Whether dolphins (particularly bottle-nose) should be kept in captivity is a separate argument and often under a lot of debate. However I am interested by the enclosures in which they are kept, they always seem to be the stereotypical "sea park" blue wash enclosures with little/no substrate. (excluding the occasional sea pen in some Caribbean sea parks) I always wondered, especially if they are not being used as performers, why are they not kept in enclosures with a more "natural" and larger surrounding. For example instead of a blue wash, glass and concrete enclosure why not a deep, well lit indoor enclosure such as the one at Georgia aquarium that houses the whale sharks? A small pod of dolphins in that tank would look stunning and might even have the same impact as all the current large fish like the potato bass and manta-rays. I know its a big appeal to see dolphins preform but after all.. their dolphins! I would much rather see them interact with their environment, each-other and the occasional visitor passing the glass. Maybe that's just me, but would defiantly like to know why they are not kept like this (besides training and possible health checking purposes)
The Dolphin Research Center keeps their dolphins in naturalistic enclosures, they are even right up against the ocean and even get visits from wild dolphins on occasion. Dolphin Research Center - Dolphin Research Center The Mirage Dolphin Habitat uses a sand substrate and filtration system.
The Dolphin Quest Oahu and Hawaii facilities keep their dolphins in man made salt water lagoons with sand bottoms, rocks, seaweed, and fish. They are truly impressive facilities. Numerous European facilities (Duisburg, Nurnberg, Acquario di Genova, Harderwijk, and a few others come to mind) also house their dolphins in lovely natural tanks with mixtures of rocks, kelp, sand and other animals (fish, invertebrates, Sea Lions, etc...), although some facilities do this to more extents than others.
Some parks use chemically treated water that kelp and such couldn't survive in. But not all places have chemically treated water, so I'm not entirely sure. Places that do dolphin shows and the like usually have the show area make up a large portion of the exhibit, and I guess a lot of kelp and rock formations would make it more difficult for them to do tricks. I too would like to see dolphin tanks with more "natural" environments, partially for enrichment and partially cause, yeah, it would look cool. A blank tank is just boring to look at. Since dolphin shows seem to be very, very slowly going out of style, I'm wondering if we'll start seeing more naturalistic dolphin tanks.
Not a display facility but the Hawaii Institute of Marine Biology keeps their two Bottlenose Dolphins and one False Killer Whale in a facility moored right off Coconut Island. Animals Also, Dolphins Plus keeps their Dolphins in a lagoon and also in a canal right next to the ocean. Dolphins Plus- Family owned swim with dolphins Facility.
Roatan Institute of Marine Sciences has dolphins in some kind of sea pen type of thing. Looks pretty nice. I don't think they do display, but they offer swim-with-dolphin programs, train dolphins, learn about dolphins, that kind of stuff.
SeaWorld's dolphin tank (San Diego) was kinda small, but it stretched out far, but I knew it was small.
Shamu Stadium uses an ozone filter. It remains to be seen how the new extension is going to look, my bet is that the rising floors (if it has them) will make it hard to grow kelp or anything, but who knows. I don't know what the Killer Whale's taste in decor is either, so I can't comment on that.