Thushan Kapurusinghe, Lalith Ekanayake, M. M. Saman and Deshapriya Saman Rathnakumara
Five species of marine turtle nest on Sri Lanka's shores, including the green (Chelonia mydas), leatherback (Dermochelys coriacea), olive ridley (Lepidochelys olivacea), loggerhead (Caretta caretta) and hawksbill turtles (Eretmochelys imbricata). Four of these species are listed by the World Conservation Union (IUCN) as either critically endangered or endangered, while the olive ridley was recently reclassified as vulnerable (IUCN, 2006; Abreu-Grobois & Plotkin, 2007). Despite protection by national legislation since 1972, marine turtles continue to be exploited in Sri Lanka for their meat and eggs (Hewavisenthi, 1990; Kapurusinghe, 2006). In addition, habitat destruction through coral mining, clearing of coastal vegetation such as mangroves, disturbance of sea grass beds, coastal erosion, non-scientific turtle hatchery practices, insensitive tourism and coastal development, as well as by-catch in artisanal fisheries, all pose unquantified threats to the island’s marine turtle populations (Kapurusinghe, 2006).
The Turtle Conservation Project (TCP) was established in Sri Lanka in 1993 to address uncontrolled and illegal marine turtle exploitation and habitat destruction. Through research programmes, public awareness campaigns and community participation projects, the TCP has initiated a suite of ongoing community-based conservation activities along Sri Lanka's coastal belt to facilitate the conservation of marine turtles and their habitat. These include national and local environmental education programmes, small-scale eco-tourism turtle watching, and mangrove rehabilitation, which were developed at key sites between Kalpitiya in the north-west and Kirinda in the south-east of the country (Kapurusinghe, 2000a).
Project site: Kosgoda village is in the Galle district on the south-west coast of Sri Lanka (Fig. 1) and is the location of one of the most important green and olive ridley turtle rookeries in Sri Lanka (Amarasooriya, 2000). Prior to the establishment of the TCP nest protection project in Kosgoda in 2003, turtle egg collection was an important economic activity for some villagers. All turtle nests deposited at the Kosgoda rookery were harvested by village men for sale at local turtle hatcheries. These egg collectors, known as ‘beach boys’, were either completely dependent or semi-dependent on the sale of marine turtle eggs for income generation (Ekanayake et al., 2007). Since the early 1970s, several turtle hatcheries have been established in and around Kosgoda, and while they serve as popular tourist attractions, due to poor management practices, their contribution to marine turtle conservation is questionable (Hewavisethi, 1993; Kapurusinghe, 2006).
Figure 1. Map showing the TCP in situ marine turtle conservation sites (in red text) in Sri Lanka.
The TCP first began establishing a turtle nest protection project in Kosgoda in late 2003; however, the December 2004 tsunami was a severe blow to the village, claiming life and property and leaving community members mentally and physically traumatized and materially deprived. Many families lost family members, as well as all their possessions and savings of a lifetime. Three nest protectors employed by the TCP lost their lives and most lost their homes, and the TCP office in the village was also destroyed. The tsunami completely swept away turtle nests and stretches of coastal vegetation, leaving the remaining TCP employees in the village without work. Fishermen lost boats and equipment, and subsequently, fish sales remained poor due to the common belief that marine fish would have consumed the human flesh of the drowned disaster victims. Tourism also collapsed, so that most people in the village lost their livelihoods. In addition, vital facilities such as water, electricity, health and sanitary services, as well as key infrastructure such as road and rail systems, were all seriously affected.
With funding from international donors and supporters, the TCP once again established a community-based turtle conservation project in the village some weeks after the tsunami as part of a wider relief programmed for Kosgoda village. The objectives of the programmed were:
- To protect all marine turtle nests located within the project boundaries and ensure that all resulting hatchling turtles reach the sea immediately after emerging from the nest.
- To provide training for local community members in in situ marine turtle conservation and research techniques.
- To provide an alternative and sustainable income to Kosgoda villagers affected by the tsunami and who were previously financially dependent on turtle egg poaching, by employing them within a non-consumptive, sustainable turtle utilisation project through the development of a small-scale turtle watch programmed for tourists.
- To collect biological data from the nesting female populations of marine turtles of each species present at the Kosgoda turtle rookery, by monitoring the number of nests per season (individual and population totals), the size of nesting female populations, growth rates of individuals, longevity of individuals beyond tagging, mean breeding frequency, incubation periods, nest temperatures and hatching success rates (‘in situ’ vs. hatchery comparative studies), migratory paths and geographical range.
In situ nest protection: One full-time Project Site Manager and five full-time TCP Research Officers (ROs) were employed to coordinate, supervise and implement project activities at Kosgoda. Fifteen former turtle egg collectors who had been severely affected by the tsunami were recruited and trained as Nest Protectors (NPs). The training included in situ nest protection and basic biometric data collection methods (e.g. curved carapace length measurement). A 1km stretch of beach within the project boundaries was designated as the project site and selected because of the high turtle nesting density known to occur there. This stretch of beach was then marked with painted wooden posts every 50 metres along the beach vegetation line. Each post was marked with a sequential reference number and these posts were used to generate referenced triangulations of the locations of all nests deposited within the project boundaries. The beach was patrolled 24 hours per day by TCP staff working on a shift basis, with the NPs assisting the ROs at night and patrolling the beach during the day to deter illegal egg collection and natural nest predation. TCP staff liaised with the local Police to enforce the national legislation that protects marine turtles and their nests.
Biometric data collection: At least two ROs and six NPs were present on the beach from 18:00 hrs to 06:00 hrs every night, when patrols were carried out every half hour through the night to locate nesting turtles, starting from a central point where the weighing equipment was placed. When a turtle was located, the team was alerted by an exchange of torch signals. The following data were collected and recorded: time at the beginning of each stage of the nesting process; egg count; diameter and weight of a sample of ten eggs; curved carapace length (CCL) and width (CCW); and each turtle that successfully nested was tagged in each front flipper with a unique, titanium identification tag, bearing a number and the TCP’s address.
The egg count was achieved by one member of the team situating himself directly behind the turtle. When she had finished excavating the egg chamber, he scooped out the rim of the chamber opposite her cloaca; he then inserted one hand into the egg chamber and under the turtle’s cloaca without touching it, holding a mechanical counter in the other hand to count each egg as it fell from the cloaca through his outstretched fingers and into the nest. This method minimised the handling of eggs. The sample of ten eggs was removed from the nest during laying.
While the female turtles covered their nests, a knotted piece of plastic hazard tape was placed over the nest location. After the turtle returned to the seas, the tape was recovered and the exact location of the nest triangulated and recorded using the reference posts at the back of the beach. A one metre square, wide-gauge, metal mesh screen was then placed over the nest and pegged down at each corner. The mesh size is small enough to prevent animal predators from excavating the nest, yet large enough to enable emerging hatchlings to escape. The nest screens would also prevent the excavation of incubating nests by subsequent nesting females. Once the nest screen was in place, the turtle tracks were erased from the sand using a coconut leaf.
The following morning the data were entered into a database (Microsoft Excel) by one of the ROs (Ekanayake et al., 2007).
Here we present simple descriptive statistics with respect to the numbers and seasonality of green and olive ridley turtles at Kosgoda.
|Total number of nests per month|
|Month||2005||2006||2007||Over 3 years|
|January||20 (o/r=4)||49 (o/r=6)||12 (o/r=9)||81 (o/r=19)|
|February||21 (o/r=2)||53 (o/r=7)||17 (o/r=5)||91 (o/r=14)|
|March||33||66 (o/r=3)||29 (o/r=1)||128 (o/r=4)|
|May||51 (o/r=1)||55||41 (o/r=1)||147 (o/r=2)|
|August||7 (o/r=1)||24 (o/r=1)||4||35 (o/r=2)|
|September||11 (o/r=1)||12 (o/r=1)||10 (o/r=1)||33 (o/r=3)|
|October||16||9 (o/r=1)||3||28 (o/r=1)|
|November||21 (o/r=3)||20 (o/r=7)||7 (o/r=3)||48 (o/r=13)|
|December||34 (o/r=8)||12 (o/r=4)||19 (o/r=7)||65 (o/r=19)|
|Total||314 (o/r=20)||417 (o/r=30)||205 (o/r= 27)||936 (o/r=77)|
Table 1. Number of turtle nests recorded during 2005, 2006, and 2007. Number of olive ridley nests contributing to the monthly/yearly totals is shown by (o/r=).
Figure 2. Nesting frequency of marine turtles in Kosgoda between 2005 and 2007.
Figures 3 & 4. Comparison of nesting frequency of green turtles & olive ridley turtles in Kosgoda between 2005 and 2007.
As shown in Table 1, a total of 936 marine turtle nests were laid on the 1km stretch of beach at Kosgoda during 2005, 2006 and 2007. Green turtle nests made up 91.7% (n=859) of the total number of nests while 8.3% (n=77) were laid by olive ridley turtles (see Table 1 and Figs 3 & 4). Over the three seasons, April and May appeared to represent the peak of the green turtle nesting season (see Table 1 and Fig. 2), while December and January appeared to represent the peak of the olive ridley season (see Table 1). No olive ridley nests were recorded during April, June and July, and there were 526 false crawls (unsuccessful nesting attempts) during the study period.
The TCP has established a community-based project at Kosgoda involving 24hr beach patrols that protect nesting turtles and their eggs in situ, and this work has resulted in the successful protection of 936 green and olive ridley turtle nests during 2005, 2006 and 2007. All the nests laid during this time were allowed to hatch naturally and the resulting emergent hatchlings safely made it to the Indian Ocean by themselves. Green turtles are the most abundant nesting marine turtle species found in Kosgoda and olive ridley turtles are the next most commonly encountered species. Although all five species of sea turtle have been previously reported in Kosgoda, there were no records of nests made by any of the other three species within the TCP project boundary during the project period. However, the TCP did receive records of these species nesting beyond the project boundaries during this time, but these eggs were poached or sold to the nearby turtle hatcheries.
Through this project, the TCP trained 15 former egg poachers and designated them Nest Protectors, and with assistance from the Sri Lanka Tourist Board, these men were also trained and licensed as government registered eco-tour guides. These villagers now conduct Turtle Night Watch tours for paying tourists, thereby generating alternative income from non-consumptive use of the turtles and protecting their resources through a more sustainable livelihood, having given up their destructive practices.
In addition to the turtle conservation work at Kosgoda, the TCP has successfully introduced various community development projects in the village. Community Based Organisations have been established to produce and generate income from a number of products including ornamental fish, batik items, and coir mats. The TCP has also implemented other skills development programmes in Kosgoda, including computer classes, English lessons, community library programmes, nature trails, rural medical clinics, model medicinal gardens with free herbal drinks, school lecture programmes, environmental film shows and disaster preparation training. Children’s clubs have been established in order to involve children in the coastal eco-system conservation and management process, providing them with necessary awareness through various educational programmes.
The TCP has also helped to develop important infrastructure within the village, such as the primary school and bus stops. The varied benefits the local community has received (both directly and indirectly) have created a positive attitude towards the TCP within the community; this has been a distinct advantage to the implementation of the TCP’s core marine turtle conservation work, and will be so in the future.
The Turtle Conservation Project would like to thank the British Chelonia Group for their generous support in implementing the community based marine turtle conservation project in Sri Lanka. We also express our gratitude to the Department of Wildlife Conservation and the Sri Lanka Tourist Board for assisting the TCP to continue this project. We appreciate the great support provided by the Kosgoda community in implementing various programmes. We especially thank the UNDP, GEF, SGP, Marine Conservation Society (MCS) and CIDA for providing funds to regain the smile of our Kosgoda community who have been affected by the 2004 tsunami. Finally, we would like to thank the reviewers, including Peter Richardson (MCS), for their helpful comments on earlier versions of this article.
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Testudo Volume Six Number Five 2008