DEVELOPMENT AND GROWTH OF SALMON-FRY. 5(55 



The fact of the young salmon propagating its kind while it is yet itself in 

 other respects in an immature condition, is certainly an extraordinary departure 

 from the ordinary laws of nature, so far, at least, as land animals are concerned. 

 From certain observed facts, however, there is reason to believe that the economy 

 of the class of fishes differs in this respect from that of land animals — a disparity 

 which, in consequence of the medium they inhabit, has hitherto escaped the ob- 

 servation of the naturalist. As the young of the other migratory species do not 

 quit the river during the first year, it is probable that they also observe a similar 

 economy to that of their more valuable congener. 



It has been generally supposed that the male salmon, during the spawning 

 season, assists the female in forming the spawning bed. This idea is, I think, 

 founded in error, as, during the whole course of my experience, I have never been 

 able to detect the male taking any share whatever in the more laborious portion 

 of these parental duties. The only part he performs, beyond the mere sexual 

 function, consists in the unwearied vigilance which he exhibits in protecting the 

 spawning-bed from the intrusion of rival males, all of which he assiduously en- 

 deavours to expel. The female, regardless of the occasional absence of the males 

 during these contests, and probably satisfied with the presence of the male parrs, 

 proceeds with her operations by throwing herself at intervals of a few minutes 

 upon her side, and while in that position, by the rapid action of her tail,^ she digs 

 a receptacle in the gravel for her ova, a portion of which she deposits, and, again 

 turning upon her side, she covers it up by a renewed action of the tail, — thus al- 

 ternately digging, depositing, and covering ova, until the process is completed b}^ the 

 laying of the whole mass, an operation which generally occupies three or four days. 

 In the course of these experiments, it has been ascertained that the milt of a single 

 male parr, whose entire weight may not exceed one and a-half ounce, is capable, 

 when confined in a small stream, of eflfectually impregnating all the ova of a very 

 large female salmon. On the spawn first quitting the body of the female, it is 

 found to be enveloped in a thin coating of viscous matter, which the action of the 

 water does not immediately destroy, but which continues to admit of a partial 

 adherence to the gravel at the bottom of the spawning-bed, where the ova receive 

 the necessary fecundation of the milt, and are afterwards covered with gravel by 

 the instinctive efforts of the female parent, in the manner above described. 



How long these ova will remain excluded from the body of the female, and 

 yet continue capable of receiving with effect the fecundating action of the milt, I 

 have not hitherto ascertained. I have, however, made several experiments on 



* I am aware it has been a matter of dispute amongst observers as to which of the two extremities 

 of the fish is employed in the formation of the spawning -bed. However, from late opportunities of obser- 

 vation, which rarely occur, owing to the turbid state of the river in the spawning season, I am now sa- 

 tisfied that it is by the action of the caudal extremity alone that the gravel is removed. 



