Overton et al.: Interactions between Morone saxatilis and their prey during winter off the North Carolin coast 
181 
itlUXL 
J k 
0.25 0.30 0.35 
Prey-predator ratio (PPR) 
0.40 0.45 0.50 
Figure 5 
Prey-to-predator ratio (PPR) frequency distributions determined from the 
diet of striped bass ( Morone saxatilis ) collected in trawl and recreational 
catch samples during winter off the coasts of Virginia and North Carolina 
during 1994-2007. 
Coastwide population-level con- 
sumption of Atlantic menhaden by 
striped bass in the Atlantic Ocean 
increased from 50xl0 3 t in 1982 to 
over 250xl0 3 t in 2000 (Overton, 
2003). Striped bass are capable of 
exerting considerable pressure on 
prey populations through predation 
(Hartman, 2003; Grout, 2006). With 
concerns over Atlantic menhaden re- 
cruitment, it is essential to quantify 
its role as a prey fish and its major 
sources of mortality. 
Our diet data were collected by 
using two different methods during 
two separate time periods; therefore 
we were unable to test the effects of 
collection methods on the diet com- 
position. Nevertheless, we feel that 
the two collection methods comple- 
ment each other. For example, the 
trawl samples (1994-2003) show 
an increasing trend in the amount 
of Atlantic menhaden consumed; 
these data are supported by the 
recreational catch data. Simultane- 
ously, the trawl data show a decline 
in the consumption of bay anchovy 
diet, which is also supported by the 
recreational catch data. These re- 
sults indicate that the recreational catch data provide 
a reasonable representation of the diet of striped bass 
during the winter off the coasts of North Carolina and 
Virginia. 
To further understand the predator-prey interac- 
tions of striped bass, we suggest a continued low-fre- 
quency monitoring of predator diets along the Atlantic 
coast. Low-frequency monitoring approaches have been 
used to estimate the consumption of commercially 
important fish by predatory fish in the western North 
Atlantic and can provide important insights regard- 
ing the importance of prey types (Overholtz et ah, 
2000). These data can be used to calibrate different 
predator-prey, bioenergetic, and multispecies models 
for different management systems. This information 
could provide data that would add significantly to 
knowledge of trophic interactions of striped bass and 
other predators. 
This analysis of the foraging behavior of large migra- 
tory striped bass during their winter residency in the 
Atlantic Ocean contributes to the increasing literature 
on the foraging dynamics of predatory fishes. Whether 
the patterns observed during our study period were 
the result of prey dynamics or predator function is 
unclear. However, striped bass feed on a large number 
of prey during winter and are also capable of feeding 
on a wide range of prey sizes. This work outlines the 
importance of clupeoid fishes to striped bass winter 
production and also shows that predation may be ex- 
erting prey pressure on Atlantic menhaden stocks. 
Acknowledgments 
We thank W. Laney (United States Fish and Wildlife 
Service) and H. King (Maryland Department of Natural 
Resources) for financial support. We especially thank J. 
Price of the Chesapeake Bay Ecological Foundation for 
continued support both financially and in the field and 
K. Riley for providing comments that greatly improved 
this manuscript. We also thank personnel at Oregon 
Inlet Fishing Center, particularly M. Swain, for use 
of their facilities. We acknowledge J. Clermont, M. 
Butler, C. Lee, and N. Jones for assisting in the field 
collections. 
Literature cited 
Bax, N. J. 
1998. The significance and prediction of predation in 
marine fisheries. ICES J. Mar. Sci. 55:997-1030. 
Boreman, J., and R. R. Lewis. 
1997. Atlantic coastal migration of striped bass. Am. 
Fish. Soc. Syrnp. 1:331-339. 
Field, J. D. 
1997. Atlantic striped bass management: Where did 
we go right? Fisheries 22:69. 
Grout, D. E. 
2006. Interactions between striped bass ( Morone saxatilis ) 
rebuilding programmes and the conservation of Atlantic 
salmon ( Salmo salar ) and other anadromous fish species 
in the USA. ICES J. Mar. Sci. 63:1346-1352. 
