Manickchand-Heileman and Phillip Age and growth of Eptnephelus flavolimbatus and Mycteroperca inteistitialis 



295 



pers in higher latitudes, e.g. M. phena.x in the 

 South Atlantic Bight (Matheson et al., 1986), 

 E. itajara (Bullock et al., 1992) and M. micro- 

 lepis (Hood and Schlieder, 1992) in the eastern 

 Gulf of Mexico, and M. bonaci in south Flor- 

 ida (Crabtree and Bullock, 1998). For the two 

 species in our study, annulus formation may 

 be associated with changes in environmental 

 factors, notably reduced bottom temperature 

 during the wet season. On the continental 

 shelf, where our study was conducted, bottom 

 temperature has been found to decrease to 

 a minimum of about 22"C in the wet season 

 (GadeS). 



Annual rings were found in otoliths of yel- 

 lowedge and yellowmouth groupers in other 

 geographical areas, although time of annulus 

 formation differed, which may be attributed 

 to differences in annulus measurement tech- 

 niques. For yellowedge grouper in the South 

 Atlantic Bight, annulus formation occurred in 

 March-September and coincided with time of 

 peak spawning (Keener, 1984), whereas in the 

 eastern Gulf of Mexico it occuiTed from May to Novem- 

 ber ( Bullock and Godcharles'' ). The yellowmouth grou- 

 per formed annuli in August-October in the eastern 

 Gulf of Mexico (Bullock and Murphy, 1994). 



Some backcalculated lengths were larger than 

 observed lengths, especially for the younger age 

 groups. This reverse "Rosa Lee" phenomenon may 

 have resulted from increased survival of fast-grow- 

 ing fish (Ricker, 1975). For the yellowmouth grouper. 



900 T 



E 600 



E 



° 300 



theoretical 



X observed 



i backcalculated 



-I- 



-I- 



-I- 



H 



5 10 15 20 25 30 35 40 45 



Age (yr) 



Figure 5 



Obsen'ed. backcalculated, and theoretical lengths at age for yellow- 

 mouth grouper, M. interftitialis. 



the small number offish available for ring measure- 

 ments may have also contributed to discrepancies in 

 the backcalculated lengths. 



The growth pattern of these two species is similar 

 to that reported for other gi-oupers, in that they are 

 long-lived and have low growth rates and high asymp- 

 totic lengths (e.g. M. pheiiax. Matheson et al., 1986; M. 

 hoiuici. Manooch and Mason, 1987, Crabtree and Bull- 

 ock, 1998; E. itajara. Bullock et al., 1992; M. micro- 



