730 
BULLETIN OF THE BUREAU OF FISHERIES 
on the deeper strata as water moves over the bottom from greater depths farther out 
at sea. Observations taken off the Isles of Shoals on April 16 and 22, 1913, illustrate 
this by an increase in the salinity of the whole column. 
Any April profile running out from the northern or western shore of the gulf 
will show the effect of the vernal runoff of land water by a band of low surface 
salinity at the inshore end, broader or narrower and with actual values higher or lower, 
according to the exact locality. Profiles from Massachusetts Bay (fig. 110) show it 
as a wedge less saline than 32 per mille based against the western slope of the gulf. 
Profiles normal to the coast anywhere between Portland and Penobscot Bay, for 
this same month, would have cut across still lower salinities next the land. Its 
direct result is the development of a stratum less saline than 32.5 per mille, 50 to 
60 meters thick, by April, blanketing the surface from the western shores right 
.4 .5 .6 .7 .8 .9 32 .1 .2 .3 .4 .5 .6 .7 .8 
Fig. 107. — Vertical distribution of salinity a few miles off Mount Desert Island in various months. A, 
March 3, 1920 (station 20056); B, April 12,1920 (station 20099); C, July 19, 1915 (station 10302); D, 
August 18, 1915 (station 10305); E, October 9, 1915 (station 10328) 
out to the central part of the basin, where only a superficial layer, 10 meters or so 
thick, has so low a salinity in March. 
Observations taken in the eastern side of the gulf at any time during the few 
weeks when the Nova Scotian current is bringing a large volume of comparatively 
fresh water past Cape Sable would show a similiar wedge of low salinity, basing on 
German Bank and extending out over the eastern side of the basin. This state is 
illustrated on the profile for 1919 (fig. 103). In 1920, however, neither of our 
spring cruises coincided with this event, so that the isohalines projected in east-west 
profile inclose homogeneous water over German Bank (fig. 110), just as they do at 
other times of year. 
Along the western coast of Nova Scotia (figs. 109 and 110) the tides stir the 
water so thoroughly that vernal alteration at first proceeds at a nearly uniform rate, 
