- 6s - 



ships together, a size-limit of 22 cm. would, with the presumed fishing coefficient one- 

 third, suffice to give a large extra profit. For the German steamers a 26 cm. limit 

 would mean compensation for the loss, and 25 cm. a considerable profit; for the Ger- 

 man sailing vessels a limit of 23 cm. would, with fishing coefficient one-third, be enough 

 to give a considerable extra profit. 



The calculation here given as to the possible profits to accrue to the fishery owing 

 to the introduction of effective protection of the young plaice are based upon the sup- 

 position, that all plaice below the size-limit, which are now caught by the trawl will, for 

 the future, really be spared, and grow larger. This sujDposition can however, never be 

 entirely correct; even with the highest possible degree of protection which can be ob- 

 tained by the absence of the trawlers from the young-fish grounds, there will still always 

 be a certain number of undersized plaice caught and destroyed. But with a lower degree 

 of real protection, the profits of the fishery will also be proportionally less; if for in- 

 stance only half of all the undersized plaice formerly caught are now spared, then the 

 increase or profit in fish of legally marketable size will also only be half so great. The 

 profits calculated above are thus to be regarded as maximal values, with a fishing coef- 

 ficient of 0.33. 



On the other hand, the profit accrueing to the fishery by protection of undersized 

 plaice can be further increased, viz, by increasing the fishing coefficient: i. e., a more 

 intensive fishing than hitherto of plaice above the size-limit. This part of the stock 

 being larger than previously, it can bear more intensive fishing. With an original fishing 

 coefficient of 0.33, this stock will increase, after the introduction of protective measures, 

 by one-third, i. e., will amount to */;; its former size. And if the fishery formerly redu- 

 ced it by one-third, i. e., brought it down to Vs of its amount, it can now be reduced 

 by fishery from */:'. to ^/.-i, i. e., by one-half, without falling below its former size. This 

 possible increase of degree in the fishing can to a certain extent compensate for the 

 decrease in profit caused by imperfect protection. It could, however, if carried beyond 

 the extent permissible, also cancel the whole profit, by gradually reducing the stock of 

 legally marketable fish below the size at which it stood before the introduction of pro- 

 tective measures. 



Although these estimates of possible profit to the fishery, based as they are to a 

 great extent upon hypotheses, may appear uncertain, as against a certain loss, they yet 

 suffice to prove that an actual, certain profit may be reckoned with in the future, and 

 that this profit will be the greater, the more effectively the undersized plaice are pro- 

 tected. And protection will be easier, the more a size-limit succeeds in restricting the 

 ruinous trawling on the young-fish grounds, and the more the trawling, as far as it is 

 solely or chiefly concerned with plaice fishing, can be replaced by other and more 

 merciful methods of fishing. 



Besides the certain profit which the fishery would obtain from the enforcement of 

 effective protective measures, there is also a probable profit. An increase in the num- 

 bers of that part of the stock lying above the size-limit would mean an increase in the 

 number of females reaching maturity, and thus, unless the whole of this increase were 

 again removed by increased fishing, the number of eggs spawned would also be greater. 

 Other conditions remaining unchanged, this would lead to an increase in the stock of 



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