A multitude of factors are harming Puget Sound’s local population of endangered orcas: water pollution, noise, loss of habitat.
But topping that list right now for many scientists is recovery of their primary food source: Chinook salmon.
The tragic scenes captured on the water over the past week – of the grieving orca J35 incessantly carrying her deceased calf, and of 4-year-old J50 ill and starving – are sad events, but not surprising to scientists working on orca recovery.
They say they established years ago that when Chinook salmon are scarce, local orcas become sick and unable to effectively reproduce.
“This is just a really conspicuous example of it,” said Sam Wasser, who directs the Center for Conservation Biology at the University of Washington.
He’s part of a team of scientists that has done DNA and hormone analysis of orca scat collected by sniffer dogs. They’ve proved that when pregnant orcas are low on food and start metabolizing their blubber, toxins are released into their bloodstream that cause them to miscarry.
And infant mortality spikes when there’s not enough Chinook.
“You can see the runs that are the lowest and that’s when the toxin levels are the highest, the miscarriage rates the highest," Wasser said. "So there’s really no question about that."
He says removing dams on the Columbia River system and restoring Chinook habitat wherever possible should be a top priority as a state task force looks at ways to help the ailing orcas.
A coalition of environmental groups called the Orca Salmon Alliance will deliver more than 43,000 signatures to that effect Tuesday in Wenatchee, where the task force is meeting. The groups want bold and decisive action to help the region’s critically endangered killer whales. And they list prioritizing salmon restoration for orcas as their top priority.
Federal scientists share that goal. Lynne Barre is a marine biologist working with NOAA Fisheries in Seattle to recover the orcas. She says they’re using the latest science to advise the task force.
“We worked with the scientific information to try and identify which of those Chinook stocks overlap the most with the whales and are the highest priority for us to target recovery efforts,” she said.
Barre says other primary areas of focus for recovery are reducing contaminants in the water that can make orcas sick and reducing stress and noise from vessel traffic near them.
Gov. Jay Inslee convened the task force in May after issuing an executive order directing state agencies to take urgent action to support orca recovery and sustainability into the future.
The population of southern resident orca whales is now at a 30-year low of just 75, after a member of the L-pod went missing in June.