Syc and Szedlmayer: A comparison of size and age of Lutjanus campechanus with the age of artificial reefs in the Gulf of Mexico 
459 
available biomass of reef species. The artificial reef 
system in the northern Gulf of Mexico has been stud- 
ied extensively — many studies focusing on various 
life history aspects of red snapper as a means to help 
resolve the question of whether or not artificial reefs 
enhance production. 
The first group of studies involved diet analyses of the 
stomach contents of red snapper. If enhanced production 
is occurring, then red snapper diets should contain reef 
prey species; but, if only attraction is occurring, red 
snapper should be feeding on prey species not found 
on reefs. Evidence supporting both scenarios has been 
reported. For example, some studies reported that most 
red snapper prey items were species associated with the 
water column and sand-mud habitat (McCawley et al., 
2006; Wells et al., 2008b). In contrast, other studies 
showed significant feeding on reef species (Ouzts and 
Szedlmayer, 2003; Szedlmayer and Lee, 2004; Redman 
and Szedlmayer, 2009). 
Site fidelity of red snapper to artificial reefs also has 
been used to examine the question of enhanced pro- 
duction on artificial reefs. Again, 2 differing scenarios 
have been reported. Low residency and lack of site 
fidelity support the attraction hypothesis (Patterson 
et al., 2001b, Peabody, 2004), and long-term (>1020 d) 
residency on artificial reefs and high site fidelity sup- 
port the production hypothesis (Szedlmayer and Shipp, 
1994; Szedlmayer, 1997; Szedlmayer and Schroepfer, 
2005; Schroepfer and Szedlmayer, 2006; Topping and 
Szedlmayer, 2011a; 2011b). 
These previous studies indicate that attraction of red 
snapper to artificial reefs is occurring, but the extent 
to which artificial reefs also enhance production is an 
open question. Although it is relatively easy to provide 
evidence for attraction, it is not as easy to find evidence 
for production. Therefore, we contend that it still is not 
clear whether artificial reefs produce new red snapper 
biomass or whether they only attract fish of this species 
and make them more vulnerable to fishing mortality. 
A new approach to this long-standing question would 
be to compare the age of resident fish with the age of 
the artificial reef where they occur. If enhanced produc- 
tion is occurring, new reefs should attract new recruits, 
and these recruits likely would stay and grow as their 
reef ages, becoming the dominate age class and would 
possibly exclude new recruits from the reef habitat. 
In this case, the age of fish resident at a reef should 
be positively correlated with the age of the reef. In 
contrast, if artificial reefs simply attract red snapper, 
reef age should not be correlated with fish age but, 
rather, should be related to the proximity of red snap- 
per on other reefs and red snapper movement patterns. 
For our study, artificial reefs were deployed in 2006, 
2009, and 2010, and the size and age of red snapper 
were compared among these 3 reef ages to help clarify 
whether artificial reefs may be enhancing red snap- 
per production. The positions of these reefs were not 
released to the public to reduce the potential effects 
of variation in fishing mortality on age distributions 
of red snapper. 
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Figure 1 
Map of sampling locations in our study of red snapper 
( Lutjanus campechanus ) on artificial reefs in the north- 
ern Gulf of Mexico in 2010. Gray circles=reefs deployed 
in 2006; open circles = reefs deployed in 2009; and black 
circles=reefs deployed in 2010. Dotted lines indicate depth 
contours at 5-m intervals. 
Materials and methods 
Sample sites 
The area of our study was located 20-30 km south of 
Mobile Bay, Alabama (Fig. 1). This area has more than 
15,000 artificial reefs and a few natural, rocky reefs 
(Minton and Heath, 1998). For our study, artificial 
reefs (4. 4x1. 3x1. 2 m, metal cages) were deployed in 
April 2006 (/z =20, which became 4-year-old reefs in our 
study), April 2009 (n = 10, which became 1-year-old reefs 
in our study), and January 2010 (n = 10, which became 
0.5-year-old reefs in our study). Reef locations were not 
published to limit potential fishing mortality. All the 
reefs we studied were located 1. 3-1.7 km from other 
reefs deployed in this study. These reefs were deployed 
at the following depths: 27-32 m in 2006, 18-24 m in 
2009, and 23-31 m in 2010. 
All reefs were sampled from April to November 2010. 
The reefs deployed in 2010 were not sampled until at 
least 5 months after their deployment to allow adequate 
time for the immigration of red snapper (Mudrak and 
