BY LORRY HEVERLY
Special to The Miami Herald

ST. THOMAS, U.S.V.I. -- The U.S. Virgin Islands, best known as a popular port-of-call for cruise lines, usually doesn't top the list as a dive destination. While duty free shopping may be a St. Thomas's claim to fame, undiscovered diving along canyon walls and colorful reefs happens to be St. Croix's best kept secret. Until now.

St. Croix has it all: shore diving, pier dives, dramatic walls, canyons and sea mounts, exploding in a rainbow of coral. Wrecks and shore dives add a dimension of diversity. Divers will encounter plenty of marine life, large and small. The island boasts more than 35 different dive sites, but every dive shop has its own secret spot not found on a map.

Off the walls

Most diving takes place on sites along the north shore on walls running east and west of Salt River National Park. More sites are found in the calm waters around the West End. The best wall diving on St. Croix stems from both sides of Salt River Canyon National Park.

The most dramatic dive site on the island is the West Wall. Eons ago, a waterfall cascaded into Salt River Canyon, cutting into the rock and corals creating gigantic pinnacles, swim-throughs and ledges. Divers will be fascinated by the Technicolor maze and unique topography of this wall, where turtles, large schools of grunts, snapper and Creole wrasse linger in the shallows.

Other sites worth exploring around Salt River Canyon include Shark Shanty, a football-shaped trench housing an aquarium of reef fish and ledges frequented by crab, eels, occasional nurse sharks and a resident turtle. Anchor Dive Center is the only dive shop in Salt River National Park with five-minute boat dives to excellent wall dives and other sites. Shore diving is popular off Cane Bay Beach.

It's a short swim out to the mooring buoy where a spectacular wall begins in 25 feet of water and rolls into an angled drop-off, plunging into the deep. Fed by nutrient-rich waters, the wall is covered in corals, and sightings of turtles, grouper and reef fish keep divers entertained throughout the dive.

Off shore

Besides sites along Cane Bay Wall, there is shore diving at nearby Davis Bay, North Star and Twin Palms.

Cane Bay Dive Shop is conveniently located at Cane Bay Beach, offering guided beach dives, transfers to other shore-accessible locations and guided boat dives to a dozen area sites.

Lurking under shadowy Frederiksted Pier is a spectacular concentration of marine critters. It is an easy giant stride entry off the pier and into 20 feet of water. Bottom times of an hour or longer give divers plenty of time to search for a variety of fascinating marine life.

Pylons are encrusted in a canvas of red, orange and yellow hard corals with bursts of small anemone. Look closely for resident sea horses. Schools of small reef fish congregate in the shade. Eels, octopus and small crabs hide in piles of debris. Sting rays and peacock flounder glides along the bottom while a comical shortnose batfish hops along the sand.

Diving conditions here are ideal for novice and beginner divers.

For a completely different experience, a night dive on the pier is exceptional.

Scubawest Dive Shop is across the road from the pier. Tanks and gear are trucked onto the pier for convenient diving.

Butler does it

Just north of Frederiksted is a cluster of wrecks in Butler Bay. Three wrecks, lying in around 50 to 60 feet of water, can be explored on a one-tank dive.

The 144-foot Suffolk Maid, a sea trawler beached during a hurricane, was towed to the bay where it now rests upright. To the east is the 75-foot ocean tug Northwind, ideal for photographers since the wheelhouse rests in 15 feet. It is entirely encrusted with sponges and marine growth and Queen Angelfish, yellow snappers and lobster are common sightings here.

There isn't much growth on the Virgin Islander, but sting rays are often spotted around the stern of the 300-foot barge. The bonus on this wreck tour is the underwater habitat, once used by NOAA to study long term effects of hyperbaric pressure on divers.