Hood and Johnson: Life history of Rhomboplites aurorubens 



831 



served gonad and embedded in paraffin. We cut a 

 5.0-^m section from the sample, stained it with 

 Harris's haematoxyUn, counterstained it with eosin 

 (Humason, 1972), and examined it under a compound 

 microscope to determine sex and gonad developmen- 

 tal state. In addition, the frequency of oocyte devel- 

 opmental stages (including atretic bodies and 

 postovulatory follicles) was tabulated for approxi- 

 mately 300 oocytes from each ovary by using a com- 

 puter-driven data-acquisition software package 

 (Optimas Corp., 1996). Gonadal development classes 

 (Table 1) were determined by using modified classi- 

 fication schemes developed from West (1990) and 

 Wallace and Selman (1981) for females and from 

 Hyder( 1969) for males. 



Reproductive seasonality was determined by ex- 

 amining the monthly changes in gonad classes, the 

 monthly distribution of oocyte stages, and the 

 monthly changes in the gonadosomatic index (GSI). 

 The GSI was calculated by the following equation: 



GSI = gonad weight/i whole weight -gonad weight). 



If whole weight was not available, it was estimated 

 from TL. Batch fecundity was estimated by counting 

 hydrated oocytes following the gravimetric method 

 described by Hunter et al. (1985). The relation be- 

 tween fish weight and batch fecundity was examined 

 for a significant correlation by means of least-squares 

 regression analysis (SAS Institute, Inc., 1985). 



Results 



Collections 



We sampled 858 vermilion snapper that ranged from 

 192 to 585 mm TL. Most fish (87% ) were between 201 

 and 325 mm TL. Relationships between lengths, be- 

 tween lengths and weights, and between weights are 

 seen in Table 2. Male and female data were pooled for 

 the weight-length relationship because no significant 

 difference was found between slopes and y-intercepts 

 of sex-specific regression equations (analysis of covari- 

 ance, P=0.47 and 0.08, respectively). Most fish came 

 fi'om the recreational fishery (72=661) and ranged in 

 length from 192 to 400 mm TL (Fig. 2). Fish from the 

 commercial fishery (n= 168) ranged from 225 to 585 mm 

 TL. The mean length of recreationally caught fish (256 

 mm TL, SE=29) was significantly less than the mean 

 length of commercially caught fish (324 mm TL, SE=90; 

 t-test, P<0.001 ). The length-frequency distributions for 

 commercially and recreationally caught fish were sig- 

 nificantly different (r'=216, df=5, P<0.001). Fish ob- 

 tained fi-om the trawl survey (n=27) were small and 

 ranged in length from 205 to 253 mm TL. 



The mean length of males (256 mm TL, SE=4) was 

 not significantly different from that of females (261 

 mm TL, SE=3; t-test, P=0.315). Males (n =392) ranged 

 in length from 199 to 585 mm TL and females (/2=430) 

 from 192 to 518 mm TL (Fig. 2). The overall sex ratio 

 of males to females was 1:1.1 and was not signifi- 



