66 



THE MIGRATION AND CONSERVATION OF SALMON 



River, a large tributary of Shuswap Lake, 

 were liberated from rearing ponds at Taft 

 into Eagle River. In 1933, 15 fisb appeared 

 at tbe counting fence of which two were 

 marked individuals. The experiment in the 

 reestablishment of sockeye salmon runs to 

 this river by transplantation has thus met 

 with little success. 



Experiments in Marking Young 



Marking young salmon has been tried as 

 a means of securing evidence of the return 

 to spawning areas ; both fry and fingerlings 

 have been used. One of the first experiments 

 of this kind was that of Chamberlain (1907) . 

 He mentions briefly some earlier experiments 

 and describes his own in August 1903, when 

 1,600 sockeye fry reared at the Fortmann 

 Hatchery from 1,902 eggs were marked by 

 excising both ventrals. They were released 

 in the Naha River just above the hatchery. 

 In 1906 between 50 and 100 adult sockeyes 

 with ventral fins missing were reported by 

 the hatchery superintendent at Yes Lake, 

 which is miles away across the Behm Canal. 

 Only two such fish were obtained at the 

 Fortmann Hatchery in 1906 and seven more 

 were taken there in 1907. "This result is 

 a direct refutation of the homing theory" 

 writes Chamberlain (p. 78). He outlined 

 some other experiments which yielded no 

 positive results. His article contains im- 

 portant data on the biology, life history and 

 differentiation of the species of Pacific sal- 

 mon. It has not received appropriate recog- 

 nition from later workers. For reasons not 

 adequately discussed this work has been set 

 aside by later writers as inconclusive. 



When I was first on the Naha River in 

 Alaska I was told of this work and attempted 

 to arouse interest in the experiments. It was 

 difficult to do so as every one was thoroughly 

 convinced that the fish would come back, so 

 that the results of the experiment were of 

 no importance. 



The method has more recently been widely 

 employed and apparently incidentally tried 

 at some places but not well followed up. I 

 have been told personally of the appearance 

 of such marked fish at points where the ob- 



servers did not succeed in tracing the fish 

 to any source where experiments in marking 

 young fish were being conducted. Reports 

 of marked fish are subject to various errors 

 and cannot be accepted without careful 

 verification; nevertheless accounts of most 

 experiments betray two defects. First, pub- 

 lic records have not been made of all such 

 experiments ; second, and more unfortunate, 

 is the fact that little effort has been made to 

 follow up and report in detail the results 

 even of the larger and more significant ex- 

 periments. Where any reports at all have 

 been published they are confined to a brief 

 statement of the number recovered. I have 

 not found records indicating the extent of 

 the area combed for returns of the experi- 

 ments. While such records would be im- 

 perfect in any event, evidence supporting 

 the home-stream theory has been more as- 

 siduously sought than any which might in- 

 dicate exceptions to it. Of course, any proof 

 of scattering would be at best difficult to 

 secure and imperfect in any case, but those 

 difficulties make the scanty records one 

 might obtain of greater value in testing the 

 theory than the evidence on the other side. 

 Extensive tests by marking young fish 

 have been made by Rich on spring salmon, 

 by Foerster on sockeye salmon and most 

 recently by Davidson (1934) and Pritchard 

 (1938) on pink salmon. The most extended 

 discussion of experiments in marking young 

 salmon is that given by Rich and Holmes 

 (1929) who reported on work done with 

 chinooks on the Columbia River between 

 1916 and 1927. They discarded reports of 

 earlier experiments made by Hubbard. 

 Chamberlain and some others as doubtful 

 cases because of imperfect methods. Of 

 more careful experiments which they made 

 the results are summarized thus : * ' Returns 

 range from one out of 50,000 liberated to 

 one out of 300 liberated ; these figures have 

 very little significance, however, because 

 they represent not the total returns but an 

 unknown and varying proportion of the 

 total." One may fairly ask whether the 

 large discrepancy is not of some significance 

 and should have been passed without further 

 analysis. One must bear in mind, to be 



