Anti-whaling activists accuse Japan fleet of attackSea Shepherd Conservation Society anti-whaling vessel Ady Gil on 6 January 2010 - photo from Institute of Cetacean Research of JapanThe Sea Shepherd said the bow was sheared off the Ady GilAnti-whaling activists have accused a Japanese vessel of ramming their high-tech speed boat during a confrontation in the Southern Ocean.The Sea Shepherd Conservation Society says its vessel was sliced in half, but all six crew were rescued.Earlier the campaigners - who are trying to stop Japan's whaling fleet - said they threw chemicals onto the whaling boat to prevent it being used.Japan's fisheries agency said the group had obstructed the whalers' operations.The agency said it was the fourth time this season that the anti-whaling activists had interfered with the whaling fleet's operations, Kyodo news agency reported.In recent years the two sides have confronted each other regularly in waters around the Antarctic."This seriously escalates the whole situation," Sea Shepherd spokesman Paul Watson said, according to The Age newspaper in Australia.The activists said their boat, the Ady Gil - a high-tech speed boat that resembles a stealth bomber - had its bow sheared off in the clash near Commonwealth Bay.The Sea Shepherd group sends boats to Antarctic waters each year to try to stop the Japanese whaling fleet hunting whales under the auspices of a scientific research programme.Japan abandoned commercial whaling in 1986 after agreeing to a global moratorium but international rules allow it to carry out a limited whaling programme.