448 THE POPULAR SCIENCE MONTHLY. 



as tq be quite safe. It is a large number undoubtedly, but what does 

 it come to ? Not more than that of the herrings which may be con- 

 tained in one shoal, if it covers half a dozen square miles and shoals 

 of much larger size are on record. It is safe to say that, scattered 

 through tlie North Sea and the Atlantic, at one and the same time, there 

 must be scores of shoals, any one of which would go a long way toward 

 supplying the Avhole of man's consumption of herrings. I do not be- 

 lieve that all the herring-fleets taken together destroy five per cent, of 

 the total number of herrings in the sea in any year, and I see no reason 

 to swerve from the conviction my colleagues and I expressed in our 

 report, that their destructive operations are totally insignificant when 

 compared with those which, as a simple calculation shows, must regu- 

 larly and normally go on. 



Suppose that every mature female herring lays 10,000 eggs, that 

 the fish are not interfered with by man, and that their numbers remain 

 approximately the same year after year, it follows that 9,998 of the 

 progeny of every female must be destroyed before they reach maturity. 

 For, if more than two out of the 10,000 escape destruction, the number 

 of herrings will be proportionately increased. Or, in other words, if 

 the average strength of the shoals which visit a given locality is to 

 remain the same year by year, many thousand times the number con- 

 tained in those shoals must be annually destroyed. And how this 

 enormous amount of destruction is effected will be obvious to any one 

 who considers the operations of the fin-whales, the porpoises, the gan- 

 nets, the gulls, the codfish, and the dog-fish, which accompany the 

 shoals and perennially feast upon them ; to say nothing of the flat-fish, 

 which prey upon the newly-deposited spawn ; or of the mackerel, and 

 the innumerable smaller enemies which devour the fry in all stages of 

 their development. It is no uncommon thing to find five or six nay, 

 even ten or twelve herrings in the stomach of a codfish,* and in 1863 

 we calculated that the whole take of the great Scotch herring-fish- 

 eries is less than the number of herrings which would in all probability 

 have been consumed by the codfish captured in the same waters if they 

 had been left in the sea. f 



Man, in fact, is but one of a vast cooperative society of herring- 

 catchers, and, the larger the share he takes, the less there is for the rest 

 of the company. If man took none, the other shareholders would have 

 a larger dividend, and would thrive and multiply in proportion, but it 

 would come to pretty much the same thing to the herrings. 



* In his valuable "Report on the Salt-Water Fisheries of Norway" (187V), Professor 

 Sars expresses the belief that full-grown codfishes feed chiefly, if not exclusively, on her- 

 riags. 



f In 1879 rather more than 5,000,000 cod, ling, and hake, were taken by the Scottish 

 fishermen. Allowing each only two herrings a day, these fishes would have consumed more 

 than 3,500,000,000 of herrings in a year. As to the Norwegian fisheries, 20,000,000 cod- 

 fishes are said to be taken annually by the Loffodeu fishermen alone. 



