456 
BULLETIN OF THE BUREAU OF FISHERIES 
while at the upper end of the latter more fresh water flows in. As a result, in Mud Bay 
the oysters are subjected to frequent changes in salinity at different stages of the tide 
while in Oyster Bay the changes are 
relatively slight. These differences 
are considered below in the com- 
parison of the spawning and setting 
activities of oysters in the two 
places. It may be noted on the 
chart (fig. 4) that the mouths of Oys- 
ter and Oakland Bays are close to- 
gether but that the latter bay is 
entered through a long, narrow 
channel. It is of interest to com- 
pare the salinity in the dikes of the 
two bays at low tide. In table 11 
salinities are given for dike 5 in 
Oyster Bay, a typical dike in 
Skookum Inlet, and one in Oakland 
Bay. Larger streams flow into 
Oakland Bay and elimination is less 
readily accomplished, so that even 
during dry summer weather the 
salinity is lower than in Oyster Bay. 
Water entering the latter at flood 
tide is of lower salinity than that 
which goes into Mud Bay, probably 
because of outflow from Oakland 
Bay and neighboring waters. Com- 
plete exchange of water with tides 
is accomplished much more slowly 
than in Mud Bay, the water in which is therefore higher in salinity as well as colder 
and not as favorable for the propagation of oysters. 
Figure 14. — Vertical distribution of salinity, temperature, and pH off 
Corters Point (Oyster Bay) summer (S) and winter (W). Compare 
Mud Bay, figure 13. 
Table 11. — Comparison of salinity of water in dikes at low tide in Oyster Bay, Little Skookum, and 
Oakland Bay in summer 
Date 
Oyster 
Bay 
Little 
Skookum 
Oakland 
Bay 
1933 
Salinity 
Salinity 
Salinity 
May 22 
27.17 
25. 68 
23. 30 
27. 05 
24.03 
May 26 
26.91 
23. 86 
23.69 
May 29 
26. 88 
25.09 
23.66 
May 31 
27. 35 
24. 22 
27. 17 
24. 71 
June 5 
27. 50 
25. 91 
24. 09 
June 7 
27. 59 
24. 23 
June 9 
27. 27 
25.47 
24. 37 
June 12 
26. 77 
25. 61 
25. 39 
27. 54 
25. 76 
June 16 
27. 21 
26. 10 
24.83 
June 19 
27. 92 
25. 97 
25. 10 
Date 
Oyster 
Bay 
Little 
Skookum 
Oakland 
Bay 
1933 — Continued 
June 21 
Salinity 
27. 49 
Salinity 
Salinity 
25. 43 
June 23 
27. 43 
27.01 
25. 10 
June 26 
27. 16 
26. 06 
25. 52 
June 28. 
28. 07 
24. 65 
June 30 
27. 92 
24. 94 
July 3 
27. 69 
25. 25 
24. 90 
July 5 
27. 77 
25.46 
July 7 
27. 11 
25. 99 
July 14 ... 
27. 83 
26. 97 
26. 15 
July 17 
28.01 
26. 68 
26.05 
July 19 
28. 12 
25.91 
July 21 
28. 21 
27.16 
24. 25 
July 24 
28. 13 
28. 22 
26.44 
SPAWNING 
The native oyster of the Pacific coast, Ostrea lurida, is biologically similar to the 
European oyster, 0. edulis, in that it is hermaphroditic and viviparous. In his 
original studies of the native oyster, Stafford (1913, 1914) described the hermaphro- 
ditism, pointing out that in the gonad, or ovotestis, eggs and sperms may be seen close 
together. Until the recent work of Coe (1931a, 1931b, 1932a) no further exact infor- 
