When Howard Hall graduated from college in California, he had a degree in zoology and a love of scuba diving. These days, he’s managed to combine the two interests into a successful career. NATURE spoke with Hall, one of the filmmakers behind Shark Mountain, a documentary about the abundant sea life around Cocos Island, in the Pacific Ocean off Costa Rica in November 2004.

How did you get into this line of work?

I started as a sport diving instructor when I was in college, where I got a degree in zoology. Then, I began looking for ways to make a living with my skills, and underwater photography seemed like a good one. It slowly evolved into a career.

Underwater filmmaking has seen some big advances in technology.

Yes, the technology both for diving and cameras has changed dramatically. In diving, we’re now using closed circuit mixed gas re-breathers that allow us to stay down longer and deeper. And we’ve switched to high definition cameras with lenses that do nearly everything, so we don’t have to change lenses anymore. Having said all that, however, I’m finding that it is harder to get the sequences I want for my films, simply because there are so many fewer animals now. So the technology is better, but the populations and ecosystems are declining.

Filmmaker and diver Howard Hall

Do you think your films can help reverse that decline?

There’s been a long controversy over whether conservation films do any good. But I know for a fact that the films we’ve shot at Cocos Island helped convince the Costa Rican government to ban the finning of sharks and take other conservation measures. Unfortunately, those laws aren’t always enforced. But the awareness is growing.

How did you find out about Cocos Island?

A friend of mine put in the first live aboard dive boat there, and invited me down on one of their first trips, back in about 1990. It was remarkable. [Since then,] we’ve made 3 films there, including an IMAX film that included 135 days of diving. So I’ve seen it change over a 15-year period, but it can be hard to track the changes. Some are due to natural fluctuations that happen over long time periods. Still, my impression is that there is less of everything now. In places where you once saw lots of hammerhead [sharks], you may not see a single hammerhead.

That makes some sense, because sharks are being fished all along South and Central America. But there are also fewer small animals, like jawfish and blennies, and it’s hard to explain why. Cocos is not unusual in that regard — every place I go I see less animals. There are some exceptions, but the general trend is to see less animals.

What are some of your favorite shots?

I’ve never gotten tired of filming the clouds of schooling hammerheads. That is one of the most amazing things you will ever see. Every time I shoot it I try to do it a little better. But it is hard to get a great shot, because [the waters around] Cocos can be dark and murky and every year there seem to be less sharks.

Any other sequence you are still looking to get?

A long while ago, I was diving and there were white tip reef sharks being cleaned by gobies. I went down, lay down beside them, and shot the little gobies swimming all over the place — in the sharks’ mouth, their gills. It was remarkable. Since that day, I’ve gone back to that same rock over and over again and never been able to shoot that sequence again. It’s been hugely frustrating! A lot of people assume that shooting the big animals — sharks, whales, dolphins — is the best thing about underwater work. But I almost prefer shooting the small animals. When you set up a camera and watch a small animal for a long time, you often catch behavior people know nothing about. There are many cases where we’ve learned entirely new things about fish. And some things that the experts said couldn’t happen, but did!

What’s next?

We’ll soon be shooting off the California coast for an IMAX 3D film about biodiversity in our world’s oceans. It’s mostly an animal behavior film, looking at the weird and interesting behaviors of some of these animals. It requires an IMAX camera in a housing that weighs 1500 pounds. But it’s a great project.

Good luck!

Thanks. It’s going to be a huge task that’s going to take a year or more.

“It’s the most awesome thing I’ve ever seen.” That is how K. Michael Garman, a cave diver and researcher featured on NATURE’s Springs Eternal, describes the Dragon’s Lair, an unusual cavern he is studying in Crystal Beach Spring on Florida’s west coast.

As Springs Eternal shows, the Dragon’s Lair gets its name from a remarkable layer of bacteria that grows suspended in the water, lying like a smoky cloud between a heavier layer of salty water and a lighter layer of fresh water. “Some days it is thin and wispy, other days it’s thick and looks like solid bottom,” says Garman, who has probed the Lair’s depths dozens of times along with his wife Sherry and other divers. But the cloud never ceases to enthrall him, he says. “Every time I turn the corner [into the Lair], I’m afraid it will be gone,” he says.

Exploring in the dark can be perilous.

Getting into the cavern network is no easy task, as Springs Eternal illustrates. Unlike most Florida springs, which exit on land, Crystal Beach Spring emerges from the seafloor of the Gulf of Mexico. To enter, divers must go offshore and swim down to the entrance, a narrow, rubble-filled hole barely big enough to squeeze through. But by shedding their equipment and dragging it through the opening, the divers are able to enter a mystical — and dark — world.

Garman, however, says the lack of light makes things more interesting. “I’ve never been bored in a cave,” he says. “When you are diving on a reef, you are often looking at just another fish. But in a cave you notice a lot more detail because you are focused narrowly on what your light is showing you.”

In Crystal Beach Spring, he’s found plenty to look at. There are blind crayfish, small crustaceans, and snails. And each room in the maze-like cavern has its own feel. Besides the Dragon’s Lair, for instance, there is Thunder Road, the cave’s main passage, and the Bacteria Room, which earned its name from the orange bacterial and fungal mats that line its nooks and crannies. Eventually, Garman, a graduate student at the University of South Florida, hopes to write a thesis on the cavern’s unusual food web, which is based on the bacteria’s ability to live on sulfur extracted from the sea water.

Such research is not for everyone. Cave diving is a dangerous activity that requires extensive training, Garman notes. New technologies — from brighter lights to more dependable breathing gear — have made the sport safer and easier, he says, but are no substitute for experience and good judgement. “We’ve had things go wrong, such as a light going out, where we’ve called a dive and exited the cave,” he says. “Sometimes, you just have to say: ‘The cave’s going to be here next week, and we can come back.’ It’s just the smart thing to do.”

It’s called “Iron Bottom Sound.” Between 1941 and 1945, this swath of ocean off the South Pacific island of Guadalcanal saw some of the fiercest fighting of World War II, with American and Japanese forces clashing almost daily at times. For some, the name still conjures up memories of pain, bravery, and brushes with death.

Today, however, Iron Bottom Sound is best known as a mecca for scuba divers, who can explore the dozens of war wrecks that litter its bottom. From fighter planes and tanks, to cargo ships and destroyers, Iron Bottom Sound has become a kind of underwater museum. Major wrecks include the American cruiser Quincy, the Australian heavy cruiser Canberra, the Japanese aircraft carrier Kinugasa, and the battleship Kirishima. While most are in water too deep to be visited by recreational divers, more accessible wrecks have helped make the Solomon Islands, where Iron Bottom Sound is located, a world-famous destination for divers.

The Japanese freighter Kasi Maru lies in Iron Bottom Sound.

There are more than 900 islands in the Solomons chain, which stretches for hundreds of miles across the South Pacific. And divers say there are at least as many wrecks. On NATURE’s WAR WRECKS OF THE CORAL SEAS, for instance, viewers visit the Kasi Maru, a Japanese freighter that was strafed and sunk while unloading cargo on the island of Munda. She now sits in 50 feet of water, next to a barge that accompanied her to the bottom.

Not far away, in Rendova lagoon, sits an American Douglas Dauntless dive bomber with a remarkable story. On July 23, 1943, Marine Corps pilot Jim Dougherty and his radio gunner, Robert Bernard, set out to sink Japanese ships that were supplying local troops. As Dougherty swooped low over the island of Munda on a bombing run, flak from several shore guns crippled his plane. Miraculously, he managed to nurse the failing craft back to nearby Rendova, which had been seized by U.S. troops just 2 days before. He then crash-landed in the lagoon, where he and Bernard were rescued. His plane settled into 35 feet of water, never to be seen again — or so he thought.

More than 50 years later, Dougherty got word that divers had rediscovered his plane. And in 1995, the 75-year old former pilot returned to the site of his crash landing. Donning scuba gear, he swam slowly down to the wreck and then sat in the cockpit one last time.

Nearby Gizo island also has sunken treasure. The 450-foot-long Japanese transport Toa Maru, for instance, lies on her starboard side in 40 feet of water. Artifacts are scattered across the seafloor around her, ranging from Saki bottles and small jars to gas masks and cooking gear. Ammunition still lies stacked in her holds, waiting for guns long silenced. One can almost see the chaos that accompanied her sinking.

The Solomon Islands are home to dozens of World War II wrecks.

In waters close by sit the wrecks of two American aircraft that wrought similar havoc. The Hellcat was a nimble dogfighter that held deadly aerial duels with Japanese fighters. The Corsair, with its distinctive bent, gull-shaped wings, was another air combat workhorse. Today, both planes sit quietly on the bottom, their powerful engines mute, their wings covered with sponges and coral.

Such wrecks have become an important mainstay of the Solomons tourism industry. But they also pose threats to the environment. Fifty years after their destruction, some wrecks are beginning to leak oil, imperiling coral reefs and beaches. Some biologists say reefs around Western Guadalcanal are dying from oil pollution. To address the problem, officials have been working on plans to remove oil from some wrecks — without destroying their value as historical sites or memorials to those who once fought fiercely over the South Pacific.

To order a copy of WAR WRECKS OF THE CORAL SEAS, please visit the NATURE Shop.
Online content for WAR WRECKS OF THE CORAL SEAS was originally posted May 2003.

In the clear waters off the coast of North Carolina, the wreck of the submarine “Tarpon” lies broken and battered on the sea floor. The haunting wreck alone is enough to attract divers.

But in recent years, curious throngs have swum down to the site to see something else: sharks. Each spring and autumn, hundreds of Ragged-tooth sharks gather at the wreck to mate, stirring up the sand with the kind of rough-and-tumble courtship rituals seen on The Secret World of Sharks and Rays. Divers even find shark teeth littering the bottom, broken off during mating as the males clasp their jaws around the females. The “Tarpon,” however, is just one destination in the increasingly popular sport of shark diving. Last year alone, researchers estimate more than 200,000 people swam into the deep to feed and commune with schools of small sharks — or climbed into a protective steel cage to get up close and personal with potentially dangerous animals like the Great White shark. Many additional tourists took the safer option of swimming with rays.

“How many of your friends have ever petted a six-foot nurse shark?” asks an advertisement from a California-based shark diving company, one of hundreds that have sprung up in recent years from Australia to the Bahamas. For a fee, this firm and others will put you at the center of swirling schools of sharks ready to eat fish out of your hands. Most companies, however, have trained guides clad in bite-proof suits do the feeding while clients watch and get some close-up pictures. Some guides even use heavy chain-mail protective suits, much like Knights of the Round Table used to wear.

When it comes to rays, however, such protective measures aren’t necessary. In the Bahamas and elsewhere, divers can find themselves amidst a flock of hungry, flapping rays, eager to snatch squid treats from onlookers. Some guides even claim the rays look forward to human visitors and enjoy being petted and stroked.

Sometimes, however, shark diving requires people to huddle behind bars. When the quarry is Great Whites, Tigers, and other potentially deadly sharks, divers often descend to the sharks’ territory in protective cages. At Australia’s legendary “Scuba Zoo” on Flinders Reef in the Coral Sea, for instance, businessman Mike Ball has built a huge 60-foot-long metal cage on the sea floor. While divers feed the area’s many sharks, onlookers can watch the action from inside the cage or, if they dare, from outside the bars. The cage can be surrounded by up to 30 sharks at a time. While some conservationists are concerned that such feeding operations may make wild sharks too dependent on people, many hope the growth of shark diving will make it more valuable to leave sharks in the seas than to kill them.

They note, for instance, that shark diving can help employ small-scale fishermen who now spend their days catching sharks. Already, divers have shown they are willing to spend big bucks on sharks. For instance, it costs more than $3,000 each for the opportunity to swim with giant Whale sharks, and hundreds of dollars to spend a few hours with more common sharks. In the Bahamas alone, more than 20,000 divers participate in shark dives each year. Shark conservationists are hoping that, like bird watchers before them, shark watchers will soon become the vanguard of a movement to protect the world’s imperiled sharks.