322 
Abstract— Twenty homologous mi- 
crosatellite markers, or simple se- 
quence repeats (SSRs), were devel- 
oped for blackfin tuna (Thunnus at- 
lanticus) through the use of a direct 
Seq-to-SSR approach. The number 
of alleles per locus ranged between 
5 and 26, and the expected hetero- 
zygosity ranged between 0.640 and 
0.969. Three loci displayed signifi- 
cant departure from Hardy-Wein- 
berg equilibrium expectations, likely 
reflecting occurrence of null alleles. 
Another locus showed consecutive 
alleles that differed by one base pair 
only. Consequently, this locus may be 
prone to elevated rates of scoring er- 
rors. The remaining 16 loci will be 
valuable for studies in conservation 
genetics of blackfin tuna. 
Development and characterization of 
microsatellite markers for blackfin tuna 
( Thunnus atlanticus ) with the use of 
lllumina paired-end sequencing 
Luca Antoni 1 
Patricia L. tuque 1 
Kaylie Naghshpour 1 
Lionel Reynal 2 
Eric A. Saillant (contact author ) 1 
Email address for contact author: eric.saillant@usm.edu 
1 Gulf Coast Research Laboratory 
The University of Southern Mississippi 
703 East Beach Drive 
Ocean Springs, Mississippi 39564 
2 Institut Francais de Recherche pour (Exploitation de la Mer (IFREMER) 
Unite Biodiversite et Environnement de la Martinique 
79 Route de Pointe-Fort 
97231 Le Robert 
Martinique, France 
Manuscript submitted 7 January 2014. 
Manuscript accepted 25 August 2014. 
Fish. Bull. 112:322-325 (2014). 
doi:10.7755/FB.112.4.8 
The views and opinions expressed or 
implied in this article are those of the 
author (or authors) and do not necessarily 
reflect the position of the National 
Marine Fisheries Service, NOAA. 
The blackfin tuna (Thunnus atlanti- 
cus) is a small tuna widely distribut- 
ed in tropical and subtropical waters 
of the western Atlantic Ocean from 
the mid-Atlantic region of the East 
Coast of the United States south to 
northern Brazil (Collette and Nauen, 
1983). Although this species is ex- 
ploited by fisheries in several coun- 
tries, management of this resource 
in the United States and abroad is 
almost inexistent and, in particu- 
lar, it is not known to date whether 
multiple stocks of this species oc- 
cur within its recorded distribution 
range (Mathieu et al., 2013). 
Tagging studies conducted in the 
island nations of St. Vincent and the 
Grenadines and Bermuda have indi- 
cated that blackfin tuna exhibit some 
degree of site fidelity for a significant 
proportion of tagged fish that have 
been recaptured in close proximity 
of their tagging location, sometimes 
over multiple years (Luckhurst et 
al., 2001; Singh-Renton and Renton, 
2007). However, long distance move- 
ments also were reported for some of 
the individuals tagged in the study of 
Singh-Renton and Renton (2007). In 
such a situation, the analysis of ge- 
netic variation at molecular markers 
is expected to provide valuable in- 
formation on the structure of stocks 
to develop sustainable management 
of fisheries (Carvalho and Hauser, 
1994). Microsatellites are the most 
widely used markers for genetic 
studies of exploited fishes; however 
to date homologous markers for the 
blackfin tuna are not available. 
The objective of this work was to 
develop homologous microsatellite 
markers, or simple sequence repeats 
(SSRs), for studies in conservation 
genetics of this species. The appli- 
cation of next-generation sequenc- 
ing technologies greatly enhances 
microsatellite discovery through di- 
rect screening of short sequences of 
genomic DNA, hereafter reads , for 
repeat arrays without the need for 
cost-prohibitive steps, such as cloning 
of genomic libraries and screening of 
individual clones through Sanger se- 
quencing. The Seq-to-SSR method of 
Castoe et al. (2012) is based on direct 
screening of unassembled sequencing 
reads, an approach that further in- 
creases the cost effectiveness of the 
