly and leaps repeatedly and madly when hooked. It has been said that it takes the fly so readily that there is no reason for resorting to other lures. However, its activity and habits, as in the case of most fishes, are modified more or less by its surrounding conditions. The same is true of its food qualities, which ordinarily are very good.

Mary Trowbridge Townsend (l. c.) had the following to say relative to her experience with the rainbow trout in Firehole River:

The California rainbow trout proved true to his reputation as absolutely eccentric and uncertain, sometimes greedily taking a fly and again refusing to be tempted by the most brilliant array of a carefully stocked book. During several days' fishing we landed some small ones, none weighing over 2 pounds, although they are said to have outstripped the other varieties in rapidity of growth, and tales were told of 4-pounders landed by more favored anglers.

FIG. 4—Rainbow trout.

5. SCOTCH LAKE TROUT; LOCH LEVEN TROUT (Salmo levenensis).

This trout originated in Loch Leven, the lake made famous by Scott's poem, "The Lady of the Lake." Typically it was peculiar to this loch, where it seldom if ever attained much over 1 pound in weight. The claim has been made that it is merely an ontogenetic development of the common brown trout, and that when transferred to other waters its progeny can not always be distinguished from the common brown trout. On the other hand, information derived from persons familiar with Loch Leven indicates that both this trout and the brown trout exist in the same lake, and that in that body of water they can always be distinguished.

It is not impossible that confusion has arisen by brown trout from that lake having been propagated under the supposition that they were Loch Leven trout. There are parallel instances of such mistaken identity in this country in respect to other species, and so-called Loch Leven trout have been propagated for a long time in this country. In the early years the progeny of Loch Leven eggs could easily be distinguished from brown trout hatched at the same time, especially when they had attained a few inches in length. Recently, however, there is reason to suspect that many of the so-called Loch Leven plants have been brown trout. Be that as it may, trout under each name have been introduced into Yellowstone Park waters, and there are records of both having been subsequently taken. The first plants of this trout in the park were made in the upper part of the Firehole River in 1889. The next year Lewis Lake and Shoshone Lake were stocked, and in 1903 further plants were made in tributaries of the Firehole.

The Loch Leven trout has been taken in the following park waters, in some of which it is abundant: Firehole River above and below the cascades, Madison, Gibbon, and Gardiner Rivers, Shoshone and Lewis Lakes and the "canal" connecting those lakes, upper Snake River waters, Heron Creek, and Duck Lake, near the Thumb of Yellowstone Lake.

Fish of large size and in great abundance were found in Duck Lake in 1919. Landlocked salmon had been planted in this lake in 1908 and were reported to have survived an flourished, but none have ever been authentically identified, and it seems likely that the Loch Leven trout, the history of whose introduction into this lake is quite obscure, have been mistaken for landlocked salmon. Hundreds of fish were observed jumping at times, and a number of specimens up to 4 pounds in weight were taken in the summer of 1919 after a game fight.

FIG. 5.—Scotch lake trout; Loch Leven trout.

6. EUROPEAN BROWN TROUT; VON BEHR TROUT (Salmo fario).

The brown trout is widely distributed in continental Europe and the British Isles, inhabiting lakes as well as streams, but it is the "brook trout" of the continental European countries. Under favorable conditions it is known to grow to over 20 pounds, but as a true brook trout it seldom registers over 1 pound in weight.

The brown trout thrives in clear, cold, rapid streams and at the mouth of streams tributary to lakes, having much the same habits as our eastern brook trout. It is by some regarded highly as a game fish, taking either bait or artificial fly. The best fly fishing is usually toward night. As a game and food fish it is in its prime from May to September. Its flesh is very agreeable in flavor. Spawning begins in October.

The brown trout has a rather extensive distribution in the park, although only a single plant of 9,300 fish was made in Nez Perce Creek in 1890. The fish now inhabits the Madison, Gibbon, and Firehole Rivers. In the last named it is found from its junction with the Gibbon to Keppler Cascades and is particularly numerous in Nez Perce Creek, Little Firehole River below Mystic Falls, and Iron Creek. In the main streams fish have been taken weighing up to 8 pounds. In the park, as elsewhere, the brown trout has the reputation of being antagonistic to other trouts and of increasing in size and abundance at the expense of the others.

Mary Trowbridge Townsend, in her interesting article on trout fishing in the park (l. c.), mentioned a brown trout from the Firehole River:

A good 4-pounder, and unusual marking, large yellow spots encircled by black, with great brilliancy of iridescent color. * * * I took afterwards several of the same variety, known in the park as the Von Behr trout, and which I have since found to be the same Salmo fario, the veritable trout of Izaak Walton.

FIG. 6.—European brown trout; Von Behr trout.

7. LAKE TROUT; MACKINAW TROUT (Cristivomer namaycush).

The lake trout, otherwise known as laker, lunge, togue, Mackinaw trout, etc., is of wide northern distribution. In British America it ranges from the Atlantic to the Pacific coasts and northward to the Arctic Ocean. In the United States it is found in many of the larger and deeper lakes in New England and New York, in the Great Lakes Basin, and in a few localities in the Western States, as Montana and Idaho. It occurs also in Alaska. It has also been spread by fish-cultural operations into waters where it did not previously exist.

The lake trout owes its presence in the park to two plants of 30,000 and 12,000 fingerlings in Shoshone Lake and Lewis Lake, respectively, in 1890. The fish is now common in those waters, especially around the shores, and was formerly taken in large quantities to supply the park hotels. It is found also in the "canal" connecting the two large lakes. In some waters it attains a very large size. Examples weighing over 100 pounds have been reported from the Great Lakes, and in former years the average weight of the fish in the commercial fisheries of those waters was stated at 20 to 30 pounds. At this time, however, 10 to 15 pounds can be considered large.

Park Ranger Dewing reports that in 1915 he saw a lake trout that weighed 32 pounds caught in Shoshone Lake by a soldier. Mounted specimens of two large lake trout from Shoshone Lake are in the lobby at Old Faithful Inn. One taken July 13, 1912, by Pete Bergendorf, hotel fisherman, weighed 12 pounds, the other, 39 inches long, weighed 21 pounds. In the summer of 1911 Howard Eaton with a party fished in Lewis Lake and in one day caught 200 pounds of lake trout. The largest fish was 39-1/2 inches long and weighed 20 pounds; another was 34 inches long.

According to A. H. Dinsmore, as early as 1901 the lake trout had spread from Lewis Lake and become abundant in Lewis River below the upper falls. The fish has been reported also below Idaho Falls and has passed up through the tributary comnig from Jenny Lake, in which water it occurs in numbers about equal to the native trout, and specimens are recorded from the Buffalo Fork of the Snake River.

The large size of the lake trout affords its chief attraction as a game fish, for it is not ordinarily a very active fighter, although a powerful antagonist. It is usually caught by deep trolling, but is sometimes found at the surface and is occasionally taken on an artificial fly. The fish may be caught by trolling or casting with artificial or natural baits.

Opinions differ regarding its table qualities, and, as with most fishes, much depends upon how it is prepared and cooked. It is a very oily fish and often has an unpleasant, strong, oily flavor. This may be obviated, however, by removing the skin before the fish is cooked. The best method of cooking it is by boiling, serving with mayonnaise dressing or egg sauce.

Mr. Clark (l. c.) wrote in 1908 that the lake trout were plentiful in Shoshone Lake and Lewis Lake and River, and that they could be caught in the canal between Shoshone and Lewis Lakes as fast as one could throw in a trolling spoon, and he remarked that they were large and fat. On August 6, 1919, Mr. Dinsmore caught a 4-pound fish on a feathered spinner, in the canal off Point of Rocks.

FIG. 7—Lake trout; Mackinaw trout.

8. EASTERN BROOK TROUT; SPECKLED TROUT (Salvelinus fontinalis).

The natural western limit of this brook trout in the United States is northeastern Minnesota. It inhabits lakes as well as streams and varies in size according to locality. It does not flourish in water temperature over 68° F., and about 50° F. is preferable. The largest trout of this species authentically recorded weighed somewhat over 12-1/2 pounds. In some lakes trout of 5 or 6 pounds are not uncommon, but such large fish are seldom found in streams unless the streams are tributary to fairly large lakes. In streams of moderate size trout of 1 or 2 pounds' weight are to be considered large, and in most brooks a trout of one-half or three-fourths pound is an exception, at least in recent years. Its spawning season is in fall.

Plants of eastern brook trout have been made by the Bureau of Fisheries in various park waters, and the fish is now abundant and widely distributed. It is known to occur in Gardiner River and its tributaries with their branches, particularly those of the west side: Glen, Fawn, Panther, Indian, Willow, Winter, Straight, and Obsidian Creeks; Swan, Grizzly, and Beaver Lakes; Gibbon and Madison Rivers; Solfatara Creek; Virginia Meadows; Firehole River, above Kepler Cascades, where, according to the 1897 report of the superintendent of the park, this trout was very abunant and between its junction with the Gibbon and the lower falls; Upper Little Firehole; Upper Nez Perce Creek, but, according to Park Ranger Dewing, not in lower Nez Perce. According to Mr. Dinsmore it is found in Juniper Creek, a tributary of the Upper Nez Perce, and it occurs in Lone Star Creek and Spring Creek. Tower and Carnelian Creeks above the falls contain it, according to Mr. Dinsmore. It is abundant in Shoshone Creek, and according to the park superintendent's 1897 report that creek was alive with brook trout up to 1-1/2 pounds in weight. Small fish are found in lower De Lacy Creek.

The brook trout is one of the most noted and esteemed of American game fishes, but there must be something besides activity that makes it such a general favorite, as in that respect it is surpassed by several others. One appealing attribute is its beauty of coloration, and another its delicacy of flavor, which is hardly surpassed by any other fish.

The brook trout may be taken by almost any method known to anglers. In open streams fly fishing is the method par excellence. In streams where overgrowth prevents fly casting, angleworms, grasshoppers, or almost any bait will be taken when the trout is feeding. Everything will be disregarded when it is not feeding. The best flies to use any body of water must be learned by experience, but the brown hackle is seldom a failure anywhere. Professor, queen of the water, Montreal, coachman, and many others are usually quite successful. Gauze-winged flies will sometimes succeed when others fail. The best time to fish for this trout is in the morning and early evening. It lurks in eddies and pools and at the foot of rapids or under overhanging banks, old stumps, or rocks.

FIG. 8.—Eastern brook trout; speckled trout.

9. YELLOW PERCH (Perca flavescens).

The yellow perch has a wide eastern distribution. It is common in the Great Lakes and the tributaries of the upper Mississippi River and in coastwise streams and lakes from Nova Scotia to North Carolina.

In 1919 this fish was found by the senior author to abound in Goose and Feather Lakes in the park. Its presence there is apparently traceable to an unofficial, unauthorized plant made many years ago by a Montana citizen, who is said to have obtained a consignment of yellow perch from the State of Washington, into which State the species had been introduced some years before.

In the park lakes the yellow perch attains a length of a foot and is most readily caught by the use of small spinners cast from shore and rapidly drawn in. Only a few of the park authorities have been aware of the occurrence of this fish in local waters. It can not be regarded as a desirable addition to the fish life of the park, and its spread to other waters than those now inhabited should be prevented. It is not usually reputed to be a game fish, and its voracious habits make it a menace to young trout. When fresh from cold water, it is one of the best of pan fishes, being firm-meated and of delicious flavor.

FIG. 9.—Yellow perch.

10. BLOB (Cottus punctulatus).

This little sculpin belongs in the Missouri Basin and abounds in some of the waters of the park. It has been reported to swarm in the grassy-bottom portions of the Madison and Gibbon Rivers and in Canyon Creek and to be numerous in the Gibbon above the falls. It is known also from the Firehole below the falls. The presence of this fish in the Gibbon River above the falls is a freak in distribution that has not been explained. The blob is probably justly accused of being destructive to the eggs of other fishes and appears to be of little use, unless possibly as bait for large trout. It can be taken with a small baited hook. It attains a length of 5 inches.

FIG. 10.—Blob.

11. LONGNOSE SUCKER (Catostomus catostomus).

This species is of wide natural distribution in northern waters, its geographical range being from the Pacific to the Atlantic coasts and into the Arctic regions. It attains a length of 18 inches and a weight of several pounds. Its spawning time is spring and early summer when the males have their anal fin profusely covered with tubercles and the side of the body with a broad red stripe more or less diffuse on the edges. It is not sought as a game fish, but sometimes takes a baited hook and fights fairly well. When taken from cool water and cooked at once it is a good-flavored pan fish, although somewhat bony. It is abundant in Yellowstone and Gardiner Rivers below the Osprey, Undine, and Rustic Falls.

FIG. 11.—Longnose sucker.

12. ROSYSIDE SUCKER (Catostomus ardens).

This sucker is abundant in the Snake River Basin above Shoshone Falls. It is reported from Heart Lake and Witch Creek and is said to ascend the latter into very warm water flowing from Heart Lake Geyser Basin. Like the longnose sucker, it spawns in spring or early summer. It will also take a baited hook and is edible but not as palatable as the other sucker. In Heart Lake and Witch Creek the alimentary tract of this sucker is infested by parasitic worms, which, although offensive to the eye, do not render the fish harmful as food. Affected fish, however, are likely to be lean and unpalatable.

FIG. 12—Rosyside sucker.

13. CHUB (Leuciscus lineatus).

This chub, known in the books as Utah Lake chub, is one of the most widely distributed of the genus and abounds in the Snake River Basin above Shoshone Falls; also in Yellowstone Lake and other places in the park. Chubs from cool water are not to be despised in game and food qualities. The species reaches a length of 12 or 15 inches or more and is said to be destructive to the eggs and young of trout. No worms have been found in its alimentary canal. It spawns in spring and early summer.

Dr. Jordan says: "Chubs ascend Witch Creek until they reach water fairly to be called hot, and the sucker is not far behind," enduring a temperature of 88° F.

FIG. 13.—Chub.

14. SILVERSIDE MINNOW (Leuciscus hydrophlox).

This little fish is too small to be of much use for other than food or bait for trout, attaining a length of only 3 to 5 inches. It occurs in some of the sources of the Snake River in the park, particularly Heart Lake and Witch Creek. It spawns in spring.

FIG. 14.—Silverside minnow.

15. LONGNOSE DACE (Rhinichthys dulcis).

This little minnow, attaining a maximum length of only about 5 inches, is food for trout and useful as bait. It is found in Heart Lake and Witch Creek and also in Gardiner River below Osprey. Undine, and Rustic Falls.

FIG. 15.—Longnose dace.

16. DUSKY DACE (Agosia nubila).

The little dusky dace, seldom over 3-1/2 inches in length, is extremely abundant and widely distributed in the Columbia River Basin. In the park it has been recorded from Heart Lake and Witch Creek. It is useful as food for larger fishes and as bait for trout.

FIG. 16.—Dusky dace.