Comparative population genomics of manta rays has global implications for management

 November 2023

Emily Humble, Jane Hosegood, Gary Carvalho, Mark de Bruyn, Simon Creer, Guy M. W. Stevens, Amelia Armstrong, Ramon Bonfil, Mark Deakos, Daniel Fernando, Niv Froman, Lauren R. Peel, Stephen Pollett, Alessandro Ponzo, Joshua D. Stewart, Sabine Wintner & Rob Ogden

Keywords: Conservation Genomics • Fisheries Management • Genetic Diversity • Population Structure • ddRAD

Summary: Understanding the genetic diversity and connectivity of marine megafauna is crucial for conservation. Despite challenges posed by their elusive nature and vast distributions, such knowledge is essential for effective management. This study focuses on manta rays, comparing the genetic differentiation and diversity of oceanic manta rays and reef manta rays. Results show higher heterozygosity in oceanic manta rays and greater global connectivity, suggesting the influence of contemporary and historical factors. The findings emphasise the potential impact of fisheries on population dynamics, urging international conservation efforts for marine species.

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 heterozygosity than reef manta rays (Mobula alfredi) and that M. birostris populations display higher connectivity worldwide. Through inferring modes of colonization, 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 conservation of marine species.”

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Author Affiliations

  • Royal (Dick) School of Veterinary Studies and the Roslin Institute, University of Edinburgh

  • The Manta Trust

  • Molecular Ecology and Evolution Group, Bangor University

  • Australian Research Centre for Human Evolution, Griffith University

  • School of Biomedical Sciences, The University of Queensland

  • Océanos Vivientes AC

  • Consejo Nacional de Humanidades Ciencia y Tecnología (CONAHCyT)

  • El Colegio de la Frontera Sur, Unidad Chetumal

  • Hawai'i Association for Marine Education and Research

  • Blue Resources Trust

  • Save Our Seas Foundation

  • School of Biological Sciences, Oceans Institute and Oceans Graduate School, The University of Western Australia

  • Large Marine Vertebrates Research Institute Philippines

  • Ocean Ecology Lab, Marine Mammal Institute, Department of Fisheries, Wildlife & Conservation Sciences, Oregon State University

  • KwaZulu-Natal Sharks Board

  • School of Life Sciences, University of KwaZulu-Natal

Funded by

  • Natural Environment Research Council

  • Save Our Seas Foundation

  • The People's Trust for Endangered Species

  • Marine Conservation Action Fund by New England Aquarium