CHAPTER XXVIII 



EGGS AND FEY OF THE HEEEING 



Sjy awning 



Herrings were first propagated in captivity in America in 

 the year 1878.^ A female of average size produces between 

 20,000 and 47,000 eggs, and the average is approximately 

 30,000. The eggs vary from one-thirty-third to one-twentieth 

 inch in diameter.^ They are deposited on the bottom. They 

 are ' covered with a glutinous material which soon hardens in 

 contact with the water ', and so they become attached to plants, 

 or stones, or gravel, or any other substance with which they 

 happen to come into contact — sometimes in bunches as big as 

 walnuts, or larger. The period of incubation discovered by the 

 Americans, from averages based on the handling of very large 

 numbers of eggs, is about forty days at 33° F. and about eleven 

 or twelve days at 55° F. Meyer's laboratory experiments in 

 1874, in Germany, gave about forty days at 38° F., and about 

 eight days at 58° F. 



The Americans found that sudden and extreme variations 

 between 33° F. and 53° F. had no harmful effect on the eggs ; 

 they merely retarded or hurried the hatching. But when eggs 

 were hatched at a temperature below 33° F., many of the larvae 

 were deformed — and a deformed fish larva always dies very 

 quickly. The sea temperature at a depth of 50 fathoms on this 

 side of the Atlantic does not fall so low as 32° F. until one is 

 well north of Iceland, and round the British coast it is between 

 46° F. and 50° F. On the main herring spawning-ground to the 

 south-west of Norway it is between 46° F. and 42° F. The 

 danger of the eggs suffering from the effects of cold on this side 

 of the Atlantic is accordingly much more remote than on the 

 American side, where the 32° F. line at 50 fathoms passes well 

 south of Newfoundland, westward towards the Nova Scotian 

 shore.s 



^ Cf . Mnmial of Fish Culture, p. 226-7 ; British Food Fishes, p. 455 ; Migra- 

 tions of Fish. 



2 Herring eggs with a diameter of 0-035 and 0039 inch run respectively 

 1,578,000 and 1,150,000 to the quart. The Norwegian eggs run 347,000 to the 

 quart with a diameter of 0-058 inch. In America the average is 541,000 to the 

 quart (average diameter 0-050 inch). 



a Cf. p. 187 below (fig. 20). 



