PARIS - Environmental activists opposed to the fishing of the endangered bluefin tuna faced off again on Monday with French commercial tuna fishing vessels in the Mediterranean sea near Malta.

The owner of the two fishing vessels involved, Jean-Marie Avallone, told AFP that one fisherman was injured after the Greenpeace ship Arctic Sunrise rammed one trawler.

But Greenpeace rejected that claim and said its ship had been trying to free tuna caught in cages and that it had turned around and sailed away as soon as it saw the two fishing boats heading towards it.

"There was no contact between our militants and the crews of the fishing boats. And therefore no injured people," said Isabelle Philippe, spokeswoman for the group in France.

Fishermen on Friday hurled a grappling hook at a Greenpeace dinghy trying to free bluefin tuna from their nets off Malta, injuring an activist whose leg was pierced by the hook.

Conservation Society Sea Shepherd has said it would on Monday launch a "Blue Rage" campaign against the poaching of threatened bluefin tuna in the Mediterranean.

The group's boat arrived on Saturday in Malta, according to its director Lamya Essemlali, who said she would join the vessel and its crew of 40 people to launch the campaign which would last until mid-July.

The legal fishing period for the fish is May 15 to June 15, but even during that period the catch is capped by strict international quotas.

Since the industrial fishing era began, stocks of bluefin tuna have fallen by at least 85 percent in the Mediterranean and eastern Atlantic, where they come to spawn in the warmer waters.