— 24 =^ 



the catch. We arrive thus at the estimate, that every year about 140 million young 

 plaice are taken by English fishing boats in the young-fish areas during the summer 

 months alone, i. e., from April to August, and of these about 20 million of the largest 

 fish are brought to market, while 120 million small and very small fish are uselessly 

 destroyed. It is obvious, that it would be of the greatest practical value if we could 

 succeed in putting a stop to such ruinous plaice fishery in the spring and summer months 

 by means of an international size-limit or any other effectual protective measures. 



In late autumn and winter, from November to March, the plaice landings from 

 the southern North Sea are, (with the exception of Area C3) not only absolutely con- 

 siderably smaller, but also far poorer in small and richer in large plaice. Most 

 of all, however, the comparison of scientific hauls with market samples from the 

 young-fish grounds shows, that only a relatively quite small quantity of very small 

 plaice are caught here in winter by the trawl and uselessly destroyed, scarcely one 

 fourth of the total market catch; which is nothing in comparison with twice or four 

 times the market catch in the summer. The great mass of the small and very small 

 plaice are here, on account of their hibernating in the ground, almost without impor- 

 tance for the trawl fishery, and the winter catches of the shallower coastal areas 

 resemble therefore in their composition the catches of the deeper regions farther out at 

 sea. The destruction of undersized plaice is therefore considerably less in winter^ and 

 the useless destruction of same extremely small. 



c. The landings of the whole year from the whole of the North Sea. 



If we consider the whole North Sea, to the extent to which it is fished by English 

 boats, as one single district, and combine all the monthly landings from this district, we 

 arrive at the total landings for the whole year. Knowledge on this point is of particular 

 value to the practical plaice question. The extensive English market measurements for 

 the period of three years from October 1905/ 1908 give us a picture of the composition 

 of these yearly landings which has proved, owing to the methodical checking, to be 

 very reliable. And it appears from this, that the landings of the three consecutive 

 years differ neither in quantity nor in composition. In spite of various slight differences 

 in the extent and working of the plaice fishery in these three years, they have had no 

 noticeable influence on the composition of the landings, rather, in all probability, an 

 equalisation has been the result: nor is there any evidence of increase or decrease of 

 the various size classes during this period. 



The graphical (Fig. 5) representation of the landings for the year 1906/07 might serve 

 as a clear view of the composition of the annual landings of plaice from first class English 

 vessels in the North Sea during the years from October 1905/08. In this figure is 

 shown, along the abscissa under each length in cm. also the corresponding average age 

 for this length-class, the figures being based upon numerous investigations with regard 

 to age. The brief description of the composition given thereunder states, for the most 

 part, the mean values from the two annual series 1906/07 and 1907/08. 



The average yearly landings by weight amount to 29 million kg., by number 112.5 



