British entrepreneur Richard Branson handed over a petition with more than a million signatures to the UN, urging governments to protect at least 30 percent of the world's oceans by 2030.
Speaking to reporters after the first Ocean Conference convened by the United Nations, Branson reiterated his criticism of US President Donald Trump's withdrawal from the Paris climate accord, saying it didn't make sense.
"I think this is where the American President Donald Trump was so naive. Clean energy can be massively cheaper than dirty energy and everybody can benefit from it," he said.
"If we can manage our oceans properly and create marine reserves... within these reserves, fish can replenish."
The petition contained 1,021,874 names. Noting a goal to make the world carbon neutral "for our grandchildren" by 2050, Branson also drew attention to the erosion of Australia's Great Barrier Reef.
"The Great Barrier Reef is disappearing," he said. "It is related to the sea heating up and to lose one of the biggest wonders of the world is to cry for."