There is a new petition, started by Ric O'Barry of "The Cove" fame, to ban the capture of dolphins and whales in US waters which would then be put on public display. So, in essence, this means aquariums and sea parks could not use animals captured in US waters. This petition is on the US Government website, and if it can attain 100,000 signatures it will be reviewed and considered by the Obama administration. (You do need to register in order to use the site, but they do not spam you.) I do not know if you have to be a US citizen or resident in order to register and sign.
Today there is a growing backlash to keeping cetaceans in captivity. This is based on the knowledge that they are large, far-travelling animals that need dozens or hundreds of square miles to swim. In addition, animals like orcas live in tight-knit family groups for their entire lives, which can be 50-70 years or longer.
This petition is a small step towards protecting those animals from a lifetime of captivity, which usually ends when the animal dies after a short life. Your signature here will be greatly appreciated.