much greater advantage. A modification of this proposal is, to fix a higher size-limit 

 for plaice brought dead to market, a lower one for those brought in alive. This would 

 especially be advocated in Denmark and Germany. 



VI. 



The probable influence which an efl'ective protection of undersized 



plaice and a more rational and more productive fishing would exercise 



on the maintenance of the plaice stock. 



It is comparatively easy to approximately determine the loss of plaice which the fishery 

 would suffer in the first instance by the introduction of a size-limit; it is however, very 

 difficult to estimate the compensation of this loss, and possible ultimate profit, which would 

 arise from effective protection of the young fish and consequent lasting improvement 

 of the plaice stock. Such compensation, sooner or later, for the initial loss, and a 

 possible ultimate gain must naturally, if at all possible, be guaranteed, if size-limits 

 are to be legally enforced. 



The general opinion on this point is, that such a guarantee can be given. Pro- 

 tection of the young undersized plaice means an increase in the reserve stock which 

 supplies the higher age-classes, and thus, caetens paribus, an increase in the number of 

 larger and older plaice, or in other words an increased density of such fish in the stock. 

 To what extent such increase might take place is shown by the following estimate: 



The total stock of plaice in the North Sea has been estimated above at about 

 1,500 million fish, of 12 cm and upwards in length and from the beginning of the 

 third year and upwards. Of these about yô ''/o, or 1,140 million are under 25 cm. 

 long, and 24 "/o, or 360 million 25 cm. long and upwards, up to the greatest length, 

 or for every 100 small plaice under 25 cm. long, 32 larger fish. Of this stock of plaice 

 about 33 "/o are caught, according to our estimate of the fishing coefficient, every year 

 by the trawl, and, presuming that this coefficient applies to plaice both under and over 

 25 cm. we get 376 million of the former and 119 million of the latter. If we could 

 succeed, by means of a size-limit of 25 cm., in really protecting all plaice under this 

 length, then there would be 376 million plaice every year, of from 12 to 24 cm. which, 

 instead of being caught as heretofore, and disappearing from the stock, would remain 

 alive and continue their growth. Some time after the introduction of the size-limit we 

 should thus have, for every too plaice thus spared, 32 which had grown larger, and 

 the stock of larger plaice would undergo a corresponding absolute increase in numbers, 

 i. e., in this case of about 119 million, or rising from 360 million to 480 million. With 

 a fishing coefficient of 7» 160 million marketable plaice of 25 cm. long and upwards 

 would be caught annually, instead of as formerly, 119 million, or one third more than 

 than heretofore. 



If we apply this estimate to the English plaice fishery, we get the following results. 

 The quantity of plaice annually landed in England from the North Sea can be taken 



