Sex-crazed pod of killer whales ‘wiping itself out’ with deep-sea incest campaign as grim evidence found off US coast

INBREEDING can lead to a pod of endangered killer whales dying off at an alarming rate, a new study finds.

Off the coast of North America in the Pacific Ocean lives an intimate pod of 73 Southern killer whales that are currently on endangered animal lists in both the United States and Canada.

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However, the pod is so isolated from other orca communities that it resorts to inbreeding, a new study published in the journal natural ecology and evolution found.

This, in turn, has contributed to the species’ rapid decline – an idea scientists have long theorized but have not proven until now.

Thanks to an international team of researchers, new evidence was found that the orca group exhibited “lower levels of genetic diversity” and “higher levels of inbreeding”.

The study, which looked at 100 dead and live southern orcas, is related to other populations in the North Pacific.

One reason for the pod’s isolation is that they are not genetically inclined to migrate further than British Columbia to the north and Oregon to the south.

“They’re a little more genetically isolated from other populations,” study co-author Michael Ford, a research scientist at the National Oceanic and Atmospheric Administration’s (NOAA) Northwest Fisheries Science Center in Seattle, told Live Science.

“There are also less episodic crossovers between them [them and] other populations.”

The researchers added that their analysis of their group’s genetics helped them understand why the community isn’t thriving, according to a NOAA statement

“Sequencing revealed that several of the whales were the result of inbreeding between a parent and one of their children,” Ford told Live Science.

“Another 20 percent were bred between first cousins,” Ford added. “Inbreeding is definitely a problem for this population.”

For this reason, according to NOAA, a southern resident orca has “less than half the chance of surviving their prime to reach 40 compared to the least inbred individuals.”

Low-inbreed female orcas live long enough to sire an average of 2.6 offspring over their lifetime.

However, those with a higher degree of inbreeding produce an average of 1.6 offspring during their shorter lives.

For an animal population to remain stable or increase in number, at least two surviving offspring must be produced per female, NOAA noted.

However, inbreeding is not the only factor leading to the decline in orca species.

Scientists also pointed to shipping and man-made pollution as major culprits.

“Some of their most important habitats are in an urban environment with lots of small boats and large shipping traffic, which can directly disrupt them or impair their ability to hunt for salmon effectively,” Ford said.

“They are also known to be quite contaminated with both old and newer contaminants.”

Brad Hanson, a research scientist at the Northwest Fisheries Science Center in Seattle who is leading the fieldwork on the whales, said, “The whales don’t necessarily die from inbreeding themselves, they die prematurely because inbreeding has made them more susceptible to diseases or other problems.”

“We need to minimize the potential for these factors to impact.”