The Tokyo District Court on Wednesday handed down a two-year suspended prison sentence and five years' probation to anti-whaling activist Peter Bethune for his role in boarding a Japanese whaling ship and obstructing their activities.

The damaged powerboat Ady Gil, which belongs to the Sea Shepherd Conservation Society, floats near the Japanese ship Shonan Maru No. 2 after a collision between the two vessels in the Southern Ocean January 6, 2010. Anti-whaling activists accused Japanese whalers of ramming and sinking the high-tech protest boat in the frigid Southern Ocean on Wednesday, but Japan said that its ship could not avoid the collision. Picture taken January 6, 2010. [Xinhua/Reuters Photo]

Bethune, 45, who comes from New Zealand, was found guilty on five charges, spanning from assault to trespassing -- the defendant had previously pleaded guilty to all charges except for assault.

Bethune's defense counsel had sought a suspended prison sentence as he had admitted his culpability in the majority of charges and had expressed deep regret for his actions.

The prosecution team, however, had been pushing for a two-year prison sentence for the activist, highlighting the issue of Bethune throwing bottles of butyric acid at the Shonan Maru No. 2 whaling vessel.

Bethune, a member of the controversial Shepherd Conservation Society, said that he believed the bottles of butyric acid he threw were non-toxic and would not harm anyone, however prosecutors claimed the rancid liquid burned two crew members aboard the Shonan Maru No. 2 -- the final ruling concurred that Bethune obstructed business, and injured a 25-year-old crew member of the Shonan Maru No. 2.

Bethune claimed he boarded the Shonan Maru No. 2 from a jet ski on Feb. 15 to hand the ship's captain a bill and letter of complaint claiming damages concerning the wrecking of the Ady Gil, as well as to make a citizen's arrest on the ship's captain for the attempted murder of one of his crew members.

These actions followed a collision between the Ady Gil vessel, which was subsequently wrecked, and the Shonan Maru No. 2, while the Ady Gil was trying to obstruct the main whaling fleet's activities. The incident took place in early January.

The New Zealander was arrested by the Japan Coast Guard at the Tokyo port on March 12 and was remanded in custody.

This is the first time an anti-whaling protester has been brought to Japan for trial and prosecuted.

Japan stopped whaling for commercial purposes in 1986 in line with international law, but has exercised its right to hunt whales for what it claims to be scientific purposes, although does little to hide the fact that whale still appears on the menu in many Japanese restaurants.