Researchers say a humpback whale that was struck by a ship and washed ashore Aug. 28 in Half Moon Bay was a well-known humpback named Fran.

Scientists at the Marine Mammal Center in the Marin Headlands and their partners at whale data organization Happywhale confirmed Fran’s death Monday during a necropsy. The official cause was blunt force trauma.

The Happywhale database has recorded 277 sightings of Fran since her 2005 birth, making her the most popular whale in California. Most of those sightings came in the Monterey Bay area.

“The death of Fran is incredibly tragic, given that ship strikes on whales can be avoided,” Kathi George, the director of field operations and response at the Marine Mammal Center, said in a statement. “Everyone, including shipping companies, wants to protect these magnificent giants, and we need ships to slow down in vessel speed reduction (VSR) areas as well as when whales are around.”

“Our team at Happywhale tracks individual whales in the North Pacific through automated image recognition AI to better understand and protect whales and their ocean environment,” said Ted Cheeseman, the founder of Happywhale. “We know that Fran has been photographed all but one year since she was born. Learning of her death is especially sad since this year marks the first year she’s successfully brought a calf to feeding grounds.”

Fran was most recently seen in July in Monterey Bay with her healthy calf.

Researchers said during a Wednesday morning news conference there were signs on Fran’s body she hadn’t nursed recently, giving them hope her calf is already eating on its own and will survive.

The necropsy showed that the ship impact detached Fran’s skull from her spine, indicating not only that the ship was traveling at a high speed, but that Fran likely died quickly.

Fran was part of what researchers called the Mexican population of humpbacks. She had previously been tagged with some technology to help scientists learn more about the species.

“We had more data on her than mostly any other whale,” said John Calambokidis, co-founder and senior research biologist at the nonprofit Cascadia Research. “She was quite a contributor to science in life, as well as now in death.”

Speed kills

According to the Happywhale database, Fran was born in 2005 and was the daughter of Big Fin, aka River, and was named by Ferd Bergholz in honor of his late wife. Fran often wintered in Guerrero, Mexico.

Officials said deadly ship strikes can be prevented by ships reducing speed in known whale habitats. The National Oceanic and Atmospheric Administration (NOAA) issues seasonal speed reduction requests within its West Coast national sanctuaries to reduce the risk of fatal strikes to whales, including endangered blue, fin and humpback whales.

The NOAA said in a statement more than 60 percent of ships reduce their speed in these seasonal zones, but “we need to increase that percentage and take additional measures to avoid more deaths like Fran.”

“This is one of those things that was out of sight, out of mind,” Cheeseman said. “If the public saw these (collisions), they wouldn’t happen.”

George said ship strikes kill up to 80 whales a year on the West Coast.

A humpback whale later identified as “Fran” lies on Manhattan Beach in Half Moon Bay prior to a necropsy that confirmed the cause of her death. Ship strikes kill approximately 80 whales on the West Coast each year, according to the Marine Mammal Center. (Photo by Padraig Duignan/Marine Mammal Center via Bay City News)

“The numbers that are reported are not the numbers that occur,” George said. “Most of these whales sink. Only 5 percent wash up onto the shore.”

Jennifer Stock, the media liaison for Greater Farallones and Cordell Bank national marine sanctuaries, said her group’s advisory councils have formed a Joint Ship Strike Working Group to evaluate management options and provide feedback on risk reduction.

Among potential remedies for ship strikes include mandatory speed limits and possibly moving shipping lanes.

The primary goal of the sanctuary ship strike work is to reduce the risk of lethal ship strikes to endangered and threatened blue, humpback, and fin whales by 50 percent in West Coast national marine sanctuaries.

Humpback whales frequent the California coast to feed during the summer and fall months before migrating south to their winter calving and mating grounds off the coast of Mexico.

To report a dead whale or whale in distress, call the Marine Mammal Center’s rescue hotline at 415-289-SEAL (7325). All marine mammals are federally protected, and the public should not approach any whale, alive or dead.