( CNN ) -- Before I started working on the documentary `` The Cove , '' I assumed like many others that dolphins and orcas enjoyed living at Sea World and other marine parks . They always seemed to be smiling , jumping merrily around their tanks , eager to put on a show for human spectators . However , when I met Ric O'Barry , my perspective changed . O'Barry was the man responsible for capturing Kathy -- the original `` Flipper '' -- from the wild and helping to create the language used to train dolphins to do tricks and flips . When Cathy died in his arms some years later , O'Barry realized the whole process of capturing and training dolphins was wrong . He eventually co-wrote the book `` Behind the Dolphin 's Smile , '' where he explains that the smiles you see on these animals are not true reflections of happiness . In actuality , they hate to be enclosed in their holding tanks and are often not fed until it is time to perform their daily routines . During his time as a trainer , O'Barry learned dolphins had true feelings -- they would get depressed , stressed out , even suicidal . In some parks , the trainers have to give the animals Maalox and Tagamet to treat the ulcers that develop from their stress . The horrific tragedy that occurred last week at SeaWorld in Orlando , Florida , has left me deeply shaken . My heart goes out to Dawn Brancheau and her family . Dawn lost her life doing the job that she loved , yet I -- like O'Barry -- believe that this job should no longer exist . We know now that the whale involved in this accident has a well-documented history of violent behavior . SeaWorld knew of this history yet continued to exploit the animal and endanger the lives of its employees to put money in its pockets . If this is n't a wake-up call , I do n't know what is . At this very moment , a dozen boats in the town of Taiji , Japan , are heading out and rounding up hundreds of dolphins in a secluded cove . The fisherman will close off the cove with nets , and with the help of employees from various dolphinariums , they will try to find the next `` Flipper '' among their catch . The fishermen will snatch these beautiful creatures from their natural habitats , hoist them into nets , load them onto airplanes and drop them into a cement tank in the middle of Turkey , Korea or other nearby Asian countries . In some ways , these animals are the lucky ones . These dolphins escaped the fate of many of their pod mates , who are brutally slaughtered with primitive harpoons -- turning the cove into a scene straight from Melville 's `` Moby Dick . '' The water turns bright red with the blood of the slain . The fishermen then transport the meat -- despite health concerns of mercury content in the dolphins ' systems -- back to shore , where they sell it to local vendors . It 's time for us to step up and make a difference in these animals ' lives . Until we make marine parks obsolete , dolphins and other sea mammals will continue to be senselessly captured and slaughtered . We can no longer fall for the argument that SeaWorld shows `` make us love the dolphins and want to understand and protect them '' -- this could n't be further from the truth . As I see it , we will only truly love and understand these animals when we can watch them running wild and genuinely smiling in their natural habitat . The opinions expressed in this commentary are solely those of Fisher Stevens .
Dolphins seem to be healthy , but captive animals experience stress , " Stevens says . Stevens says captive dolphin trade leads to slaughter of the animals . Until we make marine parks obsolete , the trade will continue , Stevens says .