114 



MARINE AND FISHERIES 



6-7 EDWARD VII., A. 1907 



water we get a solutiion wbose poisonous or other effects depend entirely upon the 

 strength of the solution. 



The experiments described in my second report showed clearly that the poisonous 

 effect of sawdust w^ater varies directly within the strength of the solution. A strong 

 aqueous extract from sawdust is so poisonous as to kill in a short time nearly all forms 

 of aquatic life. A weak solution is comparatively harmless. The question then of 

 whether any particular stream is sufficiently polluted with sawdust to kill fish life is 

 simply the question of determining whether enough sawdust has been passed into the 

 stream to poison its waters. It is a question of the strength of the sawdust solution. 

 There is no mystery about the matter. Any one who can understand the making of a 

 cup of tea can understand the making of sawdust extracts. If we wish to make a 

 strong cup of tea, we use plenty of the leaves and a comparatively small volume of 

 water. If we wish to make an infusion we use a smaller quantity of the leaves and a 

 larger volume of water. It is the principle which herbalists, druggists and medicine 

 mongers have used for thousands of years. Senna tea, chamomile tea, not to speak 

 of dozens of others, are examples of infusions such as we get by immersing sawdust 

 in water. 



Keeping this principle in mind, my work during the past summer consisted largely 

 m r.scertaining the quantity of saw^dust discharged into a stream in a given time, and 

 the total volume of water passing the mill in this same time. 



The first mill visited was one located on the way to Little Harbour, a few miles 

 from ISTew Glasgow, Nova Scotia. The mill supplies lumber to the farmers in the 

 neighbourhood. The timber, chiefly second growth spruce, and a little hemlock, is 

 drawn to the mill during the winter. In the spring, when water is plentiful in the 

 brook, the logs are sawn into boards, the sawdust and smaller refuse being discharged 

 into the stream below. 



The logs are all very small, and yield only from 40 to 100 feet per log. The total 

 cut during the past few seasons averaged only 100,000 feet. 



I*revious to my visit, no rain had fallen for about six weeks, and consequently the 

 mill was not running, on account of lack of water. The only water passing the dam 

 was that from ordinary leakage. Below the mill, the brook was nearly dry. But in 

 the spring and during summers when the rainfall was normal, smelt and sea trout 

 came up to the foot of the mill dam, and were often caught with hook and line at the 

 mill end. 



The ' by-wash ' at the side of the mill, by which the surplus water escaped when 

 the mill was not running, was a very shallow flume about 14 feet wide, 80 feet long, 

 and from 6 to 9 inches deep during the spring freshets. The total fall Avas 20 feet, 

 consequently the slope down the by-wash was a very gradual one. The proprietor of 

 the mill was of opinion that sea trout were able to pass up this by-wash and did ascend 

 it every spring. At any rate, sea trout were caught every week by boys fishing in the 

 mill dam. It was a comtnon thing for boys from New Glasgow to go out to this mill 

 pond on Saturdays and take home with them a string of trout in the evening. 



Below the mill, there were none of the unsightly beds of sawdust and mill rubbish 

 so frequently to be seen in Ontario streams. The tidal water from the Cumberland 

 straits came up the East river, then ascended the mill stream to the very foot of the 

 mill dam, and in returning carried away with it almost every particle of sawdust and 

 rubbish w'hich left the mill. 



In this stream, therefore, there could be no question about the ascent -of fish being 

 stopped by mill rubbish. It was all carried down stream and away out to sea. The 

 important question here was whether the ascent of anadromous fish was not stopped 

 by the mill dam. If they were thus stopped, they could not reach their natural spawn- 

 ing grounds above. In this case, one can easily see how the supply of fish is cut off at 

 its very source. My experiments and observations would seem to indicate that over- 

 fishing on the one hand, and mill dams with no proper fishways, on the other hand, are 



