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

• Published in: Proceedings of the Royal Society. B, Biological sciences Vol. 273; no. 1593; pp. 1483 - 1490
• Main Authors: Purcell, John F.H, Cowen, Robert K, Hughes, Colin R, Williams, Dean A
• Format: Journal Article
• Language: English
• Published: London The Royal Society 22-06-2006
• Subjects: Animal Migration; Animals; Caribbean Region; Coral Reef Fish Dispersal; Coral reefs; Evolutionary genetics; Fish larvae; Genetic loci; Genetic Population Structure; Genetic variation; Genotype; Geography; Haemulon flavolineatum; Larva - genetics; Larva - physiology; Larvae; Marine; Marine fishes; Marine Reserves; Microsatellite Repeats; Microsatellites; Oceans and Seas; Perciformes - genetics; Perciformes - physiology; Polymorphism, Genetic; Population Dynamics; Population genetics; Population structure; Sequence Analysis, DNA; Thalassoma bifasciatum; Caribbean Region; ASW, Caribbean Sea
• ISSN: 0962-8452; 1471-2954
• DOI: 10.1098/rspb.2006.3470

Haemulon flavolineatum
), 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 (
≈0.003), the pattern of isolation-by-distance throughout the Caribbean indicated considerable population structure with important
ecological and conservation significance.
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 (
). 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