Crabtree et al,: Life history of Tmchtnotus lakatus 



33 



dent sources, such as charterboats. Wo did not sample any 

 permit from the commercial fishery, which principally tar- 

 gets smaller fish as a result of the maximum size limit of 20 

 inches (508 mm FL) for permit caught by commercial ves- 

 sels. Ai'mstrong et al.- reported that most han-ested permit 

 in Florida were <440 mm. In contrast, our sample contained 

 many fish larger than 600 mm. The high proportion of large 

 permit in our sample could reflect a tendency for charter- 

 boats in the Florida Keys to select larger permit than those 

 selected by more typical anglers statewide. Ai-mstrong et 

 al.'s^ assessment was based on more systematic and state- 

 wide sampling than ours, and the differences between their 

 sample and ours probably reflects our attempt to obtain a 

 sample of all available size classes rather than a represen- 

 tative sample of the Florida hai-vest. 



Age and growth 



The oldest permit in our sample was estimated to be 23 

 years old. Although we examined many relatively large 

 permit, larger fish than those we examined have been 

 caught. Robins ( 1992) reported that permit can reach 1100 

 mm FL and a weight of 23 kg; consequently, permit lon- 

 gevity probably exceeds our estimate of 23 years. There 

 are no other estimates of age and growth of permit for 

 comparison, but our longevity estimates are similar to 

 those determined from sectioned otoliths for other caran- 

 gids. Manooch and Potts (1997) aged greater amberjack 

 and found fish as old as 17 years. The oldest carangid 

 yet studied is the trevally, Caranx georgianus, reported to 

 reach an age of 46 years (James, 1984). The much smaller 

 Florida pompano has been reported to reach an age of 7 

 years (Hood et al.-^). 



Our estimates of the von Bertalanffy growth model pa- 

 rameters are within the range of those reported for other 

 carangids (James, 1984; Sudekum et al., 1991; Manooch 

 and Potts, 1997). We found no significant differences be- 

 tween male and female von Bertalanffy growth models, 

 but the significance level (P=0.059) was close enough to 

 0.05 to cause us to suspect that a difference might exist. 

 Hood et al.'^ also found no sex-specific differences in growth 

 models for pompano. 



Sexual maturation 



We sampled relatively few permit between 300 and 500 

 mm long, the size at which sexual maturity is reached. The 

 lack offish in this critical size range resulted in the knife- 

 edge maturity curves. Larger sample sizes are needed to 

 derive more precise estimates of age and size at sexual 

 maturity. In an assessment of the status of permit stocks 

 in Florida, Armstrong et al.- assumed that permit mature 

 at about 440 mm FL on the basis of limited biological 

 data available at the time. Our estimates of length at 50% 

 maturity are larger: 486 mm for males and 547 mm for 

 females. As a consequence of Florida's 20-inch (508-mm) 

 recreational and commercial maximum size limit, most of 

 the permit harvested are sexually immature (Armstrong 

 etal.2). 



Spawning 



We believe that permit spawn over artificial and natural 

 reefs in the waters of the middle and lower Florida Keys 

 because ovaries of fish caught over these structures con- 

 tained oocytes in the final stages of maturation and POFs. 

 Other researchers have inferred that permit spawn in 

 nearshore waters from the capture of early-stage lai-vae 

 (Fields. 1962; Finucane, 1969). Permit ovaries that con- 

 tained fresh POFs and oocytes in the final stages of mat- 

 uration also contained clutches of early- and mid-stage 

 vitellogenic oocytes, suggesting that permit are multiple- 

 batch spawners. 



Spawning occurred at least during May-June in the 

 Florida Keys during 1995-97. Juvenile length frequen- 

 cies in the Keys suggest a more prolonged spawning sea- 

 son — perhaps even year-round spawning; however, the 

 prolonged presence of small juveniles could also be attrib- 

 uted to variable juvenile growth rates rather than extend- 

 ed spawning. This question could be resolved by direct ag- 

 ing of juveniles to evaluate growth rates. Our sample of 

 adult permit may have been too small to reveal low levels 

 of spawning outside of spring and early summer, and no 

 mature permit were collected during January or February. 

 On the basis of seasonal occurrence of juveniles, Finucane 

 ( 1969) suggested that permit spawn during April-June in 

 the Tampa Bay area, but Fields (1962) found juveniles 



3 Hood. P. B.. D. T Menyman. and D. J. Harshany 1999. Age, 

 growth, mortality, and reproduction of the Florida pompano, 

 Trachinotus carolinus, from Florida waters. Unpubl. manu- 

 script. Florida Marine Research Institute, 100 Eighth Avenue 

 SE, St. Petersburg, FL. 



