Decoding the nesting fidelity of Olive ridley sea turtles along Odisha coast: A multi-dimensional approach

The Odisha coast is one of the world's largest mass nesting (arribada) sites for Olive ridley sea turtles ( Lepidochelys olivacea ), accommodating approximately 50% of the global population. Despite its extensive and ecologically diverse coastlines, Odisha remains the preferred nesting habitat, although its prime reason is poorly understood. This study focuses interdisciplinary approach that integrates environmental and anthropogenic factors to assess the fidelity of Olive ridley sea turtles to the Odisha coast. Socio-environmental data collected from various sources are assessed for fidelity and results indicate that conducive coastal water quality, stable/accreting shorelines, and predominance of coarse/medium sand play a significant role in facilitating mass nesting along the Odisha coast. Further, ocean waves characterized by low steepness, along with less coastal structures and anthropogenic activities, enhance nesting fidelity. The correlation analysis shows that the nesting population is positively correlated with higher genesis potential for tropical cyclone occurrence and negatively correlated with the percentage of beach littering. The cluster analysis reveals minimum coastal structure & erosion, low marine fishing harvest potential and litter activities associated with the maximum occurrence of tropical cyclone could be the plausible reason for mass nesting events. In addition, minimal anthropogenic disturbances, such as fishing activities and tourist flows in Odisha, contribute to minimal risks of bycatch and mortality of sea turtles. In contrast, other coastal states experiences increased habitat loss, pollution, and human interference, leading to a decline in nesting phenomena. The study suggests that Odisha's distinct blend of socio-environmental factors makes its beach vital for nesting habitat. • Nesting fidelity of Olive Ridley to Odisha is studied in relation to socio-environmental factors. • Coastal water quality, beach stability, coastal structures, sediment characteristics and extreme weather events governs the arribada. • Increase beach litter, marine fish production, and coastal structure negatively impacts sea turtle fidelity. • Statistics shows fidelity links to thecoast with increased exposure to extreme events, low coastal development, tourism, litter, and fish production. • Regulated fisheries, coastal infrastructure, shoreline and water-quality monitoring are critical to sustain arribada resilience.