462 ME. F. DAY ON THE BREEDING OF SALMON FEOM PARENTS 



On the other hand, Mr. E. Blanchard in 1S6G* observed that the ova " of the grilse 

 are always sensibly smaller than those of the adult Salmon." Livingston-Stone, 1877 f, 

 remarked that in American Trout (Salmo fontinalis) that reside in spring- water, winch is 

 equivalent to a diminished supply of food, smaller eggs are developed than in such as 

 reside in brooks. On the M'Cloud river % " it was noted, in 1878, that the parent 

 Salmon were unusually small, their average weight being under 8 lbs." This small size 

 was stated to be undoubtedly caused, in whole or in part, by the fishery at the canneries 

 of the Sacramento, where the 8-inch meshes of the innumerable drift-nets stopped all 

 the large Salmon, but let all the small ones through. The eggs when taken proved to 

 be at least one third smaller than those of most previous years, and the average number 

 of eggs to the fish was about 3500 against 4200 in the previous year. Livingston- 

 Stone in 1882 §, writing respecting the eggs of Salmo fontinalis, observes that those 

 from the small fish of the elevated rivulets are not so large as those of the finer breeds 

 from warmer streams, concluding that the ova of these last are fully twice as large as those 

 found in the race residing in mountain rivulets. From this period, observations have 

 been frequently recorded to show that the eggs of the Salmonoids undoubtedly differ in 

 size consequent upon certain physical causes ; hence the assertion that in this family " the 

 small size of the ova [in Brachymystax coregonoides, Giinth.] is of sufficient importance 

 to separate these fishes generically from Salmo" j| may be questionable, especially as the 

 typical specimens examined in London were only 18 and 21 inches respectively in 

 length. 



The following figures are all taken from examples in the Howietoun fisheries, unless 

 otherwise noted ; and in order to make the statement plainer, the eggs of the various 

 species or crosses of these fish are given : — 



Sal, ,io salar, 16 lbs. weight. General size of eggs 0-24 of an inch. 



„ ? „ „ from 0-25 to 0-30 „ 



„ small „ „ 0-20 



,, „ grilse reared in ponds „ from 0-20 to 0-22 „ 



„ trutta, small ,, „ ,, 0-175 to 0-18 „ 



„ levenensis (var.) 8 years old, from one pond, the general size .... 0-24 „ 



but some are 022, and a few 0-21. and in three or four 0-20 ,, 



,, ,, 7 years old. General size 0-19 „ 



„ 6 „ 0-18 to 0-19 



2 and 3 



,, fontinalis 4 



2 



Hybrid S. fontinalis, S. alpinus 2 



. . . 0-17 

 . . 0-18 

 . . 0-17 



. . . 0-14 

 0-13 to 0-15 



* ■ 1'uissons des Eaux Douces de la France,' p. 401. t ' Domesticated Trout,' 3rd edition. 



% Report of United States Fish Commission. 



^ Bulletin of the United States Fish Commission, ii. 1882, p. 11. 



|| Catal. Fishes Brit. Museum, vi. 1860, p. 103. 



