THE SEVERN SALMON. 223 



and live on the stock of fat they have laid in while at sea. It has 

 been computed that every female Salmon deposits about 900 eggs 

 for every pound of its weight, and that only 900 of these in every 

 17,000 shed in British rivers ever attain the parr stage. As 

 might be anticipated, eggs deposited in a running stream are very 

 liable to be carried away by the current, and, as I shall presently 

 show, the places selected by Salmon for their redds are precisely 

 the localities where Trout have previously deposited their eggs, 

 which now become routed up and carried away down stream to be 

 devoured by every hungry fish. 



The length of time the eggs remain in their nest before they 

 are hatched may now be considered. This is subject to variation 

 as great as from 50 to 128 days, which last period occurred at 

 Stormontfield on the occasion of a very severe winter. Acting 

 upon previous experience, Mr. Youl succeeded in transmitting 

 Salmon-eggs to the Antipodes in small boxes packed in ice, which 

 retarded hatching until the 145th day. Mr. Branden examined a 

 redd that appeared to have been left dry, but on opening it found 

 that a little water was trickling through the stones and gravel, 

 which was sufficient to keep the ova healthy. Having scraped a 

 hole he obtained a considerable number of eggs, and these he 

 transferred to a pail of water, where two-thirds hatched within 

 periods varying from five minutes to twenty-four hours. About 

 a week subsequently he returned to the same spot, and had 

 another dig for Salmon -eggs, no rise having occurred in the river 

 during the interval. He collected more, and putting them into 

 the water they hatched, as the former ones had done. He very 

 fairly suggests that this may be a wise provision to prevent ova 

 deposited in localities where the depth of the stream is liable to 

 considerable fluctuations from becoming lost or destroyed, which 

 must occur unless some delay be provided for ; for as the floods 

 come and sweep up these redds, the imprisoned ova are let 

 loose at a time when they are ready to burst and the young 

 to emerge. 



But Salmon-eggs, even in redds, are not permitted to rest in 

 peace and hatch in security : they have many accidents to escape 

 from and numerous enemies whose vigilance must be avoided. 

 Not only may floods prematurely sweep away redds with their 

 unripe eggs, but during the continuance of such high waters 

 spawning fish are unable to occupy their usual breeding grounds, 



