SAWDU8T AND FI8H LIFE 



113 



SESSIONAL PAPER No. 22a 



the water was turned into the troughs, unless the wood was very old or had long been 

 water soaked. In these cases, the fungus does not appear to so great an extent, but 

 when the lumber is new, the fungus, except in highly oxygenated waters, invariably 

 appears very soon after the water comes in contact with the green wood. 



This fungus is one of the most deadly things in the world to trout and salmon 

 eggs. It is so destructive that if a million trout eggs were put into green lumber 

 t^-oughs to hatch, they would every one of them be killed before they hatched. Not 

 one would escape. 'Domesticated Trout,' speaking of this fungus (page 126, sixth 

 edition);, says : ' Fungus is a vegetable growth of low order, which makes its appear- 

 ance almost invariably where there is water, and especially on newly cut wood, on 

 which it eventually becomes a mass of nearly colourless or milky slime. 



' This fungus, if once present in the hatching water, will certainly attach itself 

 to the eggs, and when it does, their fate is sealed, you cannot save them from its effect, 

 for it never lets go its hold. It will surely eat out the vitality of the embryo within, 

 and will either kill it entirely or will leave a puny, lifeless, transparent creature, which 

 will in all probability never live to grow up. It cannot^ therefore, be guarded against 

 with too much care.' 



In consequence of this action on the surface of lumber under water, wooden hatch- 

 ing troughs were formerly charred, and now are all covered with a coating of asphaltum, 

 on which fungus does not grow. No fishculturists of any experience would think for 

 a moment of using wood for hatching trout or salmon eggs, without first covering 

 every part of the surface with asphaltum, or something furnishing similar protection 

 against fungus. 



Now, if the exposed surface of the three planks which form the hatching trough 

 can exercise such a deadly and universal effect on the fish eggs that are in it, what a 

 vast power of injury there must be in sawdust, in which form the exposed surfaces of 

 the wood are multiplied almost indefinitely. Take an inch board a foot square and 

 •1 educe it all to sawdust, and it will give an amount of exposed surface almost in- 

 finitely greater than the board itself. Then consider what must be the effect of throw- 

 ing tons of this sawdust every year directly upon the spawning beds of the fish, and 

 where the sawdust will float down to the spawning beds below, if there should happen 

 to be any below. From the moment the sawdust falls into the water it begins to pro- 

 duce the fatal fungus, and makes it absolutely impossible for a fish egg to hatch where 

 it is, and what is more, the invisible fungus which destroys the eggs so effectually, gets 

 into the gills of the young fish that are exposed to it and kills them also ; and, besides 

 this, by one of those wonderful instincts that are implanted in the lower animals, fish 

 will avoid a stream where the conditions of spawning are unfavourable, and sooner or 

 later will abandon a stream, the spawning beds of which are covered with sawdust. 



The writer trusts that the above considerations are sufficient to show that large 

 deposits of sawdust should be looked upon with much suspicion in streams that are 

 valued on account of the fish life that is contained in them. 



SALMO. 



Of course, a fungous growth does occur upon fish eggs, but it does not necessarily 

 come from sawdust. It is simply the case of an aquatic plant starting to grow upon 

 organic matter — the eggs, or upon the bodies of the fry when these happened to re- 

 ceive injury in any way. I have seen such growths upon both eggs and fry, and that 

 too in water that never contained a particle of sawdust. Whether this fungus is the 

 same that grows upon rotting wood I cannot say, but of course every intelligent person 

 nowadays knows that the rotting of all wood and trees, and the decay, putrifaction 

 and death of animal tissues are alike preceded and caused by a fungus or bacterial 

 growth which fastens upon the animal in the one case, or plant in the other, and 

 ultimately causes the death of the individual. 



But this fungous growth is an entirely different matter from the poisonous effects 

 of sawdust. All wood cells, whether in the tea plant or pine, contain compounds that 

 have been stored in the cell. When these cell contents are liberated and dissolve in 



22a— llj 



