- A Japanese study decoded why radioactive pig-boar hybrids are rising in Fukushima
- Domestic pigs escaped farms and bred with wild boars after the 2011 nuclear accident
- Hybrids inherited domestic pigs' year-round reproduction and larger litter traits
A new Japanese study has decoded why the population of radioactive pig-boar hybrids is on the rise in Fukushima, the epicentre of the 2011 Fukushima Daiichi Nuclear Power Plant (FDNPP) accident. Though humans do not live in the region anymore, domestic pigs from nearby farms escaped and joined radioactive wild boars in the area, mating with them. The study, published in the Journal of Forest Research, analysed the DNA of these hybrids and found that over time, the genes of domestic pigs were overwritten by those of boars. However, not all of their traits were lost.
Unlike their wild counterparts, which typically breed once a year, these hybrids retained the domestic pig's ability to reproduce year-round with larger litters. This inherited super-breeding has allowed the population in Fukushima to explode despite tests by the Japanese government showing elevated radioactivity levels, particularly cesium-137, among wild boars.
"These results imply that the shorter reproductive cycle of domestic swine may have accelerated the dilution of swine nuclear genomes within wild boar populations following the FDNPP accident," the study showed.
These findings offer insights for wildlife management and damage control strategies for invasive species globally, particularly regarding population explosion risks.
"While it has been previously suggested that hybridisation between rewilded swine and wild boars can contribute to population growth, this study demonstrates, through the analysis of a large-scale hybridisation event following the Fukushima nuclear accident, that the rapid reproductive cycle of domestic swine is inherited through the maternal lineage," explained Shingo Kaneko, the lead study author.
Not Limited To Fukushima
The researchers highlighted that the findings were not limited to Fukushima and that "this mechanism likely occurs in other regions worldwide where feral pigs and wild boars interbreed". Such hybridisation is a growing concern worldwide, but the biological mechanism behind these changes has remained poorly understood. The new study, however, aims to change the perspective.
"By understanding that maternal swine lineages accelerate generation turnover, authorities can better predict population explosion risks."
The study findings could help with targeted control efforts, including prioritising the removal of hybrid animals so that their invasive population does not hurt the local wildlife.
