An investigation laid blame on both anti-whaling vessel Ady Gil and Japanese whaling ship Shonan Maru No. 2 for their Southern Ocean collision. The Ady Gil was on a Sea Shepherd Conservation Society mission aimed at stopping Japanese whaling when it crashed into the Shonan Maru on 20 January 2010. The impact tore off 3.5m of the Ady Gil’s bow. The boat’s skipper, conservationist Peter Bethune, was later put on trial in Japan after trying to make a citizen’s arrest of the Shonan Maru No. 2 captain. A Maritime New Zealand investigation found both vessels disobeyed international anti-collision rules for ‘close quarters’ encounters. Neither the Shonan Maru No 2 captain or Mr Bethune were charged with deliberately causing the impact.