be largely dead when thrown overboardo This is damaging and we have 

 to decide whether the advantages of the protection overweigh this 

 damage. Therefore, table 16 shows the returns of a group of plaice 

 which as 1-year-olds had a strength of 1,000 when this group was 

 fished either with nets with a minimum mesh width of 55 millimeters 

 without a set minimum size (table 16a) or bv nets with a mesh width 

 of 88 millimeters and vdth a minimum size for plaice of 25 centimeters 

 (table 16b) o It appears that in the second case the returns are 

 somewhat smallero However, we have assumed that the plaice between 

 18 and 25 centimeters were not at all protected. We expect that 

 this will happen through the forcing of unprofitable operations on 

 the young fish grounds. If we assume that through the avoiding of 

 the young fish grounds only two-thirds of those undersized fish are 

 caught, which would be destroyed by an unlimited fishery with the 8 

 centimeter net, then it appears that the returns from the protected 

 fish stock are greater than the return from the unprotected stock 

 (table 16c). It is most likely that considerably more undersized 

 fish will be saved and that the financial returns will be even greatero 



The decline of returns, caused by a minimum size of 25 centi- 

 meters, Twill not be great enough to prevent profitable fishing 

 on the young plaice grounds. The fishing will be less profitable, 

 the labor of culling will certainly increase and fishermen with 

 seaworthy ships will prefer to avoid the grounds of undersized fish. 

 However, fishermen with smaller ships will have to stay in the 

 coastal zone and be satisfied with lower returns, undoubtedly 

 damaging the younger fish. It is, therefore, necessary to encourage 

 the eventual disappearance of these less seaworthy ships and let- 

 them be replaced by more seaworthy ships, preferably those of the 

 "cutter" typeo 



Although it is possible to give a reasonable protection with 

 a minimum size of 25 centimeters, considerable quantities of young 

 plaice will always be caught on most grounds in the TJorth Sea as 

 long as the trawl is being used. The trawl actually is undesirable 

 for the plaice fishery. The ideal gear for plaice is the seine 

 or Daniahi "snurrevaad". The results of the Danish fishery show 

 how profitable this type of fishing is. A healthy exploitation 

 of the plaice stock would occur by fishing with the seine from 

 "cutters"© Insofar as seining has to be done during the day and 

 ceases during bad weather, it will be best suited for the southern 

 part of the North Sea. For that reason most of our seine fishermen 

 prefer trawl fishing during the winter months o For the protection 

 of the young, however, this is not too damaging since fewer under- 

 sized fish are caught during the winter. Some trawl fishing will 

 remain since the "snurrevaad" cannot be used for the catching of sole, 



cce Sole« 



The available information does not show that the sole stock was 

 in danger. On the contrary, the catches increased. This was 

 probably not entirely due to more intensive fishing but could be 

 attributed also to an increase in the densityo It is possible 

 that the decline of the plaice influenced the increase of sole. 



