The noble notion that marine parks can save our favorite parts of the sea has gained momentum in recent decades. Key Largo's John Pennekamp Coral Reef Marine Park was founded in 1960 and many others soon followed. Dozens were established around the world in the mid-1970s and now there are more than 200 in the Caribbean alone. These parks, preserves, refuges and sanctuaries are protecting our best dive sites for future generations, right? Not necessarily. Like many complex issues, this question has no simple answer. In the United States, a ''marine sanctuary'' is not a place of complete safety as the name might imply. The terminology was chosen primarily to differentiate areas managed by the National Oceanic and Atmospheric Administration (NOAA) from those overseen by the National Park Service. Whether it's called a sanctuary or a park, most protected marine areas allow a variety of activities within their boundaries. Divers share them with sport and commercial fishermen, boaters, surfers, commercial shipping and the military. Treasure hunters, tropical fish collectors and miners may even be allowed to join the party. So what's the difference between a marine park and the rest of the ocean? Generally, marine parks prohibit only the most potentially damaging activities, such as oil extraction and dumping. Other activities like diving, boating and fishing are regulated in hopes of preventing long-term degradation of natural resources and avoiding conflicts among users. The Achilles heel for many marine parks is the compromises involved in meeting these divergent objectives. No Magic WandsAn old sailor's joke defines the equator as the line that separates the north danger zone from the south danger zone. It's a sadly accurate description for marine parks around the world that face a host of dangers ranging from changes in the global climate, storms and pollution to overfishing and damage caused by ship groundings, anchors and divers. Do we expect too much from our marine parks? Lots of happy faces beam at the dedication of a new park, but few realize that it's no guarantee of perfect preservation. For example, marine park managers have no magic wand to reverse the devastation caused by storms. When a hurricane hits the Bahamas or a typhoon blows through the Philippines, shallow coral reefs take a beating, park or no park. Marine parks are also largely unable to stem the tide of natural phenomena, such as coral bleaching. Consider the problem in Australia posed by the coral-eating crown of thorns starfish. After years trying various techniques, from poison to wholesale removal, to contain these creatures in the Great Barrier Reef Marine Park, researchers concluded that it is best to let nature take its course. Unfortunately, this approach offers little comfort for dive operators in the southern Red Sea, where large sections of reefs have been hit hard by the same starfish. The mass mortality of long-spined sea urchins in the Caribbean in the 1980s is another example of environmental damage that didn't stop at park boundaries. The good news is that the urchins appear to be mounting a comeback. Research conducted in parks is helping managers understand some of these problems, but for the most part all they can do is stand by and hope that the reefs repair themselves as they have done in the past. Enforcing The RulesMany marine parks also are ineffective in preventing overfishing. In some parts of the world, subsistence fishermen strip the reefs clean simply trying to keep their families alive. Other areas suffer from the exceptional efficiency of modern gear or the extravagant waste of discarded ''bycatch.'' Would stricter enforcement help? Certainly, but think about this next time you see a marine park ranger: less than half of their time is spent actually watching over the park. The remainder of the day is devoted to boat maintenance, record keeping, court appearances, training and general administrative chores. Another problem lies in the most basic difference between marine parks and terrestrial parks: no fences. The borders of nearly all marine parks are open. People and fish come and go 24 hours a day, along with anything that might be suspended in, or floating on, the water. Plastic trash, storm runoff and other pollutants continuously flow in from outside the park. Park officials have little enough clout inside their boundaries. Outside, there has to be a smoking gun in order for managers to take action, like a grounded oil tanker leaking oil with photos showing the spill flowing from point A to point B. Graeme Kelleher, former chairman of the Great Barrier Reef Marine Park Authority, was always quick to point out that a park's regulations against spilling oil would not make the damage any less severe if a spill did occur. Unless cleanup equipment is on the spot and the weather cooperates, the reaction to a spill is more damage assessment than damage prevention. The fact that a marine park exists doesn't eliminate spills and groundings, but parks can reduce the potential for such incidents by making the financial penalties high enough to ensure extra vigilance. The owners of the freighter Wellwood paid more than $6 million in fines after their ship flattened nearly 10 percent of the coral at Molasses Reef in the Key Largo National Marine Sanctuary in 1984. When the money is used to restore or manage the park's resources, big fines can help a lot. Success StoriesMarine parks are best at preventing the kind of direct damage caused by boats, bulldozers and the hands of man. A few of the many noteworthy successes include:
- Without Pennekamp Park's ban on collecting coral, entire reefs would have been sold piece by piece at roadside stands along the Overseas Highway in the Florida Keys in the 1960s.
- By prohibiting bottom trawling in the Great Barrier Reef Marine Park back in the 1970s, officials preserved countless acres of critical habitat.
- Thanks to the creation of the Monterey Bay National Marine Sanctuary in California, more than 5,000 square miles of ocean will remain unblemished by oil rigs.
- In the British Virgin Islands, thousands of divers enjoy visiting the historic wreck of the RMS Rhone, thanks to the staff of the marine park that watches over it.St. Vincent and the Grenadines have prevented development from altering the shallow reefs and sandy beaches of the Tobago Cays National Marine Park.
- New Zealand preserved the natural setting of the Kermadec Islands by establishing a marine reserve 400 miles from Auckland in 1990.
Thanks to changes in diver training and awareness over the last few decades, today's divers cause significantly less damage than we did in the past. Awareness programs adopted by dive certification agencies and the educational efforts of marine parks have taught us a kinder, gentler dive etiquette. Most of our impact now comes from sheer numbers of visitors in popular marine parks. Each of us causes little damage, but the effect is cumulative. Like too many people walking the same paths across a lawn, we eventually wear the lush green down to brown.