The Oakland Zoo will release 44 western or Pacific pond turtles today as part of a “Headstart” program for the imperiled aquatic chelonians, which once ranged from Baja, California to Washington state.
As part of a 5 year collaborative surrogate rearing program, zoo keepers at the San Francisco and Oakland zoos have worked with herpetologists at Sonoma State University to help augment wild populations of this vanishing species of freshwater turtle. Although they may be locally common in some parts of their current range, the species is recognized as vulnerable by the International Union for the Conservation of Nature.
Head Start projects for chelonian conservation programs increase the chance of survival of these aquatic reptilians through surrogate rearing programs, because in the case of ectotherms, captivity encourages faster growth and ultimately larger sizes of juvenile turtles selected for release into the wild. The larger carapace of the captive reared juvenile turtles discourages predation on the animals. Wild born and reared conspecifics are smaller and more vulnerable to predation.
Typically, the eggs of wild turtles were collected and brought back to these regional West Coast zoos to be incubated, but this year the turtle eggs were incubated in the field, which allowed biologists to collect data on natural environmental conditions, influencing the gender of the offspring. The hatchlings were then brought to the Zoo where they were reared by foster parents—zoo keepers —trained in herpetoculture and the husbandry of herpetofauna.
Together the institutions have been studying the reproductive biology of the Pacific pond turtle, threats to the species and other aspects of their conservation and biology post-release, like foraging ecology.
The major threats to the Pacific pond turtle are habitat loss and degradation, disease, and competition with the invasive red-eared slider, another species of Emydid turtle.
The Western Pond Turtle Recovery Project began at Seattle’s Woodland Park Zoo.
For more information, visit this link.