The Cascadia Research Collective said the whale was dead. They posted this news on Facebook.

The group is checking if it is safe to examine the whale.

The whale was first seen in the river last Wednesday. It was 145 miles from Seattle.

The whale looked thin but was acting normally. It had no visible injuries.

The researchers hoped the whale would leave the river on its own, but it did not.

Gray whales migrate to the Arctic to eat. They use up their food stores during this trip. When they do not find enough food, they look for new places to eat. This is what probably happened to this whale.

Gray whales in the Pacific Ocean have not had enough food in recent years.

Gray whales are in a crisis because they are not finding enough food in the Arctic.

Gray whales can grow up to 49 feet long and weigh 90,000 pounds. They are important for whale watching and tourism.

Gray whales face many dangers, including being hit by ships and getting caught in fishing nets. They usually travel alone.

Two adult gray whales were found dead in the area earlier in April. They were malnourished and one had a head injury from a ship.

The number of gray whales is declining. There are only about 13,000 left, which is the lowest number since the 1970s.