— 13 



APPENDIX F: HENKING 



The average for 1903 thus shows a very marked decrease from that of 1902; the 

 greater part of the decrease lies with the small plaice. How far it is really so, could only 

 be determined by extensive measurements. 



The curves showing the results of the catches are again extraordinarily similar in 

 both years, a fact which can only stand in relation to the special habits and habitats of 

 the plaice. The fluctuation in the catch of the small plaice is very considerable; the 

 curve rises rapidly from the minimum in February to the maximum in June to August 

 (Fig. 7, 8, p. 23). 



In addition, a smaller rise is noticeable in the late months of 1902, which has to be 

 referred to the circumstance, that an unmistakeable renewed abundance of the smaller 

 plaice occurred on many banks, e. g. Heligoland, Sylt outer ground, partly also the 

 Southern Mud Bank. The increase of large plaice occurs chiefly in the months of late 

 summer and autumn. 



13. Witch and lemon-sole (PI. cynoglossus mostly and microcephalus). The 

 average catch per day amounts to : 



1902 1903 



6' 17 pounds 4'34 pounds. 



The fluctuations in the quite insignificant catches are not in general sufficiently 

 distinct to require special illustration here. 



14. Dab (PI. limanda). The average catch per day amounts to: 



1902 1903 L 



10-44 pounds 6'03 pounds. i^ 



The catch varies but little, yet a distinct maximum lies about March — May, a mini-''- 

 mum in December to February. 



15. Halibut (Hippoglossus). This is an inhabitant of the colder regions ; the average 

 catch barely reaches a pound, a proof of its rarety in this region. It was taken, however, 

 somewhat more frequently in March — April of both years, but in still quite inconsiderable 

 quantities. 



16. Rays play no small role in the southern North Sea. The average catch 



amounted to: 



1902 1903 



42-05 pounds 42-28 pounds. 



A great agreement in the catches of the two years ! They agree also, in that the 



greatest catch was made in December (to February 1902), whilst a second increase occurred 



in June— July (Fig. 23, 24, p. 27). 



A number of other species, as angler, dog-fish, sturgeon, conger, need not be con- 

 sidered here, but the mackerel requires a few words. Mackerel are taken in all months 

 except January to March', and on all the banks from Borkum to Norderney, Southern 

 Mud Bank and along the coast as far as the Little Fisher Bank. 



?) Nevertheless, ca. 200 pounds of mackerel were landed from the Little Fisherbank in February 1902. 



