NORTH SEA INVESTIGATIONS. 



377 



mature fish, and am convinced that percentage of immature at that 

 size during the spawning season is infinitesimal. 



A female of 19 inches was found to be immature, but this was 

 some months after the spawning season. 



Spaivning period. — From the middle of January to the end of 

 March, but some seem to spawn in April, and a few perhaps as late 

 as May. It seems probable that spawning also takes place to some 

 extent earlier in the winter, but of this I have not yet sufficient 

 vidence. 



Common sole {Solea vulgaris). 



From February to September 12th, chiefly during the spawning 



season. 



Ten inches appears to be the usual size at which the male 

 reaches maturity. 



Though, as appears above, a female may occasionally spawn at 

 10^ inches, I am convinced that comparatively few spawn at less 

 than 12 inches, and I have no evidence of immature fish at more 

 than 12 inches during the period of observation. 



Spawning period. — Ripe females begin to appear at the end of 

 April, and are abundant during May and June, which seems the 

 chief spawning time. They become scarcer during July, and spawn- 

 ing is practically over by the early part of August. 



Spent females begin to appear in the Humber at the beginning 

 of July, and become more numerous as the month goes on, and con- 

 tinue to abound during August and the early part of September. 



* Exact length, lOj inches. 



