GRIMES and HUNTSMAN: REPRODUCTIVE BIOLOGY OF THE VERMILION SNAPPER 



females may spawn several times per season, 

 fecundity estimates were from ovaries collected 

 early in the spawning season (May and June) and 

 all classes of maturing ova were counted. 



In Table 5, fecundity was separately regressed 

 on total length (millimeters), weight (grams), and 

 age (years) and, as expected, fecundity increases 

 as a function of all three correlates. Fecundity 

 increases so markedly in larger (older) fish (Figure 

 6) that semilog models were needed to adequately 

 describe the relationship between fecundity and 

 length, weight, and age. Length and weight are 

 approximately equally good predictors of fecun- 

 dity (r = 0.864 and 0.863, respectively). First 

 spawners probably are about 205-275 mm TL and 

 produce between 16,800 and 41,700 eggs. This es- 

 timate assumes that spawning extends from late 

 June through September for young fish (age 2-4), 

 that first spawning occurs in the third or fourth 

 year (186-256 or 256-324 mm TL), that scale an- 

 nuli form in March (Grimes 1978), and that ap- 

 proximately 25% of annual growth occurs from 

 annulus formation to late June. 



Table 5. — Functional equations for fecundity in vermilion 

 snapper. Age (A ) determined from scales. 



Predictof 



Equation 



Total length (nnm) 

 Age (yr) 

 Weight (g) 



F = exp(7.07 + 0.01 ari) 



F = exp (7 57 * 87aA) 

 F = exp (10 21 + 0.002VV) 



DISCUSSION 



Spawning Seasonality 



The conclusion that spawning occurs from late 

 April through September is corroborated by 

 Longley and Hildebrand's (1941) statement that 

 spawning took place in summer around the Tor- 

 tugas. Powles^ and Fahay (1975) reported that 

 larvae were collected at the surface off South 

 Carolina and Georgia in June and July, and 

 Laroche (1977) described a larval series collected 

 off Georgia in August. Walker (1950), however, 

 reports collecting vermilion snapper in spawning 

 condition off North Carolina in February. Erdman 

 (1976) sampled 400 vermilion snapper in the 

 northeastern Caribbean and found fish in spawn- 

 ing condition January through June. Monroe et al. 

 (1973) collected a ripe female in November off 



^H. Powles, Fishery Biologist, South Carolina Marine Re- 

 source Center, Charleston, S.C., pers. commun. May 1975. 



20 



Fecundity - e 



15 



o 



X 



o 



z 



< 

 > 



o 



o 



z 



10 



7.065 + .013 TL 



n=41 

 r = .863 



• • 



_L 



J_ 



200 300 400 500 600 



TOTAL LENGTH (mm) 



Figure 6. — The relationship of fecundity to total length of 

 female vermilion snapper. 



Jamaica and suggested, on the basis of these and 

 more extensive data for other reef species, that 

 spawning probably occurs year-round in the 

 Caribbean, but that peak spawning is in winter 

 where surface temperature is about 26.5° C. The 

 larvae reported on by Fahay (1975) and Laroche 

 (1977) were collected at 27° and 26.5° C, respec- 

 tively, and we collected ripe fish off North 

 Carolina when sea surface temperature was be- 

 tween 26° and 27° C. 



It appears that spawning of vermilion snapper 

 off North Carolina and South Carolina is re- 

 stricted to warm months (late April or May- 

 September), yet spawning may occur almost 

 year-round in the Caribbean (Monroe et al. 1973; 

 Erdman 1976). Similar life history variations in 

 response to local environmental conditions are re- 

 ported by Leggett and Carscadden (1978) for 

 American shad. 



143 



