TREE Foundation, India
The south Indian coast is the migratory route for olive ridley turtles en route to their mass nesting habitats along the beaches of Odisha in north-east India. The breeding season for the olive ridley is between the months of December to April. Turtles migrate from their various feeding grounds, which may be spread across ocean boundaries, and congregate a few kilometers off-shore from their natal beaches for mating. The nesting females use the same off-shore habitat during the 11-15 day inter-nesting intervals between their 2-3 nesting events per season.
It is during this time that breeding turtles may be threatened by accidental interactions with commercial and artisanal fishers and their gear. A high number of dad and live stranded adult olive ridleys are recorded along the east coast between January and March each year. The number of strandings has increased during the past 5 years, which the cause of death believed to be drowning in fishing gear. On 22nd February 2014 and 7th March 2014, there were two widely recorded mass strandings, one in Nellore, Andhra Pradesh, and the second close to the Vellar estuary, Tamil Nadu by TREE Foundation. The combined mortality of those two events was estimated at over 2,000 olive ridley turtles.
Under current regulations, mechanised trawl boats are not allowed to operate within 8km of the shore in Andhra Pradesh, 5.5km in Tamil Nadu, and 5km in Odisha. Trawlers that target shrimp fisheries are required to be fitted with turtle excluder devices (TEDs), yet none of the boats currently use them due to concerns about reduction in catch.
A three day event (20–22 January 2015) was held to introduce trawl boat owners and workers operating from Kasimedu Chennai fishing harbour to the benefits of using TEDs. The demonstration and trials were organized by TREE Foundation in conjunction with the Fisheries and Forest Departments. The members of the trail team comprised of Dr. R Raghu Prakash (principal scientist), V.Kamaraju (TED net-maker) and S. Policeu (technician) from Central Institute of Fisheries Technology (CIFT); Dr. Supraja Dharini, P. Sundeep, V. Hari, and A. Yesudoss from TREE Foundation; N.S.Prem Raj (Fisheries Foreman) and S. Bakthavatsalam from the Coastal Security Group Commandos, Tamil Nadu; Vinod and Nishant (volunteers from Student Sea Turtle Conservation Network (SSTCN)); N. Devarajan (camera-person) and Sekar (assistant cameraman). The Trawl Boat Owners Association was represented by members Arasu, C. Desingu, and 12 trawl fishermen.
After a brief welcome address from G. Ezhulumalai (TREE Foundation senior Sea Turtle Protection Force member), Dr. R Raghu Prakash introduced and explained the use of CIFT-TEDs.
Figure 1 Design of a CIFT-TED.
The CIFT-TED has a circular stainless steel (316 marine grade) hoop with a diameter of 900 mm at the front end of the device. The accelerator funnel attached to the front hoop propels fish and shrimp catch faster towards the cod end. There is an elliptical 1000 x 800mm stainless steel ring (10mm thick) fitted with vertical 8mm deflector bars 150mm apart a further 19m back in the accelerator funnel, at an angle of between 30° and 55°, to assist trapped turtles to the escape flap fixed at the top of the grill. The rings are connected with webbing to a single piece of polythene netting of 40mm stretched mesh size. The single piece of netting that forms the outside of the TED measures 150 x 60 mesh.
Designed by Dr. R Raghu Prakash and a team of CIFT scientists and produced at the Central Institute of Fisheries Technology, Visakapatnam, Andhra Pradesh, the advantages of this indigenously designed TED is that it is interchangeable within 20 minutes among the various net types used by local trawlers. When used, there is a significant reduction in unwanted by-catch so operators do not have to free trapped turtles and sort through by-catch, activities which reduce their fishing effort. The quality of catch is also improves as there are no trapped turtles to crush the fish, and fishers can command a better market price for their catch.
Dr. Prakash’s presentation was followed by a question and answer session. A member of the Trawl Boat Owners Association was apprehensive about the use of the TEDs, not convinced that there would only be a loss of 5% of captured fish. Dr. Prakash explained that he had derived the results from ~500 trawl samples with the TED over 15 years of research (Prakash, pers.comm.).
Other workshop participants, including Mr. M. Mohamed Nainar (Assistant Director, Fisheries Department, Tamil Nadu); Mr. G. Balasubramaniyam (Deputy Superintendent, Coastal Security Police, Tamil Nadu), Dr. S David Raj (Forest Range Officer, Chennai), Commandant S.E.D Anand Kumar (Indian Coast Guard, Region East), encouraged the trawl fishers to have an open mind and trial the TED. They explained that the number of stranded sea turtles have increased dramatically over the last few years, and that the TED would only require seasonal operation between November and March. A short video from ‘Scubazoo’ of a TED in operation and pictures of the two mass strandings of sea turtles that occurred in Andhra Pradesh and Tamil Nadu in 2014 were used as illustrations. The Chennai Chengai Singaravelar Trawl Boat Owners Association, Kasimedu Fishing Harbour, volunteered to provide boats for a trial so fishers could observe the deployment of TEDs at sea.
A CIFT-TED was fitted to the standard trawl net in a trawl boat and two hauls with a 1hr drag period, and a gap of two hours and 5km between hauls, were conducted. No turtles were captured in either deployment, however, a trawl boat operating ~60m from the trial boat caught a live olive ridley turtle (subsequently released unharmed and observed by the author) in the same time period. The sea trial illustrated that minimal loss of fish occurred when using the TED, a concern of many fishers. The scientist present for the trial estimated the likely fish loss during the TED deployment, engaging the fishermen on board for the valuation of weight of each catch. It was estimated that only between 2-3% of the catch escaped from the net fitted with a TED, which surprised the fishers.
After another one hour trawl time, an adult male olive ridley (70cm curved carapace length, 66cm curved carapace width) was observed trapped in the bag attached to the escape flap. This capture provided the observers with an opportunity to understand a TED in operation. The turtle was allowed to recuperate for a few minutes before being gently lowered from the boat and released back into the ocean, much to the delight of those present who observed the turtle to swim off uninjured. Another individual turtle and a pair of mating turtles were also sighted (N:13-11-330, E:080-21-230), demonstrating that the trawler operation area is both an important mating and foraging area and the need to implement TEDs in the fleet.
Having observed both the simplicity and effectiveness of the device, trawl operators are now considering implementing TEDs on their boats. The trials clearly demonstrated that the benefits of using a TED outweighed the initial installation cost of Rs.1,000 that would have to be borne by the operators. The loss of catch for the demonstration was <5%. To date, all TED trials have had a 0% turtle capture rate.
The demonstration and sea trials have been hailed as a positive step towards success by all parties involved, and could mark a turning point in sea turtle conservation in Tamil Nadu. TREE Foundation proposes to conduct surveys measuring the success of the sea trials before the next season. There is a superstition among fishers that catching a turtle brings bad luck, and boats will usually return to the fishing harbour, cutting short their fishing activities for the day, in a turtle is caught then conduct a costly religious ceremony to cleanse their nets and boat. Subsequent awareness and interactive programs with fishing communities have been held since the initial TED demonstration and sea trials (see Table 2).
Table 2. Awareness programs to complement the TED sea trials in Tamil Nadu.
|Date||Venue||Organized jointly with TREE Foundation|
|20-01-15||Jeevarathan Maligai, Kasimdeu||Fisheries Dept., Forest Dept, Coast Guard, Coastal Security Group|
|23-01-15||Mahabalipuram, Kanchipuram||Fisheries Dept.|
|24-01-15||Pazhaverkadu, Thiruvallur||Fisheries Dept.|
|28-01-15||Vengambakkam, Kanchipuram||Coastal Security Group, Fisheries Dept.|
TREE Foundation urgently recommends the Fisheries Department and Forest Department to :
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