Dierking et al.: Diet composition and prey selection of Cephalopholis argus in Hawaii 
467 
Table 2 
Diet composition of peacock hind (Cephalopholis argus) in Hawaii, based on Kona and Oahu samples combined (n total =285, 
n fuiistomachs = 159)’ by number (N), occurrence (i.e., number of stomachs in which a taxon occurred) (O), and mass (M, in g). Dietary 
importance is indicated by percent by number (%N), percent by occurrence ( %0 ) (calculated on the basis of full stomachs), 
percent by mass ( %M ), and percent index of relative importance (%IRI, based on the index of relative importance IR1 = ( %N + 
%M) x%0). %0 and %IRI for fishes and crustaceans are nonadded values (i.e., they correspond to these two food types, not the 
sum of their components). Unidentified fish and crustacean prey were excluded from family-level calculations of % indices. 
Prey taxon 
N 
O 
M 
%N 
%0 
%M 
%IRI 
Fish 
185 
144 
1346.0 
84.5 
90.6 
95.5 
97.7 
Acanthuridae 
14 
13 
137.8 
12.3 
8.2 
11.9 
17.3 
Acanthurus nigrofuscus 
3 
3 
11.2 
Acanthurus nigroris 
2 
2 
89.8 
Zebrasoma flavescens 
2 
2 
18.7 
unidentified Acanthuridae 
7 
6 
18.2 
Apogonidae 
3 
3 
15.3 
2.6 
1.9 
1.3 
0.7 
unidentified Apogonidae 
3 
3 
15.3 
Aulostomidae 
6 
6 
29.4 
5.3 
3.8 
2.5 
4.3 
Aulostomus chinensis 
6 
6 
29.4 
Balistidae 
3 
3 
63.5 
2.6 
1.9 
5.5 
1.3 
Xanthichthys auromarginatus 
1 
1 
53.5 
unidentified Balistidae 
2 
2 
10.0 
Chaetodontidae 
6 
6 
78.6 
5.3 
3.8 
6.8 
4.0 
Chaetodon multicinctus 
1 
1 
16.9 
Forcipiger flavissimus 
3 
3 
21.8 
Hemitaurichthys polylepis 
1 
1 
24.8 
unidentified Chaetodontidae 
1 
1 
15.1 
Cirrhitidae 
4 
4 
37.7 
3.5 
2.5 
3.3 
1.5 
Amblycirrhitus bimacula 
1 
1 
4.6 
unidentified Cirrhitidae 
3 
3 
33.1 
Holocentridae 
16 
16 
52.6 
14.0 
10.1 
4.6 
16.3 
Sargocentron punctatissimum 
1 
1 
4.0 
unidentified Holocentrinae 
15 
15 
48.6 
Kuhliidae 
1 
1 
17.5 
0.9 
0.6 
1.5 
0.1 
Kuhlia spp. 
1 
1 
17.5 
continued 
distributions of the same taxa in the reef environment 
in Kona, by using 2-sample Kolmogorov-Smirnov tests. 
The family Priacanthidae was excluded from the analy- 
sis despite its dietary importance because low counts 
in underwater surveys did not allow for meaningful 
comparison. Minitab 14 software (Minitab Inc., State 
College, PA) was used for all statistical analyses, and 
results were considered significant at P<0.05. 
Results 
Morphometries of C. argus 
Cephalopholis argus SL ranged from 13.2 to 44.0 cm 
(mean: 26.9 cm), and M from 69 g to 2847 g (mean: 721 
g). Morphometric relationships (M-TL, M-SL, SL-TL), 
which have not been reported for this species from large 
sample sizes, are summarized in Table 1. 
Diet composition 
The stomach vacuity rate for the overall sample of 285 
analyzed stomachs was 44.2%, and the mean relative 
stomach content M was 0.74% of C. argus body M (empty 
stomachs included in the calculation). Overall, 219 prey 
items were recovered from 159 full stomachs. Reef fishes 
were the principal diet component (97.7% by %IRI). 
Crustaceans were the only other higher taxonomic group 
in the diet, but were of minor importance (2.3% by %IRI) 
(Table 2). Dietary breadth was wide; a total of 24 prey 
species (20 fish species) in 20 different prey families (16 
fish families) were found in the diet. At the same time, 
the three most important families in the diet made up 
almost 60%, and the eight most important fish families 
close to 90% of the total diet (by %IRI). In declining 
order of importance, these families were the Scaridae, 
Acanthuridae, Holocentridae (exclusively of the subfam- 
ily Holocentrinae, the squirrelfishes), Monacanthidae, 
