Researchers find evidence of inbreeding in B.C. killer whales

Two male southern resident killer whales have fathered most of the population’s calves, a new study has found, and that is raising the spectre of inbreeding.

'We don’t know what the potential consequences are for the southern resident killer whales,' says geneticist

Research from the NOAA have published research results that discovered evidence of inbreeding among the resident killer whales in B.C. waters. (C. Emmons/NOAA Fisheries)

Two male southern resident killer whales off B.C.'s West Coast have fathered most of the population's calves, a new study has found, a development that has raised the spectre of inbreeding.

The species' numbers are dwindling and scientists are concerned that mating between closely related individuals could lead to genetic disorders and decrease the population's fitness.

"There are some indications of breeding between close relatives," marine mammal geneticist Kim Parsons told All Points West host Jason D'Souza.

"Trying to understand what the consequences of that could be are difficult," Parsons said.

"It could be related to survivorship of individuals or reduced fecundity. It's thought to be related to immune function and potential expression of lethal genes, for example.

"We don't know what the potential consequences are for the southern resident killer whales."

It's not clear what the implications of the inbreeding are, a researcher said. (C. Emmons/NOAA Fisheries)

Parsons, with the U.S. National Oceanic and Atmospheric Administration, is a co-author of a new study published in the journal Animal Conservation that genetically analyzed skin samples and fecal samples from calves and identified the calves' fathers from the samples.

They found two males fathered the bulk of the calves and seven other males fathered one or two calves each.

It's not clear why the two males fathered so many calves, Parsons said. They are the biggest and oldest males but it's not known if those are the only factors.

Parsons says she would like to explore how common inbreeding is among other resident killer whale populations, and what effects this has on individual whales.

Listen to the full interview:

Two male southern resident killer whales have fathered most of the population’s calves, a new study has found, and that is raising the spectre of inbreeding. 5:37

With files from CBC Radio One's All Points West