Nesting Activity of the Chinese Softshell Turtle, Pelodiscus sinensis, on the Yellow River, Northwestern China

Nocturnal emergence facilitated by thermally‐induced hatching in the Chinese softshell turtle, Pelodiscus sinensis

“…We collected 12 adult female P. sinensis (700–1500 g) from the Yellow River in northwestern China (34.95°N, 110.25°E) in May 2021, and kept them in a preset enclosure to lay their eggs. The enclosure (20 m length, 10 m width, 1.2 m height) was set up in their natural habitat (Zhu et al, 2021 ) and was made of 5 × 5 cm wire mesh (a lattice large enough to allow hatchling dispersal), including a water area of about 10 × 5 m and a land area of 10 × 15 m. We monitored the nest sites through four solar‐powered infrared camera systems (EXF‐HSD, Enxun Electronic Technology, Shenzhen, China) hung on 2.5 m‐high poles around the enclosure.…”

“…The probes were set to record synchronously every 10 min to an accuracy of 0.1°C. We used only one temperature recording station because P. sinensis lay their eggs on flat ground lacking vegetation cover (Zhu et al, 2021 ), so each nest in the enclosure experiences the same sun exposure, and thermal differences between nests are negligible (Qingjun Zhu, unpublished data).…”

“…One week before the estimated hatching day (mean incubation period = 54.8 days, Zhu et al, 2021 ), we excavated the nests again and installed a small infrared camera device (EXF‐P3‐4G, Enxun Electronic Technology) in each nest to monitor the hatching process of the embryos. The nests were refilled with sandy soil after equipment installation, and a thin ceramic tile (15 cm length, 10 cm width) was placed across the center of the nest (above the eggs) to prevent the soil from covering the camera equipment (Figure 1 ).…”

“…In a prior study, we discovered that a shallow‐nesting (vertical nest depth of approximately 10.5 cm) freshwater turtle species, the Chinese softshell turtle ( Pelodiscus sinensis ), exhibits nocturnal emergence in most cases (Zhu et al, 2021 ) and that their hatchlings do not linger in the nest for more than a day (Qingjun Zhu, personal observation). Considering these observations, the present study aimed to determine the following three exploratory goals: (i) whether daily temperature variations in the shallow nests cued hatching in P. sinensis .…”

Eating China's softshell turtle species to extinction

“…Furthermore, farmed individuals are fed growth hormones and antibiotics which affect human health and are thus less preferred. This has prompted an increase in the number of fishermen hunting wild stocks, even within nature reserves (Zhu, Kong & Shi, 2021).…”