Weak genetic structure indicates strong dispersal limits: A tale of two coral reef fish

John F.H. Purcell, Robert K. Cowen, Colin R. Hughes, Dean A. Williams

Research output: Contribution to journalArticlepeer-review

110 Scopus citations


The extent of dispersal by pelagic larvae in marine environments, including coral reefs, is central for understanding local population dynamics and designing sustainable marine reserves. We present here the first example of a clear stepping-stone genetic structure throughout the Caribbean basin for a common coral reef species, the French grunt (Haemulon flavolineatum). Analysis of microsatellite DNA markers indicated that French grunt population structure may be characterized by overlapping populations throughout the Caribbean, influenced by independent population dynamics but with no fixed geographical boundaries. In addition, different spatial genetic patterns were found in different oceanographic regions. A second species, the bluehead wrasse (Thalassoma bifasciatum), has a much longer pelagic larval duration than French grunts and showed no explicit spatial pattern of genetic variation. This finding is concordant with the hypothesis of a positive relationship between larval dispersal and duration in the plankton. While the magnitude of the genetic signal of population structure in French grunts was very low (FST ≈ 0.003), the pattern of isolation-by-distance throughout the Caribbean indicated considerable population structure with important ecological and conservation significance.

Original languageEnglish (US)
Pages (from-to)1483-1490
Number of pages8
JournalProceedings of the Royal Society B: Biological Sciences
Issue number1593
StatePublished - Jun 22 2006
Externally publishedYes


  • Coral reef fish dispersal
  • Genetic population structure
  • Haemulon flavolineatum
  • Marine reserves
  • Microsatellites
  • Thalassoma bifasciatum

ASJC Scopus subject areas

  • Agricultural and Biological Sciences(all)
  • Agricultural and Biological Sciences (miscellaneous)


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