Overfishing has depleted major populations of cod, swordfish, tuna, snapper, grouper and sharks. Instead of sensibly living off nature's interest, many fisheries have mined the wild capital, and famous fishing banks lie bankrupt, including the revered cod grounds of New England and Atlantic Canada. Government-subsidized shipbuilders and fleets drive much of the overfishing. Most ocean pollution doesn't come from ships. It comes from land.
Gravity is the sea's enemy.
Silt running off dirt roads and clear-cut forest land ruins coral reefs and U.S. salmon rivers. Pesticides and other toxics sprayed into the air and washed into rivers find the ocean. The biggest sources of coastal pollution are waste from farm animals, fertilizers and human sewage. They can spawn red tides and other harmful algal blooms that rob oxygen from the water, killing sea life. Improving sewage treatment and cleaning up the runoff from farms will be increasingly vital to preserving coastal water quality.