SATURDAY, JULY 27, 2024
Siddhali Nhanu Mahale (ecobaaai)
One summer evening, a group of friends rushed to visit Morjim beach. The excitement was of something they were about to see for the first time in their lives. The Forest Department, the guardians of the sea turtle nesting site, were going to release the Olive Ridley Sea Turtle hatchlings that night to the sea. The friends were delighted to witness the process of baby turtles crawling towards their home - the sea.
Olive Ridley Sea Turtles (Lepidochelys olivaceae) are the original tourists of Goa much before humans became one. Sea turtles are amazing creatures, they spend their entire lives in the sea swimming thousands of kilometres but they are born from eggs laid by their mother on land (sand). According to scientific theories, it’s the ability of sea turtles to detect the earth’s magnetic fields that help them navigate back to their motherland. But exactly how they do it, is still a mystery.
Goan beaches are the birthplace of Olive Ridley Sea Turtles, these include Agonda, Galgibag, Morjim and Mandrem beaches. Earlier, the popular Calangute and Baga beaches were also included but over the years human tourists have outnumbered the sea turtles.
The male Olive Ridley Sea Turtles never come back to land. However, the female Olive Ridley Sea Turtles always return to the very same beach they were born to lay up to 120-150 eggs each time. The nesting season lasts October-April. Mother turtle digs a nest in the sand, lays the eggs, buries them and leaves. The temperature at which the eggs are hatched plays an important role in determining the gender of the turtle, higher temperatures (above 30 degree Celsius) results in females and lower temperatures (28 degree Celsius or below) in males.
Full moon nights are preferred by the female turtles to lay eggs as it draws water to the highest high tide which ensures safety of her eggs from inundation during all other tides and also reduces her efforts while movement from water to sand with her pregnant self. The eggs hatch in 45-70 days depending upon the circumstances in which they remain. Nowadays, due to increasing human threats than natural threats, efforts are taken by the Forest department and other responsible individuals to keep the eggs safe and then release them in waters. Ideally after coming out of the egg, the hatchling directly marks its way to the sea depending on the single light source, the moon that brightens up the water surface guiding the baby turtles to sea.
Today, sea turtles face several threats to their existence. The primary threat to the sea turtle at the beach is light and sound. Lights from shacks, mobile flash lights, fireworks or any other form of light disrupts the sea turtle nesting activity. The mother sea turtle gets disturbed from unnecessary light, this may result in her abandoning that particular nesting site. Also light sources other than moonlight disorient and mislead baby hatchlings way back to the sea. Noise too creates many vibrations on land and sea which causes disturbance to the sea turtle nesting cycle.
Threats like sand mining, irresponsible tourism, improper disposal of waste especially single-use plastic creates a major havoc to the lives of sea turtles. Activities like use of laser lights on the beach, beach driving, loud music etc are also a huge problem. Ecologically sound decisions are needed to ensure continuation of Olive Ridley sea turtles visiting Goa. The turtles have successfully survived for at least a hundred million years outliving dinosaurs but evolution has not prepared them from human made climate change, changing environment and pollution. The Olive Ridley Sea Turtles of Goa need space and safety with more stringent rules, for them to continue breeding, so that the future generations of Goa get to observe and study this marvellous marine species forever.
(Siddhali Nhanu Mahale (ecobaaai) is an amateur environmentalist and part-time researcher striving to find ways to create awareness about the environment)
Beach reality for the nesting season in South Goa
The Olive Ridley Sea Turtle rarely weighs over 50 kilograms. Hatchlings usually weigh between 12 and 23.3 grams. In South Goa Hatchery for the year 2023-2024, a total of 43 pits were observed in Galgibag from which a total of 4192 eggs were laid and 3351 eggs were hatched. Similarly, in Agonda, a total of 181 pits were observed with 17,406 eggs from which 9473 eggs were hatched. The incubation period is usually between 45 and 51 days under natural conditions, but may extend to 70 days in poor weather conditions. Eggs incubated at temperatures of 31 to 32 °C produce only females; eggs incubated at 28°C or less produce solely males; and incubation temperatures of 29 to 30°C produce a mixed-sex clutch. Hatching success can vary by beach and year, due to changing environmental conditions and rates of nest predation.
Rajesh Naik, Deputy Range Forest Officer (RFO)
