108 



Part III. — Twentij-first Annual Report 



EXPLANATION OF PLATE I. 



Chart of the North Sea, showing the areas of different depths — (1) up to 20, 

 (2) between 20 and 30, (3) from 30 to 50, (4) from 50 to 100 fathoms, and (5) 

 over 100 fathoms. 



Hg. = Herring ; M. = Mackerel ; L. = Lythe ; S. = Sturgeon. 



The black spots show the localities where special trawlings have been made, 

 as follows : — 



L— August 31, September 4, 1900; IT.— 16-19 October, 1900; III.— May 15, 

 1901 ; IV.— May 16, 1901 ; V.— May 17, 1901 ; VI.— May 19-22, 1901; 

 VII.— December 11, 1901; VIII.— March 10, 1902; IX.— May 23-28, 

 1902; X.— May, June, 1902. 



