■ Il — LATER STAGES: PLEURONECTIDS 



in June and November and the other changes are rather of the type of its own con- 

 tiguous area B 4 . 



Area C 2 also shows maxima in June and December with two intervening minima, in 

 February and September. 



The remaining cur- Megrims, 



ves show little changes, 

 though usually with a 

 slight maximum in June. 



As a whole, the 

 curves are difficult to 

 interpret, and may not 

 in all cases express the 

 true seasonal changes. 



Only from the deep 

 water areas are there 

 sufficient quantities to 

 furnish reliable curves, 

 shewing distribution of 

 the megrim (Figure 6 and 

 App. Table 10). In F T , 

 from which are derived 

 the largest quantities of 

 this deep-water fish, there 

 is a very characteristic 

 curve with a pronounced 

 maximum in June and 

 a minimum in January. 

 There is a very slight 

 secondary maximum in 

 September but otherwise 

 the increase and decrease 

 are fairly regular. In 

 area D 3 , the curve has 

 a rather different char- 

 acter. The chief maxi- 

 mum is in September 

 with a secondary one in 

 January. Between these 

 two are two minima in 

 July and November. In 



the course ot six months commencing at zero in July the catch of this fish increases rapidly 

 and steadily to over 70 kilos per diem in September and thereafter falls at a still greater rate 

 till zero is again reached in November. During the winter the catch again increases up to 

 a maximum in January and falls again to February. To some extent the changes are reciprocal 



Megrims. 



Witches. 



Figure 6. Average catch of Megrims or Witches per day by Steam Trawlers, 

 in certain areas of the North Sea. (Mean of the 4 years 1906— 1909). 



