SAN FRANCISCO (KPIX) — A beach at Angel Island is the final resting place for two young gray whale corpses.

Last week, a pod of five gray whales made its way into San Francisco Bay, an unusual detour for the migrating marine mammals.

“The biologists are thinking that perhaps it’s an unusual abundance of some kind of food that’s attracting them in here this year — shrimp or something like that,” said Dr. Padraig Duignan, chief pathologist at the Marine Mammal Center in Sausalito.

The whales were on their yearly migration from the warm birthing waters off the coast of Baja en route to the summer feeding ground in Alaska where they pack on the blubber.

At least one of the animals studied by the Marine Mammal Center, a female, was severely malnourished.

“Right now, they’re heading for Alaska. They’re in the poorest body condition they’re ever going to be in because they’ve gone through the winter with no feeding,” said Dr. Duignan.

The yearling didn’t appear to have enough fuel to make the journey.

“The most significant thing was that she just had no body reserves left. She had some blubber depth but she had subcutaneous fat, she had no internal body fat. These are reserves that any animal — human or animal — needs to maintain body temperature and normal function,” Dr. Duignan explained.

This pair marks the second and third dead gray whales found in the bay in the past two years. There is a growing worry among biologists that this is a marker that the environment in Alaska is changing and endangering the whales.

“It has to be a concern for us. It has to be an area of warning that perhaps something is changing drastically in their habitat in the north in the arctic waters, that they’re not getting enough food,” Dr. Duignan said.