Environmentalist Paul Watson has been detained until August 15, authorities and his foundation said.

Veteran environmental activist and anti-whaling campaigner Paul Watson has been apprehended by Greenland police following an international arrest warrant issued by Japan.

Watson, a 73-year-old Canadian-American citizen, is the former head of the Sea Shepherd Conservation Society whose direct-action tactics, including high-seas confrontations with whaling vessels, have drawn support from A-list celebrities and been featured in the reality television series called Whale Wars.

Japan, which says eating whale meat is part of its culture, resumed commercial whaling in 2019 and has since modernised its fleet and expanded its catch list, drawing condemnation from conservationists who fear for the fate of the large ocean mammals.

“The Japanese authorities have issued an international arrest warrant for Paul Watson, which is the reason why the Greenland Police were ready to arrest him on arrival in Nuuk,” Greenland’s law enforcement agency said in a statement on Monday.

After his arrest, Watson appeared before a district court to look into a request to detain him pending a decision on his possible extradition to Japan, the statement added.

On Monday, the Captain Paul Watson Foundation told the Associated Press that the veteran environmentalist would be detained in Nuuk at least until August 15, following the court’s decision, to give the Danish Ministry of Justice time to investigate the case and possible extradition.

He faces a maximum sentence of 15 years in prison in Japan, according to the foundation, which also said the Greenland court wouldn’t allow Watson’s release on bail as he was considered a flight risk.

“We implore the Danish government to release Captain Watson and not entertain this politically-motivated request,” Locky MacLean, the foundation director, said in the statement.

Greenland is an autonomous territory of Denmark. Japan does not have an extradition treaty with the European country and it is unknown if or when Watson would be handed over.

Neither the Japan Coast Guard nor Japan’s Foreign Ministry, which had issued the international warrant for Watson, confirmed they were negotiating Watson’s handover.

However, the coast guard, the primary investigative authority in Watson’s case in Japan, said on Monday that officials were on standby if a handover is ordered.

It’s not the first time Watson’s tactics have brought him head-to-head with authorities.

He was detained in Germany in 2012 on a Costa Rican extradition warrant, but skipped bail after learning that he was also sought for extradition by Japan, which has accused him of endangering whalers’ lives during operations in the Antarctic Ocean.

Watson has since lived in countries, including France and the United States.