FISHERY BULLETIN: VOL. 86, NO. 2 



larvae would reach this size in about 5-7 days 

 posthatch. If so, first ring deposition would 

 roughly coincide with hatching. Bluefish hatch in 

 48 hours at 20°C (Deuel et al. 1966), so the day of 

 first ring deposition probably follows the date of 

 spawning by about 2-4 days. 



Spawning Seasons 

 Along the Atlantic Coast 



Published studies of larval bluefish distribu- 

 tions along the Atlantic coast suggest the exis- 

 tence of three temporally and spatially distinct 

 spawning seasons: spring and fall spawning sea- 

 sons in the South Atlantic Bight and a midsum- 

 mer spawning in the Middle Atlantic Bight. In 

 the only synoptic study covering most of the U.S. 

 east coast, Kendall and Walford (1979) described 

 two periods of high larval abundance: One peak 

 occurred in March and April on the outer shelf of 

 the South Atlantic Bight, and the other peak was 

 in July and August midway over the continental 

 shelf of the Middle Atlantic Bight. Subsequently, 

 Powles (1981) and Collins and Stender (1987) also 

 found the highest abundance of bluefish larvae in 

 the South Atlantic Bight (Cape Canaveral to 

 Cape Fear) to be in April and May. Collins and 

 Stender, however, noted the existence of a lesser 

 peak in larval abundance during September- 

 November. This fall spawning season in the 

 South Atlantic Bight was further confirmed by 

 Finucane and Collins (in press) based on the 

 gonad condition of bluefish from Georgia and the 

 Carolinas. In the Middle Atlantic Bight off Vir- 

 ginia, Norcross et al. (1974) found that eggs and 

 larvae of bluefish first appeared in June, peaked 

 in abundance in July, and persisted into August. 

 Similar observations on the timing of the summer 

 spawning season in the Middle Atlantic Bight 

 were presented by Sherman et al. (1984) and 

 Morse et al. (1987). 



Lassiter (1962) provided additional evidence 

 of the existence of relatively discrete spawning 

 seasons in bluefish. He showed that the dis- 

 tribution of back-calculated lengths at age one 

 has a distinctly bimodal pattern among adult 

 fish from North Carolina. Size at age 1 tended 

 to be either about 14 cm or 28 cm. Lassiter 

 showed that the bimodal pattern could not be 

 explained as a difference in growth rate, and 

 suggested that there must be two distinct 

 spawning seasons such that one group of fish had 

 a first growing season about twice as long as the 

 other. 



Spawn Dates of YOY Bluefish 

 from New York 



Back-calculation to the day of first ring deposi- 

 tion for YOY bluefish recruiting to Great South 

 Bay in 1985 and 1986 demonstrated that these 

 fish were spawned primarily in March and April 

 (Figs. 8, 10). Fish that were spawned in July- 

 August were rarely captured by us on Long Island 

 in 1985 or 1986, despite continued sampling into 

 October. 



Recruitment to Jamaica Bay and the Hudson 

 River in July and August 1986 involved YOY 

 bluefish of about the same size as those fi-om 

 Great South Bay. Though the size range of fish 

 fi-om the Hudson was slightly greater than those 

 from Long Island, fish aged from each of the two 

 modes appearing in the July Hudson River sam- 

 ples (Fig. 6) were all spawned during April within 

 about three weeks of each other. The apparent 

 bimodality in July is probably a sampling arti- 

 fact. Hence, Jamaica Bay and Hudson River fish 

 collected in July and August can be attributed to 

 the same spawning season as those fi^om Great 

 South Bay. 



Length-frequency distributions ft"om the Hud- 

 son River in September, however, contained a 

 group of unusually small bluefish, and back- 

 calculation showed that they were spawned pre- 

 dominately in June and July (Fig. 8c). These fish 

 probably resulted fi-om the summer spawning 

 season in the Middle Atlantic Bight. Examina- 

 tion of gonads from adult fish captured during 

 1986 suggested that the running-ripe males and 

 mature females were most abundant during late 

 June and July off Long Island (L. Chiarella and 

 D. O. Conover, unpubl. data). Hence, at least, 

 some summer-spawned YOY bluefish do recruit 

 to the shore zone of the Middle Atlantic Bight. 

 They were, however, much less abundant than 

 spring-spawned YOY bluefish in our 1985 or 1986 

 samples. 



Spawning by bluefish in the spring is known to 

 occur only in the South Atlantic Bight (Kendall 

 and Walford 1979; Collins and Stender 1987). 

 Water temperatures over the shelf north of Cape 

 Hatteras are probably too low for bluefish to 

 spawn in March and April: average shelf water 

 temperatures in the Middle Atlantic Bight range 

 from 5° to 14°C in March and April (Ingham 

 1986). Virtually no eggs and larvae (Morse et al. 

 1987) and comparatively few adult bluefish 

 (Gilmore 1985) are captured in plankton or trawl 

 surveys north of Cape Hatteras in March and 



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