CH. IX] THE PRODUCTIVITY OF THE SEA 197 



by the natural powers of reproduction and growth of the species 

 sought for by the fishermen. So two categories of fishery legis- 

 lation have gradually come into existence, one group of regulations 

 designed to prevent the possibility of dispute between different 

 classes of fishermen, and the other group intended to prevent the 

 serious depletion of the fishing grounds. With the former we 

 have nothing to do here, and we are only concerned wdth the 

 assumption on which the second is based. 



There have always been two opinions with regard to the 

 possibility of depleting a natural fishing ground. On the one hand 

 it is argued that the quantity of any one kind of fish in the sea 

 is so great, the individuals are so prolific, and the amount of 

 destruction by the natural enemies of the fish, and by physical 

 agencies, is so enormous, that anything that man can do, in the 

 way of further destruction by fishing operations, has no appreciable 

 effect on the numbers of fish on a fishing grounds On the other 

 hand it is argued that man's influence is much more powerful, 

 and both the fishery statistics, and the practical experience of 

 those engaged in the trade, agree in the conclusion that many 

 kinds of fish are now less abundant in the sea than was formerly 

 the case. 



Now one must remember that fishermen go to sea in order to 

 earn money. During the last half of the nineteenth century 

 there gradually arose an increased demand for fish food, as the 

 means of transport developed and as great centres of population 

 were placed in easy communication with the fishing ports. So a 

 gradually increasing exploitation of the older fishing grounds, such 

 as the North and Irish Seas, was developed under the stimulus of 

 this increasing demand for the produce of these areas. Every 

 year saw an increase in the number of fishing vessels, and then 

 towards the 'eighties and 'nineties great numbers of powerful 

 steam-trawling, drifting, and lining vessels w^ere built and 

 equipped for work in these waters. But it was soon found that 

 the catches of fish made in the North Sea between 1850 and 1880 

 were no longer possible, and the continued exploitation of the 



1 This was the position taken up about 1860-70 by Huxley, Spencer Walpole and 

 others. More recently it has been adopted by Macintosh. See Resources of the 

 Sea, Cambridge University Press, 1899. 



