Hood and Johnson: Life history of Rhomboplites aurorubens 



833 



dian values from January to May and low values in 

 July and August (Fig. 3). 



Ages ranged from 1 to 13 years. Most males (74%) 

 and females (77% ) were found to be between ages 4 

 and 7 (Fig. 4). Initial growth of vermilion snapper 

 was rapid, and fish attained a mean length of 211 

 mm TL during their second year (age 1, Table 3). 

 However, subsequent increases in length were low 

 (<33 mm). Likelihood ratio tests did not show a dif- 

 ference between the male and female von Bertalanffy 

 growth models ( x-=0.92, df=3, P>0.5 ). The estimated 

 von Bertalanffy growth parameters (standard error) 

 for all aged fish (n=841) were L„=298(5.0), K=0.25 

 (0.04), and ^o=-3.9 (0.85). Predicted lengths at age 

 were similar to mean lengths at age (Table 3; Fig. 5); 

 however, because of high variability in length-at-age 

 data, the correlation coefficient for estimated growth 

 was low (adjusted r^=0.26), suggesting that age is 

 not a good predictor of length. 



Mortality 



Catch length-frequency data were transformed into 

 age frequencies by using age-length keys constructed 



cfl 150 



-^ 



Age (yr) 



Figure 4 



Age distribution of male (open) and female (hatched! 

 vermilion snapper from the eastern Gulf of Mexico. 



from our ages. Full recruitment into both the recre- 

 ational and commercial fisheries occurred at age 6. 

 Survivorship (standard error) estimates determined 

 by using the Chapman-Robson method were 0.619 

 (6.0002) and 0.613(0.0001), respectively Instanta- 

 neous mortality estimates (Z=-ln survivorship) were 



