Why do killer whales off the US west coast keep dying? Chinese and American gene scientists have an answer
- Inbreeding is killing off ‘southern resident’ killer whales, US-Chinese joint research published in Nature Ecology & Evolution finds
- Conservation should focus not only on external but genetic factors as well, warns study which included scientists from US-sanctioned BGI-Research
The genetic threat, however, is not observed in other North Pacific orcas, according to the study published on Tuesday in the peer-reviewed journal Nature Ecology & Evolution.
The “southern residents” had the lowest levels of genetic variation and the highest level of inbreeding among the sampled North Pacific killer whale populations, genome sequencing of 100 living and dead members of the group revealed.
Inbreeding – or reproduction between genetically closely related parent organisms – reduces genetic diversity and is known to cause reduced biological fitness, or “inbreeding depression”. This involves a reduced ability to fight environmental stress and greater disease vulnerability, alongside higher juvenile mortality and lower fertility – thus decreasing the viability of wild populations.