Ocean scientists fear the number of dead gray whales washing up on the US West Coast this year is at its highest in nearly two decades.

As of Thursday night, 58 gray whales had washed ashore from California to Alaska, compared with 45 all of last year, the National Oceanic and Atmospheric Administration said. Some were underweight, leading scientists to believe they didn’t have enough food.

“Why these whales are malnourished is a mystery that we are trying to unravel,” said NOAA spokesman Michael Milstein. “Something is going on.”

The last time researchers saw numbers this high was in 2000, when 131 deaths were recorded.

Milstein said climate change may contribute. “That’s an angle they’re investigating,” he said. “We don’t know anything for sure at this time.”

Gray whales spend half the year in Mexico and the summer in the Arctic, where they feed for most of the year.

“The water there has been unusually warm for several years,” which affects the sea ice and could be a food source for the whales, he said.

Milstein said something unusual may have happened last year that prevented them from eating enough to sustain themselves.

“The die was cast last summer,” he said.

NOAA estimates the total population of gray whales on the West Coast at 27,000, the highest recently recorded. Indeed, researchers wonder if they are in trouble because there is more competition for food.

The whales can weigh up to 90,000 pounds. They were removed from the Endangered Species List in 1994.

In Washington, 18 giants have died this year, said researcher John Calambokidis of Cascadia Research. He only remembered two years like this. In 1999, there were 27 deaths in the state; in 2000, it had 23.

He said he was also concerned about so many deaths being detected so early. “Most of the dead animals we saw were malnourished and emaciated. We don’t have direct evidence but it is particularly relevant to changes in Arctic ecosystems.”

But he said it was still too early for researchers to determine the cause.

Ten people are stranded in the San Francisco Bay Area. Dr Padraig Duignan of the Marine Mammal Center said the rate was “causing serious concern”. At least four of them died of malnutrition.

Officials at the center said biologists observed gray whales “in poor body condition” this year, possibly “due to unusual ocean conditions” that contributed “to changes resources”. food”.