Using Microbes to Help Save Endangered Turtles
Four palm-sized western pond turtles paddle in a habitat behind the scenes at Shedd’s animal hospital while four more swim on exhibit in Islands and Lakes—much as all would in their native Washington state. At Shedd, though, the turtles are helping our Aquarium Microbiome Project team understand a fatal shell infection affecting endangered populations of these turtles. Microbes—the right microbes—might be the newest tool in the increasingly sophisticated work of saving endangered species.
how to help
A conservation success story at first
For more than 25 years, western pond turtles (Actinemys marmorata) have been the focus of a conservation coalition led by the Washington Department of Fish and Wildlife (WDFW), along with Seattle’s Woodland Park Zoo and the Oregon Zoo, which, like Shedd, are accredited members of the Association of Zoos and Aquariums (AZA).
Western pond turtles once ranged from Puget Sound to Baja California. But by the mid-1990s, overhunting, habitat loss and predation by introduced animals had reduced the Washington state population to about 150 animals. Since then, the population has slowly rebounded to more than 1,000 turtles at six sites, in large part through a head-start program in which zoo-reared yearlings are released into the wild.
New threat from unidentified disease
But the success of these efforts has been hampered in recent years by the widespread appearance of a mysterious fungal shell disease among the introduced turtles. It appears as shell lesions that can go through the outer layer of the shell to the underlying bone and body tissues, killing the afflicted animals.
Conservation efforts were bolstered when AZA named the western pond turtle as one of 25 species for its intensive SAFE (Saving Animals From Extinction) and initiated a conservation action plan for the turtles that includes the Unidentified Shell Disease Project, in which Shedd is a partner.
“We can take the information we learn in the aquarium and apply to turtles in the field to make sure that they’re healthy and able to survive for future generations.”Dr. Matt O'Connor, staff veterinarian
Something in the water?
Chrissy Cabay, director of Shedd’s Microbiome Project, and Dr. Matt O’Connor, one of our staff veterinarians (and a turtle aficionado), traveled to Washington to investigate a hypothesis that the fungus got a shell-hold on the zoo-raised turtles because their controlled environment is missing critical beneficial microorganisms that are present in their native waters.
Under the supervision of veterinarians with the Washington wildlife department, Shedd and graduate students from the University of Illinois are analyzing more than 600 environmental and animal-associated samples.
The data they obtain will help inform how head-start habitats might be augmented to incorporate beneficial microbes, boosting the turtles' chances of success. Meanwhile, veterinarians with the University of Illinois Zoological Pathology Program, another partner in the disease detective work, are sequencing DNA to identify the fungus attacking the turtles’ shells.