Able et a!.: Early life history of Centropristis striata 



435 



Large numbers of 0+ individuals were found in in- 

 tensive fall surveys in shallower inner continental 

 shelf waters off Massachusetts (Figs. 9 and 10). In 

 the winter, no age 0+ individuals were collected in 

 inner continental shelf waters off New Jersey (Figs. 

 8 and 10). Most individuals in the winter (January- 

 February) offshore surveys were collected near the 

 edge of the continental shelf. In spring (March-April) 

 surveys over the continental shelf, age 0+ individu- 

 als were evident over most depths. Most of these fish 



were found south of Delaware Bay (Fig. 10), some at 

 a variety of depths off New Jersey. No individuals 

 were collected in inshore spring (April-May) surveys 

 of Massachusetts coastal waters. 



Growth 



The 1992 year class attained sizes of 18-101 mm TL 

 by October after spawning, which occurred prima- 

 rily in August (Figs. 4 and 5; Tables 2 and 3). Our 

 estimates of growth rate are confounded somewhat 

 by the occurrence of two length modes of 0+ benthic 

 juveniles (Fig. 4), but calculations, based on the pro- 

 gression of these modes through October, yielded 

 growth rate estimates of 0.45 mm/day for the first 

 and 0.42 mm/day for the second length mode. The 1974 

 year class appeared to have reached similar lengths by 

 the fall (Fig. 6). In both 1974 and in more recent year 

 classes, sizes of fall fish and those reappearing the fol- 

 lowing spring were similar (Figs. 5 and 6), indicating 

 very little growth over the intervening winter. 



Growth resumed at a relatively fast rate in the 

 spring and continued through the summer. Based on 

 monthly increases (April-September, Fig. 5) in mean 

 size, growth rate was 0.77 mm/day during the pe- 

 riod. By July, approximately one year after spawn- 

 ing, these fish were 70-180 mm TL (Fig. 5). By Sep- 

 tember, when these fish were approximately 14—17 

 months old, they were 134-251 mm TL. A similar 

 pattern was evident for 1974 (Fig. 6). 



Habitat 



Juveniles (age 0+) were collected and observed in a 

 variety of habitat types both on the continental shelf 

 and in the estuary. Densities of age 0+ individuals 

 were similar between the inner continental shelf 

 (Beach Haven Ridge) and estuarine study sites in 

 the fall (August and September). When all the val- 

 ues for all habitats were combined, they were virtu- 

 ally identical with 0.33 (±0.007) ind-mr 2 in the estu- 

 ary (1-m beam trawl, /i = 144) and 0.32 ind-m -2 

 (±0.006) on the inner continental shelf (2-m beam 

 trawl, n=57) (Table 1). Age 0+ individuals, both on 

 the inner shelf and in the estuary, were found in 

 habitats with some structure. Visual observations 

 and video records provided evidence that individu- 

 als occurred in large linear accumulations or "wind- 

 rows" of the Atlantic surfclam valves, Spisula soli- 

 dissima, during the day in depths of 14-20 m on the 

 inner continental shelf near Beach Haven Ridge in 1991 

 and 1992 (Petrecca 4 ). Estimates made from video- 



4 Petrecca, R. Institute of Marine and Coastal Sciences, Rutgers 

 Univ., New Brunswick, NJ 08903. Personal commun., 1992. 



