Insights into Editorial: A turtle recovery plan
Every year, thousands of sea turtles are accidentally captured, injured or killed by mechanised boats, trawl nets and gill nets operated and used by commercial fishermen. They can also sustain internal injuries from fishing hooks or suffer serious external injuries after becoming entangled in nets. Each year, environmentalists record a high number of dead turtles washing up ashore. This heavy toll, of injuries and deaths, occurs when turtles begin migrating to their nesting grounds on beaches and in fishing areas that are their feeding grounds.
Marine turtles along the Indian coast
India has a coastline of more than 8000 km which is rich in biodiversity. Apart from sustaining fishing grounds, India’s coastal waters and beaches provide foraging and nesting sites for a variety of marine species, including sea turtles. Five species of sea turtles are known to inhabit Indian coastal waters and islands.
These are the Olive Ridley, Green, Hawksbill, Loggerhead and the Leatherback turtles. Except the Loggerhead, the remaining four species nest along the Indian coast.
In India, though sea turtles are protected under the Indian Wildlife Protection Act of 1972, under the Schedule I Part II, they face grave threats. Some of the major threats include
- unplanned beach development
- By-catch mortality (in trawl nets and gill nets): By-catch is the name given to ocean animals that are unintentionally caught by fishing gear.
- weak enforcement of fisheries and Protected Area regulations
- To a limited extent, killing of turtles for meat and the poaching of eggs.
The turtle breeding season is usually between November and December. In Tamil Nadu, the Olive Ridley nests between December and April along the Chennai-Kancheepuram coastline. The eastern coastline is the feeding area for Olive Ridley, juvenile Hawksbills and Green turtles. Off-shore waters are also migratory routes for the Olive Ridley while moving towards beaches in Andhra Pradesh and Odisha.
The coastal state of Odisha on the eastern coast of India experiences one of the world’s largest mass nestings or arribada of the Olive Ridley turtle during the months of October to April.
Three of the world’s major mass nesting beaches for this species are located in Odisha, supporting a nesting population of probably more than half a million Olive Ridleys, making this one of the most critical conservation areas for this species globally.
Role of Turtles in marine ecosystem
Sea turtles occupy a unique position within the food web. They consume an assortment of prey, including puffer fish, crustaceans, sponges, tunicates, sea grasses, and algae. The unusual life cycle of the animal plays a vital role in transportation of nutrients from the highly productive marine habitats such as sea-grass beds to energy-poor habitats like sandy beaches. This helps reverse the usual flow of nutrients from land to sea.
- Sea turtles, especially the leatherback, keep jellyfish under control, thereby helping to maintain healthy fish stocks in the oceans.
- The Green turtle feeds on sea grass beds and by cropping the grass provide a nursery for numerous species of fish, shellfish and crustaceans.
- The Hawksbill feeds on sponges in the reef ecosystem and opens up crevices for other marine life to live in.
- Turtles are also transporters of nutrients and energy to coastal areas.
- Unhatched eggs, eggshells and fluids help foster decomposers and create much needed fertilizer in sandy beaches.
As turtle populations in general decline, so does their ability to play a vital role in maintaining the health of the world’s oceans.
Integrated conservation measures are needed to rebuild their populations to healthy levels so that they can carry out the full extent of their key roles in ocean ecosystems.
- Enforcement of Bans:
Under current regulations, mechanised trawl boats are not allowed to operate within 8 km of the shore in Andhra Pradesh, 5.5 km in Tamil Nadu and 5 km in Odisha. However, these limits are not being enforced.
Similarly, nets set for ray fish are banned under the law during the season. However, their use by some categories of fishermen is widespread.
The ban needs to be enforced at all levels of fishing and monitored by the respective Fisheries departments, marine police and the Indian Coast Guard. All areas where fishing boats land need to be monitored.
- Turtle excluder devices
Turtle excluder devices or TEDs, are two-dimensional net inserts with large escape openings for turtles. In India, trawlers meant for shrimp fishing are required by law to be fitted with TEDs. If used correctly, TEDs have been found to reduce turtle captures by 90%.
- Seasonal Closures
There are closed seasons for certain types of fishing vessels. Trawlers and motorised craft with an engine output greater than 25 hp are banned. Areas where sea turtles forage and congregate need to be identified and additional seasonal closures need to be implemented within these areas.
- Vessel monitoring system
If sea turtle conservation is to have meaning, all trawl boats should be fitted with a vessel monitoring system that must be kept on at all times. This will provide a simple system of monitoring by the Coast Guard.
- By-catch reduction programmes
Scientists are now working on programmes such as new fishing nets and gear that reduce the amount of By-catch while fishing. Growing public interest in By-catch reduction programmes is motivated by factors such as an appreciation for endangered species and concern for maintaining marine biodiversity.
These small but meaningful measures will help the sea turtles that are our marine heritage have another chance at survival.