3.4.2.1.4. Nest depth
Natural and artificial nests depth was measured by using stiff measuring tape. This measurement was taken to compare the natural nest depth which was made by the
female turtle in nature and artificial depth made by hatchery’s warden human. Natural nests depth was measured during eggs collection by the warden. It was
after few eggs laid and before the adult female turtle buried the eggs cavity. The artificial nests depth was measured before the eggs put into the artificial nest
artificial eggs cavity.
3.4.2.1.5. Nest humidity
Nest humidity was measured by using gravimetry method. Principle of this method was to measure the water content in sediment. The sand nests natural and
artificial nests were sampled and weighed. This initial weight was considered as
wet weight. Then the samples were dried in 100 °C and weighed until the weight was stable. This weight was considered as dry weight. Humidity was obtained by
subtracting wet weight to dry weight and multiplying with 100 as formula i
below, see also Appendix 1c for equipment and materials used. 100 i
3.4.2.1.6. Nest temperature
Temperature of both natural and artificial nests were measured at the upper rim and bottom as well as the surface sand surround, illustrated in Figure 6.
Temperature measurements of natural nests were taken oviposition egg laying. All eggs were relocated to hatchery area. Temperature of the artificial nests were
measured before the eggs reburied into it. Some temperature measurements of artificial nests were not taken from the previously measured natural nests.
Figure 6 Sketch of temperature measurement at natural and artificial nest Daily measurements of sand temperature, at the surface and below surface,
were taken at the hatcheries and at the beach by interval of 2 hours in 24 hours period. The daily temperature of each ten samples at hatchery A with no roof
and hatchery B with Asbestos roof were measured. Shade conditions of each sample in hatchery A with no roof was noted; samples in shaded area SH for
some part of day marked with 1 asterisk and in whole time of day marked with double-asterisk . Then, measured and compared temperature of nests in
shaded area SH and unshaded area US of hatchery A with no roof and beach area, 2 samples each. Four groups of samples which were consist of each sand
under canopy of vegetation VG, shaded area SH, and unshaded area US subsamples were also measured see Appendix 2a-c. The temperature
measurements were using a non contactable Infra-Red Thermometer Voltcraft IR 260-8S with accuracy of 0.1 °C.
3.4.2.2. Near shore habitat
Since seaturtle use two habitats, sea and beach, it is worth to study its potential foraging habitat. In this study, the sea bottom substrate was also
investigated to estimate the food availability and sea surface temperature SST of Pangumbahan coast and adjacent. Sea bottom substrate was visualized into sea
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