374 
PACIFIC SCIENCE, Vol. XI, October, 1957 
(wet) ovaries, weighing a wedge-shaped sec- 
tion from one of the ovaries, and counting 
the number of eggs in the most mature group 
in this sample. The total number of mature 
eggs in both ovaries was then calculated by 
simple proportion. 
This estimate of 6.1 million eggs per spawn- 
ing is comparable in order of magnitude to 
the amount of spawn released by some other 
related species. Yuen (1955: 18) computed 
the number of eggs extruded in one spawning 
of a bigeye tuna, Parathunnus sibi (Temminck 
and Schlegel), in the Pacific to be 2.9 to 6.3 
million; June (1953: 63) estimated the number 
of eggs per spawning of a yellowfin sampled 
in Hawaii to be 2 to 8 million. Both authors 
found that the number of eggs spawned in- 
creased, in general, with increase in size of 
fish. This probably holds true for the wahoo. 
FOOD HABITS 
Of the 235 stomachs examined, 115 (48.5 
perjcent) were empty. This relatively large 
number of empty stomachs may be due to 
regurgitation on capture. The wahoo strug- 
gles violently on the trolling line and may 
regurgitate food while being landed and killed. 
As some of the stomach contents were prob- 
ably incomplete, an elaborate analysis of the 
food based on percentage by volume was not 
undertaken. Rather the analysis was confined 
to frequency of occurrence of the various 
food items. 
Fish remains have a high frequency of oc- 
currence among the food items (Table 2), 
and perhaps beyond their true significance 
since fish bones are slow to digest and hence 
persist longer in the stomachs than readily 
digested items. In both time periods (March, 
and November-December) mackerel scad, 
squid, and skipjack appear to be of impor- 
tance in the food, with mackerel scad being 
the major item. 
A much greater variety of food than is in- 
dicated by Table 2 is probably consumed by 
the wahoo. Very small items could have been 
overlooked. On infrequent occasions speci- 
mens were on deck for several hours prior to 
the examination of the stomachs, and the 
TABLE 2 
Stomach contents of 235 troll-caught wahoo captured during March, 
and November-December, 1955 
FOOD ITEMS 
FREQUENCY OF 
OCCURRENCE 
PER CENT FREQUENCY 
OF OCCURRENCE 
March 
November- 
December 
March 
November- 
December 
Items identifiable 
Squid ( Loligo sp.) 
6 
3 
18.2 
13.0 
Skipjack ( Katsuivonus pelamis ) 
4 
6 
12.1 
26.1 
Pomfret (Bramidae) 
1 
1 
3.0 
4.4 
Puffer (Tetraodontidae) 
2 
2 
6.1 
8.7 
Mackerel scad ( Decapterus [ psinnulatus ]) 
19 
9 
57.5 
39.1 
Flying fish ( Cypselurus sp.) 
1 
3.0 
Lantern fish (Myctophidae) 
1 
4.4 
Sunfish (Ranzania truncata ) 
1 
4.4 
Total 
33 
23 
99.9 
100.1 
Entire sample 
Empty stomachs 
34 
81 
39.1 
54.7 
Fish remains not identifiable 
20 
44 
22.9 
29.7 
Food remains identifiable 
33 
23 
37.9 
15.5 
Total 
87 
148 
99.9 
99.9 
