cport 



— XVII — HOEK- INTRODUCTORY 



work and the preparation of a report on its results could not be made in sufficient 

 time, however, to be published in the present General Report. 



When the Bureau had taken over the statistical work, Committee B, which, '«vestigations 



on the natural 



as already mentioned, was originall}' formed to work at the problem of overfishnig, history of the 



could then devote its attention entirely to the biology of the Pleuronectidse and p'»'" 



other fish taken with the trawl. Several reports, though preliminary in part, have 



already been made on the results of these investigations. These are shown partly 



in Appendix E of this General Report by Prof. Fr. Heincke, parth" in Appendix G 



by Dr. JoH. Hjort and Dr. C. G. Joh. Petersen. The "Preliminary report on 



the natural history of the plaice, based on the investigations of Committee B", 



sent in by Mr. W. Garstang, the convener of the Committee, is entirely devoted ^"'"""f' 



to this theme and is published as Appendix H of this General Report. To this 



is added as Appendix H', a special report by Dr. H. C. Redeke ("The distribution 



of the plaice on the Dutch coast"). These reports together form a valuable addition 



to our knowledge of this fish; neither of them, however, is to be regarded as 



completed. Mr. Garstang reports on the results of the experiments with marked 



fish, on the migrations of the plaice, which are divided by him specially into 



summer and winter migrations, on the intensity of the fishing, the rate of growth 



of the plaice, the experiments on the transplantation of the plaice, on the vitality 



of fishes taken with the trawl, and finally on the trawling experiments and the 



protection of iindersized fish. Briefly summarised, his results are as follows: 



From the experiments with marked plaice, it appears generally, in his opinion) 

 that the plaice of the eastern and southern parts of the North Sea show a fixed 

 southerly tendency in the winter months, which changes to a northward and 

 seaward tendency in the course of the spring and summer. On the other hand, 

 the tendency on the western side of the North Sea, north of latitude 53°, is distinct!}- 

 northerly in winter. 



With respect to the intensity of the fishery, it is clear from the experiments 

 with marked plaice, that this is much greater on the coastal grounds than on the 

 deep-sea grounds further from the coast. 



With regard to the rate of growth of the plaice, the experiments with marked 

 and recaught plaice give in general such different results, both for the various 

 sizes and the various grounds, that the further treatment of this problem must be 

 postponed for the present. 



The transplantation experiments have given important results, according to 

 Mr. Garstang. On the one hand, it appeared, that the plaice on the Horns Reef 

 ground are not able to attain their maximum increase of growth there; in his 

 opinion, their growth is stunted, probably because this region is overpopulated. 

 When these fish are transported, however, to the Dogger Bank which has a better 

 store of food, they increase rapidly and greath" in size; their rate of growth is 

 greatly increased. The advantage, which the fishery might reap from such a 

 transplantation when made on a large scale, is pointed out by Mr. Garstang. 



The results obtained by the experiments on the vitality of the fishes caught 

 by the trawl, seem to show, according to Mr. Garstang, that but few of the small 



