Skip to main content
Dryad

Supporting Data for: Ocean-wide conservation genomics of blue whales suggest new Northern Hemisphere subspecies

Data files

Jan 08, 2025 version files 272.63 MB

Abstract

The blue whale is an endangered and globally distributed species of baleen whale with multiple described subspecies assignments, including the morphologically and molecularly distinct pygmy blue whale, among others. North Atlantic and North Pacific populations, however, are currently regarded as a single subspecies despite being separated by continental land masses and differences in their acoustic communication. To determine the degree of isolation among the Northern Hemisphere populations, fourteen North Pacific and six Western Australian blue whale nuclear and mitochondrial genomes were sequenced and analyzed combinedly with eleven publicly available North Atlantic blue whale genomes. This allowed to contrast the genetic differentiation and genetic exchange among Northern Hemisphere populations to the Western Australian pygmy blue whale subspecies. Population genomic analyses revealed distinctly differentiated clusters and limited exchange among all three populations, indicating a high degree of isolation. Nevertheless, the genomic and mitogenomic distances between all blue whale populations, including the Western Australian pygmy blue whale, are low when compared to other inter-subspecies distances in cetaceans. Given that the pygmy blue whale is an already recognized subspecies and further supported by previously reported acoustic differences, a proposal is made to treat the two Northern Hemisphere populations equally as subspecies, namely Balaenoptera musculus musculus (North Atlantic blue whale) and Balaenoptera musculus sulfureus (North Pacific blue whale). Furthermore, a first molecular vitality assessment of all three populations found a generally high genomic diversity among blue whales but also a lack of rare alleles, non-neutral evolution and substantially increased effects of inbreeding. This suggests a substantial anthropogenic impact on the genotypes of blue whales and calls for careful monitoring in future conservation plans.