Mystery orcas return to Seattle area

The mystery orcas are back in town.

A trio of unidentified orcas, never observed in the Pacific Northwest before, showed up in early March, first in Canada’s Vancouver Harbour, then in the busy ports of Seattle, Tacoma, and Olympia.

Where they hail from is still unknown, though researchers determined these mammal-eating, transient orcas had been seen once before, in Anchorage, Alaska. Unusual, cookie-shaped scars indicated they had also spent time in the deep, warm seas favored by the micro-predators known as a cookie-cutter sharks.

The mystery trio showed up again Thursday morning, cruising along the downtown Seattle waterfront in Elliott Bay and the mouth of the Duwamish Waterway, beneath the giant cranes and cargo ships of the Port of Seattle’s Harbor Island.

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The wild predators did not shy away from even the most industrial waters in their apparent hunt for seals and sea lions. The trio, believed to be a mother and her two sons, mostly hugged the King County shoreline as they headed to Tacoma’s heavily industrialized Commencement Bay.

Observers with the Orca Network reported the orcas heading into Tacoma’s Thea Foss Waterway, past the massive Temco grain elevators and a Silver Cloud Hotel, before swimming toward Gig Harbor and Vashon Island.

On Friday, other whale watchers spotted the trio near Bremerton and Bainbridge Island.

A small National Oceanographic and Atmospheric Administration research boat tagged along Thursday to get photos and possibly DNA to help unravel the mystery of these unusual visitors.

NOAA researcher Brad Hanson held an air rifle as he stood in the bow of the inflatable boat, hoping to get a biopsy — a tiny plug of skin and blubber — to reveal the orcas’ genetics and exposure to long-lasting pollutants like PCBs.

In an email, Hanson called it "a unique opportunity without a lot of investment to get info on relatively rare killer whales."

“We weren’t able to get a biopsy nor did we get any recordings as the whales only appeared to hunt once with no obvious kill,” Hanson said.

Unlike the region’s endangered southern resident killer whales, which hunt by emitting sounds to echolocate salmon in the inky depths, transient orcas hunt their mammalian prey silently. They are unlikely to vocalize until after they have had a kill.

The team was able to get photographs and pump up seawater the whales had just swum through to obtain traces of environmental DNA or “eDNA.” The tidbits of floating genetic material can reveal animals' presence, genetics, and diets when biopsies are not practical.

The scientists tracked the orca trio for about two and a half hours, from the Fauntleroy ferry dock in West Seattle to Three Tree Point in Burien, with whales occasionally surfacing next to them.

Researchers have federal permits to approach closer than the buffer zones mandated by state and federal laws.

All other vessels are required to stay at least 200 yards away from the transient orcas and 1,000 yards away from the endangered southern residents.