Gray whales that have starved to death are washing ashore along the US Pacific coast at an unusually high rate this year, according to marine scientists.
A total of 31 gray whale carcasses, many of them emaciated, have been spotted on beaches in Washington, Oregon and California.
That's the most dead gray whales since 2000, when 86 carcasses were found.
Dozens more of the aquatic mammals have shown visible signs of malnutrition. Scientists say the gray whales are leaner than usual. Some they've seen were so skinny their bones were visible.
'Their skeleton seems to stick out more and more,' Dr. Padraig Duignan, chief pathologist at the Marine Mammal Center in Sausalito, California, told the LA Times on Friday.
Frances Gulland, a research associate at the University of California, Davis School of Veterinary Medicine, said the number of gray-whale deaths could reach 60 or 70 by the end of the animals' migratory season from the warm breeding waters near Mexico to the frigid feeding grounds in the Arctic.
'If this continues at this pace through May, we would be alarmed,' Gulland told the LA Times.
Sightings of gray whale mother and calf pairs also have been down this year. Scientists aren't yet sure what's causing the gray whales to starve, as other whale species in the region haven't shown the same distressing signs.
Researchers suspect the whales didn't consume enough in the North Pacific and Arctic during their feeding season last summer, but it's too early to say definitively or to pinpoint why that would be.
The animals usually pack on as many pounds as possible during that time before migrating south to breed.
There's also the issue of gray whale food supply versus gray whale food demand. The whaling industry decimated the animals' population for more than three centuries, but their numbers have since rebounded.
The eastern North Pacific gray whale was removed from the US endangered species list in 1994, according to the World Wildlife Foundation.
The global gray whale population has swelled to an estimated 27,000 whales, according to the LA Times.
'It looks like we have a gray whale population that has recovered from whaling, but is potentially hitting a limit in terms of food supply,' Cascadia Research biologist John Calambokidis told Kiro 7 in western Washington on Tuesday.
Calambokidis was one of the marine scientists examining the body of a dead gray whale that washed up on a local beach in Ocean Shores, Washington last week.
Researches said they found very little food in the dead whale's stomach.
Calambokidis said the number of dead whales that wash ashore are likely a small number of the whales that are dying in the ocean.
'The dead animals we see only represent a fraction of the true animals dying. Emaciated animals will sink when they die and they'll never be discovered,' he said.