A lack of spatial genetic structure of Gymnothorax chilospilus (moray eel) suggests peculiar population functioning

International audienceMoray 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 aprolonged larval dispersal phase that determines settlement to distant reef habitats, thus influencing the spatialstructuring 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, nocturnalactivity), these organisms are generally difficult to study and collect. To our knowledge, only a few studies performedover large geographical and phylogenetic scales have been conducted. We used a unique and cost-efficientsampling approach, involving forced regurgitation from sea snake predators, to collect large numbers of a widespreadmoray eel species (Gymnothorax chilospilus). When combined with the development of 11 new microsatellitemarkers, this efficient sampling technique allowed us to examine the genetic structure of Gymnothoraxpopulations occurring in the South Lagoon of New Caledonia. Analyses revealed a lack of genetic differentiationamong populations. This result echoes the strong genetic homogeneity of populations of their main predator, thesea snake. This convergence might result from a distinctive trait involved in population functioning of both morayeels and sea snakes, where immature individuals emerge from common breeding grounds and disperse over longdistances before settlement