Southern Resident Killer Whales in the Salish Sea: Population Decline, Vessel Noise, and Salmon Shortages

Scientific American visits the San Juan Islands to examine the southern resident killer whales, a small fish-eating population currently estimated at about 74 individuals. The episode profiles Deborah Giles and her team, including Eva the rescue dog trained to sniff whale poop to locate samples for lab analysis, and explains how Chinook salmon declines, vessel noise, and pollution threaten their survival. It also explores how funding and administrative changes in the federal government in recent years affect endangered species research, prompting concerns about future recovery efforts. The program points listeners to a January feature story and a documentary that expand on the researchers' work and the ongoing conservation challenges facing these orcas.

Overview: The San Juan Islands as a whale research hotspot

The episode follows a Scientific American team as they visit the San Juan Islands, a key summer home for the southern resident killer whales, a distinct population with a unique language and culture. This population currently comprises a small number of individuals, highlighting the fragility of highly specialized marine mammals in a busy maritime region.

Fieldwork and a conservation canine

Researcher Deborah Giles leads a field effort in collaboration with the team, and Eva the terrier mix works as a conservation canine, trained to sniff whale poop to locate samples for analysis. Eva’s role enables Giles to track a highly mobile population at a safer distance while gathering lab-ready material for diet, stress, and reproductive indicators.

"Eva guides Giles straight to the whale poop so that she can collect it" — Deborah Giles

Biology, culture, and dependence on salmon

The southern residents are a non‑breedingly interlinked population with its own vocalizations and social structure. Their diet centers on Chinook salmon, which have declined due to habitat loss, damming, and overfishing, linking the whales’ fortunes to broad-scale fishery management and river restoration efforts.

The three threats and the salmon connection

Researchers identify three major threats: vessel noise, chemical pollution, and lack of prey. Increased boat traffic in the Salish Sea raises ambient noise, impairing communication and foraging, while pollutants accumulate through the food chain, potentially affecting reproduction and health. Salmon population declines compound these pressures, as Chinook salmon are the orcas’ primary prey and are themselves stressed by habitat degradation and human activity.

Funding, policy, and the conservation outlook

The piece also covers how shifting federal priorities in the 2020s have created funding uncertainty for endangered species work. Grants are sometimes returned unread, and budgets for NOAA and related agencies face volatility, complicating collaboration and long‑term planning. Lynn Barry, who led southern resident recovery for two decades, has retired early, citing the administration’s unclear commitment to conservation science as a factor in her decision.

Where to learn more

The episode points to a January feature story and a forthcoming documentary that deepen the understanding of Giles’s research and the ongoing recovery efforts for these iconic whales.

“There’s only 74 of them left.” — Deborah Giles