NOTE Richardson and Gold: Mitochondrial DNA diversity in and population structure of Epmephelus mono 
177 
Tabie 2 
Comparison of estimates of intrapopulational mtDNA di- 
versity in various species of marine fishes. 
Species 
Number of 
individuals 
surveyed 
Number of 
mtDNA 
haplotypes 
Nucleotide 
sequence 
diversity (%) 
Bluefish 7 
372 
40 
1.23 
Atlantic herring 2 
69 
26 
1.09 
Gulf Menhaden 3 
16 
16 
0.99 
Red drum 4 
693 
99 
0.88 
Spanish sardine 5 
73 
24 
0.52 
Red snapper 4 
421 
68 
0.50 
Black drum 4 
300 
37 
0.48 
Greater 
amberjack 6 
59 
23 
0.34 
Spotted seatrout 7 
384 
73 
0.31 
Orange roughy 3 
244 
22 
0.13 
Weakfish 9 
370 
11 
0.13 
Red grouper 
105 /0 
16 
0.05 i; 
Atlantic black 
sea bass 2 
19 
3 
0.03 
Gulf black sea bass 2 9 
2 
0.03 
I Graves et al., 1992a. 
2 Kornfield and Bogdanowicz, 1987. 
3 Bowen and Avise, 1990. 
4 Gold et al., 1994. 
5 Tringali and Wilson, 1993. 
6 Richardson and Gold, 1993. 
7 Gold, J. R. 1995. Dep. of Wildlife and Fisheries Sciences, Texas 
A&M Univ., College Station, TX 77843-2258. Unpubl. data. 
8 Smolenski et al., 1993. 
9 Graves et al., 1992b. 
;o Number of individuals includes 5 additional specimens from the 
Dry Tortugas surveyed by Richardson and Gold (1993). 
II Value obtained by using 28 restriction enzymes surveyed in 
Richardson and Gold (1993). Value obtained from the ten poly- 
morphic restriction enzymes surveyed here is 0.15. 
Beaumariage 1 ). Presumably, this migration corre- 
sponds to the onset of sexual maturity. Other tag- 
ging data (Moe, 1966) suggest that adult red grou- 
per may move as much as 18 to 50 miles over a pe- 
riod of time from several months to a year. Finally, 
on the basis of data from other species of Epinephelus 
(Mito et al., 1967), the pelagic larval stage in E. morio 
is presumed to last 30-40 days, during which larvae 
are dispersed by ocean currents along a great por- 
tion of the Florida shelf (Moe, 1969). However, de- 
spite the evidence suggesting that individual red 
grouper could move considerable distances, consis- 
tent patterns of migration in red grouper are not re- 
1 Beaumariage, D. S. 1969. Returns from the 1965 Schlitz tag- 
ging program including a cumulative analysis of previous re- 
sults. Fla. Dept. Nat. Resources, Mar. Res. Lab., Tech. Ser. 
No. 59:1-38. Div. of Mar. Resources, Dep. of Environmental 
Protection, Florida Mar. Res. Inst., 100 Eighth Ave. SE, St. Pe- 
tersburg, FL 33701. 
ported, and it is generally presumed that adult red 
grouper do not undergo large-scale movements offshore. 
Gene flow between the west Florida shelf and the 
Campeche Banks via migration of adults would have 
to occur either 1 ) along the north-central and west- 
ern Gulf or 2) across the Florida Straights. Rivas 
( 1970) noted circumstantial evidence suggesting that 
there may be seasonal migration of red grouper be- 
tween the northern and southern Gulf, most prob- 
ably via a western route. Red grouper, however, are 
rarely taken in the Gulf west of the Mobile Basin 
(Springer and Bullis, 1956), and virtually no land- 
ings of red grouper occur along most of the Texas 
coast (Osburn 2 ; Campbell 3 ). The apparent paucity of 
red grouper in the northwestern Gulf may reflect 
either the absence of suitable habitat along the 
Texas-Louisiana shelf or be a result of some other 
extrinsic barrier (McEachran 4 ). These observations 
suggest that movement of adult red grouper through 
the western Gulf is unlikely, if it occurs at all. With 
respect to movement across the Florida Straights, 
Rivas ( 1970) considered it unlikely that red grouper, 
a bottom dwelling fish, would cross great depths. The 
Florida Straights are characterized by 100 to 2,000 
fathom depths that separate the Campeche Banks 
from the west Florida shelf (Rezak et al., 1985). This 
range also suggests limited movement, if any, of red 
grouper from west Florida to the Campeche Banks. 
Alternatively, present-day gene flow among red 
grouper could occur through dispersal of larvae by 
ocean currents. Shulman and Bermingham (1995) 
recently examined variation in mtDNA data among 
eight species of reef-associated fishes and searched 
for correlations between gene flow and egg type (pe- 
lagic and nonpelagic) and length of planktonic (usu- 
ally larval) life, two life history traits which could 
potentialy affect dispersal capability. Although sur- 
face currents that might explain observed genetic 
homogeneity in five of the species were identified, 
neither egg type nor length of larval stage appeared 
to be an adequate predictor of geographic structure 
in reef associated fishes (Shulman and Bermingham, 
1995). Therefore, even though red grouper may have 
2 Osburn, H. R. 1988. Trends in finfish landings by sport-boat 
fishermen in Texas marine waters, May 1974-May 1987. Texas 
Parks Wildl. Dep., Manag. Data Ser., no. 150, Austin, TX. Fish- 
eries and Wildlife Div., Coastal Fisheries Branch, Texas Parks 
and Wildlife Dep., 4200 Smith School Road, Austin, TX 78744. 
3 Campbell, R. P. 1993. Trends in Texas commercial fishery 
landings, 1972-1992. Texas Parks Wildl. Dep., Manag. Data 
Ser., no. 106, Austin, TX. Fisheries and Wildlife Div., Coastal 
Fisheries Branch, Texas Parks and Wildlife Dep., 4200 Smith 
School Road, Austin, TX 78744. 
4 McEachran, J. D. 1995. Dep. of Wildlife and Fisheries Sci- 
ences, Texas A&M Univ., College Station, TX 77843-2258. Per- 
sonal commun. 
