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IV. 

 The Introduction of protective measures for the plaice. 



/. to 4. The necessity of international protective measures. Protection by means of closing 



times, closed areas, or by prohibition of certain apparatus. Size-limits. Vitality of 



undersized plaice taken in the trawl. 



The General Report arrives at the following conclusions upon these points: 



1. Any protective measure against overfishing of the plaice stock and in parti- 

 cular against the imprudent and useless destruction of young plaice, can only be carried 

 into effect when based upon international co-operation and internationally enforced for 

 the whole of the North Sea. 



2. The international decreeing of close seasons and closed areas for the plaice is not 

 feasible out of regard to the capture of other sea fish which either do not need pro- 

 tection, or require to be protected at other times or in other places than the plaice. 



3. The international prohibition of certain implements of capture which have a 

 destructive effect on the plaice stock, e. g., the trawl, though in itself an effective 

 measure, can of course not be enforced until a new and less destructive implement has 

 been constructed. Were it only as regards the plaice and other flat fish, then such an 

 implement could be found in the Danish Snurrevaad, but for the present, and as far 

 as we are able to see, there can be no question save of an apparatus which can be 

 used for all bottom fishes alike, and this will, in all probability, always be a trawl in 

 some or another, more or less altered form. 



There remains then, as the only possible protective measure which can be discussed, 

 a size-limit for landing and sale, i. e., prohibition against landing or selling plaice under 

 a certain length. The countries in question are unanimously agreed as to the necessity 

 of fixing such a size-hmit by international co-operation, and that moreover, at the 

 earliest possible date 



Such prohibition as to landing and sale of plaice under a certain length would, 

 however, — upon this point also all are agreed — not be the same as a prohibition 

 against capture, and can never become so, as long as the trawl and similar implements 

 remain in use in their present from. On the shore grounds these undersized plaice 

 will continue to be caught, and that in greater or less, but always considerable num- 

 bers, by the nets. If then, such size-limit is to be an effective protection for the under- 

 sized plaice, it is neccessary that the undersized fish caught can be returned alive and 

 unharmed to the water. 



The important question of how and to what extent this is possible has been care- 

 fully investigated in several countries. The results show, that with the method of 

 trawling at present in use, viz., hauls of from four to seven hours duration, most of 

 the plaice are dead when brought to the surface, or if alive, are at any rate not 

 capable of living long. This is not so much due to the duration of the haul as to the 

 fact that the pressure exerted when the net, full of fish, is drawn to the surface, kills 

 or severely injures the greater number of the plaice, especially the smaller fish, and at 



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