610 



BULLETIN OF THE BUREAU OF FISHEBIES 



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 ttfb 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 



Flo. 64.— Temperature of the northern part of the gulf at a depth of 40 meters, August 31 to September 11. 1915. The Bay 

 of Fundy temperature is for 1919, according to Mavor (1923) 



exception of the one station off Mount Desert Kock 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° ^' 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 



" The exception is station 10043 off Cape Cod, with a 100-meter temperature of ahout 0° on August 29, 1912. 



