We Now Know What Killed the Whale Found in the Port of Tacoma

When a massive fin whale unexpectedly arrived in the Port of Tacoma on the bow of a cargo ship Monday morning, one of the biggest questions was whether the ship had killed the animal — or simply encountered a whale that was already dead.

Researchers now have an answer.

The approximately 67-foot female fin whale was alive and apparently healthy when she was struck by a vessel. The collision killed her.

That conclusion comes after a team of researchers conducted a necropsy Wednesday on McNeil Island, where the carcass had been towed after being removed from the bow of the Evergreen Marine container ship that carried it into Tacoma.

The finding adds an unfortunate final chapter to a story that drew considerable attention around Tacoma earlier this week.

Perhaps the most significant discovery from the examination was what researchers didn't find.

The whale wasn't malnourished or obviously suffering from an underlying condition before the collision.

Researchers found a healthy layer of blubber and high oil content, both signs that the whale had been feeding successfully and was in good physical condition. She was described as being in the prime of her life.

Researchers couldn't determine whether she was pregnant or exactly how old she was, although she was an adult and among the larger fin whales recently encountered in the northeastern Pacific.

That evidence allowed researchers to rule out one of the possibilities surrounding the whale's death: that she had died from another cause before becoming lodged on the ship.

Instead, evidence from the necropsy showed that the vessel strike occurred while the animal was still alive.

One mystery remains: where the collision happened.

The container ship had traveled from China and may have encountered the whale near Alaska's Aleutian Islands or somewhere along the North Pacific portion of its journey.

By the time the whale reached Tacoma, researchers estimated that the carcass was moderately decomposed.

The ship's crew also may have had no idea a collision occurred.

Fin whales have long, relatively slender bodies that can become caught on the bulbous bow of a large ship. Researchers say vessels sometimes carry whales considerable distances before anyone realizes an animal is there.

That appears to be what happened here.

The ship arrived at the Port of Tacoma at about 5 a.m. Monday with the whale lodged across its bow, creating the striking images that circulated around Tacoma and the region.

Fin whales are the second-largest whale species on Earth, behind only blue whales. Despite their enormous size, however, they're vulnerable when their habitat overlaps with major shipping routes.

NOAA Fisheries identifies vessel strikes as one of the primary threats facing large whales on the West Coast. Fin, blue, humpback and gray whales are considered particularly vulnerable because they migrate and feed in areas that also carry heavy commercial vessel traffic.

Nighttime may make the problem worse.

Research discussed following the Tacoma necropsy indicates that fin whales spend much of the night near the surface. During daylight hours, they spend more time diving into deeper water.

That combination can put a surfacing whale directly in the path of a ship at the same time visibility from the vessel is at its worst. Researchers estimated whales in their study were about twice as likely to be struck at night as during the day.

For the crew of a massive container ship, avoiding such a collision can be extraordinarily difficult. A whale surfacing in darkness ahead of a vessel may be nearly impossible to spot in enough time to maneuver a large ship away from it.

Scientists are exploring technology that could help. NOAA is currently working with partners on systems using thermal cameras, radar and artificial intelligence to detect whales and reduce the risk of vessel strikes.

Other approaches include slowing vessels in areas where whales congregate and moving shipping lanes away from whale-dense waters.

After Wednesday's necropsy, the whale's carcass was expected to remain at the McNeil Island site and decompose naturally, allowing its nutrients to return to the surrounding ecosystem.

Researchers will continue analyzing information gathered during the examination to better understand the collision and ways similar deaths might be prevented.

Fin whales remain federally endangered, a legacy of the commercial whaling era that dramatically reduced their population. Their numbers have recovered substantially since commercial hunting ended, but ship strikes remain a continuing threat.

And researchers caution that the collisions we know about may represent only a fraction of those that actually occur.

Whales killed offshore often sink without ever being discovered. In this case, the unusual circumstance of the animal becoming lodged on a container ship and being carried all the way into the Port of Tacoma gave scientists an opportunity they rarely receive: the chance to examine the animal and determine exactly what happened.

For Tacoma residents who followed the whale's unexpected arrival earlier this week, there is now an sad answer.

She was a healthy whale. A collision with a ship killed her.