I'm horrified by this! They even
lease out dolphins to 'certified environments' (whatever they mean by that). Transportation is extremely stressful to dolphins. Also, dolphins in captivity and in constant close contact to humans are susceptible to a range of human diseases (constant problems with Staphylo-/Streptococcus infections).
I'd never heard of the place, so I googled a bit. Sure enough, a 'Boycott Melka' link came up, which took me to an (ehrm) erotic website
There are many responsible dolphin watch operators. There are even some places (like the aforementioned Monkey Mia) where wild dolphins come close to shore. Swimming with them should never be enforced, nor should they ever be chased, as is the case with wild dolphin watching in Lovina.