07/31/2026
Just after this week's southern resident orca census news, here's another look at these endangered whales — this time, after dark.
"There's no rest for these endangered whales. They are attempting to find food day and night."
That's NOAA Fisheries Service biologist Marla Holt, describing new research that offers the first published look at what southern resident killer whales do after dark. Researchers attached acoustic recording tags to 10 whales and found they're diving and hunting almost as much at night as during the day.
But not evenly. Females are far less likely to attempt a catch at night than during the day, and the drop-off is stark: on deep dives, females had an 88% probability of attempting a catch during the day, but just 21% at night. The findings add to earlier evidence that vessel noise disrupts female foraging more than males' during the day, reinforcing the case for measures that reduce daytime vessel traffic noise in the Salish Sea.
Full story, video of a tagging in action, and audio of orca echolocation clicks: https://tinyurl.com/orcasatnight