Another member of the West Coast's endangered southern resident killer whale population is missing and feared dead, according to experts.

On its website, the U.S.-based Centre for Whale Research wrote that L41, an adult male, was not present during a recent encounter with his pod.

"Given his age and that he looked a little thin in our January 2019 encounter, we fear he may be gone and will consider him missing unless he shows up unexpectedly in an upcoming encounter," the group wrote.

The group's last record of L41 was from last summer, when Victoria photographer Mark Malleson captured the whale with his pod in August 2019.

The whale, nicknamed Mega, is around 43 years old. He was born a year after the centre's study on the southern resident population began researchers there have been able to see him grow from calf to adult.

In 2019, the southern resident killer whale population dropped to 73 members — a number that included L41. The whales have struggled in recent years; three whales from the group died last summer.

These whales, which are listed as endangered under the Canadian Species at Risk Act, frequent the area of the Salish Sea and feed primarily on chinook salmon.