A lack of spatial genetic structure of Gymnothorax chilospilus (moray eel) suggests peculiar population functioning
Résumé
Moray eels form a speciose lineage that belongs to Elopomorpha, a super-order with a worldwide distribution.
As is the case for many anguilliform fish, moray eels are characterized by distinctive life history traits, notably a
prolonged larval dispersal phase that determines settlement to distant reef habitats, thus influencing the spatial
structuring of their populations. They can be very abundant in coral reef ecosystems and represent major mesopredators,
playing a crucial role in food webs. Yet, due to their elusive nature (i.e. cryptic behaviour, nocturnal
activity), these organisms are generally difficult to study and collect. To our knowledge, only a few studies performed
over large geographical and phylogenetic scales have been conducted. We used a unique and cost-efficient
sampling approach, involving forced regurgitation from sea snake predators, to collect large numbers of a widespread
moray eel species (Gymnothorax chilospilus). When combined with the development of 11 new microsatellite
markers, this efficient sampling technique allowed us to examine the genetic structure of Gymnothorax
populations occurring in the South Lagoon of New Caledonia. Analyses revealed a lack of genetic differentiation
among populations. This result echoes the strong genetic homogeneity of populations of their main predator, the
sea snake. This convergence might result from a distinctive trait involved in population functioning of both moray
eels and sea snakes, where immature individuals emerge from common breeding grounds and disperse over long
distances before settlement.