34 Transactions. 



a good deal here. It was found that in cold weather tish were 

 later in spawning than in mild weather ; that during a hai'd frost 

 they spawned very tardily ; and when there was a mild rain and 

 rapid thaw, they spawned more freely than under any other 

 circumstances. If it were taken from ice-cold water and placed 

 in a tank in-doors, the inflowing stream of wliicli was gradually 

 warmed, a tish from which it had been found impossible to take 

 ova would then yield its eggs freely. Some time ago, when 

 seeking salmon ova in the Nith, I could tind no ripe fisli ; but I 

 was told by some fishermen that there were plenty to be got in the 

 Cluden, which I found to be the case. I instituted some experi- 

 ments, in which Mr Rutherford of Jardington and some others 

 kindly helped me. We had thermometers placed in the two 

 streams ; and found, as I expected, that the temperature of the 

 Cluden was higher than that of the Nith. It has been said that 

 the temperature of the sea being colder than that of the rivers, 

 the fish left it seeking a higher temperature. I have not noticed 

 this so much myself ; but it is the experience of some writers, 

 and is recorded in the Government fishery reports and elsewhere. 

 But this I know, that the temperature of the sea during the late 

 spring months and in summer was often a great deal higher than 

 the temperature of the water in the river, very often varying ten 

 degrees or more ; and we found — a thing which had puzzled 

 naturalists — that salmon leave the sea and run up the rivers at 

 all times of the year, more or less. Why should fish run up the 

 rivers during the summer months, when the spawning season was 

 so far distant *? Seeing what an effect temperature had upon the 

 spawning of fish, I suggest that its effect on the reproductive 

 organs might compel them to leave the warmer waters of the sea 

 and take refuge in the rivers. Of course these were the best fish 

 — what we call the clean run fish. When the water of the sea 

 was of a low temperature, as in early spring, we did not get such 

 a large run of fish as we did later on. In the month of March, 

 for example, when the east winds are blowing, the fish do not run 

 so well as in April ; and they don't run so well in April as in 

 May. When I was at Douglas Hall I noticed this particularly. 

 So much was it the case that the tacksmen did not find it 

 remunerative to put on the net for a month after the opening of 

 the legal fishing season. But later on, when the sea got warmer, 

 they found a good many fish running. If the weather remained 

 cold, and the temperature of the sea at a low point, there was not 



