SAN FRANCISCO (CBS SF) — One of four whales that washed up dead in the Bay Area since last Wednesday was killed by a ship strike, according to scientists with the Marine Mammal Center.

The whale carcass, a 41-foot adult female, washed ashore at Muir Beach Thursday afternoon. The cause of death of the other whales has not yet been determined.

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“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,” said Dr. Pádraig Duignan, Director of Pathology at The Marine Mammal Center in a prepared statement. “These necropsies are critical to provide insights into gray whale population health and that of their ocean home, including how human activity impacts them.”

One whale carcass found near the Berkeley Marina on Wednesday. The other two were discovered at Crissy Field in San Francisco on March 31 and at Fitzgerald Marine Reserve on the San Mateo County coast on Saturday.

A necropsy on the whale found at Crissy Field did not determine a cause of death, the Marine Mammal Center said.

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During the necropsy at Muir Beach, scientists found injuries to the whale’s jaw and neck vertebrae consistent with blunt force trauma due to ship strike, the Marine Mammal Center said, noting the whale was in good body condition based on the blubber layer and internal fat levels.

Malnutrition, entanglement, and trauma from ship strikes have been the most common causes of death found by the Center’s research team in recent years, according to the Marine Mammal Center. Biologists have observed gray whales in poor body condition during their annual migration since 2019.

Increased numbers of gray whales have since been sighted in the San Francisco Bay as the population continues their northerly migration to cool, food-rich Arctic waters, the center said, adding that climate change and overfishing have led to reduced prey availability for whales.

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