Where's Teddy Roosevelt when we need him? Nearly a century ago, President Theodore Roosevelt showed his passion for the outdoors and his vision for the future by preserving millions of acres of wild land as national forests and parks for the benefit of all Americans. He made science the basis of land management and turned back the tide of rapacious short-term exploitation.

Now such a tide besets our oceans. Populations of some important species, such as tuna, swordfish and shark, have been reduced by 90 percent. Agricultural chemicals flowing downstream have created a dead zone the size of New Jersey in the Gulf of Mexico and similar voids in bays nationwide. Coastal waters and communities suffer from pollution and habitat loss. Economies dependent on fishing, recreation and tourism are put at risk.

A 21st-century president can do for the oceans what Roosevelt did on land. This month President Bush is to receive the report of the U.S. Commission on Ocean Policy, the body he appointed to conduct a study of the state of the seas. Its key findings echo those of the independent Pew Oceans Commission, and they chart a course for recovery. Both the president and Democratic challenger John Kerry should take these findings seriously and pledge to steer such a course.

What can a president do? First, make science the basis of ocean management. Sensible coordination of the myriad laws and agencies responsible for ocean protection could bring order and effectiveness to today's dizzying bureaucracy. Much as Roosevelt sought the greatest good for the greatest number over the long run, regulators can use modern market-based methods to give fishermen a long-term stake in the recovery of major fisheries.

Some government regulators, pressured by the short-term economics of the industry, haven't seen the oceans for the fish. They set higher catch limits than are justified by science and enforce them with ever-shorter fishing seasons that distort the market and make fishermen compete in dangerous and crowded conditions.

Fortunately, many fishermen have come around to a long-term view. The Alaska halibut fishery, which faced a crisis in the 1990s, is thriving again thanks to a quota system by which each fisherman is assigned a percentage share of the scientifically determined total allowable catch. Gone are the perilous short seasons; now boats can go out whenever they choose, supplying a profitable year-round market for fresh fish. As the fishery continues to recover, the allowable catch will increase and so will the fishermen's guaranteed stake. Such proven quota-based methods should be expanded elsewhere.

Second, just as Roosevelt expanded the area protected in national parks, an oceans president should expand the marine protected areas that are critical for recovery. These include nurseries and spawning grounds -- the ocean's cradles of life. Today only 1 percent of our ocean waters are protected. But there is hope. For example, Bush has supported the process to establish the 1,200-mile ecosystem reserve started by President Bill Clinton in the Northwestern Hawaiian Islands, comprising up to 70 percent of America's coral reefs.

Third, an oceans president can use the bully pulpit of the White House to spur change in wasteful fishing practices that kill fish indiscriminately and destroy marine habitat and breeding grounds. By championing needed legislation, such a president can protect our ocean resources as effectively as the national parks have protected cherished lands.

The oceans face some challenges that had no parallel in Roosevelt's day, and these must be met with equal vigor and intensity. Science magazine reported last month that the oceans have been doing the world a favor by absorbing nearly half the global warming gases emitted by human activities. But this capacity is limited, and even at the present rate, the researchers found that marine life will suffer as the absorbed gases change the oceans' chemistry. Rachel Carson once wrote, "There has long been a belief that the sea, at least, was inviolate, beyond man's ability to change and to despoil. But this belief, unfortunately, has proved to be naive." Indeed we did not know our own strength. Yet neither should we underestimate our power to alter course. The oceans are surprisingly resilient and, given the chance, much of the harm can be reversed.

A president who chooses to follow in Roosevelt's footsteps to save our seas will long be remembered.

Fred Krupp is president of Environmental Defense. Peter Benchley is an author and ocean conservationist.