XV111 



The superintendent of the Tweed reported that during the 

 greater part of January the rivers were frozen at many places, 

 which prevented the fish getting on to spawning ground, and 

 many had to spawn in deep holes. 



" As the fish could not spawn, the retention of the ova and 

 " milt was likely to cause inflammation of the ovaries, and the fish 

 " being unhealthy, were more susceptible to disease." 



" The frost broke twice, and there were a number of salmon, 

 " and no eddies for them, and they could not make their nests." 



" The winter began in November, and lasted till the beginning 

 " of February." 



" More severe frosts have been known, but it was the con- 

 '* tinuance." 



" The river w r as covered with ice in the winter. The frost 

 " began end of November, and lasted till April." (Ayr.) 



" Thinks the disease due to the long spells of frost, and the 

 " confining the fish in little pools." (Ayr.) 



" Owing to the frost the river was very low in December 1878, 

 " and spring of 1879, and there was less disease afterwards." 

 (Derwent.) 



" The frost reduced the quantity of water in the river." 

 (Derwent.) 



As regards the effect of frost, the following experiment is most 

 interesting: — Sergeant Nicholson reports that on the 16th of 

 January 1878 ,five fish, one of which had a small spot on the end of 

 its nose, were put into a pool in the Caldew. On the 19th two others 

 were put in, making seven in all. A hard frost set in, and on 

 the 4th of February four were found to be affected by the disease. 

 The effect of frost is more especially noticeable in the case of 

 female salmon. Generally speaking, the proportion of male fish 

 to females found dead is very large. 



Mr. Donaldson states : " In former years chiefly kippers were 

 " affected. This year the female fish were most affected. There 

 " were 22 females to one male among the fish buried." 



By the returns from the Tweed given in by Mr. List, it will be 

 seen that there were found dead between Berwick-on-Tweed and 

 Carbarn 548 females against 208 males. 



An angler well acquainted with the Tweed writes that, of the 

 fish which he examined, " not one had spawned. They were all 

 " female fish, and full of ripe eggs. I attribute this to the frozen 

 " state for many weeks of the spawning beds, which prevented 

 K their getting on them/' 



Among the salmonidas at my own fish-breeding establishment at 

 South Kensington, I find that the females will hold their ova — even 

 though quite ripe — for a very long time ; in fact it frequently occurs 

 that I am obliged to spawn them artificially, even though I have no 

 mate for them, knowing quite well that if I did not they would 

 die. 



It must be recollected that when the frost comes, not only 

 salmon, but other fish, are driven into the deep holes in the river, 

 thus tending to aggravate the effects of the next cause to be 

 mentioned, viz., overcrowding. 



