be protected by a high minimxmi size. On the other hand there are 

 many places inside the zones where large plaice may be caught without 

 destroying many younger ones. Those places, often the deeper gullies 

 and holes, can be fished by the coastal ships with only the protection 

 of a high minimum size. This would help the coastal fishermen. It is 

 reasonable to expect that they will preserve the young fish. If they 

 cannot do this with a minimum size, then the argument that their 

 interests have to be protected loses its value and one of the most 

 important arguments against closing would be lost. However, the 

 technical difficulties of control and the high expenses will remain 

 a serious argumento 



It has been recognized that, for plaice especially, the 

 protection in coastal zones will cause a decline in the rate of 

 growtho This has been stated already and it was noted that the 

 destruction of 26=year-old or-older plaice cannot be of advantage to 

 the fisheryo The thinning of the 0- and I- groups would be of advantage. 

 However, we have stated that for the retention of a sufficient egg 

 production it will be necessary to save the 0- and I- groups entirely 

 by a total mortality of 50 percent. These statements are seemingly 

 contradictory. However, if the older groups are fished less intensive- 

 lyp a sufficient egg production may be had with the thinning out of 

 the 0- and 1= groups. Table 15 illustrates this j it shows that it is 

 equally possible to retain the seune number of 4-year-old and-older 

 fish by thinning of the 0- and I- groups and partial protection of 

 the 11° and 111= groups as it is to afford complete protection for 

 the 0- and !=■ groups. 



The shrimp fishery is chiefly responsible for the catch of the 

 0- and I- groups o It would be very difficult to prevent the destruc- 

 tion of a (|uantity of plaice by the shrimp fishery and it will, 

 therefore, be a good thing if there is no objection against a not 

 too large reduction of these year groups, when it is possible to 

 give the older year groups a partial protection by a higher minimum 

 size. This destruction of the young plaice by the shrimp fishermen 

 should not become too large, however. It is, therefore, necessary 

 to forbid the landing of these plaioe so that the shrimpers will not 

 be stimulated to catch more small plaice than is unavoidable in 

 normal operation. 



Heincke (1913a) estimates in his report that a minimum size of 

 26 centimeters is necessary to make the fishing on young plaice 

 grounds uneconomicalo We believe that it will be sufficient to set 

 a size of 25 centimeters o This size will also be acceptable to the 

 coastal fishermeno 



This size does not correspond at all with the selection curves 

 of a net with cod-end meshes of 8 centimeters j such a net will 

 retain all plaice above 18 centimeters. Undersized plaice will thus 

 be caught which may not be landed and with the usual methods will 



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