Carson et al.: Population structure, long-term connectivity, and effective size of Lutjanus analis 
417 
(Matos-Caraballo et al., 2004), and fillets often sell 
for as much as US $12 per pound in Miami seafood 
markets (Watanabe, 2001). Landings of mutton snap- 
per, however, have declined over the past decade in 
Puerto Rico (Matos-Caraballo et al., 2004; Cummings, 
2007a, 2007b) and in southern Florida. In the lat- 
ter fishery, commercial landings between the years 
2006 and 2009 dropped from 127.0 to 53.6 metric tons 
(http://www.st.nmfs.noaa.gov/stl/commercial/landings/ 
annual_landings.html, accessed July 2011). Although 
mutton snapper are not considered overfished in U.S. 
waters of the western Atlantic Ocean and Caribbean 
Sea (Federal Register, 2005), concern regarding the 
condition of the fishery has prompted both seasonal 
and permanent closures off southwest Florida, Puerto 
Rico, and the U.S. Virgin Islands (http://www.edf.org/ 
article. cfm?contentid= 443; http://sero.nmfs.noaa.gov/ 
sf/ClosedAreaCoordinates.htm, accessed March 2011). 
Finally, aggregate spawning of mutton snapper is well 
documented (Claro, 1981; Domeier et al.,1996), with 
known aggregations occurring at Riley’s Hump in the 
Dry Tortugas National Park, Florida (Domeier, 2004; 
Burton et al., 2006), Gladden Spit, Belize (Graham 
et al., 2008), numerous sites along the coast of Cuba 
(Claro and Lindeman, 2003), Turks and Caicos (Muel- 
ler, 1994; Doemeier et al., 1997), off the southwest 
coast of St. Croix in the U.S. Virgin Islands, (SEDAR, 
2007), and at La Parguera shelf along the southwest 
coast of Puerto Rico (Esteves, 2005). Other, less well- 
documented aggregations occur in the Cayman Islands 
and the Bahamas (Heyman 1 ). 
In a recent study by Shulzitski et al. (2009), varia- 
tion at eight nuclear-encoded microsatellites was used 
to investigate population structure in mutton snapper 
sampled from localities off the Florida Keys, two locali- 
ties in the western Caribbean Sea (Belize and Hondu- 
ras), and the west coast of Puerto Rico. No evidence of 
genetic heterogeneity was found, leading these authors 
to suggest that larval dispersal or long-distance migra- 
tion of adults maintained genetic homogeneity over such 
a broad geographic scale. However, simulation studies 
based on prevailing currents in the Caribbean Sea have 
indicated that larval transport of reef-associated species 
in most areas in the region is limited, with average dis- 
tances of 145 and 212 km for one- and two-month peri- 
ods of larval dispersal, respectively (Roberts, 1997), and 
with ecologically relevant larval dispersal distances in 
the 10-100 km range (Cowen et al., 2000, 2006). In ad- 
dition, empirical studies in the region have shown that 
species with the capacity for long-range larval dispersal 
often exhibit high levels of larval retention (Taylor and 
Hellberg, 2003) and that the degree of dispersal can 
differ substantially between windward (high dispersal) 
and leeward (low dispersal) sides of islands (Swearer et 
al., 1999). Finally, the few data that exist (Beaumar- 
iage, 1969; Mueller, 1995; Farmer, 2009) indicate that 
1 Heyman, W. D. 2010. Personal commun. Department of 
Geography, Texas A&M University, College Station, Texas 
77843-3148. 
movement of adult mutton snapper is generally limited 
to only a few kilometers. 
The possibility of limited larval transport and long- 
distance adult movement among mutton snapper in 
the region may indicate that the genetic homogeneity 
observed by Shulzitski et al. (2009) at markers (mi- 
crosatellites) presumed to be selectively neutral may 
obscure other differences that impact local population 
sustainability. The goal of the present study was to 
examine this possibility further by using genetic data 
to assess both long-term connectivity (migration) and 
effective population size (N e ) among the sampled locali- 
ties. Populations with homogeneous allele frequencies at 
selectively neutral loci do not necessarily have the same 
effective sizes (Saillant and Gold, 2006) and differences 
in N e could signal populations with reduced sustain- 
ability and capability to respond to environmental pres- 
sures such as over-exploitation or habitat degradation 
(Frankham, 1995). 
Materials and methods 
A total of 498 mutton snapper were sampled between 
2007 and 2009 from four localities in the northern Carib- 
bean Sea and one locality in the Florida Keys (Fig. 1). 
The locality in the Florida Keys is near a now annually 
protected mutton snapper spawning aggregation in the 
Dry Tortugas; the locality off the west coast of Puerto 
Rico is near several marine protected areas (MPAs) 
and a mutton snapper spawning aggregation off the 
southwest coast; the locality off the south coast of St. 
Thomas is near several MPAs; and the locality off the 
southwest coast of St. Croix is a seasonally protected 
mutton snapper spawning aggregation area. Samples 
from the Florida Keys (FK) were obtained from local 
fishermen or fish houses in or near Marathon, Florida. 
Samples from the west coast of Puerto Rico (PR-west) 
were procured from fish houses in or near Mayaguez, 
whereas samples from the east coast of Puerto Rico (PR- 
east) were obtained at fish houses in or near Fajardo. 
Samples from St. Croix (SC) were obtained as part of 
an ongoing project of the Caribbean Fishery Manage- 
ment Council (Kojis and Quinn 2 ), and samples from St. 
Thomas (ST) came from the Gustave Quetel Fish House 
in Frenchtown (Charlotte Amalie) or local fishermen. 
Sample sizes were as follows: FK (118), PR-east (96), 
PR-west (94), ST (97), and SC (93). Except for samples 
from St. Croix (SC), small pieces (4-5 mm 3 ) of caudal fin 
were removed from each fish and fixed in 95% ethanol. 
Samples from St. Croix primarily were internal organs 
fixed in DMSO storage buffer (Seutin et al., 1991). DNA 
2 Kojis, B. L., and N. J. Quinn. 2011. Validation of a spawn- 
ing aggregation of mutton snapper and characterization of 
the benthic habitats and fish in the mutton snapper sea- 
sonal closed area, St. Croix, U.S. Virgin Islands. [Available 
at http://www.caribbeanfmc.com/pdfs%202011/Mutton%20 
Snapper%20Report%20for%20CFMC%20-%2014%20Feb%20 
11%20, Final.pdf, accessed July 2011.] 
