Virgin Islands National Park

   One of the best spots in the National Park System for beginners is Virgin Islands National Park on the Caribbean island of St. John, site of one of the world's first underwater snorkel trails. The self-guided trail in Trunk Bay is in well-protected water 15 feet deep or less. Unfortunately, the popularity of the Trunk Bay trail has led to tremendous damage to the reefs by careless snorkelers. So after a little practice in the bay, most new divers will want to venture onto less-visited reefs with healthier coral growth and a greater variety of plant and animal life. A few notable spots accessible from the beach include Waterlemon Cay, Haulover Bay, Saltpond Bay, and Tektite. Concessioners at the park offer boat trips to outer reefs where the human presence is even less evident. For information, contact park headquarters at 809-776-6201.

   Sadly, the rapid pace of development on St. John outside of the park boundaries also poses a continuing threat to the health of the reefs. The island is steeply sloped, and construction exposes soil to the effects of erosion. Silt smothers the reefs and grass beds that serve as breeding habitat for many fish, crustaceans, and other sea creatures. The park is also a popular stop for boats, from small sailboats to huge cruise ships, and careless anchoring practices have destroyed many acres of reef.

Buck Island Reef

   Another great spot not far from St. John is the 880-acre Buck Island Reef National Monument, which is six miles off the island of St. Croix. The reefs surrounding Buck Island feature vast stands of elkhorn coral, branching out and reaching as high as 40 feet in places. Although the reef suffered severe damage in Hurricane Hugo in 1989, the monument still offers plenty to see.

   The uninhabited island is an important nesting area for three endangered species of sea turtles—hawksbill, green, and leatherback. Adult and juvenile turtles are frequently spotted grazing around the reefs. Buck Island also offers a marked underwater trail in a sheltered lagoon that is ideal for beginning snorkelers. With the monument accessible only by boat, six concessioners operating out of Christiansted, St. Croix, offer half- and full-day trips. Contact monument headquarters at 809-773-1460 for information.

Dry Tortugas National Park

   Closer to the U.S. mainland is Dry Tortugas National Park, composed of seven small islands and 67,000 acres underwater. The park is at the westernmost edge of the Florida Keys about 70 miles from Key West. Because of their remote location, the islands have the most pristine reefs in North America. Although only 40,000 people visit the park each year, park managers are concerned about the growing number of cruise ships that pay a port call to Key West and organize day trips to the Dry Tortugas.

   In addition to the spectacular reefs, the park has a couple of human-made submerged structures that make for exciting snorkeling. A three-masted, iron-hulled sailing ship that wrecked on Loggerhead Reef in 1901 is the first popular spot. The ship has become an artificial reef, attracting a wide variety of marine life. Water depths range from zero, where the wreck breaks the surface, to 20 feet at the deepest point. At the second spot, many snorkelers also enjoy a nighttime dive in the sheltered water of the moat that surrounds the fort. The underwater world changes dramatically when the sun goes down, as nocturnal creatures venture out in search of food. Bring a strong dive light and prepare to enter another world.

   Visitors come to the Dry Tortugas by boat and seaplane out of Key West. Day trips and some overnight trips are available by boat. The only accommodations in the park are a small number of primitive campsites. For more information, contact the park at 305-242-7700.

Biscayne National Park

   Biscayne National Park, located between the Florida mainland and the northern point of the Florida Keys, is even more accessible for U.S. mainlanders than Dry Tortugas. In addition to some spectacular hard coral formations, the reefs in Biscayne have especially abundant soft corals. Giant sponges and sea fans of many shapes and colors attract a variety of marine life.
The snorkeling sites are accessible only by boat. The concessioner, who leaves from the Convoy Point Visitor Center daily at 1:30 p.m., can be reached at 305-230-1144. Reef trips are conducted only in good weather from May to October. Other times, snorkelers are taken to the mangroves inside Biscayne Bay. Many juvenile fish live in the protection of the entangled underwater roots of the mangroves until they are large enough to venture out to the reefs.

   The water quality in Biscayne National Park is quite good, but the heavy boat and ship traffic in the area poses a constant threat to the reefs. A small boat going aground can do tremendous damage to a coral reef, and a collision with a large ship, as happens with disturbing frequency, can be devastating.

   The coral in Biscayne and the Caribbean parks is also subject to bouts of coral "bleaching," a condition that seems related to a rise in water temperature. When the water reaches a certain temperature, the coral expels the colored algae that it depends on for food. Short bleaching incidents do not seem to affect the coral's health, but park biologists worry about the long-term impact as the frequency of bleaching increases.

   Daniel Lenihan and John D. Brooks, who work with the National Park Service Submerged Cultural Resources Unit and are co-authors of Underwater Wonders of the National Parks, also recommend the snorkeling opportunities in a pair of far-flung parks—War in the Pacific National Historical Park on the island of Guam (671-477-9362) and National Park of American Samoa (011-684-633-7082). Both offer excellent snorkeling.

   Visitors to any of these parks should remember that coral reefs are extremely fragile environments where human impacts take a heavy toll. Corals exist only in a tight range of environmental conditions and, when the coral is killed, the huge array of other creatures and plants that exist with it lose their habitat. Lenihan, Brooks, and other Park Service officials from these watery parks hope that each visitor will become an advocate for conservation and the stringent controls needed to preserve these underwater wonders.

Snorkeling Tips    Underwater Wonders of the National Parks, published in 1998, is an indispensable resource for anyone considering a snorkeling trip. Written by Daniel Lenihan, director of the NPS Submerged Cultural Resource Unit, and John D. Brooks, an underwater photographer with the unit, the book details the watery wonders of the park system, from the coral reefs of the Caribbean to the icebergs in Alaska.    The two have gone snorkeling and scuba diving at every park mentioned in the book and include detailed suggestions on where to go, how to get there, and what you might find. They also have some sound advice for making your snorkeling excursion more enjoyable and helping to protect the fragile reef environment, including these tips: Do not touch the animals. Even a gentle caress can disturb the mucous coating that helps protects fish from disease. Do not feed the fish. If fed by humans, after a while they become dependent on handouts and lose the ability to forage. Also, they lose their natural wariness, which makes them easy prey for poachers. Even though harvesting fish for tropical collectors is illegal in the national parks, it still goes on. Do not touch the coral. The tiny jelly-like polyps that live inside the hard calcium casing are fragile. One swipe of the hand can kill hundreds of them. Many popular shallow reefs have been decimated by careless swimmers who stand on them when they get tired. Swim gently and avoid kicking up a lot of sand when near a reef. The sediment can eventually smother the coral and block vital sunlight. Wear a liberal coating of waterproof sunscreen on your back and the backs of your legs. The thin film of water over you acts as a magnifier and because the water keeps your skin cool, you may not realize your skin is burning until it is too late. People who are especially sun-sensitive should wear a covering. Keep an eye out for stinging organisms like jellyfish and fire coral. Do not reach into holes or crevices in the reef. They could turn out to be the lair of a moray eel. Take off your jewelry. While barracuda attacks are almost unheard of, the toothy fish do seem to be attracted to shiny objects. Shark spottings are rare on the shallow reefs that snorkelers frequent, but if you see a shark, do not panic. Most reef sharks are passive types, not man eaters, and they usually ignore swimmers. If one acts aggressively or pays undue attention to you, calmly and slowly leave the water. Do not walk in shallow water near the reef; sea urchin spines can cause nasty puncture wounds to the bottom of your feet. Shuffle your feet across the bottom as you wade through the shallow sandy areas on your way to and from the reef. Stingrays lying on the bottom will swim off if you bump into them but sometimes sting when they are stepped on. Be aware of currents. Unless you plan to do a "drift dive" where you start in one spot and let the current carry you to an exit point, it's usually best to swim into the current first and then let it carry you back at the end of your dive when you are most tired. –EH