Emergency room pediatrician Dr. Lily Gomez dives with a whale shark in one of the viewing tanks at the Georgia Aquarium in downtown Atlanta, 2006. Six hours after her night shift at Children's Health Care of Atlanta at Scottish Rite ended, Gomez is donning scuba gear and getting ready for an hour underwater as a volunteer at the Georgia attraction. Ric Feld/AP
Daniil, 8, plays with dolphins during a dolphin-therapy session at a dolphinarium in Kiev, Ukraine, Oct. 14, 2013. The dolphinarium organizes sessions for pregnant women, children, and people with disabilities who are said to benefit from swimming and playing with the dolphins. Efrem Lukatsky/AP
A Pacific white-sided dolphin approaches visitors wearing diving helmets and gears in an ocean aquarium at Enoshima Aquarium in Fujisawa, southwest of Tokyo, Oct. 28, 2006. By using the gears called 'Seawalker,' non-swimmer visitors also can walk in 3 meters deep of water and enjoy dolphin observation. Itsuo Inouye/AP
Snorkelers swim in the Georgia Aquarium's Ocean Voyager tank, 2008, in Atlanta. John Bazemore/AP
A woman pets an endangered Manatee while swimming in the Crystal River in Homosassa, Florida, 2005. Adult manatees have been known to exceed lengths of 13 feet and weigh over 3,500 pounds and Scientists believe that manatees are capable of living for 60 years or more. Marc Serota/Reuters
Snorkelers swim with a whale shark, the world's largest fish, at Maldives' South Ari Atoll, 2012. The whale shark inhabits in tropical and temperate waters and is listed by the International Union for Conservation of Nature as a vulnerable species. David Loh/Reuters
Tourists cuddle and swim with dolphins at the dolphin center, located in a natural lagoon in Varadero, Cuba, 1998. John Moore/AP
Yang Yang, 3, plays with a Beluga Whale at Qingdao Polar Ocean World, east China's Shandong province, 2007. Yang is a fan of ocean creatures and had always hoped to swim alongside the Beluga Whale at Ocean World. China Daily/Reuters
The US Postage Service, along with Sea World Animal Care specialist Wayne Grinder, unveils the manatee stamp at Sea World of Florida in Orlando, 1996. The stamp is the result of a three-year letter writing campaign waged by 22 Knoxville, Tenn., youths to focus attention on the plight of this endangered species. Chris Gotshall/AP
Volunteer diver Dr. Lily Gomez swims with a small pill camera veterinarians hope could help diagnose gastrointestinal diseases in marine animals, as a whale shark glides past her at the Georgia Aquarium in Atlanta, 2009. Gomez was testing if a receiver could pick up a signal from the camera in the 6.3 million gallon Ocean Voyager tank. John Bazemore/AP
Diver Brad Norman photographs a whale shark at Ningaloo Marine Park, off the coast of Western Australia, 2007. The 1000th whale shark, a rare and threatened species was discovered by researchers using a global program in which eco-tourists and scientists identify new sharks and lodge photographs on an online library. Rolex/Kurt Amsler/Reuters
A shark swims above a diver during a feeding demonstration at the Two Oceans Aquarium in Cape Town, South Africa, 2006. Experts agreed that people posed a far greater risk to sharks than the other way around. Denis Farrell/AP
A trainer swims with Keiko, a 5-ton killer whale best known for his appearance in Warner Brothers' 'Free Willy' films, after he was lowered into his pen in Icelandic waters, 1998, for the first time after his capture 19 years before. Reuters
A SeaWorld orca killed a trainer during a performance in 2010. The appeals court is being asked to decide if restrictions imposed by OSHA on orca-human contact are a sensible safety measure or unfair curtailment of SeaWorld's main attraction.
Marine mammal park company SeaWorld, whose trainers were barred from close contact with killer whales after an orca named Tilikum killed a trainer in 2010, is arguing in federal appeals court that government regulators overstepped their authority when they restricted that contact.