This program premiered November 15, 2009.

The Steller’s sea lions that populate the Alaskan coastline are powerful, playful, and sometimes rowdy creatures who bump and jostle each other on land but acquire a sublime gracefulness in the water. They are also the subject of a strange and tragic mystery: Steller’s sea lions are rapidly disappearing from one of the last great wildlife strongholds of the world, and no one knows why.

Naturalist filmmaker Shane Moore, who has been working in the Alaskan wilderness for much of the past 10 years, brings a sense of urgency and new understanding to this puzzle in A Mystery in Alaska.

As scientists and environmentalists race the clock to find answers, pressure has been growing on Alaska’s fishing industry to suspend most of its pollock fishing, on the suspicion that it is robbing Steller’s sea lions of an important source of food. But new research illustrated in this film shows that a broad combination of factors could be responsible for the sea lions’ plight.

To order a copy of A Mystery in Alaska, visit the NATURE Shop.

Online content for A Mystery in Alaska was originally posted May 2003.

Join Hardy Jones in his crusade to protect dolphins in NATURE’s The Dolphin Defender.

Nearly three decades ago, filmmaker Hardy Jones became fascinated by wild dolphins. Even though many said it couldn’t be done, he set out to film these sleek sea mammals in the open ocean. Along the way, he became closely involved with his subjects and came to appreciate dolphins as highly intelligent creatures worthy of careful protection.

Eventually, Jones turned his camera into a tool for conservation. He filmed dramatic dolphin hunts, and the documentary footage made headlines and sparked international protests. Jones also discovered the effects of chemical pollution on dolphins and orcas, the largest species of dolphin. He came to realize that threats to these marine mammals were threats to the ocean itself, and to us all.

Now, in NATURE’s The Dolphin Defender, Jones shares some of his most dramatic and beautiful images, and tells the moving personal story of his journey into the world of dolphins. It is a memorable voyage revealed with the energy and elegance of the dolphins themselves.

To order a copy of The Dolphin Defender, please visit the NATURE Shop.

Online content for The Dolphin Defender was originally posted May 2005.

In the summer of 2003, word got out that fishermen in the Solomon Islands, a tropical chain of islands in the Pacific, had trapped some 200 bottlenose dolphins in a shallow inlet. After securing the animals’ captivity, they began selling them to the highest bidders.

Who were the buyers interested in such cruelly captured creatures? Marine parks that prize the intelligent animals for their ability to perform acrobatic tricks, and hotels and amusement centers that charge guests a hefty fee to “swim with the dolphins.” Like the dolphins captured in Bluefields, Nicaragua in NATURE’s The Dolphin Defender, these animals were destined for hotels. Although the Bluefields dolphins were eventually rescued and released, several dozen of the Solomon dolphins were not as lucky and were flown to tourist hotels in Mexico. The imports drew fierce protests from conservationists and condemnation from Mexican newspaper editors, who said the trade violated international conservation laws. Eventually, the government responded that it would more carefully scrutinize future dolphin imports.

Even today, despite government efforts, “the demand for live dolphins is just exploding,” says Hardy Jones, the filmmaker and dolphin advocate behind The Dolphin Defender. “The trade is being encouraged by people willing to pay $150 each to jump in the water and swim with a captive dolphin for an hour.” For decades, Jones has been working to expose and stop the trade in dolphins which he says contributes to the decline of some species. In Japan, for instance, where dolphin meat is considered a delicacy, the trade is helping bring back another troubling practice: the annual dolphin hunt, which Japanese fishermen largely abandoned in the 1970s after international protests.

Traditionally, the hunts took place in several seaside villages. Fishermen would corral the dolphins into nets or weirs, then kill and butcher them. The meat brings a good price on the Japanese market, and was at one time an important source of income for some families. (Jones says dolphin meat today is contaminated with mercury and other pollutants, and not very safe to eat.)

In 1980, Jones filmed one of the hunts and gave the bloody, dramatic footage to television networks. Many viewers were shocked, and the ensuing protests persuaded many fishermen to abandon the practice. One village eventually established a dolphin-watching industry to help replace lost income.

Scientists rehabilitate a Bluefields dolphin before releasing it back into the wild.

But Jones says the growing dolphin trade, which some analysts estimate involves up to 1,000 animals a year, is encouraging Japanese villagers to bring back the hunt. That’s because they now have two kinds of customers: those interested in buying the meat, and those willing to pay $20,000 or more for a single live dolphin.

“Japan is becoming a major source of dolphins along with China and some other nations,” Jones says. Demand is also coming from Asia, where an economic boom is promoting the growth of tourism. In the United States, dolphin captures are strictly regulated; there have been no legal captures since 1993. Some marine parks have learned to breed dolphins while others display injured animals that are being rehabilitated or import animals from European parks.

In the Solomon Islands, the controversy over the 2003 captures has died down. But some conservationists say an unstable political situation has allowed the trade to continue on a smaller scale.

The protests have had an impact elsewhere. Last year, a dolphin hunter obtained a permit from the government of the Caribbean islands of Antigua and Barbuda to capture a dozen dolphins. After the public found out about the permits, however, protesters convinced officials to change their minds.

by Irene Tejaratchi

Dolphins use sound to detect the size, shape, and speed of objects hundreds of yards away. Fascinating and complex, the dolphin’s natural sonar, called echolocation, is so precise it can determine the difference between a golf ball and a ping-pong ball based solely on density. Although humans have researched these intelligent marine mammals for decades, much of their acoustical world remains a mystery.

One of the keys to dolphin echolocation is water’s superb conduction of sound. Sound waves travel 4.5 times faster in water than they do in the air. Dolphins use this to their advantage, in ways that would make a superhero envious. Using nasal sacs in their heads, dolphins send out rapid clicks that pass through their bulbous forehead, or “melon.” The sound is focused, then beamed out in front of the dolphin. The sound wave speeds through the water, bounces off the object under investigation, and is reflected back to the dolphin. Fat-filled cavities in the dolphin’s lower jaw receive this information and auditory nerves conduct it to the middle ear and brain, where an acoustic picture is created.

Scientists say that dolphins may also use clicking to communicate with one another. Although dolphins do not possess vocal cords, they still “speak” using sounds such as whistles, squeaks, and trills. A mother dolphin may whistle to her newborn for days, apparently to imprint a signature whistle upon her baby that will enable it to recognize her. It is believed that dolphins use whistles to identify one another and possibly for other functions, such as communicating strategic alerts while hunting in a group, but scientists have yet to crack the code. Many doubt, however, that dolphins have a formal language akin to that of humans.

In the 1950s, researcher John C. Lilly helped pioneer the systematic study of dolphin vocalization. A strong advocate of interspecies communication, Lilly wrote several books about dolphins, inspired the film Day of the Dolphin (1973), and was a supporter of the Marine Mammal Protection Act of 1972. Another pioneer of dolphin research, Kenneth S. Norris, first obtained evidence of dolphin echolocation by blindfolding a bottlenose to test its ability to locate an object underwater.

Since the 1960s, American military scientists have studied dolphins, and have trained them to perform such tasks as attaching explosives and eavesdropping devices to enemy ships or submarines. In the mid-1980s, the U.S. Navy began training dolphins to search for mines using their echolocation. In 2003, dolphins were deployed for the first time in a real war situation to probe the seafloor for mines near the Iraqi port of Umm Qasr. For decades, animal activists have opposed the use of dolphins for entertainment or military activities, citing questionable training methods and the stress-related illnesses, such as ulcers, that the animals can manifest in such situations.

Dolphin advocates also object to the navy’s use of manmade sonar, which is used to scan and investigate the ocean depths, claiming that it is harming dolphins and other marine mammals. They point to incidents such as the beaching of four different whale species off the coast of the Bahamas in March 2000, following navy sonar exercises in the area. Marine mammals strand themselves for a variety of reasons, but investigations confirmed that navy sonar caused the Bahamas stranding. Researchers are not exactly sure how manmade sonar affects marine mammals. Some believe the intense sounds may scare or disorient them and cause them to rapidly flee to the water’s surface, resulting in a sort of decompression sickness that damages sensory organs and causes internal bleeding.

If technological sonar can be implicated in the death of dolphins, it would be a tragic irony, considering that the sonar is based in part upon nature and dolphins’ superior echolocation capability. Efforts to replicate dolphin echolocation continue to fall short, as humans have yet to achieve the complexity and precision that 50 million years of evolution has bestowed upon dolphins. Perhaps if scientists could understand dolphin-speak they’d have more luck, but for now the true nature of dolphin communication remains mysterious.

Early explorers hacking their way across Florida’s bushy landscape sometimes returned with amazing stories of mermaids basking in sparkling waters — or hideous monsters patrolling the seas. As NATURE’s Springs Eternal reveals, however, these tall tales were inspired by one of the most remarkable inhabitants of Florida’s springs: the manatee, or sea cow.

Manatees are marine mammals, like dolphins and whales. But they don’t share a dolphin’s sleek shape. Instead, they are slow, bloated animals that look like a pig or hippopotamus set to sea. And like livestock, they graze on vegetation, such as sea grasses.

Around the world, there are four kinds of manatees, which are also known as dugongs or sirenians (after the “sirens,” or mermaids, of ancient lore). A fifth species, the Stellar’s sea cow, used to live off the coast of Alaska, but hunters drove it to extinction in 1768, less than 20 years after it was first described by shipwrecked Russian explorers.

The Stellar’s sea cow was easy to kill because it lived in shallow waters, and was slow and fearless — just like its modern-day Florida cousin. Indeed, people can often paddle right up to a manatee, especially when the creatures gather by the hundreds each winter in a few Florida springs, such as the Crystal River, featured on Springs Eternal. The manatees are drawn in from their ocean territories by the springs’ warm waters and bountiful crops of vegetation.

Unfortunately, the manatees, which like to swim just below the water’s surface, are vulnerable to fast-moving boaters, who often run over the animals without realizing what has happened. And the gentle creatures are also threatened by water pollution, which is causing Florida’s once transparent spring waters to become increasingly cloudy. Much of the pollution is in the form of excess nutrients, such as nitrogen fertilizer from lawns and farms, which can trigger unwanted blooms of algae and tiny toxic organisms. These blooms sometimes form a deadly event known as a “red tide.” In the winter of 1995, for instance, nearly 400 Florida manatees (about 20 percent of the population) died from exposure to red tide.

Luckily, people are taking steps to protect manatees. Florida is attempting to educate boaters to slow down in areas inhabited by manatees. And the federal government has established several manatee refuges, where the animals can winter without worry of disturbance. The refuges have also proved a boon to researchers. They have learned, for instance, that though manatees may look ungainly, they can sprint short distances at speeds of up to 15 miles per hour, though they usually paddle along at about 4 miles per hour. Scientists have also shown that manatees have well-developed eyes: in clear water, they can detect objects more than 50 feet away. And they have been able to collect data that suggests that manatees can live 60 or more years.

It’s too early to know if such information will help prevent the Florida manatee from following its Alaskan cousin into oblivion. For the moment, however, visitors to Florida’s remarkable springs can still see the gentle animals that gave rise to myths of monsters and mermaids.