
CHENNAI: The mystery behind mass mortality of Olive Ridley turtles is getting murkier with neighbouring Andhra Pradesh reporting 3,000 deaths, while the toll in Chennai continues to skyrocket despite stringent measures. Even in the case of Andhra Pradesh, the primary cause is death by drowning, pointing the needle of suspicion towards destructive fishing practices like bottom trawling.
Speaking to TNIE, AP chief wildlife warden Ajaya Kumar Naik said, “Yes, turtles are dying here, but I don’t have the exact death count. We are working closely with the fisheries department to prevail upon the trawl boat fishermen to use the Turtle Excluder Devices (TEDs).”
However, Tree Foundation founder Supraja Dharani confirmed that the number of deaths in AP this nesting season has crossed 3,000 and there is a pattern to it. “We are getting a large number of turtle carcasses south of fishing harbours. The ocean currents are moving from north to south, similar to what is observed in Chennai. The turtles killed by trawl fishing nets between Pulicat and south AP coast are all getting washed ashore on Chennai beaches,” Supraja told TNIE.
On Wednesday, Chennai witnessed the ‘deadliest massacre’ yet with over 130 partially decomposed Oliver Ridley carcasses beaching. On Marina alone, 27 carcasses were found, according to Students Sea Turtle Conservation Network (SSTCN).
Turtle expert K Sivakumar, a member of the Marine Protected Areas Commission in IUCN and radio-tagged about 60 Olive Ridleys in Odisha and Sri Lanka, told TNIE that the numbers were “shocking” and needed a deeper analysis to understand the causes. “I suspect intensive trawling has been done unknowingly in congregation areas, where females and males come together for mating around this time.
This might have resulted in mass mortality. If drowning is the cause, there is no doubt turtles are getting entangled in fishing nets and dying. Both Andhra Pradesh and Tamil Nadu governments must enforce the use of TEDs. The nearshore waters of Tamil Nadu and Andhra Pradesh are a very important migratory route for the Odisha group of turtles that travel in lakhs of numbers for the arribada in Gahirmatha.
Our radio-tag data shows at least a sizable nesting mothers migrate very close to the shore,” Sivakumar said. Further, he suggested a DNA analysis and genetic matching of dead turtles in Chennai with the turtles in Odisha, which will reveal whether these are migratory or resident populations. “If these belong to the resident population then we are staring at a bigger disaster.”
Naturalist Yuvan Aves observed there are a good number of male turtles also washing ashore dead. “I saw a lot of males as well during the beach walks.” When contacted, R Suresh Kumar, a turtle expert from the Wildlife Institute of India, said if males are also dying then the congregation areas would be disturbed. “Our studies in Odisha show turtles congregate in large numbers close to the shore. There are techniques to identify these areas and protect them,” he said.