At the lonely center of the North Pacific Ocean, farther from just about everything than just about anywhere, lies Midway Atoll. I've come with Canadian writer Nancy Baron to the world's largest Laysan albatross colony — 400,000 exquisite masters of the air — a feathered nation convened to breed, cramming an isle a mile by two.

Ravenous, goose-size chicks so jam the landscape that it resembles a poultry farm. Many have waited more than a week for a meal, while both parents forage the ocean's vast expanse. An adult glides in on 7-ft. (2-m) wings. After flying perhaps 2,000 miles (3,200 km) non-stop to return here, in 10 minutes she will be gone again, searching for more food. She surveys the scene through lovely dark pastel-shadowed eyes, then calls, "Eh-eh-eh." Every nearby chick answers, but she recognizes her own chick's voice and weaves toward it.

Aggressive with hunger, the whining chick bites its parent's bill to stimulate her into regurgitating her payload. The adult hunches, retching, pumping out fish eggs and several squid. The chick swallows in seconds what its parent logged 4,000 miles (6,400 km) to get. The chick begs for more. The adult arches her neck and retches again. Nothing comes. We whisper, "What's wrong?" Slowly comes the surreal sight of a green plastic toothbrush emerging from the bird's gullet. With her neck arched, the mother cannot fully pass the straight brush. She tries several times to disgorge it, but can't. Nancy and I can hardly bear this. The albatross reswallows and, with the brush stuck inside, wanders away.

In the world in which albatrosses originated, the birds swallowed pieces of floating pumice for the fish eggs stuck to them. Albatrosses transferred this survival strategy to toothbrushes, bottle caps, nylon netting, toys and other floating junk. Where chicks die, a pile of colorful plastic particles that used to be in their stomachs often marks their graves.

Through the intimate bond between parent and offspring flows the continuity of life itself. That our human trash stream crosses even this sacred bond is evidence of a world wounded and out of round, its relationships disfigured. The albatross's message: consumer culture permeates every watery point on the compass. From sun-bleached coral reefs to icy polar waters, no place, no creature, remains apart.

If albatrosses' eating plastic seems surprising, so do many of the oceans' problems. Like elusive fish, facts often defy common perceptions. Examples: Most people think oil spills cause the most harm to ocean life. They don't. Fishing does. When a tanker wrecks, news crews flock to film gooey beaches and dying animals. Journalists rush right past the picturesque fishing boats whose huge nets and 1,000-hook long-lines wreak far more havoc on the marine world than spilled oil.

Fishing annually extracts more than 80 million tons of sea creatures worldwide. An additional 20 million tons of unwanted fish, seabirds, marine mammals and turtles get thrown overboard, dead. 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.

Enforcing fishing limits-to give the most devastated fish populations a chance to rebuild—could ultimately enable us to catch at least 10 million more tons of sea life than we do now. Government-subsidized shipbuilders and fleets drive much of the overfishing. Eliminating those subsidies—as New Zealand has already done—would mean paying less to get more in the long run. 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. (Midway's albatrosses have in their tissues as much of the industrial chemicals called pcbs as do Great Lakes bald eagles.) 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. The Mississippi River, whose fine heartland silt once built fertile delta wetlands, now builds in the Gulf of Mexico a spreading dead zone—almost devoid of marine life—the size of New Jersey. Improving sewage treatment and cleaning up the runoff from farms will be increasingly vital to preserving coastal water quality.

Fish farming—aquaculture—doesn't take pressure off wild fish. Many farms use large numbers of cheap, wild-caught fish as feed to raise fewer shrimp and fish of more lucrative varieties. And industrial-scale fish— and shrimp-aquaculture operations sometimes damage the coastlines where the facilities are located. The farms can foul the water, destroy mangroves and marshes, drive local fishers out of business and serve as breeding grounds for fish diseases. In places such as Bangladesh, Thailand and India, which grow shrimp mainly for export to richer countries, diseases and pollution usually limit a farm's life to 10 years. The companies then move and start again.