770 



Fishery Bulletin 97(4), 1999 



station (Cape May, NJ, to Lewes, DE). Bluefish may 

 attack whelk when the foot is extended out of the shell 

 and may sever that section alone. This would explain 

 the presence of only the foot portion of the animal. 



Summer-spawned bluefish diet was dominated by 

 copepods in the SNE region in 1995. Marks and 

 Conover ( 1993) found that the diet of summer-spawned 

 bluefish collected in surface waters of the New York 

 Bight was dominated by copepods. Summer-spawned 

 bluefish size ranged from 17 to 64 mm TL in their 

 samples and ranged from 20 to 140 mm FL in our 

 samples from the SNE region in 1995. The large pres- 

 ence of copepods in this cohort's diet compared with 



other regions on the shelf in 1995 and with summer- 

 spawned bluefish diets in 1994 is most likely a result 

 of their small size (see "Prey-size analysis" section). 



McBride et al. (1995) found that age-0, spring- 

 spawned bluefish abundance appeared to be regu- 

 lated by density-dependent (compensatory) losses in 

 Narragansett Bay, Rhode Island. One potential den- 

 sity-dependent mechanism is cannibalism. There 

 were very few cases of bluefish cannibalism on the 

 continental shelf; spring-spawned bluefish cannibal- 

 ism of summer-spawned bluefish occurred in the C-D 

 and SOC region in 1995, a year when individuals in 

 the summer-spawned cohort were relatively small in 

 size. However, past diet studies of bluefish have found 

 a higher incidence of cannibalism, particularly off the 

 Carolinas (Lassiter, 1962; Naughton and Saloman, 

 1984). Bluefish abundance is currently low (NEFSCM 

 and cannibalism may be frequent only when bluefish 

 are more abundant or other prey abundances are low. 



We found slight regional differences in the diet of 

 adult bluefish; diets of bluefish in 1994 and 1995 were 

 similar to those found in past studies. In the Georges 

 Bank region in 1994 and 1995, the dominant prey of 

 adult bluefish were butterfish, long-finned squid, 

 boreal squid, round herring, and Atlantic herring. 

 Bay anchovy, butterfish, round herring, and long- 

 finned squid were the dominant prey of adult blue- 

 fish collected from Cape Hatteras, NC, to Montauk 

 Point, NY. Morris (1984) found that long-fmned 

 squid, boreal squid, butterfish, round herring, and 

 bay and striped anchovies dominated the diet of adult 

 bluefish (« =226) captured in NEFSC-NMFS bottom 

 trawls ( 1978-80, spring, summer, autumn combined ) 

 from these same regions. Richards ( 1976) examined 

 the diet of adult bluefish angled near Long Island, 

 NY, in the summer and autumn. The diet of bluefish 

 in this area included bay anchovy, long-finned squid, 

 menhaden iBrevoortia tyrannus), butterfish, and sil- 

 ver hake (n=66, FL range: 490-750 mm). 



There were very few bluefish for our diet analysis 

 from south of Cape Hatteras; however, Naughton and 

 Saloman (1984) collected 729 bluefish from this re- 

 gion using hook and line during 1977-81 and re- 

 ported the diet of bluefish in this area as dominated 

 by Scianidae, Clupeidae, Mugilidae, Labridae, and 

 Atherinidae. Scianids, clupeids, engraulids, sparids, 

 atherinids, and squids were important prey in 

 Lassiter's ( 1962 ) study of over 900 bluefish captured 

 by beach haul seining or hook and line August-Decem- 

 ber 1960 and March, Jun^August 1961. The diet of 

 bluefish (« =42) collected south of Cape Hatteras in the 

 autumn by bottom trawling was dominated by squid, 

 butterfish, and striped anchovy (Morris, 1984). 



There were several commercially important ground- 

 fish species in the diet of adult bluefish on Georges 



