On Sunday 7 February, rain fell without let-up over Venice, the sky and the lagoon merging into a single milky colour, while the Jolly Roger flag of Sea Shepherd — depicting a skull adorned with a dolphin and a sperm whale, and a trident crossed with a shepherd's crook — snapped in the wind.

The adverse weather did not, however, deter the hundreds of people who flocked to the Marina Vento di Venezia dock on the island of Certosa to admire the Bob Barker, meet the crew and show their support for Sea Shepherd — an organisation that for nearly forty years has been fighting to counter the massacre of wild species that inhabit the oceans and their ecosystems.

On the small Venetian island, enthusiasm and an incredibly positive energy filled the air, because, at the end of the day, "Sea Shepherd is more than a simple organisation — it's a movement," Alex Cornelissen, CEO of Sea Shepherd Global and long-standing captain of the Bob Barker, reminded those gathered at the press conference. Sea Shepherd had not been stopped even by Saturday's mishap, when the Bob Barker ran aground on a shoal in the Venice lagoon and subsequently had to be towed free by two tugboats. "In the past we have faced many very dangerous situations, but it seems the mudflats of the Venice lagoon are no less formidable," Cornelissen joked. "Fortunately there was no damage."

It is precisely this extreme determination, hands-on activism and genuine popular participation that sets the organisation founded by Captain Paul Watson in 1977 apart from other environmental groups. We asked Alex Cornelissen what he thinks of other associations and how we might contribute to protecting life in the oceans.

The Sea Shepherd vessel Bob Barker moored at the Marina Vento di Venezia dock, on the Isola della Certosa © Lorenzo Brenna

The jetties of the Isola della Certosa where the Sea Shepherd vessel was moored © Lorenzo Brenna

The press conference organised by Sea Shepherd on the Isola della Certosa © Lorenzo Brenna

Enrico Salierno, vice president of Sea Shepherd Italia, Giorgio Conti, lecturer at the Ca' Foscari University of Venice, and Alex Cornelissen, CEO of Sea Shepherd Global © Lorenzo Brenna

Alex Cornelissen, CEO of Sea Shepherd Global and long-standing captain of the MV Bob Barker © Lorenzo Brenna

A photograph showing the sinking of an illegal fishing vessel during the Ice Fish campaign © Lorenzo Brenna

The Sea Shepherd Jolly Roger flag © Lorenzo Brenna

The vessel Bob Barker was purchased thanks to a $5 million contribution from American television icon Bob Barker © Lorenzo Brenna

The Bob Barker was originally a whaling vessel; it now serves to protect cetaceans © Lorenzo Brenna

The deck of the Bob Barker, the nightmare ship of the Japanese whalers, which last year helped save over 900 whales in the Arctic © Lorenzo Brenna

The Bob Barker, captained by Antonio Sueiras Zaurin, has been active since 5 December 2009 © Lorenzo Brenna

Aboard Sea Shepherd vessels, the captain is the only person to receive a salary © Lorenzo Brenna

The crew equipment of the Bob Barker © Lorenzo Brenna

The crew list of those on board the Bob Barker. Among those on board is an Italian volunteer, Melissa Bortolin © Lorenzo Brenna

The command room of the vessel Bob Barker: technology reigns supreme, but knowing how to read a nautical chart is still very useful © Lorenzo Brenna

Andrea Ferrari, a Sea Shepherd land volunteer, during the tour on board the Bob Barker © Lorenzo Brenna

The photograph hanging on the wall bears witness to one of the organisation's most memorable and potentially dramatic moments: the ramming of the Bob Barker by the whaling vessel Nisshin Maru © Lorenzo Brenna

The vessel, functional and spartan, nonetheless has a lounge where crew members can, among other things, play guitar and swap stories © Lorenzo Brenna

Freezer containing fruit. Only vegan meals are served aboard Sea Shepherd vessels © Lorenzo Brenna

Omar Francoletti, a Sea Shepherd land volunteer, Linda Possanzini, Sea Shepherd Italia coordinator for Marche and Umbria, and Frederic Bessone, a volunteer who joined the ship for a year © Lorenzo Brenna

Do you think other environmental organisations could be more actively engaged in protecting the environment?
Absolutely yes! I don't want to point the finger at anyone, but WWF and Greenpeace have major contradictions. I find it absurd, for example, that Greenpeace, whose mission is to protect the environment, has freezers full of meat and fish. How can you claim to defend nature if you eat it?

Can a vegan diet have a positive impact on the environment, and on the marine environment in particular?
Certainly — in fact, on board our ships we serve exclusively vegan meals. There are various reasons for this: first of all, eating meat and fish has a huge impact on the entire planet, and besides, it would make no sense to cross the oceans to save marine wildlife while at the same time eating cows and chickens. It is now clear that the only sustainable diet is a vegan one. We decided to adopt this policy also to set an example to the people who follow us. I became vegan in 2004 — back then it was difficult to find vegan food outside the United States, whereas today you can find a vegan restaurant in almost every part of the world. It's only a matter of time before a veg restaurant receives a Michelin star.

Pollution in the seas is even worse than fishing in terms of environmental impact. What do you do to combat it?
It's an enormous problem. Here in Venice I brought a special piece of equipment that we use to collect plastic from the oceans; we then report the data gathered to an organisation that measures the percentage of plastic present per square kilometre of water. In this way we hope to contribute to scientific research and to provide detailed information on marine pollution. Furthermore, in the course of our missions we sail in remote waters that are seldom visited by other ships, so it is a good opportunity to share these experiences and the data collected with the scientific community. Sailing across the Antarctic Ocean you can admire extraordinary landscapes and habitats, but even there plastic is everywhere. It is necessary to act on multiple levels: clean up coastlines, stop dumping waste at sea, and curb the production and consumption of plastic.

What has been the most intense experience you have had since joining Sea Shepherd?
A whole day wouldn't be enough to recount them all; I do remember in particular the first time I went on board. We were sailing near the Galapagos when we first encountered an enormous pod of dolphins, then came across some gillnets in which a sea turtle was trapped. That day I marvelled at the beauty of marine life and truly understood the importance of what we do.