628 
BULLETIN OF THE BUREAU OF FISHERIES 
greater than 80 meters. These differences may have been due to differences in verti- 
cal circulation around Cashes Ledge, however, as may the fact that the water was 
coldest here on bottom in 1915. 
In the western side of the eastern arm of the basin the differences in tempera- 
ture between the four summers were less than 1°. On German Bank the temperature 
was about 1° higher in 1914 than in 1913, but about the same as in 1915 (allowing 
for seasonal differences, due to the difference in date of the observations). 
The temperature along the northeastern coast of Maine, in the one side of the gulf, 
and in the deep bowl off Gloucester, in the other, have varied but little from summer 
to summer; but the deep water was 1° to 2° colder next the land west of Penobscot 
Bay and off Cape Elizabeth in 1914 than either in 1912 or in 1913. This also applies 
at depths greater than about 75 meters to the trough between Jeffreys Ledge and 
the coast. 
In the deep strata of the Bay of Fundy the bottom water ranged about 2° warmer 
in August, 1914 (Craigie, 1916a), than in the summers of 1915 (Craigie and Chase, 
1918) or 1916 (Vachon, 1918), and slightly warmer than Mavor (1923) records it for 
1917 or 1919. 
These annual differences may be summarized as follows: Except for the imme- 
diate surface, the upper 150 meters was slightly colder in the western, central, and 
northern parts of the gulf in 1914 than in either of the two preceding years, but the 
bottom water of the western, northern, and eastern parts of the basin were warmer, 
with still higher temperatures in the western side in 1915. 
More or less fluctuation in summer temperature is to be expected in any partially 
inclosed basin as subject to violent climatic changes as is the Gulf of Maine, and 
where waters of different temperatures meet. What really deserves emphasis is that 
the yearly changes have been very small during the period of record; certainly not 
enough seriously to affect the waters of the gulf as a biologic environment, except 
perhaps in 1916. 
During that year vernal warming proceeded so slowly in the sea, after an almost 
Arctic winter and a tardy spring, that the temperature of the central part of Massa- 
chusetts Bay was only 3.67° to 3.9° at 50 to 80 meters depth on July 19 (station 
10341), though the immediate surface was about as warm as the expectation for 
that date (16° to 17°). In fact, the deep readings were hardly warmer than read- 
ings taken in May of the preceding year, only about 1.5° warmer than the winter 
minimum for that level during 1913, and 2° warmer than the early March tempera- 
ture of 1920 (p. 522). The water off Northern Cape Cod (stations 10344 and 
10345) 38 was likewise decidedly colder in 1916 than in the summers of 1913 to 1915, 
with the 20 to 40 meter lever 2° to 3° colder than in 1913 and 6° to 9° colder than in the 
same month of 1914. The suprisingly low surface temperatures of 10° off Chatham and 
7.2° in the southwestern part of the basin on July 22, 1916, contrast with 16° to 17° 
for this part of the gulf as a whole at about that same date in 1913 and 1914. It 
is clear that such cold surface water reflected some temporarily and locally active 
vertical circulation, because the vertical range of temperature was less than 1° between 
the surface and 30 meters at the coldest of these two stations (10346), instead of a 
range of about 9°, which previous experience suggests as normal for the western side 
3J About 4.1° at 50 meters, 3.85° at 100 meters, and warming fractionally below that level to 4.06 at 150 meters. 
