A recent global study has highlighted the genetic consequences of hunting on northern elephant seals. Published today in Nature Ecology and Evolution, the findings indicate that this species narrowly avoided extinction due to hunting, which has led to enduring genetic effects in their current population. This study, spearheaded by Bielefeld University, involved fifteen researchers from Germany, the UK, and the USA, representing seven universities and four research institutions.
In the early 1900s, northern elephant seals were almost extinct due to hunting. ‘Genetic studies indicate that at that time, the population was likely reduced to fewer than 25 individuals,’ states Professor Dr. Joseph Hoffman, the leading author of the study and director of the Evolutionary Population Genetics group at Bielefeld University. Such drastic reductions in population can diminish a species’ genetic diversity, heightening the risk of inbreeding and endangering survival. Fortunately, the population of northern elephant seals has rebounded to approximately 225,000 today. The research in ‘Nature Ecology and Evolution’ explores how this near-extinction event has affected the species’ genetic diversity and overall health.
Threatened adaptability
The scientists utilized a combination of genetic information, health data, modeling of population sizes, and genetic simulations in their analysis. Their results indicate that the significant decline in population resulted in the loss of many advantageous and detrimental genes from the northern elephant seal’s genetic makeup. Such a pattern was not seen in the southern elephant seal, a closely related species that did not suffer a similar drastic decline.
‘The significant reduction in genetic diversity, including the loss of beneficial gene variants, may hinder northern elephant seals’ ability to adapt to future ecological shifts, which could stem from human-induced climate change, alterations to their habitat, or even natural calamities like disease outbreaks,’ cautions Professor Dr. Kanchon K. Dasmahapatra from the University of York, the senior author of the study.
Unexpected findings on inbreeding
Every species carries certain harmful mutations, although their effects typically remain masked. However, inbred animals may encounter health complications as these mutations surface. ‘We investigated several important health factors in these seals, such as body weight, fat thickness, and vulnerability to diseases. To our surprise, we found no evidence of health issues linked to inbreeding,’ says Joseph Hoffman. ‘We think the drastic population decrease may have purged many harmful mutations.’
Importance for conservation efforts
‘Our research highlights how a species’ distinct population history influences its genetic diversity,’ remarks Dasmahapatra. These results provide crucial insights for conservation initiatives and ecosystem management. Hoffman emphasizes: ‘Our study highlights the necessity of understanding a species’ background when formulating conservation plans. Each species faces threats differently, so tailored strategies are vital.’
