In 1926 Mowbray returned to Bermuda and built the Bermuda Aquarium. Dr. Charles Townsend, an American zoologist, organized several overseas trips for Mowbray to collect new fish specimens. The trips were paid for by Vincent Astor. He and Astor traveled to the Galapagos Islands in 1933. They brought back tortoises and penguins, expanding the aquarium to a zoo. Mowbray then became the first person to successfully breed both the Galapagos tortoises and penguins in captivity.