Genetic diversity and demographic history of the leopard seal: A Southern Ocean top predator

• Published in: PloS one 2023-08, Vol.18 (8), p.e0284640-e0284640
• Main Authors: Bender, Arona N, Krause, Douglas J, Goebel, Michael E, Hoffman, Joseph I, Lewallen, Eric A, Bonin, Carolina A
• Format: Article
• Language: English
• Subjects: Aquatic mammals; Bayesian analysis; Biological diversity; Biology and Life Sciences; Climate change; Climatic changes; Demographics; Demography; Earth Sciences; Ecological effects; Ecology and Environmental Sciences; Ecosystem biology; Ecosystems; Fisheries; Genetic aspects; Genetic diversity; Glacial periods; Habitats; Haplotypes; Hydrurga leptonyx; Influence; Last Glacial Maximum; Marine mammals; Mitochondrial DNA; Nucleotides; People and Places; Polar environments; Population; Population genetics; Population growth; Population number; Predators; Prey; Sea ice; Seals; Seals (animals); Trends
• ISSN: 1932-6203; 1932-6203
• DOI: 10.1371/journal.pone.0284640

Leopard seals (Hydrurga leptonyx) are top predators that can exert substantial top-down control of their Antarctic prey species. However, population trends and genetic diversity of leopard seals remain understudied, limiting our understanding of their ecological role. We investigated the genetic diversity, effective population size and demographic history of leopard seals to provide fundamental data that contextualizes their predatory influence on Antarctic ecosystems. Ninety leopard seals were sampled from the northern Antarctic Peninsula during the austral summers of 2008-2019 and a 405bp segment of the mitochondrial control region was sequenced for each individual. We uncovered moderate levels of nucleotide (π = 0.013) and haplotype (Hd = 0.96) diversity, and the effective population size was estimated at around 24,000 individuals (NE = 24,376; 95% CI: 16,876-33,126). Consistent with findings from other ice-breeding pinnipeds, Bayesian skyline analysis also revealed evidence for population expansion during the last glacial maximum, suggesting that historical population growth may have been boosted by an increase in the abundance of sea ice. Although leopard seals can be found in warmer, sub-Antarctic locations, the species' core habitat is centered on the Antarctic, making it inherently vulnerable to the loss of sea ice habitat due to climate change. Therefore, detailed assessments of past and present leopard seal population trends are needed to inform policies for Antarctic ecosystems.