Crossing into Costa Rica's paradise

A dozen adults gathered on the upper deck of the M/V Argo, straining at the railing of the boat like children at an FAO Schwarz window. After more than 30 hours of travel through open ocean, we'd finally reached land. The sun was rising over Cocos Island, nearly 350 miles off the Pacific coast of Costa Rica, revealing tumbling waterfalls and deeply green hillsides. Frigate birds and brown boobies swooped and called in what we all interpreted as a welcome to their haven.

When Jacques Cousteau first saw Cocos, he called it "the most beautiful island in the world." Like so many treasures, pirates claimed Cocos Island as their own -- first as a life-saving source of fresh water and wood for ship repairs, then as a bank. Many believe that hundreds of tons of gold, religious artifacts and other riches worth billions of dollars by today's standards were hidden on the island by pirates.

Through the years, hundreds of hopefuls have tried to unearth this loot, including a German named August Gissler who spent more than 19 years treasure-hunting on Cocos. Between 1889 and 1908 Gissler managed to find only a handful of coins, but that was enough to keep the allure alive. Treasure-hunting expeditions are still being organized, though a permit from the Costa Rican government is now required.

Pirates maintained their unofficial ownership of Cocos Island until 1832, when Costa Rica claimed the land. Cocos Island National Park was created in 1978 and UNESCO named the area a World Heritage Site in 1997.

The area's rich waters and the rocky outcrop's remoteness, jagged angles, 300 waterfalls and deep green lushness have inspired others beyond Cousteau and pirates.

President Franklin Roosevelt made three trips to Cocos Island. In 1935, during his first visit, he caught a 110-pound sailfish. The fish was shipped back to the United States, where the avid fisherman had it mounted and hung in the White House.

Staffers aboard the Argo, my home during a week of diving and island exploration, pointed out one particularly elegant waterfall, which, they said, appears in the opening scenes of the original "Jurassic Park" blockbuster. Robert Louis Stevenson's "Treasure Island" also may have been set on Cocos Island.

Underwater treasures

An even greater number of species take refuge in the waters around Cocos Island, which is sometimes called Shark Island because of the dense concentrations of tiger sharks, silky sharks, scalloped hammerhead sharks, enormous manta rays, reef sharks, Galapagos sharks and even whale sharks.

Those lucky enough to dive around Cocos are virtually guaranteed close encounters with all of these exciting sea creatures. I spent time underwater with hundreds of hammerheads, enormous rays, jittery reef sharks, beefy tigers, sleek silkies and lumbering Galapagos sharks, all at close range. Though manta rays and whale sharks were seen by other divers in my group, they eluded me (this time).

Sharks are drawn to this area because of unique mini mountains on the sea floor called the Las Gemelas seamounts. When deep currents hit these seamounts, nutrient-rich water is pushed toward the surface, attracting schools of fish and the predators who love them. Fishermen favor the area for the very same reason. Fishing is banned within 12 nautical miles of Cocos Island, but the seamounts lie outside that restricted zone and fishermen ply the waters for lucrative tuna and shark fins.

Scalloped hammerheads, listed as endangered by the International Union for the Conservation of Nature (IUCN), are often targeted for their valuable fins. Leatherback turtles, listed as critically endangered by the IUCN and whose numbers have plummeted by 90 percent in Costa Rica over the past 20 years, are accidentally captured and drowned in nets. While the Las Gemelas seamounts have been fished with lines, the area has never been trawled, so the habitat is still fairly unspoiled. Marine biologist and ocean explorer Sylvia Earle calls areas like these "hope spots" because they represent places where we can hope to see improvement in the ecosystem if it can be protected.

Costa Rica, an early adopter of green policies and ecotourism, had officially protected a quarter of its land but only 1 percent of its oceans. That changed in March 2011 when, after six years of planning, President Laura Chinchilla Miranda created Costa Rica's Seamounts Marine Management Area, increasing the existing Cocos Island protected zone fivefold. The area now includes 2 million acres or nearly 4,000 square miles. It's larger than Yellowstone National Park and is the second-largest marine protected area in the region after Galapagos National Park.

Still, environmentalists are concerned about enforcement of regulations over such a vast area. Daily patrol responsibilities lie with the nine rangers assigned to Cocos Island National Park and their three small patrol boats. It's an impossible task, and the fishermen know it.

A shed full of contraband

Inside an enormous shed near the ranger station on Cocos Island, I found bags full of fishing line stacked to the rafters. Fifty-five-gallon drums filled with huge steel hooks lined the walls. Any remaining space was stuffed with buoys. Rangers explained that the fishing gear had been collected over the previous two months and represented just a fraction of the illegal fishing activity going on around the island. Rangers believe fishermen cut their lines and dump their gear overboard if they suspect there's a patrol in the area. Under current regulations, unless fishermen are found with gear in the water in active use, they can't be arrested.

During a dive at a site called Dirty Rock, our group found ample evidence of this practice. Just a few minutes into the dive, we discovered a section of the rock draped with hundreds of feet of line, studded with massive hooks. We spent most of the dive carefully removing the line and hooks, which we then brought to the surface and added to the collection in the rangers' shed.

But the presence of tourists also does some good. In 2011, 3,528 people visited Cocos Island National Park, each paying a daily $32 national park fee. The mere presence of the live-aboard dive boats, on which most visitors arrive, and their small zodiacs used to get to dive sites acts as an additional patrol fleet, further deterring would-be fishermen.

For the last dive of my trip, our group returned to Dirty Rock, descending to a cleaning station at nearly 90 feet. Sharks regularly cruise through these spots where cleaner fish congregate, ready to gently remove parasites from the predators' skin. As we settled in, the hammerheads slowly overcame some of their natural shyness. We floated motionless and mesmerized for nearly half an hour as more than 25 hammerheads ventured closer and closer until they were near enough to make eye contact before gliding away. It felt like they were saying goodbye. And thank you.