950 TRANSACTIONS LIVERPOOL BIOLOGICAL SOCIETY. 
Growth Rate of Plaice throughout the year in the Irish 
Sea and St. George’s Channel as deduced from 
Marking Experiments (1905-1910). 




Total Mean Rate of Thedvetiosl Cumulative 
No. of fish} Increase | Increase | Increase | Rate of growth 
Month. measured. | in length | in length per Increase from 
(inches). | (inches) month. per month to 
month month. 
(1) (2) (3) (4) (5) (6) 
October 5 0-55 0-110 0-110 
November 21 1-25 0-060 —0-050 
December 46 8-375 0-180 0-120 
January 16 1-45 0-090 — 0-090 0-0000 0-00007 
February 19 1-00 0-052 — 0-038 0-0090 0-00452 
March 19 3°875 0-204 0-152 0:0546 0-06177 
April 55 10-075 0-183 —0-021 0-1544 0-21770 
May 43 14-0 0-325 0-142 0-2881 0-50577 
June 23 24-125 1-049 0-724 0-4195 0-92346 
July 23 40-875 1-772 0-723 0-5029 1-42478 
August 27 43-80 1-622 — 0-150 0-5224 1-94410 
September 14 34-40 2-457 0-835 0-4613 240294 
October 9 20-125 2-236 — 0-221 0-3425 2-74467 
November 14 37-125 2°651 0-415 0-2046 2-95026 
December 19 52-025 2°737 0-086 0-0887 3°04112 
353 2-737 3-0480 



Column (3) is formed from column (2) by taking the means. 
Column (4) is formed by taking differences from column (3). 
The calculation of columns (5) and (6) is explained in the text. 
Column (1) gives the numbers of plaice measured 
in each month during the years 1905-1910, and 353 fish 
in all are dealt with. These are fish which have been 
recovered during the Octobers, Novembers, etc., of the 
years in question, and which had been liberated during 
the season of minimal growth, October-March. Column 
(2) represents the total increase in length of all the fish 
recovered in each month, and column (3) gives the mean 
increment of growth of the mean fish between the 
beginning of the season of minimal growth and the 
middle of the month of recapture. Column (4) represents 
the rate of increase per month; the figures are obtained 
