104 EEPORT OF THE COUNCIL. 



plaice recovered in the March following liberation exceeded that of the 

 fish recaptured in the previous October by over 3 cm. (males 3"1 cm., 

 females 3*9 cm.) in the case of those recaptured on the Bank, and by 

 1"7 cm. in the case of all recoveries irrespective of position of capture. 

 The first year's growth in length is given in the following table : — 



Average growth in cm. during one year, draicn from the experiments of 190 4.-8. 



Total Recoveries. Recoveries on the Bank. 



Average Average 



Range of average of all years Range of average of all years 



during the period. combined, during the period, combined. 



Male ... ... 8-7-16-8 12-2 9-S-U-O ll'S 



Female ... ... 11-0-16-2 14-2 13-1-16-S 15-3 



Both sexes combined 9-5-15-4 13-3 lO-Q-lG'S U'S 



Where sufficient data exist for trustworthy comparisons, this growth 

 is 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. Only a few fish are available for an estimation of 

 growth during two years following liberation, but the growth for this 

 period appears to be about 20 cm. 



The condition of the transplanted plaice, as indicated by the relation 

 between the weight and the cube of the length of the fish, shows 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 retaken after 

 a year was found to have increased to from 4'5 to 5"75 times that 

 possessed on liberation : this increase is, in round terms, rather over 

 three and a half times the increment which would probably have 

 resulted in the same period on the coastal grounds. 



Since the value of plaice increases with their size, the increase in 

 value of the transplanted plaice is yet more remarkable. If the most 

 detailed statement of the prices of plaice of different lengths, those 

 drawn up by Johausen for plaice of the Kattegat, be accepted as 

 accurate for the North Sea, it would appear that these plaice when 

 transplanted had a value of £4: within a year £7 worth had been 

 recovered, while those presumably at liberty were of £42 value. Had 

 the plaice remained on the coastal ground, on the same calculation, 

 their total value at the end of the year, assuming none were retaken 

 during the year so that all enjoyed a year's growth, would be but £18. 

 The estimated increase in value in two years is based on more meagre 

 data. It indicates, however, that the value of the plaice retaken 

 within this period was nearly three and a half times (341 per cent) 

 that of all the plaice liberated, while the probable worth of those still 

 at liberty was still greater. 



