674 
Fishery Bulletin 99(4) 
Table t 
Allele frequencies, sample sizes (n), percentage of polymorphic loci per population, and mean heterozygosity per locus. LM = 
Laguna Madre, Texas; MAT = Matagorda Bay, Texas; GAL = Galveston Bay, Texas; SAB = Sabine Lake, Texas; MIS = off Biloxi, 
Mississippi; ALA = Mobile Bay, Alabama; STA = off St. Augustine, Florida; NC = Core Sound, North Carolina. 
Locus 
Allele 
LM 
MAT 
GAL 
SAB 
MIS 
ALA 
STA 
NC 
ESTD-1 * I ’ 3 
*1 
0.972 
0.918 
0.889 
0.917 
0.885 
1.000 
1.000 
0.959 
* 2 
0.028 
0.082 
0.111 
0.083 
0.115 
0.000 
0.000 
0.027 
*3 
0.000 
0.000 
0.000 
0.000 
0.000 
0.000 
0.000 
0.014 
n 
54 
61 
36 
24 
13 
21 
20 
37 
ESTD-2* ] - 3 
* i 
0.009 
0.000 
0.014 
0.000 
0.000 
0.000 
0.000 
0.054 
*2 
0.981 
1.000 
0.917 
1.000 
1.000 
1.000 
1.000 
0.946 
*, 3 
0.009 
0.000 
0.069 
0.000 
0.000 
0.000 
0.000 
0.000 
n 
54 
61 
36 
24 
13 
21 
20 
37 
PEPB-2 * l - 3 
*i 
0.074 
0.016 
0.014 
0.000 
0.038 
0.024 
0.025 
0.000 
*2 
0.926 
0.984 
0.986 
0.958 
0.962 
0.976 
0.975 
1.000 
* 3 
0.000 
0.000 
0.000 
0.042 
0.000 
0.000 
0.000 
0.000 
n 
54 
61 
36 
24 
13 
21 
20 
37 
G3PDH* 23 
* i 
0.120 
0.098 
0.014 
0.000 
0.000 
0.000 
0.000 
0.000 
*2 
0.778 
0.779 
0.972 
0.848 
0.808 
0.833 
0.875 
0.946 
*3 
0.102 
0.123 
0.014 
0.152 
0.192 
0.167 
0.125 
0.054 
n 
54 
61 
36 
23 
13 
21 
20 
37 
GPI-A* 1 - 3 
* i 
1.000 
0.992 
1.000 
1.000 
0.962 
0.929 
0.975 
1.000 
*2 
0.000 
0.008 
0.000 
0.000 
0.038 
0.071 
0.025 
0.000 
n 
54 
61 
36 
24 
13 
21 
20 
36 
GPI-B* lA 
■'7 
0.000 
0.000 
0.000 
0.125 
0.000 
0.000 
0.000 
0.000 
*2 
1.000 
1.000 
0.986 
0.875 
1.000 
1.000 
1.000 
1.000 
*3 
0.000 
0.000 
0.014 
0.000 
0.000 
0.000 
0.000 
0.000 
n 
54 
61 
36 
24 
13 
21 
20 
37 
PGM * 1A 
* i 
0.009 
0.008 
0.086 
0.000 
0.000 
0.000 
0.000 
0.000 
* 2 
0.991 
0.992 
0.829 
1.000 
1.000 
1.000 
1.000 
1.000 
*3 
0.000 
0.000 
0.086 
0.000 
0.000 
0.000 
0.000 
0.000 
n 
54 
61 
35 
24 
13 
21 
20 
37 
G6PDH-1* 13 
*i 
0.991 
1.000 
1.000 
1.000 
1.000 
1.000 
1.000 
1.000 
* 2 
0.009 
0.000 
0.000 
0.000 
0.000 
0.000 
0.000 
0.000 
n 
54 
61 
36 
24 
13 
21 
20 
37 
G6PDH-2* I - 3 
*i 
0.000 
0.000 
0.114 
0.000 
0.000 
0.095 
0.025 
0.000 
*2 
0.639 
0.648 
0.871 
0.896 
0.962 
0.881 
0.975 
1.000 
■ : 3 
0.361 
0.352 
0.014 
0.104 
0.038 
0.024 
0.000 
0.000 
n 
36 
61 
35 
24 
13 
21 
20 
37 
% polymorphic loci 
10.29 
8.82 
10.29 
7.35 
7.35 
5.88 
5.88 
4.41 
Heterozygosity 
0.10 
0.12 
0.09 
0.08 
0.08 
0.09 
0.03 
0.03 
Direct count (SE) 
(0.05) 
(0.06) 
(0.04) 
(0.03) 
(0.03) 
(0.04) 
(0.02) 
(0.02) 
' Buffer = TVB (Tris-borate-EDTA, pH 8.0). 
- Buffer = borate 9. 
3 Tissue = muscle. 
3 Tissue = liver. 
ern Gulf and the Atlantic coast approached significance 
(P=0.07). The results of chi-square tests for population dif- 
ferentiation (Table 4) allowed a pairwise examination of 
differences among the eight sampling sites. Eastern sam- 
ple sites were not significantly different (P>0.01) from 
their nearest geographic neighbors. Western sites, from 
Sabine Lake to the lower Laguna Madre, were statis- 
tically different from at least one neighbor, suggesting 
more pronounced genetic differentiation in the western 
Gulf of Mexico. Among Gull' of Mexico samples, no sta- 
