San Francisco residents discovered the fifth dead grey whale in the bay, less than a month after the first four animals’ carcasses were found.

Witnesses discovered the dead body of the animal on Friday near Fort Funston. Authorities have not yet determined a cause of death of the creature.

Dead Gray Whales

Experts said April is when the whales begin their migration to the northern regions. This made it common to find dead whales near San Francisco Bay. However, they were concerned with the frequency of the recent incidents, where four animals were found in just nine days.

“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,” the Director of Pathology at The Marine Mammal Center, Dr. Padraig Duignan, said.

The first of the dead animals was discovered at the Crissy Field on March 31. The second whale was found in San Mateo County’s Moss Beach on April 3. Residents discovered the third creature on April 7 near the Berkeley Marina. The fourth was found near Muir Beach in Marin County.

There were at least 13 dead whales spotted in the Bay Area in 2019. Scientists expressed their worries the incidents were due to starvation during their Mexico to Alaska migration. Biologists have studied the creatures and found their bodies in poor conditions. Since then, the National Oceanic and Atmospheric Administration declared an “unusual mortality event,” KTLA reported.

In recent years, the most common causes of death of the whales were malnutrition, entanglement in fishing gear, and trauma from ship strikes. Experts conducted a necropsy of the dead animal found at Muir Beach. They discovered it had severe bruising and hemorrhaging to muscle around its jaw and neck vertebrae.