158 BRITISH FISHERIES 



eggs produced annually by each female of some of 

 the species investigated : 1 



Turbot 8,600,000 



Cod . ..... 4,500,000 



Haddock ..... 450,000 



Whiting ..... 120,000 



Plaice ..... 300,000 



Flounder . . . . . 990,000 



Sole . . . . . 570,000 



Dab . . . . ... 105,600 



Herring ..... 31,000 



Skates, rays, dog-fishes . Few, a dozen or so 



Fulton estimated these values by weighing the 

 whole of the ovaries of a single fish, and then 

 weighing a small portion, and actually counting the 

 individual eggs contained in the latter. The 

 value so obtained was then multiplied by the 

 number representing the number of times the 

 fractional portion of the ovary counted was 

 contained in the total weight of both organs. 

 Obviously, the total number of eggs obtained can 

 only be an approximation to the number actually 

 present ; but the values obtained give a sufficiently 

 exact idea of the fecundity of the fish. 



As a general rule, most sea-fishes which are used 

 as food spawn in relatively deep water and at some 

 distance from land. It has been supposed that in 

 the case of most species a definite spawning migra- 

 tion takes place, and that the fishes congregate 



1 " Comparative Fecundity of Sea-fishes," Ninth Report, Scottish 

 Fishery Board, pt. Hi, p. 243, 1891, 



