Poster Presentation/Lightening Talk Australian Freshwater Sciences Society Conference 2022

Turtle tracking - using baited remote underwater videos to monitor freshwater turtles (#155)

Daniel Coleman 1 , Rebecca Wood 1 , Caitlan Deeth 1 , Tim Haeusler 1
  1. NSW Government - DPE Water, Wollongong, NSW, Australia

Freshwater turtles play an important role in aquatic ecosystems. They are long-lived, charismatic animals that contribute to improved water quality and nutrient cycling by scavenging. Traditional survey methods (e.g. traps) for freshwater turtles require long sampling times and may cause some degree of distress to target and non-target animals. New and innovative survey techniques utilising underwater cameras have the potential to track changes in turtle populations whilst being more cost effective and less invasive than traditional trapping surveys. We trialled the use of Baited Remote Underwater Videos (BRUVs) at 5 sites in the Northern Tablelands of NSW, Australia. Our aim was to test if BRUVs could be used for relative abundance, size and sex estimates of freshwater turtles. We also compared BRUVs to cathedral traps and identified key considerations for future use of this survey method. Our study successfully detected and identified all 3 species known to occur in the study area. Relative abundance measures obtained using BRUVs were statistically similar to cathedral trapping techniques. A total of 83 turtle images were captured, 13 (16%) and 26 (31%) images were able to be measured and sexed respectively. BRUVs did not capture any hatchling or small turtles on camera, which suggests that juveniles were either absent, rare, or not sampled well with this method. Our study shows that BRUVs are a useful survey method for relative abundance measures, but require further validation and consideration of the influence of turbidity, time of day and video duration on the results obtained using this method.