Seven gray whales were found dead on Alaska’s shores over the holiday weekend, sending this year’s toll in the state to 22.

According to the National Oceanic and Atmospheric Administration, a necropsy to help determine the cause of death was performed on one of the four animals that turned up around Kodiak Island. Two others were discovered in Egegik and another at Takli Island. The whales were all found between July 5 and 7.

NOAA Fisheries Alaska region spokesperson Julie Speegle told HuffPost on Friday that while the investigation of the deaths remains in its early stages, starvation triggered by melting sea ice may be a cause.

“As many of these whales have been skinny, scientists theorize there may have been a disruption in the gray whale food source due to a lack of sea ice in the Arctic last summer,” Speegle said. “Gray whales fatten up during the summer by feeding on marine life in the Arctic, mostly amphipods off the ocean floor. But when sea ice melts and retreats (as it did last summer), there is a disruption in the food web that results in fewer amphipods for gray whales to eat.”

Though Speegle did not say whether climate change could be to blame for the deaths, she noted that Arctic sea ice dropped to its sixth lowest extent on record last summer, “which may have caused a disruption in the food supply for gray whales.”