16 



Fishery Bulletin 91(1), 1993 



ing eight stations each had <5 lar- 

 vae. There were eight different 

 birthweek cohorts in January and 

 nine in February. The principal 

 cohorts in January were those of 

 weeks beginning 20 and 27 De- 

 cember, which together contrib- 

 uted more than 88% of all larvae 

 collected in the ocean (Fig. 8). 

 These cohorts were the most im- 

 portant contributors to larvae re- 

 cruited during the week of great- 

 est abundance, 23 March 

 (Table 1, Fig. 2). During Febru- 

 ary, larval cohorts were princi- 

 pally from birthweeks beginning 

 20 December-23 January. Larvae 

 from these cohorts were caught 

 later in the estuary and contrib- 

 uted heavily to the abundance 

 peaks of 23 March and 13 April 

 (Table 1). 



A Kolmogorov-Smirnov two- 

 sample test (Sokal & Rohlf 1981 ) 

 was used to compare larval 

 birthdate distributions for a 

 3-week spawning period, 13 De- 

 cember-2 January (Figs. 5&8), 

 for larvae collected during Janu- 

 ary-February in the ocean and 

 February-March in the estuary. 

 There was no significant dif- 

 ference (max. diff. = 0.108, 

 P>0.05) between birthdate distri- 

 butions of 98 larvae collected in 

 the ocean in January and 109 col- 

 lected in February. There was 

 also no significant difference be- 

 tween the pooled birthdate dis- 

 tribution data for larvae collected 

 in the ocean in January and 

 February (rc=207) and for 134 lar- 

 vae collected in the estuary at 

 Pivers Island (max. diff. = 0.180, 

 P>0.05). 



Growth rate 



The overall growth rate of larval 

 spot was estimated from 312 es- 

 tuarine and 351 oceanic speci- 

 mens combined. Larvae ranged from 9 to 108 d and 2.1 

 to 22.2 mmSL (Fig. 9). From the Laird-Gompertz model 

 (Fig. 9), we predicted that spot grew from 1.2mm at 



Figure 7 



Contour plots of the mean age (d) on (A) 12-13 January, and (B) 2-5 February, and 

 mean standard length (mm) on (C) 12-13 January and (D) 2-5 February, of spot 

 Leiostomus xanthurus larvae collected off the North Carolina coast in 1988. + indicates 

 no larvae collected. 



hatching to 19.1 mm in 95 d, an overall average growth 

 rate of 0.188mm/d. The size at hatching, estimated 

 from the Laird-Gompertz model (1.2mmSL), was less 



