The orca population in Washington’s Puget Sound is dropping, and scientists think a scarce food supply is to blame, the Seattle Post-Intelligencer reports. A poor year for chinook salmon—and another is in the forecast—forced the killer whales to spend energy searching further afield for food. Two mature females (the least likely orcas to die) and five others were lost this year, the biggest yearly decline since the 1990s.
Lack of food may be a catalyst for a more serious threat to the population, which numbers 83, down from 97 in 1995. As the whales starve, they consume body fat much like humans. But fat stores PCBs and other chemicals they might have ingested. PCBs have been shown to interfere with reproduction in dolphins and make seals sick. “Is this directly starvation? Maybe, maybe not,” a marine biologist said. “There might be something else going on.”