A.V.C. College (Autonomous), Mannampandal, Mayiladuthurai. Thiruchirappalli, Tamil Nadu, India

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The dynamic ecosystem of sandy beaches is shaped by processes such as erosion, accretion, and sediment deposition. In many coastal regions around the world, these beaches also serve as nesting habitats for sea turtles and have a significant influence on their reproductive success and hatchling recruitment (Wood & Bjorndal, 2000). Beach characteristics such as slope, width and vegetation cover are known to influence sea turtle nest site selection (Jankie & Lawrence, 2013; Bladow, 2017). Olive ridley sea turtles nest en masse, in a phenomenon called an arribada, at a few known sites on the east coast of India and Mexico and Central America. These mass nesting beaches are often located near river-mouths and are highly dynamic in nature. To understand the characteristics of these nesting habitats, this study examined the variation in beach characteristics at the Rushikulya mass nesting beach in Odisha. Spatial and temporal variation in beach profiling data (Figure 1, 2), collected between 2012-2022, across different sections of the mass nesting beach were determined and the influence of distance from the river-mouth on these beach parameters and their relationship with solitary and mass nesting intensity was examined.

Figure 1. People conducting beach profile surveys. (Photo credit: Chandana Pusapati)

Figure 2. Beach erosion and exposed eggs. (Photo credit: Bipro Behra)

Results showed that beach slope and beach width varied significantly between nesting seasons across all sections of the nesting beach. The beach width decreased with increasing distance from the river mouth, while beach slope showed marginal variation. Beach width influenced the nesting intensity across various sections of the beach. However, nesting intensity did not vary significantly with distance from the river-mouth. These findings indicated that changes in the habitat characteristics could significantly influence the number of turtles able to nest successfully and/or the hatching success (proportion of eggs that produce a hatchling) in a nesting season. The olive ridley turtle’s preference for nesting beaches near river mouths might indeed confer an advantage given that the beaches are wider near the river-mouth. This study underscored the importance of long-term monitoring of spatial and temporal dynamics in nesting beach characteristics. With increasing frequency of unseasonal rain as well as coastal developmental projects, beach characteristics might change significantly. Future studies should, therefore, prioritise investigating the evolving dynamics of the nesting beaches, facilitating the development of strategies to mitigate adverse impacts and ensuring effective habitat management.

Literature cited:

Bladow, R.A., S. Miton, J. Wyneken, J. Baldwin & T.R. Briggs. 2017. Beach dynamics, beachfront development, and climate change: Interactions that impact sea turtle nesting beaches. M.Sc. Thesis. Florida Atlantic University, Boca Raton, USA.

Jankie, S. & A. Lawrence. 2013. A comparison of beach morphology and physical characteristics of Turtle Beach, Tobago and Grande Riviere, Trinidad and its implications for turtle nesting. Journal of Chemical Information and Modeling 53: 1689-1699.

Wood, D.W. & K.A. Bjorndal. 2000. Relation of temperature, moisture, salinity, and slope to nest site selection in loggerhead sea turtles. Copeia 2000: 119-128.