654 BtTLLETIN OF THE B0KEAU OF FISHERIES 



1 From Mavor, 1923. ' Approximate. 



Apparently the waters along the western shores of Nova Scotia are about as cold 

 as the inner part of Massachusetts Bay in the first week in January, judging from 

 1921, when the temperature was uniformly 3.8° to 3.9°, surface to bottom, a few miles 

 off Yarmouth (station 10501) on the 4th; or about the same at the surface as the 

 reading off the mouth of Boston Harbor 5 days previous, with no wider difference at 

 20 to 40 meters than can be accounted for by more active vertical circulation and 

 by this difference in date. 



In the northeastern part of the trough, on January 5 (station 10502), the surface 

 was coldest (5.56°) overlying a uniform stratum (6.6° to 6.7°) at 40 to 100 meters, 

 with slightly warmer water (6.9° to 7.2°) at still greater depths; but readings taken 

 in the western side of the basin for January 9 showed the water about 2° warmer 

 at 100 to 150 meters than either the surface or the bottom (station 10503). 



Thus, the level that is coldest in the western side of the basin in summer is 

 warmest in midwinter^ — about 2.5° warmer, in fact (7.5° to 7.8°), than we have ever 

 found it in August. A serial for late November is required for a correct picture of 

 the autumnal change there; but the fact that the salinity of the 100-meter level was 

 higher at this locaUty in December, 1920, than we have ever found it in August, 

 September, or October (fig. 138), suggests that the temperature of its warm stratum 

 had been maintained at about the November value (about 8°) throughout December 

 by additions of warmer and more saline water from the southeastern part of the gulf, 

 whUe the surface stratum had cooled. This reconstruction is corroborated, also, by 

 the fact that while the surface continued to chill (about 0.5°) during the interval 

 between December 29 (station 10490) and January 9 (station 10503), the 100-meter 

 level warmed by about 0.5°, the 150-meter temperature rose by about 1.5° during 

 the interval, with no corresponding increase in salinity (p. 994). 



In horizontal projection the midwinter serials just discussed show the 40-meter 

 level coldest (3.86°) in the eastern side of the gulf, off Yarmouth, Nova Scotia; 4° 

 to 6° in Massachusetts Bay, along the coast of Maine east of Penobscot Bay, and at 

 the mouth of the Bay of Fundy; 6° to 7° elsewhere (fig. 80). The temperature 

 was regionally as uniform at 100 meters, also, varying only from 6.03° to 7.81° over 

 the whole area — coldest in the mouth of the Bay of Fundy. At 200 meters, how- 

 ever, the regional distribution of temperature (also of salinity — p. 804), was just the 

 reverse, being warmest (6.9° to 7°) in the northeastern branch of the basin and the 

 Bay of Fundy and coldest in the western side of the basin off Cape Ann (5.3° to 5.6°). 



No serial temperatures have been taken in the open basin of the gulf during the 

 last half of January or the first three weeks of February, but records for the vicinity 



