An antiwhaling activist from New Zealand was convicted and given a suspended prison term Wednesday for interfering with a Japanese whaling ship and illegally boarding it in the Antarctic Ocean in February.

The Tokyo District Court gave a two-year prison term, suspended for five years, to former Sea Shepherd member Peter Bethune, 45, for launching a bottle containing butyric acid onto the Shonan Maru No. 2 that injured one of its crew members on Feb. 11, and for illegally boarding the vessel on Feb. 15.

Bethune was not planning to appeal, according to his counsel. After the ruling, the former Sea Shepherd member, who was expelled from the U.S.-based group during his trial in early June, was taken into custody by immigration authorities.