International participants at a high-level conference on the world's oceans pledged more than $5.3 billion for conservation and designated vast areas as protected waters, U.S. Secretary of State John Kerry said on Friday. More than 90 countries took part in the two-day conference, the third of its kind, in an effort to galvanize attention to the dangers that pollution, climate change and over-fishing may pose to the world's oceans. More than 1.3 million square miles (3.4 million square km) gained protected designation. The United States and more than 20 countries joined on Thursday at the conference to create 40 marine sanctuaries around the world to protect the oceans. They limit commercial fishing, oil exploration and other activities that affect ocean ecosystems. President Barack Obama also designated the first U.S. marine reserve in the Atlantic Ocean: 4,913 square miles (12,724 square km) known for underwater mountains and canyons off the coast of New England. The announcement was part of more than 136 new initiatives unveiled during the event. Kerry, speaking to a Georgetown University audience on Friday as part of the conference, stressed the health of the world's oceans for national security and global stability. This is life and death. This is national security. It is international security," he said, saying nearly 50 percent of the world depends on food from the ocean and 12 percent of the world's work force relies on the ocean for their livelihood.