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Relationship between the Carapace Width and Body Weight
Increments and the Confirmation of Stage 1 Ovary after the Molting of Immature Orange Mud Crabs, Scylla olivacea
(Herbst, 1796), in Captivity
Journal: Songklanakarin Journal of Science and Technology
Manuscript ID SJST-2017-0375.R1
Manuscript Type: Original Article
Date Submitted by the Author: 16-Mar-2018
Complete List of Authors: Adnan, Amin-Safwan; Universiti Malaysia Terengganu, Institute of Tropical Aquaculture Harman, Muhd-Farouk; Universiti Malaysia Terengganu, Institute of Tropical Aquaculture; Impact Assessment Research Division, Fisheries Research Institute Batu Maung, Department of Fisheries Ismail, Nurul-Hasyima; Universiti Malaysia Terengganu, Institute of Tropical Aquaculture Mahsol, Hairul Hafiz; Universiti Malaysia Terengganu, Institute of Tropical
Aquaculture; Universiti Malaysia Sabah, Institute of Tropical Biology and Conservation Ikhwanuddin, Mhd; Universiti Malaysia Terengganu, Institute of Tropical Aquaculture; Universiti Malaysia Terengganu, School of Fisheries and Aquaculture Sciences
Keyword: Molting, <i>S. olivacea</i>, carapace width, body weight, maturation
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Relationship between the Carapace Width and Body Weight Increments and the
Confirmation of Stage 1 Ovary after the Molting of Immature Orange Mud Crabs,
Scylla olivacea (Herbst, 1796), in Captivity
Adnan Amin-Safwan1, Harman Muhd-Farouk1, 2*, Nurul Hasyima-Ismail1, Hairul Hafiz
Mahsol1,3, and Mhd Ikhwanuddin1*
1Institute of Tropical Aquaculture, Universiti Malaysia Terengganu, 21030 Kuala Nerus,
Terengganu, Malaysia
2Impact Assessment Research Division, Fisheries Research Institute Batu Maung,
Department of Fisheries, 11960 Batu Maung, Pulau Pinang, Malaysia
3Institute for Tropical Biology and Conservation, Universiti Malaysia Sabah, Jalan UMS,
88400 Kota Kinabalu, Sabah, Malaysia
*Corresponding Authors: Mhd Ikhwanuddin, Email: [email protected] and
Harman Muhd-Farouk, Email: [email protected]
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Relationship between the Carapace Width and Body Weight Increments and the 1
Confirmation of Stage 1 Ovary after the Molting of Immature Orange Mud Crabs, Scylla 2
olivacea (Herbst, 1796), in Captivity 3
4
Abstract 5
This study describes the relationships between the carapace width (CW) and body weight 6
(BW) increment and the confirmation of Stage 1 ovary after the molting of immature orange 7
mud crabs, Scylla olivacea, in captivity. Morphological coloration and histological assessments 8
were done on 165 immature female S. olivacea. Healthy crabs were sampled from the Setiu 9
Wetlands in the coastal waters of Terengganu on the Malaysian Peninsula from July to 10
September 2015. Thirty crabs were sacrificed for a preliminary study as a standard (control) in 11
which the gonads (if available) were dissected for histological study. The remaining crabs 12
(n=135) were selected for subsequent analysis (limb autotomy). Compared to the controls, the 13
molted crabs generally did not produce any difference in the stage of the ovaries (remaining in 14
Stage 1) but were observed to have larger oocytes. This demonstrated that the limb autotomy 15
technique may activate hormone regulation, thus triggering vitellogenesis in the mud crab. There 16
were also positive correlations between CW and BW (p=0.001; p<0.01) and significant 17
differences through regression analysis (ρ=0.002; ρ<0.01) with the equation y=2.61x + 6.27 18
(R2=0.069). These results can be useful for developing baseline data for further crab 19
management in Malaysia. 20
21
Keywords: Molting, S. olivacea, carapace width, body weight, maturation 22
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23
1.0 Introduction 24
Mud crabs (Scylla olivacea) have recently become the most important and valuable 25
fisheries species in Malaysia along with two other species, S. tranquebarica and S. 26
paramamosain (Azra & Ikhwanuddin, 2016; Ikhwanuddin, Bachok, Hilmi, Azmie, & Zakaria, 27
2010a; Ikhwanuddin, Bachok, Mohd-Faizal, Azmie, & Abol-Munafi, 2010b; Ikhwanuddin, 28
Azmie, Juariah, Zakaria, & Ambak, 2011). They are widely distributed around the South China 29
Sea and extend into the Indian Ocean and the western Pacific (Ikhwanuddin et al., 2011; Keenan, 30
Davie, & Mann, 1998). The demand for this species has increased recently due to its quality, 31
including high meat yield (Rattanachote & Dangwatanakul, 1992), large size (Ikhwanuddin, Nur-32
Atika, Abol-Munafi, & Muhd-Farouk, 2014) and rapid growth during culture (Millamena & 33
Quinitio, 1999). Recently, the production of mud crabs has become an important import 34
commodity (Ikhwanuddin et al., 2014), leading to many great opportunities in crab farming 35
(Begum, Shah, Mamun, & Alam, 2009), as they are in high demand for all size classes, including 36
mature females for premium market activities as well as soft-shell production for food materials 37
(Hungria, Tavares, Pereira, Silva, & Ostrensky, 2017; Marichamy & Rajapackiam, 2001). The 38
high demand in local markets for large-size crabs, together with the local fisheries practice of 39
selling all sizes of mud crabs (Waiho, Fazhan, & Ikhwanuddin, 2016), prompted the present 40
study of the size and carapace width increments of mud crabs. 41
A morphometric analysis based on Cadrin (2000) provides a powerful complement to 42
genetic and environmental stock identification approaches and weight-width relationships in 43
populations and is important for estimating the population size of a stock for exploitation 44
purposes (Oluwatoyin, Akintade, Edwin, & Victor, 2013). According to Atar and Secer (2003), 45
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the weight increment and length-width ratio are widely used in a given geographic region for 46
identifying the growth and formation of a species. Many investigations based on Oluwatoyin et 47
al. (2013) have studied the length-weight relationships of fin-fishes, but such information about 48
portunid species is still scarce (Sukumaran & Neelakantan, 1997). The length-width relationship 49
is regarded as the most suitable measurement for evaluating fish (Dulcic & Kraljevic, 1996; 50
Jones, Petrell, & Pauly, 1999; Petrakis & Stergiou, 1995; Stickney, 1972) and crustacean 51
(Ikhwanuddin et al., 2010a; Sukumaran & Neelakantan, 1997; Tabash, 2001; Villasmil, 52
Mendoza, & Ferrer, 1997) populations. Moreover, there is little information on carapace width 53
and body weight increments and estimation equations after the crabs have molted. There has also 54
been disagreement about the ovarian maturation stage changes after each molt (International 55
Workshop on Portunid Crabs Aquaculture and Sustainable Fisheries 2016, Universiti Malaysia 56
Terengganu, Terengganu, Malaysia). 57
In this study, the relationships between carapace width and body weight were analyzed 58
and presented. We aimed to determine the sizes of and relationships between the carapace width 59
and body weight increments after immature female mud crabs, S. olivacea, molted. In addition, 60
the ovarian maturation stages after the immature crabs molted were also determined to confirm a 61
baseline as a starting point for future research. 62
63
2 Methodology 64
2.1 Sampling 65
A total of 165 immature female S. olivacea with carapace widths (CW) less than 9.06 cm 66
(Ikhwanuddin et al., 2010a, b) were sampled from Setiu Wetlands Mangrove Forest, 67
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Terengganu, Malaysia (5°31′23.1″N 102°55′56.1″E) from July to September 2015. The crabs 68
were transported alive to the Institute of Tropical Aquaculture Marine Hatchery, where their 69
morphological characteristics were determined following the methods of Keenan et al. (1998). 70
The CW and BW of each crab were measured using a six-inch liquid crystal display (LCD) 71
digital Vernier caliper (accuracy, 0.01 cm; Kingsmart brand, Hong Kong) and a digital electronic 72
balance (accuracy: 0.01 g; Shimadzu model, Japan) and were labeled with a cable tie tag (Nylon, 73
3 x 150 mm). The CW distance was measured between the 9th
antero-lateral spines of the mud 74
crabs’ carapaces. 75
76
2.2 Induced molting in immature crabs 77
Thirty immature crabs were randomly chosen as a control, while the remaining 135 crabs 78
were used for subsequent analyses. To induce molting, limb autotomy was applied (Amin-79
Safwan, Muhd-Farouk, Nadirah, & Ikhwanuddin, 2016; Nadiah, Ikhwanuddin, & Abol-Munafi, 80
2012) to 135 immature crabs by cutting off the chelipeds and walking legs while leaving the 81
pleopods (swimming legs) for the crab’s movement. The autotomized crabs were then cultured in 82
fiberglass tanks (320 cm x 138 cm x 60 cm) with an ambient salinity (28-32 ppt), temperature 83
maintained (27-29°C) using a heater, moderate aeration, ambient light intensity and 100% water 84
exchange every two days. The crabs were fed with chopped yellowstripe scad, Selaroides 85
leptolepis, at 10% of their body weight twice daily (at 0900 and 1700 h) for observation of the 86
molting event. The culture period ended after all the autotomized crabs had successfully molted. 87
88
2.3 Experimental design 89
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Thirty immature crabs were randomly chosen and dissected to be used for the control 90
data for external morphology and histological assessment. A total of 135 immature crabs were 91
administered the limb autotomy technique to induce molting. Once the crabs molted and their 92
carapace had fully hardened (on average in 7 days), their BW and CW were measured again to 93
determine the increment size. Next, all the molted crabs with fully hardened carapaces were 94
dissected to determine the ovarian maturation stages (based on coloration), and a small portion of 95
the ovarian lobes was fixed in Davidson’s solution (24 h) for histological assessment and 96
confirmation of the ovary stage. Davidson’s solution was chosen as the fixative in the present 97
study as it is the most suitable medium for crab tissues (Muhd-Farouk, Amin-Safwan, & 98
Ikhwanuddin, 2016a). 99
100
2.4 Histological assessments 101
The histological study was based on the standard histological procedure following Muhd-102
Farouk, Jasmani, and Ikhwanuddin (2016b). Tissue processing of a small portion of ovarian 103
lobes that had been fixed in Davidson’s solution (24 h) and continued with 70% alcohol 104
(overnight) was done in the Automatic Tissue Processor for 18 ± 1 h at 60°C to infiltrate the 105
fixed tissue samples. After the processing and hydration of the tissue was complete, wax 106
impregnation was performed by embedding it in a paraffin wax to form a solid block for easier 107
handling. The solid block was then sectioned into 5 µm sections using a rotating microtome 108
(Leica RM2135). The sections were placed on the paraffin section in a water bath (temperature 109
maintained at 40-45°C) to allow them to expand. After the sections were fully expanded, a 110
microscope slide was held at an angle and slid under one or two well-formed tissue sections (the 111
fishing step). After the fishing step was complete, the microscopic slides were dried on a hot 112
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plate (40°C) overnight. The samples were then stained with modified haematoxylin-eosin 113
(H&E). The diameters of 100 oocytes from each crab were measured using an Advanced 114
Research Microscope (Nikon Eclipse 80i, Japan) together with NIS-Elements D 2.30 software. 115
116
2.5 Data analysis 117
The CW and BW increment sizes were measured and recorded. The external morphology 118
of the ovaries was photographically recorded, and the oocyte structures and diameter sizes were 119
histologically measured and recorded. The collected data were analyzed using statistical 120
correlation (to determine the strength of a relationship with available statistical data) and 121
regression analysis (for estimating the relationships among the variables) through the Statistical 122
Package for the Social Sciences (SPSS) software (version 22.0 for Windows; SPSS Inc., 123
Armonk, NY: IBM Corp.). The data are shown as the means ± standard deviations (SD). 124
125
3 Results 126
3.1 External morphology and histological assessment 127
Morphologically, all 30 immature female crabs dissected for control data were in Stage 1 128
ovary (Figure 1a). The ovary was very small, thin and very hard to differentiate from the 129
digestive gland. Ovaries were seen as a strand- and ribbon-like tissue structure. However, the 130
result for 135 crabs that underwent induced molting by limb autotomy techniques showed 131
development after the crab had molted, but remained in Stage 1 ovary with increased ovary 132
volume (Figure 1b). 133
Table 1 shows the mean oocyte diameter for the control and treatment (autotomized crab) 134
of S. olivacea in this study. Regarding the histological assessment, the mean oocyte diameter for 135
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the control crabs was 25.67 ± 4.38 µm, which was referred to as Stage 1 ovary (Figure 1c). The 136
mean oocyte diameter after the crabs molted showed an increment in oocyte sizes, but still 137
maintained a Stage 1 ovary with 34.76 ± 12.13 µm. The oocyte, follicle cells, nucleus and 138
oogonia were still present (Figure 1d). 139
140
3.2 Size of Carapace Width and Body Weight Increments 141
Table 2 shows the mean, standard deviation, and highest and lowest recorded CW and 142
BW increments of S. olivacea in this study. Figures 2 and 3 show the frequency of CW and BW 143
increments in S. olivacea. On average, the CW and BW increments were 0.816 ± 0.27 cm and 144
8.395 ± 2.72 g, respectively. 145
146
3.3 Correlation and Regression Analyses 147
Table 3 shows the correlation analysis in this study. There was a positive correlation 148
between CW and BW (ρ=0.001; ρ<0.01). As CW increased, BW also significantly increased in 149
S. olivacea. The regression analysis (Table 4) showed a significant difference (ρ=0.002; ρ<0.01), 150
with y=2.61x + 6.27 (R2=0.069) (Figure 4) between CW and BW in S. olivacea. 151
152
4 Discussion 153
Crustaceans undergo molting (ecdysis) numerous times throughout their lives (Ryer, 154
Montfrans, & Moody, 1997). The molting event, a complex, energy-demanding process, is a 155
difficult and stressful time in the life of crustaceans and is the most vulnerable time for 156
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cannibalization. A crab molts 20 to 25 times during its life (Gaude & Anderson, 2011), normally 157
for growth, ovarian maturation, mating, and stressful conditions, and molting is also influenced 158
by several environmental factors. On the basis of previous studies of spiny crab species by Atar 159
and Secer (2003) and Oluwatoyin et al. (2013), the length measurement of crabs is said to be 160
difficult, and during attempts to measure them, either the extremities of the crab can be broken or 161
the investigator can be injured by the crab. In addition, determinations of the size of the 162
increment after crabs molted in the wild are still scarce. Only by rearing the crabs in captivity 163
can the size of the increments be confirmed. It is therefore convenient to estimate and convert 164
into width (length) when only the weight is known or vice versa (Atar & Secer, 2003; 165
Czerniejewski & Wawrzyniak, 2006; Josileen, 2011; Oluwatoyin et al., 2013). These 166
relationships are often used to calculate the standing stock biomass, condition indices, 167
ontogenetic changes and several aspects of fish or crustacean population dynamics (Atar & 168
Secer, 2003; Oluwatoyin et al., 2013). Moreover, according to Sukumaran and Neelakantan 169
(1997), body weight, total length, carapace width and carapace length are the most frequently 170
used dimensions, especially in the field of crustacean studies. 171
A previous study by Smith (1990) on the blue crab, Callinectes sapidus, found that this 172
species can regenerate almost 90% of its normal limb length in the first molt and nearly 100% in 173
the second molt after the loss of a single cheliped. Josileen and Menon (2005) stated that blue 174
swimming crabs, Portunus pelagicus, were able to regenerate 90% of their normal size in the 175
next molt, supporting a previous study by Smith (1990), and this does not affect the molt 176
increment or the molt interval. Our study recorded a similar result, with 85% regeneration of 177
their normal size; however, the chelipeds’ size became smaller than before. This may due to the 178
multiple limb loss from the limb autotomy technique used in our study, which affected the rate of 179
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the chelipeds’ growth. Bennett (1973) and Kuris and Mager (1975) noted that the molt increment 180
decreases proportionally with the increasing numbers of limbs lost, thus supporting our 181
assessment of the cause of the decreasing size of mud crab chelipeds. 182
Our study showed that as the crabs molted, both the carapace width (CW) and body 183
weight (BW) increased. These results were supported by a strong positive correlation (ρ=0.001; 184
ρ<0.01) between CW and BW. The regression analysis showed a significant result (ρ=0.002; 185
ρ<0.01) with y=2.61x + 6.27. However, our value of R2
=0.069 showed a very weak coefficient 186
of determination compared to previous studies (Atar & Secer, 2003; Oluwatoyin et al., 2013; 187
Sudha Devi & Smija, 2015) on crabs. On average, the CW increment was 0.816 ± 0.27 cm, with 188
the highest and the lowest increments recorded of 1.54 cm and 0.30 cm, respectively. 189
Meanwhile, the average BW increment was 8.395 ± 2.72 g, with the highest and lowest 190
increments recorded at 19.0 g and 3.2 g, respectively. Our findings proved that as female crabs 191
molted, their carapace size, body weight and ovary increased in size, similar to the results 192
recorded by Josileen and Menon (2005) for P. pelagicus. However, their study did not include 193
ovarian development. By focusing on the CW-BW relationship, the equation obtained can be 194
used to determine the size of the in situ population in an area and thus can predict the population 195
there. 196
Concerning ovarian maturation, four ovarian stages have been recorded on the basis of 197
recent studies (Amin-Safwan et al., 2016; Azmie, Azra, Noordiyana, Abol-Munafi, & 198
Ikhwanuddin, 2017; Ikhwanuddin et al., 2014; Muhd-Farouk et al., 2016b) on the same species, 199
S. olivacea. However, no study has been done on the ovarian maturation stages after immature 200
crabs molted, and the biological information about mud crabs is scarce. There is also confusion 201
among crab breeders and researchers about the ovarian maturation after immature crabs molted 202
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(International Workshop on Portunid Crabs Aquaculture and Sustainable Fisheries 2016, 203
Universiti Malaysia Terengganu, Terengganu, Malaysia). Some of them suggested that the crabs 204
have advanced to the next stage, while others suggested that the cycle of ovarian maturation 205
started again (Personal communications: Amirul, 2016; Aziz, 2015). Therefore, there is an urgent 206
need for the present study focusing on the ovarian stage after immature crabs have molted, which 207
we claim is the first report on immature crab ovarian development after a molting event occurs. 208
Our study recorded that ovarian development was present as the crabs molted; however, 209
they remained in Stage 1 ovary. The external morphology showed that the molted crabs’ ovaries 210
were much more developed compared to the control ovary, which was very small, thin and very 211
difficult to differentiate from the digestive gland. Moreover, the ovaries were seen as strand- and 212
ribbon-like tissue structures both before and after the molting event. To confirm the ovarian 213
maturation stages, a histological assessment was done to obtain more accurate results (Madlen, 214
Khadiga, & Montaser, 2012). From a histological perspective, the ovarian maturation of S. 215
olivacea after the molting event was confirmed as Stage 1 ovary with a mean oocyte diameter of 216
34.76 ± 12.13 µm. The oocyte, follicle cells, nucleus and oogonia were present. Compared to the 217
control crabs with a mean oocyte diameter of 25.67 ± 4.38 µm, the oocyte diameter after the 218
molting event showed an increase in size, thus demonstrating the occurrence of ovarian 219
development after crab molting. The ovarian development could have resulted from the limb 220
autotomy technique, which leads to the activation of hormone regulation and vitellogenesis. 221
However, a further in-depth study is needed as our understanding of vitellogenesis, particularly 222
in the mud crab, is still limited. Moreover, a better understanding of hormone regulation after 223
limb autotomy is performed is crucial as this technique is currently one of the favorite practices 224
in soft-shell production. Nevertheless, our result shows that the ovary remained in Stage 1, and 225
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this information can be used as a new finding about mud crab biology. In addition, this 226
information can become a new guideline and an indicator for future research perspectives. 227
Temperature and the quality and quantity of food are the most important environmental 228
factors that can affect molting and growth in crustaceans (Josileen & Menon, 2005). In this 229
study, these two parameters have been maintained as well as possible. The temperature was 230
maintained in the range of 27-29°C throughout the study period, similar to the temperature range 231
of a previous study done by Josileen and Nemon (2005) on P. pelagicus, while feeding 10% of 232
the body weight twice daily (0900 and 1700 h). Compared to these parameters, salinity and light 233
intensity have little effect on the molting event and inter-molt period of S. olivacea in captivity. 234
These findings were supported by Hartnoll (1982) and Josileen and Menon (2005), who 235
concluded that there was no significant change in the inter-molt period with regard to salinity in 236
several species of crustaceans. 237
It is recommended that further studies are needed on CW-BW as the equation in this 238
study showed a weak coefficient of determination. It is also suggested that male crabs and a 239
higher number of samples be included in future studies. In addition, we also suggest that further 240
studies focus more on limb autotomy, as we believe that this technique could trigger some 241
hormones that activate vitellogenesis and growth in crustaceans. Further study is thus crucial to 242
fully understand hormone regulation and the vitellogenesis mechanism after limb autotomy is 243
introduced. With a complete understanding of the CW-BW relationship and the ovarian 244
maturation stages, the data obtained can be used as an important baseline for future mud crab 245
resource management in that particular area. 246
247
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5 Conclusion 248
This study showed that there was a positive and strong correlation between CW and BW 249
(ρ=0.001; ρ<0.01) and that the mean CW and BW increments of female S. olivacea were 0.816 ± 250
0.27 cm and 8.395 ± 2.72 g. The regression analysis showed a significant difference (ρ=0.002; 251
ρ<0.01) with an estimation equation of y=2.61x + 6.27 for BW and CW. However, the 252
coefficient of determination (R2
=0.069) showed a very weak estimation value in this study. We 253
recommend that further studies are needed to obtain a strong coefficient of determination, as the 254
R2 value is important to ascertain how strong a linear relationship is between the variables 255
determining the population in a particular area. Meanwhile, both the external morphological 256
assessment and the histology have shown that after immature crabs molted, the ovaries remained 257
in Stage 1. However, this study may have demonstrated that vitellogenesis was activated by 258
hormone regulation during the performance of limb autotomy and thus can be used as the 259
baseline for future studies. 260
261
Acknowledgements 262
This research was funded by the Ministry of Higher Education under the Niche Research Grant 263
Scheme (NRGS) Vote No. 53131. Our greatest appreciation goes to the Institute of Tropical 264
Aquaculture, Universiti Malaysia Terengganu and to all the people who were directly or 265
indirectly involved during this study. We thank Mohamad N Azra and Mardhiyyah Mohd Pauzi 266
for providing valuable comments and an English revision of an earlier draft of the manuscript. 267
268
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Decapoda-Brachyura-Portunidae.pdf 339
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Fisheries Science Journal, 14, 231-238. Retrieved from 348
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serrata fed various broodstock diets. Proceedings of the International Scientific Forum of 351
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Muhd-Farouk, H., Amin-Safwan, A., & Ikhwanuddin, M. (2016a). Effect of different fixatives 353
on different organs of orange mud crab, Scylla olivacea (Herbst, 1796). International 354
Conference on Marine Science and Aquaculture, Kota Kinabalu, Sabah, Malaysia, March 355
23-24, 2016. 356
Muhd-Farouk, H., Jasmani, S., & Ikhwanuddin. M. (2016b). Effect of vertebrate steroid 357
hormones on the ovarian maturation stages of orange mud crab, Scylla olivacea (Herbst, 358
1796). Aquaculture, 451, 78–86. doi:10.1016/j.aquaculture.2015.08.038 359
Nadiah, W. N., Ikhwanuddin, M., & Abol-Munafi, A. B. (2012). Remarks on the mating 360
behaviours and success of blue swimming crab, Portunus pelagicus (Linnaeus, 1766) 361
through the induction of limb autotomy technique. Journal of Animal and Veterinary 362
Advances. 11 (8), 1149-1157. 363
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relationship and condition factors of West African blue crab (Callinectes pallidus) from 365
Ojo Creek, Lagos, Nigeria. American Journal of Research Communication, 1(3), 102-366
114. 367
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Waters. Fisheries Research, 21, 465-469. doi:10.1016/0165-7836(94)00294-7 369
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Primary Industries, Queensland, Australia, pp 171-177. 372
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crab. Marine Ecology Progress Series. 147, 77-85. Retrieved from 374
http://www.jstor.org/stable/24857346 375
Smith, L. D. (1990). Patterns of limb loss in the blue crab, Callinectes sapidus Rathbun, and the 376
effects of autotomy on growth. Bulletin of Marine Science. 46: 23-35. Retrieved from 377
http://www.ingentaconnect.com/content/umrsmas/bullmar/1990/00000046/00000001/art0378
0003#expand/collapse. 379
Stickney, R. R. (1972). Length-Weight relationships for several fishes and invertebrates in 380
Georgia coastal waters with condition factors for fish species. Skidaway Institute of 381
Oceanography Savannah, Georgia. 382
Sudha Devi, A. R., & Smija, M. K. (2015). Growth and moulting pattern in the freshwater crab 383
Travancoriana schirnerae. International Journal of Fisheries and Aquatic Studies, 3(2), 384
391-396. 385
Sukumaran, K. K., & Neelakantan, R. 1997. Length weight relationship in two marine portunid 386
crabs Portunus sanguinolentus (Herbst) and Portunus pelagicus (Linnaeus) from the 387
Kamalaka coast. Indian Journal of Marine Science, 26, 39-42. Retrieved from 388
http://eprints.cmfri.org.in/id/eprint/8255 389
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Tabash, F. A. (2001). Assessment and ecological characterization of the Blue Crab (jaiba, 390
Callinectes arcuatus) in the Gulf of Nicoya, Costa Rica. 391
www.una.ac.cr/biol/unalaw/english /crab.htm. [January 2, 2017]. 392
Villasmil, L., Mendoza, J., & Ferrer, O. J. M. (1997). Growth and mortality of the blue crab 393
Callinectes sapidus (Rathbun, 1896) in Lake Maracaibo. Ciencia (Maracaibo), 5, 7-15. 394
Waiho, K., Fazhan, H., & Ikhwanuddin, M. (2016). Size distribution, length-weight relationship 395
and size at the onset of sexual of the orange mud crab, Scylla olivacea, in Malaysian 396
waters. Marine Biology Research, 12(7), 726-738. doi:10.1080/17451000.2016.1200726 397
398
399
400
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Appendix
Carapace width and body weight increment of S. olivacea that being introduced with limb autotomized technique. All crabs molted
successfully and showed Stage 1 ovary (n=135).
Carapace Width Body Weight
No. of crab Before (cm) After (cm) Size of Increment (cm) Before (g) After (g) Size of Increment(g)
1 7.71 8.91 1.20 103.70 110.50 6.80
2 6.81 7.49 0.68 62.50 69.80 7.30
3 7.11 8.02 0.91 79.10 88.30 9.20
4 7.61 8.65 1.04 78.50 86.70 8.20
5 6.74 7.35 0.61 60.30 68.70 8.40
6 7.74 8.35 0.61 68.90 78.40 9.50
7 8.33 9.37 1.04 86.70 96.40 9.70
8 9.02 10.56 1.54 102.60 110.80 8.20
9 6.92 7.61 0.69 75.60 84.30 8.70
10 7.74 8.44 0.70 80.30 89.70 9.40
11 7.76 8.47 0.71 75.10 83.60 8.50
12 7.04 7.57 0.53 68.30 79.90 11.60
13 8.14 9.33 1.19 98.80 110.50 11.70
14 7.19 7.95 0.76 79.60 86.50 6.90
15 8.14 9.33 1.19 90.50 99.60 9.10
16 7.47 8.17 0.70 79.40 84.60 5.20
17 7.59 8.28 0.69 86.30 94.70 8.40
18 7.39 7.82 0.43 69.60 78.60 9.00
19 6.85 7.59 0.74 68.30 79.40 11.10
20 7.66 8.34 0.68 85.90 98.40 12.50
21 7.86 9.35 1.49 102.20 121.20 19.00
22 6.81 7.13 0.32 67.90 75.40 7.50
23 7.54 8.63 1.09 78.30 84.70 6.40
24 7.17 7.98 0.81 71.90 79.40 7.50
25 6.42 7.56 1.14 57.30 69.90 12.60
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26 6.44 7.45 1.01 51.80 63.80 12.00
27 7.95 8.96 1.01 67.70 76.80 9.10
28 6.68 7.32 0.64 55.10 67.90 12.80
29 6.98 7.76 0.78 69.40 80.30 10.90
30 7.17 8.34 1.17 72.90 83.40 10.50
31 6.45 7.38 0.93 52.00 63.70 11.70
32 6.56 7.31 0.75 54.10 63.70 9.60
33 6.19 7.06 0.87 44.30 52.80 8.50
34 7.27 8.07 0.80 77.00 85.70 8.70
35 6.85 7.64 0.79 66.10 75.90 9.80
36 6.59 7.31 0.72 57.10 65.60 8.50
37 7.86 8.54 0.68 63.80 71.50 7.70
38 6.84 7.96 1.12 65.50 76.30 10.80
39 6.88 7.56 0.68 63.40 75.10 11.70
40 6.33 6.92 0.59 51.20 56.50 5.30
41 6.52 7.42 0.90 51.60 57.40 5.80
42 7.61 8.76 1.15 77.30 86.90 9.60
43 7.75 8.41 0.66 95.40 101.20 5.80
44 8.73 9.52 0.79 136.80 148.80 12.00
45 8.76 9.45 0.69 115.80 128.50 12.70
46 8.21 9.18 0.97 109.60 124.30 14.70
47 8.11 8.41 0.30 98.60 101.20 2.60
48 7.12 8.35 1.23 65.40 70.80 5.40
49 8.12 9.52 1.40 139.80 148.80 9.00
50 7.71 8.55 0.84 107.80 111.00 3.20
51 7.81 8.63 0.82 76.90 88.30 11.40
52 7.90 8.01 0.11 68.30 79.70 11.40
53 5.90 6.97 1.07 50.60 60.40 9.80
54 6.81 6.93 0.12 48.60 56.80 8.20
55 8.61 9.66 1.05 114.70 126.50 11.80
56 6.85 7.59 0.74 75.30 84.30 9.00
57 5.95 6.56 0.61 64.20 69.70 5.50
58 9.09 9.79 0.70 88.50 97.80 9.30
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59 8.63 9.22 0.59 76.10 85.30 9.20
60 6.26 6.91 0.65 75.40 80.60 5.20
61 7.91 8.52 0.61 73.40 79.60 6.20
62 5.92 6.82 0.90 58.90 64.90 6.00
63 8.28 8.92 0.64 86.70 94.30 7.60
64 5.85 6.63 0.78 63.20 68.50 5.30
65 5.53 6.06 0.53 59.60 68.70 9.10
66 5.45 6.09 0.64 58.50 71.30 12.80
67 9.56 10.24 0.68 91.40 101.3 9.90
68 5.72 6.28 0.56 65.20 71.30 6.10
69 6.52 7.13 0.61 64.10 71.40 7.30
70 6.41 7.14 0.73 64.60 73.10 8.50
71 9.20 9.52 0.32 92.30 95.60 3.30
72 7.07 7.52 0.45 84.10 89.60 5.50
73 6.36 6.63 0.27 64.80 73.80 9.00
74 8.44 8.95 0.51 75.40 81.20 5.80
75 9.15 9.74 0.59 98.60 107.40 8.80
76 7.91 8.84 0.93 69.70 76.30 6.60
77 6.56 7.28 0.72 59.60 71.40 11.80
78 5.85 6.56 0.71 55.80 67.20 11.40
79 8.26 9.02 0.76 75.10 79.50 4.40
80 8.52 9.44 0.92 76.30 88.10 11.80
81 8.15 8.86 0.71 70.50 76.80 6.30
82 7.36 8.55 1.19 66.50 73.30 6.80
83 7.52 7.78 0.26 67.40 76.10 8.70
84 8.48 9.64 1.16 68.90 77.40 8.50
85 7.32 8.27 0.95 57.80 68.50 10.70
86 7.47 8.14 0.67 58.30 64.70 6.40
87 7.82 8.74 0.92 60.30 67.10 6.80
88 7.08 7.69 0.61 56.40 61.70 5.30
89 7.24 8.58 1.34 57.10 61.20 4.10
90 8.15 8.77 0.62 71.50 77.80 6.30
91 8.07 9.21 1.14 65.30 69.80 4.50
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92 7.77 8.84 1.07 59.80 64.60 4.80
93 7.33 8.02 0.69 58.20 63.10 4.90
94 6.83 7.85 1.02 55.80 67.20 11.40
95 7.32 8.39 1.07 61.70 68.50 6.80
96 6.76 7.35 0.59 56.90 61.60 4.70
97 7.53 8.42 0.89 60.70 67.90 7.20
98 7.63 8.56 0.93 61.80 68.10 6.30
99 7.49 7.95 0.46 59.60 65.30 5.70
100 7.68 8.09 0.41 61.80 66.70 4.90
101 7.76 8.59 0.83 64.30 71.20 6.90
102 8.58 9.54 0.96 72.40 81.20 8.80
103 7.93 8.82 0.89 65.30 69.60 4.30
104 7.84 8.49 0.65 63.10 69.80 6.70
105 7.14 8.24 1.10 60.80 68.50 7.70
106 7.84 8.98 1.14 72.90 83.60 10.70
107 7.83 8.54 0.71 70.60 79.50 8.90
108 7.93 8.98 1.05 75.40 85.20 9.80
109 7.24 8.36 1.12 68.90 77.90 9.00
110 7.26 7.75 0.49 69.70 76.50 6.80
111 7.74 8.33 0.59 70.80 77.30 6.50
112 7.35 8.07 0.72 69.80 74.30 4.50
113 7.13 7.83 0.70 66.40 75.10 8.70
114 7.68 8.38 0.70 74.30 83.10 8.80
115 7.07 7.73 0.66 66.70 71.80 5.10
116 7.44 8.22 0.78 69.50 76.30 6.80
117 8.44 9.35 0.91 79.60 87.90 8.30
118 8.05 9.26 1.21 77.80 88.40 10.6
119 8.87 9.84 0.97 88.30 92.10 3.80
120 7.16 7.95 0.79 68.30 74.80 6.50
121 6.27 6.65 0.38 59.70 68.30 8.60
122 6.63 7.39 0.76 68.10 78.90 10.8
123 6.56 7.29 0.73 67.10 71.70 4.60
124 7.86 8.48 0.62 75.90 79.90 4.00
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125 8.26 9.43 1.17 69.60 78.90 9.30
126 7.69 8.66 0.97 73.20 84.30 11.10
127 7.84 8.78 0.94 68.30 76.90 8.60
128 8.05 8.68 0.63 73.20 85.10 11.90
129 8.39 9.44 1.05 72.40 83.30 10.90
130 7.61 8.61 1.00 66.70 78.10 11.40
131 7.62 8.55 0.93 68.90 76.30 7.40
132 8.90 9.90 1.00 76.90 89.30 12.40
133 8.35 9.44 1.09 63.20 75.10 11.90
134 7.43 8.82 1.39 65.20 75.10 9.90
135 8.67 10.17 1.50 77.80 89.20 11.40
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Table 1. Mean oocyte diameter of S. olivacea before (control) and after the molt
(induced by the limb autotomy).
Mean oocyte diameter (µm)
Standard deviation n
Before (Control)
25.67
4.38
30
After (Introduced to limb autotomized technique)
34.76
12.13
135
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Table 2. Mean, standard deviation, highest and lowest carapace width and body weight
increments recorded after the crabs molted (n=135).
Mean Standard deviation
Highest increment
Lowest increment
CW (cm)
0.816
0.27
1.54
0.30
BW (g) 8.395 2.72 19.00 3.20
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Table 3. Correlation analysis for carapace width and body weight increments of S.
olivacea (n=135).
CW BW
CW Pearson Correlation 1 0.263**
Sig. (1-tailed) 0.001 N 135 135
BW Pearson Correlation 0.263** 1
Sig. (1-tailed) 0.001
N 135 135
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Table 4. Regression analysis for carapace width and body weight increments of S.
olivacea (n=135).
Model Sum of Squares df
Mean Square F Sig.
1 Regression 68.665 1 68.665 9.897 0.002b
Residual 922.702 133 6.938
Total 991.366 134
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Figure 1. (a) External morphology of Stage 1 ovary before the limb autotomy, (b)
External morphology of Stage 1 ovary after the crab molted, (c) Histological assessment
of Stage 1 ovary before the crab’s molt, (d) Histological assessment of Stage 1 ovary
after the crab molted. O: oocyte, F: follicle cell, N: nucleus, Og: oogonia.
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Figure 2. Frequency of carapace width increments of S. olivacea (n=135).
(cm)
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Songklanakarin Journal of Science and Technology SJST-2017-0375.R1 Ikhwanuddin
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Figure 3. Frequency of body weight increments of S. olivacea (n=135).
(g)
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Songklanakarin Journal of Science and Technology SJST-2017-0375.R1 Ikhwanuddin
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For Review Only
Figure 4. Regression analysis for carapace width and body weight increments of S.
olivacea with the equation y=2.61x + 6.27 (R2 =0.069) (n=135).
(cm)
(g)
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Songklanakarin Journal of Science and Technology SJST-2017-0375.R1 Ikhwanuddin
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