Spatio-temporal variability among loggerhead turtle, <i>Caretta caretta</i>, strandings off southern Brazil

Abstract Since 2015, Brazilian legislation governing resource extraction in the Santos Basin has required daily monitoring of beaches (∼1490 km) in Rio de Janeiro (RJ), São Paulo (SP), Paraná (PR), and Santa Catarina (SC) for fauna strandings. All stranded specimens are necropsied or rehabilitated. Here, we investigate spatio-temporal variability among 5169 loggerhead turtles, Caretta caretta, stranded between 2015 and 2022, and discuss regional management implications. Weekly stranding rates among states ranged between 0.03 (RJ) and 0.54 (PR) C. caretta 100 km–1 and peaked during winter and spring—coinciding with concentrated regional penaeid-trawl effort. Almost all (99%) stranded C. caretta were dead and had advanced decomposition. Overall, there were biases towards female C. caretta (2:1), that increased during summer, and juveniles (2.2:1) across all states, especially in Paraná—encompassing an ecologically important and World Heritage-listed estuarine complex. Identified anthropogenic impacts among stranded C. caretta were low overall (14%) but biased towards fishing (8%) and greatest during winter and spring. Few (∼4%) C. caretta had ingested plastic or were entangled in marine debris. The data support prioritising the jurisdictional management of impacts across SP, PR, and SC during winter and spring, and in the presence of intensified regional trawling effort.