544 



BULLETIN" OF THE BUREAU OF FISHEEIES 



the observations were made so s oon after the coldest time of year that the temper- 

 ature had not risen more than fractionally, it seems safe to say that the water did 

 not cool below 1.5° to 2° in the northern half of the bay during the winters of 1921 

 or 1925, except right along the land, where it is most subject to winter chilling, 

 instead of close to 0°, as in 1920. 



Fig. 20.— Depth below the surface of the isothermobath for 4°, February-March, 1920 



A similar relationship obtained between the years 1920 and 1921 at the mouth 

 of the Bay off Gloucester (fig. 21), the following readings taken there in the first 

 week of March pointing to a minimum of 1.5° to 2° for the winter of 1920 and 

 about 3° for 1921. 



