8 
PACIFIC SCIENCE, VoL VIII, January, 1954 
centage of Crustacea and annelids and a 
marked decrease in the percentages of all 
other types of food. No foraminifera were 
found. The organisms occurred in the follow- 
ing order of decreasing abundance; Crustacea, 
annelids, insects, algae, spiders, and molluscs, 
with the last two forming very minor items. 
Crustacea (77.6 per cent) were by far the 
most important food of the medium and large 
aholehole, occurring in every one of the 75 
stomachs. The various kinds were distributed 
as indicated in Table 3- 
Crab (Brachyura) megalops were the most 
important item of the crustacean diet; zoea 
were common but of minor bulk; small adults 
were found in only two stomachs. Anomura 
larvae were found in one sample (No. 21). 
The remainder of the crustacean food con- 
sisted mostly of stomatopods (alima larvae) 
and amphipods (mostly gammarids, but also 
hyperiids and caprellids). In contrast to the 
crustacean diet of the small salt-water fish, 
copepods were of relatively minor importance 
to the medium and large salt-water fish. The 
larger fish tended to eat larger organisms. 
Annelids (13.3 per cent) were found in 22 
of the 75 stomachs and consisted of uniden- 
tified motile polychaete worms. They were 
mostly of small size {ca. 2 cm.), but fragments 
of larger worms occurred occasionally. 
Insects (3.3 per cent) were found in 20 of 
the 75 stomachs. They were more common 
in the stomachs of medium-size fish caught 
at the bases of cliffs than in those of the 
large-size fish from the outer edges of the 
reef and the more open water. In the former, 
the insects consisted of midges {Clunio), 
beetles (Carabidae and Scarabaeidae), and a 
wasp. In the latter, they consisted of salt- 
water striders (Halohates), a beetle (Staphylini- 
dae), and an ant. 
Algae (1.9 per cent) were relatively scarce. 
Two spiders (0.1 per cent) were found. Mol- 
luscs (+ per cent) included a small snail and 
postveligers. Other items (3.8 per cent) in- 
cluded chaetognaths, sponge gemmules, bot- 
TABLE 3 
Crustacean Food in the Stomachs of Medium 
AND Large Aholehole from Salt Water, 
Showing Frequency of Occurrence 
AND Percentage by Bulk 
CRUSTACEA 
NUMBER OF 
OCCURRENCES 
PER CENT OF 
TOTAL FOOD 
Crab megalops, zoea, 
and adults 
63 
49.6 
Stomatopod larvae 
20 
6.9 
Amphipods 
36 
6.3 
Shrimp adults and larvae. 
24 
1.8 
Copepods 
15 
1.2 
Mysids 
10 
1.1 
Isopods 
8 
0.8 
Euphausids 
6 
0.1 
Ostracods 
5 
+ 
Nebaliacians 
1 
+ 
Unidentified remains. . . . 
15 
9.8 
tom debris (containing both plant and animal 
remains), eggs, and fish larvae. 
Variation in the Proportion of Stomachs 
Containing Food 
The stomachs of seine and dip-netted small 
aholehole (19 to 30 mm.) taken from both 
fresh and salt water almost invariably con- 
tained food in either the stomach or gut, 
although in some cases it was present in 
traces and was considerably digested. This 
agrees with the general rule pointed out by 
Ricker (1946) and substantiated by Orcutt 
(1950) that, on capture, small fish more fre- 
quently contain food in their stomachs than 
do large fish, a fact which is probably related 
to their greater activity and faster growth rate. 
The stomachs of small fish (30 to 50 mm.) 
taken by hook and line were frequently empty 
or contained only the bait which was used. 
Doubtless this method of fishing selected the 
hungrier individuals. 
In the large fish taken by trap (sample 22) 
the stomachs of all 16 fish contained food. 
In those taken by spear fishing (sample 21 
and others not reported), 12 out of 34, or 35 
per cent, contained food. In those taken by 
poisoning (samples 17 to 20), 100 out of 226, 
or 44 per cent, contained food. In all these 
