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MAPPING AND NUTRIENT ENRICHMENT STUDIES OF SEAGRASS BEDS IN SEPANGGAR BAY, SABAH

Marjorie Anak Albert Chagat

a

9 I E

Master of Science (Aquatic Biology)

2005

Pusat Khidmat Makluwuat Akasjemiic tINIVERSITI MALAYSIA SARAWAK

MAPPING AND NUTRIENT ENRICHMENT STUDIES OF SEAGRASS BEDS IN SEPANGGAR BAY, SABAH

P. KHIOMAT MAKLUMAT AKAOEMIK

iiiiiiiiilTl'liIb 1111111111 1000246264

MARJORIE ANAK ALBERT CHAGAT

A thesis submitted in fulfillment of the requirements for the degree of Master of Science

Faculty of Resource Science and Technology UNIVERSITI MALAYSIA SARAWAK

2005

ACKNOWLEDGEMENTS

Deepest gratitude to my father, Albert Chagat Lemada, mother, Esther Agit Beriak,

brothers, Johannes, Alexander, Samuel Mengga and Gordon and my only sister Angelo

Enching for the encouragement and perseverance throughout these years. Not forgotten,

friends, Jessica Bartholomew Ujah, Flora Bungan Balang, Inja Hellegers Achong,

Pauline Robert Ero, Felicia Dorothea, Priscilla Simba and others not mentioned here.

The staffs, officers and individuals, who helped during the field surveys and lab work,

thank you for the kindness and memorable moments, especially to Pakcik Sahrol

Hamzah, Pakcik Megat, Pakcik Zaidi and Pakcik Fardos. Special thanks to my

supervisor, Dr. Norhadi Ismail for his support, assistance, guidance, and supervision

throughout the course of this study. Lastly, I wish to thank the Ministry of Science,

Technology and Environment (MOSTE) for the scholarships awarded under the National

Science Fellowship, the Malaysian Center for Remote Sensing (MACRES) for the SPOT

satellite image and Semonggok Research Center for the nutrient analysis.

11

Abstract

(Remotely sensed images from SPOT-4 satellite were used to map the distribution of

seagrass habitat in Sepanggar Bay, Sabah. Ground truthing was carried out at the

study sites to determine the actual underwater features and then compared to those in

the images. Five major cover types were identified during the survey, namely seagrass,

seaweeds, mix seagrass and seaweeds, live and dead corals and bare sand. Seven species

of seagrasses were found including Enhalus acoroides, Cymodocea serrulata, C.

rotundata, Halophila ovalis, Thalassia hemprichii, Halodule uninervis and Syringodium

lsoetifollum. Digital image processing software (Integrated Land and Water Information

System, ILWIS) was applied to the images for the development of seagrass thematic

maps using a supervised classification procedure. ) The overall maps accuracies for North

Sepanggar Bay, Sepanggar Island and South Sepanggar Bay were 63.5 %, 56.3 % and

59.2 %, respectively. Despite the low accuracy, the present baseline seagrass maps are

still useful for conservation and management plan of the area.

Along with mappings, nutrient enrichment studies were also conducted to determine the

nutrient status of the seagrass in the bay. Enhalus acoroides at South Sepanggar Bay

and Cymodocea serrulata at Sepanggar Island were enriched with two loads of time-

released fertilizer; high load (+NPK; 70.4 gm-2) and low load (+NPK; 35.2 gm-2). After 3

months of fertilization, tissue nitrogen concentrations in aboveground and belowground

parts of the E. acoroides were significantly increased in response to both the low and

high loads of fertilizers. However, the aboveground tissues of C. serrulata did not exhibit

significant results in response to low load fertilization. Other parameters, chlorophyll

production, shoot growth rates and biomass was not significantly increased during the

iii

three months enrichment period. Hence, tissue nitrogen content is the appropriate

parameter for short study using time-released fertilizer. Concentrations of ammonium

and phosphate in the sediment pore water and water column were also increased. At the

end of the nutrient additions ammonium concentrations in pore water and water column

at Station 1 (Sepanggar Island) were found increased with concentrations in the

fertilized plots ranged from 0.006 - 0.008 µM and 0.004 - 0.006 µM in the control plots in

response to both high and low load fertilizations. However, the concentrations of

phosphate in sediment pore water and water column in fertilized plots (0.003 - 0.004

µM) were comparable to that of the controls (0.004 . tM), both under high and low load

enrichments. At Station 2 (South Sepanggar), results indicated that concentrations of

ammonium and phosphate increased in the fertilized plots (ranging from 0.008 to 0.018

pM and 0.005 to 0.011 pM respectively) at the end of the enrichment experiments as

compared to those in the control plots (ammonium 0.003 - 0.011 pM and phosphate 0.001

- 0.006 µM).

iv

Abstrak

Pemetaan dan K$jian Pengkayaan Nutrien Kawasan Rumput Laut di Teluk Sepanggar,

Sabah

Imej penderiaan jauh dari satelit SPOT-4 telah digunakan dalam pemetaan taburan

habitat rumput laut di Teluk Sepanggar, Sabah. Pengamatan di lapangan dilakukan

untuk menentukan cirl-clri sebenar dibawah air dan kemudiannya dibandingkan

dengan yang terdapat pada imej. Dalam tiiljauan tersebut, 5 jenis `covertype' utama

telah dikenalpasti iaitu rumput laut, rumpai laut, campuran rumput dan rumpai laut,

karang hidup dan mati serta pasir. Tujuh spesies rumput laut juga telah ditemui iaitu

Enhalus acoroides, Cymodocea serrulata, C. rotundata, Halophila ovalis, Thalassia

hemprichii, Halodule uninervis dan Syringodium isoetifolium. Perisian pemprosesan

imej digital (Integrated Land and Water Information System, ILWIS) telah digunakan

dalam pembentukan peta bertema melalui prosedur pengkelasan berpenyelia.

Ketepatan keseluruhan bagi peta Teluk Sepanggar Utara ialah 63.5 % 56.3 % untuk

Pulau Sepanggar dan 59.2 % untuk Teluk Sepanggar Selatan. Walaupun ketepatan

keseluruhan peta peta tersebut adalah rendah, peta yang dihasilkan masih boleh

difadikan rujukan dalam pengurusan dan pemuliharaan habitat rumput laut di

ka wasan ini.

Disamping pemetaan, satu k$jian pengkayaan juga telah dilakukan untuk menentukan

status nutrien bagi rumput laut di teluk tersebut. Dalam k4jian ini, Enhalus acoroides

di Teluk Sepanggar Selatan dan Cymodocea serrulata di Pulau Sepanggar telah

diberikan bgja kadar lambat-lepas menggunakan dua ferns muatan iaitu muatan tinggi

V

(+NPK, 70.4 gm-2) dan muatan rendah (+NPX- 352 gm-2). Selepas Liga bulan

pemb4jaan, kebanyakan kandungan nitrogen di dalam tisu bahagian atas dan bawah

tanah bagi kedua-dua spesies rumput laut tersebut didapati telah meningkat secara

signifikan sebagai tindakbalas terhadap b$ja yang diberikan. Walaubagaimanapun, tisu

bahagian atas tanah daripada C. serrulata tidak memberi tindakbalas signifikan

terhadap muatan b4ja rendah. Parameter lain iaitu penghasilan klorofil, kadar

pertumbuhan pucuk dan biomas tidak memberi hasil signifikan separ; jang tempoh

eksperimen pembajaan Liga bulan tersebut. Oleh itu, kandungan tisu nitrogen

merupakan parameter yang sesuai untuk k$ jian jangka pendek menggunakan b4ja jenis

lambat-lepas dalam menilai status nutrien spesies yang dik4ji. Kepekatan kandungan

ammonium dan fosfat dalam air liang sedimen dan di dalam turus air juga meningkat.

Di Stesen 1 (Pulau Sepanggar), kepekatan ammonium dalam air hang sedimen adalah

di dalam julat 0.006 - 0.008 µM berbanding plot kawalan dalam julat 0.004 - 0.006µM,

sebagai tindakbalas terhadap pembijaan muatan tinggi dan rendah.

Walaubagaimanapun, kepekatan fosfat dalam air hang sedimen dan di dalam turus air

tidak jauh berbeza berbanding antam plot yang dib4jai (0.003 - 0.004 µM) dan plot

kawalan (0.004 µM) dalam pembgjaan muatan tinggi dan rendah. Bagi Stesen 2 (Teluk

Sepanggar Selatan), kepekatan ammonium dan fosfat dalam plot yang diberi b4ja

meningkat berbanding plot kawalan, iaitu masing-masing 0.008 - 0.018 µM bagi

ammonium dan 0.005 - 0.011 µM bagi fosfat berbanding plot kawalan yang

mengandungi ammonium 0.003 - 0.011 µMdan fosfat 0.001- 0.006, uM.

vi

Pusat Khidmat Maklumat Akademik U ti IVE kS I Ti MALAYSIA SA RAw'A K

Table of Contents

Title

Acknowledgements

Abstract

Abstrak

Table of Contents

List of Tables

List of Figures

List of Abbreviations

CHAPTER 1 Introduction

1.1 Objectives

1.2 Scope of Studies

CHAPTER 2 Literature Review

2.1 Seagrass

2.1.1 Introduction

2.1.2 Importance

2.1.3 Threats

2.2 Remote Sensing and Seagrass Mapping

2.2.1 Remote Sensing Processes

Page

i

ii

111

V

vii

xi

xv

xx

1

5

6

8

8

8

14

18

21

25

vii

CHAPTER 3 Materials and Methods 29

3.1 Seagrass Distribution and Habitat Mapping

3.1.1 Study Site

3.2 Mapping of Seagrass Communities

3.2.1 Ground Truthing

3.2.2 Image Processing

3.2.2.1 Supervised Classification

3.3 Ecological Study

29

29

31

32

32

33

34

3.3.1 Seagrass Biomass 34

3.3.1.1 Study Sites 34

3.3.1.2 Sampling Procedures 35

3.3.2 Seagrass Enrichment Experiment 36

3.3.2.1 Study Sites 36

3.3.2.2 Sediment Particle Size 37

3.3.2.3 Experimental Design of Enrichment Experiment 38

3.3.2.4 Fertilization Method 39

3.3.2.5 Pore Water and Water Column Nutrient

Concentrations 40

3.3.3 Plant Responses Monitored 41

3.3.3.1 Growth and Morphological Responses 42

3.3.3.2 Physiological Response 44

3.3.4 Data Analysis 45

vin

CHAPTER 4 Results 46

4.1 Seagrass Distributions in Sepanggar Bay, Sabah

4.2 Habitat Mapping of Seagrass Communities

4.3 Ecological Study

4.3.1 Seagrass Biomass

4.3.2 N- Enrichment Experiment

4.3.2.1 Physico-chemical Parameters

4.3.2.2 Sediment Particle Size

4.3.2.3 Sediment Pore Water and Seawater Column

Nutrient Concentrations

4.3.3 Response to Nutrient Enrichment

4.3.3.1 N- Contents

4.3.3.2 Chlorophyll Production

4.3.3.3 Growth Rates

4.3.3.4 Biomass

46

52

59

59

59

59

60

61 67

67

71

75

77

CHAPTER 5 Discussions 81

5.1 Seagrass Distribution and Habitat Mapping at Sepanggar Bay 81

5.1.1 Mapping Accuracy 82

5.2 The Nutrient Enrichment Study of Seagrass at Sepanggar Bay 85

CHAPTER. 6 Conclusions 90

6.1 Remote Sensing 90

6.2 Ecological Study 93

ix

References 94

Appendices

x

List of Tables

Table 2.1 List of seagrass species and their geographical distribution

(modified from Hemminga & Duarte, 2000 and **Kuo, 2000). 10

Table 2.2 The average seagrass primary production compared to other

ecosystems. 15

Table 3.1 Classification system for land-cover data sets used in Sepanggar

Bay seagrass mapping. 33

Table 3.2 Wentworth grade classifications (Buchanan, 1971). 38

Table 4.1 Distribution of seagrass species in 3 main areas of Sepanggar Bay. 47

Table 4.2 Confusion matrix of test data sets of North Sepanggar area from

supervised classification. 53

Table 4.3 Confusion matrix of test data sets of South Sepanggar area from


Table 4.4 Confusion matrix of test data sets of Sepanggar Island area from


Table 4.5 The physico-chemical parameters measured at Station 1 (Sepanggar

Island) and Station 2 (South Sepanggar Bay) at the end of the

enrichment experiments. 60

Table 4.6 Sediments particle's size at Station 1 (Sepanggar Island), Station 2

(South Sepanggar Bay) and Station 3 (North Sepanggar Bay). 60

I

xi

Table 4.7 Means concentrations of PO43- (pM) and NH4+ (pM) in sediment pore

water and seawater column in the fertilized and control plots of

Station 1 (Sepanggar Island) and Station 2 (South Sepanggar) prior

to three months of fertilization.

Table 4.8 Means concentrations of P043- (pM) and NH4* (pM) in sediment pore

water and seawater column in the fertilized and control plots of

Station 1 (Sepanggar Island) and Station 2 (South Sepanggar) after

three months of fertilization.

Table 4.9 A summary of two-way ANOVA on phosphate and ammonium

concentrations in sediment pore water and seawater column in

response to low and high load fertilization.

Table 4.10 Summary of two-way ANOVA on N-content in aboveground and

belowground tissues of Cymodocea serrulata in enriched and control

plots (low load fertilization) at the end of the experiment at Station

1 (Sepanggar Island).


belowground tissues of Cymodocea serrulata in enriched and control

plots (high load fertilization) at the end of the experiment at Station

1 (Sepanggar Island).


belowground tissues of Enhalus acoroides in enriched and control

61

63

64

67

68

plots (low load fertilization) at the end of the experiment at Station

2 (South Sepanggar). 69

xii


belowground tissues of Enhalus acoroides in enriched and control

plots (high load fertilization) at the end of the experiment at Station

2 (South Sepanggar).

Table 4.14 Results of two-way ANOVA on chlorophyll a and b in the leaf of

Cymodocea serrulata after 3 months under low load fertilization at

Station 1 (Sepanggar Island).


Cymodocea serrulata after 3 months under high load fertilization at



Enhalus acoroides after 3 months under low load fertilization at

Station 2 (South Sepanggar).


Enhalus acoroides after 3 months under high load fertilization at


Table 4.18 Summary of two-way ANOVA on growth rate of Cymodocea

serrulata in enriched and control plots at the end of the enrichment

experiment at Station 1 (Sepanggar Island).

Table 4.19 Summary of two-way ANOVA on growth rate of Enhalus acoroides

in enriched and control plots at the end of the enrichment

experiment at Station 2 (South Sepanggar).

Table 4.20 Summary of two-way ANOVA on biomass of Cymodocea serrulata in

low load fertilization and control plots at the end of the enrichment


70

71

72

73

74

75

76

77

11111

Table 4.21 Summary of two-way ANOVA on the biomass of Cymodocea

serrulata in high load fertilization and control plots at the end of the

enrichment experiment at Station 1 (Sepanggar Island). 78

Table 4.22 Summary of two-way ANOVA on the biomass of Enhalus acoroides

in low load fertilization and control plots at the end of the

enrichment experiment at Station 2 (South Sepanggar). 79

Table 4.23 Summary of two-way ANOVA on the biomass of Enhalus acoroides

in high load fertilization and control plots at the end of the

enrichment experiment at Station 2 (South Sepanggar). 80

xiv

List of Figures

Figure 2.1 Declines in species presence with distance along the main current

system from the Malaysian center of species richness in the Indo-

Pacific region (c. f. Mukai, 1993). 10

Figure 2.2 Remote Sensing Processes. 28

Figure 3.1 Satellite image of the study area in Sepanggar Bay, Kota Kinabalu,

Sabah, Malaysia (Source: ERMBorneo Sdn. Bhd. ). -30

Figure 3.2 Satellite image of the study area (Sepanggar Bay) taken from SPOT 4

satellite in 14 April 2000.31

Figure 3.3 A SPOT-4 image of Sepanggar Island (Station 1) showing location of

transects (Ti, T2 and T3) and enrichment site (E). 36

Figure 3.4 A SPOT-4 image of South Sepanggar Bay (Station 2 and 3) showing

transects (Ti, T2 and T3) and enrichment site (E). 37

Figure 3.5 The experimental plot set-up or randomized complete block used in `in

situ'fertilization exhibited treatment and control plots. 39

Figure 3.6 In situ fertilizer additions during seagrass enrichment experiment. 40

Figure 3.7 Hole punch method employed to measure the growth and production

rates of seagrasses (Enhalus acoroides and Cymodocea serrulata). 43

Figure 4.1 Enhalus acoroides meadows in North Sepanggar near to petroleum

depot (D) and timber factory M. 47

Figure 4.2 Enhalus acoroides 48

Figure 4.3 Halophila ovalis beds in Kuala Menggatal (South Sepanggar). 49

Figure 4.4 Halophila ovalis. 49

xv

Figure 4.5 Halophila ovalis beds covered by silts near Kuala Sungai Menggatal. 50

Figure 4.6 Cymodocea spp. (C) mixed with Enhalus acoroides (E) in Sepanggar

Island. 50

Figure 4.7 Syringodium isoetifolium (S) and Thalassia hemprichii (T) found in

subtidal area of Sepanggar Island. 51

Figure 4.8 Map of seagrass distribution in area of North Sepanggar Bay. The

coordinate system is the Universal Transverse Mercator (UTM) Grid;

each grid represents 1000 m on the ground. 56

Figure 4.9 Map of seagrass distributions in area of South Sepanggar Bay. The



Figure 4.10 Map of seagrass distribution in area of Sepanggar Island. The



Figure 4.11 The concentration of ammonium (pM) in pore water under low load

fertilization at Station 2 (South Sepanggar Bay) after 3 months of

enrichment. Bars represent means of 4 replicates samples ±1S. E.

Different letters (a, b) indicate significant differences between means

(p<0.05). 65

Figure 4.12 The concentration of phosphate (pM) in water column under low load

fertilization at Station 1 (Sepanggar Island) after 3 months of



(p<0.05). 65

xvi

Figure 4.13 The concentration of phosphate (pM) in water column under low load




p<0.05). 66

Figure 4.14 The concentration of ammonium (pM) in water column under low load




(p<0.05). 66

Figure 4.15 Nitrogen content as % per g dry weight in a) aboveground parts and b)

belowground parts of Cymodocea serrulata in control and fertilized

plots(low load fertilization) at Station 1 after 3-months of fertilization.

Bars represent means of 4 aboveground; 6 belowground samples ±1

S. E. a, b Denote significant differences between means (p<0.05). 67


belowground parts of Cymodocea serrulata in control and fertilized

plots (high load fertilization) at Station 1 after 3-months of

fertilization. Bars represent means of 2 aboveground; 2 belowground

samples ±1S. E. a. b Denote significant differences between means

(p<0.05). 68


belowground parts of Enhalus acoroides in control and fertilized plots

(low load fertilization) at Station 2 after 3-months of fertilization.




belowground parts of Enhalus acoroides in control and fertilized plots

(high load fertilization) at Station 2 after 3-months of fertilization



Figure 4.19 Production of chlorophyll a and chlorophyll b (mean t1 SE) in the leaf

of Cymodocea serrulata after 3 months under low load fertilization

compared with untreated controls. 71


of Cymodocea serrulata after 3 months under high load fertilization

compared with untreated controls. 72


of Enhalus acoroides after 3 months under low load fertilization

compared with untreated controls.


of Enhalus acoroides after 3 months under high load fertilization

compared with untreated controls.

Figure 4.23 Growth rates of Cymodocea serrulata at Staion 1 (Sepanggar Island)

after 3 months of low load enrichment (A) and high load enrichment

(B). Bars represent mean ±1 SE.

73

74

75

xviii

Figure 4.24 Growth rates of Enhalus acoroides at Station 2 (South Sepanggar)

after 3 months of low load enrichment (A) and high load enrichment

(B). Bars represent mean ±1 SE.

Figure 4.25 Aboveground (A) and belowground (B) biomass (g DW M-2) of

Cymodocea serrulata (mean ±1 SE) in fertilized and control plots in

response to low load 3 fertilization at the end of the experiment at


Figure 4.26 Aboveground (A) and belowground (B) biomass (g DW M-2) of

Cymodocea serrulata (mean ±1 SE) in fertilized and control

treatments in response to high load fertilization at the end of the


Figure 4.27 Aboveground (A) and belowground (B) biomass (g DW M-2) of Enhalus

acoroides (mean ±1 SE) in fertilized and control treatments in

response to low load fertilization, 3 months after the enrichment at


Figure 4.28 Aboveground (A) and belowground (B) biomass (g DW M-2) of Enhalus

acoroides (mean ±1 SE) in fertilized and control treatments in

response to high load fertilization, 3 months after the enrichment

experiment at Station 2 (South Sepanggar).

76

77

78

79

80

xix

List of Abbreviations

CEES

CSIRO

CZCS

ERS

GIS

ICZM

ILWIS

Landsat MSS

Landsat TM

MACRES

MOSTE

NRSC

ORSER

SPOT-4

SPOT XP

SPOT XS

SRP

UNCED

UNESCO

Center for Energy and Environmental Studies

Commonwealth Scientific and Industrial Research Organization

Coastal Zone Color Scanner

European Remote Sensing Satellite

Geographic Information System

Integrated Coastal Zone Management

Integrated Land and Water Information System

Land Satellite Multispectral Scanner

Land Satellite Thematic Mapper

Malaysian Center for Remote Sensing

Ministry of Science, Technology and Environment

National Remote Sensing Center

Office for Remote Sensing of Earth Resources

Systeme Probatoire de 1' Observation de la terre 4

Systeme Probatoire de 1' Observation de la terre Panchromatic

Systeme Probatoire de 1' Observation de la terre Multispectral

Soluble Reactive Phosphate

United Nations Conference on Environment and Development

United Nations Educational, Scientific and Cultural Organization

CHAPTER 1

Introduction

The importance of seagrasses and their role in many ecosystems has been extensively

documented (Thayer et al. 1975; Phillips, 1982; Zieman et al. 1989). Seagrasses are

known worldwide for its diversity and production (Zieman & Wetzel, 1980). The primary

productivity of seagrass ecosystems and their contribution of organic matter to inshore

food webs are substantial. Its primary productivity is among the highest measured (400

- 500 gC/m2/year; Hemminga & Duarte, 2000) and thus supports diverse flora and fauna,

including coastal fisheries productivity (Fortes, 1990; Coles et al. 1993). Some studies

reported that net primary productivity values of seagrass were in the range of 2- 18 g

cm-2 d-1, with tropical and subtropical lagoons showed the highest values (e. g., Hillman et

al. 1989).

In addition, the presence of seagrass meadows in coastal areas does increase organic

inputs to the sediments, not only through their own detritus but also through the

trapping of suspended particles (Ward et al. 1984; Duarte & Chiscano, 1999; Gacia et al.

1999). Their roots and rhizomes bind millions of acres of shallow water sediment in the

coastal waters and simultaneously baffling waves and currents with their leafy canopy

(Ginsberg & Lowenstam, 1958; Taylor & Lewis, 1970; Den Hartog, 1971; Fonseca et al.

1983; Fonseca et al. 1996). Although recognized for their value and primary production

where they occur, the distribution of seagrasses is not well known, as it should be for

proper management (Wyllie-Echeverria & Olson, 1994).

1

To sustain a high productivity, seagrasses require a substantial amount of nutrients.

Nutrient uptake by seagrass blades and their associated epiphytes and macroalgae as

well as roots could improve water quality (Harlin & Throne-Miller, 1981). The death of

leaves and other plant parts, however, leads to constant drain of nutrients, as nutrients

are a component of these lost plant parts (Stapel, 1997). Thus, nutrients loss must be

replenished to allow the continued growth and persistence of the seagrasses (Hemmings

et al. 1991).

Although tropical seagrass meadows are self-sustaining systems in which most nutrients

are captured in the large seagrass biomass and are efficiently recycled within the system

(Nienhuis et al. 1989), this is only true for coral island seagrass. Study by Worm et al.

(2000) reported that nutrient concentrations varied through time and among sites, with

sediment depth, distance from the source and fertilizer load. However, the negative

effects of excessive inputs of organic matter or nutrient on seagrass growth have led to

the notion that highly productive seagrass meadows may `poison' themselves by driving

the sediments conditions to stressful level (Hemminga & Duarte, 2000).

Seagrasses are also often impacted by human activities due to their location in the

coastal zone (Fonseca & Mark, 1998). However, currently there is limited number of

available information on seagrass study in Sepanggar Bay that necessitates a scientific

effort to increase our knowledge on this coastal ecosystem where the environmental

pressures due to human activities are increasing rapidly. Because of their relatively

high (compared to phytoplankton) light requirements (Kenworthy & Haunert, 1991)

seagrasses occur in shallow, near shore waters, a situation that makes them extremely

susceptible to damage by human activity such as nutrient loading (Short & Burdick,

2

1996), light reduction (Dennison et al. 1993; Kenworthy & Haunert, 1991), and propeller

scarring (Sargent et al. 1995). Marine fauna such as dugongs (Dugong dugon) and green

turtles (Chelonia mydas) have been threatened as their most dependant habitat, the

seagrass beds, being in danger of extinction.

The Regional Environment Impact Assessment and Shoreline Management Plan West

Coast of Sabah prepared by the Danish Hydraulic Institute (DHI, 1999) for the Ministry

of Culture, Environment and Tourism, Sabah recommended that Sepanggar Island

should be protected due to its ecological importance. Therefore, seagrass meadows found

along the coastlines of Sepanggar Bay are appropriate for resource study as the plants

are threatened by various developmental activities including coastal structures or

reclamation works especially in the west, east and south of Sepanggar Bay.

It is important to document seagrass species, the taxonomic diversity and distribution of

seagrass and to identify areas requiring conservation measures to prevent significant

lost of areas and species. This is in line with Agenda 21, the comprehensive action plan

adopted by the United Nations Conference on Environment and Development (UNCED)

in 1992, which encourage the identification and conservation of marine ecosystems

exhibiting high levels of biodiversity and productivity. Unfortunately, there have been

very few studies on the distribution and ecology of seagrasses in Malaysia (Norhadi,

1993; Japar Sidik et al. 1996; Ethirmannasingam et al. 1996). A better coastal zone

management plan is also needed so that techniques to restore seagrass meadows in this

country can be developed in the near future especially, where there is potentially loss or

degradation of existed seagrass meadows. And hopefully, with the help of data from this

study, other marine resources associated with seagrass meadows can also be assessed.

3

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