Marine Biology

, Volume 155, Issue 1, pp 11–22 | Cite as

Population genetic structure of escolar (Lepidocybium flavobrunneum)

  • Kirsten S. Brendtro
  • Jan R. McDowell
  • John E. GravesEmail author
Original Paper


Escolar (Lepidocybium flavobrunneum) is a large, mesopelagic fish that inhabits tropical and temperate seas throughout the world, and is a common bycatch in pelagic longline fisheries that target tuna and swordfish. Few studies have explored the biology and natural history of escolar, and little is known regarding its population structure. To evaluate the genetic basis of population structure of escolar throughout their range, we surveyed genetic variation over an 806 base pair fragment of the mitochondrial control region. In total, 225 individuals from six geographically distant locations throughout the Atlantic (Gulf of Mexico, Brazil, South Africa) and Pacific (Ecuador, Hawaii, Australia) were analyzed. A neighbor-joining tree of haplotypes based on maximum likelihood distances revealed two highly divergent clades (δ = 4.85%) that were predominantly restricted to the Atlantic and Indo-Pacific ocean basins. All Atlantic clade individuals occurred in the Atlantic Ocean and all but four Pacific clade individuals were found in the Pacific Ocean. The four Atlantic escolar with Pacific clade haplotypes were found in the South Africa collection. The nuclear ITS-1 gene region of these four individuals was subsequently analyzed and compared to the ITS-1 gene region of four individuals from the South Africa collection with Atlantic clade haplotypes as well as four representative individuals each from the Atlantic and Pacific collections. The four South Africa escolar with Pacific mitochondrial control region haplotypes all had ITS-1 gene region sequences that clustered with the Pacific escolar, suggesting that they were recent migrants from the Indo-Pacific. Due to the high divergence and geographic separation of the Atlantic and Pacific clades, as well as reported morphological differences between Atlantic and Indo-Pacific specimens, consideration of the Atlantic and Indo-Pacific populations as separate species or subspecies may be warranted, though further study is necessary.


Bluefin Tuna Mitochondrial Control Region Bigeye Tuna Blue Marlin Control Region Haplotype 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.



We would like to thank D. Kerstetter, A. Amorim, P. Jaimez Diaz, C. Smith, H. Espindola, K. Rowling, J. Pepperell, B. Taylor, K. Hoshino, K. Busscher and the NMFS Longline Observers Program, and M. Musyl and the crew of the R/V Oscar Elton Sette for assistance with tissue sample collection. Bruce Collette provided a critical review of the manuscript. VIMS Contribution Number 2941. Funded by NMFS Highly Migratory Species Division. All experiments of this study comply with current laws of the United States of America.


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Copyright information

© Springer-Verlag 2008

Authors and Affiliations

  • Kirsten S. Brendtro
    • 1
  • Jan R. McDowell
    • 1
  • John E. Graves
    • 1
    Email author
  1. 1.School of Marine Science, Virginia Institute of Marine ScienceCollege of William and MaryGloucester PointUSA

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