THE RELATION BETWEEN SPAWNING SEASON AND 



THE RECRUITMENT OF YOUNG-OF-THE-YEAR BLUEFISH, 



POMATOMUS SALTATRIX, TO NEW YORK^ 



Robert M. Nyman^ and David O Conover^ 



ABSTRACT 



The association between oceanic spawning season and the recruitment of young-of-the-year (YOY) 

 bluefish, Pomatomus saltatrix, to the inshore waters of New York was studied by estimating the 

 spawn dates of recruited fish collected in the shore zone from the number of growth increments in 

 their otoliths. Field collections on the south shore of Long Island showed that recruitment of 3-6 cm 

 fork length fish occurred as a distinct pulse during the last week of May in 1985 and the second week 

 of June in 1986. Length-frequency distributions were generally unimodal and most fish collected later 

 could be attributed to this one recruitment episode. The frequency of otolith ring deposition in YOY 

 bluefish was determined by marking the otoliths of field-caged fish with an injection of tetracycline, 

 and then periodically subsampling these over the ensuing 61-day period. Regression analysis indi- 

 cated a 1:1 relation between the number of days since marking and the number of rings beyond the 

 mark. Back-calculation to the time of first ring deposition revealed that field-collected YOY bluefish 

 from Long Island were spawned primarily in the March-April spawning season reported to occur 

 south of Cape Hatteras. Relatively few fish were collected from the summer spawning season that 

 reportedly occurs in the Middle Atlantic Bight. Almost all of these summer-spawned fish were 

 collected from the Hudson River. 



The bluefish, Pomatomus saltatrix, supports a 

 major recreational fishery along the Atlantic 

 coast of the United States. In 1985, more bluefish 

 by weight were caught than any other marine 

 fish, accounting for over 24% of the total marine 

 recreational catch (U.S. Department of Com- 

 merce 1986). Despite the importance of bluefish 

 to the recreational fishery, very little is known of 

 its early life history. 



Bluefish are found over different portions of the 

 continental shelf from Florida to Nova Scotia at 

 various times of the year (Bigelow and Schroeder 

 1953; Wilk 1977; Gilmore 1985). Based on de- 

 scriptions of the temporal and spatial abundance 

 of larvae, Kendall and Walford (1979) suggested 

 that there are primarily two distinct spawning 

 periods and regions: a spring spawning in the 

 South Atlantic Bight at the edge of the Florida 

 Current (see also Collins and Stender 1987), and 

 a summer spawning in the Middle Atlantic Bight 



iContribution No. 588 of the Marine Sciences Research Cen- 

 ter, State University of New York, Stony Brook, NY. 



^Marine Sciences Research Center, State University of New 

 York, Stony Brook, NY 11794-5000; present address: 

 Chesapeake Biological Laboratory, University of Maryland, 

 Solomons, MD 20688. 



^Marine Sciences Research Center, State University of New 

 York, Stony Brook, NY 11794-5000. 



Manuscript accepted November 1987. 

 FISHERY BULLETIN; VOL. 86, NO. 2, 1988. 



midway over the continental shelf (see also Morse 

 et al. 1987). They further proposed that the 

 spring-spawned larvae are transported north- 

 ward in the slope waters and then move inshore, 

 spending their first summer in the bays and estu- 

 aries of the Middle Atlantic Bight. Summer- 

 spawned larvae, according to Kendall and Wal- 

 ford, spend their first summer at sea or enter the 

 estuaries of the Middle Atlantic Bight only 

 briefly before migrating southward with the 

 onset of winter. A minor spawning season extend- 

 ing from September to November off the coast of 

 Georgia and Florida (Collins and Stender 1987) 

 involves fish resident to the South Atlantic Bight 

 (Kendall and Walford 1979). 



The purpose of this study is to evaluate Kendall 

 and Walford's hypothesis by back-calculating the 

 spawn dates of young-of-the-year (YOY) bluefish 

 that have recruited to inshore waters, from the 

 number of grov^i;h increments in their otoliths. 

 First, we describe the timing and pattern of re- 

 cruitment of YOY bluefish to one segment of the 

 mid-Atlantic coastline: Long Island, NY. If 

 spawning is episodic, and if YOY bluefish from 

 each spavining period enter New York waters, 

 then length-frequency distributions of field col- 

 lections should be multimodal. Next, we verify 

 that otolith increment deposition has a daily peri- 



237 



