610 
BULLETIN OF THE BUREAU OF FISHERIES 
TEMPERATURE AT 100 METERS 
The 100-meter level has an especial interest as representative of the stratum usually 
coldest in the gulf in summer. Here the extremes of temperature so far recorded to 
the north of the Cape Cod-Cape Sable line late in summer have been 3.95° south of 
Cashes Ledge on August 23, 1914 (station 10255), and 10° near Lurcher Shoal in the 
first week of September, 1915 (station 10315). 
The western side of the gulf has proven cooler than the eastern at the 100-meter 
level. Thus, 100-meter readings as low as 4.4° to 5° have been recorded only to 
the west of the longitude of Mount Desert Island (long. 68° 30' W.), with the single 
exception of the one station off Mount Desert Rock on August 9. The fact that all 
but one of the 100-meter temperatures for August west of that longitude have been 
below 5.5° 31 is evidence that this side of the gulf is uniformly the cooler at this level, 
not merely so locally. 
The absolute values vary from year to year within narrow limits, so that the 
isotherm most graphically dividing the cold western area from the warm eastern 
area in any given summer may be 5°, 6°, or even 8°. In each August of record this 
critical curve, parting the gulf, has followed a characteristic S-like course (figs. 55 
and 56), with the warmest water following the eastern side of the basin around to 
31 The exception is station 10043 off Cape Cod, with a 100-meter temperature of about 6° on August 29, 1912. 
