556 
BULLETIN OF THE BUREAU OF FISHERIES 
spring than this event is usually to be expected allowed a decided warming of the 
upper stratum to 2.8° to 3.5° from the Cape Sable slope out to Browns Bank, though 
with very little change from March to April on the Georges Bank side. 
MAY 
SURFACE 
From late April, on, the temperature of the western side of the gulf constantly 
rises, most rapidly at the surface, progressively slower with increasing depth. Near 
Cape Sable, in the eastern side, however, the vernal cycle is dependent on the vol- 
ume, temperature, and seasonal “time table” of the Nova Scotia current. Where 
Fig. 26. — Temperature profile running from the eastern part of Georges Bank, across the Eastern Channel, Brown’s Bank, 
and the Northern Channel, for April 15 and 16, 1920 
this debouches into the gulf the surface stratum is at its coldest some time in April 
or even as early as the last of March in “early” years (1919, for instance), but not 
until May in “late” years, as probably happened in 1920. Unfortunately, neither of 
our May*cruises (1915, 1920, or 1925), nor the ice patrols stations for 1919, has covered 
the gulf as a whole ; hence I can offer only a composite picture for the month, based on 
years that certainly differed considerably in the rate of vernal warming and in the 
date at which the chilling effect of the Nova Scotian current reached its maximum. 
On this basis the highest surface temperatures of early May (fig. 27) are to be 
expected in Massachusetts Bay, the lowest in the Cape Sable-German Bank region, 
with the whole area west of the longitude of Penobscot Bay warmer than 6° by the 
10th, if not earlier, contrasted with surface readings of about 3° or lower off western 
Nova Scotia. 15 
“Three degrees on German Bank, May 9, 1915 (station 10271); 2.7° there on Apr. 28, 1919 (ice patrol station No. 22) 
