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Stretched to breaking point; when does short pelagic larval duration fail to connect conspecific populations? An example from Kuhlia rupestris, an Indo-Pacific diadromous fish.

TitreStretched to breaking point; when does short pelagic larval duration fail to connect conspecific populations? An example from Kuhlia rupestris, an Indo-Pacific diadromous fish.
Type de publicationJournal Article
Year of Publication2013
AuteursFeutry, P, Vergnes, A, Broderick, D, Lambourdière, J, Keith, P, Ovenden, JR
JournalMolecular Ecology
Volume22
Pagination1518-1530
Mots-cléscryptic species, dispersion, microsatellites, mitochondrial markers, ocean-current modelling, tropical islands
Résumé

Freshwater species on tropical islands face localized extinction and the loss of genetic
diversity. Their habitats can be ephemeral due to variability in freshwater run-off and
erosion. Even worse, anthropogenic effects on these ecosystems are intense. Most of
these species are amphidromous or catadromous (i.e. their life cycle includes a marine
larval phase), which buffers them against many of these effects. A long pelagic larval
duration (PLD) was thought to be critical to ensure the colonization and persistence in
tropical islands, but recent findings indicated that several species with short PLDs are
successful in those ecosystems. To test the potential of a short PLD in maintaining
genetic connectivity and forestalling extirpation, we studied Kuhlia rupestris, a catadromous
fish species with an extensive distribution in the western Pacific and Indian
Oceans. Using a combination of molecular genetic markers (13 microsatellite loci and
two gene regions from mtDNA) and modelling of larval dispersal, we show that
a short PLD constrains genetic connectivity over a wide geographical range. Molecular
markers showed that the short PLD did not prevent genetic divergence through evolutionary
time and speciation has occurred or is occurring. Modelling of larvae dispersal
suggested limited recent connectivity between genetically homogeneous populations
across the Coral Sea. However, a short PLD can maintain connectivity on a subocean
basin scale. Conservation and management of tropical diadromous species needs to
take into account that population connectivity may be more limited than previously
suspected in those species.
Keywords: cryptic species, dispersion