Butler et al.: Feeding ecology of Thunnus thynnus in North Carolina 
61 
Table 2 
Stomach contents of giant (>205.7 cm curve fork length [CFL]) Atlantic bluefin tuna (Thunnus thynnus) caught off Cape Lookout, 
North Carolina, during Dec. 2003-Jan. 2004, Dec. 2004-Jan. 2005, and Dec. 2005-Jan. 2006. Diet is presented as percent fre- 
quency of occurrence (%0) and percent prey weight (%W). 
Prey item 
Dec. 2003- 
Jan. 2004 
Dec. 2004- 
Jan. 2005 
Dec. 2005- 
Jan. 2006 
Poolec 
years 
%0 
%W 
%0 
%W 
%0 
%W 
%o 
%W 
Chordata 
Arnmodytes sp. 
1.00 
0.01 
0.79 
<0.01 
Anchoa hepsetus 
1.00 
0.01 
0.73 
<0.01 
0.79 
<0.01 
Archosargus sp. 
1.00 
0.11 
2.19 
0.11 
1.59 
0.11 
Brevoortia tyrannus 
60.00 
91.39 
84.00 
98.96 
83.21 
92.97 
82.54 
94.71 
Chilomycterus sp. 
1.46 
0.07 
0.79 
0.04 
Cynoscion regalis 
1.46 
0.46 
0.79 
0.31 
Diapterus auratus 
6.67 
1.78 
0.40 
0.04 
Engraulidae 
6.67 
0.16 
0.40 
<0.01 
Lagodon rhomboides 
0.73 
0.05 
0.40 
0.03 
Micropogonias sp. 
0.73 
0.04 
0.40 
0.03 
Mustelus canis 
0.73 
0.16 
0.40 
0.11 
Orthopristis chrysoptera 
2.19 
0.04 
1.19 
0.03 
Pomatomus saltatrix 
0.73 
0.01 
0.40 
0.01 
Sphyraena borealis 
0.73 
0.04 
0.40 
0.02 
Strongylura marina 
1.00 
0.01 
12.41 
4.61 
7.14 
3.16 
Syngnathus louisianae 
1.00 
0.01 
0.40 
<0.01 
Syngnathus sp. 
0.73 
<0.01 
0.40 
<0.01 
Triglidae 
6.67 
0.52 
0.40 
0.01 
Unidentified fish remains 
40.00 
0.74 
14.00 
0.09 
15.33 
0.34 
15.87 
0.27 
Crustacea 
Callinectes sapidus 
6.67 
0.17 
0.40 
<0.01 
Ovalipes sp. 
13.33 
0.37 
3.00 
0.16 
3.65 
0.04 
3.97 
0.08 
Portunidae 
6.67 
0.10 
6.00 
0.17 
0.73 
<0.01 
3.17 
0.05 
Portunus gibbesii 
13.33 
4.28 
8.00 
0.15 
7.30 
0.15 
9.13 
0.24 
Portunus spinimanus 
6.67 
0.33 
4.00 
0.09 
2.92 
0.05 
3.57 
0.07 
Portunus spp. 
1.00 
0.02 
7.30 
0.07 
4.37 
0.05 
Unidentified crab 
13.33 
0.12 
6.00 
0.08 
3.65 
0.02 
5.16 
0.04 
Mollusca 
Loligo pealeii 
2.00 
0.07 
2.19 
0.48 
1.98 
0.35 
Unidentified squid 
8.03 
0.30 
4.37 
0.20 
Unidentified clam 
1.00 
0.06 
0.40 
0.02 
Protista 
Unidentified algae 
6.67 
0.03 
1.00 
<0.01 
0.73 
0.01 
1.19 
0.01 
Total prey biomass (kg) 
7.54 
106.23 
245.43 
359.20 
Total stomachs sampled 
28 
139 
157 
324 
Stomachs with prey (%) 
15 (53.6) 
100(71.9) 
137(87.3) 
252(77.8) 
Empty stomachs (%) 
13 (46.4) 
39 (28.1) 
20(12.7) 
72(22.2) 
Mean length of bluefin tuna (cm 
217.56 
223.14 
225.92 
224.01 
Standard Error 
1.89 
0.93 
1.12 
0.71 
Mean weight of bluefin tuna (kg 
155.12 
172.09 
179.17 
174.66 
Standard Error 
5.25 
2.70 
3.37 
2.08 
Population-level consumption 
Using bluefin tuna abundance data from 2005, we esti- 
mated that Cpop ranged from 189 to 13,385 metric tons 
(t) (mean=3,021 t; Fig. 4A). For a completely restored 
bluefin tuna population, estimates ranged from 986 to 
42,858 t (mean=10,020 t; Fig. 4B). At 2005 population 
levels, the maximum estimate of C Pop was below the 
majority of estimates of annual predatory demand by 
other predators of Atlantic menhaden; other predators 
were bluefish, striped bass, and weakfish (Fig. 5). How- 
ever, the maximum estimate of C Pop by a fully restored 
