EXCLUSIVE: The near-mythical pink river dolphins of the Amazon, the largest river dolphin species in the world, are on the verge of extinction thanks to fishermen who continue to hunt the docile animals and use them as bait. But two activists – Dr. Fernando Trujillo, a renowned marine biologist, and Richard Rasmussen, a biologist and reality TV star – are determined to raise awareness of the dolphin’s situation and protect this endangered species.

Directed by Mark Grieco (Marmato), an indie filmmaker and photographer who focuses on human rights and the global economy, A River Below examines the massacre of this incredible dolphin as well as dealing with ethics in activism and how the media is being manipulated to achieve certain goals. It also explores the ethical dilemmas we face and what must be done to achieve change.

Here’s an exclusive clip from the powerful doc, which sees the former director of the World Animal Protection group in Brazil explain just how vast the problem of killing pink river dolphins is and how difficult it is to find the culprits.

A River Below also delves into the bigger picture of the various sides, and generates a conversation about the ethics in activism, and who is right or wrong in a situation where there is no easy divide.

The film is playing in the Documentary Competition section at Tribeca this year, where it will have its world premiere April 22.