312 
Fishery Bulletin 112(4) 
SOUTH AMERICA 
■ % •, 
Figure 1 
Map showing (A) Patos Lagoon and its estuarine zone (10.36 km 2 ) in Rio Grande, the southern- 
most state in Brazil; (B) the location of the pair of rocky jetties at the mouth of the lagoon (arrow) 
and, in the adjacent marine area, Carpinteiro Bank in the southwestern Atlantic. The lines along 
the coast denote the 10-, 15- and 20-m isobaths. The specimens of the dusky grouper (Epinephelus 
marginatus) sampled in this study were caught at the Carpinteiro Bank by small-scale fisheries 
from 2008 to 2011. 
able particularly to overfishing (Coleman et al., 2000; 
Sadovy et al., 2013). Quantifying the age and growth 
of dusky groupers is required, therefore, to support ad- 
equate conservation and management of this species at 
its southernmost region of occurrence. 
Previous investigations have provided initial infor- 
mation on the age structure of the dusky grouper in 
South America and also revealed the absence of repro- 
duction in a coastal population associated with littoral 
rocky jetties from extreme southern Brazil (Seyboth et 
al., 2011). Those authors adopted the classification de- 
veloped by Craig and Hastings (2007) that placed the 
dusky grouper in Mycteroperca. For our study, we fol- 
lowed the most recent classification (Craig et al., 2011), 
in which the species was retained in Epinephelus, given 
the absence of conclusive studies to change the genus. 
Another study conducted in this region revealed that 
the dusky grouper reproduces at offshore Carpinteiro 
Bank (Condini et al., 2014). 
In this study, we validated the timing of increment 
deposition in otoliths and examined the aging struc- 
ture and growth parameters of dusky grouper in an 
offshore habitat (Carpinteiro Bank, at depths of 15- 
25 m). Because we had access to the original data of 
Seyboth et al. (2011), we also aimed to test the hypoth- 
esis, previously reported by Seyboth et al. (2011), that 
offshore habitats (depths of 15-25 m) may constitute 
better habitats for growth and reproduction of dusky 
groupers than inshore habitats (depths <5 m). 
Material and methods 
Sampling, fish processing, and study area 
Dusky grouper samples examined in this study (n- 211) 
were identified according to Heemstra and Randall 
(1993). They were collected twice a month from land- 
ings in small-scale fisheries in Rio Grande, a port city 
in southern Brazil (Fig. 1), from 2008 to 2011. Fish 
were caught with hand lines, and their origin was eval- 
uated through interviews with owners of fishing boats. 
Only fish caught specifically at the Carpinteiro Bank 
were considered. In the laboratory, the total length 
(TL) in millimeters and weight (WT) in grams of each 
specimen were measured, and sex was identified by a 
macroscopic examination of the gonads following Ma- 
rino et al. (2001). Male and female gonadal differences 
are quite clear in macroscopic examination for this 
hermaphroditic grouper (Marino et al., 2001; Condini 
et al., 2014). The Carpinteiro Bank (32°16 S; 51°47 W) 
(Fig. 1) is a submersed reef, with depths ranging from 
15 to 25 m, formed by beach rocks and is superficially 
