Gray whale found dead near Pier 80 in San Francisco, vessel strike suspected

A gray whale found in San Francisco Bay last week is believed to have been killed in a vessel strike, scientists said Thursday.

The Marine Mammal Center in Sausalito told CBS News Bay Area that an adult male whale was found floating off San Francisco's Pier 80 on the morning of June 4. On June 5, the center's Cetacean Conservation Biology Team saw the whale carcass floating southeast of Alcatraz.

The U.S. Army Corps of Engineers towed and secured the 38-foot whale, bringing the carcass to Sand Springs Beach at Angel Island State Park.

A team of scientists from the center and the California Academy of Sciences performed a necropsy on Sunday. Scientists noticed evidence of blunt force trauma, including hemorrhage behind the skull and a broken vertebra "consistent with blunt force trauma due to a suspected vessel strike."

The whale was in "fair to normal body condition" at this point in the migratory season, the center said. Additional samples were taken for further testing.

According to the center, this case marks the 13th dead gray whale found in the wider Bay Area so far this year.

The cause of death in four of the incidents have been determined as suspected or probable vessel strikes, including a whale that was found off San Leandro on May 27 and a whale that was found in San Francisco Bay on March 17.

The center said gray whales are currently on their northern migration to their feeding grounds in the Arctic. Several whales frequenting San Francisco Bay are expected to depart in the next two weeks.

According to a population estimate by the NOAA Southwest Fisheries Science Center, there are about 12,900 North Pacific gray whales, the lowest since the early 1970s.