604 BULLETIN OF THE BUSEAU OF FISHEKIES 



it is earlier in the season, with the temperature lowest between the 100 and 150 meter 

 level, though with its precise gradient varying from summer to summer. 



Temperatures fractionally higher close to bottom than in the mid depths have 

 also been recorded at several stations in the deeper parts of the Bay of Fundy in the 

 smnmers of 1915, 1916, and 1919. Craigie and Chase (1918), for example, found 

 the water midway between Letite Passage and Grand Manan coldest (5.59°) at 55 to 

 110 meters and fractionally warmer (5.7°) at 137 meters and 208 meters (5.66°). 

 Vachon (1918) again found the bottom water slightly warmer than the mid-stratum 

 at Prince station 3, off the eastern end of Grand Manan, on July 24, 1916, and 

 Mavor (1923) records a similar gradient at this same locality on September 4, 

 1917 — from 5.94° at 125 meters to 6.15° at 150 meters and 6.06° at 175 meters. 

 However, the water was coldest there on bottom on August 25, 1916, and again 

 on August 26, 1919 (Vachon, 1918; Mavor, 1923), just as Craigie (1916a) recorded 

 it for August, 1914. 



TEMPERATURE GRADIENT ON THE OFFSHORE BANKS 



No serial observations have been taken in the Northern Channel between the 

 coastal bank off Cape Sable and Browns Bank in August; but a range of nearly 5.5° 

 there on July 25, 1914 (station 10229) between the temperature at the surface (1 1.44°) 

 and near bottom in 100 meters (5.96°) makes it likely that the contrast is still wider 

 at the onset of autumn. 



Our only late summer serial on Browns Bank (station 10228, July 24, 1914) 

 showed a vertical range of about 6.2° between the surface (14.72°) and the 40-meter 

 level (8.35°), v/ith the temperature then rising fractionally, with increasing depth, to 

 8.5° near bottom in 85 meters. The surface was also about 6° warmer than the bot- 

 tom at two Albatross stations^' on the western and southern slopes of this bank on 

 August 31 to September 1, 1883, in depths of 146 and 119 meters, as tabulated below: 



Temperatures on the slopes of Browns Bank, °C. 



' From TowDsend (1901). 



Values slightly lower here in 1883 than in 1914 probably reflect the difference to 

 be expected between warm and cool summers, and not a seasonal succession, because 

 there is every reason to expect higher temperatures here late in August than in July. 



The Eastern Channel was also about 6° warmer at the surface than at 40 meters 

 on July 24, 1914 (station 10227). 



The shoaler parts of Georges Bank correspond more nearly to the waters along 

 western Nova Scotia in the temperature gradient, with strong tidal currents, with 

 which every fisherman is familiar, responsible for a nearly homogeneous state of the 

 water over the parts of the banlc where they are most active. 



» Dredging stations 200S5 and 200GG (Townseud, 1901, pp. 393 and 394). • 



