350 



FISHERY BULLETIN OF THE FISH AND WILDLIFE SERVlv. 



lengths in inches at various annuli for the hybrid 

 trout in 1953 and 1954 combined were: 1, 3.7; II, 

 7.2; III, 10.5; IV, 12.8; V, 14.9; VI. 17.3; VII, 

 17.5. 



The length-weight relation for the grayling was 

 determined to be log weight = 2.7682 log length 

 — 1.2925, and for the hybrid trout log weight = 

 2.5420 log length — 0.9674, where weights are in 

 hundredths of a pound and lengths are in tenths 

 of an inch. 



The food of the grayling during its first summer 

 of life consisted of small nymphs of aquatic insects, 

 amphipods, and Daphnia. By the middle of their 

 second summer, young of the grayling were feeding 

 on the same organisms as the adults except for 

 some of the large Odonata of a size too great to be 

 ingested. Diptera larvae and pupae were the 

 major food items found in 40 of the grayling and 

 10 of the trout from Grebe Lake during the 1952 

 to 1954 seasons. 



From a voluntary creel census on Grebe Lake 

 the following estimations of fishing pressure were 

 made. In 1953, 780 fishermen removed 2,148 fish. 

 During 1954, 818 anglers caught 2,863 fish. The 

 catch the first year was 3.1 fish per fisherman, the 

 second, 3.5. Fishing pressure on Grebe Lake was 

 light during the two seasons with a harvest of 7.1 

 percent of the estimated population or about 6 

 pounds per acre in 1953, and 9.9 percent or 

 approximately 8 pounds per acre in 1954. 



LITERATURE CITED 



Alvord, W. 



1954. Validity of age determinations from scales of 



brown trout, rainbow trout, and brook trout. 



Trans. Amer. Fish. Soc, Vol. 83 (1953), 



pp. 91-103. 

 Brasch, J. 



1949. Notes on natural reproduction of the eastern 



brook trout (<S. fontinalis) with a preliminary 



report of several experiments on the subject. 



Wisconsin Cons. Dept., Madison, Sect, of 



Fish. Biol., Invest. Rept. No. 653. Mimeo. 



9 pp. 

 Brown, C. J. D. 



1938a. The feeding habits of the Montana grayling 



(Thymallus montanus). Jour. Wildlife Mgt., 



Vol. 2, No. 3, pp. 135-145. 

 1938b. Observations on the life-history and breeding 



habits of the Montana grayling. Copeia, 



1938, No. 3, pp. 132-136. 

 1943. Age and growth of Montana grayling. Jour. 



Wildlife Mgt., Vol. 7, No. 4, pp. 353-364. 



Brown, C. J. D., and C. Buck, Jr. 



1939. When do trout and grayling fry begin to take 



food? Jour. Wildlife Mgt., Vol. 3, No. 2, 



pp. 134-140. 

 Chapman, D. G. 



1948. A mathematical study of confidence limits oi 



salmon populations calculated from sample 

 tag ratios. Internat. Pac. Salmon Fish. 

 Comm, Bull. 2, pp. 67-85. 



Chapman, D. G. 



1952. Inverse, multiple and sequential sample cen- 

 suses. Biometrics, Vol. 8, No. 4, pp. 286- 

 306. 



Cooper, G. P., and K. F. Lagler. 



1956. Appraisal of methods of fish population study. 

 Part III. The measurement of fish popu- 

 lation size. Trans. Twenty-first N. Amer. 

 Wildlife Conf., pp. 281-297. 



Creaser, C. W., and E. P. Creaser. 



1935. The greyling in Michigan. Pap. Mich. Acad. 



Sci., Arts and Lett., Vol. 20, pp. 599-608. 

 Crowe, W. R. 



1950. Construction and use of small trap nets. 



Prog. Fish-Cult., Vol. 12, No. 4, pp. 185-192. 

 De Lury, D. B. 



1951. On the planning of experiments for the esti- 



mation of fish populations. Jour. Fish. Res. 

 Bd. Canada, Vol. 8, No. 4, pp. 281-307. 

 Fabricius, E., and Karl-Jacob Gustafson. 



1955. Observations on the spawning behaviour of the 

 grayling, Thymallus thymallus (L.). Inst. 

 Freshwater Res., Drottningholm, Rept. No. 

 36, 103 pp. 



FoERSTER, R. E. 



1938. An investigation of the relative efficiencies of 

 natural and artificial propagation ot sockeye 

 salmon (Oncorhynchus nerka) at Cultus Lake. 

 British Columbia. Jour. Fish. Res. Bd. 

 Canada, Vol. 4, No. 3, pp. 151-161. 

 Forbes, S. A. 



1893. Aquatic invertebrate fauna of Yellowstone 

 National Park, Wyoming. Bull. U. S. Fish 

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 Franklin, Sir J. 



1823. Narrative of a journey to the shores of the 

 Polar Sea in the years 1819, '20, '21, '22. 

 London, J. Murray, 768 pp. 

 Gustafson, Karl-Jacob. 



1949. Movements and growth of grayling. Inst. 



Fresh water Res., Drottningholm, Rept. No. 



29, 44 pp. 

 Henshall, J. A. 



1902. Food and game fishes of the Rocky Mountain 



Region. Trans. Amer. Fish. Soc, Vol. 31 



(1902), pp. 74-88. 

 Hile, R. 



1936. Age and growth of the Cisco, Leucichlhys artedi 



(Le Sueur), in the lakes of the northeastern 

 highlands, Wisconsin. Bull. U. S. Bur. Fish., 

 Vol. 48 (1935), pp. 211-317. 



