Figure 5 Line intercept sampling method van Laar and Akça, 2007. Lines stretched along the outer vegetation as long as 50 meters black stripes
with intervals of 50 meters along the outer vegetation dash line. Extensions were made a few meters inside the vegetation where the nest
frequently found. Note: Hatchery A: open cage hatchery; hatchery B: Asbestos roofed hatchery; UC: under canopy area; NC: No canopy area
and HWM: near High Water Mark area
Shade areas of hatcheries were not quantitatively measured in detail like in nesting beach. It was only qualitative observation. There were four hatcheries
facilities with different canopy. Two hatcheries were not built with roofs which were patchily shaded by vegetation canopy. The rest were built with roof, one was
built with asbestos roof and the other was with fiber roof. The roof provides shade evenly at all time of day.
3.4.2.1.3. Substrate of beach and nests
Surface sand was sampled at each beach segment, natural nest and artificial nest in order to get information for its grain size composition. Sand grain size
composition of Pangumbahan nesting beach was sampled at each beach segmentPos. Especially for Pos 2, samples were taken twice, Pos 2 left hand side
of the hatchery 2A and at right hand side of the hatchery 2B. Sand sample were taken at under canopy area UC, without canopy area NC and 1 sample at
near high water mark HWM. 13
The samples were taken by using a shovel at 0-10 cm sand depth. It was stored and labeled into separate ziplock bags. First batch of sample analysis were
done in Soil department, Faculty of Agriculture-Bogor Agricultural University. The rest batch was done in Environment laboratory of Aquaculture Department,
Faculty of Fisheries and Marine Science-Bogor Agricultural University. Pipette method Sudjadi et al., 1971 was applied to analyze 7 fractions of
sand grain size composition Table 4. First step was to dry the sand samples in oven 50°C for 1 day. After that, took a few portion of the sample and sieved with
5 fraction sieve then removed to glass plate and weighed each sorted fraction of the sand. The finest sorted sand 0.1 mm moved to a beaker glass and added by
25 ml H
2
O
2
10 then kept in room temperature for 1 night. The next day, the samples were added by 25 ml H
2
O
2
30 and heated for some minute until the bubbles were reduced then cooled it down. Prepared and weighed porcelain plates.
Sieved the samples by using 0.05 mm filter sheet and filtered by water. The sorted sand removed to a porcelain plate and dried in 190 °C oven to get the very find
sand. Silt and clay was contained in filtered solution. The filtered solution was removed into measuring glass, add water up until 400 ml. Shook the measuring
glass by turned it upside down for 10 times and waited for 20 seconds then removed 20 ml with pipette into porcelain plate, dried it in 190 °C oven to get the
silt. Rested the solution for 3.5 hours to be removed as much as 20 ml and dried as well to get clay content. The dried porcelain plates were weighed on Ohauss
analytical digital scale with accuracy of 0.00001 gram. Equipments and materials were presented in Appendix 1b.
Table 4 Sand grain size using Wentwoth scale USDA soil textural classification system
Fraction Diameter limits mm
Name of soil separate I
2.00 - 1.00 Very coarse sand
II 1.00 - 0.50
Coarse sand
III 0.50 - 0.25
Medium sand
IV 0.25 - 0.10
Fine sand
V 0.10 - 0.05
Very fine sand
VI 0.05 - 0.002
Silt
VII Less than 0.002
Clay Source: http:soils.usda.govtechnical handbookcontentspart618.html
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
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
Table 6 Landsat 7 ETM+ band characteristic.
Band Number Spectral Range microns Ground Resolution m 1
0.45 to 0.515 30
2 0.525 to 0.605
30 3
0.63 to 0.690 30
4 0.75 to 0.90
30 5
1.55 to 1.75 30
6 10.40 to 12.5
60 7
2.09 to 2.35 30
Pan 8 0.52 to 0.90
15 Source: http:geo.arc.nasa.govsgelandsatl7.html
Table 7 Landsat 7 ETM+ image data characteristic Swath width:
185 kilometers
Repeat coverage interval: 16 days 233 orbits
Altitude: 705 kilometers
Quantization: Best 8 of 9 bits
On-board data storage: ~375 Gb solid state
Inclination: Sun-synchronous, 98.2 degrees
Equatorial crossing: Descending node; 10:00am +- 15
min. Launch vehicle:
Delta II Launch date:
April 1999
Source: http:geo.arc.nasa.govsgelandsatl7.html
3.4.2.2.2. Sea surface temperature
Distribution of monthly day and night sea surface temperature SST in 2010–2011 at Pangumbahan beach and adjacent coasts were obtained from Aqua
Modis satellite images level-3 with 4x4 km resolution. These image data were available
in National
Aeronautic Space
Agency NASA
website http:www.oceancolor.gsfc.nasa.gov. The raw image data then cropped and
extracted into .ascii data format with Seadas 5.2.0. program. The .ascii data were copied into Microsoft Excel 2007 spreadsheets to be furthermore to be saved
into .txt data format and visualized them in Ocean Data View ODV 4 program. Population and nest temperature data were compiled and processed in Microsoft
Excel 2007 and Statistica 6.0 program. Statistical significance tests were done by using XLstat program.
3.5. Statistical Analysis
Population and nest temperature data were compiled and processed in Microsoft Excel 2007 and Statistica 6.0 program. Statistical tests were done using
XLStat program. Normality test were done in four method i.e. Shapiro-Wilk, Jarque-Bera, Anderson-Darling and Lilliefors tests at the significance level of α =
0.05 for natural and artificial nests temperature. Two-tailed tests were used to compare natural and artificial nests temperature datasets at the significance level
of α = 0.05 and α = 0.01. Two tailed tests were conducted to define the means difference between two datasets McCleery et al., 2007.
4. RESULT AND DISCUSSION
4.1. Nesting habitat
4.1.1. Nesting beach characteristic
Pangumbahan beach is considered to be a high energy beach which directly connected to Indian Ocean. The beach ranged about 2.3 km length and divided
into six beach segments, Pos 1 – 6 see Figure 5 8. Each beach edge Pos 1 and 6 were bordered by small estuary which discharging freshwater into the sea at
wet season and is dry at dry season. The beach was not completely secured from the local activities. There was open access into Pos 1, 5 and 6. Sea pandan
Pandanus tectorius was predominant beach vegetation and creeper plant such as Cyperus pedunculatus
and Ipomoea pescapre patched in some part of the beach. Beach width and slope varied within the whole area. Beach sand is dominated by
medium and very fine sand Figure 7.
Figure 7 Sand grain size compositions at each Pangumbahan beach segment. Sampled at near high water mark HWM, no vegetation canopy NC
and under vegetation canopy UC.
Yonathan 2010, unpublished data pointed that the 300 m area at Pos 1 and some part of Pos 2 had width range of 40 – 60 m and slope of 2.8 – 6.5° in west
monsoon. The rest of beach profile information was mainly visual observation. In general, beach width in Pangumbahan was narrow at the edge and sligthly wider
at the center of the beach. Pos 2 and Pos 3 were the widest part Figure 8. Less steep beach slope was at Pos 1 and 2 whereas the steepest was at Pos 6. Creeper
10 20
30 40
50 60
70 80
90 100
c o
m p
o si
ti o
n
Clay Silt
Very fine sand fine sand
medium sand coarse sand
very coarse sand
plants were absent at Pos 1 and 2, small patches at Pos 3 and 4 and large extension at Pos 5 and Pos 6, see Appendix 3 for detail descriptions. Sea bottom substrate
around Pos 1 beach line was different with other beach segments. There were extensions of rocky substrate in front of this area which may reduce the
accessibility. Detail characteristic of each beach segment listed in Table 8 below.
Figure 8 Profile of Pangumbahan beach Landsat 7 ETM+ imagery. Source: http:edcsns17.cr.usgs.govEarthExplorer
Table 8 Characteristic of each beach segment in Pangumbahan
Parameter Pos 1
Pos 2 Pos 3
Pos 4 Pos 5
Pos 6
Dominant sand grain size :
UC medium
sand very fine
sand, fine sand
very fine sand, fine
sand very fine
sand, fine sand
very fine sand,
medium sand
very fine sand, fine
sand
NC medium
sand medium
sand medium
sand very fine
sand medium
sand medium
sand Vegetation:
Most common
species
Pandanus tectorius
Pandanus tectorius
, Calophyllum
inophyllum Pandanus
tectorius Pandanus
tectorius Pandanus
tectorius Pandanus
tectorius
Shade area m
220.72 448.62
150.5 141.95
127.69 374.77
∗ UC: Under vegetation canopy, NC: No vegetation canopy
22
4.1.1.1. Nesting fidelity
Abundance of green turtle landing at each beach segment was not evenly distributed. Pos 2 was the most abundance while Pos 6 was the least Table 9.
There were 15 out of 27 adult female green turtles observed landed at Pos 2, 14 of them successfully laid eggs. Pos 2 was the widest among others and less steep
while Pos 6 was narrow and had steepest slope. The sand substrate at both beach segments was dominated by very fine sand and fine sand grain. However, it was
found that the green turtle sand nest at Pos 2 was dominated by medium sand grain size n = 13 see Figure 9. Nuitja and Uchida 1983 concluded that green
turtle prefer to nest at beach with medium sized grains of sand. The most common species of beach vegetation at all beach segments, including Pos 2 and Pos 6, was
similar, i.e. Sea Pandan Pandanus tectorius. Nuitja 1992 reported that green turtle in Pangumbahan prefered to nest under P. tectorius. Difference between Pos
2 and Pos 6 was the extension of creeper plant Cyperus pedunculatus at Pos 6. The creeper plants might hamper green turtle in digging body pit and nest cavity.
In other words, Pos 2 was freer from burdens. The burdens also came from external factors such as local activity and light disturbance at exposed beach part
Pos 1, 5 and 6. Poaching was susceptible at this particular beach segment, with the most common case was occurred at Pos 5 and 6 outermost part of
conservation area. 23
Table 9 Green turtle abundance at Pangumbahan beach segments
Parameter Pos 1
Pos 2 Pos 3
Pos 4 Pos 5
Pos 6 Note
Green turtle abundance: - During field sampling
Nesting 4
14 2
2 -
- Not nesting
- 1
- 1
3 -
Total 4
15 2
3 3
- Secondary data Period: Sept 2006
Segara 2008, unpublished
data Nesting
20 66
41 13
Not nesting -
- -
- -
-
Total 20
66 41
13 -
-
Period: Jan 2007 Segara 2008,
unpublished data
Nesting 27
112 38
13 Not nesting
- -
- -
- -
Total 27
112 38
13
period Jan - May 2011 UPTD
Konservasi Penyu
Pangumbahan unpublished
data Nesting
46 138
90 74
43 2
Not nesting 33
90 78
76 54
37
Total 79
228 168
150 97
39
Figure 9 Sand grain size compositions of natural nests in Pangumbahan beach
4.1.1.2. Green turtle abundance
Female green turtles C. mydas visit Pangumbahan beach, Sukabumi almost through the year. The peak nesting season in the period of 2003-2005 and
2008-2011 was usually in October, with a variation occurred in 2009 and 2011
10 20
30 40
50 60
70 80
90 100
N A
T 1S
N A
T 2S
N A
T 3S
N A
T 4S
N A
T 5S
N A
T 6S
N A
T 7S
N A
T 8S
N A
T 9S
N A
T 1
… N
A T
1 …
N A
T 1
… N
A T
1 …
N A
T 1
… N
A T
1 …
N A
T 1
… N
A T
1 …
N A
T 1
… N
A T
1 …
N A
T 1
… N
A T
1 …
N A
T 1
… N
A T
1 …
N A
T 1
… N
A T
1 …
c o
m p
o si
ti o
n
Clay Silt
Very fine sand fine sand
medium sand coarse sand
very coarse sand