294 SALMON OF THE KARLUK RIVER, ALASKA 



22. Removal of the adipose and right, left, or both ventral fins is considered 

 preferable in marking fish rather than the removal of adipose and dorsal, or adipose 

 and one pectoral fin. 



23. The adipose and dorsal mark compared equally well with the adipose and 

 right ventral mark in the returns. However, the removal of the dorsal fin left a 

 large wound on the back of the young fish which may cause a high rate of mortality. 



24. The right and left pectoral marks are definitely inferior to the others, due 

 probably to the need of these fins by the fish for maintaining their equilibrium when 

 eluding their enemies. 



25. The total calculated returns from those experiments wherein either the 

 adipose and left ventral, adipose and right ventral, or adipose and both ventral fins 

 were amputated were 20.8 (incomplete), 22.3, 21.0, 23.6, 20.5, and 20.5 percent for 

 the experiments of 1926, 1929, 1930, 1931, 1932, and 1933, respectively. 



26. The average return from the marking of 3-year seaward migrants was 17.4 

 percent and for the 4-year seaward migrants 25.7 percent. 



27. While a slight differential mortality probably exists between the marked 

 and the unmarked fish, it is not considered to be great in the case of the fish marked 

 by the amputation of either the left, right, or both ventral fins, as the survival of 

 the marked fish during their stay in the ocean is relatively high, averaging 21.45 

 percent. 



28. The mortality of Karluk River red salmon during the fresh-water stage of 

 their life history is usually over 99 percent. 



LITERATURE CITED 



Association of Official Agricultural Chemists. 



1930. Nitrogen in the form of nitrite — official, p. 405. Official and Tentative Methods of 

 Analysis. Assoc. Official Agr. Chem. third edition, 593 pp. Wash. 

 Davidson, Frederick A. 



1934. The homing instinct and age at maturity of pink salmon (Oncorhynchus gorbuscha). 

 Bull. U. S. Bureau of Fisheries, vol. XLVIII, 1933 (1934) pp. 27-39, Wash. 

 Dienert, M. M., and F. Wandenbulcke. 



1923. On the determination of silica in water. Compt. rend. soc. biol. Paris 176: 1478-1480. 

 Fisher, R. A. 



1930. Statistical methods for research workers. 283 pp. Oliver and Boyd, London. 

 Foerster, R. E. 



1934. An investigation of the life history and propagation of the sockeye salmon (Oncorhyn- 

 chus nerka) at Cultus Lake, British Columbia. No. 4. The life history cycle of the 

 1925 year class with natural propagation. Contributions to Canadian Biology and 

 Fisheries, vol. VIII, No. 27 (Series A, General, No. 42). Toronto. 



1936a. An investigation of the life history and propagation of the sockeye salmon {Oncorhyn- 

 chus nerka) at Cultus Lake, British Columbia. No. 5. The life history cycle of the 

 1926 year class with artificial propagation involving the liberation of free-swimming 

 fry. Jour. Biol. Bd. Can. vol. 2, No. 3, pp. 311-333. Toronto. 



1936b. The return from the sea of sockeye salmon {Oncorhynchus nerka) with special reference 

 to percentage survival, sex proportions, and progress of migration. Jour. Biol. Bd. 

 Can. vol. 3, No. 1, pp. 26-42. Toronto. 



