Sadovy et al Age and growth of Epinephelus guttatus in Puerto Rico and St Thomas 



521 



ing aggregation area. To reach the bank, this fish must 

 have crossed water of at least 194 m depth, a substan- 

 tial depth for similar-sized individuals of this species 

 (Sadovy et al., unpubl. data). 



During the tagging study, significant data loss oc- 

 curred; in approximately 60% of tagged fish resighted, 

 the identifying number of the dorsal tag had detached, 

 leaving behind a monofilament anchor partially em- 

 bedded in dorsal musculature. On the other hand, 

 resightings of fish marked with abdominal tags in- 

 dicated that all had retained both the numbered tag 

 anchor and the attached color streamer. 



Data for age-groups of recaptured fish indicated that 

 no more than one opaque zone is deposited annually, 

 although sample size was limited. Opaque zone forma- 

 tion had begun in or after February, had terminated 

 prior to August, and occurred somewhat later in the 

 year in older age-groups. 



Recaptures were initiated as early as 5 months after 

 tagging because individuals typically disappeared from 

 the immediate study site within a few months of cap- 

 ture. Results covering less than a 12-month field period 

 should be treated with caution, although all results 

 were consistent with the marginal increment analysis 

 in terms of both the temporal nature of opaque zones 

 and the time of their annual deposition. 



Age and growth 



For Puerto Rico, the FL/OR relationship is 

 FL = 33.2180 -H 3.0743 OR (r2 0.76; N 624). 



GROWTH CURVES for Epinephelus gultalus 

 PUERTO RICO 



Nt624 

 • BACK- CALCULATED 

 O OBSERVED 

 - THEOBETICAL 



J STANDARD DEVIATION 

 |1S.dl 



AGE I years I 



Figure 5 



Empirical, back-calculated, and theoretical (von Berta- 

 lanffy) growth curves for Epinepheliis guttatus from 

 Puerto Rico. 



Table 2 shows the mean back-calculated lengths for 

 ages 1-17 years from 624 fish. The following growth 

 parameter estimates were obtained from the von 

 Bertalanffy growth function (with asymptotic SE in 

 parentheses): 



L^ = 514.5mmFL (6.29) 



K = 0.1013 (0.003765) 



to = -2.944 (0.1357). 



parentheses): 



L^ = eOl.OmmFL (32.82) 



K = 0.0705 (0.009954) 



to = -4.690 (0.5920). 



Figure 6 shows the empirical mean lengths and their 

 standard deviations, as well as back-calculated and 

 theoretical growth curves, for St. Thomas. 



Figure 5 shows empirical mean lengths and their 

 standard deviations, as well as back-calculated and 

 theoretical (VBGF) growth curves, for Puerto Rico. 



For St. Thomas the FL/OR relationship is 

 FL = 94.7206-1-2.4757 OR (r^- 0.68; A^ 162). 



Table 3 shows the mean back-calculated lengths for 

 age-groups 1-18 from 162 fish. The following growth 

 parameter estimates were obtained from the von 

 Bertalanffy growth function (with asymptotic SE in 



For Puerto Rico, the OW/FL relationship is 

 OW = 1.4205 + 0.0108 FL (r2 0.93; N 315; Fig. 7). 



For St. Thomas, the OW/FL relationship is 

 OW = 0.5591 -H 0.0049 FL (r^ 0.93; A^ 101). 



When mean back-calculated fork lengths for annuli 

 I-V for age-groups 1-14 from Puerto Rico and St. 

 Thomas are plotted (Fig. 8), two points are worthy of 

 note. If regressions for each annulus are calculated for 

 all available ages up to age-group 14, all are statistically 



