FISHERY BULLETIN: VOL, 71, NO. 2 



3.1 to 4.2 mm for mountain whitefish. Booke 

 (1970) postulated that the large-egg coregonine 

 species gave rise to small-egg types. He admitted 

 that the small-egg size of the pygmy whitefish 

 does not fit his hypothesis because the species 

 is considered to be the most primitive of the 

 subfamily Coregoninae but that this may be a 

 specialized character; and if the pygmy white- 

 fish had the growth potential of the other 

 species in the genus, it would probably have a 

 larger egg. Also compensating for the low egg 

 number per female, the pygmy whitefish spawns 

 at an earlier age. Most mountain whitefish do 

 not mature until their third or fourth year 

 (Sigler, 1951; Brown, 1952), 1 to 2 years 

 later than female pygmy whitefish and 2 years 

 later than male pygmy whitefish. The early 

 maturation and shorter life span of the male 

 pygmy whitefish ensures greater fecundity and 

 abundance of the species at lower consumption 

 of food. 



Evidence suggests strongly that direct com- 

 petition between the two whitefish species on 

 the spawning grounds is avoided by a dif- 

 ference in spawning time. Booke (1970) noted 

 that large-egg coregonines spawn earlier than 

 those with small eggs. From the information 

 available, it appears that in Montana the large- 

 egg mountain whitefish spawns about a month 

 earlier than the small-egg pygmy whitefish. 



The small size and consequential small egg 

 diameter of the pygmy whitefish may be ex- 

 plained by the rigors of the glacial period. 

 The known range of the species is restricted 

 to recently glaciated areas. During the glacial 

 period it probably retreated less than other 

 coregonines from the glacial margins. The 

 small size and early spawning age were very 

 possibly adaptations for survival in cold and 

 nutrient-poor waters. 



LITERATURE CITED 



Booke, H. E. 



1970. Speciation parameters in coregonine fishes: 

 I. Egg-size IL Karyotype. In C. C. Lindsey and 



C. S. Woods (editors). Biology of corgonid fishes, 



p. 61-66. Univ. Manit. Press, Winnipeg. 

 Brown, C. J. D. 



1952. Spawning habits and early development of 



the mountain whitefish, Prosopiitm williainsoni, in 



Montana. Copeia 1952: 109-1 13. 

 1971. Fishes of Montana. Big Sky Books, Mont. 



State Univ., Bozeman, 207 p. 

 Brunson, R. B., and H. W. Newman. 



1951. The summer food of Coregomis clupeaformis 



from Yellow Bay, Flathead Lake, Montana. Proc. 



Mont. Acad. Sci. 10:5-7. 



ESCHMEYER, P. H., AND R. M. BaILEY. 



1955. The pygmy whitefish, Coregonus coiilteri, 

 in Lake Superior. Trans. Am. Fish. Soc. 84:161- 

 199. 

 Evans, H. E. 



1948. Clearing and staining small vertebrates in 

 toto, for demonstrating ossification. Turtox News 

 26:42-47. 

 Heard, W. R., and W. L. Hartman. 



1966. Pygmy whitefish Prosopiuni coulteri in the 

 Naknek River system of southwest Alaska. U.S. 

 Fish and Wildl. Serv., Fish. Bull. 65:555-579. 

 Holt, R. D. 



1960. Comparative morphometry of the mountain 

 whitefish (Prosopiitm williainsoni). Copeia 1960: 

 192-200. 

 HuBBS, C. L., and K. F. Lagler. 



1964. Fishes of the Great Lakes Region. Univ. 

 Mich. Press, Ann Arbor, 213 p. 

 McCart, p. J. 



1963. Growth and morphometry of the pygmy 

 whitefish (Prosopiitm coulteri) in British Columbia. 

 M.S. Thesis, Univ. British Columbia, Vancouver, 

 97 p. 



1970. Evidence for the existence of sibling species 

 of pygmy whitefish (Prosopiitm coulteri) in three 

 Alaskan Lakes. In C. C. Lindsey and C. S. Woods 

 (editors). Biology of coregonid fishes, p. 81-98. 

 Univ. Manit. Press, Winnipeg. 

 Rogers, D. E. 



1964. Some morphological and life history data on 

 pygmy whitefish from Wood River. In Research 

 in fisheries . . . 1963, p. 24-25. Coll. Fish., Fish. 

 Res. Inst., Univ. Wash., Contrib. 166. 



SCHULTZ, L. P. 



1941. Fishes of Glacier National Park, Montana. 

 U.S. Fish Wildl. Serv., Cons. Bull. 22, 42 p. 

 Sigler, W. F. 



1951. The life history and management of the 

 mountain whitefish Prosopiitm williamsoni (Girard) 

 in Logan River, Utah. Utah State Agric. Coll., 

 Bull. 347:1-21. 

 Weisel, G. F., and J. B. Dillon. 



1954. Observations on the pygmy whitefish, Proso- 

 piuin coulteri, from Bull Lake, Montana. Copeia 

 1954:124-127. 



596 



