Southern resident killer whales made their first appearance in the Salish Sea on Canada Day after more than two months with only a brief sighting off the west coast of Vancouver Island.

Southern resident killer whales which are often spotted in the Salish Sea near Vancouver throughout June haven't been seen this season, and scientists believe that could be because of the lack of chinook salmon.

The most common pod of southern resident killer whales who migrate to the Salish Sea during the summer have not been seen for than 100 days, marking a highly unusual absence from their historic summer hunting ground, according to researchers.