(Cannon Beach, OR) -- A fourth whale has been found dead on an Oregon beach. The body of a gray whale was found Saturday near Cannon Beach. Officials with the Seaside Aquarium say it appears to have been dead about a month. That may make it difficult to determine the cause of death. A shark bit the whale, but that happened after it was dead. It doesn't appear any of the whale deaths are connected. This is the time of year when whales are swimming south to Baja California and there are thousands of gray whales taking part in the migration.