PROGEESS IN BIOLOGICAL IISTQUIRIES, 19 2 7 217 



tagged 700 red salmon taken from a trap near Broken Point. These 

 proved to be chiefly Karluk River fish, as a very large percentage of 

 the tags were recovered from the fishery at the mouth of this river 

 or from points intermediate between there and the place of tagging. 



COLUMBIA RIVER SALMON 



Observations on the returns from salmon-marking experiments 

 conducted on the Columbia River have been continued by H. B. 

 Holmes. Approximately 600 mature salmon, which had been marked 

 when they were liberated from the hatcheries as fingerlings, were 

 recovered when they returned to the Columbia River to spawn. Ap- 

 proximately 450 chinook salmon have now been recovered from a 

 marking of 100,000 fingerlings liberated at the Big White Salmon 

 River hatchery during the spring of 1923. This is the greatest num- 

 ber recovered from an experiment with chinook salmon. In experi- 

 ments with sockeye salmon, however, ten times this number of mature 

 fish were recovered, but the reason for the difference in survival in 

 the two species remains undiscovered. 



Returns from exp)eriments with sockeye salmon indicate that the 

 age at which these fish reach maturity is determined by heredity; 

 that is, fish whose parents spawned in their fourth year will mature 

 predominantly in their fourth year, whereas 5-year-old parents pro- 

 duce a predominance of fifth-year spawners. The data concerning 

 this question are as yet too meager to be considered as conclusive. 

 Additional information is to be expected from future returns from 

 experiments now in progress. 



Two new marking experiments were begun during the year. One 

 of these was designed to give further evidence of the relative in- 

 fluence of heredity and early environment upon the habits of the 

 fish. Information on this subject is of great practical importance 

 in connection with the practice of transferring eggs from one hatch- 

 ei-y to another. The information received to date would tend to dis- 

 courage this practice. For example, records obtained in the past 

 season have shown that when eggs taken on one of the lower tribu- 

 taries of the Columbia were transferred to a station in the head- 

 waters the fish that developed from them did not return to the trib- 

 utary in which the eggs were taken, and they started their migration 

 too late in the season to allow time for the long migration to the 

 headwaters. As a result, it is possible that none of these fish suc- 

 ceeded in spawning. On the other hand, salmon that are planted in 

 their native tributary almost invariably return to it to spawn. 



EMBRYOLOGY OF THE CHINOOK SALMON 



A study of the development of the chinook salmon Avas undertaken 

 during the year by Dr. G. C. Price, of Stanford University. Partic- 

 ular attention was paid to the influence of temperature on the rate 

 of development, and it has been shown that the so-called " tempera- 

 ture-imit system," which is in common use in salmon hatcheries for 

 keeping account of the development of the eggs, does not state this 

 relationsliip correctly. Instead of a simple, direct relationship be- 

 tween temperature and the rate of development, as called for by 



