1896.] on Fish Culture. 49 



be let off during dry weather. In tliis way the streams can be kept 

 up to their proper limits. They need never run so low as they have 

 been accustomed to do. But we find that by impounding water the 

 floods are lessened, and therefore that great scouring process which 

 goes on in the streams, destroying both animal and vegetable life, is to 

 a great extent lessened, and everything living in the water has a very 

 much better chance of existence than it had before. 



The desired result cannot be obtained by making one simple dam 

 upon a stream. Take a river for instance : if we make a dam, as has 

 been suggested — and one or two places of the kind have been made up 

 at the head of the waters of some streams — when the water is let off 

 as compensation water it is found, in one case which I remember, 

 that when it has run eight miles, after being started as a roaring torrent 

 from the reservoir known as Lake Vyrnwy in Wales, the stream is 

 not very j3erceptibly affected. I believe that it was raised about one 

 inch ; but there are other tributaries coming in, and if there were 

 reservoirs on these other streams, and we had compensation water let 

 off from them, we should get a rise of several inches instead of only 

 one inch, and we should find that the result would be very beneficial. 



I remember an attempt being made to bring up sea fish by an 

 artificial spate at a place in Scotland, and it was eminently successful. 

 The landed proprietor there blocked up the outlet from one of tlie 

 lakes, and then when the salmon were waiting to come uj) the river 

 he let off the water from this impounded lake, and the consequence 

 was that he got a good run of fish. So successful was it, and so 

 pleased was he, that he very soon tried it again, but the second time 

 it was just as unsuccessful as the first time it had been successful. 

 The consequence was that they came to the conclusion that the fish 

 had found before that they had been deceived, that there had not 

 been really a spate, that it had not been raining at all ; and therefore 

 the next time they fought shy of it and would not come up. When I 

 came to make inquiry I could not find that there had been any fish 

 waiting to come up ; and when these artificial spates are made it is 

 necessary to be exceedingly careful to make them not only in the 

 right way but at the right time. In one instance water was let off 

 from a reservoir very near the bottom, the bank being, I think, some- 

 thing like eighty or ninety feet high. The water was let off at a 

 level very near the bottom of the reservoir. Now, if the water had 

 been let off from a level near the surface it would have been very 

 much more beneficial to the fish. The water low down in a reservoir 

 contains very much more matter in suspension, and it is of a very 

 different nature from the water on the surface; and so, for fish- 

 cultural purposes we must take the water from the surface of the 

 lake, or as near it as possible, and then we may expect the fish to 

 appreciate it and follow the spate. Sometimes the fish do not want to 

 go. Well, it is of no use to make a spate then. If the fish do not 

 want to run you may let off water, and you may do what you like, 

 but you cannot make them go. But in my experience, and I have 



Vol. XV. (No. 90.) " k 



