Fish Communities As Related to Substrate Characteristics in the Coral Reefs of Kepulauan Seribu Marine National Park, Indonesia

Fish communities as related to substrate characteristics in the coral reefs of Kepulauan Seribu Marine National Park, Indonesia, five years after stopping blast fishing practices

Dissertation zur Erlangung des Doktorgrades der Naturwissenschaften – Dr.rer.nat. im Fachbereich 2 (Biologie/Chemie) der Universität Bremen

vorgelegt von Unggul Aktani

angefertigt am Zentrum für Marine Tropenökologie Bremen 2003

Gutachter der Dissertation : 1. Gutachter: Prof. Dr. Matthias Wolff 2. Gutachter: Dr. Andreas Kunzmann

Tag des öffentlichen Kolloqiums : 15 Mai 2003 Erratum

Erratum to: “AKTANI, U. 2003. Fish communities as related to substrate characteristics in the coral reefs of Kepulauan Seribu Marine National Park, Indonesia, five years after stopping blast fishing practices”

A list of corrections follows:

Page iv. Line 6-7 from above should be:

Chaetodon octofasciatus was abundant in areas dominated by Acropora corals. Chromis analis was abundant in areas dominated by sub-massive corals and other fauna.

Page iv. Line 11 from above should be:

… the current zoning management can not be considered an adequate tool to achieve this purpose.

Page 84. Line 11-12 from above should be:

C. octofasciatus is more abundant in area dominated by Acropora corals. C. analis is more abundant in areas dominated by sub-massive corals and other fauna. SUMMARY

AKTANI, U. 2003. Fish communities as related to substrate characteristics in the coral reefs of Kepulauan Seribu Marine National Park, Indonesia, five years after stopping blast fishing practices

Kepulauan Seribu (“Thousand Islands”) is an archipelago of 110 small islands in the southwest Java Sea. The archipelago is currently used for traditional fishing area, tourism, sand mining, off shore oil exploration, sailing, and conservation. The major problem in Kepulauan Seribu was blast fishing since the 1970’s, which had caused extensive coral destruction. Blast fishing stopped since 1995 when the Kepulauan Seribu Marine National Park was founded (since 1982 there was a nature reserve).

Six islands were chosen, each with three permanent transects (at 4-5 m depth) on the northeast parts of each island, covering three management zones: Bira and Putri (Sanctuary Zone), Genteng and Melinjo (Intensive Utilization Zone), and Pandan and Opak (Traditional Utilization Zone). From October 2000 until August 2001, underwater visual censuses were carried out within 45 day-intervals. The fish transects were 50 × 5 m. Within the fish transects, underwater sequential photographs were taken (50 × 1 m) to assess benthic groups and coral reef coverage. Classification of the substrate type was based on benthic groups and life form categories.

Hard coral coverage was 43, 29, 25, 20, 18 and 7 % in Genteng, Pandan, Melinjo, Bira, Opak and Putri, respectively. Dead corals were the dominant cover in all islands surveyed (range: 52 to 83 %). The long-lasting impact of blast fishing on the substrate was reflected by the presence of extensive fields of dead coral rubble (range: 31 to 59 %). In contrast to the zoning allocation, the percent hard coral cover in the Sanctuary Zone was lowest and percent cover of dead coral was highest. The highest cover of hard coral was found in the Intensive Utilization Zone.

A total of 119 fish species belonging to 25 families (32 863 fishes) were determined. Pomacentridae was the most abundant family (range: 53 to 62 %), followed by Labridae (27 to 33 %). Planktivore (28 to 40 %) and omnivore (27 to 37 %) fish were the two most abundant trophic groups. The composition of the fish community changed seasonally according to the alteration of west and east monsoon; with seasonal shifts in both the fish species composition and fish abundances. During the

iii west monsoon, Chromis atripectoralis and Halichoeres argus, while during the east monsoon Pomacentrus lepidogenys, P. alexanderae and Cirrhilabrus cyanopleura were abundant, respectively. The fish community was more related to the presence of benthic groups and life form categories than to the coverage of hard corals. Pomacentrus lepidogenys was abundant at encrusting corals. Pomacentrus alexanderae was abundant at mushroom and dead corals. Chaetodon octofasciatus and Chromis analis were abundant in areas dominated by Acropora corals. Benthic feeders and omnivores preferred substrate with high cover of dead corals. Planktivores preferred foliose corals.

Since the goal of the national park management is maintenance of a high coverage of hard coral and a high diversity fish community, the current zoning management can be considered an adequate tool to achieve this purpose. The results highly suggest a re-zoning of the national park and should encourage the management to intensify both surveillance frequency and law enforcement for the entire national park.

iv ZUSAMMENFASSUNG

AKTANI, U. 2003. Fischgemeinschaften und ihr Bezug zu Substrat-Charakter- istika in den Korallenriffen vom Kepulauan Seribu Marine National Park, Indonesien, fünf Jahre nach dem Einstellen der Dynamitfischerei

Kepulauan Seribu (“Tausend Inseln”) ist ein Archipel mit 110 kleinen Inseln in der südwestlichen Javasee. Das Archipel wird zur Zeit genutzt für traditionelle Fischereigebiet, Tourismus, Sandabbau, Off-shore Ölförderung sowie den Naturschutz. Das Hauptproblem in Kepulauan Seribu war seit den siebziger Jahren die Dynamitfischerei, die in grossen Bereichen zur Zerstörung der Korallenriffe geführt hatte. Die Dynamitfischerei ist seit 1995 eingestellt, als der Kepulauan Seribu National Park gegründet wurde.

Sechs Inseln wurden ausgewählt, die in drei Managementzonen liegen: Bira und Putri (Kernzone), Gentang und Melinjo (Intensive Nutzungszone), sowie Pandan und Opak (Traditionelle Nutzungszone). An der Nordostseite jeder Insel wurden drei Dauertransekte in 4-5 m Wassertiefe festgelegt. Von Oktober 2000 bis August 2001 wurden dort alle 45 Tage visuelle Fischzählungen durchgeführt. Die Fischtransekte maßen 50 × 5 m. Innerhalb der Fischtransekte wurde das Substrat fotografiert (50 × 1 m), um den Deckungsgrad an benthischen Gruppen und an Korallen zu quantifizieren. Die Substrattyp-Klassifizierung basierte auf benthischen Gruppen und „life form categories“.

Der Deckungsgrad mit Hartkorallen in Gentang, Pandan, Melinjo, Bira, Opak und Putri betrug jeweils 43, 29, 25, 20, 18 und 7 %. Tote Korallen waren die dominante Bedeckung auf allen untersuchten Inseln (zwischen 52 und 83 %). Weite Flächen mit Korallenschutt (31 bis 59 %) spiegeln den bleibenden Einfluss der Dynamitfischerei auf das Substratgefüge wieder. Im Widerspruch zum höchsten Schutzstatus der Kernzone wurde dort der geringste Deckungsgrad an Hartkorallen und der höchste Grad an Bedeckung mit toten Korallen gefunden.

Insgesamt wurden 119 Fischarten aus 25 Familien nachgewiesen (32 863 Fische). Pomacentridae stellten die häufigste Familie (53 bis 62 %), gefolgt von Labridae (27 bis 33 %). Planktivore (28 bis 40 %) und omnivore (27 bis 37 %) Fischarten waren

v die beiden häufigsten trophischen Gruppen. Die Zusammensetzung der Fischgemeinschaft veränderte sich saisonal entsprechend dem Wechsel zwischen West- und Ostmonsun, mit Verschiebungen sowohl in der Fischartenzusammensetzung als auch in den Fischabundanzen. Während des Westmonsuns waren Chromis atripectoralis und Halichoeres argus und während des Ostmonsuns Pomacentrus lepidogenys, P. alexanderae und Cirrhilabrus cyanopleura häufige Arten. Die Fischgemeinschaft stand eher im Bezug zu der Anwesenheit benthischer Gruppen und „life form categories“ als zum Deckungsgrad mit Hartkorallen. Pomacentrus lepidogenys war häufig mit Krustenkorallen vergesellschaftet. Pomacentrus alexanderae wurde häufig an pilzförmigen Korallen und an toten Korallen angetroffen. Chaetodon octofasciatus und Chromis analis waren in Bereichen häufig, die von Acropora-Korallen dominiert wurden. Fische, die ihre Nahrung am Boden finden und omnivore Fische bevorzugten Substrat mit einem hohen Anteil an toten Korallen. Planktivore bevorzugten den Aufenhalt in der Nähe von trichterförmigen Korallen.

Da der Erhalt eines hohen Deckungsgrades mit Hartkorallen und einer Fischgemeinschaft mit grosser Diversität erklärte Aufgabe des Nationalpark- Managements ist, kann die aktuelle Zonierung nicht als ein adäquates Instrument zum Erreichen dieser Ziele angesehen werden. Die Ergebnisse weisen deutlich auf die Notwendigkeit einer Re-Zonierung des Nationalparkes hin und sollten das Management dazu ermutigen, sowohl die Überwachung vor Ort als auch die Vollstreckung geltender Gesetze für den gesamten Nationalpark zu verstärken.

vi RINGKASAN

AKTANI, U. 2003. Komunitas ikan dan keadaan substrat terumbu karang di Taman Nasional Laut Kepulauan Seribu, Indonesia, setelah lima tahun tidak terjadi penangkapan ikan dengan bahan peledak

Kepulauan Seribu terdiri dari 110 buah pulau kecil di Laut Jawa bagian barat daya. Di kepulauan ini terdapat kegiatan wilayah penangkapan ikan tradisional, pariwisata, pengambilan karang/pasir, penambangan minyak lepas pantai, pelayaran dan perlindungan alam. Sejak tahun 1970-an permasalahan utama di Kepulauan Seribu adalah penangkapan ikan dengan menggunakan bahan peledak yang mengakibatkan kerusakan hebat terumbu karang. Penangkapan ikan dengan bahan peledak tidak terjadi lagi sejak 1995 ketika kawasan tersebut dijadikan Taman Nasional (sejak 1982 sudah menjadi kawasan cagar alam).

Enam pulau di tiga zona pengelolaan yang berbeda dipilih sebagai lokasi penelitian, masing-masing dengan tiga tempat pengamatan tetap (di kedalaman 4-5 m) pada bagian timur laut pulau: Bira dan Putri (Zona Inti), Genteng dan Melinjo (Zona Pemanfaatan Tradisional), Pandan dan Opak (Zona Pemanfaatan Trdisional). Sejak bulan October 2000 sampai Agustus 2001, dilakukan pencacahan bawah air terhadap komunitas ikan. Transek untuk pencacahan ikan berukuran 50 × 5 m. Di dalam transek tersebut dilakukan pemotretan substrat terumbu karang secara berkesinambungan sepanjang 50 × 1 m. Pengelompokan substrat terumbu didasarkan pada jenis substrat dan bentuk terumbu karang.

Luas penutupan karang hidup di Genteng, Pandan, Melinjo, Bira, Opak dan Putri berturut-turut adalah: 43, 29, 25, 20 dan 7 %. Jumlah penutupan karang mati adalah paling luas diantara jenis substrat yang lain (berkisar dari 52 – 83 %). Dampak jangka panjang kegiatan pengangkapan ikan dengan bahan peledak ditandai oleh banyaknya luasan puing terumbu yang masih tampak (31 – 59 %). Hasil yang mengejutkan adalah rendahnya luas penutupan karang hidup dan tingginya luas penutupan karang mati di Zona Inti. Luas penutupan karang hidup tertinggi terdapat di Zona Pemanfaatan Intensif.

vii Jumlah ikan yang tercatat sebanyak 32863 ekor yang termasuk kedalam 119 species dan 25 family. Pomacentridae merupakan family yang paling melimpah (53 – 62 %), diikuti oleh Labridae (27 – 33 %). Planktivora (28 – 40 %) dan omnivora (27 – 37 %) merupakan kelompok pemakan yang terbanyak. Komposisi komunitas ikan, dalam hal ini species dan kelimpahan, berubah sesuai perubahan musim barat dan timur. Selama musim barat species yang melimpah adalah Chromis atripectoralis dan Halichoeres argus, sedangkan pada musim timur yang paling melimpah adalah Pomacentrus lepidogenys dan Cirrhilabrus cyanopleura. Komunitas ikan lebih terkait terhadap jenis substrat dan bentuk karang dibandingkan dengan luas penutupan karang hidup. Pomacentrus lepidogenys melimpah pada karang ‘encrusting’. Chaetodon octofasciatus dan Cromis analis melimpah di tempat yang banyak terdapat koral jenis Acropora. Ikan pemakan hewan dasar dan omnivora menyukai substrat karang mati. Planktivora menyukai karang ‘foliose’.

Tujuan pengelolaan taman nasional adalah menjaga tingginya penutupan terumbu karang dan tingginya keragaman ikan, namun berdasarkan hasil peneltian memperlihatkan bahwa pengelolaan yang ada belum bisa mencapai tujuan tersebut. Saran yang bisa diajukan adalah melakukan penataan kembali zonasi yang ada dan pihak pengelola melakukan peningkatan pengawasan di lapang dan penegakan hukum.

viii ACKNOWLEDGMENTS

I would like to thank to German Academic Exchange Service (DAAD). This study would not have been possible without the scholarship from DAAD.

Many people made this work possible and I would like to express my gratitude to all of them. I am most grateful to Prof. Dr. Matthias Wolff, who supervised and supported my work, for suggestions and the critical revision to work out essential results of my work. I am most thankful to Dr. Andreas Kunzmann who supervised me, for many fruitful discussions, and who has been patients, understanding and supportive through the whole period of my work. The late Prof. Dr. H.M. Eidman, who has gave supports and many valuable criticisms during preparation of my work.

I deeply appreciate to Dr. Iris Kötter, who gave valuable comments and corrections in the earlier versions of my manuscript and also for her friendship and encouragements. Deeply thankful to Uwe Krumme for many fruitful discussions, valuable comments and who many times helps me to translate many letter to German, including the summary of this dissertation and suggestion to rethink about the title.

I wish my gratitude to Center for Tropical Marine Ecology (ZMT) that gave best facilities to do my work. Special thanks for Prof. G. Hempel, Prof. V. Ittekkot, Prof. U. Saint-Paul and Dr. Werner Ekau.

My grateful also for Tilman Appermann and Dr. Marc Kochcius for valuable comments.

I thank to authority of the Kepulauan Seribu Marine National Park who gave me permission to do the field study, especially Drs. Achmad Abdullah, Ir. Andi Rusandi and Ibu Nena. The field work would have been impossible without help from Rangers of the marine park, especially: Pak Teguh and his family for preparing the food and accommodation; Pak Sairan, Pak Nelson and Pak Henry as diving buddy and for their enthusiasms and help me on all field surveys; Pak Riyad and Pak Daeng for accompanying me in many surveys; Pak Zakaria for diving equipments; Pak Salim, Pak Syarif, Pak Sokeh, Pendi, and Sigit. Thank you to Pak Mujar for the boat. Thank you Kak Jony for driving me to Muara Angke.

My special thanks go to Dr. Mark Wunch, Dr. Claudio Richter, Gaby Boehme, Christa Müller, Sabine Kadler, Dr. Sabine Dittmann, Silke Meyerholz, Andreas Hanning, Matthias Birkicht, Dr. Carlos Jimenez, Dr. Gesche Krause, Iris Freytag, Jenny, Fernano Porto, Inga Nordhause, Kerstin Kober, Dr. Uta Berger, Dr. Marion Glasser, Kai Bergmann, Dr. Chriastiane Snack, Dr. Daniela Unger, Dieter Peterke, Dr. Tim Jennerjahn, Dr. Petra Westhaus-Ekau, Dr. Joko Samiaji, Dr. Rubén Lara, Natalie Loick, Uschi Stoll, Uschi Werner, Cristiane Hueerkamp, Ario, Auck, Eugene, and Mukhlis for encouragements and friendships over the last years.

Many thanks for Jochen Scheuer who lent us many things. Many thank also to Wazir for maintenance of our underwater camera. For Dini and Yus Rustandi, thank you very much for the map.

I am very thankful for my parents who gave me a chance to have a good education even in many social and economic difficulties. And also thanks for our big family that supports my education.

The last but not least, many thanks for my wife, Mia, for the patient and who give me many supports, encourage and love. And for our children, Lala and Dhika, who gave me inspirations.

ix TABLE OF CONTENTS

SUMMARY iii ZUSAMMENFASSUNG v RINGKASAN vii ACKNOWLEDGMENTS ix LIST OF FIGURES xii LIST OF TABLES xv LIST OF APPENDICES xv

1. INTRODUCTION ...... 1

1.1. CORAL REEFS AND FISHES ...... 1

1.2. REEF FISHERIES ...... ……...... 3

1.3. KEPULAUAN SERIBU (THOUSAND ISLANDS) – STUDY SITE ...... 6

1.4. HYPOTHESES ...... …………….. 11

1.5. OBJECTIVES OF THE STUDY...... 11

1.6. METHODOLOGICAL APPROACH.……………………………………….. 12

2. MATERIAL AND METHODS ...... …. 14

2.1. THE STUDY AREA ...... 14

2.2. SAMPLING SITES ...... 15

2.3. TIME FRAME OF STUDY ...... …...... 17

2.4. PERMANENT TRANSECTS ...... 17

2.5. CORAL SAMPLING ...... 18

2.6. REEF FISH SAMPLING ...... 20

2.7. DATA ANALYSES .…………...... 21

3. RESULTS …………………………………………………………………... 31

3.1. FEATURES OF THE BENTHIC HABITAT.……….…….………………….. 31

3.2. PATTERN OF MAJOR BENTHIC GROUPS AND LIFE FORM CATEGORIES.… 35

3.3. REEF FISH COMMUNITY.….…………………………………………… 37

3.4. FISH DIVERSITY ………………………………………………………. 47

3.5. FISH SPECIES-ABUNDANCE RELATIONSHIP MODEL.……………………. 49

3.6. FISH COMMUNITY STRUCTURE.……………………………………….. 57

3.7. RELATING BENTHIC HABITAT WITH FISH COMMUNITY STRUCTURE …… 61

4. DISCUSSION ……………………………………………………………….. 68

4.1. VARIATION IN CORAL REEF COVERAGE ALONG THE GRADIENT OF BLAST FISHING IMPACT ……………………………………………… 68 4.2. VARIATION IN FISH COMMUNITY ALONG THE GRADIENT OF BLAST FISHING IMPACT …………………………………………………….. 72

x 4.3. SEASONAL CHANGES IN THE FISH COMMUNITY STRUCTURE.………… 79

4.4. VARIATION IN FISH DIVERSITY WITHIN THE ZONING MANAGEMENT…... 80

4.5. METHODOLOGICAL ASPECTS ………………………………………... 81

4.5.1. ASSESSMENT OF LIFE FORM CATEGORIES AND BENTHIC GROUPS …… 81

4.5.2. FISH VISUAL CENSUS.……………………………………………….. 82

5. CONCLUSIONS AND OUTLOOK……………………………….……………... 84

5.1. CONCLUSIONS ………………………………………………………... 84

5.2. OUTLOOK……………………………………………………………... 85

6. REFERENCES ………………………………………………………………. 86

APPENDICES.……………………………………………………………….. 94

xi LIST OF FIGURES

FIGURE 1.1. Kepulauan Seribu Marine National Park (bordered by dash line) – the study area. 7

FIGURE 1.2. The zoning management of Kepulauan Seribu Marine National Park. ………….. 10

FIGURE 2.1. The study sites were located in Kepulauan Seribu Marine National Park. Insets are the six selected islands with three sampling sites at each island. ………….…. 16

FIGURE 2.2. The tetra-pod frame for photography coral coverage (modification from English et al. 1994). ………………………………………………………………………. 19

FIGURE 2.3. Observer swims along the 50-m permanent transect at 0.5 m above the substratum to visually census the reef fish (English et al. 1994). ……………….. 21

FIGURE 2.4. The process of the multivariate analysis (modified from Field et al. 1982). (CA: cluster analysis, PCA: principle component analysis, NMDS: non-metric multidimensional scaling). ……………………………………………………….. 30

FIGURE 3.1. Percent cover of the benthic groups: hard corals, dead corals, other fauna and algae. (The sequence of the islands was based on the zoning management: the Sanctuary Zone (Bira and Putri), the Intensive Utilization Zone (Melinjo and Genteng) and the Traditional Utilization Zone (Opak and Pandan)). ……...….…. 32

FIGURE 3.2. Percent cover of Acropora life form categories: Acropora Branching (ACB), Acropora Digitate (ACD) and Acropora Tabulate (ACT)...... 33

FIGURE 3.3. Percent cover of Non-Acropora life form categories, consisting of: Coral Sub- massive (CS), Coral Foliose (CF), Coral Branching (CB), and Coral Encrusting (CE). …………………………………………...... 33

FIGURE 3.4. Percent cover of dead coral in each island, consisting of: rubble dead corals (DCR), massive dead corals (DCM), and dead corals with algae (DCA)...... 34

FIGURE 3.5. Average percentage of the number of colonies for all hard coral categories...... 34

FIGURE 3.6. The hierarchal dendrogram of all components of benthic groups and life form categories produced by group average linkage displayed a tendency to separate the islands into three groups at 77 % similarity level (dash and dot line) and into two groups of geographical position: West and East side of the islands (solid line), without Opak (dash line)...... 35

FIGURE 3.7. NMDS plot of all components of benthic groups and life form categories...... 36

FIGURE 3.8. The PCA-biplot of benthic and life form categories...... 37

FIGURE 3.9. Abundance of the most abundant fish families at the different study sites during the study time: October 2000 (a), March 2001 (b), April 2001 (c), June 2001 (d), August 2001 (e). Data were pooled from all sites in each island...... 40

FIGURE 3.10. Abundance of the most abundant fish families during the time of the study. Data were pooled from all sites in each island...... 41

FIGURE 3.11. Abundance of the different trophic groups at each study sites during the time of study: October 2000 (a), March 2001 (b), April 2001 (c), June 2001 (d), and August 2001 (e)...... 42

FIGURE 3.12. Abundance of different trophic fish groups during the time of the study. Data were pooled from all islands...... 43

xii

FIGURE 3.13. Number of fish species censused from Pandan (a), Opak (b), Bira (c), Putri (d), Melinjo (e) and Genteng (f) with three sites each from October 2000 - August 2001. Solid triangle with solid line indicates the pooled (from 3 sites per island) number of species. Solid circle with dash line indicates the mean number of species (n = 3 sites per island, ± SE)...... 44

FIGURE 3.14. Rank abundance plot (a) and linear regression analysis of fish abundance (b) in Pandan (the linear relationship is highly significant, P<0.01). Sampling time was in October 2000, March 2001, April 2001, June 2001 and August 2001. The table shows the ten most abundant species. R2 = coefficient of determination...... 50

FIGURE 3.15. Rank abundance plot (a) and linear regression analysis of fish abundance (b) in Opak (the linear relationship is highly significant, P<0.01). Sampling time was in October 2000, March 2001, April 2001, June 2001 and August 2001. The table shows the ten most abundant species. R2 = coefficient of determination. 51 ......

FIGURE 3.16. Rank abundance plot (a) and linear regression analysis of fish abundance (b) in Bira (the linear relationship is highly significant, P<0.01). Sampling time was in October2000, March 2001, April 2001, June 2001 and August 2001. The table shows the ten most abundant species. R2 = coefficient of determination...... 52

FIGURE 3.17. Rank abundance plot (a) and linear regression analysis of fish abundance (b) in Putri (the linear relationship is highly significant, P<0.01). Sampling time was in October 2000, March 2001, April 2001, June 2001 and August 2001. The table shows the ten most abundant species. R2 = coefficient of determination...... 53

FIGURE 3.18. Rank abundance plot (a) and linear regression analysis of fish abundance (b) in Melinjo (the linear relationship is highly significant, P<0.01). Sampling time was in October 2000, March 2001, April 2001, June 2001 and August 2001. The table shows the ten most abundant species. R2 = coefficient of determination...... 54

FIGURE 3.19. Rank abundance plot (a) and linear regression analysis of fish abundance (b) in Genteng (the linear relationship is highly significant, P<0.01). Sampling time was in October 2000, March 2001, April 2001, June 2001 and August 2001. The table shows the ten most abundant species. R2 = coefficient of determination...... 55

FIGURE 3.20. Rank abundance plot (a) and linear regression analysis of fish abundance (b) in all islands (the linear relationship is highly significant, P<0.01). Sampling time was in October 2000, March 2001, April 2001, June 2001 and August 2001. The table shows the ten most abundant species. R2 = coefficient of determination...... 56

FIGURE 3.21. Dendrogram of hierarchical clustering with group linkage methods of the fish community, based on species abundance. Three replicate samples were made from each island at each sampling. (A=Pandan, B=Opak, C=Bira, D=Putri, E=Melinjo, F=Genteng)...... 58

FIGURE 3.22. Non-metric multidimensional scaling ordination of the fish community based on species abundance. Three replicate samples were made for each island at each sampling. (A=Pandan, B=Opak, C=Bira, D=Putri, E=Melinjo, F=Genteng). …... 58

FIGURE 3.23. PCA-plot of the fish community based on species abundance. Three replicate samples were made for each island at each sampling. (A=Pandan, B=Opak, C=Bira, D=Putri, E=Melinjo, F=Genteng). ……………………………………… 59

FIGURE 3.24. PCA-biplot of trophic group of fish produced by SVD method. The sampling times were October 2000 and March, April, June, and August 2001. (A=Pandan, B=Opak, C=Bira, D=Putri, E=Melinjo, F=Genteng). ……………………………. 60

xiii FIGURE 3.25. CCA-triplot of the distribution of selected fish-species found during October 2000-August 2001 in six islands: fish species (solid circle), life form and benthic variables (hollow circle), and the islands (solid square). The benthic variables were: Acropora Branching (ACB), Acropora Digitate (ACD), Acropora Tabulate (ACT), Coral Branching (CB), Coral Encrusting (CE), Coral Foliose (CF), Coral Massive (CM), Coral Sub-massive (CS), Mushroom Coral (CMR), Millepora (CME), Heliopora (CHL), Other Fauna (OT), Algae (AL), and Dead Coral (DC). The fish species were Chaetodon octofasciatus (Ctoc), Chromis analis (Cran), Pomacentrus alexanderae (Pmal), and Pomacentrus lepidogenys (Pmle). The sampling times were October 2000 (Oc), and March (Ma), April (Ap), June (Ju) and August 2001 (Au). …………………………………………... 62

FIGURE 3.26. CCA-triplot of the distribution of selected fish-species found during October 2000-August 2001 in six islands: fish species (solid circle), life form and benthic variables (hollow circle), and the islands (solid square). An arrow (dash line) was projected along the Acropora Branching variable that indicating a gradient; the perpendicular dash line in the arrow indicated the position of the islands along this gradient. (Refer to Figure 3.25 for abbreviations).……………………. 63

FIGURE 3.27. CCA-triplot of most abundant of fish-families from October 2000-August 2001 in six islands: fish families (solid circle), life form and benthic variables (hollow circle), and the islands (solid triangle). The benthic variables were: Acropora Branching (ACB), Acropora Digitate (ACD), Acropora Tabulate (ACT), Coral Branching (CB), Coral Encrusting (CE), Coral Foliose (CF), Coral Massive (CM), Coral Sub-massive (CS), Mushroom Coral (CMR), Millepora (CME), Heliopora (CHL), Other Fauna (OT), Algae (AL), and Dead Coral (DC). The fish families were: Pomacentridae (Poc), Labridae (Pmal), Scaridae (Sca), Chaetodontidae (Cha) and Nemipteridae (Nem). The sampling times were October 2000 (Oc), and March (Ma), April (Ap), June (Ju) and August 2001 (Au). ……………………………………………………………………………... 65

FIGURE 3.28. CCA-triplot of trophic groups of fish found from October 2000-August 2001 in six islands: fish families (solid circle), life form and benthic variables (hollow circle), and the islands (solid triangle). The benthic variables were: Acropora Branching (ACB), Acropora Digitate (ACD), Acropora Tabulate (ACT), Coral Branching (CB), Coral Encrusting (CE), Coral Foliose (CF), Coral Massive (CM), Coral Sub-massive (CS), Mushroom Coral (CMR), Millepora (CME), Heliopora (CHL), Other Fauna (OT), Algae (AL), and Dead Coral (DC). Trophic groups of fish: herbivore (H), omnivore (O), planktivore (P), detritivore (D), benthic feeder (B), coralivore (C) and piscivore (Pi). The sampling times were October 2000 (Oc), and March (Ma), April (Ap), June (Ju) and August 2001 (Au). . ………………………………………………………………………. 67

xiv LIST OF TABLES

TABLE 2.1. The geographical-position of sampling sites in each island...... ………………… 17

TABLE 3.1. Complete list of fish families and species according to systematic order produced by visual census method in all surveyed islands. ………………………………… 39

TABLE 3.2. The diversity of fishes calculated by using some diversity formulas (A), and the distribution model of fish species abundance in each island and for all islands together (B). The χ2 test is used to describe the goodness-of-fit of the distribution model with P<0.05. The percent value in brackets indicates the probability of the observed data to be the same as the expected distribution model. …..…………….. 46

TABLE 3.3. The Comparison of the Shannon diversity index (H') between the islands in the core zone (P. KA Bira and P. Putri Timur) and outside the core zone from each sampling time. The t-test was run at a significance level of P<0.001 (n.s.= Not significantly different; s. = Significantly different). …………………...…………... 47

TABLE 3.4. Comparison of Shannon diversity index (H') between the sampling times in all islands. The t-test was performed at a significance level of P<0.001 (n.s. = Not significantly different; s. = Significantly different). . ………………………….…... 48

LIST OF APPENDICES

Appendix 1. Complete list of the percent cover of the major benthic groups and life form categories (%) at the different study sites. ………………………………………... 94

Appendix 2. Number of coral colonies differentiated by their growth form at the study sites assuming that coral growth is 2.4 mm per month and in circular direction, S=small (< 651 cm2; growth during five years), M=medium (651 - 940 cm2; growth during six years) and L=large (> 940 cm2; growth during seven or more years) (van Moorsel 1988). ………………………………………………………. 95

Appendix 3. Complete list of fish species according to their systematic order and their abundances at each site throughout the study period. ……………………………. 96

Appendix 4. Trophic group of all fish species observed (Sources: Lieske & Myers 1997; Fish Base www.fishbase.org).………………………………………………………….. 100

1. INTRODUCTION

1.1. CORAL REEFS AND REEF FISHES

At least 794 species of scleractinian corals are known to build coral reefs

(Spalding et al. 2001). As biogenic structures, coral reefs constitute highly fragmented habitats that are defined both by physical structure and the organisms associated with them, including fishes and many invertebrates (Rosen 1984, Hubbard

1988, Choat & Bellwood 1991, Spalding et al. 2001).

The distribution and abundance of the coral reef fish community is strongly influenced by biological and physical factors like wave exposure, sediment loads, water depth as well as topographical complexity (rugosity) of the coral reef substrate

(e.g. Risk 1972, Luckhurst & Luckhurst 1978a, Carpenter et al. 1981, Williams 1982,

Bell & Galzin 1984, Sano et al. 1984, Galzin et al. 1994, McClanahan 1994,

Chabanet et al. 1997). Additionally, weather and currents were found to influence reef fish community composition (Walsh 1983). Within a given family of reef fish, ecological parameters like the coverage of living Scleractinian corals, food diversity and reproductive behavior seem to affect the diversity of reef fishes (Galzin et al.

1994). However, according to Jennings & Polunin (1997), a single dominant process rarely governs the structure of reef fish communities. Therefore, the general opinion is that reef fish abundance and diversity are correlated with the complexity and health of the coral reef habitat.

More than 4,000 species of teleost fish, representing about 18 % of the total number of fishes, can be found in coral reefs (Choat & Bellwood 1991, Lieske &

Myers 1994, Spalding et al. 2001). According to Bellwood (1996 & 1998) it is hard to define the fish living on coral reefs as “reef fish”, since “reef fish” families are

1 characteristic for coral reefs but their distribution are usually not restricted to them.

Therefore, it is not surprising that there are no fish families that are only restricted to the coral rich region (Robertson 1998).

Choat & Bellwood (1991), however, found a number of fishes with a characteristic appearance and morphology that are almost always associated with coral reefs and achieve their highest abundance on them. The assemblages and distribution of fishes on coral reefs vary greatly among habitat patches and the complex architecture of the reef building corals (Choat & Bellwood 1991). As biogenic structures corals depend on their physical and biological environment and the interaction between biological and geological processes (Choat & Bellwood 1991,

Sale 1991, Williams 1991). Hence, Bellwood (1998) defines reef fishes as those species that live on coral reefs and Robertson (1998) as the fish species that live on consolidated substrata that form coral and inorganic reefs.

Two different theories about reef fish assemblages have been proposed: according to the “order/deterministic” theory, reef fish have evolved specific habitat requirements that reduce competition for limited resources and thereby enables the coexistence of a great number of specialized species (Smith 1977). By contrast the

“chaos/stochastic” theory or “lottery” hypothesis postulates that reef fish assemblages are highly variable and unpredictable over time (Sale 1974). Studies supporting one or the other theory can be found. For example Greene & Shenker (1993) found that the fish assemblages appeared to be extremely stable over the two-year period of their investigation. The series studies from Sale (1974, 1975, 1976, 1982) supported the chaos theory, albeit he derived the theory from coexistence in territorial behavior of pomacentrid fishes in which each individual defended a small permanent territory for

2 food, shelter and nests sites. However, according to Bohnsack (1983) both theories are valid for coral reef fish communities.

1.2. REEF FISHERIES

Coral reef fishes are mainly small and sedentary throughout most parts of their lives (Sale 1991). However, they are important resources on coral reefs (Russ 1991), contributing about 9 % of the total fish biomass in the World Oceans (Sorokin 1995) or 7 % of the marine fish captured worldwide (Russ 1991). Coral reef fishery is an important livelihood, particularly in developing countries (Munro & Williams 1985,

McManus 1997) and is typically a multi-species and multi-gear fishery (Spalding et al

2001).

Russ (1991) gave a comprehensive review about the effects of fishing on coral reefs. According to his findings (that is hoped to be reinforced by the proposed thesis), fishing activities cause habitat modification, thereby affecting fish populations and communities’ level of reef fishes. Intensive fishing can cause large-scale and long-term damage of coral coverage or structural heterogeneity of the benthic substratum, and hence significantly affects reef fish communities. Destructive fishing techniques have clearly negative impacts on reef fish communities (Russ & Alcala

1989, Saila et al. 1993). Munro & Williams (1985) stated that significant fishing pressure can change the age and size structure of fish populations, decrease the stock sizes and may change the community structure within a coral reef.

The blast fishing technique was introduced in the Indonesian Archipelago after

World War II as an easy way to catch schooling fish (Pet-Soede & Erdmann 1998).

The explosives are usually home made; often using glass bottles filled with a mixture of agricultural fertilizer and kerosene, although dynamite is sometimes used as well

(Pet-Soede & Erdmann 1998; Spalding et al. 2001). The fishermen throw the bomb

3 by hand toward the reef, where it explodes on the water surface or within the water body (Pet-Soede & Erdmann 1998). Even though Indonesian law prohibits blast fishing, it is still common throughout the archipelago, particularly in remote areas where the law enforcement is weak (Pet-Soede et al. 2000, UNESCO 2000). Besides the ecological damage blast fishing also caused considerable economic losses to the

Indonesian society (Pet-Soede et al. 2000). This method kills both targeted (such as dense schools of Siganids and Caesionids) and non-targeted fish, as well as invertebrates (Pet-Soede & Erdmann 1998). However, the taxonomic and yield composition of blast fishing varied highly (Fox & Erdmann 2000). Blast fishing also damaged or destroyed the reef habitat and caused fields of coral rubble when the same reef area was bombed several times (Pet-Soede & Erdmann 1998).

Blast fishing is considered one of the most destructive anthropogenic threats to coral reefs, as not only the target fish, but also almost all organisms within the blast radius get killed (McManus 1997, Pet-Soede et al. 1999, Fox et al. 2001). Destructive fishing practices have reduced the productivity of coral reefs around the world

(Spalding et al. 2001) and led to a substantial reduction in cover of live coral and an increase of dead coral rubble (Russ & Alcala 1989). This increase may attract fish species, which are specialized in feeding on or settling onto coral rubble or both, e.g.

Labridae (Russ & Alcala 1989, Aktani 1990).

Recovery of the reef structure from a single blast may take years or decades

(Spalding et al. 2001). McManus et al. (1997) predicted that every year approximately 1.4 % of the coral cover in the Philippines is lost due to blast fishing and calculated that a reduction of fishing effort by approximately 60 % is required to gain an optimal resource use and to solve the over-fishing problem due to blast fishing activities. Riegl & Luke (1998) also found significant changes in coral and fish

4 community composition of blasted sites. Bombed or anchor-damaged coral reefs in

Indonesia are around 50% less diverse in shallow water as compared to undamaged areas (Edinger et al. 1998).

Although coral reefs are of great ecological and economic importance, little is known how coral reefs respond to human destructive fishing activities. Particularly the process of recovery and natural regeneration of the coral reef itself and associated animals lacks detailed studies (Saila et al. 1993, Riegl & Luke 1998, Hodgson 1999,

Fox et al. 2001). Furthermore, the understanding of the diversity of live, the complexity of ecological interactions and the structures and patterns within coral reefs is still limited (Sale 1976, Smith 1977, Hodgson 1999, Spalding et al. 2001).

Kaufman (1983) found that the destruction of reef fish habitats was followed by changes in predator abundance, herbivore feeding behavior, and the distribution of territorial damselfishes. Sano et al. (1984) observed that the destruction of hermatypic corals led to changes in fish community structure resulting from a change of food resources and the decrease in structural complexity of coral colonies.

Herbivore fishes, zooplankton feeders and omnivores were significantly more abundant and of higher species richness on the living coral colonies than on damaged coral colonies; or vice versa: when the structural complexity of the coral reef decreased due to bio- and physical-erosion, the diversity and abundance of resident reef fishes decreased as well. Bell & Galzin (1984) stated that the presence and amount of live coral cover may be more important in structuring fish communities than previously thought.

5 1.3. KEPULAUAN SERIBU (THOUSAND ISLANDS) – STUDY SITE

Kepulauan Seribu (Thousand Islands) is an archipelago that is located in the southwest Java Sea or just northwest of Jakarta Bay (Fig. 1.1). It consists of 110 vegetated islands that stretch around 80 km from northwest to southeast and 30 km from east to west. The southernmost reefs are located around 25 km northwest of

Jakarta Bay and are separated by a deep channel from Java Island (Ongkosongo &

Sukarno 1986, Tomascik et al. 1997). The islands are generally smaller than 10 ha and their altitude is less than 3 m above sea level. The archipelago is used for tourism, sand mining, off shore oil exploration, sailing, and conservation (UNESCO

2000). For many years, the major problem in Kepulauan Seribu was blast fishing, which caused coral degradation (Hutomo 1987, Sukarno 1987).

Most of the ecological studies from Kepulauan Seribu are about the coral reefs, but only few deals with reef fishes. According to Suharsono et al. (1998) at least 132 fish species belonging to 24 families can be found in Kepulauan Seribu. Hutomo &

Adrim (1986) observed that the diversity and abundance of fishes in Kepulauan

Seribu were higher on the reef slope than on the reef edge. Pomacentridae and

Labridae were the dominant fish families at the reef of Kepulauan Seribu (Hutomo

1987, Suharsono et al. 1998).

According to Moll & Suharsono (1986), Kepulauan Seribu has 193 coral species belonging to 56 genera. The genera Acropora and Montipora dominate most of the coral communities in the reef flat and the upper reef crest (Hutomo 1987). Moll &

Suharsono (1986) found a high coral diversity in many reefs in Kepulauan Seribu.

The coral cover, average colony size and diversity indicated a gradual increase with distance from the mainland of Java. 88 species of scleractinian corals were described in the southern reefs and 190 species in the north of Kepulauan Seribu (Spalding et al.

6 2001). However, the species composition of the upper reef slope is dependent on environmental factors (Tomascik 1997).

FIGURE 1.1. Kepulauan Seribu Marine National Park (bordered by dash line) – the study area.

Since the 1920s the coral reefs in Jakarta Bay and some of the Seribu Islands have been studied. In the past they were generally in good condition, though human disturbance was already present (Moll & Suharsono 1986). Between 1985–1995,

7 most of these reefs were rapidly degrading (Moll & Suharsono 1986, UNESCO

2000). Reefs within Jakarta Bay were in dramatic decline, although they had already been in poor condition in 1985. Most of these reefs can be considered functionally dead (Ongkosongo & Sukarno 1986, Stoddart 1986). Three islands in this region disappeared below sea level during this time and several others were eroding, probably caused by a combination of dredging for landfill and natural loss of sediments (UNESCO 2000). A decline in coral reef cover was also observed 15 km to 50 km offshore from Java Island in 1995. However, several reefs had increased in coral cover. In this region, the major problems were natural and human disturbances.

The natural disturbances became apparent when outbreaks of the crown-of-thorns starfish occurred and water temperature increased due to the El Niño Southern

Oscillation Phenomenon (ENSO) (UNEP/IUCN 1988, Brown & Suharsono 1990,

Warwick et al. 1990). The human disturbances were identified as the poison fishing method, pollution from the Jakarta coastal area and the muro-ami coral breakage in the 1980s and 1990s (UNESCO 2000). Muro-ami is a fishing technique that uses a drive-in net and a line to scare the fish and drive them out of the reef toward a bag net

(often cause the breaking of live corals) (Erdmann 1998). Most reefs beyond 50 km off Java Island also indicated a decline in coral cover during 1985-1995. Destructive fishing practices like blast and cyanide fishing were the major problems in the outer- region (Brown 1986, UNEP/IUCN 1988; UNESCO 2000). However, the outer reefs of Kepulauan Seribu showed relatively high coral cover and diversity compared with reefs in Jakarta Bay.

According to Erdmann (1998) and UNESCO (2000), there was no evidence of blast fishing in Kepulauan Seribu from 1995 until the field research of this study started in 2000 (pers. com. with the Rangers of Kepulauan Seribu Marine National

8 Park). The disappearance of blast fishing may be related to the absence of target fishes and the establishment of a Marine National Park in this area (Ministry of

Forestry Decree No. 162/Kpts-II/1995, 21 March 1995) (UNEP/IUCN 1998).

However, Kepulauan Seribu was already declared as a reserve since 1982 (Ministry of

Agricultural Decree No. 257/Kpts/7/82, 21 July 1982) (BAPEDALDA 2000). But, unfortunately small-scale sodium cyanide fishing and illegal coral rock mining were still occurring in Kepulauan Seribu (Alder et al. 1994) until now. In contrast to blast fishing, the targets of cyanide fishing are ornamental fishes and invertebrates for the aquarium trade.

The area of Kepulauan Seribu Marine National Park is divided into four management-zones (Fig. 1.2) (KSMNP 2000). The first, Sanctuary (Core) Zone is a strict nature reserve, consisting of three areas: Sanctuary Zone I is set aside as a hawksbill turtle habitat, Sanctuary Zone II as a hawksbill nesting area, and Sanctuary

Zone III for the coral reef ecosystem. The second, Protection Zone, is purposed for protection of the Sanctuary Zone. The third, Intensive Utilization Zone is purposed for tourism activities, such as snorkeling, SCUBA diving, beach based activities and boating without conflict or environmental damage. The forth, Traditional Utilization

Zone is designated for traditional fishing methods using trap, net, and hand line fishing.

The anthropogenic impact on the coral reef ecosystem in the Sanctuary Zone and the Protection Zone was expected to be more obviously visible, when compared to the other zones, since this zone was designated for the protection and preservation of plants and animals. Entering this zone was strictly limited to research and educational activities. The anthropogenic impact in the Intensive Utilization Zone was expected to be moderate, due to its use for tourism activities. Considering all

9 zones in Kepulauan Seribu, the anthropogenic impact on the coral reef was predicted to be highest in the Traditional Utilization Zone.

FIGURE 1.2. The zones of Kepulauan Seribu Marine National Park.

10 The former blast fishing activities (in all zones) were indicated clearly by the large fields of coral rubble and subsequent new coral growth on rubble (although the author had not directly witnessed the former blast fishing activities). With this in mind, it seemed interesting to study how the reef fish-community has recovered from blast fishing practices in the past.

1.4. HYPOTHESES

It is hypothesized that coral reef fishes are more diverse and abundant in the

Sanctuary Zone. A second hypothesis postulates that reef fish communities have developed a clear pattern of relationship with the heterogeneity of benthic substrates.

This relationship corresponds to the degree of recovery of the coral reef habitat after five years of no blast fishing.

1.5. OBJECTIVES OF THE STUDY

The overall goal was to find information on reef fish assemblages associated with the recovery of coral reefs that had suffered from blast fishing activities several years ago.

The following specific questions were addressed in this study:

- Are impacts of blast fishing on a coral reef fish community still visible after five

years?

- What degree of relationship between varying heterogeneity of benthic substrates

can be found and is the reef fish community structure different in the sites/areas

now?

- Which environmental factors determine the structure of reef fish communities?

- Are reef fishes more diverse in the Sanctuary Zone than outside?

11 The study results are expected (1) to allow for the prediction of the succession of a reef fish community after blast fishing, (2) to contribute to the solution of maintaining the biodiversity, and (3) to provide information for evaluating the zoning management of the national park.

1.6. METHODOLOGICAL APPROACH

Several approaches were used for this study. The study was based on the following facts and assumptions: since 1995 until 2000 no blast fishing had occurred in all islands within the park (UNESCO 2000), so the coral reefs had already recovered at least partly. According to personal communication with the marine park rangers, there was no fishing in the Sanctuary Zone, and five years were enough time for fish communities to recover from blast fishing impact.

The coral reef coverage was assessed by taking underwater sequential photographs. This technique has the advantage, that it takes relatively little time in the field and provides a permanent record (Done 1981). However, it has also some disadvantages, like ineffectiveness in sampling small and hidden colonies, a very limited perception of depth (Done 1981), and it is very time-consuming to evaluate the pictures on the computer.

Underwater visual census (UVC) was used in this study to assess the reef fish community. UVC by SCUBA divers has been an important tool for fish ecologists in enumerating the abundance and composition of reef fish assemblages on coral reefs

(Sale & Sharp 1983, Bell et al. 1985, Harvey et al. 2002). The underestimation of reef fish densities is already known from this method (Sale & Sharp 1983, Bell et al.

1985, Harvey et al. 2001). However, trained observers showed consistent results in estimating the same population (Bell et al. 1985, Polunin & Roberts 1993).

12 Univariate and multivariate methods were applied to analyse the benthic substrate composition and the fish community pattern (Clarke & Green 1988). The fish communities were also assessed using species richness indices, Shannon diversity index and Pielou’s evenness index, and several species-abundance distribution models.

2. MATERIAL AND METHODS

2.1. THE STUDY AREA

Kepulauan Seribu is an island chain that consists of patch reef complexes and fringing reefs (Hutomo 1987, Tomascik 1997). The geographical position is between

5o24’ - 5o47’ south latitude and 106o23’ – 106o37’ east longitude. Around 25 km north from Java Island a deep channel (-88 m depth) separates the southernmost reefs from Java Island. Pari Island is the southernmost and the only platform of the

Kepulauan Seribu patch reef complex located on the southern side of the channel

(Ongkosongo & Sukarno 1986, Tomascik et al. 1997).

In Kepulauan Seribu, the extension of many islands and channels show a strong east-west orientation. In addition, the lateral reef growth is characteristically along an east-west axis (Tomascik et al. 1997). This phenomenon reflects the dominant east- west direction of winds and currents in the Java Sea (Ongkosongo & Sukarno 1986).

During the west monsoon (in general from December through March, dominant wind direction from the northwest; sometimes September-November is a transition to the west monsoon), however, currents in the southwest Java Sea are mostly in a southeast direction, sweeping across the Kepulauan Seribu at velocities generally not exceeding

40 cm.s-1 (Soegiarto 1981, Tomascik et al. 1997). During the east monsoon (in general from April through November) currents in the southwest Java Sea run in a southwest direction, with velocities exceeding sometimes 50 cm.s-1, generating a net flow into the Indian Ocean through the Sunda Strait (Tomascik et al. 1997). The east monsoon has a much larger impact on the islands geomorphology than the west monsoon (Ongkosongo & Sukarno 1986). During the west monsoon, the wind blows eastward and carries heavy rainfall throughout the region (Sukarno 1987). Then, the

14 city of Jakarta is becoming an increasingly important source for siltation and pollution in Jakarta Bay and Kepulauan Seribu, since many small rivers drain from this city

(Ongkosongo & Sukarno 1986, Willoughby 1986, Uneputty & Evans 1997,

Willoughby et al. 1997, Rees et al. 1999, Williams et al. 2000).

The reversing monsoon system is also the primary environmental factor structuring the coral-reef communities in the region (Hutomo 1987, Tomascik 1997).

The seaward reef slopes of Kepulauan Seribu have a relatively moderate angle, usually between 30o – 60o, with corals growing down to 20 m depth (Hutomo 1987,

Tomascik et al. 1997). Most of the islands have a narrow sandy shore and a wide reef flat (Hutomo 1987). However, the islands are considered to be located in a relatively sheltered environment, protected from severe storms and ocean swell (Tomascik et al.

1997). The low-amplitude (microtidal) diurnal-tide (i.e. one high, one low per day) in the Java Sea has a subordinate role in shaping current velocities that are predominant of monsoonal character (Tomascik et al. 1997).

2.2. SAMPLING SITES

Before the permanent sampling sites were chosen, a pre-survey was done in 30 islands. Based on the results of this survey, six islands with three sampling sites each

(on the northeast parts) were chosen in three management zones (for detailed position see Table 2.1). For the Sanctuary Zone two islands (Indonesian: Pulau) were selected:

Pulau (P.) Kayu Angin Bira and P. Putri Timur (for convenience they will be called as

Bira and Putri, respectively). In the Intensive Utilization Zone, P. Kayu Angin

Genteng and P. Melinjo were taken. P. Pandan and P. Opak Besar (Opak) were chosen as the Traditional Utilization Zone (Fig. 2.1).

FIGURE 2.1. The study sites were located in Kepulauan Seribu Marine National Park. Insets are the six selected islands with three sampling sites at each island.

16 TABLE 2.1. The geographical-position of sampling sites in each island.

Island (Code) Sites A-1: 05° 42.388' S A-2: 05° 42.403' S A-3: 05° 42.590' S P. Pandan (A) 106° 34.164' E 106° 34.114' E 106° 33.869' E B-1: 05° 40.008' S B-2: 05° 40.016' S B-3: 05° 40.024' S P. Opak Besar (B) 106° 35.188' E 106° 35.148' E 106° 35.137' E C-1: 05° 36.329' S C-2: 05° 36.327' S C-3: 05° 36.337' S P. Kayu Angin Bira (C) 106° 34.117' E 106° 34.076' E 106° 34.053' E D-1: 05° 35.326' S D-2: 05° 35.455' S D-3: 05° 35.531' S P. Putri Timur (D) 106° 34.074' E 106° 34.411' E 106° 4.417' E E-1: 05° 34.198' S E-2: 05° 34.196' S E-3: 05° 34.191' S P. Melinjo (E) 106° 32.552' E 106° 32.597' E 106° 32.645' E F-1: 05° 37.281' S F-2: 05° 37.147' S F-3: 05° 37.149' E P. Kayu Angin Genteng (F) 106° 33.764' E 106° 33.779' E 106° 33.796' S Abbreviation: S = Latitude South; E = Longitude East.

2.3. TIME FRAME OF STUDY

The pre-survey and preparation of this study was done between August and

September 2000. The main study was carried out from October 2000 until August

2001, with 45 day intervals between the sampling times. Unfortunately, the data from

December 2000 and January 2001 were lost (due to robbery). Thus only data of

October 2000, March, April, June, and August 2001 were available for the analysis.

Depending on the weather condition, between 9 to 12 days were needed each time to survey all the sampling sites. Each island was observed at least during one day. Underwater visual census along transects (see section 2.4.) was done first, followed by coral photography. It was always tried to minimize frightening the reef fish community.

2.4. PERMANENT TRANSECTS

Permanent transects (of 50 m length) for fish and corals were installed at fixed locations (using the same line transects) at 4 – 5 m depth, depending on the occurrence of new coral growth on fields of coral rubble. The transect lines were straight, following the depth contour and were laid down parallel to the reef front.

17 Both edges of the transect were demarcated by a cemented sinker into the reef pavement. Tape measures were laid out again between both marks at each survey, and then removed after each census. A Global Positioning System (GPS)-receiver was used to relocate the permanent transects.

2.5. CORAL SAMPLING

For fish and coral assessment belt transects were used. For coral assessment, it was a combination of line intercept transect (LIT) (English et al. 1994) and photogrammetry (Done 1981). Whereas the fish transect was 50 m x 5 m and the coral transect was one meter wide and 50 m long (English et al. 1994).

During the time of the survey period the percent cover of corals was assessed twice: at the beginning and at the end of the study. Therefore photographic methods were combined with the line intercept transect. The entire length of each 50 m transect was photographed using a Nikonos V camera with a 35-mm lens and a tetra- pod frame (Fig. 2.2) whereby the base of the rectangular frame served as reference bar. Continuous sequential photographs with 200-ASA negative films were taken along 50-m transect (the coverage of the camera lens was 1 m x 1.4 m when using the tetra-pod). A total of 1,292 photographs were scanned and the areas of the reef life- form categories measured using ImageJ V 1.14c (NIH) software (McCook (2001) used the same software) and converted to percent cover of benthic groups and life form categories.

The life-form categories used in this study were based on English et al. (1994):

Acropora Branching (ACB), Acropora Digitate (ACD), Acropora Tabulate (ACT),

Coral Branching (Non- Acropora) (CB), Coral Encrusting (CE), Coral Foliose (CF),

Coral Massive (CM), Coral Sub-massive (CS), Mushroom Coral (CMR), Millepora

(CME), Heliopora (CHL), Other Fauna (OT) (including: Soft Corals, Sponges,

18 Zoanthids, others benthic organisms), Algae (AL) (consisting of: Macro Algae,

Halimeda), Dead Coral (DC) (consisting of: dead coral with Algae, rubble and massive dead coral).

0.2 m

1.685 m

1 m

1 m FIGURE 2.2. The tetra-pod frame for photography coral coverage (modification from English et al. 1994).

The classification of coral colony size (related to the age) was based on several assumptions: the average coral growth in a linear direction was 24 mm per month (as the radius, r) (van Moorsel 1998). Another assumption was that the starting time of coral growth was 1995 to 2000, when there were no more blast fishing activities until the study was conducted. The third assumption was, that coral growth was in circular direction (van Moorsel 1988). The following equation was used to calculate the colony size:

Size area = π × r 2 where r = radius of coral colony (time-dependent, growth rate 24 mm/month), π = a constant, 3.14

19 2.6. REEF FISH SAMPLING

Though obtaining accurate assessment of reef fish abundance with underwater visual census (UVC) was not perfect and not a simple matter, UVC was the most practical non-destructive way and still permitted to estimate the abundance of reef fish species, with relatively quick time in the field, repeatable and inexpensive (Sale &

Sharp 1983, Bell et al. 1985, English et al. 1994, Samoilys & Carlos 2000).

The reef fish community was studied with the daytime underwater visual census method, recording the fish species and their abundance. The fish census was carried out between 10.00 a.m. and 3.00 p.m. to avoid possible diurnal-nocturnal behavioral changes (Carpenter et al. 1981, Helfman 1993). A census took about two hours, including the waiting time after laying out the measuring tape. Census was done only once per site.

Fish were generally identified to species level, but due to difficulties of getting fish samples for closer taxonomic inspection of specimen some taxa were identified only to genus level. Within genera every unidentified species was tentatively given a number to name as ‘species’. Identification of fish species was based on Burgess &

Axelrod (1972), Masuda et al. (1984), Allen & Steene (1987), Kuiter (1992), Lieske

& Myers (1997) and Allen (1999).

The following procedure was used (modified from Russ 1985; Greene &

Shenker 1993; English et al. 1994):

1. A species list of reef fishes was developed for the studied area (pre-survey result).

2. A 50-m measure tape was laid out followed by a waiting period of 45-60 minutes.

3. Two SCUBA divers swam very slowly (35-50 minutes) at 0.5 m above the

substratum along the 50-m transect. A single observer recorded the fish species

20 and its abundance on an underwater slate (Fig. 2.3), while the other served as a

dive buddy swimming behind the observer.

FIGURE 2.3. Observer swims along the 50-m permanent transect at 0.5 m above the substratum to visually census the reef fish (English et al. 1994).

2.7. DATA ANALYSES

Univariate methods were used to measure the percentage of coral cover and various diversity and evenness indices for both, coral and fishes. According to

Warwick et al. (1990), with adequate sample replication, the statistical significance of changes in the univariate indices can be assessed using a standard test. Multivariate analyses were used to visualize the species abundance matrix and the composition of benthic groups and life form categories (Clarke & Green 1988). Warwick et al.

(1990) found that low level perturbation in a community might be detected with greater sensitivity using multivariate rather than univariate analysis. Two multivariate methods used in the study were the ordination and clustering technique. The ordination technique was used to visualize the relationship between the samples

(Clarke & Green 1988). The cluster technique was used to form discrete groupings of

21 samples (Clarke & Green 1988). Clarke & Green (1988) suggested that combining both techniques is a good strategy, although descriptive multivariate analyses make no parametric assumption at all.

The data used for the analysis were pooled from three replicate sites in each island. The pooled fish abundance data for each island were analyzed using diversity indices. Both fish and benthic groups of fish were also analyzed by multivariate statistical methods.

Taylor (1978) stated that ‘diversity’ was seen as a property of the multi-species population that is equivalent to ‘density’ in a single-species population. According to

Magurran (1988) species diversity measurement can be divided into three categories:

The first are the species richness indices, which are essentially a measure of the number of species in a defined sampling unit. They instantly provide a comprehensive expression of diversity. In this category, number of species and

Margalef’s diversity index were used for this study. The second are the diversity indices based on the proportional abundance of species that seek to take richness and evenness into a single figure. This category includes the Shannon diversity index and

Pielou’s evenness index that were used in this study. The third are the species abundance models that describe the distribution of species abundances, whereby the relative abundance is considered to represent the basic pattern of niche utilization in the community or area (Southwood 1978). Four species abundance distribution models were examined in this study for the fish data: the log series (logarithmic series distribution), the log normal distribution (truncated log normal), the geometric series and MacArthur’s broken stick distribution model.

22 2.7.1. SPECIES RICHNESS

A simple measure of species diversity is the species number recorded (S) (Poole

1974). Margalef’s index (d) is an alternative measure of diversity to incorporate both the total number of individuals (N) and the species numbers. However, both S and d indices ignore the distribution of individuals among the species. Margalef’s index (d)

(Clarke & Warwick 1994) is calculated as:

()S −1 d = log N

2.7.2. DIVERSITY INDICES BASED ON THE PROPORTIONAL ABUNDANCE OF SPECIES

The Shannon diversity index (H’) is based on the proportional abundance of species assuming that individuals are randomly sampled from an ‘indefinitely-large’ community (Magurran 1988). The Shannon diversity index was used to measure the diversity:

s ′ H = −∑()piln pi i=1 n p = i ; i =1,2,3,...,S i N

where S = the number of species,

ni = the number of individuals of the ith species, N = the total number of individuals for all S species, and

pi = the proportional abundance of the ith species.

The variance of Shannon diversity index (Var H’) was calculated using the formula (Poole 1974, Magurran 1988):

2 s  s  p ()ln p 2 −  p ln p ) ∑∑i i i i S −1 Var H ′ = i==1  i 1  − N ()2N 2

23 To compare two Shannon diversity indices, a t-test was applied (Magurran

1988):

H1′ − H 2′ t = 1/ 2 (Var H1′ + Var H 2′ ) where H´1 is the Shannon diversity index in the first community and H´2 in the second community.

The degree of freedom was calculated according to (Magurran 1988):

()Var H ′ + Var H ′ 2 df = 1 2 2 2 ′(Var H1 )  ′(Var H 2 )    −    N1   N 2  where N1 and N2 were the number of individuals in the first and second sample, respectively. A t-table was used to look up the results.

The homogeneity of the reef fish community was measured by Pielou’s evenness index:

H ′ J ′ = H max where Hmax is the maximum possible diversity, which would be achieved if all species were equally abundant (= ln S) (Clarke & Warwick 1994).

2.7.3. FISH SPECIES-ABUNDANCE DISTRIBUTION MODELS

The equitability of the species-abundance relationship will reflect the underlying distribution (Southwood 1978). The rank of relative species abundance can be used to construct community models that are a characteristic pattern of the community (Fisher et al. 1943, May 1975, Pielou 1975, Southwood 1978, Magurran

1988). The log series distribution predicts that species arrive at an unsaturated habitat at random intervals of time and then occupy the remaining niche (with one or few dominant environment factors) (Magurran 1988). Theoretically, the community

24 consists of a small number of abundant species and many species with low abundance

(Magurran 1988). The log normal distribution of relative abundance indicates a large, mature and natural community with a large number of species fulfilling diverse ecological roles (niche) (May 1975, Magurran 1988). By contrast the geometric series distribution or the ‘nice-preemption’ hypothesis predicts that species arrive at an unsaturated habitat at regular intervals of time and occupy the remaining niche fraction (May 1975, Magurran 1988). The broken stick model describes a more equitable state of affairs than the three previous models, because it discusses more in rank-abundance form than in species abundance (May 1975, Magurran 1988).

2.7.3.1. THE LOG SERIES DISTRIBUTION

The general formula for log series distribution is calculated according to (Fisher et al. 1943):

 N  S =α ln 1+   α  and the distribution follows (Fisher et al. 1943, Poole 1974, Magurran 1988):

αx 2 αx3 αx n αx, , , ... , 2 3 n where α is a constant known as Fisher’s diversity index, x is a sampling parameter or a constant related to the average number of individuals per species and n is the abundance class. The total number of species (S) is obtained by:

S =α[]− ln()1− x

To calculate the expected frequencies in each abundance class, x is estimated by iterative solution:

S ()1− x  = []− ln()1− x N  x  where N is the total number of individuals in the community.

25 The α was calculated as: N()1− x α = x

The octaves or doublings of species abundance class was chosen for calculation.

To compare the observed species and abundance data with the expected value, a Chi squared (χ2)-test was done with (number of classes – 1) degrees of freedom (Sokal &

Rohlf 1995). Each class was calculated by:

()Observed - Expected 2 χ 2 = Expected

2.7.3.2. THE LOG NORMAL DISTRIBUTION

The log normal distribution can be written as (May 1975, Magurran 1988):

2 2 S(R) = S0exp (-a R ) where S(R) = the number of species in the R-th octave,

S0 = the number of species in the modal octave,

1/ 2 a = ()2σ 2 = the inverse width of the distribution

However, a truncated of log normal was used since most of log normal species abundance data are the truncated variety (May 1975, Pielou 1975, Magurran 1988).

The procedure is:

1. Each species abundance was converted into log10 ()x = log10 ni and then the

 x   ()x − x 2  mean  x = ∑  and the variance σ 2 = ∑  were calculated.      S   S 

2. x0 = log10 0.5 and xr = log10 r ; where r is the observed variate.

σ 2 3. γ was calculated using: γ = 2 ; where γ is a measure of the relationship ()x − x0 between the mode of the individuals curve and the upper limit of the species curve.

26 4. The auxiliary estimation function ()θˆ , which corresponds to the γ value, was found in Cohen’s table (Magurran 1988). ˆ 5. The estimation of mean ()µˆ x and variance (Vx ) of x were calculated using:

ˆ ˆ 2 ˆ 2 µˆ x = x −θ ()x − x0 and Vx = σ +θ ()x − x0

6. The standardized normal variate ()z0 , which corresponds to the truncation ()x − µˆ point of x , was calculated by z = 0 x 0 0 ˆ Vx

7. The area under the tail of a standard normal curve to the left of z0 or

p0 = Pr()Z ≤ z0 was found from tables of normal distribution. 8. The total number of species in the community (Sˆ *) was determined as s Sˆ* = 1− p0 9. The octaves or doublings of species abundance class was chosen for calculation. And Chi squared (χ2)-test was used with (number of classes – 3) degrees of freedom.

2.7.3.3. THE GEOMETRIC SERIES DISTRIBUTION

The species abundance rank in geometric series was sequenced from most to least abundant (May 1975, Magurran 1988):

i−1 ni = NCk k()1− k

where ni = the number of individuals in the ith species, N = the total number of individuals,

s −1 Ck = []1− ()1− k and is a constant which ensures that ∑ni = N

The constant (k) was calculated by iterating the following formula:

s N min  k  ()1− k  =   s  N ()1− k 1− ()1− k  where N min is the number of individuals in the least abundant species.

27 s −1 The value of the constant Ck was calculated as Ck = []1− ()1− k

A Chi squared (χ2)-test was used to find the goodness of fit with (number of species –

1) degrees of freedom.

2.7.3.4. THE BROKEN STICK DISTRIBUTION

In the broken stick distribution, the octaves or doublings of species abundance class was also used (Magurran 1988). The expected number of species was calculated by (May 1975):

S−2 S()S −1 1− n  S(n) =    N  N  where S(n) = the number of species in the abundance class with n individuals N = total number of individuals, S = total number of species

The observed and the expected number of species were used to calculate Chi squared (χ2)-test with degrees of freedom (number of classes – 1).

2.7.4. MULTIVARIATE ANALYSIS

Cluster analysis (CA) was used to group entities of the benthic groups and also the fish abundance into a dendrogram according to their similarities (Ludwig &

Reynolds 1988, Clarke & Warwick 1994, Legendre & Legendre 1998). For fish, the cluster analysis was based on the Bray-Curtis Similarity index with the group average linkage method. Data was transformed with square root without standardizing. For the benthic data the same method was used but data was not transformed.

Non-metric multidimensional scaling (NMDS) was used to construct an ordination of the benthic groups and the fish abundances in a 2D-map that plots dissimilar objects far apart and similar objects close to each other in the ordination space (Clarke & Warwick 1994, Legendre & Legendre 1998). The NMDS ordination

28 technique was based on Bray-Curtis similarity. The stress value that indicates how well that configuration represents the multidimensional similarity between the samples based on the classification from Kruskal (1964):

Stress Goodness of fit 20 % Poor 10 % Fair 5 % Good 2.5 % Excellent 0 % Perfect

Principal component analysis (PCA) was used to place the samples into a map that reflects their similarity like in NMDS (Clarke & Warwick 1994, Legendre &

Legendre 1998). PCA appeal was based on its apparent mathematical elegance

Ludwig & Reynolds 1988). In this study, PCA-ordination of two-way interaction

(with rows and columns centered) was used (Lipkovich & Smith 2002).

Canonical correspondence analysis (CCA) was employed to relate fish community compositions to variations of the benthic groups in the environment in a simultaneous two-dimensional plot (ter Braak 1986, Legendre & Legendre 1998,

Lipkovich & Smith 2002). CCA was calculated using the singular value decomposition (SVD) method of two-way matrix data. The CCA-plot was displayed with rows and columns centered and symmetric biplot scaling (Lipkovich & Smith

2002). The process of the multivariate computation (CA, NMDS and PCA) is summarized in Fig. 2.4.

NMDS

PCA

FIGURE 2.4. The process of the multivariate analysis (modified from Field et al. 1982). (CA: cluster analysis, PCA: principle component analysis, NMDS: non-metric multidimensional scaling).

Multivariate computations were performed with PRIMER 5 (Plymouth Routines in Multivariate Ecological Research) software (Clarke & Warwick 1994) and Biplot display was performed by Biplot and Singular Value Decomposition Macro for

Excel© developed by Lipkovich & Smith (2002). The diversity indices were calculated by PRIMER and manually. The distribution models were manually calculated by using Excel software. The linear regression was calculated automatically by Excel software.

3. RESULTS

3.1. FEATURES OF THE BENTHIC HABITAT

The percent cover of the major benthic groups (sum of all animals, plants and dead corals) was highly variable among the surveyed islands (Fig. 3.1). Dead corals were the most dominant cover in all surveyed islands: it was lowest at Genteng (51.6

%) and highest at Putri (83.4 %) (Appendix 1).

By contrast percent cover of hard corals was highest at Genteng (42.7 %) and lowest at Putri (7.6 %). The group of hard corals was divided into the two life form categories Acropora and Non-Acropora (Fig. 3.2 and 3.3). The Acropora life forms were further subdivided into three categories and Non-Acropora life forms were subdivided into eight categories (see Appendix 1). The average percent cover of both

Acropora and Non-Acropora life form categories were highly variable among the islands (Fig. 3.2).

The “other-fauna” (OT) group was present in all surveyed islands, but the cover never exceeded 7 % at any island (Fig. 3.1). This group consisted of 12 sub- categories, including soft corals. The algae group that consisted of three components, covered between 1.2 % and 6.9 % (Fig. 3.1, Appendix 1).

The islands in the Sanctuary Zone (Bira) and in the border of the Sanctuary

Zone (Putri) were characterized by a high number of dead corals (Fig. 3.1). The coverage of dead corals in Bira was 3.6 times and in Putri 11 times higher than the cover of hard corals.

Melinjo and Genteng, which are located in the Intensive Utilization Zone, were in better condition compared with the two islands of the Sanctuary Zone. In Melinjo the cover of dead corals was 2.6 times higher than the live coral cover. Genteng had

31 the lowest value of dead coral cover divided by live coral (only 1.2). The hard coral cover in Melinjo and Genteng amounted to 25 % and 42.8 %, respectively.

Pandan and Opak (Traditional Utilization Zone) had 29.1 % and 18.2 % of hard coral cover, respectively. The comparison of dead corals to hard coral cover in

Pandan was 2.2 and in Opak 2.9.

Among the other dead coral components rubble had the highest cover in all islands (Fig. 3.4). The coverage of rubble was between 30.6 % and 58.6 %, being highest in Putri, followed by Bira.

Small coral colonies were dominant in all areas surveyed (Fig. 3.5, Appendix 2).

Their cover was lowest in Genteng (79.4 %) and the highest in Bira (90.4 %).

Cover (%)

P. KA Bira P. Putri Timur P. Melinjo P. KA Genteng P. Opak Besar P. Pandan

Dead Coral Hard Coral Other Fauna Algae

32 10

4 Cover (%)

P. KA Bira P. Putri Timur P. Melinjo P. KA Genteng P. Opak Besar P. Pandan

ACB ACT ACD

FIGURE 3.2. Percent cover of Acropora life form categories: Acropora Branching (ACB), Acropora Digitate (ACD) and Acropora Tabulate (ACT).

Cover (%)

P. KA Bira P. Putri Timur P. Melinjo P. KA Genteng P. Opak Besar P. Pandan

CS CF CB CM CE

FIGURE 3.3. Percent cover of Non-Acropora life form categories, consisting of: Coral Sub- massive (CS), Coral Foliose (CF), Coral Branching (CB), and Coral Encrusting (CE).

33 70

Cover (%)

P. KA Bira P. Putri Timur P. Melinjo P. KA Genteng P. Opak Besar P. Pandan

DCR DCM DCA

FIGURE 3.4. Percent cover of dead coral in each island, consisting of: rubble dead corals (DCR), massive dead corals (DCM), and dead corals with algae (DCA).

100

30 Number of colony (%)

0 P. KA Bira P. Putri Timur P. Melinjo P. KA Genteng P. Opak Besar P. Pandan

< 651 cm2 651 - 940 cm2 > 940 cm2

FIGURE 3.5. Average percentage of the number of colonies for all hard coral categories.

34 3.2. PATTERN OF MAJOR BENTHIC GROUPS AND LIFE FORM CATEGORIES

Between the surveyed islands the composition of the benthic habitat was highly variable. Multivariate analyses were used to find linkages among them. Figure 3.6 shows a hierarchical dendrogram. At a similarity level of 77 % three different benthic and life form groups were distinguished. The first group consisted of the islands Bira and Putri (at 83.7 % similarity level) that are both located in the Sanctuary Zone of the national park. The second group was Pandan, Melinjo and Genteng (at 77.6 % similarity level). The third group consisted of Opak only.

80 (II) (I) (III) Similarity 90

100 P. Melinjo (E) P. KA Bira (C) P. Pandan (A) P. Putri Timur (D) P. Opak Besar (B) P. KA Genteng (F)

West side East side

35 The NMDS-plot of all components of benthic groups and life form categories showed a slightly different trend in the separation of the islands than the dendrogram

(Fig. 3.7). In the NMDS-plot Bira and Putri, both are located in the Sanctuary Zone, were grouped together. Genteng, Melinjo and Pandan built another group. Opak was markedly separated from these two groups.

P. KA Bira (C) Sanctuary Zone West side (I) P. Putri Timur (D) (II)

Intensive Utilization Zone

P. KA Genteng (F) East side P. Melinjo (E)

P. Pandan (A) (III) P. Opak Besar (B) Stress: 0.0 Traditional Utilization Zone

FIGURE 3.7. NMDS plot of all components of benthic groups and life form categories.

PCA-ordination showed a different trend in the grouping of the islands, when compared to the two previous methods (Fig. 3.8). The islands of the Sanctuary Zone,

Bira and Putri, were grouped together. Genteng and Pandan built another group.

Melinjo and Opak were clearly separated from the two former groups.

36 4

3 P. Opak Besar (B) DCA

2 P. Putri Timur (D) DCM P. KA Bira ( C) 1 AL-C DCR CS ACT AL-H OT-all categories CM CMR 0 CME CHL AL-M -6 -4 -2 0ACD 2 4PC-1: 51.2 % 6 CE DCT DCB CB ACB -1 P. Melinjo (E)

P. Pandan (A) -2

P. KA Genteng (F)

-3

-4 CF PC-2: 35.7 %

-5

FIGURE 3.8. The PCA-biplot of benthic groups and life form categories.

3.3. REEF FISH COMMUNITY

A total of 32,863 fishes were censused from 18 permanent sites during the study period, but the data does not include small pelagic fishes (Appendix 3). Altogether

119 fish species belonging to 25 families were observed (Table 3.1.). The minimum and maximum abundances per island and per observation ranged between 651 and

1,006 individuals (Table 3.2.). In general Pomacentridae was the most abundant family at all times in all islands. Two families (Pomacentridae and Labridae) tended to be the most abundant in each island, followed by Scaridae, Chaetodontidae,

Nemipteridae and Apogonidae (Fig. 3.9 & 3.10). Further families were of low abundance.

Planktivore and omnivore fish were the two most abundant trophic groups in each island and the whole surveyed area (Fig. 3.11 & 3.12; Appendix 4) followed by benthic feeders, herbivores, coralivores, piscivores and detritivores. In the

Traditional Utilization Zone planktivores were obviously the most abundant trophic group during the study, except in Opak where the omnivores were most abundant in

37 March and April 2001. In the Intensive Utilization Zone omnivores were generally the most abundant trophic group (Fig. 3.11 & 3.12). However with exception, in

Melinjo benthic feeders were abundant in October 2000 and in Genteng planktivores were the most abundant in March 2001. In the Sanctuary Zone (Bira), omnivores were most abundant from April – August 2001 (during the east monsoon), whereas in

October 2000 during the west monsoon), benthic feeders were the most abundant group.

At the beginning of the study (October 2000), the number of fish species was generally lower compared to all other censuses in all observation sites (Fig. 3.13).

However, the fish abundance at the beginning of the study was not always lower when compared to the following observations (Table 3.2.). The fish diversity index (H’) also changed during the study (ranged 2.36 to 3.19) (Table 3.2.). Fish evenness is given in Table 3.2.

38 TABLE 3.1. Complete list of fish families and species according to the systematic order produced by the visual census method in all surveyed islands.

Muraenidae Pomacanthidae Labridae 1 Gymnothorax sp. 37 Centropyge bicolor 82 Anampses sp. Holocentridae 38 Chaetodontoplus mesoleucus 83 Cheilinus chlorourus 2 Myripristis adusta 39 Pomacanthus sp. 84 Cheilinus fasciatus 3 Myripristis violacea Pomacentridae 85 Cheilinus undulatus 4 Myripristis sp. 40 Abudefduf vaigiensis 86 Choerodon anchorago 5 Sargocentron praslin 41 Abudefduf bengalensis 87 Cirrhilabrus cyanopleura Synodontidae 42 Abudefduf sexfasciatus 88 Diproctacanthus xanthurus 6 Synodus sp. 43 Amblyglyphidodon curacao 89 Epibulus insidiator Aulostomidae 44 Amblyglyphidodon leucogaster 90 Gomphosus varius 7 Aulostomus chinensis 45 Amblyglyphidodon ternatensis 91 Halichoeres argus Fistulariidae 46 Amphiprion frenatus 92 Halichoeres chloropterus 8 Fistularia commersonii 47 Amphiprion ocellaris 93 Halichoeres hortulanus Tetrarogidae 48 Amphiprion percula 94 Halichoeres melanurus 9 Ablabys taenianotus 49 Amphiprion sandaracinos 95 Halichoeres purpurescens Scorpaenidae 50 Amphiprion sp. 96 Halichoeres vrolikii 10 Pterois volitans 51 Cheiloprion labiatus 97 Hemigymnus melapterus Serranidae 52 Chromis analis 98 Labroides dimidiatus 11 Cephalopholis argus 53 Chromis atripectoralis 99 Macropharyngodon ornatus 12 Cephalopholis boenak 54 Chromis flavipectoralis 100 Pteragogus sp. 13 Cephalopholis sp. 1 55 Chromis viridis 101 Stethojulis strigiventer 14 Cephalopholis sp. 2 56 Chromis weberi 102 Thalassoma hardwicke 15 Epinephelus sp. 1 57 Chromis xanthura 103 Thalassoma lunare 16 Epinephelus sp. 2 58 Chromis sp. 104 Thalassoma lutescens 17 Epinephelus sp. 3 59 Chrysiptera rollandi 105 Thalassoma purpureum Apogonidae 60 Chrysiptera sp. Scaridae 18 Apogon compressus 61 Dascyllus aruanus 106 Scarus ghobban 19 Cheilodipterus macrodon 62 Dascyllus trimaculatus 107 Scarus niger 20 Cheilodipterus quinquelineatus 63 Dischistodus melanotus 108 Chlorurus sordidus 21 Sphaeramia nematoptera 64 Dischistodus prosopotaenia 109 Scarus viridifucatus Lutjanidae 65 Neoglyphidodon bonang 110 Scarus sp. 1 22 Lutjanus biguttatus 66 Neoglyphidodon melas 111 Scarus sp. 2 23 Lutjanus decussatus 67 Neoglyphidodon nigroris Blenniidae 24 Lutjanus fulviflammus 68 Neopglyphidodon oxyodon 112 Meiacanthus smithi Haemulidae 69 Neopomacentrus anabatoides Microdesmidae 25 Plectorhinchus chaetodonoides 70 Neopomacentrus azysron 113 Ptereleotris evides Nemipteridae 71 Plectroglyphidodon lacrymatus Acanthuridae 26 Pentapodus trivittatus 72 Pomacentrus alexanderae 114 Acanthurus lineatus 27 Scolopsis bilineata 73 Pomacentrus amboinensis Siganidae 28 Scolopsis lineatus 74 Pomacentrus grammorhyncus 115 Siganus canaliculatus 29 Scolopsis margaritifer 75 Pomacentrus lepidogenys 116 Siganus corallinus Mullidae 76 Pomacentrus philippinus 117 Siganus vulpinus 30 Parupeneus barberinus 77 Pomacentrus sp. 1 Ostraciidae Ephippidae 78 Pomacentrus sp. 2 118 Ostracion cubicus 31 Platax sp. 79 Pomacentrus sp. 3 Tetraodontidae Chaetodontidae 80 Pomacentrus taeniometopon 119 Arothron sp. 32 Chaetodon auriga 81 Stegastes fasciolatus 33 Chaetodon octofasciatus 34 Chaetodon vagabundus 35 Chelmon rostratus 36 Heniochus sp.

39 (a) 90 October 2000 80

40 Abundance (%) 30

0 P. KA Bira P. Putri Timur P. Melinjo P. KA Genteng P. Opak Besar P. Pandan

(b) 90 March 2001 80

40 Abundance (%) 30

0 P. KA Bira P. Putri Timur P. Melinjo P. KA Genteng P. Opak Besar P. Pandan

40 Abundance (%) 30

P. KA Bira P. Putri Timur P. Melinjo P. KA Genteng P. Opak Besar P. Pandan

Pomacentridae Labridae Scaridae Chaetodontidae Nemipteridae Apogonidae

40 (d) 90 June 2001 80

40 Abundance (%) 30

0 P. KA Bira P. Putri Timur P. Melinjo P. KA Genteng P. Opak Besar P. Pandan

(e) 90 August 2001 80

40 Abundance (%) 30

P. KA Bira P. Putri Timur P. Melinjo P. KA Genteng P. Opak Besar P. Pandan

Pomacentridae Labridae Scaridae Chaetodontidae Nemipteridae Apogonidae

FIGURE 3.9. Continued.

40 Abundance (%) 30

Oct. 00 Mar. 01 Apr. 01 Jun. 01 Aug. 01

Pomacentridae Labridae Scaridae Chaetodontidae Nemipteridae Apogonidae

FIGURE 3.10. Abundance of the most abundant fish families during the time of the study. Data were pooled from all sites in each island.

41 (a) 900 October 2000 800

700

600 572 503

500 482

455

400 384

306

299

Individual number

300 278 278 272 262

241

209

200

161 160

116

100 81 69

46 44

40 15 15 13 7 4 4 4 2 2 2 2 1 1 0 0 0 0 0 0 0 0 P. KA Bira P. Putri Timur P. Melinjo P. KA Genteng P. Opak Besar P. Pandan

(b) 900 March 2001 800

700

600 532

488 500

453

401 388

400 383

368 368 365 363

329

291

Individual number 300

255 235

184

200 178

163

158

119

110

100 71

46 39 38

12 10 10 10 10 8 8 8 7 5 5 4 4 2 2 1 0 0 0 P. KA Bira P. Putri Timur P. Melinjo P. KA Genteng P. Opak Besar P. Pandan

April 2001

800 772

700

600 562 555

500

463 450

400 385

354 354

320

292 289 288 278

300 277

269 Individual number

243 234 229

211

200 183 164 154

100

68 63

20 17 16 16 15 14 10 10 7 7 5 3 2 2 1 0 0 0 0

P. KA Bira P. Putri Timur P. Melinjo P. KA Genteng P. Opak Besar P. Pandan

Planktivore Omnivore Benthic feeder Herbivore Detritivore Corallivore Piscivore

FIGURE 3.11. Abundance of the different trophic groups at each study site during the time of study: October 2000 (a), March 2001 (b), April 2001 (c), June 2001 (d), and August 2001 (e).

42 (d) 900 June 2001 800

700 680 609

600

533

511 504

500

410

399

400

337

310

302

Individual number

300 278 255

242 233

213 208 208

200 198

173

154 142

100 72

27 16 14 12 9 9 7 5 5 4 3 2 2 1 1 0 0 0 0 P. KA Bira P. Putri Timur P. Melinjo P. KA Genteng P. Opak Besar P. Pandan

(e) 900 August 2001 800 710 700

600 510 500

428

400 391

372

350

315

300 284 Individual number 263 263 254

245

220 206 204 198 184

200 175

152 140 137

100 86

32 30

23 15 12 11 11 10 8 7 5 5 3 1 1 0 0 0 0 0 0

P. KA Bira P. Putri Timur P. Melinjo P. KA Genteng P. Opak Besar P. Pandan

Planktivore Omnivore Benthic feeder Herbivore Detritivore Corallivore Piscivore

FIGURE 3.11. Continued.

3000 2748

2642

2500

2379 2362 2329

2159

2138

2015

2000

1836

1661

1536

1472

1500 1454

1384

1118

1000

889 Individual number 851

668

500 476

209

77 73 70 50 38 36 32 30 28 28 25 27 17 6 0 0

Oct. 00 Mar. 01 Apr. 01 Jun. 01 Aug. 01

Omnivore Planktivore Benthic feeder Herbivore Detritivore Corallivore Piscivore

FIGURE 3.12. Abundance of different trophic fish groups during the time of the study. Data were pooled from all islands.

43 (a) 60 P. Pandan

20 Number of species

0 Oct. '00 Dec. '00 Mar. '01 Apr. '01 Jun. '01 Aug. '01 Jan. '01

(b) 60 P. Opak Besar

20 Number of species

0 Oct. '00 Dec. '00 Mar. '01 Apr. '01 Jun. '01 Aug. '01 Jan. '01

20 Number of species

0 Oct. '00 Dec. '00 Mar. '01 Apr. '01 Jun. '01 Aug. '01 Jan. '01

44 (d) 60 P. Putri Timur

20 Number of species

0 Oct. '00 Dec. '00 Mar. '01 Apr. '01 Jun. '01 Aug. '01 Jan. '01

(e) 60 P. Melinjo

20 Number of species

0 Oct. '00 Dec. '00 Mar. '01 Apr. '01 Jun. '01 Aug. '01 Jan. '01

(f) 60 P. KA Genteng

20 Number of species

0 Oct. '00 Dec. '00 Mar. '01 Apr. '01 Jun. '01 Aug. '01 Jan. '01

FIGURE 3.13. Continued.

45 TABLE 3.2. The diversity of fishes calculated by using some diversity formulas (A), and the distribution model of fish species abundance in each island and for all islands together (B). The χ2 test is used to describe the goodness-of-fit of the distribution model with P<0.05. The percent value in brackets indicates the probability of the observed data to be the same as the expected distribution model.

October 2000 March 2001 April 2001

Pandan Opak Bira Putri Melinjo Genteng Pandan Opak Bira Putri Melinjo Genteng Pandan Opak Bira Putri Melinjo Genteng A. Diversity indices S (Total species) 37 33 33 33 44 40 49 50 55 45 49 44 54 49 55 48 56 50 d (Species 5.56 4.64 4.70 4.89 6.37 5.44 6.94 6.77 7.88 6.57 6.81 6.11 7.32 6.78 7.69 6.68 7.62 6.76 richness) N (Total 651 983 900 699 851 1295 1007 1384 947 811 1149 1133 1392 1193 1122 1133 1361 1401 individuals) J' (Evenness) 0.65 0.72 0.73 0.81 0.75 0.77 0.70 0.80 0.71 0.75 0.69 0.79 0.74 0.82 0.77 0.80 0.73 0.78

H' (loge) 2.36 2.52 2.56 2.84 2.84 2.84 2.74 3.15 2.85 2.85 2.68 3.01 2.94 3.19 3.10 3.11 2.93 3.05 α Diversity (Fisher) 8.50 6.58 6.73 7.20 9.84 7.82 10.77 10.16 12.72 10.27 10.39 9.11 11.17 10.29 12.12 10.16 11.77 10.13 B. Fit of Distribution Model Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Logarithmic series (24.9%) (99.4%) (68.5%) (29.3%) (76.6%) (14.2%) (79.7%) (79.1%) (38.4%) (96.8%) (72.3%) (31.6%) (22.1%) (35.5%) (43.7%) (29.2%) (95.9%) (92.4%) Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Log normal No (0%) (28.5%) (89.5%) (52.2%) (35.8%) (30.6%) (77.2%) (15.9%) (30.8%) (95.1%) (46.4%) (51.1%) (63.5%) (15.6%) (31.8%) (77.7%) (86.5%) (49.3%) No Yes Yes Geometric series No (0%) No (0%) No (0%) No (0%) No (0%) No (0%) No (0%) No (0%) No (0%) No (0%) No (0%) No (0%) No (0%) No (0%) No (0%) (0%) (28.8%) (99.8%) No Broken stick No (0%) No (0%) No (0%) No (0%) No (0%) No (0%) No (0%) No (0%) No (0%) No (0%) No (0%) No (0%) No (0%) No (0%) No (0%) No (0%) No (0%) (0%)

June 2001 August 2001 All islands

Pandan Opak Bira Putri Melinjo Genteng Pandan Opak Bira Putri Melinjo Genteng Oct. 00 Mar. 01 Apr. 01 Jun. 01 Aug. 01 A. Diversity indices S (Total species) 48 36 48 51 48 49 49 45 45 48 44 41 82 84 84 84 81 d (Species 6.42 5.05 6.47 7.32 6.82 6.68 6.55 6.30 6.52 7.00 6.24 5.78 9.44 9.47 9.29 9.35 9.15 richness) N (Total 1504 1024 1425 930 987 1320 1521 1077 851 822 979 1011 5310 6431 7602 7190 6261 individuals) J' (Evenness) 0.72 0.73 0.71 0.79 0.71 0.75 0.69 0.77 0.73 0.75 0.72 0.77 0.73 0.74 0.77 0.70 0.71

H' (loge) 2.80 2.60 2.74 3.10 2.73 2.94 2.67 2.94 2.77 2.90 2.72 2.85 3.23 3.27 3.40 3.09 3.11 α Diversity (Fisher) 9.46 7.26 9.58 11.60 10.55 10.02 9.68 9.49 10.13 11.12 9.47 8.58 13.76 13.64 13.21 13.35 13.13 B. Fit of Distribution Model Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Logarithmic series No (0%) (18.7%) (54.3%) (91.5%) (83.4%) (19.2%) (9.2%) (19.8%) (40.2%) (68.9%) (98.2%) (51.2%) (97.6%) (15.3%) (1.8%) (17.5%) (31.9%) Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Log normal No (0%) (18.8%) (45.3%) (94.0%) (59.9%) (12.0%) (21.0%) (54.4%) (45.4%) (78.0%) (28.8%) (84.1%) (35.4%) (34.9%) (18.2%) (73.2%) (93.2%) Geometric series No (0%) No (0%) No (0%) No (0%) No (0%) No (0%) No (0%) No (0%) No (0%) No (0%) No (0%) No (0%) No (0%) No (0%) No (0%) No (0%) No (0%) Broken stick No (0%) No (0%) No (0%) No (0%) No (0%) No (0%) No (0%) No (0%) No (0%) No (0%) No (0%) No (0%) No (0%) No (0%) No (0%) No (0%) No (0%)

46 3.4. FISH DIVERSITY

The Shannon diversity index (H’) (Table 3.2.) was used for the comparison of fish communities in the Sanctuary Zone (Bira and Putri), the Intensive Utilization

Zone (Melinjo and Genteng), and the Traditional Utilization Zone (Pandan and Opak)

(see Table 3.3 and Table 3.4). Most of the comparison carried out for Bira showed no significant differences to the other islands (only 8 of 25 comparisons showed significant differences) (Table 3.3). Though the results of the significance tests do not allow stating a clear difference between Bira and the other islands in terms of diversity (measured as H’). Bira seemed to be slightly lower in fish diversity than the other islands except in April 2001 if compared to Melinjo. Putri seemed to be the most diverse island in comparison to the others, which can be seen in a significantly higher value of H’ (Table 3.3). The Shannon diversity index in each island in October

2000 seemed to be lower compared to the following months (Table 3.4). The other diversity indices were also calculated for fish community (Table 3.2).

P. Putri P. Melinjo P. KA P. Pandan P. Opak

Timur (D) (E) Genteng (F) (A) Besar (B) October 2000 s. (CE) n.s. n.s. n.s. (C) June 2001 s. (C

P. Melinjo P. KA P. Pandan P. Opak (E) Genteng (F) (A) Besar (B) October 2000 n.s. n.s. s. (D>A) s. (D>B) March 2001 n.s. n.s. n.s. s. (DE) n.s. s. (D>A) n.s. (D) June 2001 s. ((D>E) s. (D>F) s. (D>A) s. (D>B) August 2001 n.s. n.s. s. (D>A) n.s.

47 TABLE 3.4. Comparison of Shannon diversity index (H') between the sampling times in all islands. The t-test was performed at a significance level of P<0.001 (n.s. = Not significantly different; s. = Significantly different).

P. Pandan (A) (2) March 2001 (3) April 2001 (4) June 2001 (5) August 2001 (1) October 2000 s. (1<2) s. (1<3) s. (1<4) s. (1<5) (2) March 2001 - s. (2<3) n.s. n.s. (3) April 2001 - - n.s. s. (3>5) (4) June 2001 - - - n.s.

P. Opak Besar (B) (2) March 2001 (3) April 2001 (4) June 2001 (5) August 2001 (1) October 2000 s. (1<2) s. (1<3) n.s. s. (1<5) (2) March 2001 - n.s. s. (2>4) s. (2>5) (3) April 2001 - - s. (3>4) s. (3>5) (4) June 2001 - - - s. (4<5)

P. KA Bira (C) (2) March 2001 (3) April 2001 (4) June 2001 (5) August 2001 (1) October 2000 s. (1<2) s. (1<3) s. (1<4) s. (1<5) (2) March 2001 - s. (2<3) n.s. n.s. (3) April 2001 - - s. (3>4) s. (3>5) (4) June 2001 - - - n.s.

P. Putri Timur (D) (2) March 2001 (3) April 2001 (4) June 2001 (5) August 2001 (1) October 2000 n.s. s. (1<3) s. (1<4) n.s. (2) March 2001 - s. (2<3) s. (2<4) n.s. (3) April 2001 - - n.s. s. (3>5) (4) June 2001 - - - s. (4>5)

P. Melinjo (E) (2) March 2001 (3) April 2001 (4) June 2001 (5) August 2001 (1) October 2000 n.s. n.s. n.s. n.s. (2) March 2001 - n.s. n.s. n.s. (3) April 2001 - - s. (3>4) s. (3>5) (4) June 2001 - - - n.s.

P. KA Genteng (F) (2) March 2001 (3) April 2001 (4) June 2001 (5) August 2001 (1) October 2000 s. (1<2) s. (1<3) n.s. n.s. (2) March 2001 - n.s. n.s. n.s. (3) April 2001 - - n.s. s. (3>5) (4) June 2001 - - - n.s.

All islands (2) March 2001 (3) April 2001 (4) June 2001 (5) August 2001 (1) October 2000 n.s. s. (1<3) s. (1>4) s. (1>5) (2) March 2001 - s. (2<3) s. (2>4) s. (2>5) (3) April 2001 - - s. (3>4) s. (3>5) (4) June 2001 - - - n.s.

48 3.5. FISH SPECIES-ABUNDANCE RELATIONSHIP MODEL

The species rank order (sequence) based on their abundances at each island and all islands combined can be seen in Fig. 3.14 – 3.20. The most abundant species belong to the families Pomacentridae and Labridae, and in some islands also to the families Scaridae and Chaetodontidae.

Four main models were examined for the fish species abundance data: the log series (logarithmic series distribution), the log normal distribution (truncated log normal), the geometric series and MacArthur’s broken stick distribution model (Table

3.2). All data on fish species abundance was fitted to the log series distribution.

However, all of the data also fitted the log normal distribution except two data sets

(Table 3.2) that only fitted to a geometric series distribution. There was no fish species data set that fitted to the broken stick distribution model (Table 3.2.).

Most of the data on species abundance fitted the log series and the log normal distribution. Only two data sets fitted to the log series, the log normal and the broken stick (with χ2 test, P>0.05). The χ2 value of each species abundance data set was used to find a higher probability being the same with the model, the higher percentage was more appropriate to the model (Table 3.2.).

49 (a) 6 Oct '00 Mar '01 5 Apr '01 Jun '01

4 Aug '01

3 Abundance (ln) 2