Able et al : Use of ocean and estuanne habitats by young of the-year Pomatomus saltatrix 



209 



10 

 5 

 



10-1 

 5 

 



250-1 

 125 





 200 

 100 





 200 

 100 







Ocean Beaches 



June 

 fl-0 



July 

 n=10 



I ^1 W i W I 



August 

 n=319 



flW-r 



September 

 n = 613 



iTrrrTTTTTTTTTTTTT 



1 4 7 10 13 16 19 22 25 28 



Jlkn 



October 

 n = 459 



1 1 1 1 1 1 1 1 1 1 1 M 1 M 1 1 ri I rn i ii 1 1 



1 4 7 10 13 16 19 22 25 28 



10 

 5- 

 



November 

 n = 1 



I I I M I I I I I ri M I I I I I I I I I 



Estuarine Beaches 



10 

 5 



I I I I I I I I I I I I M I I I I I I I I M I I I M I 



1 4 7 10 13 16 19 22 25 28 



June 

 n=5 



Jin 



lOn 

 5 



TTTTTTTTTTTTTTTTTTT 



1 4 7 10 13 16 19 22 25 28 



July 

 n = 7 



M I I I I I M I M I I I I M I 



1 4 7 10 13 16 19 22 25 28 



I rl fl I I n I 



I I I M I M I I M I M I I I I I 



1 4 7 10 13 16 19 22 25 28 



20 

 10 



I I M I M I I I I I I I I I 0- 



1 4 7 10 13 16 19 22 25 28 



m -I 



August 

 n = 32 



I I I I M I I I M I I I I I M M I II I I I [ 1 I 



1 4 7 10 13 16 19 22 25 28 



10 

 5 

 



10 

 5 

 



September 

 n = 28 



TTTTTrrrrTTnTTTTTTTTTrrrrrrn 

 1 4 7 10 13 16 19 22 25 28 



October 

 n = 1 



M I I I I I I I I I I M n I I M I I I I I I I I I I 



1 4 7 10 13 16 19 22 25 28 



10 

 5- 

 



^4ovember 

 n = 



I I I I 1 1 I I I I I I I 1 1 I I I I I I I 1 1 I I 1 1 I I 

 1 4 7 10 13 16 19 22 25 28 



1 4 7 10 13 16 19 22 25 28 



Fork length (cm) 



Figure 7 



Size composition of young-of-year bluefish from southern New Jersey ocean 

 beaches and the adjacent Great Bay estuary by month during 1998. 



Middle Atlantic Bight (McBride et al., 1993; Hare and 

 Cowen, 1996; Juanes et al., 1996; Able and Fahay, 1998), 

 it appears that multiple cohorts occur in ocean habitats as 

 well, based on the occurrence of the appropriate-size indi- 

 viduals in inner continental shelf (Fig. 5) and ocean beach 

 (Figs. 6 and 7) sampling sites and in many of the same sites 

 in the study area based on further extensive collections in 

 1999 and 2000 (Rowe et al.^). 



In most years the smaller individuals of the presumed 

 summer-spawned cohort were more abundant in ocean 

 habitats. Others have suggested that summer-spawned in- 

 dividuals may be more abundant in the ocean (Kendall and 

 Walford, 1979; Wilk, 1982) than in the estuary. Gear biases 

 could influence the size of the YOY collected, as indicated by 

 McBride and Conover ( 1991) for beach seines; therefore it is 

 difficult to separate the effects of gear versus habitat to de- 

 termine what is responsible for the average larger YOY col- 

 lected in the ocean by otter trawl from the smaller average- 



size individuals collected on ocean beaches with seines. 

 However, the occurrence of the largest fish in the deepest 

 waters (21-27 m) suggests that habitat preference may be 

 involved. A similar pattern was observed by Munch and 

 Conover (2000), who found that the larger spring-spawned 

 individuals were usually found in deeper waters than those 

 for smaller summer-spawned individuals. 



The contribution of the smaller bluefish cohort! s) to the 

 population dynamics of the species in the Middle Atlantic 

 Bight is unknown. The occurrence of very small (<50 mm) 

 YOY bluefish in late summer occurred in a number of years 

 during the study and subsequently (Rowe et al.^). These 

 fish may represent late spawning or slow growth. They, 

 along with the relatively small pelagic juveniles present in 

 the water column in inner continental shelf waters in the 

 study area at the same time (Rowe and Able, unpubl. data), 

 may not contribute to the adult population because they 

 enter the fall at relatively small sizes and may not survive 



