FISHERY BULLETIN: VOL. 82, NO. 3 



deposits and suitable for age determination. 

 Lengths varied within age classes and length 

 ranges overlapped between age classes (Tables 2, 

 3, 4). For example, males with three annuli 

 (translucent bands) ranged from 258 to 537 mm 

 FL and those with four annuli ranged from 250 

 to 549 mm FL. There was, however, a general 

 trend of increasing modal length with increase in 

 age. 



The gray triggerfish is a moderately long-lived 

 species. The oldest male was estimated to be 13 yr 

 old (544 mm FL) and the oldest female was 12 yr 

 old (561 mm FL). 



The back-calculated and empirical sizes at age 

 are presented in Tables 5, 6, and 7. The average 



mean back-calculated length at age for males was 

 slightly (5-50 mm FL) larger than that for fe- 

 males at age 1-9, after which the females were 

 larger. Only three fish were collected that were 

 older than 9 yr; thus the reversal of the trend is 

 probably an artifact caused by few samples. 



The von Bertalanffy growth parameters varied 

 slightly between males, females, and all fish. The 

 von Bertalanffy equations were: 



males It = 491.9(1 - e 



0.382(^-0.227) 



), 



females l t = 437.5(1 - e -o.383«-o.i50) )) 

 all fish l t = 466.0(1 - e o.382U-o.i89> K 



TABLE 2. — Length composition, in percent, of male gray triggerfish by age groups from 



northeast Gulf of Mexico, 1979-82. 



TABLE 3. — Length composition, in percent, of female gray triggerfish by age groups from northeast 



Gulf of Mexico, 1979-82. 



TABLE 4. — Length composition, in percent, of gray triggerfish (all fish) by age groups from northeast Gulf of 



Mexico, 1979-82. 



488 



