The Ecology of Sand Bubbler Crab at Pugu Beach, Lundu, Sarawak

THE ECOLOGY OF SAND BUBBLER CRAB AT PUGU BEACH, LUNDU, SARAWAK

Haleeda Natasya binti Ahmad Zawawi

(36167)

Bachelor of Science with Honours (Aquatic Resource Science and Management) 2015

UNIVERSITI MALAYSIA SARAWAK

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[The instrume nt was prepared by The Ce ntre for Acade mic Information Se rvices] The Ecology of Sand Bubbler Crab at Pugu Beach, Lundu, Sarawak

Haleeda Natasya binti Ahmad Zawawi (36167)

This project report is submitted in partial fulfillment of the requirements for the Degree of Bachelor of Science with Honours (Aquatic Resource Science and Management)

Faculty of Resource Science and Technology UNIVERSITI MALAYSIA SARAWAK 2015

Acknowledgements

Firstly, I want to express my gratitute to Allah for his blessings throughout the duration of my research and completion of this project. Special thanks to Dr. Siti Akmar Khadijah bt

Ab. Rahim as my Supervisor who give me guide, advice and expertise. Not to forget my examiner, Dr. Samsur Mohamad for the comments given to improve my project.

Next, I would like to thank my beloved mother, Norhayati binti Abu Hassan and families and friend for all the supports and beliefs.

Special thanks to the lab assistant Mr Richard Toh and Mr Mustafa Kamal for spending their times to help during sampling. Thanks also to postgraduate students, Norhakimi

Muhammad for all the advices to improve this report.

DECLARATION

I hereby declare that the work in this project is my own except for quotations and summaries which have been duly acknowledged. No portion of the work referred to in this dissertation has been submitted in support of an application for another degree qualification of this or any other university or institution of higher learning.

......

Haleeda Natasya binti Ahmad Zawawi

Aquatic Resource Science and Management

Department of Aquatic Science

Faculty of Resource Science and Technology

University Malaysia Sarawak

Table of Contents

Acknowledgement I Declaration II Table of content III – IV List of figures V – VI List of tables VII – VIII List of abbreviation IX Abstract 1 1.0 Introduction 2 – 3 2.0 Literature Review 4 2.1Taxonomy Classification 4 2.2 Recent Status 5 2.3 Habitat Influences 6 2.4 Behavior of Sand Bubbler Crab 6 2.5 Species Identification 7 – 9 2.6 Habitat Preferance 9 – 10 2.7 Importants to the ecosystem 10 3.0 Material and Method 11 3.1 Study Site 11 3.2 Sampling Method 12 3.2.1 Sampling Station 12 3.2.2 Sampling of Sand Bubbler Crab 13 3.2.3 Physico-chemical Parameter 13 3.3 Laboratory Work 13 3.3.1 Carapace Measurement 13 3.3.2 Species identification 14 3.3.3 Sediment Analysis 14 3.3.3.1 Particle Size Analysis 14 3.3.3.2 Total Organic Matter 15 3.4 Data Analysis 15 3.4.1 The Density of Crabs 15 3.4.2 Correlation Analysis 16

III

4.0 Results 16 4.1 Community Structure 16-17 4.2 Crabs Density 18 - 19 4.3 Carapace Measurement 19 - 21 4.4 CW and CL Classes of D. intermedia 22 - 24 4.5 Physico-chemical Parameter 24 - 29 4.6 Sediment Particle Size Analysis 30 - 31 4.7 Total Organic Matter 32 4.8 Correlation Analysis 33 5.0 Discussion 34 5.1 Sand Bubbler Crab, D. intermedia 34 5.2 The Distribution of D. intermedia 34 - 37 5.3 Total Organic Matter Availability 37 6.0 Conclusion 38 7.0 References 39 - 40 Appendixe 41 - 45

List of Figures

Figure 1 The varies shape of carapace posses by different species under 7 genus Scopimera (a,b.c). Figure 2 The varies formation of tooth at the middle of dactyl possess by 8 different species under genus Scopimera (a, c, e) Figure 3 Varies groove pattern of carapace posses by the species under 8 genus Dotilla. Figure 4 The map showing the location of the sampling site. 11 Figure 5 Illustration of sampling design by using line transect across the 12 intertidal area from high tide to low tide. Figure 6 The dorsal view of Dotilla intermedia. 17 Figure 7 The ventral view of Dotilla intermedia. 18 Figure 8 The present of setae on the abdomen part was used to 18 distinguish between two genus of sand bubbler crab, Dotilla and Scopimera. Figure 9 Male and female abdomen of D. intermedia. 18 Figure 10 Mean density of crabs (ind/m2) collected across the intertidal 19 area of Pugu Beach on November 2014. Figure 11 Mean density of crabs (ind/m2) collected across the intertidal 20 area of Pugu Beach on February 2015. Figure 12 Mean size of carapace width (mm) of D. intermedia across the 20 intertidal area of Pugu Beach on November 2014. Figure 13 Mean carapace lenght (mm) of D. intermedia across the 20 intertidal area of Pugu Beach on November 2014 Figure 14 Mean carapace width (mm) of D. intermedia across the 21 intertidal area of Pugu Beach on February 2015. Figure 15 Mean carapace lenght (mm) of D. intermedia across the 21 intertidal area of Pugu Beach on February 2015. Figure 16 Number of individual of D. intermedia based on carapace width 22 class size at Pugu Beach on November 2014. Figure 17 Number of individual of D. intermedia based on carapace 23 length class size at Pugu Beach on November 2014.

Figure 18 Number of individual of D. intermedia based on carapace width 23 class size at Pugu Beach on February 2015. Figure 19 Number of individual of D. intermedia based on carapace width 24 class size at Pugu Beach on February 2015. Figure 20 Mean salinity (PSU) of pore water across the intertidal area of 25 Pugu Beach on November 2014. Figure 21 Mean pH values of pore water across the intertidal area of Pugu 25 Beach on November 2014. Figure 22 Mean temperature (°C) of pore water across the intertidal area 26 of Pugu Beach on November 2014. Figure 23 Mean temperature (°C) of sediment across the intertidal area of 26 Pugu Beach on November 2014 Figure 24 Mean salinity (PSU) of pore water across the intertidal area of 28 Pugu Beach on February 2015 Figure 25 Mean pH of pore water across the intertidal area of Pugu Beach 28 on February 2015 Figure 26 Mean temperature (°C) of pore water across the intertidal area 29 of Pugu Beach on February 2015. Figure 27 Mean temperature (°C) of sediment across the intertidal area of Pugu Beach on February 2015. 29 Figure 28 Percentage of very coarse sand, coarse sand, medium sand, fine 31 sand, very fine sand and silt and clay across the intertidal area of Pugu Beach on November 2014 Figure 29 Percentage of very coarse sand, coarse sand, medium sand, fine 31 sand, very fine sand and silt and clay across the intertidal area of Pugu Beach on February 2015. Figure 30 Mean total organic matter (%) across the intertidal area of Pugu 32 Beach on November 2014. Figure 31 Mean total organic matter (%) across the intertidal area of Pugu 32 Beach on February 2015

List of Table

Table 1 List of known species of sand bubbler crabs under the genus 5 Scopimera. Table 2 List of known species of sand bubbler crabs under the genus 5 Dotilla Table 3 Pearson - Linear correlation between physico-chemical 32 parameters, sediment particle size and total organic matter and species density on November 2014 Table 4 Mean density values D. intermedia across the intertidal area of 39 Pugu Beach on November 2014. Table 5 Mean density values of D. intermedia across the intertidal the 39 intertidal area of Pugu Beach on February 2015 Table 6 The result of pore water and sediment parameters taken from 40 high tide to low tide zone at intertidal area of Pugu Beach on November 2015. Table 7 The result of pore water and sediment parameters taken from 40 high tide to low tide zone at intertidal area of Pugu Beach on February 2015. Table 8 Carapace measurement of crab samples collected from high tide 41 zone to low tide zone at intertidal area of Pugu Beach on November 2015. Table 9 Carapace measurement of crab samples collected from high tide 41 zone to low tide zone at intertidal area of Pugu Beach on February 2015. Table 10 Percentage of very coarse sand, coarse sand, medium sand, fine 41 sand, very fine sand and silt and clay of five quadrates at intertidal area of Pugu Beach for the first trip. Table 11 Percentage of very coarse sand, coarse sand, medium sand, fine 42 sand, very fine sand and silt and clay of five quadrates at intertidal area of Pugu Beach on February 2015. Table 12 Mean and standard deviation of percent total organic matter of 42 five quadrates at intertidal area of Pugu Beach for the first trip.

VII

Table 13 Mean and standard deviation of percent total organic matter of 43 eight quadrates at intertidal area of Pugu Beach for the second trip.

VIII

List of Abbreviations cm - Centimeter mm - Micrometer TOM - Total organic matter PSA - Particle size analysis µ - Micrometer SPSS - Statistical Process for Social Science

THE ECOLOGY OF SAND BUBBLER CRAB AT PUGU BEACH, LUNDU, SARAWAK Haleeda Natasya binti Ahmad Zawawi

Aquatic Resource Science and Management Programme Faculty of Resource Science and Technology Universiti Malaysia Sarawak

ABSTRACT

A study on ecology of sand bubbler crab was conducted at Pugu Beach, Lundu, Sarawak (22thNovember 2014 and 3rdFebruary 2015). The objectives of this study were to document the community structure of sand bubbler crabs, to study the distribution of sand bubbler crabs across intertidal area and to investigate the influence of salinity, temperature, pH, total organic matter and sediment particle size analysis on the distribution of these crab across the intertidal. The sampling was done using line transect and quadrate (1m x 1m) methods and the crabs were collected using PVC corer (3.6 cm). From this research, only one species of sand bubbler crab was found namely Dotilla intermedia. In total, about 230 individuals of D. intermedia were collected from Pugu Beach, Lundu, Sarawak. Pore water salinity (r = 0.623, p = 0.013) and sediment temperature (r = 0.564, p = 0.029) showed significant correlation with the density of D. intermedia. Thus, further study can be done to investigate the relationship of the others parameter on the density of D. intermedia.

Key words: Ecology, sand bubbler crab, Dotilla, density.

ABSTRAK

Kajian tentang ekologi ‘ketam pasir’ telah dijalankan di Pantai Pugu, Lundu, Sarawak (22thNovember 2014 and 3rdFebruary 2015). Tujuan kajian ini dijalankan adalah untuk mendokumentasikan struktur komuniti ‘ketam pasir’, mengkaji taburan ‘ketam pasir’ melintangi kawasan intertidal dan mengkaji hubungan antara parameter air liang dan parameter tanah terhadap taburan ‘ketam pasir’ melintangi kawasan intertidal. Kaedah yang digunakan adalah garisan pintas dan kuadrat dan ketam dikutip menggunakan PVC korer (3.6 cm). Hasil kajian mendapati hanya satu spesies’ketam pasir’ telah ditemui. Jumlah ketam yang dijumpai di Pantai Pugu, Lundu, Sarawak adalah 230 individu. Parameter air liang (r = 0.623, p = 0.013) dan suhu tanah (r = 0.564, p = 0.029) menunjukkan hubungan signifikan terhadap kepadatan ketam. Oleh itu, kajian harus dipanjangkan untuk mengkaji hubungan parameter lain terhadap ‘ketam pasir’.

Kata kunci: Ekologi, ‘ketam pasir’, Dotilla, kepadatan.

1.0 INTRODUCTION

Sand bubbler crab, from the family of Ocypodidae comprises a number of very small crabs with carapace size around 1 cm and can be found in sandy shore of tropical and subtropical region (McLachlan and Brown, 2006). This crab feeds on the organic materials contained in the sediment surface by sorting it using its mouth parts and leaves a distinctive pattern of sand pellets of sorted sediment radiating around its burrow (McLachlan and Brown, 2006).

Sandy shore becomes a dynamic environment where the physical structure of the marine habitat is influenced by the interaction among sand, waves and tides (McLachlan and Brown, 2006). It has a great socio-economic value as recreational resources, thus severely impacted by anthropogenic activity (McLachlan and Brown, 2010). Besides, sandy shore is one of the most resilient dynamic coastlines due to their ability in absorbing the wave energy that is driven by surf-zone water movement, thus carries sand offshore during storm and move it back onshore during calms (McLachlan and Brown, 2006).

Some keys adaptations of invertebrates that inhabit sandy beaches are mobile, able to burrow and rhythmic behaviours where they tend to react immediately with the changing in the environment condition during tidal, semi-lunar, lunar and seasonal. These adaptations are needed in order to survive with rapidly changed condition. These can be seen in sand bubbler crab population as they will descent into the burrow as it is an obvious method of escaping high temperature and undergo evaporative cooling process by entering the burrow to maintain the water in the branchial cavity (McLachlan and Brown,

2010).

Sandy beaches are inhabited by both micro and macro organisms and one of them are sand bubbler crabs. Most of them will move up over the beach from the surf zone when the tide comes, and move down onto the beach from the dunes on the falling tide (McLachlan

2 and Brown, 2006). This behaviour also can be seen in sand bubbler crab population as they are diurnally active during low tide (Clayton and Al-Kindi, 1998) and remained buried at night (McLachlan and Brown, 2006). During low tide, they will come out from their burrow for feeding, fighting, courtship and copulation (Koga and Murai, 1997).

Previous studies had focused on their life history (Suzuki, 1983), microhabitat movement (Koga, 1995), distribution and recruitment of pelagic larvae (Suzuki and

Kikuchi, 1990), mating behaviours (Koga and Murai, 1997), burrow defence behaviour

(Takahashi et al., 2001), wandering behaviour (Gherardi et al., 2002) and population biology (Litulo et al., 2005).

For the worldwide distribution, sand bubbler crab can be found in Japan (Takahashi et al., 2001; Suzuki and Kikuchi, 1990; Koga and Murai, 1997; Suzuki, 1983; Wong et al.,

2010), Afrika (Gherardi et al., 2002; Litulo et al., 2005), China (Wong at al., 2011),

Philippines (Wong at al., 2011), Taiwan (Wong et al., 2010), Singapore (Wong et al.,

2010), Hong Kong (Wong et al., 2010) and Thailand (Allen et al., 2011), but in Malaysia there is no publish report about sand bubbler crab yet.

Therefore, this study was conducted in order to (1) document community structure of sand bubbler crabs that inhabit Pugu Beach, (2) study the distribution of sand bubbler crabs across intertidal area and (3) investigate the influence of salinity, temperature, pH, total organic matter and sediment particle size analysis on the distribution of these crab across the intertidal.

2.0 LITERATURE REVIEW

2.1 Taxonomy Classification of Sand Bubbler Crab

Sand bubbler crab, small crab with carapce size around 1 cm consist of two genus,

Scopimera and Dotilla (Kemp, 1919). Sand bubbler crab from the genus Dotilla sometimes replaced the population of ghost crab (genus Ocypode) in some sandy shore areas

(McLachlan and Brown, 2006).

Kingdom: Animalia

Phylum: Arthropoda

Class: Crustacea

Order: Decapoda

Family: Ocypodidae

Subfamily: Scopimerinae

Genus: Scopimera

Genus: Dotilla Stimpson (1858)

2.2 Recent Status

In World Register of Marine Species (WoRMS) website, a total of 17 species of sand bubbler crab under the genus Scopimera (Table 1) and 12 species under the genus Dotilla

(Table 2) had been discovered recently.

Table 1: List of known species of sand bubbler crabs under the genus Scopimera. (Source: WoRMS)

Species Name The Founder Scopimera bitympana Shen, 1930 S. crabicauda Alcock, 1900 S. curtelsoma Shen, 1936 S. globosa De Haan, 1835 S. gordonae Serene and Moosa, 1981 S. inflate A. Milne – Edwards, 1873 S. intermedia Balss, 1934 S. investigatoris Alcock, 1900 S. kochi Roux, 1917 S. longidactyla Shen, 1932 S. philippiensis Wong, Shih and Chan, 2011 S. pilula Kemp, 1919 S. proxima Kemp, 1919 S. ryukyuensis Wong, Shih and Chan, 2010 S. sheni Wong, Shih and Chan, 2011 S. sigillorum Rathbun, 1914 S. tuberculata Stimpson, 1858

Table 2: List of known species of sand bubbler crabs under the genus Dotilla. (Source: WoRMS)

Species Name The Founder Dotilla sulcata Forskal, 1775 D. blanfordi Alcock, 1900 D. brevitarsis de Man, 1888 D. intermedia de Man, 1888 D. fenestrate Hilgendorf, 1869 D. malabarica Nobili, 1903 D. pertinax Kemp, 1915 D. profuga Nobili, 1903 D. sigillorum Rathbun, 1914 D. wichmanni de Man, 1892 D. affinis Alcock, 1900 D. clepsydrodactyla Alcock, 1900

2.3 Habitat Influences

The constant exchange of sand, organic matter and nutrients availability that occur at beach influence the distribution and growth of organisms that inhabit beach area (McLachlan and

Brown, 2006). Besides, the physical processes such as the action of waves and tides can alter the community structure of the macroinfauna. It is because, they have to adapt to life in the sand to ensure that the supply of oxygen and food are sufficient even when they are not protected from wave action during high tide. Desiccation is another problem that organisms have to face especially when the tide is low (Ahmad et al., 2011).

Sandy shores intertidal organisms are usually burrowers in order to adapt in sandy beach area. Their burrowing ability are affected by several factors like size of body, sediment particle size and the temperature of water. On the other hand, the composition of intertidal organisms at the sandy shore increase when going down to lower tide zone but the diversity of organisms is higher at the middle tide zone (Ahmad et al., 2011).

2.4 Behavior of Sand Bubbler Crab

The burrowing cycle of this ocypodid is differ with soft-bodied animals, such as worms and mollusks as their body are able to elongate but take more times for digging compared to sand-burrowing arthropods. Sand bubbler crab with fixed body shape covered by exoskeleton do burrows using it jointed appendages, thus enable them to burrow rapidly into dry or moist sand, whereas worms and mollusks only can burrow into moist sand.

Besides, sand bubbler crab burrows permanently and in sideway form (McLachlan and

Brown, 2006).

Allen et al. (2011) stated that sand bubbler crabs feed on organic matters in sediment surface using their chelipeds to scrape sediment the sediment into their mouth where the organic matterial will be separated from the inorganic material by floatation mechanism.

The inorganic material then will be rejected from the base of their mouth as feeding pellets, thus will be pinched off by chela and passed through the leg. The movement pattern of these crabs during feeding are in radial form.

2.5 Species Identification

According to Wong et al. (2010), carapace is using to differentiate between species under genus Scopimera (Figure 1). Their carapace is slightly broader than long with inflated (S. globosa and S. ryukyuensis) and convex shape (S. intermedia). Besides, the surface of carapace covered by tubercles. Besides, they also can be distinguish by observing the formation of tooth of dactylus (Figure 2). The species of Dotilla species can be differentiate by observing the groove pattern of the carapace (Figure 3).

Figure 1: The varies shape of carapace posses by different species under genus Scopimera (a,b.c). (Adopted from Wong et al., 2010).

Figure 2: The varies formation of tooth at the middle of dactyl possess by different species under genus Scopimera (a, c, e). (Adopted from Wong et al., 2010).

Based on Allen et al. (2011), carapace of the species under genus Dotilla also broader than long. But, its surface sculptured with groove rather than tubercles. Besides, the formation of distinct tooth can be seen at the middle of dactylus.

Figure 3: Varies groove pattern of carapace posses by the species under genus Dotilla. (Adopted from Kemp, 1919)

2.6 Habitats Preferance

Sand bubbler crab can be found on sandy or muddy estuaries and tidal flat where they dig burrows to hide from predator and avoid from high tide (Takahashi et al., 2001). Based on

Macnae (1968), Scopimera and Dotilla prefer sandy shore except for D. fenestrata which was found in mangrove swamps. However, this crab sometimes can be found in both areas with a preference well-drained area (Dray and Paula, 1998).

There were several studies conducted in intertidal area of East African sandy shore which dominated by sand bubbler crab D. fenestrata (Litulo et al., 2005). On sandy beach of Red Sea, D. sulcata was found at the lower parts of the intertidal zone which forming large population (Fishelson, 1983). Based on Hilgendorf (1869), D. fenestrata be the most and dominant brachyuran of may East African sandy shore where they were found abundantly at intertidal area (Litulo et al., 2005).

Clayton and Al-Kindi (1998) mentioned that genus Scopimera is found further east than Dotilla. In Thailand, two species from genus Dotilla, D. intermedia and D. wichmanni have been discovered at sandy shore area (Wong et al., 2010). In sandy shore of Japan, S. globosa was found inhabit the upper littoral zone of Tomioka Bay (Suzuki and Kikuchi,

1990; Suzuki, 1983) and intertidal sandy-muddy flat of Wajiro Beach, Fukuoka (Koga,

1995; Koga and Murai, 1997).

2.7 Importants to the Ecosystem

Sand bubbler crab plays a major role in the ecology of sandy shore, presenting locally patches of high density and contribute for the consumption of organic matter availability in the superficial layer of the sediment (Dray and Paula, 1998). Besides, their burrowing activities enhance the oxidation process in the anaerobic layers (Fishelson, 1983).

3.0 MATERIALS AND METHODS

3.1 Study Site

The samplings were done on 22th November 2014 and 3rd April 2015 at sandy beach of

Pugu Beach, Lundu (N 01°46’01.5’’, E 109°51’29.8’’). The coordinate was recorded using

Global Positioning System (GARMIN, GPSmap 60CSx).

Figure 4: The map showing the location of the sampling site.