(CNN)A dead gray whale washed ashore on a San Francisco beach Monday morning -- the ninth such death in the Bay Area this year, scientists at the Marine Mammal Center said.
Nine dead gray whales have washed ashore in the San Francisco Bay Area this year
"The death of nine gray whales in the San Francisco Bay Area this year is a cause for serious concern and reinforces the need to continue to perform and share the results of these type of investigations with key decision-makers," Dr. Padraig Duignan, Chief Research Pathologist at the center, said.
A necropsy will be performed on the whale Tuesday, the Marine Mammal Center said.
Blunt force trauma from ships, malnutrition and entanglements are the most common causes of death in whales, the center said. Necropsies have confirmed the cause of seven of the previous eight whale deaths this year. Three whales died from ship strikes and four from malnutrition. The cause of death of the eighth whale has not been determined.
"It is critical for scientists to conduct in-depth necropsies to better understand why animals are dying," the center said in a news release.
"Whales and other marine mammals face numerous human-caused threats and solutions must be found to protect healthy and vulnerable species alike," the center said.
Today, there are about 26,000 gray whales, found only in the Pacific Ocean, according to the center. There are more gray whales around the San Francisco area than usual this time of year, as they migrate north.
The center says biologists have observed gray whales "in poor body condition" this year, possibly "due to anomalous oceanic conditions" which have contributed to "shifting food sources."
The 90,000-pound creatures were once on the brink of extinction.
In the late 1800s and again in the early 1900s, the gray whale population dropped to less than 2,000 after they had been hunted by humans.
In 1946, an international agreement to stop hunting them helped put their numbers back on track and in 1994 they were taken off the Endangered Species List.