Merten et al.: Genetic structure and dispersal capabilities of Coryphaena hippurus in the western Atlantic 
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Figure 2 
Statistical parsimony network for dolphinfish ( Coryphaena hippurus ) based on mitochondrial nicotinamide adenine di- 
nucleotide (NADH) dehydrogenase subunit 1 (ND1) sequences. The size of circles is proportional to the number of shared 
haplotypes represented as pie charts. The small white circles on the connecting lines indicate the number of mutations 
among haplotypes and internal nodes. The color of a section in pie charts indicates a region: northeastern Caribbean Sea 
(NEC); southeastern United States (USSE); eastern Caribbean Sea (EC); central North Atlantic (CNA). The circles next to 
the legend indicate the proportionality of the number of haplotypes to the size of the circles (1-10, 27, and 38). 
northern and southern coasts were compared over 4 
consecutive years (2010-2013). All samples were then 
compared with samples collected from the southeastern 
United States during 2012, from the eastern Caribbean 
Sea during 1998 and 2014, and from the central North 
Atlantic during 1998. Lastly, a statistical parsimony 
network was generated for all haplotypes with TCS, 
vers. 1.2.1 (Clement et al., 2000) and redrawn in Adobe 
Photoshop CS5. 
Results 
From 324 specimens of dolphinfish collected primarily 
around the western central Atlantic, 199 haplotypes of 
a 1288-bp fragment containing ND1 and its adjacent 
tRNAs were resolved (Fig. 1). The haplotype network 
was characterized by a high number of singletons (Fig. 
2). The most numerically dominant haplotype (N=38) 
was found in all sampling locations and mean h was 
high (0.9699), ranging from 0.9623 in the eastern Ca- 
ribbean Sea to 0.9768 in the northeastern Caribbean 
Sea (Table 1). 
Population structure 
Significant overall population differentiation 
(<J>St-0-009, P=0.023) was revealed through AMOVA 
of all samples, but AMOVA did not reveal differentia- 
tion among areas within regions (i.e. , between north- 
ern and southern Puerto Rico within the northeastern 
Caribbean Sea, among North Carolina, South Carolina, 
and Florida within the southeastern United States, 
or among Barbados, Dominica, and Trinidad and To- 
bago within the eastern Caribbean Sea) (cpgc=0.014, 
P=0.059) and among regions (i.e., northeastern Carib- 
bean Sea versus southeastern United States versus 
eastern Caribbean Sea) (<f , cT= -0.005, P=0.301) (Table 
2). Pairwise comparisons among regions failed to re- 
veal significant differences. In addition, pairwise com- 
parisons between the northern and southern coasts of 
Puerto Rico did not reveal significant differences ( ®st= 
-0.002, P=0.640). 
Population expansion 
For all regions, Fu’s Pg showed significant (P<0.05) 
negative departures from neutrality and supported the 
spatial-population-expansion model (Table 1, Fig. 3). In 
addition, nonsignificant raggedness values supported 
the spatial-population-expansion model (Table 1). Esti- 
mates of x (time in generations) were similar among all 
regions and compatible with the timing of recent popu- 
lation expansion beginning around 80,500 years ago 
(Table 3). For the southeastern United States, north- 
eastern Caribbean Sea, and the Azores Islands, there 
