86 



THE SEA FISHERIES 



If the weights be considered the results are even more striking 

 A combination of the results of aU the experiments shows the 

 average growth m weight of the transplanted fish one year from the 

 date of liberation amounts to 382 per cent of the original weight 

 bimilar fish on the inshore grounds only increase their weight bv 

 100 per cent m a year. ^ 



The transplanted plaice had thus increased their weight by about 

 3i times that which would have resulted from their normal growth 

 on the coastal grounds. The increase in weight of the transplanted 

 fish IS accompanied by a more than proportionate increase in value 

 since weights being equal, large plaice are more valuable than 

 small. According to estimates based on the prices for the principal 

 trade categories in England, at the end of one year from the date of 

 liberation the fish recaptured almost equal in value all those set 

 free, while those still at liberty are worth about 5^ times (565 per 

 cent) as much. On another estimate based on more detailed prices 

 obtained firom Denmark, a year's recaptures are worth 166 per cent, 

 and those remaining in the sea 993 per cent of the total value of all 

 the plaice originally transplanted. There is reason to believe that 

 had all the plaice dealt with remained on the coastal ground, 

 unmolested throughout the whole year, their value would have 

 increased to about 3-3 or 4-3 of their initial worth accordmg as 

 English graded prices or Danish detailed prices are considered. 

 Within two years of liberation the transplanted fish actually re- 

 turned were at least from two to three times as valuable as all those 

 liberated, and probably more. These estimates are only approxi- 

 mations and their acceptance is subject to certain qualifications ; 

 they are, nevertheless, based on trustworthy data and cannot be 

 ignored. The growth of the transplanted fish takes place most 

 rapidly in the summer months, but it is shown that on the Dogger 

 Bank a certain amount of growth occurs even in the winter, when 

 growth on the inshore grounds has practically ceased. A consider- 

 able proportion of the fish remain on the Bank for a year or more, 

 and these fish grow even more rapidly than those which wander 

 off it. The principal migration off the Bank takes place when the 

 fish become mature for the first time, and they are then found on 

 the spawning grounds, particularly on those off the Yorkshire 

 coast. As time goes on the transplanted fish gradually become 

 distributed over the different fishing grovmds of the central and 

 southern North Sea, particularly over those which lie to the south 

 and west of the Dogger Bank. These transplanting experiments, 

 though interesting as a scientific experiment, are hardly practicable 

 on a commercial scale. 



