123 
National Marine 
Fisheries Service 
NOAA 
Fishery Bulletin 
@ established in 1881 <a 
Spencer F. Baird 
First U.S. Commissioner 
of Fisheries and founder 
of Fishery Bulletin 
Abstract—Predator—prey interactions 
are a vital yet often under-studied reg- 
ulator of marine fish population and 
community structure. However, fish 
prey species often cannot be identi- 
fied by using morphological characters 
because of degradation from diges- 
tion. Consequently, diet is often poorly 
known for piscivorous predators. The 
study described here combined visual 
inspection and molecular diet analysis 
to increase taxonomic resolution for 
prey found in stomachs of red snap- 
per (Lutjanus campechanus) (number 
of stomachs=105) along the Atlantic 
coast of the southeastern United States. 
Overall, the diet of red snapper from 
this region was diverse with 42 inver- 
tebrate and 28 vertebrate taxa iden- 
tified. Broadly, shrimp were the most 
important prey consumed according to 
indices of relative importance (39.95%), 
followed by fish (34.38%) and crab 
(19.04%) species. In total, 19 fish prey 
species were identified by using DNA 
barcoding, compared with 2 species 
identified when visual methods alone 
were used. Results of the use of increased 
taxonomic resolution do not indicate 
significant predation by red snapper 
on other managed fish species in the 
snapper-grouper complex, indicating 
that the rebuilding stock of red snapper 
in the region is not affecting other man- 
aged species through direct predation. 
Manuscript submitted 10 June 2020. 
Manuscript accepted 29 June 2021. 
Fish. Bull. 119:123—134 (2021). 
Online publication date: 29 July 2021. 
doi: 10.7755/FB.119.2-3.3 
The views and opinions expressed or 
implied in this article are those of the 
author (or authors) and do not necessarily 
reflect the position of the National 
Marine Fisheries Service, NOAA. 
Using DNA barcoding to improve taxonomic 
resolution of the diet of red snapper (Lutjanus 
campechanus) along the Atlantic coast of the 
southeastern United States 
Kevin R. Spanik (contact author)" 
Tracey I. Smart' 
Marcel J. M. Reichert’ 
Tanya L. Darden’ 
Email address for contact author: spanikk@dnr.sc.gov 
" South Carolina Department of Natural Resources 
217 Fort Johnson Road 
Charleston, South Carolina 29412 
2 Grice Marine Laboratory 
College of Charleston 
205 Fort Johnson Road 
Charleston, South Carolina 29412 
The importance of predator—prey inter- 
actions on marine fish population and 
community dynamics has been recog- 
nized for decades (Sissenwine, 1984), 
yet it remains challenging to apply 
these interactions in fisheries manage- 
ment. Most of the world’s stock assess- 
ment models focus on only the dynamics 
and fishing pressure of a single-species 
stock, but ecosystem processes signifi- 
cantly affect productivity of fisheries 
(Skern-Mauritzen et al., 2016). Multi- 
species population models and other 
ecosystem-based fisheries management 
approaches that consider ecological 
interactions have recently been imple- 
mented in several countries (Essington 
and Punt, 2011; Kruse et al., 2012). In 
the United States, for example, ecolog- 
ical reference points have been devel- 
oped for fishery management plans 
for species off the Atlantic coast of the 
southeastern United States from North 
Carolina to Florida (“SEDAR, 2020), 
and fishery management plans for spe- 
cies off the coasts of mid-Atlantic states 
from New York to North Carolina now 
aim to conserve vital prey resources for 
managed fish populations (MAFMC, 
2017). Incorporation of ecological inter- 
actions in stock assessments and fishery 
management plans is appropriate for 
species in reef ecosystems off northwest 
Florida because many predators and 
their prey have high site fidelity, and 
high spatial overlap among multiple 
life stages of exploited species has been 
observed (Addis et al.'). 
Diet studies are common and pro- 
vide valuable ecological information 
on resource competition, habitat use, 
trophic structure, energy flow, and sea- 
sonal variability, all important factors 
for ecosystem-based fisheries manage- 
ment. Diet studies also provide esti- 
mates of natural mortality based on 
predation rates, and these estimates 
1 Addis, D. T., W. F. Patterson III, and 
M.A. Dance. 2012. Site fidelity and movement 
of reef fishes tagged at unreported artificial 
reef sites off NW Florida. Southeast Data, 
Assessment, and Review SEDAR31-RD33, 
8 p. [Available from website.] 
