524 



BULLETlJSr OF THE BUEEAU OF FISHERIES 



down at the end of February depends on the precise locahty, on the state of the 

 weather during the few days preceding, and, locally, on the stage of the tide, a ques- 

 tion taken up in connection with the autumnal and winter cooling of Massachusetts 

 Bay (p. 649). Our March cruise of 1920 began a few days after the temperature had 

 passed its minimum for the year, the surface being fractionally warmer than the 

 deeper water; but the temperature was still so nearly uniform vertically that the 

 range was less than 1° in the upper 100 meters at most of the March stations within 

 the outer banks (figs. 2 to 11). Most of the individual stations also showed a 

 slight warming from the 20 to 40 meter level down to 100 meters, except in the sink 

 off Gloucester (station 20050), where the bottom water was fractionally the coldest. 

 Wherever the water was deeper than 100 meters a decided rise in temperature was 

 recorded from that level downward. Thus the temperature off Cape Ann (station 

 20049) was 2.6° higher at 200 meters than at 100, and from 1° to 3° warmer at 175 

 meters than at 100 elsewhere in the basin of the gulf. The highest temperatures 

 recorded inside Georges Bank during March, 1920, were at 150 to 250 meters, as fol- 



Temperature, Centigrade 



1° 2° 3° 4° 5° 6° T 8° 9° 10° 11° 12° 13° 14° 15° 16° 17° 18° 19° 



Fig. 2. — Vertical distribution of temperature in the inner part of Massachusetts Bay, March to August. A, March S, 1920 

 (station 20062); B, April 6, 1920 (station 20089); C, May 16, 1920 (station 20123); D, August 23, 1922 (station 10032); E, 

 August 23, 1922 (station 1084O); F, August 20, 1915 (station 10106) 



lows: Station 20049, 5.66° to 5.63° at 180 to 200 meters; station 20053, 5.39° at 225 

 meters; station 20054, 5.4° to 5.48° at 175 to 250 meters; station 20055, 5.59° at 220 

 meters; station 20081, 5.39° at 200 meters. Thus, generally speaking, the deepest 

 water of the gulf is the warmest and the superficial stratum the coldest at the begin- 

 nmg of the spring. A glance at the temperature sections (figs. 2 to 11) will show how 

 widely this differs from the summer state. 



TEMPERATURE AT 40 METERS 



It is probable that the narrow band of 0° to 1° water that skirts the whole coast 

 line from Massachusetts Bay to the Grand Manan Channel on the 40-meter chart 

 for February and March (fig. 12) reflects conditions as they existed at the sur- 

 face a week or 10 days earlier in the season. Eeadings higher than 1° everywhere 



