Humpback whale genomes reflect the increased efficiency of commercial whaling

Genetic diversity is declining globally, a trend that may particularly affect exploited populations that must adapt<br/>to rapid environmental change and other threats. Estimated genomic changes in effective population size mirrored<br/>known whaling history and shifts in technology. In the Southern Ocean, a comparison of genomes from<br/>historical and contemporary populations indicated that the contemporary genomes have less diversity and an<br/>elevated realized mutation load for moderately deleterious mutations, likely due to the effects of whaling. Our<br/>results demonstrate that the relatively recent, brief, and marked depletion of humpback whale populations by<br/>whaling likely had subtle but discernible, negative, and lasting effects on the whales’ genomes. Thus, even as<br/>some humpback whale populations are now recovering to pre-exploitation<br/>numbers, they likely do so with a diminished<br/>adaptive capacity in the face of future conditions and threats.