234 SALMON DIGGING THEIR NESTS. 



into the gravel, and burrowing upwards and 

 downwards in it, the tail being used as a propel- 

 ling power, and the snout as an excavating one. 

 As soon as one fish gets tired, the other takes its 

 place. When one link or nest of the bed is deep 

 and large enough, the female enters it and deposits 

 the mature portion of her ova, or part of it, and 

 then retires. Forthwith the male takes her place 

 and exudes some of his milt upon the ova, thereby 

 impregnating them. This done, they proceed to dig 

 another nest, the gravel and sand excavated from 

 which covers the ova in the first nest made. This 

 process is continued, nest above nest being dug, 

 until the female has deposited all her ova. This is 

 not the work of one day : it may extend from two 

 or three to eight or ten, according to the size 

 and age of the fish, that is, according to the 

 quantity of ova to be deposited. The younger 

 and smaller the female fish, the fewer ova she has, 

 the sooner they will be all mature, and the more 

 rapidly they will be deposited, and the whole 

 process of digging the different nests of the narrow 

 longitudinal bed, and covering them in, be com- 

 pleted. Once covered in, the fish have no further 

 care for the spawn. They drop down into the next 

 deep pool, and there remain until they become 

 partly convalescent from the exhausting effects of 

 spawning. They are now " mended kelts," com- 

 mencing their voyage to the sea to recruit 



