Visitor finds decapitated sea lions on California beach, discovery not as sinister as she thought

DALY CITY, Calif. (KTVU) - Katie Harrison was taking a weekend walk along Mussel Rock Park Beach in Daly City when the sight of decapitated sea lions and a man walking around with a hunting knife sent her into "a state of terror." 

“I see this guy carrying a knife mutilating sea lions, and I was afraid to go to my car. I felt trapped on the beach. It was horrific,'' the 35-year-old flight attendant said. 

Harrison called police but said she said when they arrived to meet her in the parking lot, they didn't seem too worried and didn't investigate too deeply. 

If they had, they would have found out that what Harrison stumbled upon late last month was part of a federally sanctioned, legitimate and important, scientific endeavor conducted by the California Academy of Sciences in San Francisco. 

Each year, scientists fan out on beaches to collect samples from dead sea lions and fur seals that wash up along the shorelines, attempting to figure out how they lived their lives and how they died.

The academy’s Department of Ornithology and Mammalogy is a participant in the Marine Mammal Stranding Network, a federal research program run by the National Marine Fisheries Service. 

Senior Collections Manager of Birds and Mammals Moe Flannery said the scientist that day was taking off the heads of already dead sea lions, as well as “disarticulating” the penis bones of the male mammals in order to bring back to the academy’s renowned library. 

Skulls in particular can tell an animal’s place in the ecosystem, and the location of eye sockets is one of the best indicators of whether it was prey or predator, according to academy scientists.

Teeth, jaws, and other skull features can provide clues about what an animal ate, how it captured and consumed meals, and its state of health when it died. Plus, skulls can tell a scientist how old the mammal was, Flannery said.

Academy scientists collect the baculum, or the penis bone, of male sea lions as scientific evidence of the gender of the mammal, she added.

The sea lions are left on the beach, scientists said, so they can naturally decompose, which in turn provides an important food source for  birds, mammals, and invertebrates in the area. 

In past years, scientists have discovered that sea lions were dying from an aggressive cancer likely caused by a sexually transmitted virus.  In some instances,  a massive bloom of the algae produced domoic acid, a toxin that concentrates in top predators like sea lions, causing seizures and brain damage.

And in other cases, the stressed ecosystem had made it hard for females to find enough food to produce milk for their pups, who may strike out on their own too soon and land on shore, starving and emaciated.

The reason for why the sea lions on Mussel Rock Beach died, has yet to be determined, Flannery said.

Flannery said sea lion and seal deaths are more common between June and August in California, as that’s when the young leave their colonies and swim out on their own. How many sea lions have died this year, hasn't yet been tallied. But the typical amount of deaths Flannery's team sees in the academy’s jurisdiction of Northern California is about 300 a year. 

Harrison didn't know any of this when she sent her queries and pictures to KTVU in the hopes of trying to figure out what was going on. 

When she was told of the research, the Brisbane woman aid she’s fine with the scientific exploits. It’s just that there was no notification or warning for her or other beach goers. She said she’s gone to other beaches where there are signs, or yellow tape cordoning off the animals. She said she didn’t stop to talk to the scientist because she feared for her life. She said she did not see any identification on the man, though it may have been covered by his clothes. 

“The way they're going about it just seems grotesque and unprofessional,” she said. 

Sea lions have been wrongly slain in recent years. Last year, a mystery mammal murderer neat Seattle had killed about a dozen sea lions, which were found with bullets or shotgun pellets lodged in their heads. 

Flannery said she hasn’t heard from any other worried beach goers in the recent past. But over the years, the academy has had occasionally calls when the late Roy “Bones” Bandar used to collect skulls as a volunteer ambassador for more than 50 years. Bandar died last year at age 90, and other scientists the academy have taken over for him. 

Flannery said the academy does not put up signs or cordon off parts of the beach because they don't want to leave anything behind that might become litter. Researchers also don’t call police to notify them that they are going out. To identify the mammals that are part of the study, Flannery said that the scientists wrap a piece of white or green bio-degradable twine around sea lions’ flippers.

If beach goers want to know if the decapitation is the act of a scientist, or an unsanctioned poacher, they can take a picture and send it to marinemammals@calacademy.org to find out.