Captain Paul Watson, founder of the nonprofit Sea Shepherd Conservation Society and subject of the Animal Planet reality show Whale Wars, was arrested by German officials in Frankfurt this weekend.

The German police have said that the warrant for Captain Watson's arrest is in response to an alleged violation of ships traffic in Costa Rica, which occurred during the filming of [the documentary film] Sharkwater in 2002, says a statement on the Sea Shepherd website. Watson is at risk of being extradited to Costa Rica.

This violation occurred in Guatemalan waters when Sea Shepherd members  came across the Varadero, a Costa Rican ship. Watson and his crew accused the Costa Ricans of illegally killing sharks for their edible fins.

On order of the Guatemalan authorities, Sea Shepherd instructed the crew of the Varadero to cease their shark finning activities and head back to port to be prosecuted, says the Sea Shepherd statement. While escorting the Varadero back to port, the tables were turned and a Guatemalan gunboat was dispatched to intercept the Sea Shepherd crew.  The crew of the Varadero accused the Sea Shepherds of trying to kill them, while the video evidence proves this to be a fallacy.

Sea Shepherd than fled the scene, but the Costa Rica still maintained its warrant against Watson and his crew.  It is unclear whether the charges against Sea Shepherd still stand today, according to the statement.

This isn't the first time Watson has come under fire for his environmental crusading.

Watson became involved with environmental issues as a young boy, and was one of the initial members of Greenpeace in 1971. But his aggressive style of activism was at odds with the group's non-violent policies, and he eventually left to set up his own Earthforce Environmental Society in 1977. The Sea Shepherd Conservation Society sprang from that group in 1981.  

Sea Shepherd uses innovative direct-action tactics to investigate, document, and take action when necessary to expose and confront illegal activities on the high seas, says the group's mission statement. By safeguarding the biodiversity of our delicately-balanced ocean ecosystems, Sea Shepherd works to ensure their survival for future generations.

Sea Shepherd is best-known for its efforts to stop illegal whale hunting. Watson and his crew are the subject of Animal Planet's Emmy-nominated series Whale Wars, the fourth season of which will premiere on June 3. Cameras follow Watson and crew members as they patrol the frigid waters around Antarctica in attempts to stop Japanese crews from illegally hunting whales there.

The group's practice of purposely ramming into illegal whaling ships has caused some controversy; critics perceive Watson as a reckless vigilante, while fans applaud his stalwart dedication to environmental causes.

Twitter posts from Watson indicate that he is currently being held in Frankfurt and is scheduled for a court appearance on Monday morning.