246 



Fishery Bulletin 90(2|. 1992 



AGE (yrs) 



Figure 2 



Observed ages (years) and total lengths (mm), and predicted 

 growth modeled for jewfish collected from the eastern Gulf 

 of Mexico. Parameters for the von Bertalanffy growth model 

 are L„=2006mmTL, K = 0.126/year, and t„ = -0.49 year 

 {N 382). 



Fig. 2). Average observed and predicted (von Berta- 

 lanffy equation) sizes-at-age were similar between 

 sexes (Table 1). Results of likelihood ratio tests indi- 

 cated no significant differences between sex-specific 

 estimates of L^ (x^ 0.136, df 1, P>0.70), K (x^ 4.0 x 

 10-5, df 1, P>0.90), or to (jc^ 0.138, df 1, P>0.70). 

 Estimates of the growth equation parameters (asymp- 

 totic standard error) for pooled length and age data 

 were L^ =2006mmTL (23.3), K = 0.126/year (0.0057), 

 and to = -0.49 years (0.200). 



The relationships of whole and gutted weight (kg) to 

 total length (mm) were 



WW = 1.31 X 10-8TL3056 (jv 66, r^ 0.964) 

 GW = 2.94 X 10-8TL2911 (iv 402, r'^ 0.941). 



Gutted and whole weights were linearly related (A^ 50, 

 r2 0.995) as follows: 



Jewfish spawn during June-December in the eastern 

 Gulf of Mexico, with peak activity during July- Sep- 

 tember (Fig. 3). Ripe males and females first appeared 

 in our collections during June. Nearly all gonads col- 



I MATURE RESTING 



g RIPENING 



□ RIPE 



Q POST SPAWNING 



JAN FEB MAR APR MAY JUN JUL AUG SEP OCT NOV DEC 

 MONTH 



g MATURE RESTING 



n RIPE 



Q POST-SPAWNING 



JAN FEB MAR APR MAY JUN JUL AUG SEP OCT NOV DEC 

 MONTH 



Figure 3 



Monthly distribution of gonad classes for mature (upper) male 

 (A^ 66) and (lower) female (A^ 86) jewfish collected from the 

 eastern Gulf of Mexico. Histological criteria for gonad classes 

 correspond to Moe's (1969) descriptions for red grouper. 



lected from mature fish in July, August, and September 

 were classified as ripe. Most spawning appears to end 

 by October, although a ripe male was collected in 

 November and another in December. Spent fish were 

 collected in August (one male) and October (one 

 female). No transitional fish were found. 



Male jewfish become sexually mature at a slightly 

 smaller size and younger age than females. Male jew- 

 fish were first mature when about 1100-1150mmTL 

 at 4-6 years of age. All males <1150mmTL (A'^ 6, 

 795-llOOmm) were immature, whereas all larger 

 males in our samples (A^ 55, 11 55-2057 mm) were 

 mature. Both 3-year-old males sampled were imma- 

 ture, whereas one large (1184 mmTL) 4-year-old male 

 was mature. Fifty percent of males 5 or 6 years old 

 (3 of 6 individuals) and all males age 7 or older (A'^ 31) 

 were mature. Female jewfish first mature when about 

 1200-1350 mmTL at age 6 or 7. All females <1225 

 mm (A^ 21, 338-1218mm) and <6 years old (A^ 17, 0-5 

 yr) were immature. All larger (A'^ 90, 1350-2155 mm) 

 and older (A'^ 68, 8-37 yr) females sampled were 

 mature. 



