Mystery as harbor porpoises found 60 miles upstream in San Francisco
Two harbor porpoises that entered the San Joaquin River near San Francisco in September have now traveled even further upstream. The mother and calf were spotted near Bethel Island in the San Joaquin River on September 25, 60 miles inland from the ocean. … Bill Keener, a researcher and member of the Cetacean Field Research Team at The Marine Mammal Center, told Newsweek … harbor porpoises will sometimes travel upriver in other parts of the world, such as in 2009, where harbor porpoises in London made it up the Thames as far as Kew Gardens. While the San Joaquin River journey may be extreme for a harbor porpoise, it is not a record for cetaceans: Beluga whales are known to travel far upstream in the Arctic, with belugas going 60 miles upriver to the town of Bethel, Alaska last year.
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