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(see p. 25) as 112.5 million fish, with a total weight of 29 million kg. Of these 

 the quantity under 25 cm. amounts to 32 "/o of the number and 14 "/o of the weight, 

 or 3Ö million fish, with a total weight of 4 million kg. the average weight being 1 1 1 

 gr. per plaice. This represents the loss which the introduction of a size-limit of 25 cm. 

 would entail. There remain 68 "jo of the number and 86 "jo of the weight, i. e., 76.5 

 million plaice with a total weight of 25 million kg. and an average weight of 327 gr. 

 per fish. As a consequence of the increase in the stock of plaice of 25 cm. and 

 upwards, efifected by the size-limit, according to our previous estimate, this quantity 

 would be magnified by one-third of its amount. The catch of plaice of 25 cm. and 

 upwards would then be increased by 25.5 million fish, weighing 8.3 million kg. which 

 represents the profit accrueing to the fishery some time after the introduction of the 

 protective measures. We see, that the profit in weight is more than double the loss, 

 it would however, in value probably be three times that amount, since a kilogramme of 

 plaice with an average weight of 327 gr. has at any rate a considerably higher market 

 value than a kilogramme of plaice with an average weight of only in gr. 



The same calculation worked out for the total landings in Germany (steamer and 

 sailing ship) shows an annual loss of about 6.6 million fish, with a total weight of 0.77 

 million kg. and an average weight per plaice of 117 gr. The profit would be 2.5 

 million fish, with a total weight of 0.57 million kg. and an average weight per plaice 

 of 230 gr. The loss is here greater in number and weight, but probably not in value, 

 as according to JOHANSEN's calculation for instance, plaice of an average weight of 230 

 gr. have in Denmark nearly three times the market value of those which average 

 117 gr. 



For the German sailing vessels alone, a size-limit of 25 cm. would mean a loss of 

 4.5 million plaice with a total weight of 0.5 million kg. and an average weight of in 

 gr. as against a profit of 0.8 million fish with a total weight of 0.16 million kg. and 

 an average weight of 196 gr., thus amounting to only one-third of the loss in weight. 

 This heavy loss would however in all probability be for the most part compensated by 

 the higher price. Almost the same applies to the Dutch and Belgian plaice fishery from 

 steamers and sailing vessels, while in the case of the plaice fishing from sailing vessels 

 of these countries, the loss occasioned by a size-limit of 25 cm. would scarcely be com- 

 pensated by the possible profit, at any rate at first. 



It appears, that in thus calculating the profit which should accrue to the fishery 

 by protection of the young of the plaice, the relative height of this profit in number 

 and weight per cent is entirely independent of the height of the size-limit, and only 

 depends on the intensity of the fishing to which that part of the stock now protected has 

 hitherto been subjected; being equivalent to the fishing coefficient of same. If this is 

 for instance one-third, then the profit to be expected is also one-third of the number 

 and weight of those plaice hitherto caught, from the size-limit upwards. If the profit 

 thus obtained is greater than the loss, then we have an actual extra profit. The loss 

 in weight is thus equal to the weight percentage of plaice below the size-limit, the 

 profit being equal to the weight percentage of plaice from the size-limit upwards, multi- 

 tiplied by the fishing coefficient. In this manner we can, with the view here given 

 (p. 6) of the loss, easily calculate what size-limit must be chosen in order to provide 

 a further extra profit. For the Dutch fishery for instance, — steamers and sailing 



