30 
Fishery Bulletin 1 13(1) 
Table 1 
Number of samples of first dorsal spines that were available for our age and growth 
study of gray triggerfish (Balistes capriscus) collected during 1990-2012, primar- 
ily from fisheries landings along the coast of the southeastern United States. Five 
samples were collected during fishery-independent trap sampling off Florida’s east 
coast. Values in the columns for the recreational sector include samples from both the 
headboat component and the component that includes private recreational boats and 
charter boats. Samples were collected in the following states: Florida (FL), Georgia 
(GA), North Carolina (NC), and South Carolina (SC). 
Commercial 
Recreational 
Year 
FL-GA 
NC 
SC 
FL-GA 
NC 
SC 
1990 
18 
1991 
5 
33 
4 
1994 
1 
1997 
2 
2001 
2 
2002 
8 
5 
2003 
43 
2004 
3 
188 
60 
2005 
386 
157 
1 
2006 
327 
140 
91 
7 
13 
2007 
493 
203 
17 
36 
26 
2008 
676 
88 
6 
13 
15 
2009 
648 
92 
5 
6 
21 
2010 
695 
297 
1 
69 
28 
2011 
1052 
220 
3 
36 
23 
2012 
5 
lina and South Carolina. Approximately 10% of aging 
samples were from Florida, and the majority of those 
samples were from the headboat component catches of 
the recreational sector. Translucent zones were counted 
on 6267 (97.7%) of the 6419 sectioned spines. Sections 
from the other 152 spines (2.3%) were determined to be 
unreadable and were excluded from this study. 
For our analysis of increment periodicity, we as- 
signed an edge type to all 6267 samples. Translucent 
zones were present on the spine marginal edge in all 
months (Fig. 1); the highest percentage of gray trig- 
gerfish with translucent zones occurred from March 
to June and the lowest from September to February; 
peak formation occurred in April and May (Fig. 1A). A 
clear pattern of the width of the opaque margin was 
noted (Fig. IB). The narrowest opaque margins (e.g., 
edge type 2) occurred during June-September, which 
follows the period of peak formation of the translucent 
zone. The widest opaque margins occurred during De- 
cember-March, when the translucent zones start form- 
ing again. We concluded that translucent zones on gray 
triggerfish spines were annuli. Chronological ages re- 
sulting from edge analysis were assigned as follows: 
for fish that were caught from January to June and 
had an edge type of 3 or 4, the chronological age was 
the annuli count increased by one; for fish that were 
caught during the same period and had an edge type 
of 1 or 2, the chronological age was equivalent to the 
annuli count; and, for fish that were caught from July 
to December, the chronological age was equivalent to 
the annuli count. 
Growth increments of gray triggerfish were moder- 
ately difficult to interpret. Based on Campana’s (2001) 
acceptable values of APE (5%), agreement was moder- 
ate across all 3 readers (MLB-JCP APE=11%, n = 198; 
MLB-MC APE=9%, n=100; JCP-MC APE=12%, n = 100; 
overall APE=11%). Percent agreement values between 
the 2 primary readers (MLB and JCP) were low (34%) 
but increased for estimates within (±) 1 year (67%) and 
within (±) 2 years (86%). An age bias plot indicates 
that the second primary reader, in comparison with the 
first primary reader, underestimated gray triggerfish 
ages, starting at age 5 (Fig. 2), but also shows that 
the average difference between readers for ages 5-10 
was only 1.2 years. These results indicate acceptable 
between-reader agreement; hence, we included ages 
from all 3 readers in further analyses. 
Growth 
Gray triggerfish in this study (n=6267) ranged in size 
from 173 to 567 mm FL and in age from 0 to 15 years. 
A single age-0 fish was captured by fishery-indepen- 
