The big problem for endangered orcas? Inbreeding

SEATTLE (AP) — People have taken many steps in recent decades to help the Pacific Northwest’s endangered killer whales, which have long suffered from starvation, pollution and the legacy of having many of their number captured for display in marine parks.

They’ve breached dikes and removed dams to create wetland habitat for Chinook salmon, the orcas’ most important food. They’ve limited commercial fishing to try to ensure prey for the whales. They’ve made boats slow down and keep farther away from the animals to reduce their stress and to quiet the waters so they can better hunt.

So far, those...