PHYSICAL OCEANOGRAPHY OE THE GULF OF MAINE 
625 
for which the exposure of the neighboring flats to the sun at low tide is no doubt 
responsible — with 13.2° at 18 meters off Plymouth (station 10642). In winter these 
same regions cool to 0° or even fractionally colder. Around the more exposed shores 
of Massachusetts Bay, however, we have found the bottom temperature 12° to 9.8° 
in 15 to 18 meters depth; 7° to 9.8° at 25 to 30 meters; 7.2° to 5.6° at 40 to 50 
meters; and 4.5° to 6.2° at 65 to 75 meters in August. 
Compare this with the Bay of Fundy, where even the littoral zone warms 
only slightly above 10° to 12° off open shores, but where the bottom in 40 to 50 
meters is almost equally warm by the end of the summer (p. 599). Under these con- 
ditions cool-water animals, at home in temperatures up to 10°, find no limit to their 
bathic dispersal short of the surface, instead of being confined to depths greater 
than 12 to 15 meters, as they are in Massachusetts Bay in summer. On the other 
Stations 
Fig. 66.— Temperature profile crossing the mouth of Massachusetts Bay from Gloucester to 
Cape Cod, August 22, 1922 (stations 10631 to 10633). The broken curve represents the 
shoalest contour of the bottom along the rim formed by Stellwagen Bank 
hand, any animal restricted physiologically to truly Arctic temperatures would find 
a more favorable habitat in the deeper parts of Massachusetts Bay and in the still 
colder trough off the Isles of Shoals than in the Bay of Fundy at any depth. 
The studies on the life history of the cod, on which the Bureau of Fisheries is 
now engaged, lend special interest to the bottom temperatures on the grounds where 
most of the fish have been tagged — Nantucket Shoals, Platts Bank, and the vicinity 
of Mount Desert Island. 
In August, 1925, the Halcyon had bottom readings of 11.2° to 15.56° on the 
shoals in depths of 20 to 30 meters (p. 1012), and probably this is about the maxi- 
mum to be expected there in an average summer. On the other hand, the bottom 
water cools to about 3° to 4° there at the end of winter, so that any fish (or other 
