Human activities are taking a "terrible toll" on the world's oceans and seas, UN Secretary-General Ban Ki-moon warned today in a message marking the first United Nations World Oceans Day.

Oceans provide 97.5 percent of the Earth's water and cover 70 percent of the planet's surface. Oceans generate most of the oxygen humans and animals breathe, regulates the climate and offers an array of foods and medicines. But a rising tide of marine litter is harming oceans and beaches worldwide, says a new report released today by the UN Environment Programme and Ocean Conservancy.

The first attempt to take stock of the marine litter situation in the 12 major regional seas around the world finds that cigarettes and plastic ?especially plastic bags and PET bottles ?is the most pervasive type of marine litter around the world.

Plastics can be mistaken as food by marine mammals, birds, fish and turtles. Sea turtles, in particular, may confuse floating plastic bags with jellyfish, one of their favorite foods.

A five-year survey of fulmars found in the North Sea region found that 95 percent of these seabirds had plastic in their stomachs. Cigarette filters, tobacco packets and cigar tips make up 40 percent of all marine litter in the Mediterranean, while in Ecuador smoking-related rubbish accounted for over half of the total coastal litter in 2005.

"World Ocean Day was established by the United Nations to help create awareness about our seas, their importance to people, and the growing threats they face," said Lynne Hale, director of The Nature Conservancy's global marine program.

The Nature Conservancy suggests:

1. Reduce plastic consumption with reusable shopping bags, water bottles and utensils.
2. Make informed seafood choices. Keep a copy of the Monterey Bay Aquarium's seafood guide in your wallet or text Blue Ocean's FishPhone to help you choose sustainable seafood at the grocery store or a restaurant.
3. Dispose of chemicals properly. Never pour chemicals, pharmaceuticals, oil or paint into the drain or toilets. Check with your county's household hazardous waste program to properly dispose of or recycle chemicals and keep them out of rivers and oceans.
4. Choose green detergents and household cleaners.
5. Get the dirt on your beachside retreat. Before you stay in a hotel on the coast, ask staff what happens to their sewage and swimming pool water, and if they source their restaurant fish from sustainable sources.
6. Find out the source of your food. Buying local, organic food reduces your carbon footprint, supports the local economy and reduces the amount of pesticides and fertilizers can run off into rivers and oceans.
7. Fill your yard with native species. Reducing the amount of grass in your lawn by planting native shrubs and flower beds will provide a better habitat for birds and other wildlife and require less water and fertilizer, which can run off into into rivers and oceans.
8. Keep your beach visit clean. Stay off fragile sand dunes, take your trash with you and leave plants, birds and wildlife for everyone to enjoy.
9. Choose alternatives to coral when shopping for jewelry, household decor or accessories for fish tanks.
10. Celebrate our oceans.