178 



NORTH SEA INVESTIGATIONS. 



Lemon sole [Pleuronectes microcephalus) . 

 February to September, chiefly during the spawning season. 



It appears that the male may be mature at 6 inches. No smaller 

 specimens of either sex could be procured. 



I do not think that many females spawn at less than 12 inches, 

 though, as appears above, some spawn when only 10 inches in length. 



Spawning period. — Ripe females first appear in the latter part of 

 April ; they are abundant in May, more so in June and July. No 

 spent females were met with until the latter part of August, although 

 search was constantly made for them. Many fish are still spawning 

 in the early part of September. 



The protraction of the spawning period is evidently due to the 

 fact alluded to elsewhere (p. 368), that the ova of a single individual 

 are produced in successive crops in one season, separated from each 

 other by an unusually great interval of time. 



Halibut {Hippoglossus vulgaris). 



More of my material was derived from Iceland and Faroe than 

 from the North Sea. I know very little about the spawning period. 

 Parnell gives the spring for the coast of Scotland. Grimsby liners 

 seem to know very little of it, and are divided in opinion ; one of 

 my informants thought he had seen spawning fish in April, but the 

 general opinion seems to be that spawning does not take place until 

 autumn or early winter. Probably, since the halibut is mainly a line 

 fish, very few ripe females come under the notice of fishermen. 

 Ripe males seem to occur more or less at all seasons of the year. 



The only fully ripe female which I have seen occurred at the end 

 of April. Another female, with enlarged ovaries, was found to 

 * One of these recently spent. 



