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
bottom classification map by using Landsat 7 ETM+ satellite image. The sea
surface temperature SST was visualized by using ODV Ocean Data View. 3.4.2.2.1.
Sea bottom substrate
First step in creating sea bottom classification map was to download Landsat
satellite image.
Landsat 7
ETM+ was
downloaded from
http:edcsns17.cr.usgs.govEarthExplorer
.
August 28
th
2011 acquisitioned Landsat 7 ETM+ image data extension of ers. and Lyzenga equation see ii
were used for image digital data processing. Then, filled the empty data in some image with August 27
th
1999 data acquisitioned. Afterward, ER Mapper 6.4
software was used to overlay each band.
The overlaid image was cropped based on study area range see Table 5. There are some corrections which should be applied in general mapping creation,
i.e geometric and radiometric correction. Geometric correction was not applied in this particular map because the downloaded image has already been corrected.
Radiometric correction was applied by using histogram adjustment technique. This correction was done in order to reduce noises due to atmospheric influence.
Band composite was applied for classification process by RGB 421 combination. This RGB combination was used to recognize living coral area
which would be represented in cyan color. Then, training area of sea bottom substrate was created and classified with supervised Maximum Likelihood
Standard Classification MLSC. The supervised result was overlaid with land which has been composited with RGB 321. Last step was to create bottom
substrate classification map by using ArcGIS 9.3 software to visualize the sea bottom substrate. Band characteristic is presented in Table 6.
Lyzenga equation 1981, in Arief et al. 2010: ln
ln ii
Y : depth invariant index
ln bi : normalized image in band i
ln bj : normalized image in band j
kikj : ratio of attenuation coefficient 17
Which, a a
1 iii a
+
,,
iv
-
ii
: Variance of band i -
jj
: Variance of band j -
ij
: Covariance of band ij
Table 5 Coordinate of study area
longitude Latitude
Location 106.38983
-7.3237778 Pangumbahan Pos 5
106.39214 -7.3260556
Pangumbahan Pos 4 106.39475
-7.3283611 Pangumbahan Pos 3
106.39767 -7.3313611
Pangumbahan Pos 2 106.39808
-7.3350556 Pangumbahan Pos 1
106.38767 -7.3220278
Pangumbahan Pos 6 106.37389
-7.3091667 Batu Kereta beach
106.37103 -7.2808889
Catigi beach 106.38767
-7.3220278 Ujungan 1
106.374 -7.3093889
Ujungan 2 106.48625
-7.3753611 Cikarang 1 estuary
106.48925 -7.3769722
Cikarang 2 estuary 106.37344
-7.3061389 Penyu 1 beach
106.37322 -7.3038056
Penyu 2 beach 106.37444
-7.3030833 Karang Dulang 1 beach
106.37506 -7.3009722
Karang Dulang 2 beach 106.37578
-7.3001389 Citirem 1 beach
106.37189 -7.2850556
Citirem 2 beach 106.51272
-7.39775 Minajaya 1 beach
106.52364 -7.4078889
Minajaya 2 beach 106.67722
-7.42475 Cikaso 1 estuary
106.68797 -7.4259167
Cikaso 2 estuary
