In November 1963, he married Patricia Anne Johnston in Vancouver, British Columbia, moving shortly thereafter to Australia, where he joined the Commonwealth Scientific and Industrial Research Organisation in the Division of Wildlife and Ecology, now the Division of Sustainable Ecosystems.
Together with Michael Crowley, Chris Davey, Peter Fullagar, Ederic Slater, Petrus Heyligers and others, Van Tets helped to establish and maintain a long term ecological study on Montague Island, NSW.
On retirement in 1988, Van Tets continued to work as a research fellow and as curator of osteology for the Australian National Wildlife Collection and the Faunal Reference Collection of the Prehistory Department of the Australian National University.
The extinct New Zealand stiff-tailed duck, Oxyura vantetsi, was named in his honour.
[3] The Gerard Frederick van Tets Field Research Station on Montague Island, NSW was named in recognition of Jerry's work there.