278 REPORT OP COMMISSIONER OF FISH AND FISHERIES. 



waters. The testimony secured on this subject did, however, empha- 

 size the fact that the mortality after spawning is very great, and is 

 shared by all the species of Oncorhynchus. The waters about and 

 directly below the numerous spawning-grounds become charged with 

 great numbers of dead salmon, whose decaying bodies fill the air with 

 the odors of putrefaction, but, while the stench becomes almost unbear- 

 able, no widespread pollution of the Fraser or Skagit rivers seems to 

 result from this cause. Detailed observations to determine the pro- 

 portion of deaths are wholly lacking. Those who have observed the 

 conditions are not in accord in their deductions, thougb all agree in 

 placing the death rate very high, especially as regards the humpback, 

 dog, and silver salmon, as well as the sockeye. Some feel confident 

 that of these species none survive, while others are equally certain that 

 only a part meet death. 



The only serious attempt at a solution of thi;s problem in British 

 Columbia was made by the late Thomas Mowat, whose experiments, 

 however, were cut short by his unfortunately early death. The most 

 complete account of his observations and deductions that we have seen 

 are contained in an unpublished letter written in 1890, from which the 

 following is an extract : 



I have much pleasure in informing you that I have proof without doubt that the 

 Oncorhynchus or Pacific salmon do in many cases return to fresh water annually 

 for the purpose of reproducing their species, I have proof of this in the case of the 

 quinnat (0. tschawytscha) and sockeye (O. nerka), and I am confident from observa- 

 tions I have made that the coho (0. kisutch) do return in larger numbers than those 

 first mentioned. 



During the seasons of 1884, 1885, and 1886, I made use of a leather or harness- 

 maker's punch to mark the quinnat salmon after they had been partially stripped of 

 their eggs and were obliged to be returned to the pens. The marking was done by 

 punching one or more holes through the adipose dorsal fin, then passing a piece of 

 colored cotton cloth or twine through the hole, so as to distinguish them from the 

 fish that had not been handled. Sometimes we cut a portion or the whole of this 

 fin off, and those fish were returned to the water after we had finished stripping 

 them. Two successive years later a few of the fish so marked passed through our 

 hands and were recognized, and I learned that some had been taken by the netters. 

 It must be understood that the strings were not left on the fish. The fin was found 

 to be withered somewhat, with the hole partially grown up. Since the season of 

 1887 we have been operating on the sockeye, and, as I have already described, some 

 of these were marked in a similar way, but owing to having so many in the pens we 

 had to keep different marks on them, so that the tails of some were bent or doubled 

 up, a piece being taken out. Two of the fish marked in this manner were taken by 

 netters this season and sent to me. 



My contention has always been that at least four species of our salmon return to 

 the rivers to reproduce. The fourth, including those alluded to, is the steelhead, of 

 which none die except by accident. My opinion is that 75 per cent of the quinnat 

 salmon survive that ascend from 75 to 100 miles inland; those that ascend from 100 

 to 1,000 miles, or reach the summit of the Rocky Mountains, are reduced from 

 various causes down to from 5 to 25 per cent. The percentage of the sockeye that sur- 

 vive are slightly under the quinnat, while those of the cohoes are over, as they do 

 not ascend so far inland and have a better chance of returning. The qualla and 

 humpbacks die in larger numbers, as they are more pugnacious, spawn in shallow 

 water, and are more liable to disease. I quite agree with yon as to the views 



