Japan minister: "great anger" at whale activists

Clashes between Japanese whalers and the Sea Shepherd Conservation Society have become an annual feature of the hunt for whales in Antarctic waters. Australia last month pressed Japan to ensure its ships operate more safely after the activists accused whalers of sinking a powerboat.

The Japanese fisheries agency said activists on Thursday obstructed Japanese whaling in the Antarctic by throwing bottles of what it described as butyric acid onto whaling ships, as well as flashing laser lights and using water cannon.

"I am glad that the crews were not seriously hurt, but I am filled with great anger that they took things to that level," Fisheries Minister Hirotaka Akamatsu was quoted as telling reporters by a ministry official.

Three crew members complained of pain on their skin after the substance, found in rancid butter, cheese and body excretions, splashed onto their faces. But their vision was fine and there was no damage to the ships, the agency said in statements.

International Labor Organization documents say butyric acid can corrode skin, eyes and airways.

Sea Shepherd said activists aboard its vessel, the Steve Irwin, threw bottles of rotten butter onto the Japanese boat after the whalers fired a water cannon to try to destroy a helicopter on the Sea Shepherd vessel.

"The crew of the Steve Irwin retaliated by firing warning flares and using a Delta inflatable to toss bottles of rotten butter onto the decks of the whalers," Paul Watson, head of Sea Shepherd, said on the organization's website.

"It was a very tense five-hour confrontation, but there were no collisions and no injuries...Butyric acid is a foul smelling substance, but does not cause harm upon skin contact. It is less acidic than beer."

Sea Shepherd said Japanese crews had killed no whales since last week and vowed the group would continue to "prevent their whaling operations for as long as possible."

Commercial whaling was banned under a 1986 international treaty, but Japan, which considers whaling a cultural tradition, deflects criticism by saying it culls whales for research.

Sea Shepherd earlier this week said a Japanese whaling vessel had "intentionally rammed" one of its boats, the Bob Barker, in Antarctic waters. Another protest boat, the Ady Gil, sank last month after a collision with Japanese whalers.

(Reporting by Yoko Kubota; Editing by Ron Popeski)