172 TRANSACTIONS LIVERPOOL BIOLOGICAL SOCIETY. 
(1) The Plaice population at the beginning of Summer. 
In June this is made up as follows :— 
13 to 16 centimetres long, about 1% 
1625. 45 e = 5 ee of all the plaice taken 
is; 21 Bi ae 5. ey, . in a six-inch mesh 
Oh Do Bs a yi eee trawl-net. 
Zs 6 Oo = fe ei LP A 
These plaice have been spawned to the north-east of the 
Isle of Man, or in St. George’s Channel. The eggs and larvae 
drift into shallow water and are reared there. The plaice 
inhabit the shallow-water nurseries in the Bays and Estuaries 
until they are about 20 cms. in length. 
(2) Age at which Migration begins. 
This is over two and less than three years as a rule. 
Plaice less than 20 cms. in length hardly migrate at all, that 
is, they do not move outside the 5-fathom line. Of 1,100 
plaice liberated in these experiments ¥ 
5 % were less than 19 cms. long 
i3-y,, 53 r,t Bae hte 
34% :, 21 S 
while 50 % were from 20 to 23 cms. long. 
Of the 280 plaice recaptured 
0 % were less than 19 cms. long 
iy, = 20 
9%, “ Die 
while 50 % were from 21 to 25 ems. long. 
Even in the month of liberation and that immediately 
after, that is, before the fish had had time to grow, hardly 
any plaice, of those marked which were less than 20 ems. 
were recaptured. The small plaice up to 20 ems. long 
off the Lancashire Coast are a practically stationary population 
partially hibernating in the winter months. 
long 
oO? 
