298 



FISHERY BULLETIN OF THE FISH AND WILDLIFE SERVICE 



the months of January, February, October, No- 

 vember, and December. March and September 

 also show rather pronounced upward trends for 

 the latter part of the period. It will be noted 

 that temperatures at New Haven were, in general, 

 relatively cooler than at Eastport for the period 

 1875-1900 and relatively warmer for the periods 

 1901-25 and 1926-50. These differences in the 

 later years may reflect urban development at 

 New Haven. Figure 5 shows clearly that the 

 important changes in temperature occurred during 

 the fall and winter months. 



SEA SURFACE TEMPERATURES 



Trends in sea temperatures in the North 

 Atlantic north of latitude 55° have been reported 

 by Smed (1949, 1953b). Some records covering 

 periods of time sufficient to indicate significant 

 trends are available for the Atlantic coast. 

 Hachey and McLellan (1948) have publislied data 

 for St. Andrews, New Brunswick, for the period 

 1921-47. Annual means, with 12-month moving 

 averages of temperatures, are shown by Lauzier 

 (1952) for St. Andrews and for Sambro Lightship, 

 Nova Scotia, for the period 1936-51. 



Daily readings of surface temperature were 

 made at Boothbay Harbor, Maine, for the period 

 1905-49. These readings were made at 8 a. m., 

 12 noon, and 4 p. m., in conjunction witii the oper- 



ations of the fish hatchery there during that 

 period. The monthly means are presented in 

 appendix talkie 1, p. 344. Examination of the 

 original records indicates that these temperatures 

 (I'ccorded to the nearest degree) were carefully 

 taken for the most part; however, some tempera- 

 tures below the freezing point of sea water were 

 recorded. The trends and fluctuations in these 

 temperatures are in good agreement with those 

 appearing in the St. Andrews data (cf. figs. 6 

 and 7). 



Annual deviations from the 43-year mean at 

 Boothbay Harbor (1906-48) are shown in figure 

 6. There is only a slight increase in the annual 

 means over the period. For the 25 years, 1906-30, 

 the annual means average 45.9° F.; for the 18 

 years, 1931-48, the average is 46.4°. 



A striking melioration of winter conditions in 

 recent years is shown when the January-July 

 difference in water temperature at Boothbay 

 Harbor is plotted as a deviation from the mean 

 difference for the period of record (fig. 8). The 

 average January and July temperatures for various 

 periods are as follows; 



J 



r 



< 

 > . 



-2 



-3 



I I I I I I I I I I I 



1"""^- 



I ' ' ' I I 



X_L_ 



I I I I I I I I I I 



I I I I I I I 



1904 



1910 



I 920 



I 930 

 YEAR 



I 940 



950 



FidiRE 6. — .\iiiiual dt'viatioii.s from the mean surface temperatures, 1906 to 

 1948, at Boothbay Harbor, Maine. (The solid line is a 5-year movius average.) 





