The global reach of zoos and aquariums in visitor numbers and conservation expenditures.

A survey conducted by the World Association of Zoos and Aquariums, in collaboration with national and regional zoo and aquarium associations, showed that annually more than 700 million people visit zoos and aquariums worldwide and are thus potentially exposed to environmental education. Furthermore, the world zoo and aquarium community reportedly spends about US$ 350 million on wildlife conservation each year. Therefore, the world zoo and aquarium community has the potential to play an important role in both environmental education and wildlife conservation. Systematic reviews are encouraged to provide further evidence for the effectiveness of zoos and aquariums as centers of education and conservation.