Three endangered whales that haven't been seen in months are missing and presumed dead, the U.S.-based Center for Whale Research announced Tuesday.

The three missing whales are called J17, K25 and L84, one member of each of the three pods of southern resident killer whales that historically frequent the Salish Sea during the summer.

J17 is 42 years old, a matriarch of J pod and the mother of J35, who carried her dead calf for 17 days last year.

K25 is 28, an adult male in the prime of his life, according to the center.

L84, a 29-year-old male, has been missing from all encounters between the Department of Fisheries and Oceans and L pod on the west coast of Vancouver Island this summer. L pod has not entered the Salish Sea at all this year.

In a release, the center said the three pods now rarely visit their core waters of their habitat -- which include Puget Sound, Georgia Strait, and the inland reach of the Strait of Juan de Fuca -- because of the scarcity of Chinook salmon the whales prey upon.