Comparative population genomics of manta rays has global implications for management

Abstract

Understanding population connectivity and genetic diversity is of fundamental importance to conservation. However, in globally threatened marine megafauna, challenges remain due to their elusive nature and wide-ranging distributions. As overexploitation continues to threaten biodiversity across the globe, such knowledge gaps compromise both the suitability and effectiveness of management actions. Here, we use a comparative framework to investigate genetic differentiation and diversity of manta rays, one of the most iconic yet vulnerable groups of elasmobranchs on the planet. Despite their recent divergence, we show how oceanic manta rays(Mobula birostris)display significantly higher genetic diversity than reef manta rays(Mobula alfredi)and thatM. birostrispopulations display higher connectivity worldwide. Through reconstructing modes of colonisation, we reveal how both contemporary and historical forces have likely influenced these patterns, with important implications for population management. Our findings highlight the potential for fisheries to disrupt population dynamics at both local and global scales and therefore have direct relevance for international marine conservation.TeaserPopulation genomics of manta rays reveals striking differences in differentiation and diversity between two recently diverged species.

Spatiotemporal variations in reef manta ray (Mobula alfredi) residency at a remote meso‐scale habitat and its importance in future spatial planning

“…One such species is the reef manta ray (Mobula alfredi), a zooplanktivorous elasmobranch species of the monogeneric Mobulidae family (mobulids) (Hosegood et al, 2020;Marshall et al, 2009;Notarbartolo di Sciara et al, 2020;White et al, 2017). Reported M. alfredi populations throughout their Indo-West Pacific range are small (typically a few hundred), geographically fragmented and often isolated (Couturier et al, 2012;Hosegood et al, 2020;Humble et al, 2023;Kashiwagi et al, 2011;Whitney et al, 2023). Many of these populations have faced declines, predominantly driven by targeted and non-targeted fisheries (Rohner et al, 2013;Rohner et al, 2017;Ward-Paige et al, 2013).…”