r16 MARVELS OF FISH LIFE 
The young plaice are now nearly an inch in length, 
and gradually make their way toward the shore. Thou- 
sands may be caught in a shrimp net, and they are 
abundant in the pools left on the sandy shore by the re- 
ceding tide. The subsequent rate of growth, as in all fish, 
depends upon the food supply; for example, plaice grow 
much more rapidly on the Dogger Bank than on plaice 
grounds near the coast. As a fair average, a plaice is 
about three inches in length at the end of its first year, 
and in each successive year adds from two to three 
inches to its length until it is five years old, after which 
time the growth is not quite so rapid. 
Plaice usually spawn when five or six years old, 
ie. when they are from thirteen to fifteen inches in 
length. To know exactly at what age a fish spawns 
is of importance, for in the distant future, when 
sound legislation husbands our sea fisheries, it will 
be illegal to offer a fish for food supply until it has 
had opportunity of maintaining the continuance of 
its race. 
We have seen how the exact age of the salmon can 
be read by the rings of growth on its scales. The age 
of the plaice and other fish can be told by certain light 
and dark rings seen upon the ear stones or otoliths in 
the skull of the fish. Looking at the illustrations of 
otoliths it will be seen that there is a central white 
portion which indicates the growth of the otolith during 
the first spring and summer in the life of the fish. The 
autumn and winter growth is then indicated by a dark 
