Humpback whale swimming in San Francisco Bay has experts worried

A humpback whale who has made its home in California's San Francisco Bay for the past two weeks appears to be in poor health, experts said.

The adult cetacean, which whale watchers have nicknamed “Allie,” looks to be underweight. It also has poor skin condition, including a "moderate amount of whale lice," officials at the Marine Mammal Center said.

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“This one was in poor health and came into a very protected area of water in the bay,” Bill Keener, an associate with the new cetacean field research program, told the San Francisco Chronicle. “Whether it came in to feed or to rest, we don’t know. Its skin condition was rough and degraded, indicating it was in poor health.”

Biologists believe Allie entered the bay searching for shelter from the harsh open ocean. (Bill Keener/Marine Mammal Center via AP)

Biologists believe Allie entered the bay searching for shelter from the harsh open ocean. (Bill Keener/Marine Mammal Center via AP)

The sickly-looking whale’s appearance comes amid a special government investigation into the deaths of over 75 gray whales that have washed ashore along the West Coast in recent months. While many of those whales appeared abnormally thin and weak, experts told the Chronicle it is likely unrelated to Allie’s unusual presence in Alameda.

Biologists believe Allie entered the bay searching for shelter from the harsh open ocean. Officials also said that humpbacks feed near the Golden Gate Bridge, where the waters can be rich with anchovies. But the animals rarely travel deep into the bay, like Allie.

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Biologists assessed the whale, but found no external injuries, The Guardian reported. Officials said they were unable to determine the leviathan’s age and sex.

The humpback has remained in the waters near Alameda for more than two weeks. (Bill Keener/Marine Mammal Center via AP)

The humpback has remained in the waters near Alameda for more than two weeks. (Bill Keener/Marine Mammal Center via AP)

John Calambokidis, a senior research biologist for the nonprofit Cascadia Research Collective, told the Chronicle that whales have made an extraordinary comeback from near-extinction. About 20,000 humpbacks now inhabit the region. The population surge may account for spotting whales in new areas, he said.

Meanwhile, Allie hasn’t been seen in the San Francisco Bay for a couple of days. Keener told The Guardian it may have found its way back out to sea.

During Allie’s extended stay in the bay it gained an intense public interest from whale enthusiasts, who even set up a Facebook page for the giant mammal.

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The Associated Press contributed to this report.