Southeastern Turkey and Cyprus have the largest remaining populations of green turtles (Chelonia mydas) in the Mediterranean (Baran and Kasparek 1989), with less than 400 females estimated to nest annually in the region (Broderick et al. 2002). Samandağ Beach (36°07′–36°01′N, 35°55′–35°58′E) is one of 3 main nesting beaches in Turkey for C. mydas (Kasparek et al. 2001; Canbolat 2004). This study updates the status of C. mydas nesting on Samandağ Beach during 2001–2002, assesses threats, and compares previous studies (Yerli and Demirayak 1996; Yerli and Canbolat 1998).

Methods

The overall length of Samandağ Beach is about 14 km, with nesting areas in 3 separate sections: Meydan Beach, 4.4 km in length; Şeyhhızır Beach, 4.1 km in length; and Çevlik Beach, 5.5 km in length (Fig. 1). Of these, Şeyhhızır Beach is the most important nesting area for C. mydas. Its width varies between 15 and 20 m, narrowing toward the mouth of the Asi River. Artificial sand dunes are important for green turtles in this section. Dune height increases to 1–2 m near the Asi River mouth. Vegetation along the shoreline consists of shrubby plains. Samandağ Beach has no protection status; entry to the beach at night is prohibited because it is a national border area.

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Studies in 2001 were only on Şeyhhızır Beach (due to heavy excavation activities on other sections) and in 2002, studies were on all 3 sections. Observation methodology followed Whitmore and Dutton (1985) and Erhardt (1982). All beaches were patrolled for tracks and nests everyday from 0500 to 0900 hours by 5 volunteer students. Where tracks were seen, symmetrical tracks were attributed to C. mydas and alternating tracks to Caretta caretta. False and real crawl paths were identified. Relations between eggs, hatchling emergence, and predators were examined, and attempts were made to identify predators from their tracks. Other threats were determined by direct observation of the beach and its surroundings and by nest-control studies. Hatchling numbers were estimated by counting hatchling tracks whenever possible. In the week following hatchling emergence, nests were opened to count the empty eggshells and undeveloped eggs. Predated eggs found inside or near the nests were counted. Total number of eggs and hatchlings were estimated by these evaluations.

In 2001, studies occurred from 3 July to 30 September on Şeyhhızır Beach. This section was chosen on the basis of 1996 data (Yerli and Canbolat 1998), indicating that it had the highest nesting density for C. mydas for the entire Samandağ Beach area. In 2002, studies occurred from 28 June to 25 September for all 3 sections of Samandağ Beach.

Results and Discussion

We recorded nesting for C. mydas at Samandağ from 28 June to 11 August, and hatchling emergence from 2 August to 30 September, nearly the same dates reported by Yerli and Demirayak (1996). We recorded 20 nests in 2001 on the Şeyhhızır Beach section, and 118 nests in 2002 on the entire Samandağ Beach.

Distances of nests to the shoreline were recorded as 29.1 ± 16.0 m (range, 8–58 m; n = 17) for 2001 and 28.9 ± 15.1 m (range, 6–76; n = 97) for 2002. Average nest depth and diameter were 77.3 ± 3.9 cm and 28.3 ± 3.3 cm in 2001 and 76.8 ± 10.3 cm and 26.7 ± 4.3 cm in 2002. Some nests were observed in wet sand near the shore; 6 nests in 2001 and 24 nests in 2002 were damaged by erosion and flood.

Nesting data for 2001–2002 are given in Table 1 by month and beach section, respectively. Eighty-four tracks without nesting were observed on the Şeyhhızır Beach section in 2001, 79 of them C. mydas and 5 C. caretta. Most C. mydas returned to the sea without nesting; only 20 (25.3%) nesting successfully. Nevertheless, 14 of these nests survived and hatched. Three hundred eighteen C. mydas nesting emergences were recorded on the entire Samandağ Beach in 2002, with 118 (37.1%) resulting in nests. In addition, 7 C. caretta nests and 2 C. caretta tracks without nests were recorded in 2002. Yerli and Demirayak (1996) recorded 319 emergences of C. mydas on Şeyhhızır Beach, of which 113 resulted in nesting (35%). Nest densities in our study were 4.9 nests/km for 2001 and 8.4 nests/km (22.4 nests/km at Şeyhhızır) for 2002. The nest density was recorded as 23 nests/km on Şeyhhızır Beach in 1994 (Yerli and Demirayak 1996).

Table 1. Nesting data for Chelonia mydas on Samandağ Beach and its 3 sections during 2001–2002.

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Previous data on C. mydas nesting on Samandağ Beach are few. In 1988, 40 nests were found during casual surveys along the entire beach (Baran and Kasparek 1989). In 1994, research concentrated on the Seyhızır section and produced 113 C. mydas nests with a density of 23 nests/km for this core area of the beach (Yerli and Demirayak 1996). In 1996, 44 nests with a density of 5.2 km were recorded on Samandağ Beach (Yerli and Canbolat 1998). A direct comparison between our study (2001–2002) and previous studies (1994 and 1996) cannot be made due to differences between methodologies, but Fig. 2 provides some basis for comparison.

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The number of nests, eggs, hatching success, and survival on Samandağ Beach for 2 years are presented in Table 2. The mean number of eggs in each clutch was 126.6 ± 33.5 (n = 14) for 2001 and 122.0 ± 24.2 (n = 82) for 2002. Yerli and Demirayak (1996) reported that clutch sizes for C. mydas were 118 on Kazanlı Beach, 112 on Akyatan Beach, and 127 on Samandağ Beach. The first hatchling emergences were observed on 2 August, and the last track was observed on 25 September in 2002. On the Şeyhhızır section of Samandağ Beach, we recorded 1773 eggs in 14 nests in 2001 and 10,021 eggs in 82 nests in 2002. Yerli and Demirayak (1996) reported 11,457 eggs and 9930 hatchlings (n = 90 nests) for the same beach section in 1994. Total numbers of hatchlings reaching the sea as a percentage of the total number of eggs laid was 79.5% in 2002. In 2002, 118 nests were recorded and 76 hatched (64.4%); in 2001, 20 nests were recorded and 14 hatched (70%).

Table 2. Observed natural hatching success and survival for Chelonia mydas on the Şeyhhızır section of Samandağ Beach.

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We measured 137 hatchlings on Samandağ Beach. The mean straight carapace length was 4.9 ± 0.45 cm (range 3.7–6.1 cm), and straight carapace width was 3.8 ± 0.39 cm (range 2.7–5.0 cm).

Predation effects were very low on Samandağ Beach. Probably the most effective predation was the result of ghost crabs (Ocypoda cursor). We counted up to 8–15 ghost crabs per square meter concentrated around the nests. Yerli and Demirayak (1996) recorded 5 hatchlings depredated by crabs in 1994 on Samandağ Beach. Stancyk (1982) noted that crabs cannot open or devour eggs, but they can consume already damaged eggs and they frequently burrow in to nests. We did not observe any fox predation, and dog predation occurred rarely.

Tourism affects only the northern part of the Çevlik Beach, around the Şeyhhızır Tomb; establishments in the Deniz neihborhood and Çevlik constitute the recreational developments of the region. Light pollution from houses and restaurants causes some hatchlings to become disoriented.

Most land behind the beach is used for agriculture, and greenhouse farming and citrus fruit production is widespread around the beach. It is unknown whether this agriculture has affected nests and embryonic development.

Sewerage is discharged near the nesting beach causing a foul odor, and no nests or tracks were observed around this area. Moreover, the sewage has caused increasing beach vegetation, which is burned periodically by the local municipality.

Fishing—using many different methods (line, cast nets, trawl)—is an important economic activity in the region. Çevlik Harbor is one of the main fishing centers of the region, and trawl vessels depart from here on a regular basis. Although the coastal fishery is forbidden by law and despite the presence of military forces, it continues in this area.

Illegal sand extraction is also fairly extensive (Yerli and Demirayak 1996; Yalçın 2003; Yalçın-Özdilek and Sönmez 2003). This problem plays a major role in local conservation of sea turtles. In 2001 and the previous nesting seasons, there was extensive sand extraction from the beach during the nesting season. In 2001, we observed that there were many big excavation holes on the beach. It is possible that the low nest number we recorded that season is that many nests could have been taken with the sand. In the second year of monitoring, the sand extraction was decreased by conservation precautions.

Coastal erosion is the biggest threat to the nesting area due to sand excavation in previous years. Artificial sand ridges to protect agricultural land has also created problems for sea turtles. Female turtles have been known to climb over these sandy embankments in their search for suitable places for nesting and have strayed into the fields beyond. Tractor and trailer tracks left on the beach during sand extraction constitute a serious obstacle for hatchlings on their way to the sea. Hatchlings are often unable to climb over these tracks and remain on the beach under the sun to die. Many dead hatchlings were collected from agricultural fields behind the sand ridges during hatching season. Artificial light from associated buildings causes disorientation in hatchlings.

Another major problem is that the beach is covered with garbage (recyclable, medical, hazardous, hard-to-recycle), particularly plastic bags. These solid wastes increase crab predation by causing an obstacle for hatchling turtles attempting to reach the shore. Yalçın-Özdilek et al. (2006) recorded that River Orontes (Asi)—an international river that passes through Lebanon, Syria, and Turkey—is used for all types of waste (including medical and hazardous types) by the city of Antakya and its environs, which brings much solid waste to the shoreline at Samandag. Additionally, coastal communities have long disposed their wastes on the coastal zone, despite that their accumulation is observable along the shoreline. The waste problem of coastal cities in the region and the dumping of wastes by ships should be approached within the framework of international agreements, because the cause of the problem does not stem from a single country.

Conservation Recommendations

We recommend that all sand extraction from Samandag Beach be stopped and a control mechanism be established. Administrators and inhabitants should be informed about the legal and environmental consequences of sand extraction. The remaining sand dunes are in critical condition. There is an urgent need for a dune management plan to stop erosion, rehabilitate damaged areas, and protect the agricultural lands nearby. The grazing of animals, burning of vegetation, and depositing of wastes on the sand dunes should be strictly forbidden. Dunes should be protected by natural materials, such as rushes and reeds, until the natural vegetation grows back. Vehicles should not be allowed on the beach. The effects of the Deniz neighborhood development on erosion should be evaluated by coastal geomorphologists and engineers, and a plan to correct and mitigate damage should be prepared immediately. The beach should be cleaned regularly and monitored throughout the nesting season. Lights in houses on Seyhhızır Beach should be screened, especially during the hatching season.