Population and seascape genomics of a critically endangered benthic elasmobranch, the blue skate Dipturus batis

Delaval, Aur�lien; Frost, Michelle; Bendall, Victoria; Hetherington, Stuart J.; Stirling, David; Hoarau, Galice; Jones, Catherine S.; Noble, Leslie R.

Abstract

The blue skate (Dipturus batis) has a patchy distribution across the North-East Atlantic Ocean, largely restricted to occidental seas around the British Isles following fisheries-induced population declines and extirpations. The viability of remnant populations remains uncertain, and could be impacted by continued fishing and bycatch pressure and the projected impacts of climate change. We genotyped 503 samples of D. batis, obtained opportunistically from the widest available geographic range, across 6,350 single nucleotide polymorphisms (SNPs) using a reduced-representation sequencing approach. Genotypes were used to assess the species’ contemporary population structure, estimate effective population sizes, and identify putative signals of selection in relation to environmental variables using a seascape genomics approach. We identified genetic discontinuities between inshore (British Isles) and offshore (Rockall and Faroe Island) populations, with differentiation most pronounced across the deep waters of the Rockall Trough. Effective population sizes were largest in the Celtic Sea and Rockall, but low enough to be of potential conservation concern among Scottish and Faroese sites. Among the 21 candidate SNPs under positive selection was one significantly correlated with environmental variables predicted to be affected by climate change, including bottom temperature, salinity, and pH. The paucity of well annotated elasmobranch genomes precluded us from identifying a putative function for this SNP. Nevertheless, our findings suggest that climate change could inflict a strong selective force upon remnant populations of D. batis, further constraining its already restricted habitat. Furthermore, the results provide fundamental insights on the distribution, behaviour, and evolutionary biology of D. batis in the North-East Atlantic that will be useful for the establishment of conservation actions for this and other critically endangered elasmobranchs.

Citation

Delaval, A., Frost, M., Bendall, V., Hetherington, S. J., Stirling, D., Hoarau, G., …Noble, L. R. (2022). Population and seascape genomics of a critically endangered benthic elasmobranch, the blue skate Dipturus batis. Evolutionary Applications, 15(1), 78-94. https://doi.org/10.1111/eva.13327

• Journal Article Type: Article
• Acceptance Date: Nov 22, 2021
• Online Publication Date: Nov 26, 2021
• Publication Date: 2022-01
• Deposit Date: Nov 29, 2021
• Publicly Available Date: Dec 15, 2021
• Journal: Evolutionary Applications
• Print ISSN: 1752-4563
• Electronic ISSN: 1752-4571
• Publisher: Wiley
• Peer Reviewed: Peer Reviewed
• Volume: 15
• Issue: 1
• Pages: 78-94
• DOI: https://doi.org/10.1111/eva.13327
• Keywords: Blue skate, climate change, conservation, Dipturus batis, population genomics, seascape genomics
• Public URL: http://researchrepository.napier.ac.uk/Output/2824760