Latour et al.: The trophic dynamics of Paralichthys dentatus in Chesapeake Bay 
53 
Small (<225 mm) 
n c = 88 
n,= 128 
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<>v s 
Large-med. (375 mm-574mm) 
n c = 312 
n, = 438 
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Figure 6 
Diet composition (percent weight) of summer flounder (Paralichthys dentatus) collected from the 
mainstem of Chesapeake Bay, presented by (A) size-category, (B) month, and (C) year. The number 
of clusters collected in each subcategory is given by n c , and n t represents the total number of speci- 
mens. Error bars represent standard error of the percent weight values of each of the prey types 
encountered in the summer flounder diet, which were calculated from cluster sampling variance 
estimates. 
flounder. Interannual variations in the diet of summer 
flounder generally followed fluctuations in the indices 
of relative abundance for several prey species routinely 
monitored by the Virginia Institute of Marine Science 
(VIMS) Juvenile Finfish and Blue Crab Trawl Survey. 
There was a weak visual correspondence between the 
trends in relative abundances of bay anchovy and YOY 
weakfish and their contributions to summer flounder 
diet throughout the study period. However, the diet 
of summer flounder more strongly mirrored trends in 
relative abundance of YOY spot. 
In general, it is difficult to compare studies of diet 
composition of the same species because it is often the 
case that survey design (including gear types), indices 
reported (e.g., percent weight, %W vs. percent number, 
%N), and the methods used to calculate these indices 
(e.g., simple random vs. cluster sampling) vary among 
studies. Although these differences prohibit direct 
comparisons among investigations, it is still possible 
to draw some informative qualitative conclusions. For 
example, Smith and Daiber (1977), using the percent 
frequency of occurrence (%F) index, reported that the 
diet of summer flounder in Delaware Bay was domi- 
nated by invertebrates; yet their results also indicated 
that fishes composed an important part of their diet 
in the estuary. Poole (1964) reported that sand shrimp 
were the main prey by weight of summer flounder in 
Great South Bay, NY; however, fishes were also abun- 
