Two whale groups separated by seas—but not by genes, study finds

April 28, 2026 Two whale groups separated by seas—but not by genes, study finds by Oxford University Press edited by Sadie Harley, reviewed by Robert Egan Sadie Harley scientific editor Meet our editorial team Behind our editorial process Robert Egan associate editor Meet our editorial team Behind our editorial process Editors' notes This article has been reviewed according to Science X's editorial process and policies. Editors have highlighted the following attributes while ensuring the content's credibility: fact-checked peer-reviewed publication trusted source proofread The GIST Add as preferred source Credit: Pixabay/CC0 Public Domain A paper in Genome Biology and Evolution discovers that the endangered Mediterranean fin whale is not completely isolated from Atlantic groups. Both Atlantic and Mediterranean populations have declined for the past 200,000 years. Considering more recent threats to the whales, this finding has important implications for conservation, particularly considering increasing anthropogenic pressures. The paper is titled "One Sea, Different Whales: Genomics Sheds Light on a Small Population of Fin Whales." Why whales and their genomes matter Whales have long captured human fascination, due to their massive size but also because of their complex behaviors, migratory patterns, and ecological importance. Whales play a crucial role in maintaining ocean ecosystems by redistributing nutrients on which other marine life depends. Whales face increasing environmental pressures, from climate change to human-induced disturbances. As the climate crisis accelerates, genomic studies have become essential tools for investigating population structure, evolutionary history, and patterns of isolation in order to facilitate conservation efforts. A closer look at Mediterranean fin whales The fin whale (Balaenoptera physalus) is the second-largest whale species on Earth, second only to the blue whale. Despite its classification as endangered, the fin whale from the Mediterranean Sea remains poorly characterized at the genomic level. Scientists previously identified the Mediterranean fin whale population as distinct from the North Atlantic populations through studies of sounds and whale tracking. Previous studies suggested the presence of both sedentary and migratory whale subgroups within the Mediterranean Sea. However, genetic characterization of this fin whale population has been limited, with only partial evidence for differentiation and possible gene flow. Genomic comparisons across ocean basins Researchers attempted to reconstruct the Mediterranean fin whale's genetic structure, as well as its demographic and evolutionary history. The investigators inferred the potential for adaptation and vulnerability to increasing environmental disturbances by using the estimated level of genomic variability within the Mediterranean population. By comparing genomes from the Mediterranean group with those of fin whales from the North Atlantic, North Pacific, and new sequences from the Sea of Cortez, researchers evaluated the degree of genetic isolation and placed the Mediterranean population within a broader evolutionary and conservation context. What the findings mean for conservation The results show that although Mediterranean fin whales form a distinct genetic cluster, they are not fully isolated from North Atlantic populations. They also detected genetic differences within the Mediterranean group, with some individuals showing no…

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