The Japanese government filed a protest with the Netherlands after an anti-whaling group crashed into a Japanese whaling ship on Friday morning in the Antarctic, media reports said.Japan summoned Dutch Ambassador Philip de Heer to the Foreign Ministry to demand the Netherlands take appropriate measures against a Dutch-flagged vessel for violently harassing and obstructing Japan's research whaling, Kyodo News Agency quoted Japanese officials as saying.The Steve Irwin, the flagship vessel of anti-whaling group Sea Shepherd Conservation crashed into the stern of the Japanese whaler Yushin Maru No 2 early Friday as the group tried to interrupt the transfer of a dead whale up the slipway of the Japanese ship.Reports said that the US-based Sea Shepherd tried to entangle Japanese propellers and activists threw rancid butter at the whaling fleet.Sea Shepherd founder Paul Watson was quoted as saying that the emergence of a second Japanese ship made the collision inevitable, and said the Japanese whalers were acting "increasingly aggressive", threatening the lives of his crew.Minoro Morimoto, the head of Japan's whale research institute ICR said the repeated obstruction by the activists was "criminal" and urged the International Whaling Commission to deplore their actions.Japanese Vice Foreign Minister Nobuhide Minorikawa called the group's action "extremely regrettable".Minorikawa and de Heer agreed that Japan and the Netherlands would continue cooperating to prevent a recurrence of dangerous behaviour at sea.Shigeki Takaya, a Fisheries Agency spokesman for whaling in Japan, called the incident "appalling and unforgivable"."We will ask concerning countries, including Australia, to immediately stop them from carrying out such horrendous acts," Takaya said.One crew member on the Steve Irwin required five stitches after being hurt while disorientated by Japanese long-range acoustic devices, according to the Sea Shepherd. The activists accused the whalers of using high-pressure water cannons and acoustic weapons against them.The Japanese whaling fleet, undaunted by international protests, plans this year to catch about 1,000 whales for "scientific purposes" in the Antarctic ocean.Critics regard Japan's scientific whaling a cover for commercial whaling, while Japan argues that it was necessary catch a number of whales to gain information on whale population figures and data on their migration routes.