Soon after fertilization eggs of the Crucian carp,
Cyprinus carpio, were put in 20 vials with water. Two of them were then placed in each of 10 compartments (Nos. 1-10) of a S
ENÔ-T
AUTI's serial incubator. They ran at temperatures differing from each other by nearly two degrees, No. 1 at the lowest (11.0°C.) and No. 10 at the highest (30.2°C.). With a view to determine the effects of temperature variations on the developing eggs one of the two vials in each compart-ment was interchanged with the corresponding one in another but the other vial in respective section was kept
in situ as control. The interchange was made in 5 pairs, viz., No. 1 with No. 10, No. 2 with No. 9, No. 3 with No. 8, No. 4 with No. 7, and No. 5 with No. 6. The results, obtaind may be summarized as follows: -
1) Water temperature for normal development of the eggs ranges from 15° to 30°C., the optimum for it being at about 20°C.
2) The relation between the temperature (θ) and time in days (
T) required for the eggs may be expressed, as given by H
IGURASHI and T
AUTI, by the formula
Teaθ=constant, in which a=0.09. The temperature coefficient for the embryonic development of the carp was found to be
Q10=2.5.
3) Within the range of mean deviations 0.9-9.4°C. in the series of temperatures 11.0-30.2°C, the larger the temperature deviation the less the hatch-rate of the fry and the less the time required for hatching.
4) T
AUTI's formulae concerning the relation between the mean deviations of the water temperatur (
M) and timein days (
TM) and that between the former and the percentage of the hatched fry ((
N/
N0)
M) viz.,
T0/
TM-1=a
2/2M
2, and (
N/
N0)
M=(
N/
N0)
0e-cM2 where
T0 and (
N/
N0)
0 are the time and the percentage when
M=0 respectively, hold true for my material with the values of the constants
c=0.0142,
a=0.081,
Q10=2.3.
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