NYMAN and CONOVER: YOUNG-OF-THE-YEAR BLUEFISH 



April. Moreover, the time of arrival of YOY blue- 

 fish on Long Island actually precedes the summer 

 spawning season in the Middle Atlantic Bight. 

 We therefore conclude that YOY bluefish recruit- 

 ing to the Middle Atlantic Bight in late spring 

 come from spawnings in the South Atlantic 

 Bight. 



Larval Transport 



The physical mechanisms that account for the 

 transport of bluefish larvae fi"om the South At- 

 lantic Bight to New York are not clear. Spawning 

 in the South Atlantic Bight occurs primarily over 

 the outer half of the continental shelf (Powles 

 1981; Collins and Stender 1987), and some larvae 

 may be entrained by the Gulf Stream and carried 

 northward into the slope waters of the Middle 

 Atlantic Bight (Kendall and Walford 1979). 

 Neuston net collections in April have shown that 

 bluefish larvae are periodically abundant on both 

 sides of the Gulf Stream-shelf water interface off 

 Cape Hatteras (Kendall and Walford 1979). 

 Collins and Stender (1987) found a negative cor- 

 relation between larval size and latitude in the 

 South Atlantic, but their sampling may not have 

 extended far enough north (i.e., they did not sam- 

 ple above Cape Fear). 



If the Gulf Stream is responsible for the north- 

 ward transport, a mechanism by which larvae 

 avoid being advected too far offshore would ap- 

 pear to be necessary. According to our results, the 

 interval between spawning and recruitment to 

 Long Island is about 45-60 days, whereas the 

 surface flow of the Gulf Stream at lat. 36°N is 

 about 104 km/day (Iselin 1936). Hence, larvae re- 

 maining in the Gulf Stream for an extended pe- 

 riod would be transported far off the shelf. Reten- 

 tion near the shelf could be achieved by entering 

 the slope waters at an appropriate time. 



The abrupt appearance of YOY bluefish in the 

 shore zone suggests that the onshore migration is 

 a temporally distinct event, perhaps triggered by 

 vernal warming of the shelf. Because the circula- 

 tion of the slope and shelf waters of the Middle 

 Atlantic Bight is toward the southwest (Sherman 

 et al. 1984), the cross-shelf migration must to 

 some extent involve active swimming. 



Very few summer-spawned YOY bluefish were 

 captured in our study. This may not be surpris- 

 ing, however, because the prevailing currents 

 over the midshelf off Long Island would carry lar- 

 vae to the southwest. If so, summer-spawned fish 

 would be found along the coast fi"om approxi- 



mately New Jersey to Cape Hatteras. We caution, 

 however, against any general conclusion concern- 

 ing the lack of summer-spawned fish in New 

 York. There could, for example, be substantial 

 year-to-year variation in the recruitment level of 

 spring- and summer-spawned fish along any par- 

 ticular segment of the U.S. coast. These issues are 

 now being examined by extending our sampling 

 to southern latitudes. 



ACKNOWLEDGMENTS 



We thank Robert Cerrato, Robert K. Cowen, 

 and Peter Woodhead for reviewing the manu- 

 script and Stephen Heins, Melanie Meade and 

 Louis Chiarella for assistance in the field. Byron 

 Young and Kim McKown of the NYDEC gra- 

 ciously provided samples from the Hudson River 

 and Jamaica Bay. An earlier version of this paper 

 was submitted by R.M.N, to the Graduate School 

 of the State University of New York at Stony 

 Brook in partial fulfillment of the requirements 

 for an M.S. degree in Marine Environmental Sci- 

 ences. Initial funding was provided by grants 

 from the Sport Fishery Research Foundation 

 (D.O.C./R.M.N.) and the Montauk Marine Basin. 

 Later funding was provided by grants to D.O.C. 

 fi-om the NYDEC through the Dingell-Johnson 

 Federal Aid in Sport Fish Restoration Act and 

 by the New York Sea Grant Institute through 

 the NOAA Office of Sea Grant, U.S. Department 

 of Commerce, under Grant No. NA86AA-D- 

 SG045. 



LITERATURE CITED 



BiGELOW, H. B., AhfD W. C. SCHROEDER. 



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