Condini et al.: Age and growth of Epinephelus marginatus in the southwestern Atlantic 
317 
Age (years) 
Figure 4 
Total lengths, measured in millimeters, at ages and a fitted von Bertalanffy 
growth curve for dusky grouper (Epinephelus marginatus ) specimens (n=189) 
caught at the Carpinteiro Bank in the southwestern Atlantic by small-scale fish- 
eries from 2008 to 2011. r 2 =coefficient of determination. 
bined evidence of the low availability of old fish with 
the rising fishing effort over the last 3 decades and the 
large proportion of young adult individuals sampled 
here, it is reasonable to suggest that this offshore pop- 
ulation may be undergoing overfishing. Unfortunately, 
there are no official fish landing records to allow an es- 
timation of capture trends over time. These data would 
be necessary to objectively infer the population status 
of dusky grouper in southern Brazil. 
The sampling conducted in 
the our study was restricted to 
Carpinteiro Bank, and that limit 
may cause concern because it is 
shallower (15-25 m) than the 
depths (up to 40-50 m) where 
larger groupers usually live 
(Heemstra and Randall, 1993). 
It is, therefore, plausible to ar- 
gue that ontogenetic migration, 
which is usual in epinephelids 
(Dahlgren and Eggleston, 2000), 
could be withdrawing large-size 
( >90 cm) fish from the exam- 
ined population because of their 
emigration toward waters with 
depths of 40-50 m. However, we 
posit that this notion is not the 
case for two main reasons. First, 
the continental shelf at the ex- 
treme southern part of Brazil 
basically is formed by sand bot- 
toms, where reefs and rocks are 
scarce (Calliari and Klein 1993). 
There are just a few rocky banks 
that may provide habitat for 
groupers, and they are found 
specifically between the 20- to 
30-m isobaths (Cardoso and Haimovici, 2011). Among 
these banks, Carpinteiro, Solidao, and Torres are the 
most visited by fishing boats (Cardoso and Haimovi- 
ci, 2011). Second, reproduction has been observed for 
dusky grouper in Carpinteiro Bank (Condini et al., 
2014), supporting the idea that the whole life cycle of 
the examined population occurs in this bank. Given 
these arguments, we believe that the relatively low 
abundance of older (> 15 years) individuals is an in- 
AGE: 4 
AGE: 5 
Ll 
n = 29 
IN OF 
IN OF 
m 
IN OF 
Sites 
n - 16 
X 
X 
AGE 6 
n-20 
HIL 
IN OF 
AGE: 7 
n=21 
! T 
IN OF 
Figure 5 
Comparison by age (3-7 years old) of average total length of dusky groupers (Epinephelus 
marginatus) collected from inshore (IN, black bars) and offshore (OF, open bars) habitats. 
Fish were collected from the inshore site, littoral rocky jetties near Patos Lagoon, from 2007 
to 2009 and from an offshore site of Carpinteiro Bank from 2008 to 2011. Error bars indicate 
95% confidence intervals. 
