Killer whale beaches in Mendocino County, boon for researchers

Researchers dissect and take samples from a killer whale where it washed up on Saturday, April 18, 2015, north of Fort Bragg. Researchers dissect and take samples from a killer whale where it washed up on Saturday, April 18, 2015, north of Fort Bragg. Photo: Courtesy, Sheila Semans, Noyo Center Photo: Courtesy, Sheila Semans, Noyo Center Image 1 of / 8 Caption Close Killer whale beaches in Mendocino County, boon for researchers 1 / 8 Back to Gallery

A killer whale beached itself and died north of Fort Bragg in Mendocino County, a rare occurrence that provided a shocking sight but also a rare opportunity for scientists and students to study the life and death of the big cetacean.

The orca appeared on a beach Saturday morning, said Sheila Semans, who directs the Noyo Center for Marine Science in Fort Bragg, a town of about 7,000 people about 170 miles north of San Francisco.

Necropsy begins

A team of researchers quickly assembled — from the Noyo Center, the Marine Mammal Center in Sausalito, the California Academy of Sciences and Humboldt State University — and performed a necropsy.

They found harbor seals in the whale’s stomach in various states of digestion, meaning he had recently been healthy enough to eat. But the cause of the animal’s death may remain a mystery, Semans said. The orca had a line from a crab pot wrapped around its tail, but that was ruled out as the cause of death.

'Amazing experience’

Still, Semans said, “This really gives us the amazing ability to look at the science behind the life and death of these animals. It was an amazing experience, especially for the students, to get up close and personal with him.”

Part of that experience was the macabre task of cutting the whale into pieces small enough to move off the beach, which took two full days.

After opening up the animal to examine its stomach contents, scientists took tissue samples and X-rays of the bone structure, said Moe Flannery, collections manager for the Department of Ornithology and Mammalogy at the Academy of Sciences.

“It was hard work,” she said, “but this is a unique opportunity for scientists all over the world. The more we learn, the better we can focus our conservation efforts.”

Maggots help out

The whale’s body is being stored in a water treatment facility in Fort Bragg, where Semans said the carcass would be buried in compost to enlist the help of maggots in stripping the bones. Once clean, the skeleton will be reassembled and put on display at the yet-to-be-built Noyo Center.

Nearly every part of the whale will be examined, Flannery said, especially the teeth, which have layers that hold a wealth of information about the whale’s age and diet, much like tree rings.

While orcas are not exactly common off Northern California, transient pods travel up and down the West Coast, Flannery said, and three other killer whales have washed ashore in the Bay Area since 2008.

Not 1st beached whale

The creature’s appearance on Saturday was not Fort Bragg’s first experience with preserving marine mammals for science, either. In 2009, a 73-foot blue whale that was struck by a ship’s propeller washed up there. The Noyo Center, along with members of the community, are working to prepare that skeleton for display.

Last week, a dead sperm whale washed ashore in Pacifica. A cause of death could not be determined.

Kale Williams is a San Francisco Chronicle staff writer. E-mail: kwilliams@sfchronicle.com Twitter: @sfkale