Ship strike likely killed beached young fin whale

MENDOCINO CO., 9/17/24 — A team of researchers armed with long knives, scalpels, and other surgical instruments descended on 10 Mile Beach north of Fort Bragg Monday. A juvenile female fin whale, measuring 40 feet in length, had washed up on the beach. Before the team from the Marine Mammal Center in Marin County began its cutting and measuring and sampling, intestines were seen 30 yards south of the carcass while blubber was found 30 yards north. She was likely killed when hit by a ship, the leading unnatural cause of death among fin whales.

“The preliminary cause of death for this whale is ship-strike blunt force trauma. She was in excellent body condition and had no evidence of preexisting illness,” said veterinarian Pádraig Duignan, director of pathology at the Marine Mammal Center. 

Fin whales can live more than 100 years and aren’t fully mature until age 25 or more. They are the second largest animal on earth, following their distant cousin the blue whale.

The carcass had much to teach scientists, The Marine Mammal Center team conducted a full necropsy, working in ankle-splashing water in the early afternoon and on the beach until dark, as the tide continued to go out. One scientist said this was a once-in-a-lifetime opportunity to study a recently deceased great whale. The carcass had not begun to stink but horrid smells emerged as they opened up the dead mammal. Volunteers from the Noyo Center for Marine Science helped with the fast-paced study, with some people cutting and others taking pictures or sampling.

The word was soon out on social media, and people arrived throughout the day to photograph the scene. Several set up chairs on the bluffs to watch the fascinating work. On another bluff, eight vultures in a row watched, waiting their turn, while others circled above.

Some were horrified by the sight. Scott Taubold of Fort Bragg came upon the necropsy during his morning bike ride. He went home sad, saying he couldn’t even bring himself to take a photo of the dead whale and the researchers.

Whales stay with their mother for up to two years. Although this whale was barely bigger than a “toddler”-aged fin whale, consider this whale more like a teenager. “She was a juvenile animal and not likely dependent on her mother any longer,” Duignan said.

Much has been learned in recent years about fin whales, which were hunted from estimated highs near a half million individuals down to less than a fifteenth of that total, with numbers remaining high only in the Southern Ocean. They migrate toward both poles in the summer and toward the equator in winter. They tend to group in mid-ocean breeding grounds, a behavior that is still being studied. Scientists have found that trimmer male fin whales sometimes outswim heavier blue whales and breed with female blues in the breeding season, creating a hybrid species.

Their songs have become a scientific sensation in recent years with many trying to understand single-note repeating articulations. They and blue whales make the lowest frequency sound of any animal on earth.  Full-blood fin whales can be distinguished by their dorsal fin (hence the name), which is shared by their only other cousin, Bryde’s whales, which are not found off California. Their most obvious feature is their two-color body and head, with alternating patterns of gray and white. Scientists were cutting and bagging the uniquely dazzling white baleen on Monday afternoon. 

The fin whale is listed as endangered under the Endangered Species Act and depleted under the Marine Mammal Protection Act. This is primarily because of the low population numbers in the Atlantic Ocean off the eastern United States, where it has been intensively studied. The population numbers have not been studied as much off the West Coast, where it is believed to be doing better.

The fin whale population today is estimated to be 14,620 to 18,630 in the North Pacific; 3,590 to 6,300 in the western North Atlantic; 10,500 in the eastern North Atlantic; and 85,200 in the Southern Ocean. Fin whales’ habit of mass feeding on krill in the Southern Ocean has created conflicts with the fishing industry. Japan announced this summer that its whalers plan to hunt fin whales again in the Southern Ocean, creating outrage in the world environmental community. Greenpeace activists on ships battled Japanese whalers for decades, in addition to whalers from Norway and Iceland, the only other two countries still whaling. Whaling caused many whale species to go extinct and all others to be pushed to the brink before whaling began to be heavily regulated in 1946 until almost all whaling stopped in 1986.

Ship strikes are the number one cause of fin whale premature deaths worldwide, according to scientific studies. Fin whales are uncommonly seen along the Mendocino Coast, while gray whales create an annual show in March and December as they wend their way back and forth from their Baja breeding grounds to their Arctic feeding grounds. No other whale species have predictable or near-shore routes. Gray whales top out at about 40 feet, the size of the young fin whale that washed up. Fin whales can reach 80 feet when mature. Blue whales can occasionally be seen, along with more common but unpredictable humpback whale sightings. Before 2005, there were rumors of orcas but no confirmed sightings. Then an orca pod started taking regular trips south, and orcas are seen every year by a few lucky people who happen to be looking when that one tribe of killer whales is passing. A sperm whale, the third largest whale, washed up on the Mendocino Coast two years ago. Sperm whales, the only predator whale among the great whales, are very rare in this part of the world.

The Marine Mammal Center usually sends out teams when marine mammals are alive but stressed or beached. Seals and otters are taken to their headquarters in Marin County for veterinary care. Assistance in getting back into the water is sometimes rendered for larger animals such as sea lions. Since 1975, the center has rescued more than 24,000 marine mammals along 600 miles of California coastline and the Big Island of Hawaii, according to its website. With a volunteer force numbering more than 1,400 and a strong donor base, the center is able to respond to marine mammals in distress. 

Duignan said he had heard of another young fin whale washing up this year in Southern California. “The Marine Mammal Center  has been doing whale necropsy response for almost 50 years so we have definitely done fin and blue necropsies before,” Duignan added. The scientists left little of the whale behind, but people continued to come to the beach until dark on Tuesday. It is a federal crime to remove the body parts of an endangered species.

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