Whale Killed by Ship Fifth To Wash Up in San Francisco Waters in a Month

An endangered whale that washed up on a San Francisco shore last week probably died after being hit by a ship, researchers have concluded. It was the fifth whale death in the area in the past month.

The dead fin whale was first spotted at sea on Friday, April 23, by the U.S. Coast Guard. It landed near Fort Funston later that evening.

The cause of death was not immediately clear, but researchers from The Marine Mammal Center at the California Academy of Sciences and U.C. Santa Cruz said over the weekend the animal had suffered trauma to the neck, including bruising and bleeding to the muscle surrounding neck vertebrae, according to CBS Local.

Barbie Halaska, necropsy manager for The Marine Mammal Center, said in a statement: "Ship strikes are the biggest threat fin whales face, so this investigation helps us understand the challenges these animals face and inform decision-makers so we can safely share the ocean with marine wildlife."

Halaska added that by investigating whale deaths, researchers can learn more about how humans are impacting the lives of the animals.

The center has already investigated four other whale deaths around the Bay Area in April alone. All of those four were gray whales.

Dr. Pádraig Duignan, director of pathology at The Marine Mammal Center, said in an earlier press release: "It's alarming to respond to four dead gray whales in just over a week because it really puts into perspective the current challenges faced by this species."

Ship strikes are the number one threat facing the fin whale today, according to the National Oceanic and Atmospheric Administration (NOAA). The species is listed as endangered by the U.S. Endangered Species Act.

The fin whale is the second-largest animal in the world. It can grow to a length of 85 feet, weigh up to 80 tons, and live as long as 90 years. They are often found in social groups of between two and seven individuals.

Their numbers plummeted during the mid-1900s due to whaling as hunters wanted their oil, bone, and fat. Around 725,000 were killed in the southern hemisphere alone during this time.

Today, there are thought to be around 82,000 left in the southern hemisphere, and just 3,200 in the waters off of California, Oregon, and Washington.

The California coast is home to four major shipping ports—San Diego, Long Beach, Los Angeles, and Oakland—but it is also home to important feeding and breeding grounds for several species of large whale.

Some efforts have been made in the past to curb the number of whale strikes, such as adjusting shipping lanes. Deaths still take place, however.

In addition, earlier this year Aarhus University in Denmark reported there had been several sightings of gray whales that appeared emaciated and starving as they migrated south toward California from their feeding grounds further north.

There had also been 378 confirmed gray whale fatalities reported since 2019 in what scientists have called an unusual mortality event (UME). Research has suggested a decline in their survival and reproductive rates during the UME is being caused by starvation.

The cause is unclear, but global warming could have led to a decline in the whales' main food source of amphipods.

Whale researcher by dead whale
Barbie Halaska, necropsy manager with The Marine Mammal Center, with a dead juvenile gray whale on May 25, 2019 in Point Reyes Station, California. California is home to important feeding and breeding grounds for multiple whale species. Justin Sullivan/Getty