448 BULLETIN OF THE BUREAU OF FISHERIES 
SALINITY AND pH 
Because of the predominant deep water in Puget Sound and the relatively small 
streams flowing into the southern portion the variations in salinity are not often great, 
save on the surface. Samples were taken during summer in the exposed dikes, while 
throughout the rest of the year, when low tides occurred at night, samples were taken 
at surface and bottom at the same places. Description of conditions is here limited 
chiefly to Oyster Bay and Mud Bay, in which most of the experimental work was done. 
Since the two bays offer marked hydrographical and biological differences, it is neces- 
sary to go into some detail in describing the relative values of salinity and pH as a 
preliminary to the presentation of biological work. 
On the chart (fig. 4) it will be seen that the two bays are not markedly different 
in size, though Oyster Bay is somewhat longer. In both, most of the oyster beds are 
located at the upper ends where there are relatively level, or gently sloping, bottoms 
exposed at low tide. More fresh water enters Mud Bay through creeks and seepage 
than goes into Oyster Bay, but no large stream enters either. Low salinity probably 
never accounts for any mortality in these bays, though in periods of very heavy rain 
the creeks sometimes wash quantities of silt over some of the beds. 
Table 3. — Comparison of temperature, salinity, and pH, at low tide in 4 dikes in Mud Bay 
(Dike A adjoins shore; others in order to edge of channel) 
Date 
Dike A 
Dike B 
Dike C 
Dike D 
Temper- 
ature 
Salinity 
pH 
Temper- 
ature 
Salinity 
PH 
Temper- 
ature 
Salinity 
pH 
Temper- 
ature 
Salinity 
pH 
1931 
°C 
°C 
°C 
°C 
19.4 
27. 25 
21.7 
27.31 
20.5 
27. 18 
20.5 
27. 12 
20.0 
27. 07 
20.8 
27. 07 
21. 1 
26. 88 
21. 1 
26. 88 
15.7 
25. 90 
16.0 
25. 78 
15.8 
26. 05 
17. 8 
26. 27 
17.9 
25. 91 
18.3 
26.31 
18.3 
26. 30 
16.7 
26. 58 
17.0 
26.31 
17.2 
26. 45 
16.7 
25.28 
13.5 
24. 60 
13.6 
26. 27 
13.5 
25. 75 
13.9 
24. 43 
18.0 
24. 99 
17.8 
25.84 
8.0 
18.3 
24. 58 
7.8 
17.8 
25. 17 
7.8 
July 1 . 
18.3 
25. 95 
18.9 
25. 62 
19.4 
25. 84 
19.7 
25. 95 
17. 2 
26. 65 
20.0 
26. 08 
20.8 
26. 18 
21.4 
26. 18 
July 9__ 
19.4 
26.26 
8.0 
19.7 
26. 02 
7.8 
19.4 
25. 90 
7.8 
19.4 
25. 87 
7.8 
July 13 
16.3 
27. 06 
7.8 
16.7 
26. 94 
7.8 
16.4 
26.82 
7.8 
16.7 
26. 82 
7.8 
July 17 
21. 1 
27. 81 
8.0 
21.7 
27. 75 
8.0 
21.7 
27. 60 
8.0 
23.6 
27. 57 
8.0 
Tuly 20- 
22.2 
27.93 
8. 0 
22.2 
27.48 
8.0 
21.7 
27. 75 
8.0 
22.2 
28. 07 
8.2 
luly 23 
17.2 
27.83 
8.0 
17.2 
27. 83 
8.0 
17.2 
27.83 
8.0 
17.2 
27.83 
8.0 
luly 25 
19.4 
27. 75 
8.0 
19.4 
27. 06 
8.0 
20.0 
27.50 
7.8 
20.0 
27. 48 
7.8 
July 29 
25.8 
28. 42 
8.0 
26. 1 
28. 40 
7.8 
25.8 
28. 27 
7.8 
26.9 
28. 01 
7.8 
26.3 
28. 12 
8.0 
26.4 
27. 79 
8.0 
25.5 
27. 75 
26. 4 
27. 69 
8.0 
Aug. 7 
14.7 
28. 13 
7.8 
15.0 
27. 95 
7.8 
15.3 
27.98 
7.8 
15.3 
27. 98 
7.8 
Aug. 12 
21.4 
28.65 
8.0 
21.1 
28.51 
8.0 
20.5 
28. 36 
8.0 
21. 1 
28. 10 
7.8 
Aug. 21 
15.0 
28. 59 
7.8 
15.0 
28.41 
7.8 
15.0 
28. 60 
7.8 
15.0 
28. 30 
7.8 
17. 5 
29. 72 
17.5 
28.51 
17.5 
28.31 
17.5 
28. 19 
Aug. 26 
18.9 
28.82 
18.9 
28.31 
7.8 
18.6 
28.15 
7.8 
19.3 
28.24 
7.8 
Sept. 5 
17.8 
25.52 
7.4 
18.5 
27. 84 
7.4 
18.3 
27.63 
7.4 
18.6 
26.58 
7.4 
15. 5 
28. 65 
15.5 
28.35 
7.8 
15.5 
28. 06 
15.5 
27. 92 
16.7 
28. 51 
16. 1 
28. 19 
15.8 
28. 26 
15.0 
27. 78 
Oct. 8 
11.7 
28.44 
7.8 
n.i 
27.88 
7.6 
10.5 
27.64 
7.6 
ii. i 
27. 65 
7.7 
In order to indicate the general results of tests on oyster grounds throughout the 
year, and the close comparison in salinity and pH of the water on various grounds, 
the values are given in table 2 for samples taken in two dikes in Oyster Bay, 1932. Dur- 
ing the summer season samples were taken at low tide when the dikes were exposed 
and the water quite warm, while at other times of year bottom samples were taken. 
The day-to-day variation in salinity is not great, and although dike 5 is well up the 
bay and dike S about 2 miles away (see chart, fig. 4) there is little difference to be 
noted. 
