PHYSICAL OCEANOGRAPHY OP THE GULF OF MAINE 
585 
JULY AND AUGUST 
The vessels of the Bureau of Fisheries have taken a large number of observations 
within the gulf during the months of July and August since 1912. July and August 
temperatures have been recorded in various parts of the Bay of Fundy region under 
the auspices of the Biological Board of Canada over a series of years. 21 The tidal sur- 
vey of Canada (Dawson, 1905 and 1922) likewise has gathered a considerable body of 
thermal information for the Fundian region and along the Nova Scotian side of the 
open Gulf of Maine. With such a wealth of material available, the chief difficulty in 
establishing the normal midsummer state of the gulf has been to appraise the 
importance of the annual and sporadic fluctuations that confuse the record. 
Fig. 44.— Temperature profile running easterly from the basin off Cape Ann along the trough of the gulf to the Eastern 
Channel for June 25 and 26, 1915 
SURFACE 
As the result of continued warming by the sun, the surface of all parts of the 
gulf is considerably warmer in July and August than it is in June, in most years 
rising nearly to its maximum by the last week of July over most of the gulf. The 
graphs for Gloucester and Boothbay Harbors (figs. 29 and 30) show that in inclosed 
situations of this sort the surface water is warmest then, mirroring the air tempera- 
ture; but in the open waters outside warming continues slowly until well into 
August, depending on the weather, with the readings highest some time during the 
21 See Copeland (1912); Mavor, Craigie, and Detweiler (1916); Craigie (1916£and 1916a); Craigie and Chase (1918); Vaehon 
(1918); and Mavor (1923). 
