Genetic structure of the Doughboy scallop (Mimachlamys asperrima)

Scallops are among the most commercially valuable marine catches and contribute vital ecosystem functions. Doughboy scallops (Mimachlamys asperrima) are broadly distributed along temperate southern coastline of Australia, an area with notable biogeographical barriers for some marine organisms. Traditional methodologies for scallop identification that rely on morphological characters are hindered by bivalves’ morphological plasticity and by convergent evolution. Furthermore, M. asperrima exhibits relatively high levels of geographic variation in size and shell morphology thereby heightening the challenge for identification and raising questions regarding taxonomy over the reported range. Using mitochondrial 16S data, I have confirmed morphologically identified M. asperrima collected from two Western Australian sites (n=43) and one site in New South Wales (n=31) with two major haplotypes representing a majority individuals at all three locations. Analysis of 5,897 nuclear single nucleotide polymorphisms revealed significant genetic divergence between individual sites. This study affirms the morphological species identification using molecular data, and provides preliminary insights into population delimitation, critical for both potential aquaculture utilisation and conservation management of M. asperrima.