Wood et al.: Diet a of Isurus oxyrinchus in the northwest Atlantic Ocean 
87 
migratory nature of the bluefish, coupled with a variety 
of seasonal fisheries, creates a challenging situation for 
stock management. Bluefish in this region are currently 
managed as a single stock, and although the stock is 
still categorized as overfished, overfishing is not occur- 
ring (Shepherd and Packer, 2006). Decreases in fishing 
pressure have allowed biomass and abundance levels to 
slowly climb since 1997. However, heavily exploited fish 
populations tend to remain in a depressed state for a 
prolonged period following fishing reductions or morato- 
riums (Bakun and Curry, 1999; Hutchings, 2000; Bun- 
dy and Fanning, 2005). One theory offered for the lack 
of recovery in these populations is predation pressure 
(Bax, 1998; Bakun and Curry, 1999). In a depressed 
stock the spawning capability of the prey population is 
held in a depleted state by intense predation (Bakun 
and Curry, 1999). It is evident from this study that 
fisheries managers should consider predation as an 
important factor when managing the recovery of the 
bluefish population in the northwest Atlantic Ocean. 
Acknowledgments 
We thank the numerous fishermen and fishing tourna- 
ment directors who allowed us behind the lines to collect 
samples. We also thank A. J. M. Wood, C. Butler, and 
M. Smith for their aid in the collection, transporta- 
tion, and analysis of stomach contents. Funding for 
this study was provided by the Bluefish-Striped Bass 
Dynamics Research Program at Rutgers University in 
cooperation with the National Marine Fisheries Ser- 
vice (grant NA97FE0363), and the University of Rhode 
Island/National Oceanic and Atmospheric Administra- 
tion/Cooperative Marine Education Research (grant 
NA03NMF4550395). Finally, we thank the many col- 
leagues and anonymous reviewers whose suggestions 
helped to improve this manuscript. 
Literature cited 
Bakun, A., and P. Cury. 
1999. The “school trap”: a mechanism promoting large 
amplitude out-of-phase population oscillations of small 
pelagic fish species. Ecol. Letters 2:349-351. 
Baremore, I. E. 
2007. Feeding ecology of the Atlantic angel shark, Squa- 
tina dumerili , in the northern Gulf of Mexico. M.S. 
thesis, 79 p. Univ. Florida, Gainesville, FL. 
Bax, N. J. 
1998. The significance and prediction of predation in 
marine fisheries. ICES J. Mar. Sci. 55:997-1030. 
Bethea, D. M., J. A. Buckel, and J. K. Carlson. 
2004. Foraging ecology of the early life stages of four 
sympatric shark species. Mar. Ecol. Prog. Ser. 268:245- 
264. 
Bundy, A., and L. P. Fanning. 
2005. Can Atlantic cod ( Gadus morhua) recover? Explor- 
ing trophic explanations for the non-recovery of the cod 
stock on the eastern Scotian Shelf, Canada. Can. J. 
Fish. Aquat. Sci. 62:1474-1489. 
Bush, A., and K. Holland. 
2002. Food limitation in a nursery area: estimates of 
daily ration in juvenile scalloped hammerheads, Sphy- 
rna lewini (Griffen and Smith, 1834) in Kane’ohe Bay, 
Hawai’i. J. Exp. Mar. Biol. Ecol. 278:157-178. 
Carlson, J. K., and G. R. Parsons. 
1999. Seasonal differences in routine oxygen consump- 
tion rates of the bonnethead shark. J. Fish Biol. 
55:876-879. 
Christensen, V. 
1996. Managing fisheries involving predator and prey 
species. Rev. Fish Biol. Fish. 6:417-442. 
Clarke, K. R. 
1993. Non-parametric multivariate analyses of changes 
in community structure. Aust. J. Ecol. 18:117-143. 
Compagno, L. J. V. 
2001. Sharks of the world: an annotated and illustrated 
catalogue of shark species known to date. FAO species 
catalogue for fishery purposes. No. 1, vol. 2. Bullhead, 
mackerel and carpet sharks ( Heterdontiformes, Lamni- 
formes, and Orectolobiformes), 269 p. FAO, Rome. 
Cortes, E., C. A. Brown, and L. R. Beerkircher. 
2007. Relative abundance of pelagic sharks in the western 
North Atlantic Ocean, including the Gulf of Mexico and 
Caribbean Sea. Gulf Caribb. Res. 19: 37-52. 
Cortes, E. 
1997. A critical review of methods of studying fish 
feeding based on analysis of stomach contents: appli- 
cations to elasmobranch fishes. Can. J. Fish. Aquat. 
Sci. 54:726-738. 
Cortes, E., and S. H. Gruber. 
1990. Diet, feeding habits and estimates of daily ration of 
young lemon sharks, Negaprion brevirostris (Poey). Co- 
peia 1990:204-218 
Elliot, J. M., and L. Persson. 
1978. The estimation of daily rates of food consumption 
for fish. J. Anim. Ecol. 47: 977-991. 
Graham, J. B., H. Dewar, N. C. Lai, W. R. Lowell, and S. M. 
Arce. 
1990. Aspects of shark swimming performance deter- 
mined using a large water tunnel. J. Exp. Biol. 151: 
175-192. 
Heithaus, M. R., and L. M. Dill. 
2002. Food availability and tiger shark predation risk 
influence bottlenose dolphin habitat use. Ecology 
83:480-491. 
Hutchings, J. A. 
2000. Collapse and recovery of marine fishes. Nature 
406:882-885. 
Hyslop, E. J. 
1980. Stomach contents analysis - a review of methods 
and their application. J. Fish Biol. 17:411-429. 
Juanes, F., J. A. Hare, and A. G. Miskiewicz. 
1996. Comparing early life history strategies of Poma- 
tomus saltatrix: A global approach. Mar. Freshw. Res. 
47:365-379. 
Kohler, N. E., J. G. Casey, and P. A. Turner. 
1996. Length-length and length-weight relationships for 13 
shark species from the Western North Atlantic. NOAA 
Tech. Memo. NMFS-NE-110, 22 p. 
Korsmeyer, K. E., H. Dewar, N. C. Lai, and J. B. Graham. 
1996. Tuna aerobic swimming performance: Physiological 
and environmental limits based on oxygen supply and 
demand. Comp. Biochem. Physiol. 113:45-56. 
Krebs, C. J. 
1999. Ecological methodology, 2 nd ed., 620 p. Addison 
