Unveiling the Genetic Structure of New Caledonian Dugongs Using a Multiscale Genetic Approach: Conservation...

Area of Science:

• Marine Biology
• Conservation Genetics
• Population Genomics

Background:

• Coastal megafauna face increasing threats, necessitating conservation.
• The New Caledonian dugong population was listed as Endangered in 2021, with fewer than 800 individuals.
• Understanding genetic diversity and population structure is vital for effective conservation.

Purpose of the Study:

• To assess the genetic diversity and population structure of the New Caledonian dugong.
• To compare the genetic distinctiveness of New Caledonian dugongs with Australian populations.
• To inform urgent conservation strategies for this vulnerable species.

Main Methods:

• Analysis of 66 dugong skin samples (2003-2023).
• Multiscale genetic approach using mitochondrial DNA, microsatellites, and single nucleotide polymorphisms (SNPs).
• Examination of genetic differentiation and gene flow across New Caledonia's lagoon habitats.

Main Results:

• Extremely low genetic diversity and high genetic differentiation from Australian dugongs.
• Critically low effective population size (Ne) estimated between 95-160 individuals.
• Identification of two genetically distinct dugong clusters along New Caledonia's west coast, separated by Bourail.

Conclusions:

• The New Caledonian dugong population is highly isolated with severe genetic diversity loss.
• Conservation actions are urgently required to prevent further decline.
• The findings suggest a potential reclassification to Critically Endangered status.