Mystic Aquarium & Institute for Exploration

African penguins are commonly displayed in zoos and aquariums throughout North America . Only a few facilities maintain their birds in saltwater exhibits, while the remainder are in freshwater. Supplementation with salt has been a long-standing practice in many facilities, yet there is disagreement amongst facilities as to whether penguins kept in freshwater require salt supplementation in their diets.

A controlled study using both captive and wild penguins was designed and led by researchers at Mystic Aquarium in conjunction with the Seneca Park Zoo, Potawatomi Zoo, New York Aquarium and the South African Foundation for the Conservation of Coastal Birds. The 10-month study was designed to compare sodium and chloride electrolyte concentrations in the blood from birds living in either saltwater or freshwater with salt supplementation, and in freshwater without salt supplementation. Results of the study demonstrated that there were no differences in electrolyte concentrations between the different exhibit water/supplement scenarios and thus concluded that salt supplementation is not necessary to maintain normal sodium and chloride levels. Due to this work penguins at Mystic Aquarium no longer receive salt supplementation as part of their diets. Many other facilities have followed suit and removed salt supplements from the diets of their penguins as well.