Shifting of river mouth has eroded the long sandy nesting beach
Shifting of river mouth and erosion have changed the terrain of the nesting beach of Olive Ridley turtles near the Rushikulya rookery in Ganjam district of Odisha.
Forest officials and environmental activists are keeping their fingers crossed over its possible impact on nesting of the turtles this year. Its mating season is almost over and nesting is expected to start from the third week of February.
In the recent months, the Ruhsikulya river mouth has shifted towards the north. This has completely eroded the long sandy nesting beach near Kantiagada village, where most of the turtles laid their eggs last year. At present, no sandy beach remains in the area and the sea is touching the casuarina forest on the coastline. This shifting of the river mouth has also led to the formation of a 500-metre-long sandbar of more than 200 metres inside the sea.
Such changes, however, are not new.
Olive Ridleys are known to change their nesting place. In the past, most turtles used to nest near Purunabandha village towards the south, then they shift to the north, to the coastline near Kantiagada.
“It remains to be seen what impact this recent change will have on the nesting site of the Olive Ridleys,” said A.K. Jena, Divisional Forest Officer (DFO) of Berhampur.
The question is whether these endangered turtles would prefer to nest on the recently formed sandbar or not. “Usually Olive Ridleys do not prefer to nest on sand patches that are not connected to the mainland. In 2009, after the shifting of the Rushikulya river mouth, a large sandbar was formed in the area, but Olive Ridleys did not prefer to lay eggs on it,” Mr. Jena said.
Experts say that before mass nesting takes place, a large numbers of turtles waiting in the sea get information on the state of the coast from some Olive Ridleys that come for sporadic nesting. Based on this information, females decide whether to nest or not.
Following the mating season, a large number of female turtles are waiting for nesting. Males have started to return. Even after mating, female Olive Ridleys at times do not lay eggs if the environment is not conducive for nesting.
While some experts say the turtles can keep the fertilised eggs inside their body for two to three years, others are of the view that the females can keep the sperm in their body and opt for fertilisation of eggs whenever they want, said Mr. Jena.
Zoologists say female Olive Ridleys can also absorb fertilised eggs in their body if the nesting situation is not favourable. However, the nesting habit of Olive Ridleys still remains a mystery. In 2007, there was no mass nesting on the Rushikulya rookery coast, while in 2006, there was mass nesting on two occasions.