Crabtree et a\ Life histoid of Tmchlnotus falcatus 



29 



200 400 600 800 1000 1200 



25^ 



200 400 600 800 1000 1200 



Fork length (mm) 



E 

 2 



20 



15 



10 



5 







25 



20 



15 



10 



5 







males 



n=124 



10 15 20 25 



females 

 n^127 



10 15 20 25 



Age (yr) 



Figure 1 



Fork lengths (mm) and ages (years) of male and female permit. Trachinotus falcatus, sampled from 

 South Florida waters. 



group of fish was systematically excluded from the age- 

 and-grovvth analysis. 



Annulus formation in permit occurs during spring and 

 early summer. The percentage of permit with an annulus 

 on the otolith's margin was greatest during summer and 

 least during October-March, suggesting that annulus for- 

 mation is seasonal and that annuli first become visible 

 during late spring or early summer (Fig. 3). A single 

 OTC-injected permit was successfully held for a sufficient 

 length of time to be useful in age validation. This fish was 

 captured and injected with OTC on 17 June 1993. The fish 

 was sacrificed on 30 January 1996 and measured 600 mm 

 in length. After 31 months in captivity, which included two 

 spring-summer periods, the fish had formed two annuli, 

 a number that is consistent with our hypothesis that a 

 single annual mark forms annually during late spring or 

 early summer. Also visible immediately before the OTC 

 mark was an annulus that was probably formed during 

 late spring of 1993, just prior to capture and OTC injec- 

 tion. Moreover, there was a wide margin subsequent to 

 the last annulus that is consistent with the six or more 

 months of otolith growth after formation of the final an- 

 nulus in late spring or early summer of 1995. 



Estimated ages of 298 permit ranged from to 23 years 

 for fish 102 to 900 mm long. Permit grew rapidly until 

 about age five, and then growth slowed considerably (Ta- 

 ble 1, Fig. 4). Most of the fish in our sample were less than 

 10 years old, although fish 10-15 years old were common. 

 The oldest permit examined was a 23-year-old I781-mm) 



male (Table 1). Estimates of von Bertalanffy growth model 

 parameters are presented in Table 2. The growth models 

 for male and female permit were not significantly differ- 

 ent (approximate randomization test, P=0. 059). 



Sexual maturation 



We estimated that 50'7f of the males in the population 

 reached sexual maturity by 486 mm and an age of 2.3 

 years, and 509^ of the females in the population reached 

 sexual maturity by 547 mm and an age of 3.1 years (Table 

 3). The smallest sexually mature male in our sample was 

 449 mm long, and the youngest sexually mature male 

 was 3 years old. Our estimate of the age at 50'7f maturity 

 for males was less than the age of the youngest mature 

 male observed. This knife-edge maturity curve could be 

 an artifact of our small sample size. The smallest sexually 

 mature female in our sample was 476 mm long, and the 

 youngest sexually mature female was 3 years old. All of 

 the ovaries we examined contained primary-growth-stage 

 oocytes. Cortical alveolar-stage oocytes occurred only in 

 ovaries from permit larger than 450 mm and older than 

 2 years and were common only among permit larger than 

 500 mm and older than 3 years. Vitellogenic oocytes were 

 found only in ovaries from fish larger than 550 mm and 

 older than 3 years and were common only among permit 

 larger than 600 mm. The length and age at which vitel- 

 logenic oocytes were commonly found agrees well with our 

 estimate of the length and age at which 50% maturity was 



