Coral reef health condition based on herbivorous fish density in Pulau Tiga Subdistrict, Natuna District

CORAL REEF HEALTH CONDITION
BASED ON HERBIVOROUS FISH DENSITY
IN PULAU TIGA SUBDISTRICT,
NATUNA DISTRICT

DEDY DAMHUDY

POST GRGDUATE SCHOOL
BOGOR AGFUCULTURAL UNIVERSITY
BOGOR
2009

THESIS STATEMENT AND INFORMATION SOURCE
Hereby I confirmed that the thesis with title "Coral Reef Health Condition based
on Herbivorous Fish Density in Pulau Tiga Subdistrict, Natuna District'' is purely
my own proposal with support from Assistance Commission and by no means
being proposed on the any form to any universities1 institutes. Information
sourced and cited by other references which is not my product has been
mentioned clearly in the text and also indicated on "Literature" in the last chapter
of this thesis.

ABSTRACT
DEDY DAMHUDY. Coral Reef Health Condition based on Herbivorous Fish
Density in Pulau Tiga Subdistrict, Natuna District. Under direction of M. MUKHLIS
KAMAL, and YUNIZAR ERNAWATI
The research was conducted in Pdau Tiga Subdistrict, Natuna District, Riau
islands Province from April to August 2009. Pulau Tiga is an area dominated by a
sea area with marine resource potential, particularly coral reefs. Around the area
of coral reefs, fishing activities have been canied out intensively by fishermen
using explosives Oombs) and toxic (potassium). Consequently, aquatic
ecosystems have been exploited, take time to make a natural recovery in order to
maintain and restore the quality and quantity of available resources. Especially for
coral reef ecosystem, one of the factors that influence the resilience rate is the
availability of hard substrate in a bottom waters as a settlement for coral larvae.
Herbivorous animal has a major influence in determining the rate of coral reef
animal larval settlement on a substrate because it can prevent the occurrence of a
macro-algae excessive closure of hard substrate. This study was aimed to know
the relationship between the conditions of the abundance of herbivorous fish with
coral reef recovery rate. The methods used were the square transect for
determining the condition of coral reefs, growth of juvenile corals and algae cover
(DCA), whereas for the determination of herbivorous fish community structure

using modification of Line Intercept Transect (LIT), Quadrat Method (QM) and
Underwater Fish Visual Census (UVC). The analysis used was standard
ecological analysis, correlation test, linier regression and multivariate analysis to
find the relationship between the abundance of herbivorous fish, algae (DCA) and
coral reefs. The results showed that coral reefs ecosystem in the area are still in
good condition with live coral cover average of 63.17%, and shown an indication
of an increase in the percentage of coral cover which previously R5%.The result
of multivariate analysis can be stated that the higher the abundance of herbivorous
fish, then live coral cover and growth of juvenile corals increasing, and decreasing
algae cover on coral reef ecosystems. The results of correlation test, multivariate
analysis and linear regression (t-Student test), show that from 24 species of
herbivorous fish recorded then obtained three species of herbivorous fish that play
a role in herbivory in stabilizing coral reefs ecosystem in Pulau Tiga Subdistrict,
they are Chlorurus microrhinos, Scarus rivulatus and Siganus doliatus.
Keywords: herbivorous Jish, herbivoly, DCA (dead coral with algae), coral reef
health, coral growth, Pulau Tiga

SUMMARY
DEDY DAMHUDY. Coral Reef Health Condition based on Herbivorous Fish
Density in Pulau Tiga Subdistrict, Natuna District. Under direction of M. MUKHLIS

KAMAL, and YONIZAR ERNAWATI.
Pulau Tiga as one of subdistricts in Natuna District is the area dominated
by sea areas with very potential marine resource, especially coral reef. Around the
coral reefs areas, fishing activities have been carried out intensively by fishermen
using explosives (bombs) and toxic (potassium). Consequently, aquatic
ecosystems have been exploited at the area, take time to make natural recovery in
order to maintain and restore the quality and quantity of available resources.
Especially for coral reef ecosystem, one of the factor that influence the resilience
rate is the availability of hard substrate in a bottom waters as a settlement for coral
larvae.
Herbivorous animal has a major influence in determining the rate of coral
reef animal larval settlement on a substrate because it can prevent the occurrence
of a macro-algae excessive closure of hard substrate. Among herbivorous fish,
three families are considered as the indicator of marine ecosystem health, namely
Siganidae, Scaridae, and Acanthuridae.
The aim of this study is determining the abundance and diversity of
herbivorous fish species, determining the relationship between benthic structure
and fish community structure (non-herbivorous and herbivorous reef fish),
determining the relationship between the conditions of herbivorous fish species
abundance with coral reef resilience level, and formulating recommendations for

development of coral reef ecosystem management base on ecology in an
integrated and sustainable. The results of this study would be an expected as
reference in development of sustainable management of coral reef ecology and
reef fish and the concept of sustainable fishing to local fishemen.
The research was conducted in Pulau Tiga Subdistrict waters, Natuna
District of Riau Kepulauan Province. Time of research implementation was
carried out during five months from April to August 2009.
Data collection method that used in the research is survey method for
collecting primary data, and desk study for secondary data. The method used for
determining coral reefs condition, growth of juvenile corals and algae cover
(DCA) was square transect (Quadrat Method) with quotation of observation area
width of 10 m x 10 m, modified by line intercept fransect (LIT) method along 70
meters parallel with coastline. Observation of corals was also measured to
determine growth rate of new coral (recruitment) with calculating the spread ofnew
coral colonies from species of Acropora spp. (diameters ranged fiom 1 to 30 cm).
Whereas for the determination of herbivorous fish c o m d t y structure was used
modification of Line Intercept Transect (LIT), Quadrat Method (QM) and
Underwater Fish Visual Census (UVC).
The analysis used was qualitatively and quantitatively, i.e. standard
ecological analysis, correlation test, linier regression and multivariate analysis to

find the relationship between the abundance of herbivorous fish, algae (DCA) and
coral reefs.

The results showed that the lowest percent coverage was in site 1 which
included in the location of relatively disturbed area (40.48%), and the highest
percent coverage at site 3 that included in the location of relatively undisturbed
area (74.07%) with percent cover average of 63.17% or in "good" category.
Growth of juvenile coral colonies was obtained the average of diameter length of
the colony ranged from 16.00 to 17.26 cm with a percent coverage ranged from
2.772% to 4.250% and the average number of colonies per transect (100 m-2)
ranged from 100 to 200 colonies. Conversely, the highest algae (DCA) cover was
found in site 1 (34.830%) and the lowest at site 3 (13.279%).
The number of herbivorous fish species obtained during the study was
amounted to 24 species. Individuals of herbivorous fish recorded was amounted to
203 individuals, with the total average of abundance of herbivorous fish in the
entire sites of 1,450 individuals per hectare or 5.01% of the total abundance of
reef fish, the highest abundance was Scaridae (864 individuals ham')or 57.35%,
followed by Siganidae (350 individuals haM')or 23.22%, and Acanthuridae (236
individuals ha-') or 15.64%.
The result of multivariate analysis of the relationship between herbivorous

fish abundance, coral reef and alga cover (DCA) showed that algae negatively
correlated to the abundance of herbivorous fish, live coral cover and juvenile coral
growth. Meanwhile, based on results of correlation test, linear regression and
multivariate analysis were selected three species of fish that have a significant
relationship of the abundance to live coral cover with the positive correlation, i.e.
C. microrhinos (Gm (2.813)> tmb(2.228), P = 0.018), S. rivulatus (& (2.418)> t a
(2.228), P = 0.036), and S. doliatus (h, (3.846p t* (2.228), P = 0.003). Then, the
abundance of three species of fish also has a significant relationship to the algae
cover (DCA) with a negative correlation, i.e. C. microrhinos (5bt (2.288)> Lb
(2.228), P = 0.045), S. rivulatus (& (2.349)> t* (2.228), P = 0.041) and S. doliatus
(&, (2.813)> t* (2.228), P = 0.018). Implication for coral reef management in
Pulau Tiga Subdistrict may be done with a few steps of strategy, which include:
a) prohibition of destructive fishing practices, b) maintain water quality that
supports the health and growth of coral reef, c) maintain and improve the
abundance and diversity of herbivorous fishes, d) prohibition of taking the live
coral and dead coral, and, e) environmental engineering.
Keywords: herbivorous fuh, herbivory, DCA (dead coral with algae), coral reef
health, coral growth, Pulau Tiga

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CORAL REEF HEALTH CONDITION
BASED ON HERBIVOROUS FISH DENSITY
IN PULAU TIGA SUBDISTRICT,
NATUNA DISTRICT

DEDY DAMHUDY

Thesis
As one of the requirement for the degree of
Master of Science in
Study Program of Coastal and Marine Resources Management Science

POST GRADUATE SCHOOL
BOGOR AGRICULTURAL UNIVERSITY
BOGOR
2009

Title

: Coral Reef Health Condition based on Herbivorous Fish

Density in Pulau Tiga Subdistrict, Natuna District
Name

: Dedy Damhudy

SRN

: C252070304

Approved by

Advisory Board

Dr. Ir. M. Mukhlis Kamal M.Sc
Supervisor

Dr. Ir. Yunizar Ernawati, MS
Co-Supervisor

Acknowledged by

Head of Study Program
of Coastal and Marine Resources
Management Science

'---

>

Prof Dr. Ir. Mennofatria Boer, DEA

Date of Examination: November 12'~,2009

Approved on:

1 1, DEC

2m

PREFACE
Thanks to God Almighty (Allah S.W.T) for all blessing and guidance, thus
the Thesis with entitled "Coral Reef Health Condition based on Herbivorous
Fish Density in Pulau Tiga Subdistrict, Natuna District" has been successfully

completed. This Thesis is as one of requirement on Post Graduate title
acomplishment on Study Program of Coastal and Marine Resources Management
Science -Post Graduate School, Bogor Agriculture University.

I would like to thanks to all parties who have provided assistance, support
and guidance to all the time, especially:
1. Dr. 11. M. Mukhlis Kamal, M.Sc. as Supervisor and Dr. Ir. Yunizar Ernawati,

MS as Co-Supervisor who has devoted much time and thought for their
direction and suggestion during the writing period.
2. Prof. Dr. Ir. Khairil Anwar Notodiputro, M.S as Dean of Post Graduate

School, Bogor Agriculture University and staff and Prof. Dr. Ir. Mennofatria
Boer, DEA as Head of Study Program of Coastal and Marine Resources
Management Science who have given maximum administrative services.

3. Ministry of Marine Affairs and Fisheries Republic of Indonesia, which has
initiated educational program at Post Graduate School by Coral Reef
Rehabilitation and Management Program - Phase I1 (COREMAP 11-ADB),
during this two years.
4. Drs. H. Daeng Rusnadi, M.Si as Head of Natuna Regency who has given the

o p p o h t y for me to participate in educational program at Post Graduate
School during this two years.
5. My dearest Father (Harsono) and Mother (Supiah) who always giving

support, interest and prayer for me.

6. My dearest Wife (Eka Risanti), and my lovely Children (Fathur Andyka
Putra, Aqillah Dewanti and M Wahyudyka Nurashri) who give me the
motivation, patience and prayer during this educational program.
7. My Old-Brother (Joko Setyo, S.Pi) who has given moral and spiritual supports

to me, and my Old-Sister (Sri Rezeki), my young sisters (Widi Hastuti
Ningsih, SE and Rahayu Siti Hasanah) for your prayer.

8. All colleagues (Mas ArieJ; Dodon, Jojo, Ichal, ni and Mu 'in) for tremendous
support and contribution during the research.
9. My colleagues in Coastal and Marine Resources Management Program 2007,
Sandwich Program COREMAP I1 DKP (Amehr Hakim, Ahmad Jaelani, Budi
Hartono, Cici Kurniawati, Dedy Eka Syaputra, Dini, Endar Maraskuranto,
Febrizal, Hadi Suryanto, Harlim Maharbakti, Hemat Sirait, Ilham, Jimmy,
Jusak Wiraharja, Lida Aro Ndhuru, M. Riza Kurnia Lubis, Partini,
Raymundus Ngajo, Simon Sinaga, Syarviddint Alustco, Tenny Apriliani,
Tema Aro Ndhuru, Wan Irham, Zulfkar).
10. My best-friend as my brothers; l h m as a travelling and studying companion
in the spiritual path of Islam, and Hemat Sirait who always together and
provides happiness in the integrity of friendship.
I realize that this Thesis is still found any imperfection. Therefore, I
welcome constructive suggestion and recommendation from various persons.
Hopefully this Thesis can give sense and benefit to the reader.

Bogor, November 2009

Dedy Damhudy

CURRICULUM VITAE
Dedy Damhudy was born in Tanjungpinang, Riau Kepulauan Province at
December 31S', 2009 with Harsono as father and Supiah as mother. He is the third
child of five children.
In 1994, I graduated from Senior High School (SMUN 1) of
Tanjungpinang and did my baclielor degree at Department of Aquatic Resources
Management, Riau University, Pekanbaru and graduated in 1999.

I have been working for Marine and Fisheries Services (DKP), Natuna
Regency since 2002. In 2007, I have had an opportunity to continue the education
at Post Graduate School, Bogor Agricultural University, Study Program of
Coastal and Marine Resources Management Science.

TABLE OF CONTENTS
Page
LIST OF TABLES................................................................................... xiii
LIST OF FIGURES .....................................................................

xiv

LIST OF APPENDICES....................................................................................

xvi

1 INTRODUCTION
1.1 Background.......................................................................
1.2 Problem Statement...................................................................
1.3 Objectives and Purpose........................................................
1.4 Logical Framework .............................................................
2 LITERATURE REVIEW
2.1 Coral Reef .........................................................................
2.1.1 Biology of Coral...........................................................
2.1.2 Characteristics of Coral Reef ............................................
2.1.3 Threat, Limitation Factors of Growth and Phase Shift of

..

2.1.4 Coral Reef Resilience....................................................................
2.2 Characteristic of algae in coral reef ecosystem......................................
2.3 Characteristicof Herbivorous Fish as Reef Fish...........................
2.4 Relationship between Herbivorous Fish Community, Coral Reef and
Algae......................................................................................................
3 MATERIALS AND METHODS
3.1 Time and Location....................................................................
3.2 Material and Tools.............................................................
3.3 Data Collection.....................................................................
3.3.1 Primary Data.................................................................................
3.3.2 Secondary Data.............................................................................
3.4 Data Analysis.........................................................................................
4 STUDY AREA OVERVIEW . .
4.1 Local Geographical Condition..............................................................
4.2 Social and Demographic Condition.......................................................
4.3 Community Local Wisdom....................................................................
4.4 Description of Research Location and Site............................................
5 RESULTS AND DISCUSSION
5.1 Coral. Reef
. Health Rate based on Waters Physical and Chemical
Condiaon................................................................................................
5.2 Coral Reef Health Rate based on Benthic Cover...................................
5.2.1 Coral Reef Ecosystem...................................................................
5.2.2 Growth of Juvenile Coral..............................................................
5.2.3 Percent Coverage of Algae (DCA)...............................................

1
3
4
4
6
6
S

10

xii
5.3 Coral Reef Health Rate based on Fish Community Structure...............
5.3.1 Composition of Species and Family of Reef Fishes.....................
5.3.2 Density of Species and Family of Herbivorous Fish....................
5.3.3 The Presence Relative Frequency of Herbivorous Fish
Species..........................................................................................
5.3.4 Diversity, Evenness and Dominance of Herbivorous Fish...........
5.4Relationship between Benthic Structure and Fish Community
Structure.................................................................................................
5.4.1 Benthic Structure of Coral Reef Ecosystem.................................
5.4.2 Fish Community Structure (Non-Herbivorous and Herbivorous
Reef Fishes)...................................................................................
5.5 Relationship between Herbivorous Fish Density, Coral Reef and
Algae Cover (DCA)...............................................................................
5.6 Implication for Coral Reef Management...............................................
6 CONCLUSION AND RECOMMENDATION
6.1 Conclusion............................................................................................
6.2 Recommendation...................................................................................

78
78

REFERENCES...........................................................................

SO

APPENDICES............................................................................

90

LIST OF TABLES
Page

1 Criteria of coral reef assessment based on percent coral coverage
(Gomez and Yap 1988)................................................................. 30
2

Water quality in the average (or meanksd) which measured of each
sites of research in Pulau Tiga Subdistrict............................................... 43

3 Number and percent coverage of growth of juvenile coral colonies
51
from genus of Acropora at each site in study site...................................
4 Six species with the highest reef fish density in study sites.................... 57
5

6

The highest value of presence relative frequency of herbivorous fish
species of the whole observation site in study site..................................

62

Correlation and t-student test between density of herbivorous fish
species, percent live coral coverage and algae cover @CA)
(n=12)......................................................................................................

72

xiii

LIST OF FIG

S
Page

The flow chart of research framework.. .......................................

5

Map of study site........................................................................25
Scheme of square transect plot placement in line intercept transect
(English et al. 1994)............................................................................... 27
Scheme of transect and underwater fish visual census of herbivorous
fishes (English et al. 1994).............................................................. 28
Photo of waters location in each research sites: (a) site 1 (ST-1); @) site
2 (ST-2); (c) site 3 (ST-3); and (d) site 4 (ST-4) ...................................... 38
Mean of percent benthic coverage of biota and substrate categories in
the study sites ............................................................................... 44
Variation of benthic substrate structure of biotic categorize and other
biota (a) and abiotic @) in study site....................................................... 45
Percent live coral coverage at each observation sites in study
site.............................................................................................................
46
Some corals species of genus Acropora, Porifes and Montipora in study
site............................................................................................................. 48
Values of diversity index (H'),evenness index Q and dominance
index (C) of coral reef at each observation sites in study
site............................................................................................................. 50
Average of percent coverage of growth of juvenile coral colonies from
genus of Acropora at each site in study site.............................................. 52
Several lifeform of growth of juvenile coral colonies from genus of
Acropora (colonies diameter of 1- 30 cm) in study site........................... 53
Percent cover of dead cord with algae @CA) at each site in study
site.............................................................................................................
55
Number of forms of dead coral with algae (DCA) were found in study
site.. ........................................................................................................... 56
Values of diversity index (H'), Evenness index Q and dominance
index (C) of overall
reef
.
. fishes (non-herbivorous and herbivorous) at 58
each observation sltes m study site..........................................................
Density and dominance of fish from family of Pomacentridae that
found in study site..................................................................................... 59
Percent average of herbivorous fish of the whole observation sites in
study site................................................................................................... 61

xiv

Some of herbivorous fish species h m the family of Scaridae,
Acanthuridae, and Siganidae with the highest presence relative
frequency in study site.............................................................................. 62
Values of diversity index (H'), evenness index (E) and dominance
index (C) of herbivorous fish at each observation sites in study
site.......................................................................................................... 63
The dendrogram of cluster analysis of biota and substrate characteristic
in study site. (T = transect, ST = site).................................................. 64
MDS of biota and substrate characteristic in study site. (T=transect,
ST=site, Cl=cluster 1, C2=cluster 2, C3=cluster 3)................................. 65
PCA-plot of biota and substrate category in study site. (T=transect,
ST=site)................................................................................................ 66
The dendrogram of cluster analysis based on individual number of reef
fish families (non-herbivorous and herbivorous) in study site.
(T =transect, ST=site)............................................................................... 67
MDS of fish distribution based on individual number of reef fish
families (non-herbivorous and herbivorous) in study site. (T=transect,
ST=site. C1=cluster 1. C2=cluster 2. C3=cluster 3, C4=cluster
PCA-plot of fish distribution based on individual number of reef fish
family (non-herbivorous and herbivorous) in study site. (T=transect,
ST=site)..................................................................................................... 69
The graph of correlation between herbivorous fish density (Ks) toward
live coral cover (LC), junile coral growth (CJ), and algae
(DCA)........................................................................................................ 71
The graph of correlation between density of herbivorous fish species
(C. microrhinos, S. rivulatus and S. dolintus) to live coral cover
(LC),
juvenile
coral
growth
(CJ)
and
algae
(DCA) ............................................................................ 73

LIST OF APPE1\TI)ICES
Page
Number of coral species at each study site............................................

91

Percent coral coverage of each genus in study site................................ 93
Percent cover of biota and substrate at study site..................................

96

Species number (S), individuaI number 0,diversity index (H3,
evenness index (E) and dominance index (C) of coral reef at each site
in study site............................................................................................

97

Growth of juvenile coral colonies at site 1............................................

98

Growth of juvenile coral colonies at site 2 ............................................

99

Growth ofjuvenile coral colonies at site 3............................................ 100
Growth of juvenile coral colonies at site 4 ............................................ 101
Density of species and family of overall reef fishes in study
site.................................................................................................... 102
Species number (S), individual number 0,
diversity index (H'),
evenness index Q and dominance index (C) of overall reef fishes in
study site............................................................................................ 105
diversity index (H'),
Species number (S), individual number 0,
evenness index Q and dominance index (C) of herbivorous fish in
study site.............................................................................................. 106
Correlation and PCA between Percent Live Coral Coverage (LC),
dead coral with algae (DCA), juvenile coral (CJ) and herbivorous
fish (Ks)................................................................................................ 107
Correlation and PCA between percent live coral coverage (LC), dead
coral with algae (DCA), juvenile coral (CJ) and herbivorous fish (Ks)
&om species of C. mirrorhinos, S. rivulatm and
108
S. doliatus..............................................................................................
Lmear regression between percent live coral coverage (Y1) and DCA
(Yz)of herbivorous fish species (C. microrhinos (Xi), S. rivulafus
(X,), and S. doliatus (X3))...................................................................... 109
Example of coral species diversity inside 1 (one) squae transect
with measurement of l m x l m was obtained from underwater
camera in study site.............................................................................

xvi

112

1 INTRODUCTION
1.1 Background

Coral reef ecosystem as one of coastal area ecosystem has a very
important role, both ecologically and economically. The former, coral reef
ecosystem is an area of various associated organisms providing nursery ground,
feeding ground and spawning ground. The latter, it is as a potential fishing
ground, especially for traditional fishermen.
Generally, coral reef ecosystem is very sensitive to environmental impacts
related to human activity on coastal and marine areas. Human impacts, direct and
indirect, have been recognized as a higher threat than the natural disturbances.
The major causes of coral reef degradation in Indonesia are blast fishing, sewage,
industrial pollution and cyanide fishing (Suharsono 1998).
Pulau Tiga as one of subdistricts in Natuna District is the area dominated
by sea areas with very potential marine resource, especially coral reef. Around the
coral reefs areas, fishing activities have been carried out intensively by fishermen
using explosives (bombs) and toxic (potassium). The exertion of the bomb had
been long enough since 1970s, but had almost no longer exists since 2007.
Meanwhile, the use of potassium began to develop in early 1990s. Destructive and
poisonous fishing has been banned since 2007 as the area was selected to be the
COREMAP site.
Nowadays, in the context of community life in Pulau Tiga Subdistrict,
sustainability of community economic activities will be greatly affected by the
waters ecosystem health condition because most of populations are concentrated
in coastal areas and their livelihood depend on the results of marine resources,
particularly fishermen. Consequently, aquatic ecosystems have been exploited at
the area, take time to make natural recovery in order to maintain and restore the
quality and quantity of available resources.
One indication of a good ecosystem health is coral reef ecosystem
resilience rate, explicitly the ability of an ecosystem to recover from a damaged
condition to be better (Salm 2002). Resilience rate of coral reef ecosystem is one
important indication to the manager in well and right managing coral reef

ecosystem. This information is usually needed in assessing vulnerable rate of
coral reef &om disturbances and estimate the length of the process of restoration
and rehabilitation of coral reefs ecosystem (Grimsditch & Salm 2006), especially
for coral reef ecosystem, one of the factor that influence the resilience rate is the
availability of hard substrate in a bottom waters as a settlement for coral larvae
(Grimsditch & Salm 2006; Salm 2002).
Herbivorous animal has a major influence in determining the rate of coral
reef animal larval settlement on a substrate because it can prevent the occurrence
of a macro-algae excessive closure of hard substrate. This excessive closure can
inhibit coral animal larval settlement on the substrate which in turn will reduce the
ability of coral reefs to recover soon. Herbivorous fish feed on a variety of macroalgae, therefore substrates will always be in clean condition (Marshal &
Schuttenberg 2006).
Four groups of the main herbivorous fish that live in Indonesia coral reefs
are the

family of Pomacentridae (damseljsh),

Siganidae (rabbitfish),

Acanthuridae (surgeonzsh) and Scaridae (parroflsh). In many tropical areas,
these fish families cover 15-25% of the biomass and diversity of coral species
(Tomascik 1997).
Among herbivorous fish, three families are considered as the indicator of
marine ecosystem health, namely Siganidae, Scaridae, and Acanthuridae (Russ
1984a). In this fish indicates 35-90% composition of diet is algae (Ferreira &
Goncalves 2006). In Lizard Island, Great Barrier Reef, and surrounding, the
abundance of three major herbivorous fish, respectively Achanthuridae (54%),
Scaridae (31%) and Siganidae (14%) (Meekan and Choat 1997). Example of
Siganidae is Siganus spp., Scaridae (Scarus spp.), and Acanthuridae (Acanthurus
spp.). Those Siganids have relatively high economic value.
Thus, to determine coral reef ecosystem health will require a study to
notice the condition of abundance and composition of groups of herbivorous fish
species. Indirectly, the condition can be a bioindicator of coral reef ecosystem
health when viewed from recovery rate in Pulau Tiga Subdistrict.

1.2 Problem Statement
Pulau Tiga is one of subdistricts formed from the expansion of the
Bunguran Barat Subdistrict, Natuna District in 2006. In these areas the coastal
waters have the potential resources of coral reefs, which supporting to
surrounding community livelihood. Iluman activities that utilize aquatic resources
by destructive fishing has lasted a long time still exists even today, and has put
pressures and disturbances of its existence, especially the health of coral reefs.
Coral reefs are under pressure and disturbance will create natural
resilience to restore ecosystem functions. The ability of coral reef to perform the
recovery process must be maintained by a variety of ecological factors. One of
these factors is biological factors, especially herbivorous fish. Herbivorous fish is
indicated for health as bio-indicator of reef health also has an economic value.
This phenomenon is an issue for local government and community as
stakeholders to be more serious in managing coral reef resources, because the
recovery rate of coral reef ecosystem is a vulnerability level assessment of
disturbance and the basic for management of coral reef ecosystem.
According to the facts above, subsequently the main problems in this
research are:
1. Dependence of community of Pulau Tiga Subdistrict to coral reef resource

existence as supporting community livelihood.

2. Utilization of aquatic resources by destructive fishing practices which affecting
coral reef health.

3. Existence of reef fishes, especially herbivorous fish indicated as bio-indicator
of reef health even have economic value and tends to decrease.
4. Management of coral reef ecosystem that have not been directed due to lack of

seriousness by the stakeholders in the region.
There are many aspects related to marine ecosystem health problems,
associated with the presence of herbivorous fishes. However, in this study, the
problem is limited and defined in terms of question, as follows: "How is the
prospect of coral reef health and resilience level if viewed from the conditions of
density and community structure of herbivorous fishes in Pulau Tiga Subdistrict
waters, Natuna District?"

1.3 Objectives and Purposes
The aim of this study is:
1. Determining the abundance and diversity of herbivorous fish species.
2. Determining the relationship between benthic structure and fish community

structure (non-herbivorous and herbivorous reef fish).

3. Determining the relationship between the conditions of herbivorous fish
species abundance with coral reef resilience level.
4. Formulating recommendations for development of coral reef ecosystem
management base on ecology in an integrated and sustainable.
The results of this study would be an expected as reference in development
of sustainable management of coral reef ecology and reef fish and the concept of
sustainable fishing to local fishermen.
1.4 Logical Framework

Ecologically, relationship between coral reef and herbivorous fish are
supporting each other in the food chain. If stress occurs to coral reef, then it will
affect to herbivorous fish and vice versa.
Basically, there is a strong dynamic between the dynamic presence of
herbivorous fish, macro-algae cover, and coral larvae settlement in the substrate
(Albert et al. 2007). The relationship is consistent as long as measured from the
same habitat type (Russ 1984). Coral animal larvae and macro-algae are
competing to obtain a suitable substrate for their life. Nevertheless, the presence
of herbivorous fish in a certain amount will lead competition victory more of coral
animal larvae (Sluka & Miller 2001). On the basis of these ideas, then the
recovery rate of coral reef ecosystem assessed based on approach the condition of
herbivorous fish abundance.
Conditions of herbivorous fish abundant will reduce macro-algae percent
coverage in a hard substrate because of its existence likely will be grazed by
herbivorous fish. It will provide the opportunity to coral animal larvae add to
settlement rate in suitable substrate. This condition will facilitate a coral reef
ecosyste~nto recover itself if damaged.

Hence, it is necessary to manage the development pattern of coral reef and
the relation to reef fish ecologically, so that the balance between conservationbased utilization of ecosystem can be maintained.
CORAL REEF
ECOSYSTEM

t
Water Quality

C o n d k n ofNon Hedi~omus
and Habivomur; Fih

Coral Reef Condition

t

I Percent of Hard Subsink that Covered I
by Mimalgae and M a c m a b
Growth of Jwenii

/

Relabyhip Rate

t
Reskrce of Coml Reef Ecosystem

Figure 1 The flow chart of research framework

I

2 LITERATURE REVIEW
2.1 Coral Reef
2.1.1 Biology of Coral

Corals are the animals belong to Phylum Coelenterate (Goreau el al.
1982). Corals consist of polyps that can live in colony and solitary. According to
Boaden and Seed (1985) the corals component comprise: coral skeleton, coral
animal, and zooxhantellae. These components have the interaction between one
coral to another. Likewise, the change of coral animal biomass (polyp) is
determined by the availability of zooxanthellae photosystesis product (quality and
quantity). While, the presence of zooxanthellae is affected by amount of nutrients
or C02can be reciprocal translocation by coral animal and zooxanthellae.
Coral polyps are composed of soft part and hard part shaped calcareous
skeleton. The mouth is at the top that also functions as an anus. Food is digested
by the mesenterial filaments and leftovers out through the mouth. Coral tissue
composed of ectoderm, mesoglia and endoderm. Ectoderm is the outer tissue and
equipped with cilia, the mucus and a number of nematocyst. Mesoglia is a tissue
that lies between the ectoderm and endoderm, shaped like jelly. Endoderm is the
innermost tissue and contains most of zooxanthellae (Nybakken 1997; Suharsono
1984). The formation of coral skeleton is generally interpreted as an increase in
calcareous skeleton mass of corals, where the live tissue of coral animals covered
by a skeleton composed of calcium carbonate in the form of aragonite (CaC03
crystal fibers) and calcite (a common crystal form of CaC03) (Goreau et al.
1982).
Coral skeleton is structured of calcium carbonate (CaC03) which is
secreted by the epidermis in the middle below the polyp. Secretion process
produces a calcareous skeleton as cup-shaped which settled polyp. A cup is
known as the calyx; wall surrounding called theka; floor of the cup is called the
basal-plate). On the floor occured a septa made of a calcareous radiating septa.
Besides functionate as a place of polyps, skeleton (shell) also provides a shelter
(Barnes 1980).

According to Goreau (1959), Calcification increases with decreasing
concentration of C 9 due to photosynthesis activity of zooxanthellae and
influence of carbonic anhidrase enzymes. Reduced C02 will increase the value of
acidity level (pH) becomes more alkaline and thus more easy precipitation of
calcium carbonate. Calcium ions are actively transported by the calcium
bicarbonate through gastrodermis and combined with bicarbonate ions. At first,
forming the dissolved calcium bicarbonate then formed eksoskeleton crystal of
CaC03.
Coral performed both sexual and asexual reproduction. Asexual
reproduction can occur by fragmentation, the release of polyp from the skeleton
and asexual production of larvae. Such reproduction is limited geographically by
the origin of coral, lifeform of colony and growth. In sexual reproduction, gamete
cells will be settled to the mesenterials that usually occurs in every year, seasonal,
monthly or uncertain time. In hermaphrodite or gonochoris coral, spawning events
may take place through external fertilization while the brooding can occurs
through internal fertilazation, both will produce planula which is teleplanic or
philopatric (Veron 1995).
Planula that had been released, will swim toward the light, then swim back
to the bottom, if favorable conditions, they will be attached and form a new
colony. The colonies become sexually mature at the minimum size. Massive coral
of Favia dor-eyensis has sexually mature at 8-years-old colony with a diameter of
10 cm. Some of the branching corals like species of Acropora, Pocillipora, and
Stylophora, reach sexual maturity at a younger age (Barnes & Hughes 1999).
Lifeform of stony coral generally a reflection of the surrounding
environmental condition, morphological plasticity provides an o p p o b t y for
coral reef to local adaptation. For example, species of branching corals with a slim
form generally found in areas with low wave energy, coral colonies in areas with
concentrations of low light, generally sprawl or is shaped like a tubulate, and
many coral reefs in turbid areas have a lifeform more vertical (upward) compared
to the flat lifeform (Riegl 1996).

2.1.2 Characteristics of Coral Reef

Coral reef is a colony of solid formation and composed of solid sediment
skeleton of benthic organisms that live in warm sea waters with a depth of
sufficient light, is formed on physiographic construction of tropical waters, and
mainly consists of calcareous skeleton constructed by a hermatypic coral building
reef (Levinton 1988). Reef or calcareous benthic building is a combination of the
all numbers of biota that are continuous binding of calcium and carbonate ions
from seawater to produce a skeleton (Odum 1971). Then Nybakken (1997) stated
that the reefs are essentially massive deposits of calcium carbonate produced
primarily by corals (phylum Cnidaria, class Anthozoa, order Madreporaria

=

Scleractinia) with minor additions from calcareous algae and other organisms that
secrete calcium carbonate.
Coral has some significance, but usually only a general name given to the
order Scleractinia, which the components have a hard calcareous skeleton. Order
scleractinia divided into 2 (two) building groups i.e. reef building and non-reef
building. In the first group known as hermatypic that needed sunlight for survival,
and the second group as ahermatypik, normally, the life does not depend on
sunlight (Veron 1986). The distinguishing feature between the two is that most
hermatypic corals have in their tissues small symbiotic (living together) plant cells
called zooxanthellae, whereas most ahermatypic corals do not have these cells.
Furthermore, hermatypic corals are those that produce reefs, while ahermatypic
corals do not form reefs (Nybakken 1997).
Coral reefs are an ecosystem in a tropical sea that have a high productivity
(Sukarno et al. 1983), the productivity amount of coral reef due to the recycIing of
nutrients through biological processes (Longhurs & Pauly 1987).
Based on lifeform, coral is classified into two groups specifically, stony
coral and soft coral. Stony coral is the common name of the order Scleractinia
which has a hard calcareous skeleton, and is the most important structure in
building reef and red algae, which functions in the growth of the physical
structure of coral reefs, especially for coral reefs facing the sea. While soft coral
better known as Alcyonaria is one of the Coelenterata has an important role in the
physical formation of coral reefs. With a soft body and sturdy, Alcyonaria body is

limber and not easily broken. Alcyonaria flabby body, but is supported by a large
number of the spines that sturdy, small in size, arranged in such a way that the
flexible body Alcyonaria and not easily broken. These spines contain calcium
carbonate called spicula (Manuputty 1986).
Based on the type, coral reef can be classified into three categories
(Sukarno et al. 1983; Nontji 1993; Nybakken 1997), explicitly:

1. Atoll: this coral reef form is a circle like a ring, around the lagoon with depth
between 40 to 100 meters, as well as the barrier reef, atoll can be lived on the
maximum depth of coral reefs which coral reef can still be alive.

2. Fringing Reef ov Shore Reej this coral reef lies on the coastline and reaches
depths of less than 40 meters. Fine growth of this reef is in the areas with large
waves, with growth upwards the surface (vertical) and to the open seaward
(horizontal), this coral reef is almost not found on the coast which has many
wide rivers.
3. Barrier Reej This coral reef is located some distance from the coast, separated
by lagoon with a depth that reaches 40 to 70 meters, this coral reef is generally
elongated shape along the coastline as if such a barrier.
Furthermore, according to Sukarno (1993) stated that coral reef
ecosystems can be found basically three kinds of the floor surface which is a
zonation of coral reef ecosystems are:
1. ReefFlat: The floor surface shape of coral reef with flat in the shallow waters

is more influenced by tides and waves of seawater, so that these habitats have
a variety of environmental condition and very large fluctuated. In the tidal
condition, many parts suffer from drought and the type of coastal coral reef
gets a lot of sediment influence, fresh water and the additional nutrient from
the ground from the land.
2. Reef Slope: the floor surface form that sloping can be divided into two reef

slopes. Reef slope with slant to a deeper area, out of reef flat towards the open
sea is called fore reefslope and reef slope towards the lagoon is called back

reef slope or lagoon slope. The state of fore reef slope is opened facing the
wave and opened sea, while the slope of lagoon fairly protected from the
onslaught of the waves because of the reef flat. Nybakken (1997) states that at

a depth of 15-20 m to surface, coral growth is lush and diverse, dominated by
the branching arms of the Acropora.
3. Lagoon Floor or Sub-Marine-Terrace:form of floor surface that flat in a deep
area has more varied condition than at the lagoon floor which is usually the
area of sediment. The floor of sub-marine-terrrace that shallow is a coral reef
community or benthic community that solid when sufficient of current and
waves that can prevent the accumulating organism brought from shallow water
areas. According to Nybakken (1997), that condition inside the lagoon, with the
small wave and circulation, and greater sediment is not good for coral growth.
Lagoon floor is more overgrown by seaweed (Thalassia, Cynodocea), or green
algae such as Caulerpa and Halimeda.
2.1.3 Threat, Limiting Factors of Growth and Phase Shift of Coral

Causes of coral reef damage are classified into three parts, specifically: (1)
coral damage by biological causes such as the existence of competition, predation,
explosion of phytoplankton population, (2) coral damage by mechanism causes
such as the existence of strong current, sedimentation, volcanism activities,
changes in temperature and salinity, and sunlight penetration, (3) coral damage to
human activities such as oil pollution, chemicals, taking the stony coral for
industrial purposes and building, bombing, a collection of biota and etc.
(Soeharsono 1990).
Illegal fishing with homemade bombs or dynamite is rampant throughout
Southeast Asia and has devastated many coral reefs in the region. In addition to
fish and other organisms being indiscriminately killed, coral skeletons are
shattered by the blasts, leaving fields of broken rubble. This rubble shifts in the
current, abrading or burying any new coral recruits, thereby slowing or preventing
reef recovery (Fox et al. 2003).
Corals 'bleach' (i.e. go pale or snowy-white) as a result of a variety of
stresses, both natural and human-induced, which cause the degeneration and loss
of the coloured zooxanthellae from their tissues. Under normal conditions,
zooxanthellae numbers may fluctuate seasonally as corals adjust to fluctuations in
the environment (Brown el al. 1999; Fitt et al. 2000). Bleaching may even be a

regular feature in some areas. During a bleaching event, corals may lose 60 - 90%
of their zooxanthellae, and the remaining zooxanthellae may lose 50-80% of their
photosynthetic pigments (Glynn, 1996). Once the source of stress is removed,
affected corals may recover, with zooxanthellae levels returning to normal, but
this depends on the duration and severity of the environmental disturbance
(Hoegh-Guldberg, 1999). Prolonged exposure can lead to partial or complete
death of not only individual colonies but also large tracts of coral reef.
Bleaching can also occur in non-reef building organisms such as soft
corals, anemones and certain species of giant clam (Tridacna spp.), which also
have symbiotic algae in their tissues. As with corals, these organisms may also die
if the conditions leading to bleaching are sufficiently severe (Westmacott et al. 2000).
Reefs that are aIready under stress from human activities may be more
susceptible to bleaching when HotSpots develop, since weakened corals may lack
the capacity to cope with the additional stress of increased sea surface
temperature. Furthermore, even after SSTs return to normal, humaninduced
stressful conditions may inhibit the settlement and growth of new corals. Indeed,
reefs that have already been exposed to persistent human disturbances often show
a poor ability to recover (Brown, 1997). On the other hand, a reef that is not
stressed by human activities may have a greater chance of recovery, as
environmental conditions will he closer to those optimal for coral settlement and
growth.
Physical environment play a role in determining the composition of the
coral community, while the biological environment play a role in shaping species
richness. The diversity can occur only after attainment a series of ecological
balance; not only the balance between the coral organisms, but also between the
coral with other organisms, including predator and parasite, and also between
other organisms that have a direct relationship with coral, such as the balance
between herbivorous fishes and macroalgae (Veron 1986).
Temperature is an important parameter of aquatic environment. Increase or
decrease in water temperature due to the powerplant activity which was built
inshore, has brought damage to the coral reef community. Temperature rise of 3 5OC above threshold causes decreased the ability of coral to live and grow

(Suharsono 1990). Optimum temperature of coral growth in the tropical area is 25
-

30°C, extreme temperature wi