Japan's hot-button dolphin hunt is just one of nine charged environmental issues that are explored at the 2009 Hot Docs Film Festival in Toronto (April 30 to May 10).

Billed as North America's largest documentary festival, 171 films from 39 countries will be screened at the 16th annual festival.

The mix is an eclectic one, spanning the gamut from America's secretly gay politicians to the aftermath of "Borat" in Kazakhstan.

Yet major environmental concerns cannot be missed in illuminating films included in Hot Docs' World Showcase, Canadian Spectrum and Special Presentation series.

"We're seeing a huge eco theme emerge this year," says Sean Farnel, Hot Docs' director of programming.

"The Cove," one of Farnel's favourite entries, spotlights the annual slaughter of more than 2,500 dolphins in a cove at Taiji, Wakayama in Japan.

The film won the U.S. Audience Award at the 2009 Sundance Film Festival.

Produced by actor Fisher Stevens and directed by National Geographic photographer Louie Psihoyos, "The Cove" was filmed secretly using underwater microphones and high-definition cameras disguised as rocks.

"It's an activist thriller," says Farnel. "It's entertaining. It's powerful. It's a strong story. It's got all those things that great movies are supposed to give us."

Other eco-themed gems including Kevin McMahon's "Waterlife," a profile of the beauty and toxicity of the Great Lakes, should impress the 100,000 spectators and 2,000 industry delegates expected this year.

Rupert Murray's "End of The Line" delivers a disturbing wakeup call about humanity's overconsumption of fish and how, if it continues at this level, will deplete world stocks by 2048.

Alberta's Athabasca oil sands drive "H2Oil," Shannon Walsh's eye-popping exploration into their impact on local water ecology and peoples' health.

"Anyone who starts to pull back the curtain, not just on the tar sands but on any environmental issue today, will find lots to be disturbed about," Walsh told CTV.ca during a phone call from Montreal.

Before Greenpeace came to the tar sands Walsh was diving into the great divide between environmentalists, oil corporations and government. Their beef? How do you serve the economy and save the planet at the same time?

"You can ask what's more important: Oil or water? But there's a bigger question here and it concerns our ability to live on the planet," says Walsh. "These are life and death questions for all of us."

Star-powered projects

The endless anxieties of our times are also reflected in other Hot Doc entries.

"Reporter," which features Ben Affleck as its executive producer, follows Pulitzer Prize-winning New York Times columnist Nicholas Kristof through the ravaged villages of the Democratic Republic of Congo. It's a gripping trek through an unsalvageable disaster zone where 5.4 million people have died.

"Celebrities who are politically or socially engaged are finding documentaries a very attractive art form to fund and lend their support to," says Farnel.

In "Prom Night in Mississippi," actor Morgan Freeman funded a non-segregated prom in his home town - a place that traditionally held white and black dances.

The Oscar winner put forward his offer to the town in 1997. They finally accepted in 2008.

"Morgan couldn't believe in this day and age that this kind of segregation still was going on. He wanted to give the town a less prejudiced alternative," says Farnel.

Gay secrecy, the power of spirituality

Surprising films like "Outrage," by Oscar-nominated American director Kirby Dick, puts a glaring spotlight on secretly gay politicians who campaign against same-sex rights in the U.S.

In "Act of God," the first Canadian doc to open Hot Docs, director Jennifer Baichwal offers an absorbing meditation on the spiritual and metaphysical changes people undergo after being struck by lightening.

The impact of spirituality also drives "Fierce Light: When Spirit Meets Action."

Directed and written by Velcrow Ripper, the NFB co-production takes a hard look at how spirituality and activism co-exist. It also features interviews with such spiritual luminaries as Archbishop Desmond Tutu and Thich Nhat Hanh.

Finally, after being vilified as Kazakhstani whores, thieves and abortionists in Sacha Baron Cohen's "Borat," the affronted villagers look for payback in "Carmen Meets Borat." Pride. Betrayal. A US$30 million lawsuit waged by villagers. Director Mercedes Stalenhoef goes for the jugular in this darkly comic film.

"All these films have work to do in today's world," says Farnel. "Hopefully they'll reach the audiences they need to reach and enlighten people along the way."