Amur Softshell Turtle (Pelodiscus maackii) Population Size, Structure, and Spatial Distribution.

Simple Summary: In this study, we investigated the population size of Amur softshell turtles (Pelodiscus maackii) around Jewellery Island, a river island in the mid-stream of the Ussuri River using continuous-time capture–recapture methods, and analyzed the spatial distribution of Amur softshell turtles based on cage trapping results. The results revealed the disturbingly low population density of Amur softshell turtle in this area, highlighting the urgent need for targeted conservation efforts. Our spatial distribution study indicates that juvenile turtles predominantly inhabit still-water channels and vegetated shoreline areas, emphasizing the critical importance of these habitats. This study establishes a foundational framework for future population assessments and pinpoints vital conservation areas. Our results fill a gap in the knowledge of the natural history of this endangered species. Freshwater turtle species preservation relies on understanding their population dynamics and geographical distribution. Amur softshell turtles (ASTs [Pelodiscus maackii]) are poorly protected due to insufficient awareness and the population in Northeastern China has experienced a steep decline compared to previous years. This study aims to investigate the population density and structure of ASTs in the Jewellery Island area of the Ussuri River in Northeast China using continuous-time capture–recapture methods in closed populations. A three-month mark–recapture study was conducted in 2022, resulting in 35 juvenile captures, including 12 recaptures from 23 marked individuals. The estimated population size in the study area was 40.79 ± 9.75 (95% confidence interval, 95% CI = 27–65), translating to 0.663 ± 0.158 turtles/ha (95% CI = 0.44–1.06 individuals/ha). Approximately 35.4–85.2% of the estimated population was marked. Additionally, we explored the influence of environmental variables on turtle distribution by dividing the surveyed sites into seven sections based on their natural characteristics. The ASTs distribution inferred from trapping successes was considerably different among sections, with most turtles (91%) captured at the vegetated shoreline and in water channel 2. This research offers essential baseline data to support future assessments of ASTs population on a larger scale and to inform the development of conservation strategies. [ABSTRACT FROM AUTHOR]