MTN 44:4-6 Sea Turtle Conservation in Cyprus

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Sea Turtle Conservation in Cyprus

Andreas Demetropoulos and Myroula Hadjichristophorou
Department of Fisheries, Nicosia Cyprus

As a result of human activities, sea turtle populations have declined throughout the world to the extent that all the species have been declared by the International Union for the Conservation of Nature (IUCN) as Vulnerable or Endangered. All sea turtle species are now banned from commerce between signatory countries by the Convention on International Trade in Endangered Species of Wild Fauna and Flora (CITES), which Cyprus has ratified. In addition, sea turtles and their eggs have been protected by Cyprus law (Regulations made under the Fisheries Law, Chapter 135) since 1971.

Two species, the green turtle (Chelonia mydas) and the loggerhead (Caretta caretta), have been found to nest regularly on the beaches of Cyprus. It is likely that both species were more abundant historically than they are today. Though records are sparse, older fishermen confirm this contention, and so does the toponomy of at least one area, Chelones, a fisherman's cove in the Karpas adjoining an area of extensive sandy beaches stretching to Cape Andreas. Several leatherback turtles (Dermochelys coriacea) have been recorded off the west coast of Cyprus, though local nesting by this species has yet to be reported.

A thorough survey of sea turtle nesting beaches in Cyprus was undertaken in 1976-1977. Results showed that the green turtle now breeds almost exclusively on the desolate, surf-swept beaches of the west coast, north of Paphos, mainly in the Lara area. Loggerhead turtles breed on most beaches that provide some "privacy" after midnight. Surveys undertaken since have confirmed these initial observations. In 1978, a sea turtle conservation project was launched by the Fisheries Department. It was financed during the first two years by the Cyprus Government. Late in 1980, supplementary monies became available from the World Wildlife Fund and the IUCN.

The Turtle Conservation Project in Cyprus has showed that the nesting season extends from mid-June to mid-August. Turtles deposit 4-5 clutches of eggs per annum and return to nest approximately every three years. There is an estimated breeding population of 100 green turtles in the Lara area; the loggerhead population is apparently larger. Nesting is nocturnal, nest depth is 18-36 inches, and clutch size is about 100 eggs. Incubation lasts 7-8 weeks, after which time the hatchlings emerge nocturnally and infallibly orient toward the sea.

In 1978, a seasonal station and hatchery were established at Lara. Eggs were collected and reburied in the sand (duplicating the original nest), or incubated in polystyrene boxes. About that time, research on terrapins showed that incubating turtle eggs in polystyrene boxes held the potential for biasing hatchling sex ratio, since sex determination in embryonic terrapins was dependent upon ambient temperature. In light of later data suggesting that the incubation of sea turtle eggs in polystyrene boxes produces predominately male hatchlings (Mrosovsky and Yntema, 1980; Mrosovsky, 1982), the use of polystyrene boxes declined at Lara. Recently, however, work has been carried out in glass tanks under controlled temperature conditions with very good results.

Hatching success has improved considerably with experience and better handling techniques. The hatchery now yields an admirable 70% hatching rate. Nonetheless, the hatch rate of undisturbed nests is 80-90% and, for this reason, nests are left in situ as often as possible and protected only by cages.

Foxes are responsible for most natural depredation. On a survey of the beaches east of Polis, more than 70% of the nests were found to have been excavated and the eggs eaten by foxes. Of the nests not disturbed at deposition, most were found to have been excavated upon hatching (foxes apparently follow the trail of the hatchlings back to the nest). Other predators include crows, hawks and ghost crabs. In addition, in Cyprus sand extraction and the commercialization of beaches have deprived turtles of their breeding grounds; and the occasional slaughter of a turtle for its shell has also reduced populations. Some turtles are drowned or are killed when caught in fishermen's nets.

We hope to enhance the sea turtles' prospects for survival in Cyprus by continuing to protect nests from predators. More than 1500 hatchlings were released in 1978. Since then, about 3500 hatchlings have been released per annum. Raising turtles to larger sizes before release (known as "headstarting") is currently under consideration. About 100 turtles, ranging from one to six years old, are being kept in sea cages in Paphos Harbour and in special tanks (courtesy of Nicosia); we are investigating their nutrition and hygiene. Turtles are tagged upon release so that they can be identified if and when they return to Cyprus beaches to nest as adults. Although the concept of headstarting is still a controversial one, it seems likely that releasing turtles of larger size than hatchlings reduces their mortality at sea.

It is often said that turtles have a "lost year", because scientists do not know what happens to the little turtles for the first year or so of their lives. Therefore it is interesting that several hatchlings and some young juveniles have been found in Paphos Harbour, or sighted or caught off the Paphos coast. These are signs that bode well for the green turtle in Cyprus.

Mrosovsky, N. 1982. Sex ratio bias in hatchling sea turtles from artificially incubated eggs. Biol. Cons. 23:309-314.

Mrosovsky, N. and Yntema, C. L. 1980. Temperature dependence of sexual differentiation in sea turtles: implications for conservation practices. Biol. Cons. 18:271-280.