Population genetics of Ylistrum balloti (Bernardi, 1861) in Western Australia

<p dir="ltr">Global scallop stocks are highly vulnerable to changes in their local environmental conditions. Climate change and the increasing frequency of marine heatwaves are particularly influential, causing large fluctuations in annual macroinvertebrate yields, such as the saucer scallop, <i>Ylistrum balloti</i>. This is a primary target species for fisheries in Western Australia. This variability has prompted interest in the development of ex-situ management strategies. Information on the population structure, effective population size (<i>Ne</i>) and genetic variation within the west coast population is critical for ensuring sustainable population management. To date, high resolution genetic data for these key population features are limited for <i>Y. balloti. </i>This study aims to address these knowledge gaps by evaluating genetic structure and <i>Ne </i>using single-nucleotide polymorphisms (SNPs). This investigation revealed the presence of two distinct genetic stocks of <i>Y. balloti </i>along a ~2000km stretch of coastline in southwest Western Australia. Fine-scale spatial analyses revealed a lack of isolation by distance, however there was evidence of elevated genotypic similarity at lower geographic distances. Both stocks were found to have high <i>Ne</i>, with no evidence of a recent genetic bottleneck identified. The results presented in this study will contribute to the development of effective management strategies tailored to the spatial structure and connectivity patterns identified. To preserve genetic variation and potential localised adaptation, consideration of these two genetic stocks as separate management units is recommended.</p>