168 
Fishery Bulletin 115(2) 
74°W 72‘’W 70°W 
43‘'N 
4rN 
39“N 
Figure 1 
Map of the Seekonk River (SR) and Taunton River (TR), in Rhode Island and Massachusetts, respectively, with 
points denoting collection sites for age-0 winter flounder (Pseudopleuronectes americanus) and summer flounder 
(Paralichthys dentatus). Four sites were sampled fortnightly in each river (SR1-SR4; TR1-TR4) from May through 
September 2009-2015, with the exception of SRI, which was not surveyed in 2014, and SR3 and TR3, which were 
not surveyed in 2012-2015. 
vious habitat requirements than pelagic fish (Bailey, 
1994). The transition in habitat use after metamorpho¬ 
sis and subsequent changes in biotic interactions may 
be critical in determining their recruitment success 
and year-class strength. 
The summer flounder {Paralichthys dentatus) is a 
paralichthid flatfish that supports lucrative fisheries 
throughout its geographic range; adults mainly oc¬ 
cupy estuarine and inner continental shelf waters in 
the Mid-Atlantic Bight from Massachusetts to North 
Carolina (Packer et ah, 1999). Summer flounder spawn 
pelagic eggs on the continental shelf during the fall 
and early winter, and peak spawning activity occurs 
in October and November (Packer et ah, 1999). Eggs of 
summer flounder hatch ~3 days after spawning, after 
which planktonic larvae recruit to inshore nurseries 
from October through May and subsequently transition 
to the benthic juvenile life stage. 
The distribution of juvenile summer flounder report¬ 
edly was limited to inshore nurseries between New Jer¬ 
sey and North Carolina (Able and Kaiser^)—a range 
that was delineated at its northern extent by the in¬ 
creased sensitivity of early-stage summer flounder to 
cold water temperatures (<2°C; Malloy and Targett, 
1991). Taylor et al. (2016), however, recently document¬ 
ed a northward shift in the distribution of juvenile 
(age-0) summer flounder and their use of southern New 
England nurseries, including the Narragansett Bay 
and associated tidal rivers. Juvenile summer flounder, 
therefore, have a geographic range that extends far¬ 
ther north than previously recognized. Moreover, the 
northward expansion of juvenile summer flounder is 
attributed to elevated coastal water temperatures in 
^ Able, K. W., and S. C. Kaiser. 1994. Synthesis of summer 
flounder habitat parameters. NOAA Coast. Ocean Program, 
Decis. Anal. Ser. 1, 68 p. NOAA Coastal Ocean Office, Silver 
Spring, MD. 
the northwest Atlantic (Smith et ah, 2010; Taylor et 
ah, 2016), where warmer temperatures affect the dis¬ 
tribution of the adult spawning stock (Nye et ah, 2009) 
and overwintering survival of age-0 summer flounder 
spawned the previous fall (Malloy and Targett, 1991). 
The increased abundance of juvenile summer floun¬ 
der in southern New England nurseries may have im¬ 
portant consequences for resident populations of winter 
flounder. Foremost, the spatial and temporal overlap 
of species could increase interspecific dietary overlap 
and potential competitive interactions in New England 
coastal habitats (e.g., tidal rivers) (Taylor et ah, 2016). 
To date, the diet composition and foraging ecology of 
juvenile winter and summer flounder has not been ex¬ 
amined in this geographic area or habitat-type. There¬ 
fore, the main objective of this study was to evaluate 
the feeding habits and putative biotic interactions 
between age-0 winter and summer flounder collected 
from the Seekonk and Taunton Rivers (in Rhode Island 
and Massachusetts, respectively): 2 tidal rivers that 
are contiguous with Narragansett Bay and serve as im¬ 
portant nursery habitat for both species (Taylor et ah, 
2016). Conventional stomach-content analysis was used 
to explore ontogenetic and spatiotemporal variations in 
intraspecific diet composition and foraging ecology. Di¬ 
rect visual analysis of food habits and complementary 
diet indices were also used to assess the extent of di¬ 
etary overlap of the focal species. 
Materials and methods 
Field sampling 
Age-0 winter flounder and summer flounder were col¬ 
lected from May through September during 2009-2015 
from the Seekonk and Taunton Rivers (Fig. 1). Each 
