190 
BULLETIN OF THE BUREAU OF FISHERIES 
exact extent of the nonflow period in the latter experiment is not known as the oyster 
began recovery sometime during the night. 
Table 18. — The effect of oil well bleed water on the rate of pumping of water by the gills of the oyster 
[Drop-counting method. Records of two experiments made in Beaufort, 1933] 
Experiment No. 
Date 
Drops per minute, average by 5-minute intervals 
Time 
treat- 
ment 
(min- 
utes) 
Percent. 
bleed 
water 
5 
10 
15 
20 
25 
30 
35 
40 
45 
50 
55 
60 
65 
70 
75 
55 
24 
10 
65 
59 
57 
63 
71 
63 
39 
62 
66 
70 
61 
66 
10 
63 ___ 
4 
10 
130 
130 
123 
125 
121 
119 
101 
119 
104 
109 
115 
107 
5 
03 B 
Dec. 
5 
10 
41 
43 
41 
41 
45 
35 
29 
27 
43 
42 
36 
39 
5 
64 
--do_ 
10 
61 
60 
70 
74 
65 
63 
79 
76 
83 
83 
72 
85 
5 
65C. . 
Dec. 
8 
10 
96 
92 
89 
86 
88 
101 
105 
96 
88 
85 
86 
91 
10 
23 
20 
74 
81 
77 
83 
84 
54 
25 
67 
71 
68 
68 
10 
6 
20 
74 
76 
82 
78 
89 
83 
78 
71 
78 
91 
77 
84 
5 
04 C 
..do. 
20 
99 
95 
96 
90 
88 
81 
57 
69 
79 
85 
92 
112 
10 
8 
20 
90 
95 
92 
91 
88 
89 
86 
87 
98 
94 
94 
91 
10 
53 
Nov. 21 
33.3 
67 
76 
73 
69 
64 
59 
38 
59 
60 
70 
70 
71 
10 
do_ 
33.3 
88 
89 
91 
86 
87 
91 
80 
90 
96 
98 
102 
92 
21 
68 
96 
11 
53 B 
Nov. 
22 
40 
119 
116 
126 
116 
123 
135 
56 
81 
114 
130 
120 
21 
32 
53 
59 
10 
65 
7 
33. 3 
69 
75 
76 
77 
77 
62 
77 
85 
87 
90 
94 
10 
653 __ 
8 
40 
89 
88 
80 
88 
84 
37 
1 
18 
86 
99 
111 
106 
10 
67A 
Dec. 
n 
50 
52 
61 
56 
59 
58 
19 
20 
0 
2 
18 
34 
39 
41 
47 
14 
63A 
Dec. 
12 
60 
52 
69 
77 
81 
76 
38 
2 
0 
0 
9 
26 
31 
37 
37 
38 
10 
68 B 
Dec. 
13 
80 
93 
89 
77 
8 
1 
0 
0 
0 
0 
0 
0 
0 
11 
19 
22 
10 
69 A 
Dec. 
15 
100 
79 
89 
85 
9 
7 
2 
0 
0 
0 
0 
0 
0 
0 
0 
0 
10 
Undiluted bleed water as it comes from the wells, has, as stated above, a specific 
gravity of about 1.1064 (17.5° C.). A 20-percent solution of brine has approximately 
the same specific gravity as the lab- 
oratory sea water during November 
and December. Higher concentra- 
tions of brine undoubtedly owe part 
of their inhibiting action on the gill 
cilia to an increase in density, but 
this effect is probably much less 
pronounced than that caused by its 
chemical composition. It has been 
found, for instance, that in sea 
water, the specific gravity of which 
was increased by the addition of 
salt to 1.0361, the reduction in rate 
of pumping was 2 percent, much less 
than the depression caused by a 20- 
percent solution of brine. Sea water 
having a specific gravity of 1.0422 
(increased by adding NaCl) caused 
a decrease in the rate of flow by 20 
percent, almost equal to that of the 
20-percent solution of brine (spe- 
cific gravity 1 .0258). An inference from these observations is that the inhibitory effect 
is due to the chemical composition of brine rather than to the increased density of 
water. 
The percentage of brine in these experiments is beyond any possibility of occur- 
rence in nature, except under most unusual conditions, and the oyster itself is unable 
to endure so high a salinity for more than a few hours, so that the results of the experi- 
Percent concentrat/on of b/eed water 
Figure 10.— Depression of the rate of pumping of the gills caused by 
various concentrations of “bleed water” (brine). 
