THE IMMATURE FISH QUESTION. 75 
coast are a little larger in average adult size than in the North 
Sea. On the other hand, Mr. Holt found some males immature at 
11 inches, and I have seen no immature males ; but since the testes 
are so small it is difficult to be certain that a male is immature. 
The difference is in any case slight: according to Mr. Holt the 
“iological limit’? of immaturity is 12 inches, according to my 
result 13 inches ; but to exclude all immature fish it would have to be 
13 and 14 inches respectively. 
Soles: January 1st to March 11th, 1893. 
MALES. FEMALES. 
Length. .| No. examined. 
Mature. Immature. Mature. Immature. 
6 inches (0) 0 0 0 0 
a ss 0 0 0 0 0 
Sis; 0 0 0 0 0 
SOE. 5 5 0 0 0 
IO = 5 3 0 0 2 
55 15 12 (0) 0 3 
2 3; 21 12 0 5 4 
SE 95 3 0 0 1 2 
14 8 0 0 8 0 
MD 35 3 1 0 2 0 
Gene, 1 0 0 al 0 
ily(9 0. 0 0 0 0 
61 | 33 0 iy Mal 
Total number examined ‘ ; 5. le 
Immature . é é B - 11=18 per cent. 
Mature males . : 5 - 383=54 $3 
Under 10 inches . : 5 oO —a5 > 
It is important to notice that only eleven of these fish were 
immature, 18 per cent. ; while among the sixty-one selected as the 
smallest obtainable, 54 per cent., more than half, were mature males. 
This shows how comparatively slight is the destruction of immature 
soles by deep sea trawlers on the south-west coasts. The smallest sole 
obtained was 9 inches long, but smaller specimens down to 8 inches 
have been seen on other occasions. Soles less than 8 inches long 
are not destroyed by deep sea trawlers landing fish at Plymouth. 
If the Conference limit of 10 inches were enforced it would mean 
throwing overboard much less than 8 per cent. in number of the 
soles taken. 
It seems, then, more important to ascertain whether soles less than 
9 inches long are destroyed, and if so how and where. A few are 
taken at Plymouth by the shrimp trawlers, but I have no statistics, 
