Rob Stewart, the director of Sharkwater, is a photographer and biologist who set out to make a movie that would change public misconceptions about sharks. This turned into a four year long project that saw him team up with activist Paul Watson of the Sea Shepherd Conservation Society to expose a black market trade in shark fins, the  economic grasp of which is second only to that of the drug trade.

What started out as a cool eco-film has become a global campaign to raise awareness about the rapid demise of the ocean's top predator.

I had the opportunity to speak with him about his first film.

First of all, thanks for taking the time to talk to me. You must be getting sick of answering the same questions over and over again.

Oh, no problem. I've been trying to get people to listen to me talking about sharks for years, I love talking about them.

Some of the footage is amazingly beautiful and devastating. Is all of the footage yours?

Uh no, some of the footage came from conservation groups.

You teamed up with Paul Watson of the Sea Shepherd Society and joined a campaign to protect sharks from illegal poaching in Costa Rica and the Galápagos. I'm interested in how you came to meet Paul Watson.

Well, when we first started all this, there were virtually no conservation groups doing anything to protect sharks, so we spent about a year trying to raise funds and after about a year, the Charles Darwin Society told us that Paul Watson and Sea Shepherd had donated a boat to the Galápagos, which is what we were trying to do. So I checked out Sea Shepherd and found out they were about to launch a couple of campaigns in Costa Rica and the Galápagos. So I got in touch with him.

[NOTE: On their way to Costa Rica, they came across a Costa Rican boat illegally fishing and shark finning in Guatemalan waters. Upon instructions from Guatemalan authorities, the Sea Shepherd's ship The Ocean Warrior confronted the illegal fishing vessel and tried to bring them in for arrest. This led to a dangerous confrontation, a ship collision and ultimately, it was Paul Watson, Rob Stewart and the rest of the Ocean Warrior's crew facing arrest in Costa Rica on seven counts of attempted murder.]

When you first got into Costa Rica and were arrested, how did you manage to save all of your footage?