Status of the Nile Soft-shelled Turtle, Trionyx triunguis, in Turkey.
An assessment in the Çukurova Delta With Recommendations for Conservation Management Report for the 20th Meeting of the Standing Committee of the Convention on the Conservation of European Wildlife and Natural Habitats (Bern Convention) Report prepared by Max Kasparek in co-operation with the LIFE Project of the EC. “Çukurova Delta Biosphere Reserve” Commissioned by MEDASSET The Mediterranean Association to Save the Sea Turtles September 2000.
INTRODUCTION. The Bern Convention and Trionyx triunguis. The Nile Soft-shelled Turtle, Trionyx triunguis, occurs in the eastern Mediterranean. The main populations are found in Turkey and Israel, with a few smaller populations in Egypt, the Lebanon and Syria. The species is seriously threatened. It has been estimated that the total Mediterranean population does not exceed 500 adults (Kasparek & Kinzelbach 1991). The species has been included in Appendix II of the “Convention on the Conservation of European Wildlife and Natural Habitats” (Bern Convention) on the 16th Meeting of the Standing Committee, 2-6 December, 1996. The Convention dealt with the Nile Soft-shelled Turtle, Trionyx triunguis, in its “Recommendation No. 26 (adopted on 6 December 1991) on the conservation of some threatened reptiles in Europe”. In this recommendation, the Standing Committee “recommends that the Government of Turkey: ! ensure, by most appropriate means, protection of all important populations of Trionyx triunguis by protection of the Dalaman delta and the maintenance of the clean and pristine catchment of its river; ! ensure protection of Seyhan and Ceyhan lower rivers with sufficient conservation measures to prevent adverse developments; ! ensure protection of the Dalyan delta and prevent sewage discharge and damage by powerboats; ! investigate and offset adverse affects on the species of fish traps and persecution;” During a progress review in 1994, the Government of Turkey reported both achievements and difficulties in putting this Recommendation into practice. A Group of Experts subsequently decided that Recommendation no. 26 should remain valid and should be considered as a national priority. The Trionyx issue was again on the agenda of the Standing Committee Meetings in 1996 and 1997, but no considerable progress in the protection of this species could be demonstrated. The report by the Turkish Government in the 1999 Meeting of the Standing Committee of the Bern Convention (T-PVS(99)31) showed again that some deliberations on protection measures were made by the concerned ministry, but no practical steps towards conservation were taken. In order to support conservation of this highly threatened species, since 1998 MEDASSET has initiated field surveys along the Mediterranean coast of Turkey, assessments of the
MEDASSET: Status of Trionyx triunguis in the Çukurova Delta, Turkey (2000).
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species conservation needs, and has been elaborating recommendations for conservation and management to the Standing Committee Meetings. In August 2000, another field survey was carried out in the Çukurova Delta area in cooperation with the LIFE Project “Çukurova Delta Biosphere Reserve” of the EC, in order to assess the occurrence of the species and its conservation needs (Addendum 1, Map).
OCCURRENCE OF TRIONYX TRIUNGUIS IN THE ÇUKUROVA DELTA. Ceyhan River. During the survey in August 2000 two large individuals of Trionyx triunguis were observed approx. 2-3 km above the river mouth. Fishermen reported the species’ continuing presence in the lower river course. Sand dunes along the river banks were identified as a nesting area. Discarded egg shells were found and several local people confirmed that nesting takes place there on a regular basis. The nesting area extends over the eastern and northeastern river bank, from approx. 3 to 6 km upstream from the river mouth. Local people also reported the occurrence of soft-shelled turtles in oxbows of the Ceyhan River. However, no turtles were found there during this survey and the reports need confirmation. All fishermen interviewed were familiar with Trionyx. The species is known as an aggressive animal that destroys fishing nets and traps. However, killing of soft-shelled turtles apparently does not often occur, as fishermen are afraid of them and it was said mostly escape from the fishing traps and nets, after destroying them. A large, dead adult soft-shelled turtle was found close to the river mouth. No traumas were observed, but slightly reddish stripes on the sides of the neck may indicate that the turtle had been caught in a fishing trap and drowned. The species has already been recorded in Ceyhan River: groups of two to five individuals were observed near the village of Bebeli in 1987 (Kasparek & Kinzelbach 1991). Karatas Drainage Channel. According to local fishermen, soft-shelled turtles are regularly seen close to the channel mouth. The channel crosses sand dunes before reaching the sea, and these dunes offer many nesting opportunities. Further nesting opportunities are present all along the lower course of the drainage channel, as the mud and sand from the dredging of the channel has been deposited along its banks. A large, dead Trionyx drifted down the drainage channel in August 2000, was subsequently washed ashore to the east of the channel mouth. The animal could not be examined, but local fishermen believed that it was unintentionally killed by dynamite fishing. Dead soft-shelled turtles had previously been found in the area around the mouth of the drainage channel, in 1987 and 1988 (Kasparek & Kinzelbach 1991). Tuzla Drainage Channel. According to local fishermen, in addition to being present in the channel itself, Trionyx is apparently also regularly found in the sea immediately surrounding the mouth of the channel. As the channel banks provide hardly any nesting opportunities, it sounds reasonable that soft-shelled turtles enter the sea and nest on the beach close to the channel mouth. In particular, good nesting opportunities are found on the western side of the mouth, and this is the location shown by local people as the favourite site for soft-shelled turtles. Previous records for the area around the mouth of the drainage channel and the nearby sea shores (around Tuzla and Akyatan) stem from 1965, 1967, 1976, 1987, and 1988 (Kasparek
MEDASSET: Status of Trionyx triunguis in the Çukurova Delta, Turkey (2000).
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& Kinzelbach 1991). They all, however, refer either to dead individuals or to observations in the sea. Seyhan River. Seyhan River apparently carries the largest population of soft-shelled turtles within the Çukurova region. Some large individuals were observed on several occasions in August 2000, and additional information was received from fishermen and other local people interviewed. According to this information, the main area for Trionyx is the lower river course, from the river mouth to some 1 km upstream. However, they also occur up to some 9 km upstream, around the mouth of the drainage channel into the river, in the drainage channel itself, and in the river up as far as Baharli village. The area where the river meets the sea provides sandy areas where soft-shelled turtles can nest. Local people reported that in this area they saw both adult and young turtles on many occasions. Additionally, in the lower course of the river there are several muddy and sandy places that may provide nesting opportunities. The drainage channel that joins the Seyhan River below Baharli village carries untreated sewage from the City of Adana ( approx. 1 million inhabitants), and which includes a great amount of organic waste from animal production, in particular feet of chickens. Soft shelled turtles frequently feed on this waste. The occurrence of the Nile soft-shelled turtle in the Seyhan area was first noted by Gruvel (1931), who mentioned offshore capture. Records of single individuals come from 1987 and 1989 (Kasparek & Kinzelbach 1991). Berdan River. Soft-shelled turtles occur in small numbers between the river mouth and 1-2 km upstream. They do not usually occur further up the river than the suspension bridge, between Kulaki village and Tarsus beach. The lower river crosses the sand dunes giving many nesting opportunities. The soft-shelled turtles, however, have first to penetrate a narrow, but dense belt of reeds growing along the riversides. There are previous records dating back to 1987, of a large individual in the river and two individuals in the sea close to the river mouth (Kasparek & Kinzelbach 1991). Dead softshelled turtles were found on Kazanli beach (some 10 km west of the river mouth) in 1988, 1989, and 2000 (Kasparek & Kinzelbach 1991, Demirayak 2000) which can apparently be attributed to this river.
OCCURRENCE OF TRIONYX TRIUNGUIS IN THE SEA OFF THE ÇUKUROVA DELTA. Some sporadic records exist of Trionyx triunguis occurrence in the sea off Çukurova (Kasparek & Kinzelbach 1991). A systematic study was carried out by Oruç, Demirayak et al (1997) during the fishing seasons 1995/1996 and 1996/1997. They accompanied trawlers at sea and recorded all captured turtles. During the 1996/1997 season they logged 437 adult Nile soft-shelled turtles caught in the trawling nets. Particularly large numbers were caught during the winter months. The highest numbers were recorded during December, with 107 soft-shelled turtles caught in two days, 16-17.12.1996. 69% of all soft-shells were caught st th th th in the period between 1 Dec. to 28 Feb. only 14% between 15 Sept. and 30 Nov., and st 17% between 1 Mar. and 15th May. These results show two things, that soft-shelled turtles are not rare in the sea, in particular during the winter months, and that trawl fishing is a real threat to the soft-shelled turtle population. Also that trawl fishing may have a much higher impact on turtle population than the occasional killing of turtles by fishermen, due to interference with fish traps.
MEDASSET: Status of Trionyx triunguis in the Çukurova Delta, Turkey (2000).
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CONCLUSIONS AND REMARKS ON THE ÇUKUROVA POPULATION. The Nile soft-shelled turtle is a relatively secretive creature; it has been observed in the Çukurova Delta in the Ceyhan, Seyhan and Berdan rivers, and also in the large drainage channels of Karata and Tuzla. These populations are among the largest in the Mediterranean. Thus the construction of the drainage channels in the past may have had a positive impact on these populations by creating new habitats. The largest population within Çukurova is to be found in the Seyhan River and in the confluent Seyhan Drainage Channel. The river and the channel are extremely polluted, as they carry sewage and garbage from Adana metropolis. Soft-shelled turtles feed particularly on discarded hen’s feet drifting down the channel regularly. Although this provides an excellent feeding opportunity, the extreme pollution may have disastrous long-term effects on this population. Soft-shelled turtles compete with fishermen for fish. The turtles often destroy fishing nets and traps. Therefore, they are occasionally killed by fishermen, but turtles usually escape after they have destroyed the nets and traps. The effect of trawling in the open sea is regarded as a major threat to soft-shelled turtle populations. Many soft-shelled turtles seem to spend the winter in the open sea, and during this period, many trawling boats are active and causing considerable damage to turtle populations. The use of Sea Turtle Excluder Device (TED) is recommended, to avoid killing large numbers of soft-shells.
OVERALL STATUS OF TRIONYX TRIUNGUIS IN TURKEY. According to our current knowledge of the occurrence of soft-shelled turtles in Turkey, the populations can now be classified as follows: Category I: Largest population with the highest conservation priority
Dalaman Seyhan
Category II: Relatively large populations in urgent need of conservation measures
Dalyan Aksu / Acysu Anamur Göksu Berdan River Tuzla Drainage Channel Karata Drainage Channel Ceyhan River
Category III: Relatively small populations, requiring conservation measures for their survival
Patara Fethiye (information insufficient) Köprü Çayi/Acisu Bozyazi (latest information from 1988) Orontes (Asi) River (no recent information)
RECOMMENDATIONS FOR CONSERVATION AND MANAGEMENT. It was found that the largest populations of Trionyx in Turkey occur in the Dalaman area and in the Seyhan River (Category I populations). Whereas the habitats in the Seyhan River seem to be relatively safe, the Dalaman River habitats are highly threatened by a number of factors, described in detail in T-PVS (98) 59. The population of the Seyhan River in the
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Çukurova, is threatened by trawl fishing at sea during the winter, and by potential long term effects of extreme pollution by sewage from the city of Adana. Detailed Recommendations have been elaborated for the Dalaman area in T-PVS (98) 59: The Dalaman population is one of the two largest populations, and is the most threatened.
Regarding the Dalaman population, it is recommended that the Government of Turkey:•
avoids any tourist or other development of the beach around the mouth of Kükürt Gölü, in particular the construction of any marina
•
takes immediate steps to stop the discharge of waste water from the Incebel summer village into the Kükürt Gölü, thus avoiding further eutrophication of the lake
•
cleans the most polluted parts of the lake by artificially increasing the circulation of water in the lake (prepare a hydrological feasibility study prior to practical action)
•
ensures that the road along the north-eastern shore of Kükürt Gölü has no negative impact on the soft-shelled turtle population (Any disturbance, up-grading, repair of the road, lifting of the closure to Incebel summer village, should be totally avoided)
•
considers, if appropriate and feasible, legal action against the owners and managers of Incebel summer village, for the pollution they cause to the natural water bodies around the summer village
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immediately stop all fishing (with nets, lines, guns, and dynamite) within Kükürt Gölü, Kargin Gölü, and in Tasliçay
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stop the ongoing construction of buildings on the peninsula, south-west of Incebel summer village, between Kükürt Gölü and Tasliçay channel, and within the coastal wetland to the south of Kükürt Gölü
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strictly limit the use of boats in Tasliçay channel, between the Incebel summer village and the sea
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rehabilitates and creates nesting habitats (which may also serve as basking sites)
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clear the sand dune in the south-east of Kükürt Gölü of vegetation (clear the scrub between the dune and the water, if necessary). An area where soft-shells can easily approach the dune should be selected, and an area of some 20x5 m of clear sand dune should be provided
•
widen the southern arm of Kükürt Gölü towards the beach and clear the vegetation
•
accumulate sand in areas that are free from human disturbance, where soft-shells may lay their eggs. Possible candidate areas for the creation of artificial nesting sites are the peninsula between Kükürt Gölü and Tasliçay channel, some areas on the northern shore of Kükürt Gölü, and at the northern edge of Kargin Gölü
•
all rehabilitation measures have to be taken under scientific supervision, and after undertaking a feasibility study. It is particularly important to avoid any habitat destruction and significant disturbance to the species by the proposed measures.
•
make sure that the interchange between the sub-populations of Kargin Gölü and Kükürt Gölü is always possible (keep at all times, the connection of Kargin Gölü with Tasliçay clear of vegetation and free from fishing).
•
declare Kükürt Gölü, Kargin Gölü and adjacent wetlands a protected area, and monitor the effectiveness of protection measures on a regular basis.
Regarding the Seyhan population, it is recommended that the Government of Turkey. •
take immediate steps to control trawling, which is annually responsible for the death of thousands of Nile soft-shelled turtles in the Çukurova area.
•
take steps to stop sewage pollution from the metropolis of Adana.
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REFERENCES. Baran, I. & M. Kasparek (1989): Marine Turtles Turkey. Status Survey 1988 and Recommendations for Conservation and Management. – WWF. Heidelberg. Gramentz, D. (1990): Beobachtungen an der Afrikanischen Weichschildkröte Trionyx triunguis (Forskal, 1775) in der Türkei. – Herpetofauna 12: 22–25. Gramentz, D. (1993): Beobachtungen und Untersuchungen zur Ethologie und Ökologie von Trionyx triunguis in West-Anatolien. – Salamandra 29(1): 16-43. Gruvel, A. 1931. Les états de Syrie. Richesses marines et fluviales. Exploitation actuelle – avenir. – Paris, 453 pp. Kasparek, M. (1994): Die Nil-Weichschildkröte – eine stark bedrohte Reptilienart im Mittelmeergebiet. – Herpetofauna 16: 8–13. Kasparek, M. & R. Kinzelbach (1991): Distribution and bionomics of the Nile Soft-Shelled Turtle, Trionyx triunguis, in the Eastern Mediterranean. – Zeitschrift für angewandte Zoologie 78(2): 137–159. MEDASSET (1998): Status of the Nile Soft-shelled Turtle, Trionyx triunguis, in Turkey with Recommendations for Conservation. - Convention on the Conservation of European Wildlife and Natural Habitats, Document T-PVS (98) 59. Oruç, A., Demirayak, F, et al, 1997. Trawl Fisheries in the Eastern Mediterranean and its Impact on Sea Turtles. WWF International & DHKD, Istanbul. Yerli, S. V. & A. F. Canbolat (1998): Özel Çevre Koruma Bölgelerinde Deniz Kamlumbaalarinin Korunmas1na Yönelik Yönetim Plani Ilkeleri. - Turkish Ministry of the Environment. Yerli, S. V., A. F. Canbolat, H. Ulug & O. Doan (1998): Bat1 Akdeniz Bölgesi’nde Deniz Kampulbagalarinin Korunmasina Yönelik Yönetim Plani Ilkeleri. - Turkish Ministry of the Environment. Yerli, S. & F. Demirayak (1996): Marine Turtles in Turkey: A Survey of Nesting Sites and Status. _ Doal Hayati Koruma Dernei, Istanbul.
Dr. Max Kasparek Mönchhofstr. 16, 69120 Heidelberg, Germany Tel. +49 (6221) 475069, Fax +49 (6221) 471858 Email: Kasparek@t-online.de
ENVIRONMENTAL SITUATION AND TECHNICAL REPORTS PRESENTED BY MEDASSET TO THE STANDING COMMITTEE TO THE CONVENTION ON THE CONSERVATION OF EUROPEAN WILDLIFE AND NATURAL HABITATS (BERN CONVENTION) AT THE COUNCIL OF EUROPE, PUBLISHED UNDER T-PVS REFERENCE: T-PVS (98) 59: Specific Sites, Status of the Nile Soft-shelled Turtle, Trionyx triunguis, in Turkey, with Recommendations for Conservation, 9 pages. T-PVS (99) 73: Specific Site, Trionyx triunguis in Turkey, update report and review, 7 pages.
MEDASSET: Status of Trionyx triunguis in the Çukurova Delta, Turkey (2000).
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