CHAPTER XX 

 FISHES AND MANKIND (continued) 



Harvest of the sea. Dangers of over-fishing and possible remedies. Fishery 

 investigations. Methods of research. Pisciculture. Artificial propaga- 

 tion. Introduction of fishes into new countries. Angling. Improve- 

 ment of Salmon and Trout fishing. Pollution and hydro-electric 

 schemes. Fish diseases: Furunculosis, Saprolegnia, Salmon Disease. 

 Fish parasites: Sea Lice, Gill Maggots, Worms. Monstrosities. Varieties 

 of Goldfish. Fishes used in controlling disease. Aquaria. Fishes in 

 museums. 



Speaking in 1883 the late Professor Huxley said: "I believe that 

 the cod fishery, the herring fishery, the pilchard fishery, the 

 mackerel fishery, and probably all the great sea-fisheries are 

 inexhaustible; that is to say that nothing we do seriously aflfects 

 the numbers offish." In those days of trawling and lining from 

 sailing vessels this statement was probably true enough, but 

 with the advent of steam-trawling, and with the enormous 

 growth in the volume of fishing that followed, coupled with a 

 great increase in the destructiveness of fishing gear, conditions 

 were altogether changed, and apprehensions have arisen as 

 to whether the operations of mankind are not depleting the 

 stocks of fishes in the sea. Many authors have described this 

 great international asset as the "harvest of the sea," but it 

 must be remembered that the harvest gathered by the fisherman 

 is one that he has never sown, and that, although he may take 

 large quantities of fish from the sea, he does nothing towards 

 increasing or conserving the supply. As Dr. Jenkins has 

 pointed out, the present generation is the trustee for future 

 generations in the matter of preserving our species of fish and 

 of maintaining a reasonable supply of the same, and it is, 

 therefore, of great importance that this problem should receive 

 the attention of scientific men before irreparable damage is 

 done to the stocks. Much has been written concerning the 

 application of various branches of science to the fishing industry, 

 and in the following pages a brief account of some of the 

 problems awaiting solution and of the methods employed by 

 fishery investigators may be given. 



Even after many years of research, it is far from easy for 



402 



