462 
Fishery Bulletin 1 10(4) 
Figure 2 
Length frequency of red snapper ( Lutjanus campechanus ) caught in our 
study on artificial reefs in the northern Gulf of Mexico in 2010, shown 
by year that reef was deployed, separated into 100-mm standard-length 
(SL) size classes (e.g., 100 = 100-199 mm). 
Table 2 
Mean (±SD) standard length (SL), weight, and age of red snapper ( Lutjanus campechanus) caught during our study on artificial 
reefs deployed in 2006, 2009, and 2010 in the northern Gulf of Mexico. Superscript letters are used to indicate significant dif- 
ferences (P <0.05). Included for each reef year are the total number of red snapper caught by hook-and-line and trap, mean diver 
count, and mean density estimate. Estimates of mean density per reef combine diver counts and catch of hook-and-line and trap. 
Reef year 
SL (mm) 
Weight (kg) 
Age (yr) 
Hook and line 
Trap 
Diver count 
Density 
2006 
373.3 ±107.8 a 
1.88 ±1.39 a 
3.54 ±1.24° 
20.2 ±8.8 
12.4 ±11.3 
115.5 ±87.8 
148.7 ±92.5 
2009 
250.2 ±114.7 b 
0.85 ±1.46 b 
1.98 ±1.70 6 
5.3 ±6.1 
22.5 ±18.4 
54.0 ±35.8 
81.8 ±41.2 
2010 
222.3 ±78.0 c 
0.48 ±0.71 c 
1.72 ±1.00° 
2.3 ±4.6 
15.6 ±11.6 
36.0 ±31.7 
55.6 ±45.6 
and new (2009 and 2010) reefs (ANCOVA, F 3 101g =2.98, 
P=0.085, power>0.99). 
The mean depth (30 m) of the 2006 reefs were sig- 
nificantly greater than the mean depth (20 m) of the 
2009 reefs (Gtest, £ 26 =16.32, P<0.0001). Because of this 
depth difference, red snapper also were compared 
among the 2006 and 2010 reefs (n = 8) with the same 
depth (30 m). These comparisons also showed signifi- 
cantly larger and older red snapper on the 2006 reefs 
(mean ±SD = 368.7 ±5.0 mm SL, 1821 ±1326 g, 3.60 
±1.20 years) compared to 2010 reefs (236.2 ±85.2 mm 
SL, 578 ±814 g, 1.91 ±1.10 years; Ptest, P<0.0001). 
Comparisons of our estimates of red snapper abun- 
dance and age on artificial reefs by proximity (<1.7 
km) to other known reefs not sampled in our study 
failed to detect a significant effect. These other nearby 
reefs have published locations because they are part of 
Alabama’s artificial reef program and were deployed 
