Thanks littleRedPanda.
I think the World needs to conserve as many species as possible and that Zoos could help by looking at their collections.
Do they really need to keep so many 'Least Concern' species? Some zoos have more than one exhibit showing the same species, which have no conservation value and are shown at hundreds of zoos.
Endangered species should be into 2 categories
1 Species that can be bred in captivity and released in the wild. Prioritise these species as they are a good example of conservation and can be used to counteract the "What is the point of zoos" protesters. They do not need larger enclosures to house ever increasing numbers of progeny and zoos would not need to send the progeny to other zoos, which may have spent money creating new enclosures, replacing the space allocated to less popular endangered species, which could be part of a reintroduction scheme.
2 Species that cannot be released into the wild. There should be more effort in conserving them in the wild. This can also help other species and their natural habitats. If captive big cats aren't going to be released into the wild, it doesn't matter, on a conservation basis, if they are colour morphs. As many visitors seem to prefer the colour morphs, the zoos could increase revenue and some of this could be used to conserve the species in the wild.