214 



BULLETIN OF THE BUREAU OF FISHERIES 



coast; but during the July and August cruise of 1914 we failed to find it at any 

 station in the southeastern part of the basin, in the eastern and northern channels, 

 on Georges or Browns banks, or near Cape Sable, indicating that at this season 

 the C. hyperboreus of the Gulf of Maine are entirely cut off from the more northerly 

 centers of abundance along the outer coast of Nova Scotia, though continuous with 

 them and drawing from them by immigration earlier in the year (p. 217). During De- 

 cember and January it occurred in the horizontal hauls in the western basin, off Penob- 

 scot Bay, off Mount Desert Island, and in the Fundy Deep in 1920 and 1921 (table, 

 p. 304); also at three stations off Gloucester in the winter of 1912-1913 (Bigelow, 

 1914a, p. 409); and Willey (1921) records it in some abundance in the mouth of the 

 St. Croix River from November to February during the winter of 1916-17, but not 

 in January, 1920, though two specimens were noted in a tow taken on the 25th of 

 March in that year. Unfortunately our November-January cruises have not 

 extended to the offshore banks. 



Thus, the geographical range of C. hyperboreus in the gulf narrows from the 

 sea shoreward in summer and expands offshore again at some time (just when remains 

 to be discovered) during autumn or winter. 



Numericallj' C. hyperboreus is never more than a minor element in the plankton 

 of the gulf, though its economic importance may be considerable because of its large 

 size. Thus the average percentage of C. hyperboreus at the stations where it was 

 detected in the vertical hauls was only about 4.5 per cent for March, 1920; 7 per 

 cent for April, 1920; 2 to 3 per cent for all the May stations; and 7 per cent for all 

 the June stations (see tables, pp. 297 and 299) . In July, 1915, it averaged 2}4 per cent 

 of three vertical hauls, and in 1913 about 1 per cent of two hauls (80 and 270 

 hyperboreus to 8,800 and 5,400 Jinmarchicus). In 1912 there was 1 hyperboreus 

 to 50 Jinmarchicus in a sample from one station (10023), and 6 hyperboreus among 

 thousands of Jinmarchicus in another (10040). On July 22, 1916 (station 10345) 

 only one specimen was detected in a preliminary survey of some thousands of cope- 

 pods and none at all at neighboring stations. Willey (1919), however, records 8 per 

 cent of hyperboreus near Eastport in August. In December, 1920, and January, 

 1921, it averaged 3.5 per cent at the stations where it occurred (table, p. 304) but only 

 about 1 per cent at all the stations combined. The maximum abundance of C. 

 hyperboreus is 45 per cent, but this is at a station where the total catch of copepods 

 of all kinds was extremely scanty (7,500 copepods per square meter off Gloucester 

 on April 9, 1920, station 20090). The vertical hauls for 1915 and 1920 afford only 

 eight instances of hyperboreus in percentages as great as 15 per cent. 



The numbers per square meter — counting only the stations at which it 

 occurred — are as follows: 



Date 



Average 



Maximum 



Minimum 



February, 1920 



March, 1920 



April, 1920 



May, 1915, and May, 1920 

 June, 1915 



583 



403 



804 



2,561 



1,634 



1,125 

 4,162 

 9,100 

 20, 575 

 6,450 



25 

 

 

 



25 



