BOLINAS (CBS SF) — The carcass of an endangered fin whale, the second in a week, has washed up on a Northern California beach, Marine Mammal Center officials announced Thursday.

The 58-foot female was spotted on the shoreline between Brighton and Agate Beach in Bolinas on Wednesday afternoon.

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“The death of a second female fin whale this week is incredibly unfortunate, particular since fin whales are an endangered species,” says Dr. Shawn Johnson, Director of Veterinary Science at The Marine Mammal Center.

Officials said they were working with the National Oceanic and Atmospheric Administration and California Academy of Sciences to develop a plan to perform a necropsy, or animal autopsy, to determine the cause of death on Friday.

“Whale necropsies are critical to provide insights into the overall health of these animals and their ocean environment, including human activity that can impact them, with the goal of understanding how best to protect these endangered species,” Johnson said.

A third whale — a gray whale — also washed ashore last week. The Marine Mammal Center has responded to six dead whales this year, including four gray whales.

On Wednesday, Marine Mammal Center officials said that the two whales that that washed up in the Bay Area last week died to due to human-related causes.

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The fin whale found near Jack London Square in Oakland on Friday morning died after being struck by a ship, and a gray whale carcass that washed ashore in Marin County later the same day died after being severely entangled.

The fin whale was a 45-foot female juvenile that suffered massive hemorrhaging on both sides after the collision, center officials said. It was towed to Angel Island State Park, where scientists performed a necropsy.

Center officials confirmed the juvenile was the same whale reported to the National Oceanic and Atmospheric Administration on May 16, after it was found draped across the bow of a large ship entering the Bay.

The 36-foot adult female gray whale found at Tennessee Valley Beach in Marin County suffered lesions around the back of her neck and both front flippers. She also had two lacerations on the right side and multiple skull fractures consistent with a ship propeller, according to center officials.

The two cases are unrelated, but ship strikes are the leading cause of whale mortality, followed by fishing gear entanglement, center officials said.

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