Ocean-planning policies are urgently needed to prevent public waters from being damaged by overcrowding, U.S. activists said.

"The oceans are kind of the last frontier for use and development," said Amanda Leland, ocean policy director at the Environmental Defense Fund, an advocacy group. "Even in the 1970s we thought that the oceans were limitless resources of fish. We know today now that fisheries are collapsing all around the world."

The United States is joining Denmark, Belgium, Britain and France in developing plans for their waters to protect ocean ecology, address climate change and promote sustainable ocean economics, CNN reported Friday.

The Obama administration's ocean planning task force is to recommend a national policy in September.

Issues to be considered include wind turbines, pollution runoff, dwindling fish stocks, crowded shipping lanes and industrial cables competing for space on the sea floor, said Charles Wahle, a marine ecologist at the National Oceanic and Atmospheric Administration.