Underwater: northern sea lions flock to a tiny island

Nearly one thousand sea lions gathered in northern Japan in March 2017. This rare footage was filmed close to Bentenjima Island, an inhabited island located near Cape Soya, in northern most Hokkaido.
Every winter, about one hundred northern sea lions come to this tiny island, but curiously, this winter, almost one thousand flocked to the island. A scientist says this phenomenon has never happened before. Recently, the areas of drift ice in the Sea of Okhotsk facing northern Hokkaido have shrunken due to global warming. As a result, the territories of northern sea lions has expanded and many of them have come near Bentenjima Island. Sea lions are known to people as animals having high learning capability. They are friendly and curious to people. However, these sea lions are not always welcome to local fishermen. They eat seafood for human consumption. The damage cost is reportedly over 16 million US dollars. Japanese Fisheries Agency are strengthening efforts to control their numbers.