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Appendices to Thirty-sixth Annual Report 



of salmon captured and canned are ostensibly provided against, by the 

 establishment of many and large hatcheries, and if the commercial fishing 

 becomes more intense, the simple remedy is to increase the hatcheries at 

 State expense. Incidentally, it is somewhat significant that at the present 

 time the salmon fishery authorities in that region are becoming somewhat 

 alarmed by the decline, although the hatcheries seem to have increased in 

 number. When, however, we are faced by a condition such as that of the 

 Forth, where the evil at the root of the salmon decline is pollution of a 

 gross kind, hatching, whether natural or artificial, is no remedy. The 

 pollutions of the tideway have to be gone through by the young fish on 

 their first descent to the sea, as by the adult fish on their return. Special 

 attention has recently been given to this subject in view, largely, of the 

 possibilities of food production. In my opinion, it has always been very 

 difficult to establish a clear case in favour of artificial hatching, because it 

 is very difficult to obtain definite and convincing proof that hatching 

 operations can be carried on with the certain hope of success. I do not 

 for a moment say that artificial hatching cannot be shown to have 

 succeeded, but it has always appeared to me that the conditions under 

 which success can be secured are somewhat uncertain. 



One may state without contradiction, I fancy, that the hatching of 

 purely fresh water fish> including trout, is a very different thing from the 

 hatching of a migratory fish like the salmon. This is because the time 

 of the first migration to the sea appears to be the time of greatest danger 

 to the salmon, and to be the period in the fish's life when most loss occurs. 

 Salmon eggs are buried in the gravel of the river bed during the time of 

 incubation, and in this way are protected from their numerous enemies. 

 I do not say that the protection is absolute, but it appears to me that if 

 the protection were not good, either we should have had no great stock of 

 salmon in the past, or, in order that a natural and inevitable loss should 

 be overcome, the salmon naturally, like a herring (also in view of past 

 abundance) would have laid a much greater number of eggs. The actual 

 hatching, whether of salmon or of trout eggs, is a comparatively simple 

 business, and in hatcheries a high percentage of healthy alevins is common. 



We don't know very much about the percentage attained by Nature's 

 method, but I notice that those who advocate artificial hatching usually 

 take it for granted that the protection of a hatchery gives a far better result 

 in this respect than Nature's method can possibly do. I have always been 

 sceptical of this opinion. It is certainly the case that in streams where a 

 bed of rock is covered by only a shallow amount of gravel, the floods which 

 rise with great rapidity and to a great height under modern conditions of 

 land drainage, are likely to carry away the gravel with its contained eggs. 

 It may be granted also that fishes and birds prey upon any eggs they can 

 find, and feed freely upon fry, parr, and smolts. This happens also in the 

 sea, and happens apparently in much greater degree. Still the resuscita- 

 tion of a trout stream or lake, other things being equal, is admittedly an 

 easier matter than the resuscitation of a salmon river. When smolts go to 

 the sea, they pass completely beyond the control of those who have hatched 

 and tended them. They have learned something of enemies on their way 

 to the sea, but they now fall into the midst of a host of new enemies. The 

 pike and the cormorant may have dashed at them in the river, but on 

 entering the sea, a shoal of coal fish may be in wait for them. To run the 

 gauntlet of these is indeed difficult, and we know of cases where for many 

 days, during the smolt descent, shoals of coal fishes have devoured smolts 

 steadily. I have known of 16 parr in one cormorant fishing in a river, but 

 that is of no moment compared to 5 or 6 smolts in each of a shoal of coal 

 fish day after day. The run of smolts is inevitably cut down to a very 



