626 REPORT OF COMMISSIONER OF FISH AND FISHERIES. [2] 



quantity of it will gather between the small stones on the bottom, and 

 will thus expose to the danger of destruction those eggs which have 

 remained in the spawning places. Unfortunately, however, large masses 

 of eggs, probably by far the larger portion, do not remain in the spawn- 

 ing places, but are carried away by the current and only find a resting- 

 place farther down the river, where the current is not so strong and 

 where there are frequently such large piles of sawdust that the eggs are 

 completely buried in them and are of course destroyed. This is all the 

 more injurious to the eggs, as, owing to climatic reasons, the increase 

 of the salmon is principally dependent on those eggs which are carried 

 away from the spawning places and which settle down in the calm and 

 deep portions of the river. The eggs which remain in the spawning 

 places are, in our climate, frequently entirely destroyed by influences 

 which are beyond human control. 



It is well known that the quantity of water in our rivers is greatly 

 diminished during winter, so that all the water contained in the river 

 finds sufficient room in a narrow channel, whilst the greater portion of 

 the river bed lies dry. As the salmon spawn in shallow waters, the 

 greater portion of those eggs which are not carried away by the current 

 into deep water will remain on the dry land for a longer or shorter period, 

 exposed to the destructive influence of frost and ice, and will thus inev- 

 itably be destroyed. Those eggs which have escaped this danger are 

 threatened by another and not less serious one, namely, the floating ice, 

 which often scrapes the bottom, especially in shallow places, so violently 

 as to change the bed of the river and carry away immense pieces of rock. 

 It may well be imagined what destruction is thereby caused to the eggs 

 lying in such places, and also to the newly-hatched fish. 



In comparison with the impurities brought to the river-bottoms by 

 the sawdust, and the consequent destruction of the fish eggs, its other 

 injurious influences on the fisheries are hardly to be taken into account, 

 although in themselves they are by no means inconsiderable. Thus 

 there can be hardly a doubt, that when the water rises and causes the 

 masses of sawdust which have gathered in the river to move, a large 

 number of young fish are carried away with it and are gradually buried 

 in the newly -formed piles of sawdust. This is particularly the case 

 during spring, when the young fish are as yet very weak and cannot 

 swim far. It is also highly probable that the sawdust floating about 

 in the water kills a large number of young fish in the act of breathing, 

 because they can hardly avoid swallowing particles of it which stick fast in 

 the gills and thus eventually cause their death.* I must finally also men- 



*It is a very general opinion that this also applies to the grown salmon, as in those 

 riveis which are lull of sawdust dead salmon have often been found whose mouths 

 and gills were, completely tilled with sawdust. I am not prepared to say whether this 

 opinion is correct. Such cases as the one just mentioned are at any rate not so com- 

 mon as to deserve special attention. It has also beeu said that sawdust will drive 

 the salmon entirely away from a river, but I thiuk that this is very improbable, and 

 could only bo possible in cases where a river has beeu completely tilled with it. 



