Unoccupied aircraft system surveys target leatherback (Dermochelys coriacea) conservation in the Rio de la Plata estuary, Argentina

TERYDA N.; PROSDOCIMI L.,; VELEZ RUBIO G.; CARTHY R

Simposio; 40th Annual Symposium on Sea Turtle Biology and Conservation; 2024

Research and conservation efforts for sea turtles have long benefited from technological advances that expand our understanding of their population trends and threats. Better information on habitat use, population densities, and demographic distribution, as well as interaction with anthropogenic threats is essential for the conservation of these species; therefore, a need exists for better and more efficient ways to study them in areas like the Rio de la Plata Estuary (RLPE) in Southwestern Atlantic Ocean (SWAO). This area is an annual migratory foraging destination for adults and large juveniles leatherback turtles (Dermochelys coriacea). Several studies on sea turtles in SWAO have given an essential, yet partial description of habitat use and population abundance, highlighting the importance of the RLPE as a key foraging ground for sea turtles in the SWAO, and the importance of considering the region as focus for conservation efforts. Furthermore, this area is a highly important conjoint fishing ground for Argentina and Uruguay, representing a high susceptibility risk for bycatch.During the last decade Unoccupied Aircraft Systems (UAS, also known as drones) have been identified as useful tools in wildlife ecology, showing to be highly valuable, especially to reach restricted or difficult-access habitats and to study endangered species. In addition, the use of UAS allows the scientific community to reduce their cost of research and carbon footprint. Although UAS use is starting to become more common in sea turtle research and shows promising advantages for population studies, this technology has not been fully applied in different sea turtle habitats such as in RLPE.This study represented the first to evaluate the applicability of UAS technology for sea turtle monitoring in the region of RLPE and for developing pilot standardized protocols for UAS future implementation worldwide. At the same time, our aim was to test different strategies for using this tool by evaluating the presence of leatherback turtles in RLPE. We conducted surveys over the water with a UAS in the Santa Teresita (Argentina), in March 2020 evaluating environmental variables and different flight patterns. We tested three surveys transect techniques for detecting individuals over the water from the coast and from a boat.The survey testing allowed us to standardize a methodology for UAS surveys in the area and to show the potential use of this technology in poor water clarity is feasible for sea turtle monitoring. We identified 72 leatherback turtles and 10 Franciscana dolphins (Pontoporia blainvillei) in the study area using a zigzag flight pattern around a boat. Consequently, this study has the potential for not only revolutionizing traditional surveying methods by applying the newest technologies in sub-optimal conditions in SWAO, but also for providing comprehensive, highly valuable, and needed information on habitat use, distribution and abundance of the leatherback turtle in one of the main feeding grounds in SWAO, providing explanatory power for managers to design regional plans for fisheries management and to establish effective conservation efforts in the area.