Clashes at sea with two environmental groups will not bring Japan's whaling programme to a halt but could reduce the size of the catch, a senior official at the Fisheries Ministry said on Thursday.
The confrontations with Greenpeace and the more militant group Sea Shepherd, which have led to at least two collisions in remote Antarctic waters in recent weeks, could mean Japan catches fewer whales than it had planned for the season, Hideki Moronuki, head of the whaling section at the ministry, said.
Two Greenpeace ships set off from Cape Town in November to pursue and disrupt the Japanese whalers, sometimes deploying inflatable boats between the whales and harpoon guns.
Sea Shepherd has also been pursuing the whaling fleet.
"If the harassment continues there may be some effect," Moronuki said.
"But I want to make it quite clear that Japan will not cancel its research, whatever dangerous activities or interference may occur," Moronuki added.
Japan, which abandoned commercial whaling in 1986 in line with an international moratorium, says its current whaling programme is for research purposes. Critics dispute this because the meat ends up in Japanese fish markets and on restaurant tables.
"We have experienced disruption in the past, but this time it has been more aggressive than ever," Moronuki said of the environmentalists' tactics.
He said the escalation was likely due to Japan's expansion of its whaling programme this season.
The six-ship Japanese fleet, which set out in November, aims to catch 850 minke whales before returning to port in April, almost double the previous target of 440. It also plans to add 10 fin whales to its haul for the first time.
The ministry on Wednesday released video footage of a Jan. 8 collision between the whaling ship Nisshin Maru and the Greenpeace ship Arctic Sunrise, which it said showed Greenpeace had deliberately rammed the Japanese vessel.
Greenpeace has blamed the whaling vessel for the collision, which caused some damage to both ships but did not injure anyone on board.
Separately, the Sea Shepherd organisation has said its ship the Farley Mowat deliberately sideswiped a Japanese whaling supply ship on Sunday.
Japan's Fisheries Ministry has said it believes the two groups are working together.
Greenpeace has disavowed tactics that might endanger the lives of the Japanese crew but has promised to continue its disruption campaign.