SEATTLE — It’s well-known the Southern Resident killer whale population is in danger of extinction.
But a new study published Thursday details just how much killer whales are struggling, and how hard it will be to bring the iconic Northwest marine animals back from the brink.
The study, titled “Evaluating anthropogenic threats to endangered killer whales to inform effective recovery plans,” also outlines the massive collaboration needed to keep the population alive more than 100 years. Collaboration that at points seems impossible.
“One key finding we have is if you fix just one thing it won’t be enough,” said one of the scientific study’s co-authors Robert Lacy. “Just improving the salmon stocks or reducing the sound, it’s not enough.”
There are three primary, current threats to the orca population around the Puget Sound. First, the Chinook salmon population, its preferred food source, is dwindling. Second, increased boat noise and disturbance is limiting foraging ability. Finally, pollution in the Puget Sound strains the delicate mammals.
The study says a "conservation goal" for maintaining a viable population should be an annual population growth of 2.3 percent -- a growth we haven't seen in a while as the population continues to decline.
Limitation of the orcas' prey is the most important factor impacting the population, the study says. In order to reach needed population growth on increased prey alone, Chinook salmon abundance would have to be sustained near the highest levels since the 1970s.
Though this seems unlikely in the near future, improving the Chinook stock even the slightest bit is of utmost importance to the 76 or so Southern Resident killer whales remaining.
Steps also need to be made to reduce boat noise around orcas. Killer whales emit high-frequency clicks to forage for salmon. Extending boat-free zones may be necessary to help alleviate the noise in waters crowded by small, personal crafts.
"High-frequency noise from small, outboard vessels that follow whales might cause a greater reduction in killer whale's foraging success than low-frequency background noise from commercial shipping," the study says.
The study shows that cutting boat noise by half and increasing salmon populations by about 15 percent may allow the orcas to reach the 2.3 percent annual growth needed for long-term viability.
But as lack of Chinook, boat noise and pollutants are the most pressing issues, other dangers exist. The study doesn't take into account things like a massive oil spill or a sickness; both which could decimate the population beyond repair.
"A single disease or localized incident could be catastrophic," Lacy said.
The orca also lacks a bevy of breeding males, Lacy said. If a dominant male dies, or if a pod goes through a couple years of disruptive social times, the struggling population could falter.
"The lower the numbers, the more trouble you have," Lacy said.
Lacy, who has spent much of his career studying endangered animals and what steps are needed to improve their populations, says as daunting as the task may be, it's not without hope.
The Southern Resident orcas are adjacent to first-world countries, and those countries can do what's needed to help the whales, he says. The desire to help save one of the Northwest's most iconic species must be there.
"There is a lot to do, economically and technologically, to turn it around," Lacy said. "The will needs to be there."