Rare, Little Understood Whale Stranded Near Santa Cruz

On the afternoon of May 31, UC Santa Cruz physiological ecologist Robin Dunkin got a call about a whale stranded out at Scott Creek Beach, near Davenport. She and a number of colleagues from the Marine Mammal Stranding Network drove straight to the beach. To their surprise, the mammal in question was a Hubbs’ beaked whale (Mesoplodon carlhubbsi), a very rare and poorly understood marine mammal species.

“We got out to the beach. The animal was rolling in the surf, but it was clearly still alive,” said Dunkin, who directs the UC Santa Cruz Long Marine Lab Marine Mammal Stranding Network. The team also included UCSC campus veterinarian David Casper.

Scientists and volunteers were able to get a rope around the animal’s fluke, and as the tide came in, they were able to pull the 8.75-foot-long, 500-pound whale onto the sand. They sat back in awe. “There was concern for the animal,” said Dunkin, but “there was also the feeling of adrenaline when you are dealing with something that is so big and rare, and you are trying to give the animal the best care possible.”

Once it was on the sand, Casper assessed the animal and took its vitals. The whale appeared to have an injured snout; its lower and upper jawbones were broken, which would prevent it from feeding. Casper called a team of experts at the Marine Mammal Center to see if it was a candidate for rehabilitation. But there was no way to care for the whale in an existing rehab center.

“This animal is a deep-water species and had a massive traumatic injury. It would have been inhumane to try and rehabilitate it,” said Dunkin. The whale had to be euthanized on the beach and was transported to Long Marine Lab in a van.

Necropsy Results

The next step was to understand why the whale had died, if possible. At the lab, Dunkin and Melissa Miller, a veterinary pathologist at the California Department of Fish and Wildlife, performed a necropsy, collecting hundreds of tissue samples to be shared with researchers around the world. The whale’s brain was sent to a neurology lab in New York to better understand how sonar’s disruptive signals harm whales.

The post-mortem revealed traumatic injuries to the beak or snout of the whale, also known as the rostrum, which had subsequently become infected. The scientists thought the whale had most likely become injured in the course of interacting with other animals or when hunting. Beaked whales are pelagic species that hunt deep in the ocean where there is no light, relying on sonar. This particular whale might have crashed into a rock when chasing prey, Dunkin said.

An Elusive, Deep-Diving Whale

Given how rare this species is, scientists were working to verify that they had identified it correctly. In fact, they initially misidentified it. “We looked at an identification key — it did not fit the profiles of any of the whales we have ever had,”  said Dunkin. “But it did fit the morphological features of a Perrin’s beaked whale.”

Dunkin sent DNA samples to the NOAA Southwest Fisheries Science Center for genetic confirmation.

“Well, surprise surprise — the genetics came back and told us that the whale is actually a Hubbs’ beaked whale,” said Dunkin. She explained that the morphology (physical features) of a juvenile Hubbs’ whale looks just like a Perrin’s beaked whale.

The beaked whale’s skeleton will be going to the California Academy of Sciences.

In general, beaked whales spend about 98% of their time deep below the ocean’s surface, and because of their elusive habits, they seldom come into contact with humans. “There are lots of mysteries still out there, and what’s rare is getting the chance to be able to look one of these very mysterious animals in the eye and really learn something about it,” Dunkin said.

Beaked whales are the deepest-diving cetaceans, regularly descending to depths lower than 3,300 feet. They are suction feeders: By opening their mouths very quickly, they create a vacuum where water rushes in, pulling in prey like squid, Dunkin said.

We don’t know much about Hubbs’ beaked whales. Fewer than 60 specimens have come to scientists’ attention after the first ones started washing up on beaches in 1944, and only one was spotted alive in its Pacific Ocean habitat. The Hubbs’ beaked whale gained status as a new species in 1963. Past specimens have been stranded along the West Coast and Japan.

A Tough Summer

It’s already been a tough summer for whale strandings. So far, 70 whales have washed up on California beaches, for a variety of reasons. So it’s been a busy time for the Long Marine Lab Marine Mammal Stranding Network, one of several organizations that operates year-round to respond to live and dead marine mammals that wash up on shore. Others include the Moss Landing Marine Laboratories and the Marine Mammal Center in Sausalito.

If you see a sick, injured, stranded or dead marine mammal or sea turtle call your local stranding network. You can also use the Dolphin and Whale 911 app to report a stranded marine mammal. The app is available for Android devices as well as iOS.