08/08/2014 07:34 BST | Updated 07/10/2014 06:59 BST

See the World, Just Not SeaWorld

The United States is still a go-to destination for many British families setting off on holiday this August - and with good reason. Unforgettable sights such as the Grand Canyon and Niagara Falls make for lifetime memories. But one destination that kind families should never put on their itinerary is SeaWorld.

Unless you haven't picked up a newspaper or been online in the past year, you've probably seen or heard about the riveting documentary Blackfish, which chronicles the miserable lives and deaths of orcas in SeaWorld's theme parks. Blackfish exposed what really goes on at SeaWorld and why no ethical traveller should ever buy a ticket to this marine abusement park. Thanks to the film and campaigns such as PETA US' SeaWorld of Hurt, the tide is turning for SeaWorld. Attendance at its parks is down, musicians scheduled to perform have jumped ship and the world's largest student travel company, STA Travel, pulled SeaWorld promotions from its website after talks with PETA. Still, too many British tour operators are continuing to line their pockets at the expense of animals held captive in watery prisons.

SeaWorld is a big business with a savvy, well-financed marketing team that attempts to make everyone forget that its involuntary performers are living in cramped tanks and will be there until the day they die. Oceans are vast, deep, complex ecosystems. They aren't shallow, barren, chemically treated and painted blue. Putting orcas and dolphins in artificial tanks is like sentencing an innocent person to life in prison. Orcas and dolphins possess sophisticated learning, problem-solving and communicative skills. They live in large groups and have complex relationships that include long-term bonds and cooperative networks. They swim for many miles every day, exploring and discovering new things, meeting up with old acquaintances and sharing news and information.

At SeaWorld, orcas and dolphins can do nothing but swim in endless circles and perform tricks for a reward of dead fish. Deprived of the ability to play at will, gossip freely, choose their own mates or engage in any of the activities that make their lives worthwhile, they become listless, unpredictable and depressed. Kids may be distressed to learn that every single performing orca in SeaWorld's parks is called "Shamu" - as if the animals were all interchangeable.

And what about the youngsters in SeaWorld's tanks? Orca calves usually stay with their mothers for their entire lives. At SeaWorld, mothers and babies are torn apart so that they can be turned into breeding machines and churn out future performers. They wail in anguish as they are forcibly separated. These mothers can do nothing but despair as their babies are taken from them forever. The sheer desolation and hopelessness that these orcas must feel every minute of their lives just to provide human spectators with a fleeting moment of amusement is unforgiveable.

And then there are those tempting "swim-with-the-dolphins" programmes, which SeaWorld and many vacation destinations offer. In the wild, dolphins navigate by bouncing sonar waves off objects to determine their location. In captivity, even the largest pen or tank is far too small for them. Humans are captivated by dolphins, but "swim-with" programmes turn the very animals we value into slaves.

Many facilities operate almost continuously, giving dolphins little respite from streams of tourists. Their diets may be erratic because many facilities generate additional revenue by selling fish to tourists in order to feed dolphins. Assertive dolphins can grow obese, and less aggressive animals may go hungry.

Succumbing to temptation and buying a ticket may also help to finance the slaughter of wild dolphins. As exposed by another recent award-winning documentary, The Cove, every year, thousands of dolphins are killed in gruesome "drive fisheries" in Japan. Most are slaughtered for meat sold in local supermarkets, but some end up in aquariums and marine parks.

And for all this pain, what do children get from visiting SeaWorld? Souvenirs, a sunburn and the fleeting glee of sitting in the splash zone - along with the terrible lesson that it's OK to destroy families and confine marine mammals, fish and other sea life to tanks, simply for "entertainment."