62 THE SEA FISHERIES 



speaking, about 2| million kilograms of plaice were captured every 

 year by German fishermen in the North Sea. This is equivalent 

 to 2460 tons. The number of plaice is estimated to be about 14 

 millions, and their length varies from 6| to z8 in. The age of the 

 individual fish ranges from two to twenty-five years, and the 

 average weight is 6-3 oz. Of these plaice nearly one-half the total 

 number — ^i.e. 7 millions — and nearly one-third the weight are so- 

 called undersized fish. They are all under 10 in. in length, and 

 under three and a half years old. Only 3 per cent of the plaice 

 caught by German fishermen are over 14 in. long and five years old. 

 The German investigators assert that in order to catch these 14 

 million fish for the markets a very large number of still smaller 

 plaice from 4 to 8 in. long are taken in the trawl nets and hauled 

 on to the trawlers' decks. These small fish are not landed in the 

 markets, since they are too small to be marketable, but they are 

 probably either dead or dying before they are returned to the sea. 

 At the very lowest calculation not less than from 28 to 30 million 

 young plaice are thus destroyed by German fishermen alone in the 

 North Sea every year. These figures are sufficiently alarming even 

 taken by themselves, but if the calculations be extended to include 

 the plaice taken from the North Sea by English and Scottish fisher- 

 men, then the total amount of destruction becomes truly appalling. 

 In 1913 no less than 237,183 cwt. of small plaice were landed in 

 England and Wales, and of these 215,380 cwt. were landed on the 

 east coast. The " small " plaice landed by the English trawlers 

 certainly number not less than 100 million individuals, and to catch 

 these in all probability another 400 million undersized and un- 

 marketable plaice are destroyed. The total quantity of flat-fish 

 taken from the North Sea by all countries (except Norway) was 

 estimated in 1903 to be 80,000 tons, and of this 67-2 per cent was 

 plaice. 



Another method of attacking the problem of overfishing, whether 

 applied to one species only or to fish generally, is to take the statistics 

 of trawled fish landed at a given market during a period of years, 

 having regard to the place and season of capture. This has been 

 done for the port of Aberdeen by D'Arcy Thompson. In his first 

 paper tables were introduced classifying the whole catch of trawled 

 fish in Aberdeen market during the three years 1905-7, according 

 to the regions from which it was derived ; the regions chosen for 

 this purpose being the northern, east coast, middle and south- 

 eastern grounds of the North Sea, the west coast fishing grounds 

 and Faroe and Iceland. As the other Scottish trawlers, fishing 

 from the ports of Leith and Granton, Dundee and Montrose, never 

 go beyond the North Sea and seldom very far from port, we have 



