Coast guardsmen will join the crew of Japanese "research" whaling vessels in the Antarctic Ocean this winter to respond to increasingly violent obstructionist tactics being used by environmental groups, the Japan Coast Guard said Monday.

"We have decided to beef up security as never before," a coast guard official said, refraining to give specifics, including how many guardsmen will be aboard the vessels and what kind of equipment they might carry.

Coast guardsmen were aboard Japanese whaling vessels in fiscal 2007 and 2010. Japan has been hunting whales since 1987 for what it calls scientific research purposes. Environmentalists condemn the activity as a cover for commercial whaling, because most of the meat from the harpooned whales ends up being sold for consumption.