i NOV 1949 
| A NOV 1950 | 
| y DEC 1949 A. DEC 1950 
| 
L JAN 1950 JAN 1951 
FEB 1950 FEB 1951 
MAR 1950 
[ MAR 1951 | 
[Hy > 1 
APR 1950 > APR 195! | 
NUMBER OF FISH 
o 5 8 
iSicy 
MAY 1950 y al 1951 | 
IE JUN 1950 JUN 1951 | 
[ JUL 1950 JUL 1951 
Pm aco 
if AUG 1950 AUG 1951 | 
L al 
L SEP 1950 SEP 195! i] 
mm 
E OCT 1950 OCT 195! | 
Ee 7 Se rier | 
) 10 0 10 20 
RELATIVE OVARY WEIGHT X 103 
Figure 8.--Monthly frequency of relative ovary 
weights for bigeye collected in 
Hawaiian waters. 
° 
& 
MEAN MODAL DIAMETER (MM.) 
il 
NDJFMAMJJASONDJFMAMJJASON 
TIME (MONTHS) 
Figure 9, --Plot of mean modal diameter against 
time for bigeye of Hawaiian waters. 
18 
From observations on residual 
eggs, fractional spawning is strongly 
suspected, The frequency of occurrence 
of randomly selected ovaries with no residual 
eggs, with residual eggs in the early stages 
of reabsorption (characterized by the pres— 
ence of an oil globule, the still tough outer 
membrane, and translucence), or with 
residual eggs in the late stages of reabsorp- 
tion (eggs which were opaque, small, and 
dark) was observed, Of the 121 ovaries 
examined, 60 had no residual eggs, 13 had 
eggs in the early stages of reabsorption, and 
48 had eggs in the late stages of reabsorption. 
The small number of ovaries with eggs in the 
early stages (10.7 percent) indicates that 
residual eggs are not long in this stage; yet 
four ovaries had residual eggs in early stages 
of reabsorption together with developing eggs 
in the late maturing or mature stages. This 
fact indicates a possibility of at least two 
spawnings in close succession, 
FECUNDITY 
In selecting the ovaries for this study, 
the fish were arranged in the following weight 
classes: below 100 lb. (45.4 kg.), 100 lb. to 
129 lb. (45.4 kg. to 58.7 kg.), 130 1b. to 
159 lb. (58.7 kg. to 72.3 kg.), 160 1b. to 
189 lb. (72.3 kg. to 86.0 kg.), 190 1b. to 
219 lb. (86.0 kg. to 99.6 kg.), and over 
220 lb. The ovaries from each class were 
then inspected and only those with maturing 
eggs easily distinguished from the smaller 
eggs were considered, From this group of 
ovaries an attempt was made to select at 
random two ovaries from each size class. 
In the two smallest groups, only one suitable 
ovary for each class was found. 
Pie-sections were cut from transverse 
slices from the middle portion of the ovary 
and weighed immediately to the nearest .001 
gram. The number in the most mature group 
of eggs in the section was then determined by 
actual count and multiplied by the ovary 
weight/sample weight to get an estimate of 
the number of maturing or maturing eggs in 
the ovary. 
Estimates of the number of eggs per 
spawning (table 12) range from 2.9 million 
to 6.3 million. A plot of fecundity against 
fish weight (fig. 10) shows that larger fish 
tend to have more eggs per spawning with 
wide variations between fish of the same size. 
The relation between number of eggs spawned 
and fish weight appears to be curvilinear. 
