SCIENTIFIC TRAWLING 183 



gave information as to the state of the fish after a period 

 corresponding roughly to that which small plaice would 

 lie on the decks of a trawler before being returned to the 

 sea. It also enabled a comparison to be made between 

 the proportion surviving under these conditions and the 

 proportion which would survive if they were returned to 

 the sea at once. 



The measuring of fish was carried out systematically, 

 the total catches being measured on nearly all occasions. 

 Enormous numbers of fish were dealt with, the total for 

 the years 1902-9 being 610,139, of which 179,763 were 

 plaice, 50,658 haddock, and 379,718 other sorts. 



Transplantation experiments were conducted on a 

 considerable scale. Thirteen of these experiments, 

 dealing with 3942 fish, consisted in the transference of 

 plaice from the coastal grounds of the North Sea to the 

 southern parts of the Dogger. The experiments began 

 in 1904, and by the end of June 1909 nearly 1000 of 

 the plaice had been returned. The two most noteworthy 

 features of the growth in length of these recovered fishes 

 were the undoubted growth which was found to have 

 occurred on the Dogger during the winter months, and 

 the full confirmation of the high estimates of a year's 

 growth which had been derived from the first experi- 

 ments. This growth was found to be never less than 

 twice, and frequently from two and a half to three times, 

 that prevailing on the coastal grounds from which the 

 plaice were taken. The condition of the transplanted 

 plaice showed a steady improvement until August, a 

 slackening in September, and a marked increase in 

 October, these relations existing in both the first and 

 second years of liberty. The weight of the plaice 



