322 
Fishery Bulletin 114(3) 
Crustaceans, unid. 
Cnidarians 
Bryozoans 
Gastropods 
Squid 
Barnacles 
Tunicates 
Protochordates 
Bony fishes 
Polychaetes 
Echinoderms 
Bivalves 
Decapods 
Autumn 
W=14 
■ Summer 
A/=39 
■ Spring 
N=86 
10 
20 
30 
40 
50 
Percent weight 
Percent weight 
60 
Tunicates 
Squid 
Polychaetes 
Q. 
g Gastropods 
^ Echinoderms 
Decapods 
Crustaceans, unid. 
Bony fishes 
Bivalves 
Barnacles 
D 
■ Cluster 2 (large) 
N=39 
■ Cluster 1 (small) 
A/=99 
10 
20 
30 
40 
50 
60 
70 
Percent weight 
Figure 4 
Diet composition by weight of red porgy (Pagrus pagrus) collected in the South Atlantic Bight from 2009 through 2011 
presented by (A) season, (B) depth, (C) latitude, and (D) length. The number (AO of specimens collected in each season, at 
each depth zone, latitude range, or within each length cluster (small=321-420 mm in total length; large=421-520 mm TL) 
is given in the legends, unid^unidentified. 
100 
c 
re 
n 
0 0.2 0.4 0.6 0.8 
Frequency of occurrence (%) 
Figure 5 
Graph of the feeding strategy of red porgy {Pagrus 
pagrus), captured during 2009-2011 in the South At- 
lantic Bight. The graph was developed in this study by 
using the Amundsen graphical method. Each dot repre- 
sents a different prey species. 
Barnacles (35%) and decapods (17%) were the pri- 
mary prey for gray triggerfish captured in the spring 
(Fig. 8A). In the summer, the principal prey of gray 
triggerfish were barnacles (24%) and bivalves (23%), 
and, in the autumn, gray triggerfish consumed primar- 
ily gastropods (40%) and bony fishes (32%). 
Gray triggerfish caught on the inner shelf consumed 
more barnacles, decapods, and polychaetes than did 
their outershelf counterparts, whereas, on the outer- 
shelf, they consumed more gastropods and bivalves 
(Fig. 8B). 
Latitudinal differences in diet were substantial (Fig. 
8C). Fish captured at the southern latitudes (27-29°N) 
preyed upon decapods (59%), and fish captured at the 
northern latitudes (33-34°N) consumed mostly barna- 
cles (57%). Gray triggerfish caught in the central re- 
gion (31-32°N) had a more diverse diet consisting of 
decapods, gastropods, barnacles, and bony fishes. 
Small fish (<400 mm TL) consumed decapods and 
