210 
largest fish obtained the reproductive organs are still fune- 
tional. The maximum size for the North Sea seems to be 
28 inches, for the Danish seas it is smaller, about 224 
inches. When the Iceland Plaice fisheries were first 
exploited, very large specimens—over 30 inches in some 
cases—were obtained. 
Migration and distribution.— Wherever the distribu- 
tion in space of the Plaice has been attentively studied it 
has been found that a very well marked segregation in 
respect of the size of the fish exists. There is a close 
correspondence between the size of the fish and the depth 
of the water at the bottom of which it is found. The size 
increases with the depth. The fish does not exist outside 
the hundred fathom line, and indeed practically all the 
fishing is carried on in seas varying from 20 to 50 fathoms 
in depth. 
Since only the larger individuals are functionally 
reproductive, it follows that the Plaice spawns only in 
deep water, and it is the case that the spawning grounds 
are always situated at some distance from the shore. 
These spawning grounds are usually very definitely 
located in any district. Thus on the Hast coast of Scot- 
land such areas occur in the North about 16 miles seaward 
from Moray Firth, and further South off St. Andrews Bay 
and the Firth of Forth. In the Danish seas the fish only 
spawns in the more open waters, such as in the eastern 
parts of the Kattegat, in the Belts and in the Baltic. In 
the [rish Sea the positions of some such spawning grounds 
have also been determined, and one notable area lies East 
from the South end of the Isle of Man in a depression 
having an average depth of about 23 fathoms and sur- 
rounded by water of 16-20 fathoms in depth. The bottom 
consists of soft bluish-black mud with an abundant fauna. 
Scrobicularia and T'urritella are very abundant, and the 
