64 THE SEA FISHERIES 



is a question that must be put and answered separately for this 

 fish and that, and for this or that fishing ground, and the accuracy 

 of the answer depends on the length of the period under review, 

 and increases greatly with every year over which the statistical 

 enquiry is prolonged. In the case of some fish there is already 

 sufficient evidence to enable one to draw general conclusions. The 

 cod, for instance, shows no evidence of gradual decrease, whereas 

 the plaice exhibits a falling off of the most serious description. 

 Professor Thompson deals at length with the sizes of plaice in 

 Aberdeen market according to the various grades of market classi- 

 fication and for various locaUties of origin. It is proved that the 

 plaice from the near grounds, off the east coast of Scotland, are 

 smaller than those from any other grounds frequented by the 

 Aberdeen trawlers, but, nevertheless, larger than the average size 

 of plaice landed by the EngUsh trawlers at the great English markets. 

 In spite of the general expansion of the trawling industry the total 

 landings of plaice at Aberdeen were less than two-thirds as large 

 in 1911 as in 1905. The catch of large plaice fell to nearly one-fifth 

 of the amount in 1905, that of medium plaice to two-thirds, while 

 the landings of small (including extra small) plaice had trebled in 

 amount. These extra small plaice are landed in considerable 

 numbers at Aberdeen in the autumn months from grounds which 

 lie near the port. They have a median size of rather less than 8 in, 

 and over 90 per cent of them are undersized, that is below 10 in. 

 in length. They constitute from 8 to 9 per cent by weight of the 

 plaice landed at Aberdeen, but they only represent about 2-3 per 

 cent in value. On the other hand, they represent no less than 32-4 

 per cent of the whole number of plaice landed. The imposition of 

 a size limit of 10 in. would put a stop to the present autumn fishing 

 for " extra small plaice," and would exclude about 5 per cent of 

 the small plaice landed. The total loss to the Aberdeen market 

 would be about 3 per cent in value of plaice landed, and approxi- 

 mately about one-thousandth part of the gross value of the whole 

 catch of trawled fish. Prof. Thompson is strongly of opinion that 

 the destruction of these very small plaice is detrimental to the 

 Fishery, and that it yields no commensurate benefit to the trade. 



The operations of the Aberdeen trawlers prove that there is a 

 serious diminution of plaice on practically all the fishing groun<^, 

 in fact the supply is only maintained by an ever increasing slaughter 

 of immature fish. For statistical purposes the areas fished over by 

 these boats in the North Sea are divided into the northern grounds 

 north of 59° N. and east of 4 degrees W. ; east coast grounds along 

 the coast from the Orkneys to the Firth of Forth ; the middle 

 grounds of the North Sea south of 59 degrees ; and the south- 



