Demographic reconstruction of Antarctic fur seals supports the krill surplus hypothesis

Hoffman, Joseph I. ORCID: https://orcid.org/0000-0001-5895-8949; Chen, Rebecca S.; Vendrami, David L.J.; Paijmans, Anna J.; Dasmahapatra, Kanchon K.; Forcada, Jaume ORCID: https://orcid.org/0000-0002-2115-0150. 2022 Demographic reconstruction of Antarctic fur seals supports the krill surplus hypothesis. Genes, 13 (3). 541. https://doi.org/10.3390/genes13030541

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Abstract/Summary

Much debate surrounds the importance of top-down and bottom-up effects in the Southern Ocean, where the harvesting of over two million whales in the mid twentieth century is thought to have produced a massive surplus of Antarctic krill. This excess of krill may have allowed populations of other predators, such as seals and penguins, to increase, a top-down hypothesis known as the ‘krill surplus hypothesis’. However, a lack of pre-whaling population baselines has made it challenging to investigate historical changes in the abundance of the major krill predators in relation to whaling. Therefore, we used reduced representation sequencing and a coalescent-based maximum composite likelihood approach to reconstruct the recent demographic history of the Antarctic fur seal, a pinniped that was hunted to the brink of extinction by 18th and 19th century sealers. In line with the known history of this species, we found support for a demographic model that included a substantial reduction in population size around the time period of sealing. Furthermore, maximum likelihood estimates from this model suggest that the recovered, post-sealing population at South Georgia may have been around two times larger than the pre-sealing population. Our findings lend support to the krill surplus hypothesis and illustrate the potential of genomic approaches to shed light on long-standing questions in population biology.

Item Type:	Publication - Article
Digital Object Identifier (DOI):	https://doi.org/10.3390/genes13030541
ISSN:	2073-4425
Additional Keywords:	Arctocephalus gazella; Antarctic fur seal; RAD sequencing; demographic modelling; bottleneck; krill surplus hypothesis; marine mammal; baleen whales; pinnipeds
Date made live:	28 Mar 2022 09:38 +0 (UTC)
URI:	https://nora.nerc.ac.uk/id/eprint/532327

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