Goldman et al.: Feeding habits of Pagrus pagrus and Batistes capriscus 
323 
Cnidarians 
Isopods 
Stomatopods 
Miscellaneous 
Tunicates 
Echinoderms 
% Bony fishes 
o 
o) Barnacles 
>> 
2^ Bryozoans 
Q. 
Bivalves 
Polychaetes 
Crustaceans, undet. 
Decapods 
Amphipods 
Gastropods 
BSS2SES 
EHS2SSS 
Co 
issss 
I 
%w 
%N 
%F 
0 20 40 60 80 
Percent composition or frequency 
Figure 6 
Percent frequency of occurrence (%F), percent composition by number 
(%N), and percent composition by weight (%W) of prey types present 
in the diet of 82 gray triggerfish (Balistes capriscus) captured in the 
South Atlantic Bight from 2009 through 2011. Prey items consumed 
by fewer than 5% of predators are not included. 
relatively few bivalves. In contrast, large fish had a 
diet dominated by barnacles and bivalves. (Fig. 8D). 
Feeding strategy On the basis of Amundsen graphi- 
cal method, the feeding strategy of the gray trigger- 
fish population is generalized (cluster of points lower 
on the y-axis of the graph) (Fig. 9); several prey items 
are eaten occasionally by most individuals. As with red 
porgy, the predator population has a broad niche width 
(points are all located below the diagonal from the up- 
per left to the bottom right of the graph) (Fig. 9). 
Discussion 
Red porgy 
Across the broad sampling range of this study, red por- 
gy had a very diverse diet. Much of this diversity is 
likely a reflection of localized prey assemblages rather 
than a preference for specific prey items (Bearden and 
Mckenzie^; Manooch, 1977). Manooch (1977) and SC- 
WMED"* reported findings similar to those of our study 
in that they found the red porgy to be a generalized 
predator. However, Manooch (1977) and SCWMRD^ 
identified only 69 and 80 prey taxa, respectively, com- 
pared with the 188 taxa found in our study. In the case 
of the Manooch (1977) study, the difference in number 
of prey taxa may be attributed to the limited geograph- 
ic range of his investigation; samples in that study 
came from only North and South Carolina, whereas 
samples from our study came from an area spanning 
from North Carolina to Florida. 
It is also possible that the abundance of certain 
prey has shifted and, therefore, that red porgy have 
had to diversify their food resources. SCWMRD'* found 
the preferred prey were decapods and fishes and that 
fishes made up the greatest volume of prey. We found 
fishes to be far less important prey (6%W). In contrast 
to Manooch (1977) and our study, SCWMRD^ identified 
more nektonic and fewer benthic prey. In addition, SC- 
WMRD® found very few mollusks in comparison with 
our study. The scientists at SCWMRD suggested that, 
because Manooch (1977) used stomach and intestine of 
red porgy and shelled organisms are slow to be digest- 
ed, bivalves and gastropods would appear to be present 
more frequently than taxa such as small crustaceans 
and polychaetes. This suggestion could be one explana- 
® SCWMRD (South Carolina Wildlife and Marine Resources 
Department). 1981. South Atlantic OCS Area Living Ma- 
rine Resources Study, vol. 1, 297 p. Prepared for Bureau of 
Land Management, Washington, D.C, under contract AA551- 
CT9-27. [Available from Mar. Resour. Library, South Caro- 
lina Dep. Nat. Resour., 217 Fort Johnson Rd., (Charleston, SC 
29412.] 
