Another dead whale was just found in San Francisco Bay — the fifth in under a month

A fifth dead whale has been discovered in San Francisco Bay in less than a month.

The whale was found Friday near Fort Funston, The Associated Press reported. The cause of death hasn’t been determined yet.

A few gray whales are usually found dead in or near the bay each year as the marine mammals migrate along the California coast, experts said.

But Giancarlo Rulli of the Marine Mammal Center said it is “so critical” to figure out what’s behind this recent “unusual” spate of dead whales.

“This is an unusual mortality event for gray whales,” he told SFGate. “We’ve seen increasing numbers of dead whales wash ashore over the last two years.”

Eric Jones, founder of the organization Sea Valor, added to KTVU: “these creatures, they are such magnificent creatures and to see them dead like this is really heartbreaking.” His organization helped tow one of the dead whales to Angel Island for examination.

A 41-foot adult female gray whale washed up at Crissy Field on March 31, the Marine Mammal Center reported. A necropsy, or animal autopsy, failed to determine the cause of death.

A second whale was found April 3 in Moss Beach and a third was found near the Berkeley Marina on April 7, according to The Los Angeles Times. A fourth whale washed up on Muir beach a day after the third whale.

Malnutrition or accidents involving ship collisions or fishing nets are often found to be causes of death for gray whales, the Marine Mammal Center said.

But the whale found at Crissy Field showed no signs of illness or trauma, experts said.

California gray whales, which can reach 39 feet long and weigh 60,000 pounds, are on their yearly 11,000-mile trek north from Mexico to Alaska.

Four dead whales found in San Francisco Bay puzzle experts. ‘Really heartbreaking’