INTRODUCTION. 3 



industry in any way into line with other industries, a thorough 

 knowledge of the life-history, food, habits and diseases of the 

 food-iishes is essential. With this aim in view scientists con- 

 tinue to accumulate facts relating to these, and although to the 

 ordinary observer some of these facts may appear to be of no 

 economic importance, as not directly bearing upon the points at 

 issue, those more familiar with the progress of knowledge are 

 aware that at any time some discovery seemingly insignificant 

 in itself may throw a flood of light upon certain phenomena 

 in a way which may directly benefit the progress of the whole 

 industry. 



Historical Remarks. It is, as already indicated, little more 

 than a decade since the eggs and larval stages of almost all our 

 British food-fishes were unknown — at least so far as 'regards their 

 study by men of science in this country. For the discovery 

 of the fact that the eggs of the cod, haddock and gurnard are 

 pelagic, that is, float freely in the ocean, we are consequently 

 indebted to Prof G. O. Sars of Christiania, an able naturalist — 

 trained from boyhood under a distinguished father, and who 

 by a fortunate appointment to a fishery post in Norway was 

 enabled to make these and other important observations from 

 1864 onwards. 



Prof. Sars had gone in January of the year just mentioned 

 to examine the cod-fisheries of the Lofoten Islands, and had 

 watched enormous numbers of the fishes which come in to 

 spawn. Toward the end of February he observed the earliest 

 spawning. " By fishing with a fine net' on the surface of the 

 sea I caught some small, completely transparent globules, 

 floating on the water, which I at first took for some very low 

 species of aquatic animals, as I was entirely ignorant of the 

 peculiar spawning-process of the codfish, to which I shall now 

 refer. I had in former times heard fishermen say that the roe 

 of the codfish could be seen floating in the water, and that at 

 certain seasons it filled the sea to such an extent as to make 

 the water appear quite thick ; but as this was in direct opposi- 

 tion to anything I had hitherto known of the spawning of fish, 

 I could not but suppose that what had been taken for spawn 

 1 Quoted from U.S. Fish Commis. Eept. (for 1877), 1879. 



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