FRIDAY HARBOR, Wash. -- Researchers studying droplets emitted from orca blow holes have found drug-resistant bacteria.

They could be a sign of pollution and a risk to the killer whale population in Puget Sound, which is apparently in decline.

The Kitsap Sun says the independent research by biologist David Bain and veterinarian Pete Schroeder was presented at a Tuesday meeting in Friday Harbor on orca health.

Schroeder says the bacteria may come from human sources such as untreated sewage or stormwater.

Seven Puget Sound orcas are missing and presumed dead, bringing the population to 83, the fewest in five years.