94 NOTES ON A FISHING VOYAGE TO THE 



predominant size is several centimetres ahove, in the central parts of 

 the North Sea it is several centimetres helow that standard. 



In other words, whereas on the virgin grounds of the Barents Sea 

 the female plaice live to spawn many times, in the southern much- 

 fished region the majority at the present time do not live to spawn once. 



3. The number of rings on the otoliths indicate a remarkably slow 

 rate of growth and great age attained in this region as compared 

 with the North Sea. It also appears from these investigations that 

 " biological spring," and also the spawning season, is some three to five 

 months later than in the North Sea, viz. in mid summer. 



4. On this voyage the differences in the proportions of the sexes at 

 different sizes was striking. Up to a certain size (40-44 cm.) males 

 were in great excess ; after this, rapid diminution in their numbers 

 took place. 



In the North Sea the same two features have been found to occur, 

 and are connected respectively with the spawning habits of the species 

 and with earlier mortality of the male fish and its slower rate of 

 growth. 



5. Various evidence points to the existence of a spawning ground 

 somewhat to the westward of the bank where the fishing took place. 



Other Species. 



The few other species which occurred during this voyage were as 

 follows : — 



Dab {Plcuronectes limanda). 



Long Rough Dab {Hii^poglossoides platessoides). 



Halibut {Hippoglossus vulgaris). 



Cod {Gadus morrhua). 



Haddock (Gadus aeglejinus). 



Catfish (Anarrichas {minor ?) ). 



Greenland Shark (Laemargus microcefhalus). 



Starry Ray {Baia radiata). 



Lump-fish {Cyclopterus lun^ms). 



and Cgclopterus {Uumicrotremus) sjyinosus, Milll. 

 A Cottoid {GymnacantMis tricuspis). 



Dab {Pleuroncctes limanda). 



This species was of very rare occurrence in the area visited. Only 

 four were observed, all being large ; two of these measured 35 and 

 36 cm. respectively. On an otolith from the latter fish seventeen white 

 rings appear very clearly, tending to show that the rate of growth of 

 this species, like that of the plaice, is exceeding slow in these waters. 



