Marine Turtle status Report - Indian Ocean - South-East Asian ...

Semporna PCA is home to Malaysia’s largest concentration of coral reefs, which isa natural capital for reef fisheries and lucrative dive tourism. Marine turtles areclosely associated with coral reefs and found throughout the PCA, making theman attraction for divers and snorkelers.Poaching of eggs was identified by the Mataking and Pom-Pom resort operatorsand Datu Pengiran of Pandanan as one of the major threats to turtles in the area.They alleged that the eggs were poached by fishermen and enforcement agencypersonnel for food. The erosion of nesting beaches on all six islands was observedto be an increasing threat as suitable nesting sites become scarce. Turtlehatcheries have been built to address perceived and identified threats such asnatural predators (monitor lizards, ghost crab and ants). The hatcheries enabledeasy and efficient monitoring and protection of turtle nests and eggs.Hatching success rate refers to the numbers of hatchlings that hatch out of theirshell which equals to the number of empty egg shells in a nest (Miller, 1999).Eggs should be handled carefully. All handling (excavating, measuring, weighing,transporting, reburial) of eggs should be completed within two hours ofoviposition. Otherwise the eggs should be allowed to remain in situ for at least 25days to reduce the impact of movement-induced mortality (Limpus, 1994b;Limpus et al., 1979 as cited in Miller, 1999; Parmenter, 1980 as cited in Miller,1999). The lowest hatching rates for Green turtles in Mataking in 2007 may beattributed to improper handlings of the eggs. More training in monitoring andegg handling should be implemented. An 80% success hatching rate of eggsincubation is recommended for all states in Malaysia (Department of FisheriesMalaysia, 2008). A minimum of 70% of eggs in a clutch have to be protected tokeep turtle populations functional (Limpus, 1994a).Improper handling of eggs is not the only factor affecting hatching rates. Infertileeggs were found to be one of the causes of Terengganu’s declining Leatherbackturtle population (Kamarrudin, 1994). Leh (1991 as cited in Leh, 1994) also notedthat infertile Green turtle eggs in Sarawak Turtle Islands in addition to improperhandling were another reason for low hatching success rates.In Baguan Island Marine Turtle Sanctuary hatchery, Yaptinchay & de Veyra(1994) found that hatching success was not affected by shading and spacing ofnests. There was an increase in hatching success when clutch size was alteredfrom natural (average 100) to a range of 60-80 eggs regardless of shading.Hatching success decreased when eggs were mixed from different clutches,compared to an unmixed clutch regardless of shading or smaller size of eggchamber.Hatching success and causes of mortality can be determined when the nest isexcavated and analysed after the natural emergence of hatchlings. Mortimer(1990) recommended several ways to improve management of hatcheries inSarawak by achieving hatching success of green turtle eggs of 80 to 90%. It wasrecommended that eggs be re-buried in the hatchery within three hours after they37