SH 167 .G8 H5 Copy 1 f DEPARTMENT OF COMMERCE AND LABOR BUREAU OF nSHERIES GEORGE M. BOWERS, Commisaionet CULTURE OF THE MONTANA GRAYLING Bureau of Fisheries Document No. 628 WASHINGTON GOVERNMENT PRINTING OFFICE 1907 DEPARTMENT OF COMMERCE AND LABOR BUREAU OF FISHERIES GEORGE M. BOWERS. Commissioner CULTURE OF THE MONTANA GRAYLING Bureau of Fisheries Document No. 628 V\^>r.^... WASHINGTON GOVERNMENT PRINTING OFFICE 1907 'W^ Q.^ .\^^ Da of D* K-/ to (Li CULTURI OF THE MONTANA GRAYLING By James A. Henshall Superintendent U. S. Fisheries Station at Bozenian, Montana Bureau of Fisheries Document No. 628 CULTURE OF THE MONTANA GRAYLING. By James Alexander Henshall, Superintendent U. S. Fisheries Station at Brjzeman, Mont. CHARACTERIZATION OF THE SPECIES. The Montana grayling originalh^ existed only in the tributaries of the Missouri River above Great Falls, and was first noticed by Lewis and Clark, during their remarkable journey to the Pacific coast. They described it from fish taken near the headwaters of the Jeffer- son River, but did not name it, alluding to it as a new kind of white or silvery trout. It was rediscovered by James W. Milner, of the U. S. Fish Commission, in 1872, in a tributary of the Missouri near Camp Baker, Montana. He described it, and named it Thymallus rnon- tanus. At iii'st it was said to be a variety of the Michigan grayling, but it is now given specific rank. In its afhnities it is really more nearly related to the Arctic grayling (T. signifer), as may be seen from the following characterizations: Specific Characters of the Graylings. .c ^ c U,S3 >> Species. c a 6jO C c3 r3 M) o c o ■^ n ~.q y s 03 ■^ C m M n o o Q bJJta O T. signifer 5h 41 3 2A S-SS to 90-1 1 12 below angle 20-24 3i Anterior. T. tricolor oh 4 21 93-98 7+12 21-22 5i Posterior. T. montanus 5 4i 3.V 3 S-82 to 8^10 5+12 18-21 4i Anterior. a To orbit. Description. — From the examination of a large series of fresh speci- mens the following detailed description of the Montana grayling may be given: Head moderate, subconic, its length contained 5 timQS- in length of body, curving regularly from snout to dorsal line, and continuous with it. Mouth moderate, oblique, terminal, the maxillary extend- ing to the anterior border of the eye, its length 3 times in head; jaws equal. Eye large, 3* in head, nearly equal to interorbital space, and longer than snout, the pupil pyriform or pear-shaped, with the apex anterior. Teeth feeble, sparse, and uniform in size; on jaws, 3 4 CULTURE OF THE MONTANA. GRAYLING. vomer, and i)alatines; none on tongue. Gill rakers 5 + 12. Scales moderate, 82 to 85 along lateral line, with 8 rows above and 10 rows below; lateral line nearly straight, curving upward slightly toward the head. Dorsal fin long and high, the height greater than depth of body; 18 to 21 rays. Caudal fin strongly forked. Coloration: Back i)luish-gray with purplish reflections; sides and gill-covers hghter, with purple and silvery reflections, beautifully iridescent; scales with a pearly luster; belly pure white; a few V-shaped black spots between the head and middle of dorsal fin, but none posteriorly; two ol)long, bluish black blotches in cleft between opercle and branchiostegals, more pronounced in the male; a line on upper border of belly fi'om ventral to pectoral fins, dark and heavy in the male, very faint in female. Dorsal fin edged with a red or rosy border; four to seven vertical rows of red or rosy roundish spots, ocellated with white between the dorsal ra^^s; dark lilotches fornung lines between the rows of red spots. Ventral fins with three rose-colored, branching stripes along the rays, darker between. Pectoral and anal fins plain, with dark border. Origin. — It is very probable that the Arctic grayling was the parent stock fi'om winch the Michigan and ]\Iontana graylings descended; and fi"om the fact that the habitats of the tlu'ee species are so widely separated, it is not unreasonable to suppose that the IMichigan and ^lontana forms were conveyed thence fi'om the Ait tic regions during the Glacial period. This theory is strengthened l)y the fact that Elk Lake, a half nule from the ]\Iontana grayling station, is abundantly inhabited by both grayling and the lake trout {Cris- tlvomer nainaycush), \yhich. latter fish is found nowhere else west of Lake Michigan. Gume and food qus the artificial fly eagerly, and if missed at the fij'st cast will rise again and again from the tlepths of the pool, whereas the trout will seldom rise the second time to the same fly without a rest. Habits. — The Montana grayling prefers swift, clear streams of pure water, with gravelly or sandy bottom. It is quite gregarious, lying in schools in tlie deeper pools, in plain sight, and not, like the trout, concealed under bushes or overhanging banks. In search of food, \\ hich consists principally of insects and their larvte, it occasionally CULTURE OF THE MONTANA GRAYLING. 5 extends its range to streams strewn with bowlders and broken rocks. The fry subsists on minute crustaceans, as Entomostraca, and for seizing the minute organisms is furnished, hke the lake wliitefish fry, w4th two sharp, retrorse teeth in the upper jaw. Unlike the Rocky Alountain trout {Salmo clarkii), but like the salmon, the grayling will go long distances, if necessary, to find suita- ble spawning grounds. The auxiliary grayling station of the Bureau of Fisheries is on Elk Creek, one of the feeders of Red Rock Lake, at the head of the Jefferson River. At the beginning of the breeding season many grayling go up the Jefferson, through Beaverhead and Red Rock rivers, to Red Rock Lake, 14 miles in length, and through the lake to the inlets at its head, iifter spawning they return through the lake to the streams below, none stopping in the lake, as it is unsuit- able, being shallow and with an alkali bottom. At spawning time Elk Creek is fairly alive with grayling on the gravelly shallows, where their large and beautifid dorsal fins are to be seen waving like so many banners, clear of the water, in the manner of shark fins on a fiood tide. In the North Fork of the Madison River, where the water is comparatively warm, coming from the Firehole River in Yellowstone Park, the grayling spawns a month earlier than in other waters of Montana. METHOD OF ARTIFICIAL PROPACJATION. Strip [y'mg and incuhation. — One fish produces from 2,000 to 4,000 eggs, which are about one-seventh of an inch in diameter, running from 750 to 850 in nimiber to a fluid ounce. The eggs in the ripe fish lie loose in the abdominal cavity, as in the trout, and the fish is quite as easily stripped — the eggs perhaps a little harder to start, but afterward flowing freely. They are fertilized by the dry proc- ess, and fully 95 per cent are fecundated. They require much more washing than trout eggs, to free them of a glutinotis substance that otherwise would cause them to bunch. , When fij"st extruded the eggs are of a rich aml^er color, owing to the presence of a large oil drop, which renders them almost semi- buoyant; but after a few days of incubation they become hyaline or glass color, and as clear as crystal. It is imperative that they be eyed in hatching jars with a good pressure of water, to obviate all danger from btmching and fungus. If the}" are placed on ordinary fiat trays, touching each other, and exposed to a lateral current of water, they adhere in bimches, fimgus appears, and much labor is entailed in picking, ending in a great loss of eggs. After the eye- spots show the eggs may be placed on the ordinary hatching tra}^, being then much hea-sder and not likely to float oft'. The embryo becomes very active before the eye-spot appears, which occurs in about a week or ten days at a temperature of 50° F. Incubation 6 CULTURE OF THE MONTANA GRAYLING. is then coiiiplete witliin two weeks. If the water is much colder the period will be several days longer. The fry is hatched with a very small yolk sac, smaller than the egg, and this sac is absorbed in a week or ten days, the fry then becoming a free swimming animal about half an inch long, quite slender and delicate, resembling somewhat the fry of whitefish or shad. Tmnsportation of eggs. — The usual method of packing and shipping salmon and trout eggs will not answer for grayling eggs. They will not bear crowding or pressure, and must be kept at a ver}^ low tem- perature. The period of incubation being so brief, there is a possibility of their hatching in transit if they are several days en route and the temperature rises al)ove 42°. This was demonstrated the first sea- son at the Bozeman station, when the eggs were shipped in ordi- nary trout-egg cases, and even with the precaution of pacldng ice with the moss about the stack of egg trays. Before the next season I devised the refrigerator case, with double wall, by means of which the temperature can be kept at 40° or l)elow for any length of time if properly re-iced, and the eggs will reach their destination in excellent condi tion . For the better aeration of the eggs was devised also a special egg tray but one-half inch in depth, with cheese-cloth bottom. No moss is placed over the eggs on the tray, for, as before stated, they will not bear any pressure, and a piece of mosquito netting is all that is required to keep them in position. A space of 2^ to 3 inches is left between the inner wall of the refrigerator case and the stack of egg trays, and this, as well as the hopper on top of the trays, should be kept constantly tilled with ice. The hopper has perpendicular sides instead of the flaring sides usual in trout-egg cases, to facilitate re-icing of the s})ace surrounding the stack of trays during transporta- tion. The frames of tlie egg trays are 1 inch wide, so that when placed in a stack they form a wall 1 inch thick to separate the eggs from the ice, and there is no possible danger of freezing the eggs; this was demonstrated by experiment. For grayling egg-case labels the precaution "Do not expose to freezing temperature" is always erased, as unnecessary, and moreover, useless when considered in connection with the notice to express messengers to re-ice en route and to keep as cold as possible. Feeding ihe fry. — If stream water containing the minute crusta- ceans that furnish suitable food for the fry, as most streams do, can be supplied to the fry in the hatchery from the first, no artificial feeding will be necessary for a month or six weeks. If, however, only spring water can be had, great care must be exercised and the ingenuity and intelligence of the fish-culturist brought into requisition to discover the best means of feeding. It was found that fresh blood supplied CULTURE OF THE MONTANA GRAYLING. 7 before the yolk sac is entirely a]:)sorbed answers a o;ood purpose. Liver emulsion rendered as fluid as possible, and then strained through ordinary muslin, will serve to tide the fry over the precarious stage until they are a month or six weeks old, when they can be fed the same as trout fry; but during the first stages they must be watched closely and fed much more frequently than trout fry. If fresh blood can be procured and stirred until it becomes a homogeneous fluid, free from clots, it can advantageously be supplied either straight or mixed with the strained liver emulsion. But, owing to the very small size of the grayling fry, artificial feeding is under all circum- stances cjuite a problem. At the Bozeman station they have been reared to maturity in the manner mentioned with a loss of from 50 to 70 per cent; and the mature iish have been, stripped and the eggs hatched and fry planted. This has been done several seasons, though only a portion of the females yielded good eggs and many males were not in good breeding condition, possibly from a lack of their natural food and from being kept in spring water. The fry should be transferred to shallow, sunny nursery ponds with a good current of stream water, of a higher temj^erature than spring water, if possible — say from 55° to 60°. They l)egin to forage for their natural food as soon as placed in the pond, and are exceedingly active and industrious. If the w^ater is found to contain an abundance of their natural food, which can be determined by examination with the microscope, they will do well. In addition, however, it is well to feed the fry at least six times a day for several weeks; otherwise they may begin to eat each other, being very cannibalistic. Owing to this tendency it is, moreover, advisable to begin with two or three times as many fry as it is desired to rear. Output of the government grayling hatchery. — The following table is a statistical resume of the results of grayling propagation by the U. S. Bureau of Fisheries in the last decade. Output op Grayling from the IT. S. Fisheries St.\tion at Bozeman. Mont., 1898-1907. Year. Eggs collected. Eggs shipped to other stations. Fry and fingerlings distributed. Adults and yearlings distrib- uted. 1898 2, .506, 200 5,735,000 3,687,000 2, 400, 000 4,46.3,000 3,045,000 3,247,800 1,010,000 1,650,000 2,370,000 115,000 380, 000 814,000 390, 000 1,4.55,000 645,000 494,000 400, 000 642,000 2.')0,000 1,. 500, 000 4,567,000 2,449,718 1,453,461 1,130,333 974,114 2,692.200 400, 000 800,000 1,376,200 1899 1900 if), 666 11 7''1 1901 1902 18,000 368 1903 1904 905 1905....: 1906 1907 Total _ 30,114,000 5,585,000 17,343,026 40, 3S4 o LIBRftRY OF CONGRESS 002 854 171 5