DESTRUCTION OF SMALL FISH 59 



must not forget the prodigious number of offspring 

 given to fish. The taking of immature fish is not in 

 itself uneconomic, unless by that means we so far 

 reduce the total number that the adult stock begins to 

 dwindle. Sardines are more valuable than their adult 

 form, the pilchard ; whitebait, mainly composed of 

 young sprats, with from i to 20 per cent, of young 

 herrings, fetch more in the market than the parent 

 form ; and so long as the adults exist in sufficient 

 number to keep up the stock of fry, sardine and 

 whitebait fishing is perfectly legitimate. 



But, assuming impoverishment from one or other or 

 all of the causes enumerated, we should ask what steps 

 can be taken to check it, especially as regards the 

 more valuable flat-fish. It is at this stage that scien- 

 tific knowledge becomes particularly important. At 

 least nine out of every ten Acts of restrictive legisla- 

 tion have been shown by experience to be futile, or to 

 have produced results absolutely different from those 

 anticipated. It is equally plain that the failure of 

 these attempts to interfere with the natural course 

 of events has been largely due to inadequate know- 

 ledge of the complicated factors which affect the 

 growth, multiplication, and distribution of fish, and of 

 the influence which particular modes of fishing exert 

 upon the sources of supply. 



Let us examine the first-mentioned cause of im- 

 poverishment, the destruction of the 'accumulated 

 stock.' This formula has been eagerly adopted by 

 some who hesitate to admit the existence of any form 

 of over-fishing. It implies that a state of equilibrium 

 is possible between the forces of destruction and the 

 forces of repair; that on virgin territory older indi- 

 viduals tend to accumulate beyond what is necessary 

 for the maintenance of the 'current stock'; and that 

 their removal entails no real injury to the supply. In 

 scientific terms this means that the average age of 



