West Coast Orca Population Falls to Lowest Level for Almost 50 Years

A population of orca that resides off the West Coast is at its lowest level in almost 50 years, with just 73 individuals now remaining.

The Southern Resident killer whale population has not fallen below this number since 1974, when the first complete count was undertaken.

The 2021 Southern Resident Killer Whales (Orcinus orca) 5-Year Review was published by the National Oceanic and Atmospheric Administration (NOAA) on January 4. In it, authors said there were 74 individuals in the census carried out in July 2021, but that one adult male had been lost, presumed dead, leaving the total at 73.

The Southern Resident killer whale population consists of three pods made up of family groups. They spend the summer in Washington State's Puget Sound and travel along the West Coast, having been spotted as far south as California, up to Canada.

Population numbers fell in the 1960s as many were captured to be sent to marine parks. This was stopped by the Marine Mammal Protection Act enacted in 1972 and the population started to recover, peaking in 1996 when 97 orca were counted.

But soon after numbers started to decline, falling into the 70s in the 2000s. The population was listed as an endangered species in 2005 and efforts are being made to recover it. The latest report, however, suggests impacts of these efforts are yet to be seen.

The report says a catastrophic event, such as an oil spill, could impact the entire population. It also lists threats such as prey availability, contaminants in the water and interactions with vessels as being highly likely and having a severe impact on the pods.

Dr. Meg Wallen, marine mammal specialist in NOAA Fisheries' West Coast Region, led the five-year review. She told Newsweek the last five years have seen incredible work and progress in understanding these whales and the threats facing them.

"The Southern Resident population is closely studied and monitored year-round by researchers, government agencies, non-profit organizations, industry, and even the general public," she said. "So while we knew the number of whales in the population, the results underscore the need for continued focus on the primary threats to the whales' survival. We hope to see slow, incremental growth with surviving calves each year."

A study published in 2020 looked at the cause of deaths of orca stranded in the Pacific Ocean between 2004 and 2013. Researchers found calves tended to be killed by infectious diseases, nutritional deficiencies and malformations. Adult deaths were caused by trauma, blunt force trauma, malnutrition, infectious diseases, emaciation, and bacterial infections. The authors concluded that "death related to human interaction was found in every age class."

Wallen said recovering the Southern Resident orca population is a long-term process, especially for high-level predators like these. "When working in a natural environment with many ecological and human factors at play, it often takes years, even decades, to see the benefits or significant progress," she said. "For example, the additional hatchery production will take a few years to deliver adult salmon to the whales. Last year some of the whales appeared to be in improved condition, based on aerial photographs that help reveal their health and growth."

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Stock photo of a member of the Southern Resident killer whale in Juan de Fuca strait Getty Images

Colleen Weiler, from the wildlife charity Whale and Dolphin Conservation, says the continued decline of the Southern Resident orcas is "very concerning." She told Newsweek that while she welcomes the population being recognized as endangered and in need of protection, it is "frustrating" that the population has shown no sign of recovery since it was listed. "I would love to see signs of progress, but this...shows that recovery efforts to date have not been enough to turn things around for the Southern Residents," she said.

Weiler says she believes the decline is because recovery efforts have not been sufficient to protect and recover the population. "The biggest challenge facing the Southern Resident population is a lack of political will to address these issues," she said. "The silver lining is that we know what needs to happen to reverse their decline and ensure the next 5-year report has some positive news."

She said to protect the population, more investment must be made in habitat protection and restoration, as well as removing dams to provide the orca with more salmon, cleaning up ports and reducing shipping noise.

"So far, elected officials and agency leadership have been unwilling to make the commitments needed to see big progress. We have seen positive steps at the state level, and the recently passed Infrastructure Act includes a lot of funding for salmon recovery, but it will take time to see those result in more salmon, better water quality, and more babies for the Southern Resident orcas—and much more is needed to ensure this special community does not go extinct."