Trends in population genetic diversity in the marine fauna of the Western Indian Ocean

Abstract

The Western Indian Ocean (WIO) region has a rich marine biodiversity, spanning a wide range of habitats. Information on population genetic structure – the distribution of genetic variation within and among populations of the same species – is a key input for determining stock structure in fisheries management, and for spatial conservation of genetic diversity in protected areas. This paper synthesised studies on the population genetic structure of marine fauna in the WIO published between 2005 and 2024. Articles were screened in duplicate and assessed against pre-specified inclusion and exclusion criteria as adapted in the Preferred Reporting Items for Systematic Reviews (PRISMA). A summary of patterns by taxonomic group, trends in years, and the genetic markers used, was conducted. The review scored 87 studies, which reveal complex population genetic structure patterns across the region, some finding significant population subdivision, and others finding panmictic populations over large geographical areas. The study highlighted the mitochondrial Cytochrome Oxidase subunit I (COI) as the most common marker used in population genetic studies conducted in the WIO, with a clear increasing trend in the number of studies published over the past two decades. Despite progress, gaps remain in the integration of genetic studies and oceanographic modelling, and the use of genome-wide markers such as the Single Nucleotide Polymorphisms (SNPs) is very limited.