47 
The trophic dynamics of summer flounder 
( Paralichthys dentotus ) in Chesapeake Bay 
Abstract — Data on the trophic dy- 
namics of fishes are needed for 
management of ecosystems such 
as Chesapeake Bay. Summer floun- 
der (Paralichthys dentatus) are an 
abundant seasonal resident of the bay 
and have the potential to impact food- 
web dynamics. Analyses of diet data 
for late juvenile and adult summer 
flounder collected from 2002-2006 
in Chesapeake Bay were conducted 
to characterize the role of this flat- 
fish in this estuary and to contrib- 
ute to our understanding of summer 
flounder trophic dynamics through- 
out its range. Despite the diversity 
of prey, nearly half of the diet com- 
prised mysid shrimp (Neomysis spp.) 
and bay anchovy ( Anchoa mitchilli). 
Ontogenetic differences in diet and 
an increase in diet diversity with 
increasing fish size were documented. 
Temporal (inter- and intra-annual) 
changes were also detected, as well 
as trends in diet reflecting peaks in 
abundance and diversity of prey. The 
preponderance of fishes in the diet of 
summer flounder indicates that this 
species is an important piscivorous 
predator in Chesapeake Bay. 
Manuscript submitted: 8 May/2007. 
Manuscript accepted: 28 September 2007. 
Fish. Bull. 106:47-57 (2008). 
The views and opinions expressed or 
implied in this article are those of the 
author and do not necessarily reflect 
the position of the National Marine 
Fisheries Service, NOAA. 
Robert J. Latour (contact author) 
James Gartland 
Christopher F. Bonzek 
RaeMarie A. Johnson 
Email address for R. J. Latour: latour@vims.edu 
Department of Fisheries Science 
Virginia Institute of Marine Science 
College of William and Mary 
Route 1208 Greate Road 
Gloucester Point, Virginia 23062 
Summer flounder ( Paralichthys den- 
tatus) are found along the eastern 
seaboard of North America from 
Nova Scotia to Florida, but are most 
abundant between Massachusetts 
and North Carolina (Ginsberg, 1952; 
Leim and Scott, 1966; Gutherz, 1967). 
This species supports both commercial 
and recreational fisheries throughout 
southern New England and the Mid- 
Atlantic Bight. The commercial fishery 
for summer flounder has historically 
accounted for about 60% of the annual 
landings and occurs mainly in the 
offshore waters of the continental 
shelf during late fall and winter. The 
majority of the recreational fishery, 
which on occasions has exceeded the 
commercial harvest, takes place in 
state waters (i.e., estuaries and the 
coastal waters out to 3 nautical miles) 
during summer and early fall. Both 
fisheries contribute millions of dollars 
to economies on local and regional 
scales (Terceiro, 2002). 
The trophic dynamics of summer 
flounder have been fairly well stud- 
ied (Poole, 1964; Smith and Daiber, 
1977; Powell and Schwartz, 1979; 
Roundtree and Able, 1992; Link et 
al., 2002; Staudinger, 2006). However, 
the majority of these investigations 
have documented the diet of summer 
flounder in coastal waters or in more 
northern estuarine environments, 
rather than in the southern estuaries. 
The latter ecosystems support a high 
abundance of summer flounder and 
provide vital summertime habitats for 
this species (Desfosse, 1995). 
The Chesapeake Bay is the larg- 
est estuary in the summer flounder 
range. No known studies have been 
undertaken to document summer 
flounder diet in these waters, and 
thus there has been a gap in our un- 
derstanding of the feeding habits of 
this species within an important area 
of its range. Further, there is growing 
awareness regionally, nationally, and 
internationally of the importance of 
ecosystem-based approaches to fish- 
eries management (EBFM). A neces- 
sary element in support of EBFM is 
nontraditional types of fisheries data, 
including information on the trophic 
dynamics of fishes. 
In this article, we present the diet 
composition of summer flounder col- 
lected in Chesapeake Bay from 2002 
through 2006 to explore ontogenetic, 
interannual, and intra-annual vari- 
ability in diet using canonical corre- 
spondence analysis (CCA). Collective- 
ly, this information provides insight 
into the role of summer flounder in 
the Chesapeake Bay foodweb, and 
contributes to our understanding of 
the trophic dynamics of this species 
throughout its range. 
Materials and methods 
Field collections 
The data presented in this article 
were collected from the Chesapeake 
Bay Multispecies Monitoring and 
Assessment Program (ChesMMAP), 
