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Reproductive Biology of Pacific Oyster (Crassostrea gigas): A Decade after the Tsunami Disaster in Aceh, Indonesia

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The reproductive biology of pacific oysters (Crassostrea gigas) was studied in the coastal area of Banda Aceh City, Aceh Province, Indonesia. This study was conducted over six months from July to December, 2017. The samples were collected following the seasons. July to August represented the dry season, while September to October represented the transition season, and November to December had been within the rainy season. Surveys and observations were conducted at two locations, Tibang and Ulee Lheue, where samples were collected with a minimum of 150 samples per location per month. Data collection is done by the line transect method. The results of the analysis showed that the male oyster gonad first matured at a total length of 26.40 mm in Tibang and at the total length of 25.45 mm in Ulee Lheue. Furthermore, the female oyster gonad first matured at 20.46 mm of total length in Tibang and at a total length of 25.24 mm in Ulee Lheue. The range of oyster fecundity in Tibang is between 7,487,888-34,511,625 eggs/ind with an average fecundity reaching 17,360,821 eggs/ind, whereas the range of oyster fecundity in Ulee Lheue was between 9,237,258-40,575,863 eggs/ind with an average fecundity reaching 17,108,206 eggs/ind. The total number of the collected oyster samples was 1800 specimen, and all the samples were in the adult category. In addition to sex determination of the oysters into males and females, the oyster hermaphrodite sex is also found. The results of gonadal observation show that oysters are hermaphrodite synchronous (male and female gonads mature at the same time).
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JJBS
Volume 12, Number 5,December 2019
ISSN 1995-6673
Pages 553 - 560
Jordan Journal of Biological Sciences
Reproductive Biology of Pacific Oyster (Crassostrea gigas): A
Decade after the Tsunami Disaster in Aceh, Indonesia
Lili Kasmini1, Ternala A. Barus 1*, M. Ali Sarong2, Miswar Budi Mulya1 and Agung
Setia Batubara3
1Faculty of Mathemathics and Science, Universitas Sumatera Utara, Medan 20155; 2Faculty of Teacher Training and Education;
3Department of Aquaculture, Faculty of Marine and Fisheries, Universitas Syiah Kuala, Banda Aceh 23111, Indonesia.
Received January 6, 2019; Revised February 17, 2019; Accepted March 1, 2019
Abstract
The reproductive biology of pacific oysters (Crassostrea gigas) was studied in the coastal area of Banda Aceh City, Aceh
Province, Indonesia. This study was conducted over six months from July to December, 2017. The samples were collected
following the seasons. July to August represented the dry season, while September to October represented the transition
season, and November to December had been within the rainy season. Surveys and observations were conducted at two
locations, Tibang and Ulee Lheue, where samples were collected with a minimum of 150 samples per location per month.
Data collection is done by the line transect method. The results of the analysis showed that the male oyster gonad first
matured at a total length of 26.40 mm in Tibang and at the total length of 25.45 mm in Ulee Lheue. Furthermore, the female
oyster gonad first matured at 20.46 mm of total length in Tibang and at a total length of 25.24 mm in Ulee Lheue. The range
of oyster fecundity in Tibang is between 7,487,888-34,511,625 eggs/ind with an average fecundity reaching 17,360,821
eggs/ind, whereas the range of oyster fecundity in Ulee Lheue was between 9,237,258-40,575,863 eggs/ind with an average
fecundity reaching 17,108,206 eggs/ind. The total number of the collected oyster samples was 1800 specimen, and all the
samples were in the adult category. In addition to sex determination of the oysters into males and females, the oyster
hermaphrodite sex is also found. The results of gonadal observation show that oysters are hermaphrodite synchronous (male
and female gonads mature at the same time).
Keywords: Oyster, Crassostrea, Gonad, Reproductive, Fecundity, Hermaphrodite
* Corresponding author e-mail: ternala58@gmail.com.
1. Introduction
The tsunami in Aceh on December 26, 2004 occurred
more than a decade ago (14 years ago). The earthquake in
the Andaman Sea caused a tsunami in Aceh and claimed
130,000 human lives (Frankenberg et al., 2008). In
addition to causing human casualties, the tsunami also
damaged the coastal environment which previously served
as a habitat for both living flora and fauna organisms. It is
known that the height of the tsunami waves in Aceh
reached 30 m due to the 9.3SR earthquake which has
damaged the coastal environment (Suppasri et al., 2015).
Damage caused by tsunamis causes changes in coastal
geomorphology, topography, and soil cover (Bayas et al.,
2011). Based on previous research, the effects of tsunami
waves caused damage to corals in Aceh reaching up to 31
% in the low to medium category and 15 % in the heavily-
damaged category (Hagan et al., 2007). Furthermore, the
tsunami also damaged 32,004 hectares of mangrove forests
and coastal vegetation (Wibisono and Suryadiputra, 2006).
Tsunami waves that occurred in Aceh traveled up to a
radius of 3-4 km from the coastline (Hagan et al., 2007).
This caused mudflows from the seabed to cover the
surface of the land that was passed by the tsunami waves.
Tsunami mud residues allowed changes in the ecology of
the estuary area after the disaster occurred. One of the
organisms that live in the estuary area is oysters.
Oysters are organisms that are very sensitive to
environmental changes and can be indicators of pollution
in an area (Sarong et al., 2015; Astuti et al., 2016). Based
on previous studies that have been carried out in Aceh
Province, oysters which are most commonly found consist
of five species, included in two genera, namely the genus
Ostrea and the genus Crassostrea, consisting of C.
virginica, C. gigas, C. iridescens, C.angulata, and O.
edulis (Octavina et al., 2014). One of the mostly common
species found is C. gigas. The C. gigas are reported to
contribute to 80 % of the world's oyster trade and have
been cultivated in sixty-six countries (Keightley et al.,
2015).
Research on oysters in Aceh, includes the analysis of
heavy metal content in oysters (Sarong et al., 2015; Astuti
et al., 2016), community structure of meat oysters (Fadli et
al., 2012; Octavina et al., 2014), length-weight
relationships, and oyster condition factors (Octavina et al.,
2015; Kasmini et al., 2018). However, research on the
reproductive biology of oysters after the tsunami
phenomenon that struck in 2004 has not been carried out;
thus this study would be an important contribution to the
© 2019 Jordan Journal of Biological Sciences. All rights reserved - Volume 12, Number 5
554
development of Aceh oysters in the future, especially for
oyster conservation or cultivation.
2. Methods
2.1. Time and Location
The current research was carried out in the coastal area
of Banda Aceh City over the period of six months from
July to December, 2017. The samples were collected
following the seasons where July to August represented
the dry season, while September to October represented
the transition season, and November to December had
been within the rainy season.
2.2. Data Collection
The samples were taken from two research locations,
Tibang (5033’36.7” N, 95017’22.8” E; 5033’21.0” N,
95017’11.7” E; 5033’01.6” N, 95017’09.5” E) and Ulee
Lheue (5035’25.1” N, 95021’03.5” E; 5035’47.0” N,
95020’50.8” E; 5035’36.2” N, 95020’44.4” E). Each
location was divided into three research stations. The
collection of the samples was carried out using a purposive
sampling method, and a line transect method. Every
month, 150 samples were collected randomly from each
location consisting of fifty samples per station. The
samples that have been obtained were taken to the Marine
and Fisheries Faculty of the Marine Biology Laboratory
for further analysis. The oyster samples were then
identified based on Batista et al. (2008). The collected
samples were then separated from each other to facilitate
the measurements of length and weight. Length
measurements were performed using a digital caliper
(Precision Measuring Error = 0.01 mm), and weight was
taken for each individual using a digital scale (Pocket
Scale, MH-Series, Error = 0.01 g).
The preservation of the oyster's body was performed
using 10 % NBF (Neutral Buffer Formalin). The analyses
of oyster reproduction biology, including histology
examination, gonad maturity level, and fecundity were
carried out at the Pathology Laboratory, Brackishwater
Aquaculture Station (BBAP) Ujong Batee, Ministry of
Maritime Affairs and Fisheries, Indonesia.
2.3. Data Analysis
2.3.1. Gonad Maturity Level
The observation of the level of gonad maturity was
done visually according to Fabioux et al. (2005). This
observation aims at determining the maturity and seeing
the female and male reproductive organs, so that the size
of the oyster body when the gonad is mature can be
estimated. For this purpose, oysters with various sizes have
been distributed in several groups or classes based on body
size. Data on gonadal maturity are then correlated with the
length and weight of the oysters in each class. The
stomach of the oyster, the gonad shape, size, color and
texture were all observed in addition to the presence of
sperms or oocytes. Then the gonads were preserved and
examined histologically according to the procedure
described earlier (Roberts, 2012). The maturity level of the
gonads was also determined based on gonadal anatomy
and morphology, weighing of gonads, determination of
gonadosomatic index, and based on observations of
histological preparations according to Roberts (2012).
2.3.2 Gonadosomatic Index
The measurement of the gonadosomatic index (GSI)
was done by taking samples of the oysters that have been
weighed and measured in length, on which surgery has
been done to separate the gonads. They were finally
weighed using a digital scale. The GSI is calculated
according to Gaughan and Mitchell (2000) by the formula:
Where the GSI = gonadosomatic index (%), Wg = weight of the
gonad (g), and Wt = weight of the body (g).
2.3.3 Fecundity
Fecundity was measured with the formula by the
gravimetrics method based on Adenike (2013) as follows:
F =
Where F = fecundity/number of eggs (grains), Wg = weight of the
gonad (g), Wt = partial gonad weight (g), and Fs = number of eggs
in parts of gonad (grains).
2.3.4 Sex Dimorphism
The observation of sex dimorphism was done to
differentiate between the males and females of the oysters
morphologically or by physical appearance. For this
reason, the sampled oysters were observed visually
regarding their body color and shape. The oysters taken
were recorded morphologically, and the appearance of the
shape and color of the gonads were observed. They were
then grouped according to the same morphological
appearance and sex that were confirmed on the basis of the
histological examination under a microscope.
2.3.5 Histological Analysis and Reproductive Cycle
The sex and gonad maturity of each oyster was
determined based on a histological examination. The
procedures for making histology preparations using the
slice method were done according to Roberts (2012).
2.3.6 Sex Ratio
The sex ratio analysis aims at comparing the numbers
of male to the number of female individuals in a
population. The observation of the level of gonad maturity
and histology examination can help determine the sex of
the oysters, thus the ratio of the numbers of females and
males can be determined. Sex ratio is calculated by the
formula of Adenike (2013) as follows:
2.4. Statistical Analysis
The statistic data analysis was subjected to the chi-
square test followed by the Duncans multi-range test
applied for cheking the oyster sex ratio and gonadosomatic
index between the same and different locations using SPSS
ver. 22.0.
© 2019 Jordan Journal of Biological Sciences. All rights reserved - Volume 12, Number 5 555
3. Results
3.1. Sex Ratio and Gonadosomatic Index
Observations during the study showed that the size of
the oysters was between the total lengths of 20.40-136.22
mm with an average size of 46.29 mm concerning the
1800 samples at both locations of the study (Tibang and
Ulee Lheue). The results of male sex ratio (SR) analysis
show that the highest value was in October (31.33 %) at
the Tibang location and during September (36 %) at the
Ulee Lheue location. The the highest value of female SR
was found in December (75.33 %) at the Tibang location
and in August (66.67 %) at the Ulee Lheue location.
Furthermore, this study found oysters with hermaphrodite
genitals, and their highest SR values were found in
September (28.00 %) at Tibang and in October (28.67 %)
at Ulee Lheue locations (Tables 1 and 2).
The results show that the sex ratio (SR) studied at two
research sites (Tibang and Ulee Lheue) was dominated by
the female ratio with a mean value of 65.11 % in Tibang
area and 59.55 % at Ulee Lheue location. Male oysters
have an SR value of 20.22 % at Tibang location and 28.11
% at Ulee Lheue location. This study also detected
hermaphrodite oysters, where the average ratios were
14.67 % at Tibang location and 12.33 % at Ulee Lheue
location. Based on the average SR results, female and
hermaphroditic sexes at Tibang sites were higher than
those at Ulee Lheue, but lower than the mean values of
male SR.
Oyster SR values fluctuate every month, which is most
significantly seen through the genitals of hermaphrodites.
At the Tibang location, the value of hermaphrodite SR
increased in July to September and decreased from
October to December, whereas at the location of Ulee
Lheue the value of hermaphrodite SR continued to decline
in July to September and increased in October, but
decreased again between November to December (Figure
2a and b).
An analysis of gonadosomatic index (GSI) of female
oysters shows that the highest average value was found in
October (4.53 %) in Tibang and in November (4.80 %) in
Ulee Lheue. The highest mean male GSI score was found
in October (3.81 %) in Tibang and in November (5.11 %)
in Ulee Lheue. Furthermore, the highest mean
hermaphrodite GSI values were found in October in
Tibang (4.81 %) and in December (5.05 %) in Ulee Lheue
(Tables 5 and 6).
3.2. Gonad Maturity Level
In this study, male oysters first gained gonad at the
total length of 26.40 mm in Tibang and at 25.45 mm in
Ulee Lheue. This suggests that the mature size of male
oyster gonads does not significantly occur between the two
different sites. Furthermore, over the period of six months,
the study has found oysters with the highest gonadal
maturity in two locations occurring in August 96.77 %
(Tibang) and 92.31 % (Ulee Lheue) respectively (Table 3
and Figure 3).
Also, this study found female oysters’ gonads that first
matured at the size of 20.46 mm in Tibang and at 25.24
mm in Ulee Lheue. Furthermore, over the period of six
months, the study found oysters in the highest mature
gonad state in two locations (Tibang and Ulee Lheue)
occurring in August with the same value reaching up to
96 % (Table 4 and Figure 4).
3.3. Gonad Histology and Fecundity
The histologic results of the gonads indicate that
reproductive oysters are hermaphrodite (Figure 6).
Furthermore, the gonad of mature female oysters has a
maximum egg size of ± 50 μm which means that eggs
cannot be seen visually without the aid of tools. The size
of oysters with mature gonads in Tibang ranged from
20.46 to 94.30 mm with a fecundity range between
7,487,888 and 34,511,625 eggs/ind with an average of
fecundity of 17,360,821 eggs/ind.
The size of oysters with ripe gonads in Ulee Lheue
ranged from 25.24 to 110.87 mm with a fecundity range
between 9,237,258 and 40,575,863 eggs/ind and a
fecundity average of 17,108,206 eggs/ind. Regression
results showed a very close relationship (Tibang r = 0.95%
and Ulee Lheue r = 0.953%), in which the number of eggs
increases with the increase of oyster size (Figure 5).
4. Discussion
Based on sex identification, hermaphrodite oysters
were found in addition to male and female oysters at the
time of the study. The sex ratio (SR) during the study
found oysters dominated by the presence of females in two
locations, where the mean value was 65.11 % in the
Tibang area and 59.55 % in the Ulee Lheue location
(Table 5). The SR values of oysters fluctuate each month,
with the most significant fluctuation occurring in the
hermaphrodites. At the Tibang site, the hermaphrodite SR
value experienced an increase in July to September and
decreased in October to December, while at the Ulee
Lheue location, the SR hermaphrodite value continued to
decline in July to September, and experienced an increase
in October, but there was a further decline in November to
December (Figure 2).
The results of gonadal observation show that oysters
are hermaphrodite synchronous (male and female gonads
mature at the same time) (Figure 6). However, other
studies mention that in the reproductive cycle, oysters are
protandrous hermaphrodites whose life begins with the
male genitals turning into females several years later if the
environment is good and when sufficient nutrition is
available (Westphal et al., 2015). According to Dheilly et
al. (2012) oysters are generally protandrous
hermaphrodites, but there are several cases of synchronous
hermaphrodite oysters found because the gonads are labile.
Thus, there are changes in the physiological properties of
the oyster bodies in the study locations caused by
environmental factors. Changes in physiological properties
may occur due to tsunami disasters or other environmental
factors such as global warming or pollution. However, the
anthropogenic pressure of seawater can be a problem in
the development of aquatic organisms (Hamdani and
Soltani-Mazouni, 2011).
Analysis of the reproductive aspects of oysters showed
spawning peaks occurring in August (Table 3 and Table
4). This is due to the fact that both male and female oysters
are dominated by mature categories. In August, especially
in Banda Aceh, the peak of the dry season occurred, when
temperatures were relatively high and rain did not occur.
The dry season that occurs in August causes an increase in
© 2019 Jordan Journal of Biological Sciences. All rights reserved - Volume 12, Number 5
556
water salinity which then induces the spawning season of
oysters. This is consistent with the results of research
conducted by Dheilly et al. (2012) which states that oyster
spawning peaks occur in the summer because the
gametogenesis process occurs when the water temperature
increases. This finding was also strengthened by the results
of research conducted by Fabioux et al. (2005) which state
that the gametogenesis process in C. gigas develops during
summer with water temperatures being above 19 0C and
salinity>30 ppt. In other studies, it was also mentioned that
first-time oyster gonads develop in April and continue to
grow until they become matured in August when the initial
spawning process occurs and continues until September
(Li et al., 2000).
In this study, the male oyster gonad was first ripe at
26.40 mm in Tibang and at 25.45 mm in Ulee Lheue. This
shows that the size of first-time mature gonad of male
oysters did not differ significantly between the two
different locations. The gonads were first mature in female
oysters at 20.46 mm in Tibang and at 25.24 mm in Ulee
Lheue. According to Westphal et al. (2015), the genus
Crassostrea first reproduced (spawning) at a size of 20
mm. Thus all of the oysters collected from the Tibang and
Ulee Lheue estuaries are in the adult category.
Based on the results of the present study, it appears that
the ability of oyster recruitment is very high. This is
indicated by the high number of eggs (fecundity), at an
average of 17,360,821eggs/ind in Tibang and 17,108,206
eggs/ind in Ulee Lheue. The study found a positive
correlation (r) between the addition of length and egg
production in oysters with a value reaching 95 % in both
study locations, where the size of 110.87 mm (the highest
size of female genital oysters) can produce more than
40,000,000 eggs (Figure 5). If an organism has a high
recruitment ability, it can maintain the stability of its
population in nature (Bakun and Broad, 2003).
Furthermore, there is no dispensatory dynamics in oysters
similar to the phenomenon that often occurs in fish, where
the recruitment ability is low due to the difficulty of
finding a partner or allee effect (Myers et al., 1995). In
addition to that, the environment that often experiences
eutrophication has a positive influence on oysters for the
development of reproductive organs more often than the
environment which is poor in organic content (Fabioux et
al., 2005). It is known that oyster reproductive activity
(recruitment) is done by random removing of eggs and
sperm into the waters when stimuli for spawning are
detected (Westphal et al., 2015).
The maximum size of C. gigas eggs with mature
gonads during the study only reached ± 50 μm and that is
why the eggs could not be seen visually. This is consistent
with the results of research conducted by Lango-Reynoso
et al. (2000) stating that the size of C. gigas eggs matured
in gonads ranging from 31 to 60 μm. Furthermore, in other
studies, it was stated that the maximum size of C. gigas
eggs in mature conditions reached 48.7 µm (Li et al.,
2000).
Thus, the size of the oyster is very important as an
indicator of egg-laying productivity. The measurement
shows reproductive performance and its association with
the process of recruiting new offspring of oysters. In male
oysters the number is much less than in female oysters, so
the ability of oyster regeneration will be very fast due to
the fact that the role of female oysters are very significant
because of the feature of egg production. Oysters with
mature gonads can be found every month, which means
that oysters can spawn throughout the year.
Table 1. Sex ratio (SR) and gonadosomatic index (GSI) C. gigas at Tibang
Month Ind Male Oyster Female Oyster Hermaprodite
SR (%)
GSI (%)
SR (%)
GSI (%)
SR (%)
GSI (%)
July 150 21.33 0.53-8.51
2.73±1.45 68.67 0.08-14.32
2.57±1.83 10.00 0.40-6.89
3.24±1.93
August 150 20.67 1.22-8.60
3.71±1.62 66.67 0.50-17.67
3.85±2.31 12.67 0.54-7.87
3.44±1.80
September 150 14.67 0.82-5.93
2.82±1.37 57.33 1.08-12.27
3.78±1.83 28.00 0.88-11.85
3.80±1.85
October 150 31.33 0.41-11.57
3.81±2.77 48.00 0.31-11.97
4.53±2.46 20.67 0.80-18.60
4.81±4.26
November 150 14.67 1.43-7.33
3.81±1.64 74.67 0.48-11.25
4.18±1.98 10.67 0.75-6.88
3.89±1.75
December 150 18.67 0.39-6.38
3.25±1.70 75.33 0.58-9.91
3.53±1.98 6.00 0.75-5.17
2.84±1.73
© 2019 Jordan Journal of Biological Sciences. All rights reserved - Volume 12, Number 5 557
Table 2. Sex ratio (SR) and gonadosomatic index (GSI) C. gigas at Ulee Lheue
Month Ind Male Oyster Female Oyster Hermaprodite
SR (%) GSI (%) SR (%) GSI (%) SR (%) GSI (%)
July 150 32.67 0.04-6.97
0.78±1.40 57.33 0.11-5.58
1.47±1.37 10.00 0.35-4.81
1.72±1.45
August 150 26 0.04-6.26
1.85±1.33 66.67 0.01-12.17
2.64±2.13 7.33 0.57-6.99
3.50±1.76
September 150 36 0.77-13.85
4.06±3.05 60 0.30-16.73
3.61±2.66 4 0.39-2.97
1.77±1.04
October 150 25.33 0.42-12.36
3.25±2.23 46.00 0.60-10.26
3.87±1.92 28.67 0.77-10.24
3.81±2.03
November 150 20.67 1.02-19.06
5.11±3.35 63.33 0.34-16.56
4.80±2.44 16.00 0.35-9.54
4.54±2.33
December 150 28.00 0.95-8.10
3.00±1.56 64.00 0.05-16.56
3.56±2.42 8.00 1.58-9.55
5.05±2.62
Table 3. Gonad maturity level of male oyster at Tibang and Ulee Lheue
Month
Tibang Ulee Lheue
Ind
Gonad maturity level (%)
Ind
Gonad maturity level (%)
I II III IV V I II III IV V
July 32 3.13 0.00 3.13 90.63 3.13 49 73.47 6.12 4.08 16.33 0.00
August 31 0.00 0.00 3.23 96.77 0.00 39 7.69 0.00 0.00 92.31 0.00
September 22 0.00 50.00 27.27 18.18 4.55 54 20.37 59.26 9.26 9.26 1.85
October 47 0.00 14.89 14.89 44.68 25.53 38 0.00 15.79 21.05 28.95 34.21
November 22 0.00 9.09 63.64 27.27 0.00 31 3.23 16.13 35.48 45.16 0.00
December 28 0.00 0.00 53.57 42.86 3.57 42 0.00 4.76 21.43 73.81 0.00
Table 4. Gonad maturity level of female oyster at Tibang and Ulee Lheue
Month
Tibang Ulee Lheue
Ind Gonad maturity level (%) Ind Gonad maturity level (%)
I
II
III
IV
V
I
II
III
IV
V
July 103 2.91 2.91 9.71 77.67 6.80 86 5.81 5.81 33.72 48.84 5.81
August 100 0.00 0.00 2.00 96.00 2.00 100 3.00 0.00 1.00 96.00 0.00
September 86 3.49 13.95 24.42 24.42 33.72 90 18.89 18.89 23.33 25.56 13.33
October 72 0.00 30.56 20.83 33.33 15.28 69 1.45 17.39 27.54 47.83 5.80
November 112 0.00 0.89 27.68 71.43 0.00 95 0.00 16.84 32.63 50.53 0.00
December 113 0.00 2.65 35.40 61.95 0.00 96 3.13 8.33 33.33 55.21 0.00
Table 5. The statistical analysis of SR and GSI according to each sampling location. The values in the same row followed by different
superscripts are significantly different (P<0.05).
Location Variable Male Female Hermaprodite
Tibang
SR (%) 14.67-31.33
20.22±6.15a
48-75.33
65.11±10.62b
6-28
14.67±8.13a
GSI (%) 2.73-3.81
3.35±0.49a
2.57-4.53
3.74±0.67a
2.84-4.81
3.67±0.68a
Ulee Lheue
SR (%) 20.67-36
28.11±5.49b
46-66.67
59.55±7.39c
4-28.67
12.33±8.93a
GSI (%)
0.78-5.11
3.00±1.54a
1.47-4.8
3.32±1.14a
1.72-5.05
3.39±1.39a
Table 6. The comparative analysis of SR and GSI at the Tibang and Ulee Lheue locations. The values in the same row followed by different
superscripts are significantly different (P<0.05).
Sex SR (%) GSI (%)
Tibang Ulee Lheue Tibang Ulee Lheue
Male 14.67-31.33
20.22±6.15a
20.67-36
28.11±5.49a
2.73-3.81
3.35±0.49a
0.78-5.11
3.00±1.54a
Female 48-75.33
65.11±10.62a
46-66.67
59.55±7.39a
2.57-4.53
3.74±0.67a
1.47-4.8
3.32±1.14a
Hermaprodite 6-28
14.67±8.13a
4-28.67
12.33±8.93a
2.84-4.81
3.67±0.68a
1.72-5.05
3.39±1.39a
© 2019 Jordan Journal of Biological Sciences. All rights reserved - Volume 12, Number 5
558
Figure 1. Research map. The study was conducted in Ulee Lheue and Tibang, each location consisted of 3 sampling points.
Month
DesemberNovemberOctoberSep temberAugustJuly
Sex Ratio (%)
120
100
80
60
40
20
0
Female
Hermaprodite
Male
Month
DesemberNovemberOctoberSep temberAugustJuly
Sex Ratio (%)
120
100
80
60
40
20
0
Female
Hermaprodite
Male
Figure 2. Sex ratio ratio (SR) oyster Crassostrea gigas, where a) Tibang location and b) the location of Ulee Lheue.
Month
Desembe r
November
October
September
August
July
Percent
120
100
80
60
40
20
0
TKG V
TKG IV
TKG III
TKG II
TKG I
Month
Desember
November
October
September
August
July
Percent
120
100
80
60
40
20
0
TKG V
TKG IV
TKG III
TKG II
TKG I
Figure 3. Percentage of mature male oyster gonad maturity levels (TKG) in a six-month study, where a) loaction of Tibang and b) Ulee
Lheue.
a)
b)
a)
b)
© 2019 Jordan Journal of Biological Sciences. All rights reserved - Volume 12, Number 5 559
Month
Desember
November
October
September
August
July
Percent
120
100
80
60
40
20
0
TKG V
TKG IV
TKG III
TKG II
TKG I
Month
Desember
November
October
September
August
July
Percent
120
100
80
60
40
20
0
TKG V
TKG IV
TKG III
TKG II
TKG I
Figure 4. Percentage of mature female oyster gonad maturity levels (TKG) for 6 months of study, where a) loaction of Tibang and b) Ulee
Lheue.
Figure 5. Regression of total length (mm) and oyster fecundity (egg/ind), where a) is Tibang and b) Ulee Lheue
Figure 6. Histological appearance of oyster gonads, a) male, b) female, c) hermaphroditic.
5. Conclusion
The male oyster gonad first matured at 26.40 mm in
Tibang and at 25.45 mm in Ulee Lheue. Furthermore, the
female oyster gonad first matured at 20.46 mm in Tibang
and at 25.24 mm in Ulee Lheue. The range of oyster
fecundity in Tibang Village is between 7,487,888 and
34,511,625ggs/ind with an average fecundity reaching
17,360,821 eggs/ind; the range of oyster fecundity in Ulee
Lheue was between 9,237,258 and 40,575,863eggs/ind
with and average fecundity reaching 17,108,206 eggs/ind.
a)
b)
© 2019 Jordan Journal of Biological Sciences. All rights reserved - Volume 12, Number 5
560
In addition to the male and female oysters, oysters of the
hermaphrodite sex were also found.
Conflict of interest
The authors declare that there is no conflict of interest.
Acknowledgement
This study was supported by Kemenristek Dikti
through “Penelitian Disertasi Doktor 2018” scheme.
Therefore, the authors thank Kemenristek Dikti for
supporting this study. The authors would like also to
express appreciation for Mr. Muchlis, Ms. Nur Masyitah,
and Ms. Roza Noviana for their assistance during field and
laboratory works.
Author contribution
L.K.: the author is responsible for data collection,
sample maintaining, data analysis, and manuscript
drafting; T.A.B.: the author is responsible for developing
of the study design, supervision, data validation, review
and editing of the draft manuscript; M.A.S.: developing of
the study design, supervision, data validation, review and
editing the draft manuscript; M.B.M.: research
supervision, data validation, review and editing of the draft
manuscript; A.S.B.: data collection, sample maintaining,
data analysis and validation. All authors read and approved
the final manuscript.
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