The anti-whaling organisation Sea Shepherd will not contest the Southern Ocean against Japanese whalers this season, Captain Paul Watson has announced, accusing “hostile governments” in the US, Australia and New Zealand of acting “in league with Japan” against the protest vessel.

Sea Shepherd has been obstructing Japanese whaling vessels in the Southern Ocean each year since 2005, but Watson said the cost of sending vessels south, Japan’s increased use of military technology to track them, and new anti-terrorism laws passed specifically to thwart Sea Shepherd’s activities made physically tracking the ships impossible.

Australia took Japan to the international court of justice over its Southern Ocean whaling program in 2014, winning a judgment that condemned Japan’s whaling programs as being in breach of the International Whaling Commission’s ban on commercial whaling. The court rejected Japan’s argument that its whaling was for “scientific” purposes.

Watson said his volunteer organisation could not compete with Japanese military satellite technology, which tracked Sea Shepherd in the ocean. Japan has also passed anti-terrorism laws that make protest ships’ presence near whalers a terrorist offence.