764 



BULLETIK OF THE BUREAU OF FISHERIES 



The exact date when this side of the basin is least saline varies from year to 

 year, likewise the minimum value to which the salinity of the surface falls there, our 

 experience up to date suggesting 31.5 to 32.2 per mille as usual at its lowest. In the 

 same way the freshening recorded by Mavor (1923) in the Bay of Fundy early in 

 the summer of 1917 may reflect the transference of the water of low salinity from the 

 Nova Scotian current northward along the eastern side of the gulf, following the 

 route of many of our drift bottles (p. 895). 



Apart from this question, the most interesting aspect of the late summer data 

 for the inner parts of the gulf is the comparative uniformity prevailing at the surface 

 all along the coastal belt from Massachusetts Bay to Grand Manan in 1912 and 1915 

 (31 to 31.9 per mille). It is probable that the isohaline for 32 per mille usually 

 crosses outside the mouth of the Bay of Fundy in July, because Vachon (1918) and 

 Mavor (1923) record surface salinities ranging from 30.36 to 31.48 per mille at 

 various localities in Passamaquoddy Bay and off Grand Manan for that month in 

 1916; 30.61 per mille at Prince station 3, east of Grand Manan, on July 4, 1917; 

 rising to 31.22 per mille there on July 31.^^ 



A considerable body of data has been gathered in the open gulf for the last half 

 of July and for the month of August in the years 1912, 1913, 1914, 1915, and 1922, 

 which, with the determinations for the Bay of Fundy for the summers of 1914, 1917, 

 and 1919 (Craigie, 1916b; Vachon, 1918; and Mavor, 1923) afford a picture of 

 the normal midsummer state of the surface of the gulf, with some indication of the 

 annual fluctuations to which it is subject. 



For salinity, as for temperature, the period, July to August, is the most nearly 

 static part of the year in the open gulf, a statement supported by the following 

 surface readings at pairs of stations at proximate localities but taken several weeks 

 apart. 



» Mavor, 1923. 



' Captain MoFarland. 



*> Surface densities, determined from hydrometer readings in the Bay of Fundy region, also indicate salinities ranging from 

 30.7 per mille to 32.7 per mille (Copeland, 1912; Craigie and Chase, 1918). 



