It was the latest clash between conservationists trying to end a hunt that they view as cruel and Canadian authorities who defend it as well-managed and as an important source of income for coastal communities.
Paul Watson, the head of the U.S.-based Sea Shepherd Conservation Society, said coast guard members boarded his group's vessel, the Farley Mowat, in the waters of the Cabot Strait.
They "took command of the vessel," Watson said. "They were screaming at people to lie down on the deck."
Canada's federal Fisheries Minister Loyola Hearn said the captain and chief officer were arrested for allegedly interfering in the hunt.
"We will continue to protect sealers while ensuring the sustainable and humane management of the hunt, so it continues to provide economic opportunities for Canada's coastal communities," Hearn told reporters in Ottawa.
The minister said the boarding was necessary because the crew of the Mowat had refused numerous requests to "cease and desist" their activities and to head for port.
He said the Royal Canadian Mounted Police asked permission to board the vessel, but were refused.
Hearn said the crew of the Mowat was "safe and unharmed" following the boarding, and the ship would be taken to Sydney, Nova Scotia, by early Sunday.
Watson said the conservation group had been filming seals being slaughtered and he believes the footage will be damaging to Canada, particularly as the European Union considers whether to ban the import of seal products.
The conservation group's captain and first officer were charged last week with obstructing the hunt soon after the March 28 opening of the annual hunt, the largest marine mammal hunt in the world.
The Fisheries Department charged the captain, Alexander Cornelissen, and First Officer Peter Hammarstedt with breaking a law that prohibits those without an observation license from coming within 985 yards of the hunt.
Cornelissen is also charged with obstruction or hindrance of a Fishery Officer or inspector.
If convicted, the men face fines of up to $99,400 and one year in prison.
Fishermen sell seal pelts mostly to the fashion industry in Norway, Russia and China, as well as blubber for oil. The United States has banned Canadian seal products since 1972.
On the Net:
Fisheries and Oceans Canada: http://www.dfo-mpo.gc.ca
Sea Shepherd Conservation Society: http://www.seashepherd.org
© 2008 Associated Press