Northern elephant seal genetics

https://www.nature.com/articles/s41559-024-02533-2
This article is open access.
The Northern elephant seal was hunted to near extinction, but a small population survived on some out of the way island.  Likely due to most males not producing offspring the paper estimates that the effective population size was only 6 at the point of the genetic bottleneck.  This is about the effective population size of Noah and his family of flood survivors if they all managed to produce a boat load of progeny each.
Not surprisingly this population has a lot less genetic diversity than the Southern population that did not suffer the same near extinction event.  Surprisingly, individuals do not seem to be suffering from inbreeding depression.  It may be that the surviving breeders had less than the average genetic load, so the extant population has fewer deleterious variants.
The Northern and Southern populations are closely related and they likely could reintroduce genetic variation from the South, but since they don't seem to be suffering from inbreeding depression my take is that they should allow the population to continue as an independent population and see if it eventually takes over both the Northern and Southern territories.  These lucky population expansions have had to happen every once in a while for all species.
Large stable populations will tend to accumulate recessive lethal and sub lethal variants.  Eugenics failed because it was never going to work.  Even if you have 100% selection against the homozygotes a recessive lethal will not be effectively selected against once the allele frequency drops to around 0.03 (6% of the population are still carriers).  There are thousands of recessive lethals segregating in the human population.  In order to reduce the genetic load you need to get lucky with some sub population that due to founder effects/genetic drift do not have as many recessive lethals.  Most small sub populations likely fail in isolation because they were not lucky and inbreeding depression will wipe them out, but once in a while some sub population will come out cleaner than the parent population.  It could be the reason that we see allopatric speciation events and Gould and Eldridge's punctuated fossil record.  A slightly different sub species comes back and takes over the parental population's territory.
Ron Okimoto