Numbers of days to hatching and absorption of yolk sac and per cent cumulative mortality
of chinook salmon reared at city water temperature and various constant temperatures.
Eggs from a single pair from Soos Creek spawned on November 15,
Lot
Number of days to
and
Hatch- Abs. of |Hatch- Feeding
temp.}|
ing*
yolk
ing
°F
sac**
34°
Cumulative mortality in per cent to
34th
46th
week*** week
Remarks
.
100
None hatched; all dead after 156 days
40°
128
225
7
12
14
31
45°
80
145
6
8
8
11
50°
51
97
13
17
22
23
55°
41
81
5
86
86
87
60°
35
73
22
99
100
76
100
62-1/R° 32
65°
Did not feed; weight at 46th week less
than at hatching
High mortality during absorption of
yolk sac
Two survived to feeding;
165th day
(April 28)
last died on
All died before absorption of yolk
sac; last died on 50th day
67°
100
Greatest mortality about time of
hatching; two completed hatching
but died 2 days later (28th day)
All died by 20th day
74°
100
All died within 3 days
City
28
1951.
63
100
126
6
19
27
66
water| 54°-42° 42°-47° 55°-41° 41°-47° 46°-63° 63°-67° Greatest mortality after July 4 when
temp.
64°
water temperature was above 63°F
range
*The day on which 50% of lot was hatched.
**Approximately the day on which all yolk sacs were abosrbed.
***First week in July.