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FISHERY BULLETIN OF THE FISH AND WILDLIFE SERVICE 



that summer, for the tidal currents run as strong 

 over the shoals and around them today as they 

 did of old. Also, while the transition in tempera- 

 ture from west to east off Nantucket is not as 

 abrupt at depths greater than 10 to 15 meters 

 as at the surface, the temperature averaged 

 10° to 12° lower in the southwestern part of the 

 basin of the Gulf in early September 1953, even 

 at 30 meters, than abreast of Martha's Vineyard 

 (table 23) . 



Table 23. — Temperatures at SO meters and at 45 to 50 

 meters off southern New England and in the southwestern 

 part of the basin of the Gulf of Maine, September 1-13, 

 1953 



[Temperatures In °F.) 



The Nantucket boundary thus seems still to 

 be a definite one for animals living within 10 to 15 

 meters of the surface and requiring summer tem- 

 peratures higher than about 64°, while the low 

 temperatures of the southwestern part of the Gulf 

 similarly hinder expansion toward the northeast 

 of animals that may be dependent on maximum 

 yearly temperatures upwards of say 55° to 60° F. 

 and that are restricted at the same time to depths 

 of 25 to 30 meters or more. But there is no 

 apparent reason why any animal, demersal or 

 pelagic, that ranges indifferently between 10 and 

 50 meters (as many do), and that thrives in 

 summer-autmnn temperatures down to say 55° 

 to 60°, should not now range freely between the 

 offing of southern New England and the south- 

 western part of the Gulf, though confined to a 

 narrower depth-zone in the Gulf. 



The possibilities of fauna] interchange between 

 the head of Buzzards Bay and Cape Cod Bay via 

 the Cape Cod Canal must also be borne in mind, 

 though we have no definite evidence as to the 

 role the canal may actually play in this regard. 



Autumnal progression 



In the western side of the Gulf, the surface was 

 at its warmest for the year at about the same 



time in 1953 (middle to late August) as in earlier 

 summers of record. 



No readings were taken in the Gulf in 1953 later 

 than the middle of September; consequently, 

 comparison of maximum temperatures for that 

 year with those for previous summers cannot be 

 extended to the underlying water, where maximum 

 temperatures are reached progressively later in 

 the season at increasing depths. The dispersal 

 of heat downward, by the increasingly active 

 vertical mixings that are characteristic of early 

 autumn, seems at first to have followed the same 

 schedule in 1953 as in earlier years, however; for 

 while the surface off Cape Ann (area A, fig. 16; 

 table 24) cooled, on the average, about 1.4° be- 

 tween mid-August and September 9-10, the 

 underlying waters down to 100 meters had mean- 

 time warmed by some 2.5° to 3.3°. Hence, it 

 may be assumed that when the maximum tem- 

 peratures of the year were reached at successive 

 depths, they were at least 2° to 3° higher in the 

 western part of the Gulf in 1953 than was usual 

 during the period 1912-26. Reduced to concrete 

 terms, the vertical equalization of temperature 

 characteristic of November, which took place at 

 about 48° at the mouth of Massachusetts Bay in 

 1912 (Bigelow 1927, p. 980, table 4, station 10047), 

 took place at about 50° to 51° there in the autumn 

 of 1953. No information is available, yet, as to 

 the autumnal progression of temperature for the 

 eastern side of the Gulf in 1953. 



Table 24. — Temperatures off Cape Ann in August and 

 September, 1963 



Winter 1953-54 



Data for the winter of 1953-54 are confined to 

 bathythermograph readings taken February 16- 

 22, by the Asterias of the Woods Hole Oceano- 

 graphic Institution, at a grid of 22 stations cover- 

 ing the Massachusetts Bay region. It is probable 

 that the temperature had risen fractionally above 

 the winter minimum by that time, for the mean 



