The impact of live rock harvesting on fish abundance, substrate composition and reef topography along the Coral Coast, Fiji Islands
By
Make Liku Movono
A thesis submitted in partial fulfilment of the requirements for the degree of Master of Science
School of Marine Studies Faculty of Island and Oceans The University of the South Pacific
December, 2007 Dedication
This is for my Normie and to God Almighty!
Declaration of Originality
I Make Liku Movono declare that this thesis is my own work and that, to the best of my knowledge, it contains no material previously published or substantially overlapping with material submitted for the award of any other degree at any institution, except where due acknowledgement is made in the text.
Make Liku Movono Date
The current research was conducted under mine and other co-supervisors and I am certain that this is the sole work of Ms Make Liku Movono.
i ACKNOWLEDGEMENTS
First and Foremost, I would like to thank my God Almighty for bringing me through these challenging times and has never failed me! In addition to this, acknowledging the financial assistance by the Institute of Applied Science at the
University of the South Pacific with which this project would not have been possible. A big “vinaka vakalevu” to Professor William Aalbersberg for giving me an opportunity to work on a challenging and vital issue. To the communities, whom without their concern, this study would not have been initiated. A very big
“vinaka vakalevu” to Dr James Reynolds, who was with me from “scratch” till the very end, justifying every detail of the work.
Heartfelt thanks goes to the communities of Namada, Namatakula, Vatukarasa,
Votua and Malevu for their hospitality in hosting me while I was doing my field work. To Alena, Bola, Kini, Jolame, the boys in Votua and Namatakula for assisting me in the field. Also the IAS boys- Ron V, Ron S and Rusi for assistance in field work. I know this would not have been possible if it weren’t for their tremendous help.
To James Comely for helping me with the editing and taking me through the stages. Also would like to thank Dr Clare Morrison for going through my work and great advice. Not forgetting Cherie of Marine Aquarium Council and Priti
Singh.
ii Lastly I would like to thank the Warbler House occupants, Hilda, Nuns and Clare for the great support. My wonderful friend Salote “Dudlz” Waqairatu for just being a great . This is goes the same for Lewa, for always being supportive in every way. My parents, bu and baby sitters for looking after Normie when I had to work late nights. Finally to my Normie for being just a source of joy! And to all those who I forgot to mention but have been there in one way or the other.
iii Abbreviations
CA Coralline Algae CAMP Council Collection Area Management Plan CCA Crustose Coralline Algae CCC Coral Cay Conservation CITES Convention on International Trade in Endangered Species CV Coefficient of variation DOM Dissolved Organic Matter EAM Epithilic Algal Matrix EPS Endangered Protected Species FLMMA Fiji Locally Managed Marine Areas FMAC Fiji Marine Aquarium Council FSPI Foundation for the Peoples the South Pacific International H Harvested Reefs IAS Institute of Applied Science ICM Integrated Coastal Management IMA International Marine Life Alliance MA Management Authority MAC Marine Aquarium Council NBSAP National Biodiversity Strategic Action Plan NDF Non Detriment Finding NH Non Harvested Reefs MOTA Marine Ornamental Traders Association MPA Marine Protected Areas SC Scientific Council WSI Walt Smith International WWF World Wildlife Fund
iv ABSTRACT
The lucrative live rock trade, of which Fiji is the major exporter, has raised concerns on sustainability and ecological impacts. This study is the first to quantify the ecological impacts of live rock removal. The abundance of seven fish families (Chaetodontidae, Blennidae, Gobidae, Pomacanthidae, Pinuipedidae,
Pomacentridae and Synodontidae), reef substrate composition and topography were compared between four harvested and four non-harvested reefs along the
Coral Coast, Fiji. Belt transect method was used for fish counts, point intercept method for substrate composition and a graduated rod was used to take depths for profiling. The abundance of Chaetodontidae, Blennidae, Pomacanthidae and
Synodontidae was significantly higher in the non harvested reefs while
Pinuipedidae were significantly more abundant in the harvested reefs. There were significantly more coralline algae and live coral in the non-harvested reefs and higher algae in the harvested reefs. The harvested reefs were on average significantly deeper compared to the non-harvested reefs. There was a significant variation in Coefficient of Variation (CV) between the four harvested reefs and non-harvested reefs. The observed differences in fish abundance, substrate composition and depth between harvested and non harvested reefs are indications of the adverse impact of live rock removal on reef flats. This study provides scientific evidence of the impact of live rock trade on reef ecology which will help government with decisions on the future of the trade in Fiji. We recommend short term measures including sustainable collection method
v guidelines along with long term goals to gradually phase out harvesting within five years by introducing cultured rocks as an alternative source of income.
vi INTRODUCTION ...... 1 CHAPTER 1: LITERATURE REVIEW...... 4 1.1 History of the trade ...... 4 1.1.1 Marine Aquarium Trade World-Wide...... 4 1.1.2 Marine Aquarium Trade in the Pacific Region...... 6 1.1.3 Aquarium trade in Fiji...... 7 1.2 Convention on International Trade in Endangered Species (CITES) ...... 9 1.2.1 Non Detriment Findings (NDF) ...... 11 1.2.2 Management...... 12 1.4 Previous Studies on Live Rock ...... 16 1.4.1 International ...... 17 1.4.2 National ...... 18 1.5 Coral Reef Communities...... 22 1.5.1 Benthic microflora, periphyton and plant associations...... 23 1.5.2 The periphiton communitiy/ live rock communitiy...... 24 1.6 Importance of live rock ...... 25 1.6.1 Calcification...... 25 1.6.2 Biogeochemical cycle ...... 26 1.6.3 Photosynthesis ...... 26 1.6.4 Habitat and food source...... 27 1.7 Disturbance on coral reef communities ...... 28 1.7.1 Reef Fishes in coral reef communities...... 30 1.8 Indicator Fish species...... 31 1.8.1 Chaetodonids (Butterflyfish)...... 32 1.8.2 Blennidae (Rockskippers) ...... 33 1.8.3 Pomacanthidae (Marine Angelfishes) ...... 34 1.8.4 The Synodontidae (Lizardfishes)...... 35 1.8.5 Gobiidae (Gobies)...... 36 1.8.7 Pinguipedidae (Sandperches)...... 37 CHAPTER 2: STUDY AREA ...... 39 2.1 The Coral Coast...... 40 2.1.2 Natural Habitats ...... 42 2.2 Environmental Issues ...... 44 2.2.1 Live Rock Harvesting ...... 44 2.2.2 Over Fishing ...... 45 2.2.3 Deterioration of Coastal Water Quality ...... 45 2.2.4 Logging...... 45 2.2.5 Coastal Erosion...... 46 2.2.6 Pollution...... 46 2.2.7 Overgrowth of Algae...... 46 2.2.8 Flooding...... 46 CHAPTER 3: METHODS ...... 48 3.1 Approach and Assumptions ...... 48 3.2 Reefs Selected as Study Units Sites...... 48 3.1.1 Votua Reef ...... 49 3.1.2 Silivaiyata Reef...... 50 3.1.3 Vatuolalai Reef ...... 51 3.1.4 Namatakula Reef ...... 51 3.1.5 Namada Reef ...... 52 3.1.6 Oria Reef ...... 52 3.1.7 Navoto Reef...... 53 3.1.8 Malevu Reef...... 53 3.3 Differences amongst reefs ...... 56 3.4 Indicators Selected for Live Rock Harvest Effects...... 56
vii 3.5 Methods Used for Sampling...... 57 3.6 Data Analysis ...... 60 3.6.1 Fish data Analysis...... 60 3.6.2 Substrate data analysis...... 62 3.6.3 Depth profiles ...... 64 CHAPTER 4: RESULTS...... 67 4.1 Fish Abundance ...... 67 4.1.1 Butterflyfish ...... 67 4.1.2: Blennie fish ...... 69 4.1.3: Angelfish ...... 71 4.1.4 Lizardfish ...... 73 4.1.5: Sandperch fish ...... 75 4.1.6: Damselfish ...... 77 4.1.7: Gobie fish...... 79 4.1.9: Summary of Fish Abundance...... 84 4.2 Substrate Composition...... 84 4.2.1 Harvested Reefs ...... 85 4.2.1.1 Malevu Reef ...... 85 4.2.1.2 Namada Reef ...... 85 4.2.1.3 Navoto Reef...... 86 4.2.1.4 Oria Reef...... 86 4.2.2 Analysis results between the four harvested reefs ...... 86 4.2.3 Non-harvested reefs...... 87 4.2.3.1 Namatakula Reef ...... 87 4.2.3.2 Silivaiyata Reef ...... 87 4.2.3.3 Votua Reef...... 87 4.2.3.4 Vatuolalai Reef...... 88 4.2.4 Analysis between the four non-harvested reefs ...... 88 4.2.5 Comparison between the four harvested reefs benthic composition and the four non- harvested reef ...... 89 4.2.6 Summary of substrate composition...... 90 4.3 Depth Profiles ...... 91 4.3.1 Non-harvested reefs...... 91 4.3.1.1 Namatakula depth profile...... 91 4.3.1.2 Votua depth profile ...... 92 4.3.1.3 Silivaiyata depth profile...... 93 4.3.1.4 Vatuolalai depth profile ...... 94 4.3.2 Analysis of the four non-harvested reefs depth profiles ANOVA...... 95 4.3.3 Harvested reefs...... 95 4.3.3.1 Oria Reef...... 95 4.3.3.2 Namada Reef ...... 96 4.3.3.3 Navoto Reef...... 97 4.3.3.4 Malevu Reef ...... 98 4.3.4 Analysis of the four harvested reefs depth profiles (ANOVA) ...... 99 4.3.5 Average depth profiles of the four harvested and four non-harvested reefs...... 99 4.3.6 Average coefficient of variation of the four harvested and four non-harvested reefs ...100 4.3.7 Summary of the depth profiles...... 102 CHAPTER 5: DISCUSSION ...... 104 5.1 General comments...... 104 5.2 Fish Abundance ...... 105 5.2.1 Fish abundance in the non-harvested (control reefs)...... 106 5.2.1.1 Food and habitat...... 106 5.2.1.2 Physical feature of individual reefs ...... 107 5.2.2 Fish composition in the non-harvested reefs...... 108 5.2.3 Fish abundance in the harvested reefs ...... 110
viii 5.2.3.1 Reduction in Fish Abundance as a Response to live rock harvest...... 111 5.2.3.1.1 Food limitation...... 111 5.2.3.1.1.0 Angelfish and Butterflyfish ...... 111 5.2.3.1.1.1 Blennies...... 112 5.2.3.1.1.2 Lizardfish ...... 112 5.2.3.1.2 Intensity of harvesting...... 113 5.2.3.1.3 Disturbance during survey ...... 114 5.2.3.1.4 Effect of depth...... 115 5.2.3.1.5 Malevu...... 116 5.2.4.0 Increase of fish abundance in response to live rock harvest ...... 117 5.2.4.1.0 Sandperch ...... 117 5.2.5.0 Fish that do not show any significant difference in abundance ...... 118 5.2.5.1.0 Gobies and Damselfish ...... 118 Damselfish ...... 118 Gobies ...... 119 5.2.6 Fish composition in the harvested reefs...... 120 5.3 Effects on benthic community...... 122 5.3.1 Comparison of the substrate composition in the four non-harvested reefs...... 123 5.3.2 Substrate composition in the four harvested reefs, responsive to live rock harvest.....126 5.3.1.0 Macro Algae and turf Algae...... 126 5.3.1.2 Crustose Coralline Algae (CCA)...... 128 5.3.1.3 Live Coral...... 129 5.3.1.5 Soft corals and others ...... 131 5.3.2.0 Abiotic factors...... 131 5.4 The effect of live rock on the reef morphology and depth...... 132 CHAPTER 6: CONCLUSION AND RECOMMENDATIONS ...... 133 REFERENCE...... 137 APPENDIX I ...... 162 APPENDIX II ...... 163 APPENDIX III...... 164 APPENDIX IV ...... 169
List of Figures List of Figures ...... page Figure 3.0: Map of the Coral Coast, Fiji with the study sites ...... 56 Figure 3.1: Sampling design on a reef ...... 59 Figure 3.1.1: Unit of sample...... 59 Figure 4.1.1: Butterflyfish abundance ...... 67 Figure 4.1.2: Blennie fish abundance...... 69 Figure 4.1.3: Angelfish abundance ...... 71 Figure 4.1.4: Lizardfish abundance...... 73 Figure 4.1.5: Sandperch fish abundance ...... 75 Figure 4.1.6: Damselfish abundance ...... 77 Figure 4.1.7: Gobie fish abundance...... 79 Figure 4.1.8: The Bray-Curtis dissimilarity dendogram ...... 81 Figure 4.2: Percentage substrate composition...... 84 Figure 4.3.1: Namatakula reef depth profile...... 89 Figure 4.3.2: Votua reef depth profile...... 90 Figure 4.3.3: Silivaiyata reef depth profile...... 91 Figure 4.3.4: Vatuolalai reef depth profile ...... 92 Figure 4.3.5: Oria reef depth profile ...... 93
ix Figure 4.3.6: Namada reef depth profile ...... 94 Figure 4.3.7: Navoto reef depth profile...... 95 Figure 4.3.1.1: Malevu reef depth profile ...... 96 Figure 5.0: Mean depth profiles of the 4 harvested and 4 non-harvested reefs .97 Figure 6.0: Coefficient of variation of the depth profiles of the four harvested and non-harvested reefs...... 98
List of Tables Table 4.1.1: Butterflyfish Frequency ...... 68 Table 4.1.2: Blennie fish Frequency...... 70 Table 4.1.3: Angelfish Frequency ...... 72 Table 4.1.4: Lizardfish Frequency...... 74 Table 4.1.5: Sandperch fish Frequency ...... 76 Table 4.1.6: Damselfish fish Frequency...... 78 Table 4.1.7: Gobie fish Frequency...... 80 Table 4.1.8: Bray-Curtis dissimilarity index ...... 82 Table 5.0: Comparison of percentage substrate composition (Z-test)...... 84
x INTRODUCTION
Live rock is dead coral rock (calcium carbonate material) that contains encrusting organisms such as Coralline Algae, other Algae, and epibenthic invertebrates (Delbeek and Sprung, 1994). It is used as partially-living substrate in creating relief or seascape in aquaria. The live part of the rock refers to the
Coralline Algae covering the surface and any fauna or flora living on or within
(Lovell and Timuri, 1999). The Algae and the bacteria components remove organic waste products such as ammonia and phosphate and act as a buffer maintaining the pH. Live rock serves as a biofiltering device, controlling the mineral cycle such as nitrogen by nitrification and denitrification processes (Falls et al., 2003). Live rock also acts as an ecological foundation in the aquaria, providing food and habitat. These are reasons for the increasing demand of the product (Parks et al.,
2003).
The live rock trade, a part of the marine aquarium industry, has stirred a lot of interest locally and on a worldwide scale. This is a result of people’s preference to have an aquarium that resembles a real coral reef system (Falls et al., 2003). Fiji is a major exporter of live rock; alongside Indonesia, it supplies 95% of live rock to the United States of America (US) (Falls et al., 2003). The amount of rock exported from Fiji has increased to approximately 1400 tonnes since live rock harvest began in 1994 (Isimeli, 2006).
The increasing demand for live rock has generated a lot of income to companies and local residents. Income to local residents comes from the access to
1 live rock on their fishing grounds used and employment for live rock harvest. The economic importance of live rock to local residents is therefore a valid one.
Concerns from environmental organizations have led to the banning of live rock harvest from the wild in several US Entities in 1997. The Gulf of Mexico, the
South Atlantic Exclusive Economic Zone (EEZ), the Caribbean EEZ, Puerto Rico,
U.S Virgin Islands, North Carolina, Western Pacific, California, Hawaii, and Guam are some of the states and territories that have banned harvesting from the wild.
Shortly after the bans, live rock export from Fiji grew five-fold within the years 1996-
1998 (Falls et al., 2003). This increase also coincided with the establishment of the
Walt Smith International (WSI), Fiji’s largest aquarium company, in the country.
According to the Marine Aquarium Council (MAC) (2003), large-scale removal of the rock can destroy habitat for fish and marine invertebrates. This would lead to decrease in reef animal abundance that relies on these for food. The coral population in reef flat lagoons (because the harvesting of the rocks also includes coral) is reduced which can result in erosion. This could imply a loss in reef rugosity or topographical diversity. Studies by leading Luckhurst and Luckhurst
(1978) have shown how loss in rugosity leads to lowered species richness. Other scientists, according to Lovell (2002), speculate that the removal of rock leaves shallow pools, which increases habitat relief and the amount of intertidal pond water, a beneficial effect. Microhabitats are important for sheltering fishes and other organisms from desiccation and predation. Whether the good consequences outweigh the destructive impacts is yet to be determined.
2 Determining whether or not live rock harvest affects the abundance of fish and substrate composition is the main goal of this research project. The reefs situated along the Coral Coast on the southwestern side of Viti Levu, Fiji, constitute the study area. This study is based on the assumption that substrate composition and fish abundance on the reef flats, where live rock harvest occurs, are responsive to the harvest and that these changes can be detected despite natural environmental variation. In the pursuit of this goal several objectives will be accomplished:
1. Compare fish abundance on reefs with a history of live rock harvest
(harvested or H reefs) to reefs with no history of live rock harvest (non-harvested or
NH reefs), to determine if a relationship exists.
2. Compare substrate composition on harvested and non-harvested reefs to determine if a relationship exists.
3. To compare the depth profiles on harvested reefs and non-harvested reefs to determine if a relationship exists.
3 CHAPTER 1: LITERATURE REVIEW
1.1 History of the trade
The following section discusses the historical literature of the live rock trade as a part of the World-wide trade to the establishment in the local market.
1.1.1 Marine Aquarium Trade World-Wide
Prior to 1986, the keeping of marine ornamentals was restricted to public aquaria and aquarium hobbyists in Europe. In Northern America publication of advances in husbandry techniques fueled the popularity of the mini-reef aquaria; these are 15 to 100 gallons in volume and house tropical marine fish, plants and invertebrates. This rise in the popularity of the mini-reef is considered to be the major factor responsible for expansion in the aquarium trade (Delbeek, 2001).
Rapid expansion in the trade has occurred since the 1980s, with massive increases in the trade of tropical marine fish and invertebrates; for example, the global trade in corals increased from 20, 000 kg/yr in 1985 to 400,000 kg/yr in 1995
(Green and Shirley,1999). In 1986, TRAFFIC (US), the American branch of the
World Wildlife Fund that tracks international trade in endangered plants and animals, estimated that there were 10 million marine aquarium hobbyists. The fastest-growing segment of the industry was the mini-reef an estimated amount spent by the North American hobbyists in 1999 for the mini-reef was some US$240 million. The global gross value of the aquarium trade in 2003 was estimated to be
US$350-530 million, that involved 1.5-2 million people. This increasing trend in the
4 trade was due to a desire of people to have aquaria in their homes (Wabnitz et al.,
2003). The other factor that has enhanced this fascination is by reef related entertainment such as the movie Finding Nemo. The trade, therefore, is largely driven by market demands.
Live rock is used in the aquarium systems because live rock is aesthetically pleasing; provides vital substrate for the settlement and recruitment of benthic organisms; acts as a natural biofilter that serves as habitat for nitrifying bacteria, protozoans ,foramineferas and Algae (Falls et al., 2003).
The demand for live rock steadily increases because of its attractive color and ecological and biofiltration values. Green and Shirley (1999) reported that there was thought to be more than 50 million kgs of live rock maintained within the US aquaria in 1999. The high demand for live rock in the worldwide market led to increases in harvesting using various destructive harvesting methods. Prior to
1997, the US was harvesting wild live rock with aid of destructive chemicals, explosives and crowbars that chip the rock into small pieces. However, a ban was placed in the Gulf of Mexico, South Atlantic and Florida State waters in 1997, due to deterioration coral reef conditions (Falls et al., 2003).
The closure of wild live rock harvest from the US waters in mid 1990 stimulated other suppliers like Fiji and Indonesia to increase exports. Fiji for example increased the exports, fivefold within a year in 1994 when it first started.
Since the 1990s the US has been the major importer of the worlds live rock market, importing about 95% of the live rock traded within the world wide marine aquarium
5 industry (Parks et al., 2003). It has been estimated that more than the reported value is imported into the US market because it is generally not reported separately from other Sceleractinian coral imports like coral rock (Bruckner, 2001). The total value of US live rock sales during the period 1992-2000 was estimated at $14 million, representing a volume of 2.5 million kg. According to Wabnitz (2003), the annual trade of live rock is about 3.9 million pieces or about 2.1 million kg. Fiji is currently the primary source of live rock to the States.
1.1.2 Marine Aquarium Trade in the Pacific Region
Fiji dominates the marine aquarium industry within the Pacific with a market share of approximately 75 percent of all trade; annual export earnings of US$19 million for the year 2001 and over 1000 individuals currently employed. Regional estimates indicate that over 150 species of aquarium fish are traded by the industry with an estimated annual number of over 400,000 individuals exported, with Fiji alone averaging 260,000 individual fish exported annually. Over 50 species of hard and soft coral are exported within the region with annual estimates indicating between 120,000 and 200,000 individuals exported. Annual live rock exports for the region are estimated at 700 million kg for 2003 with 95 percent of this originating from Fiji (Eco-Consultants Pacific, 2004).
Pacific live rock typically has a minimum of 80 percent coverage of Coralline
Algae and is considered by the North American industry to be the best quality available. Live rock is or has been exported from the majority of Pacific Island nations at one time or another. However, the export of live rock is economically
6 dependent on large volumes being shipped and therefore the industry is constrained by access to large airfreight space and regular market connections. Fiji is the region’s largest supply of live rock with the Kingdom of Tonga the next largest exporter. Several Pacific nations (e.g. Palau, Federal States of Micronesia (FSM)) have banned the removal of live rock from their reefs. It is estimated that over 14 million kg of live rock was exported from the Pacific between 1992 and 2000 and live rock exports from Fiji and Tonga alone have doubled each consecutive year from 1992-1997. In 2004, Fiji supplied 1.36 million pieces/0.92 million kg of live rock to the overseas market which was more than half of the world live rock market (Lal and Cerelala, 2005). The local mass harvesting of the live rocks for export markets caused a decline in the market price of live rock with which other countries could not compete.
1.1.3 Aquarium trade in Fiji
The aquarium trade began in Fiji in 1984 with the export of ornamental fish only. The live coral trade started in 1992 and the live rock trade started in 1994
(Singh, 2005).
In 1997, there was a concern by the cabinet ministers of the government regarding the adverse impact of the live coral trade, particularly on fish stocks. This was due to the tripling of the amount harvested within that year. Customs department was asked to monitor live coral exports. The Fiji Trade and Investment
Board (FTIB) withdrew all concession licenses until a proper study on the impact of the trade on Fijis marine life was conducted by the Department of Environment. As
7 a result, a provisional EIA report on the extraction of coral reef products for marine aquarium and curio trade was produced in June 1999 by Edward Lovell and
Manasa Timuri of the Fisheries Department.
The coalition government in 1999 agreed to form a subcommittee responsible for the various entities; Environment, Fijian Affairs, Fisheries and
Justice to consider implications of the impacts of coral and live fish and the consideration of banning the trade. The work of the committee was disrupted by the events of the 2000 coup.
In 2001 the government (SDL), decided to follow up on the issue of coral harvest after concerns raised by the tourism sector. The cabinet decided on a
“consideration for moratorium on coral/ live rock harvesting” unless a thorough study was carried out and presented to Government.
International Marine Life Alliance (IMA) was contracted to carry out the study. The study came to a pause in 2002 due a collapse in the Global IMA organization. The work resumed in 2004 and was completed in 2006 after pauses in the study. During the duration of the IMA study, the Department of Fisheries developed guidelines, which were initiated in 1983 (Lovell and Timuri, 1999) to manage the trade, this was implemented in 2005. An outcome of the policy made was not to increase the number of exporters operating in Fiji amongst other guidelines.
At the 46th Standing Committee (SC46) meeting in Geneva 2002, Fiji voluntarily proposed to reduce the trade by 50% of the level of trade that happened
8 in 2001. A quota system for live Hard Corals and live rock was implemented in
2003. The quota established in 2003 and endorsed again in 2004 was based on arbitrary figures. The arbitrary quota for live rock is half of the 2003 quota which is
1.4 million kg. In 2005, about 97% of this quota was used and for half of the year
2006, about 58% of this yearly quota has been used. The existing quota is an interim precautionary measure to ensure that the extraction from the wild for the aquarium trade is within the reasonable limits whilst a quota based on scientific data is under development.
1.2 Convention on International Trade in Endangered Species (CITES)
Fiji became a party to CITES in 1997. Countries that have joined CITES agree to be bound by the convention known as parties. There are 169 parties including the US and UK who are the main importers of live rock. Since the countries are bound by the convention, live rock exported must comply with CITES regulations. Even though CITES legally binds the parties, parties have to implement the convention through national legislation since CITES does not take place of national law. Fiji therefore, enacted the Endangered Protected Species Act
(EPS Act) in December 2002 followed by the gazettal of the EPS regulation in
2003.
The EPS Act legislates that export of species listed in the Convention will be allowed only if such export is not detrimental to the survival of the species in the wild. This measure is known as Non Detriment Finding (NDF). Species that are covered by CITES for the aquarium trades are live rock and live Hard Corals only.
9 Live coral and live rock belongs to Appendix II of the CITES listing. The species covered by CITES are listed in three Appendices, according to the degree of protection required. Appendix II includes all species not necessarily threatened with extinction, but in which trade must be controlled in order to avoid utilization incompatible with their survival.
Under the EPS Act the Fiji Islands CITES Management Authority (MA) and
Fiji Islands CITES Scientific Council (SC) was established. The Scientific council is required to advice the Management Authority on the effects of trade and on the status of the species. The functions of the Council and the Authority are stated in the Act.
The Fiji CITES MA consists of:
The Permanent Secretary (CEO) responsible for Environment as the chairperson;
The Director of Environment;
The Director of the National Trust of Fiji;
3 Government public officers (Ministry of Agriculture, the Ministry of
Fisheries and Forests and the Fijian Affairs Board to nominate one each);
2 members to represent the non-governmental organizations dealing with the protection and conservation of the environment;
10 2 members nominated by the body that represents those involved in the trade, sale, possession, exportation or importation of species mentioned in section 3 of the Act.
The Fiji CITES SC consists of the:
the Conservator Forest as the chairperson;
the Director of Fisheries;
the Director of Environment;
the Director of Research of the Agricultural Division;
the Director of Animal Health and Production;
an academic nominated by the Ministry of Education;
a representative of the non-governmental organization responsible for the conservation of the Environment.
1.2.1 Non Detriment Findings (NDF)
In July 2004, a workshop was convened by TRAFFIC and Environment
Australia and funded by the British High Commission to bring together key stakeholders to develop the NDF framework. The Director of Reef Check, Marine
Aquarium Council and representative of the CITES Animals Committee as well as representatives from the Fiji government and NGO’s were present.
11 It is the responsibility of the national government to ensure the implementation of the NDF framework. The NDF framework developed in the workshop incorporates elements such as environmental dynamics, traditional social structure and national and local economies. Coral, live rock, fish and socio economic groups were formed to develop scientific and socio economic requirements for NDF findings.
NDF framework links with Fiji Locally Managed Marine Areas (FLMMA),
National Biodiversity Strategic Action Plan (NBSAP) and resource inventories by
Department of Fisheries. The NDF framework serves as a useful model for management of Fijis marine wildlife, providing the framework for monitoring extraction and regulating trade in species which may not be listed in the CITES appendices but are of conservation concern to Fiji (Parry-Jones, 2004).
Unfortunately the NDF framework remains undefined though the workshop was an attempt to implement criteria.
Recommendations from the proposed NDF framework, working groups were set up to provide a strategy for implementation and a Quota Review Group was established to coordinate the implementation. These included resource based inventories, socio-economic studies and robust ecological studies.
1.2.2 Management
The aquarium trade is managed by the Fiji Fisheries Department in accordance with the Fisheries Act and by the Department of Environment in accordance with the Endangered and Protected Species Act (EPS).
12 The Fisheries Department issues fishing licenses to harvesters and monitors shipments according to national quotas for each commodity. Fisheries also chair the Fiji Marine Aquarium Council (FMAC) which includes traders, government and non-government representatives. This group meets regularly to discuss issues of concern. Exporters are also encouraged to comply with guidelines which were developed in consultation with all stakeholders involved in the trade. The
Department of Environment issues export permits and management decisions are made by the CITES scientific and management authorities with regards to sustainability of the trade.
In addition, a lot of collaborative work is carried out with NGO’s like Marine
Aquarium Council (MAC), World Wildlife Fund (WWF), Foundation for the South
Pacific People (FSPI), University bodies like the Institute of Applied Science (IAS) and industries, to enhance the management and viability of the trade. Ideas are shared to build a sustainable and credible aquarium trade.
The other existing group is the Marine Ornamental Traders Association
(MOTA) that meets every month. MOTA is made up of four industry members
(traders). Concerns and issues regarding CITES requirements and constraints that the industries face are highlighted in meetings.
1.3 Live rock trade in Fiji
There are currently 4 companies operating in 25 customary owned coastal waters (I qoliqoli), around Viti Levu and the islands off the Western Division of Fiji.
Of these, Walt Smith International (WSI), Oceans 2000, Waterlife Exporters and
13 REL are the major exporters of live rock. There are about 1000 people employed by the aquarium trade in Fiji, and more than half are employed by the live rock industry. WSI is the largest live rock exporter, supplying more than 50% of rocks from Fiji and employing about 500 people. The total amount of live rock exported from Fiji in 2005-August 2006 was 2.2 million kg valued in FJ$12 million. However the number of rocks harvested from the reef flats is much more than the export figures because there is an estimated 50% rejection rate of rocks (MAC, 2003).
The live rock harvesters are villagers contracted by an exporter paying the local entity for harvesting permission. Local members of the I qoliqoli harvest live rock on the basis of a supply contract or by indigenous Fijians employed directly by the exporters. Supply contracts are usually informal arrangements where exporters provide a licensed collector a purchase order. The license holder represents the team who is trained in the removal of the reef rock. The quantity of rock required is specified daily. It is purchased by the kilogram from the collectors minus any material that is rejected as unsuitable as only a good Coralline Algae cover is accepted. A group of villagers would make about 4 trips daily and collect about
1500 pieces/1016 kg on average per day depending on the demand.
Collection of live rock on fringing reef flat is removed from around the edges of the reef patches within the shallow lagoon water or along the outer algal flat. At other places such as barrier reef lagoons, the rocks are collected from lagoons where they have been deposited. The removal strategy depends on the nature of the reef flat where both abundance and ease of extraction are considered.
14 The process involves the removal of blocks of rock with a diameter on the order of 10-20cm. The rock is chosen on the basis of the presence of the pink to dark purple Coralline Algae on its surface or within its cavities (this is known as collectable live rock). The rock is removed using iron bars, by breaking it from the reef; it is stockpiled and then loaded on a bamboo bilibili raft for transport ashore.
Not all rocks are taken ashore as some of the rocks with low Coralline Algae cover or poor coloration (light purple in color or not according to demand) are rejected by the collectors on site. This occurs in cases where there is a thick growth of the algal species of Sargassum covering the rock, which only allows collectable rock to be recognized after it has been broken off and removed from the reef. The rocks which have about 70% coloration which is maroon or deep purple are chosen onsite and taken to warehouse for further assessments and curing.
Once removed from the reef flat, there are two strategies in preparation for trans-shipment. One is the cleaning of the rock in the near-shore shallow water and the weighing and packaging of the material on the beach for direct shipment to the airport. The other is to collect the rock with some cleaning on-site and transport it to a holding facility where further cleaning occurs and a process called curing is employed. Cured rock is material which has been placed in a holding facility where it is kept moist by a fine spray of seawater. The objective is to keep the Coralline
Algae alive while the less hardy organisms die and are washed from the rock by the water spray. The cured product is considered of a much higher quality as it is less likely to foul the aquarium system. Rock, which is shipped from Fiji directly from the
15 beach, will have to be cleaned or cured to some degree before it enters the aquaria of retail customers (Lovell and Timuri, 1999; Lovell, 2001).
The labor force for live rock collection is drawn from a number of families who alternate in the work force, these are trained personnel. Villagers receive an average price of about FJ$0.80 for a kg of live rock. This price is controlled by the exporters, which the local resource owners regard as high. However the price on the overseas market depends on freight charges which could come to about US$5 per kg. This however takes into account the freight charges and transportation costs. The exporters often target the maximum amount of live rock they can ship because freight permits costs drop with volume but increase with quantity (Lal and
Cerelala, 2005).
Apart from the income earned by collectors where they can earn up to about
FJ$21,771 per annum, the resource owners is paid for the customary rights and goodwill gestures. For example Walt Smith International paid chiefs FJ$2000 for an annual permit for their fishing grounds and the use of their divers (Lal and Cerelala,
2005). It should be noted these are published figures, and this raises question whether harvesters really earn this much and there is considerable evidence for much higher “goodwill” payments.
1.4 Previous Studies on Live Rock
The next sections discuss previous research that has been conducted regarding live rock.
16 1.4.1 International
When live rock was banned in the US territories, there had been no proper research done on live rock. There had been concerns however on effects in general of the harvest on decline in fish abundance, increased coastal erosion, removal of fish habitat and reduction in reef structure (Ehringer and Webb, 1993).
The sensible alternative was to look into aquaculture of live rock. Therefore non-Fiji studies which related to live rock harvest have been aquaculture oriented.
Initial study of live rock centered on the recruitment of benthic organism to the rock that was monitored for the gradual attachment of organisms over time.
The density of the fish and organism depends on how big the farm is- the bigger the scale, the more the organisms. Ehringer and Webb (1993) completed the first U.S research, “Assessment of Live Rock Harvesting in Tampa Bay”. They reasoned that as the rocks are placed in water, growth of organisms undergo succession stages much like growth on any other pioneer substrate. This assumption was supported by an assessment of live bottom communities in Tampa Bay
(Derrenbacker and Lewis, 1985). Depending on environmental conditions such as salinity, temperature and turbidity, a variety of life forms would be expected on the rocks contingent upon where the rocks were placed within the bay, and during which successional stage they were removed. Comparisons were made between live rock and artificial reefs.
Mook (1980) stated that more species would be found on the rock near the mouth of an estuary than in the upper region estuary because of variance in
17 salinity, with consideration also being given to stability of other parameters.
Estevez (1985) stated the same factors were true for Tampa Bay.
Dean and Hurd (1980) found four sessile organisms on the rock: barnacles, hydroids, polychaetes and mussels. Estevez (1985) listed the following groups of invertebrates for Tampa Bay: seafans, sea whips, hydroids, anemones, tunicates, bryozoans and Hard Corals. Santos and Simon (1980) showed great seasonal variation in species abundance and diversity of organism in Tampa Bay with the least colonization occurring in the months from September through February.
Therefore the seasonal timing for the placement of rocks may be of great importance.
However, according to The Gulf of Mexico Fishery Management Council reports in 1994, the collection of live rock from the Gulf of Mexico coastal waters resulted in the removal of the equivalent of two patch reefs each year (Falls et al.,
2003)
1.4.2 National
In Fiji most studies are unpublished and have focused on the effects of live rock harvest. An assessment of the live coral and rock extraction fishery at
Muaivuso I qoliqoli was conducted in 2000 (Sauni et al., 2003); these results showed significant differences in habitat health between reef biotope in live rock and live coral harvested and non-harvested sites. There were no significant differences in fish abundance between the two sites. The study however did not separate live rock from live coral removal impacts specifically. Coral is different
18 from live rock thus; the impacts of removal are not the same. There was also lack of understanding of the history of collection in the study site. The study remains unpublished.
In the pilot study Sykes (2001) conducted an environmental impact on harvesting live coral and live rock for the aquarium trade. This was a report commissioned by the Fiji Hotel Association, and the result of a short survey, regarded as a “snapshot” of the current state of reef health in the pilot study. The study recommended a larger monitoring program to give reliable scientific data on the exact effects of live rock extraction.
International Marine Alliance (IMA), in 2002, began a project to quantify the extent of live rock harvest and impact to the resources, with the intent to develop recommendations that would ensure that harvest is sustainable. After a lapse of 2 years, in 2004 the study was followed up and completed. Results on the analysis of live rock mining in Fiji indicated that some 270 hectares of reef have been used for live rock mining since 1992, at the rate of around 30 hectares of new reef currently being targeted for live rock mining each year. The study indicates that live rock harvest is detrimental and unsustainable. However, there has been a lot of criticism of the study, mainly regarding the lack of scientific replicable method used. (Why,
2004)
Wesson (2003) conducted a study as part of a thesis with the University of
Newcastle, the impacts and management of the marine ornamental trade of live rock in Fiji. Two different harvesting regimes at 4 harvested sites were compared to
19 1 control site. Results were confounded for the effect of live rock harvest but suggested that there were significant differences in substrate components between the control and the harvested site due to the two different techniques employed in harvesting.
The University has had students conducting post graduate work on live rock:
Fiu (2003) conducted her master’s (MSc) degree on the “Impact of live rock harvest on benthic assemblages on the reef flat”. There have been no conclusive results from this study as it continues to date. Kaur (2005) conducted a one year (2003-
2004) MSc on “Aquacultured live rock- hastening the process of colonization of artificial substrate". The results obtained from this experiment described the spatial and seasonal variations in the recruitment pattern of the crustose Coralline Algae.
Habitat comparison regarding growth of corallines; at which site and during which month the recruitment of Coralline Algae was the highest. The Crustose coralline recruits on the settlement plates were not mature enough and did not show morphological characteristics, so the genus of the Crustose Algae could not be determined. As part of a post graduate course Movono (2004) conducted a study on “The impact of the live rock trade on indicator fish species (Chaetodonidae and
Blennidae)”, a pilot study at USP, March-May 2004, which provided background for this research .
In response to the growing international concern on the destructiveness of coral harvesting in exporting countries, WWF-South Pacific took an active interest in the local aquarium trade, in Malomalo village. This was one area in which live- rock had been harvested since the early 1990s. In 2003, WWF embarked on a
20 CAMP certification project with MAC as this was seen as an appropriate mechanism for establishing and supporting the sustainable collection of aquarium products. Prior to this was socio-economic and biological monitoring of the
Malomalo collection area to provide information before actual certification. This was also in conjunction with the Locally Managed Marine Area (LMMA) in declaring
“tabu” no extraction areas (Susau et al, 2003)
The Marine Aquarium Council (MAC), in collaboration with the University of the South Pacific and consultants, has developed methods of monitoring live rock harvest in 2004. This has led to resource assessments on several of the harvested sites in Kalokolevu and Vatukarasa in 2005 (MAC, 2005). The Institute of Applied
Science (IAS) also conducted monitoring following the developments of monitoring methods in 2004 and 2005 on the impacts of live rock harvest. However the experimental design of the IAS monitoring did not take into account the effects of fishing and the history of live rock harvest at the sites (Reynolds et al, 2005).
Lal and Cerelala, (2005) conducted a study for SPREP and Foundation for the South Pacific People Initiative (FSPI) on the financial and economic analysis of wild harvest and cultured live coral and live rock in Fiji. They found out that it is possible to replace wild harvest with cultured rock after several years of gradually phasing out wild harvest live rock.
A considerable amount of work has been done on live rock, however the question that fails to be answered and a concern by the communities (Owen, 2003) is the ecological impacts. The ecological role of live rock has to be understood to
21 realize the extent of the impact of harvesting on village livelihood regarding fish and invertebrates which are important to the subsistence and artesinal fishery.
1.5 Coral Reef Communities
Coral reefs are the second most diverse ecosystem in the world and have been the model for some of the most important work in ecology (Hodgson, 1998).
They are renown for their diversity, not only in terms of species but also particularly because of the occurrence of representatives of most extant phyla. They are an economically valuable food source and their chemical compounds have pharmaceutical importance. Coral reefs control sediment transport processes, protect coastlines from erosion, help create sheltered harbors, and facilitates the development of shallow basins with associated mangrove and sea grass communities (Wood, 1999). They support a diverse range of flora and fauna as the primary productivity on coral reefs is amongst the highest in the marine communities (McClanahan et al., 2000).
In the Pacific, coral reefs are regarded of high importance. People rely on the reefs for their daily living, food, money and other traditional and medicinal uses
(Vuki et al., 2000). In Fiji, coral reefs are an important part of the Fijian identity as each indigenous tribal unit is allocated a fishing ground (I qoliqoli) or a reef where they can fish. Every tribal unit also has a fish as a totem signifying the intimate connection of mankind to their fishes/nature.
However, with an increasing population and modernization, anthropogenic disturbances have deteriorated the coral reefs. Pollution, elevated nutrient levels,
22 overfishing, coral and live rock harvesting are examples of such disturbances
(Thaman et al., 2002). An understanding of the coral reef ecology is needed to have a holistic idea of the extent of damage caused by such disturbance.
In this scenario, the impact of live rock harvesting can only be understood if live rock is understood and all its components including the role in the coral reef community. The live rock community is part of the benthic microflora, periphyton and plant association in the coral reef community. The Coralline Algae, being the main component of live rock (60- 80%) needs to be reviewed carefully.
1.5.1 Benthic microflora, periphyton and plant associations
The plant benthic communities and the bottom micro flora are responsible for more than half the total autotrophic production and of heterotrophic metabolism in coral-reef ecosystem (Clayton and King, 1990). The plant benthic communities have been described by Sorokin (1993) into three categories and their respective microbial associations. The microphytobenthos of soft sediments are represented by bacteria in soft sediments (soft Sands) and by bacteria in the detrital sediments.
The periphyton overgrowth of the solid surfaces and Rubble (which live rock is a part of) is associated with the periphiton bacteria. The thallophyte seaweeds/seagrasses are associated with the bacteria symbiotic to benthic animals such as sponges (Sorokin, 1993).
23 1.5.2 The periphiton communitiy/ live rock communitiy
The periphiton community which is the live rock community has been described by Sorokin (1993) in detail. The periphiton turfs, which are about 2-5cm in thickness, are vast surfaces of pourus lime reef rocks (Rubble) that is densely overgrown with Algae. They are structured like microhabitats or micro-bieonoses, which unite the autotrophic and heterotrophic components in one mucoid structure
(Sorokin, 1993).
The components contained are different types of bacteria and Algae, ciliates and Foraminiferans as well as other microbenthic animals. The microflora in the periphiton communities contains attached or chain forming bacteria. The single celled bacteria are numerous being attached to the surfaces of Algae with the aid of their stalk.
The plant communities of the periphiton turfs Algae include small thalloms of macrophytes, crustose Coralline Algae, filamentous and attached micro Algae. A significant part of the benthic plant communities of coral reef biomass is represented by crustose Corallinaceae. Corallines are able to inhabit poor light conditions such as caverns which are an advantage of the red Algae over other
Algae making them more diverse and abundance. The brown and green macroalgal species are well represented. The filamentous Algae include the green
Algae and cynobacteria.
24 The microbenthic heterotropihic part of the periphiton communities include ciliates represented by Vorticella, benthic Hypotricha, small Nematods and
Foraminifera
1.6 Importance of live rock
The role of live rock in the periphyton community has been well established, however the following paragraphs relates the vital role played in physical,bio chemical and ecological processes .
1.6.1 Calcification
Coral reefs are structures formed by calcium carbonate extracted from the sea almost exclusively by living organisms, a process called calcification. The primary roles of corallines are calcification and association with the periphiton community (Sorokins, 1993). They are important organisms on coral reefs as cementers and builders of carbonate material (Keats et al., 1997). Coralline Algae mount and cement the reefs constructions in the most stressed zones producing bulks of hard calcareous material (Adey and Vassar, 1975). In the process of photosynthesis, the Coralline Algae fix carbon for physiology and for the calcification processes (Borowitzka, 1983). The calcium is deposited in the cell walls of the Algae in the form of calcium carbonate, which is not used by the Algae but is reef building (Death and Fabricius, 2001).
The algal ridge on the reef crest is an area where the coralline is particularly important in constructing reef framework (Vroom et al., 2006). This algal ridge
25 require high and persistent wave action to form, so are best developed on the wind- ward reefs in areas where there little change in wind direction (Keats et al., 1997).
These ridges are one of the main reef structures that help prevent coastal erosion.
This area and the outer reef flat are where the live rock is being harvested.
1.6.2 Biogeochemical cycle
One of the main features of the periphiton communities which are vital to the functioning of the coral ecosystem is the microbial degradation of organic matter.
The nitrogen fixing bacteria and denitrifying bacteria regulate the nitrogen cycle which is supplied by oceanic waters and rivers (Segar, 1998). These provide a positive balance of nutrients and organic matter in marine environment during bacterial interaction with surrounding ocean (Sorokin, 1993). This is also one of the main reasons live rock is harvested to promote ecological balance in the aquaria.
Sorokin (1993) further states that the periphiton microflora being a site of microbial degradation in coral reefs, could have a global importance for the turnover of
Dissolved Organic Matter (DOM) contained in oceanic waters.
1.6.3 Photosynthesis
About 40-80% of primary productions in the coral reef ecosystem come from benthic plant associations (Borowitzka, 1983). Experiments by Sorokin (1993) also show that the periphiton communities are amongst the most active metabolizing compartments of a reef system. In the process of photosynthesis, the Coralline
Algae takes in carbon as CO2 and gives off oxygen, an essential to animal life in the marine ecosystem.
26 1.6.4 Habitat and food source
Coralline Algae are a source of primary food production for herbivorous grazers such as blennids and scarids (Addey and Vassar, 1975). Harmelin-Vivien et al. (1989) have shown that periphiton turfs are one of the main sources of feeding for herbivorous invertebrates and fish. The periphiton Algae are grazed by numerous surgeon fish, Scarids, Chaetodons, as well as by crabs, shrimps,
Gastropods and Urchins (Sorokin, 1993). The Epithilic algal matrix (EAM) is also a part of periphiton community of which 10% to 78% is detritus, serving as major food source for many fish species (Wilson, et al, 2003). Sorokin (1993) also states that the high biomass and production of epithilic algal and bacterial turfs provide quick restoration of food sources for these important groups of reef animals.
Some Coralline Algae develop thick crusts, which provide microhabitats for many invertebrates, (which is also part of live rock) such as Urchins, Chitons and
Limpets. On a community level this is important for fishes which rely on the invertebrates as a food source.
The chemicals produced by the Coralline Algae promote the settlement of the larvae of herbivorous invertebrates such as abalone (Daume et al., 1999). This also benefits the coralline since the herbivore removes the epiphytes, which could smother the crusts and reduce available light. At the community level, the presence of invertebrates associated with corallines can generate patchiness in the survival of young stages of dominant seaweeds. The sloughing of the epithelial
27 layer of some coralline has anti-fouling effects, which also enhances herbivore recruitment (Keats et al., 1997).
1.7 Disturbance on coral reef communities
The combined forces of nature like storms, cyclone, tsunami, Crown of
Thorns (COT) outbreaks along with human intervention all appear to be bad for coral reefs (Bellwood et al., 2004). Disturbances may have a range of effects including the loss, fragmentation and/or degradation of preferred habitat, which may affect fish species in different ways (Lewis, 1997). The physical attributes of the reefs, whether perturbed by man or naturally is influential in the fish abundance and species composition on each reef. The impacts of physical disturbances are generally much greater than those of biological disturbances, highlighting the importance of topographic complexity and live coral cover in supporting reef fishes. These factors could ultimately affect fish behavior and alter fish composition of a reef.
Several studies have established how fish and substrate have been responsive to disturbance on coral reef communities. These are naturally induced disturbances as well as anthropogenic ones. Hoegh-Guldberg (1999) and Moran (1986) have described the effect of coral bleaching and Acanthester planci outbreak causing a widespread loss of live coral cover and algal proliferation. Pratchett et al. (2004), have indicated how sub lethal bleaching affected the physiology of butterflyfish, but not immediate abundance suggesting this would lead to declines in future population. Rogers (1990) discusses how coral reefs and organisms are sensitive to sedimentation. A combination of
28 disease, pollution and overfishing are implicated as the most likely cause of coral reef degradation (McClanahan et al., 2001). Furthermore, during severe tropical storms and direct physical perturbation, there is an immediate reduction in both live coral cover and complexity of reef framework (Lewis, 1997). Gratwicke and
Speight (2005) stated that habitat complexity is important for species. The effects of coral mining in the Maldives have been investigated in several studies. The biological and physical impacts of coral mining on reefs in Malé Atoll, Maldives were investigated by Brown and Dunne (1988). They reported that live coral cover on reefs subject to coral mining was very low compared to unmined reefs.
Response to reef associated fish to coral mining was reported by Shepherd et al.
(1992) and Brown et al. (1990). They have shown that there were two principal effects of coral mining on reef fish communities, which were, the loss of live coral correlated to loss in fish abundance and the reduction in rugosity which have been reported to reduce species richness.
A few researches have been conducted to investigate into the relationship of the benthic communities and fish association. Pranovi et al. (1998) have looked into how anthropogenic perturbations have reduced the benthic population and have temporarily changed the environments biotic and Abiotic features. In Robert and Ormond (1987) investigations of habitat cover and reef fish species of the Red Sea, they correlated the substrate diversity to species richness. Most studies have correlated fish abundance and richness to coral cover (Bell and Galzin 1984, Chabanet et al.1997, Garpe and Ohman 2003).
Ault and Johnson (1998) have shown a correlation of fish composition and
29 richness to the substrate in a contiguous reef type, this however is not applicable to patch reef types.
1.7.1 Reef Fishes in coral reef communities
Coral reefs which cover only 0.09% of the ocean are the habitat of approximately a quarter of all fish species (Sale, 1980)). Fishes are the most conspicuous, diverse and well studied groups of organisms that are closely associated with coral reefs. For the large part, they are dependent on coral reef communities for vital resources such as food, shelter and living space, the requisites for survival and reproduction (Jones and Syms, 1998). Some fishes may be associated with biotic features of the habitat such as corals or sponges, while others are more associated with the topographical complexity of the reef, occupying caves, holes or crevices (McCormick, 1994). The abundance of individual species and the structural and functional community should, thus, be very sensitive to disturbance-induced changes in habitat structure (Gratwicke and Speight, 2005).
There have been several studies dealing with factors affecting fish populations. Factors that influence the distribution pattern and community structure of inshore fishes are difference in physical factors between habitats
(Blaber and Blaber, 1980), difference in structural heterogeneity and thus shelter from predation between habitats (Heck and Orth, 1980), difference in food availability and productivity between habitats (Odum and Herald, 1975) and water clarity (Blaber and Blaber, 1980). Reef fish species vary from small population that may be associated with a single coral species to those that may be found almost everywhere (Munday et al., 1997) According to Vazquez and
30 Simberloff (2002), the theory is that the susceptibility to disturbance may largely be determined by where most fish lie, between the extremes of specialization and versatility. This implies that specialized environments which cater for only specialist feeders, when disturbed will affect certain species that rely on that. However environments that provide food source for various versatile feeders, when disturbed will affect more range of species. The live rock community could in this case be affected by the disturbance because it provides a wide range of foods and habitat for fishes from detritus to Algae.
To understand the impacts of habitat-disturbance on fishes we need to understand not only the specific habitat requirements of the fish, but the ways in which the different disturbance affect the biological and physical structure of the substratum (Wilson et al., 2006).
1.8 Indicator Fish species
The concept of using certain key species as indicators of ecological condition is now well established (Crosby and Reese, 1996). For an indicator species, an extensive knowledge of the ecology, behavior of the fish is vital
(Schiemer, 2000).
The seven families used as indicators for this study will be briefly described.
Chaetodonids (Butterflyfish), Blennidae (Rockskippers), Pomacanthidae (Angelfsh),
Synodontidae (Lizardfishes), Gobiidae (Goby), Pomacentridae (Damselfish) and
Pinguipedidae (Sandperches) are appropriate indicators of the impact of the live rock harvest because of their intimate relationship with live rock (periphyton)
31 community. These chosen fishes are common reef fish which can be found on the reef flats all year round.
1.8.1 Chaetodonids (Butterflyfish)
Fishes of the family Chaetodonidae, the Butterflyfishes, are found in all tropical seas of the world (Reese, 1996). There are 114 Species in 10 Genera with
90 of the Species in the genus Chaetodon. Butterflyfishes are characterized as diurnally active, brightly colored inhabitants of coral reefs (Michael and Woodward,
1994). They belong to three feeding groups: corallivores, benthic omnivores and planktivores (Pratchett et al., 2006).
Reese (1996) recommended that the corallivores Chaetodon as being a good indicator of coral reef health because of the direct dependence of food on the coral. However for live rock studies omnivorous Chaetodon are also chosen because they feed on the benthic invertebrates and Algae associated with the live rock
Chaetodons are territorial fishes in which males are usually the defensive ones. There is an associative mating pair bond formation based on size.
Butterflyfish are dusk spawners on evenings and full moon. Chaetodon pairs show a very high degree of site fidelity with the same individuals being found on the same territories for seven to eight years. Their life span is 10 to 12 years depending on the species. Predation is minimal on adults but occurs on larval stages. Their striking colors make them ideal for observations in the field. Hence, all these
32 characteristics make them ideal candidates for indicator species of ecological conditions on coral reefs. (Reese, 1996)
1.8.2 Blennidae (Rockskippers)
Blennids are a member of fishes of the family Blennidae that was formerly placed in the family Gobiidae. All of the fish are elongated, generally bottom dwelling fish with long anal and dorsal fins and prominent eyes (Thresher, 1980).
They are cryptic and largely territorial fish (Sale, 1980). Due to their behavior, feeding habits and habitat, Blennies make a good indicator the impact live rock removal.
Blennies are one of those reef fishes that are strongly site attached living in holes and burrows on the reef (Lowe-McConnell, 1987). Reasons for this behavior includes defense for space, food, mates, spawning sites and offspring. They are mainly herbivorous and depend largely on Algae for food (Townsend and Tibbets,
2000). Some researchers (Wilson, 2001) have stated that classifying blennies as a herbivore is often misleading and more specifically regard Blennies as Epithilic
Algal Matrix (EAM) feeders. This is largely due to the investigation of their stomach contents in which mixtures of detritus, Algae and inverts was found (Wilson, 2002).
The presence and absence of their microhabitats influence the distribution of
Blennies as previously studied by Townsend and Tibbets (2000).
33 These fishes are vigorously territorial (Thresher, 1980). Each of these fish defends an area of about 1.5- 2sq meters chasing off other fishes. Periodically
Blennies patrol their territory moving from one high point to another. If the fishes are carefully approached carefully, despite being cryptic, one can see about 6-7
Blennies on one microhabitat (Lowe-McConnell, 1987). On high tide, each fish would defend a single preferred hole. For these reasons Blennidae would make an appropriate indicator species.
1.8.3 Pomacanthidae (Marine Angelfishes)
Marine Angelfish are a type of perciform fish of the family Pomacanthidae.
They are found on shallow reefs in the tropical Atlantic, Indian, and mostly western
Pacific Ocean. The family contains seven Genera and approximately 86 Species
(Alevizon, 1994).
With their vibrant colours and deep, laterally compressed bodies, marine angelfishes are some of the more conspicuous residents of the reef. They most closely resemble the Butterflyfishes, a related family of similarly reef fish. Marine
Angelfish are distinguished from Butterflyfish by the presence of strong preopercle spines (part of the gill covers) in the former (Debelius et al., 2003).
While the majority adapt easily to captive life, some are specialist feeders which are difficult to maintain. Feeding habits can be strictly defined by genus, with
Genicanthus species feeding on zooplankton and Centropyge preferring filamentous Algae. Other species focus on sessile benthic invertebrates; sponges, tunicates, bryozoans, and hydroids are staples (Michael, 2004).
34 They are diurnal animals, hiding amongst the nooks and crevices of the reef by night. Some species are solitary in nature and form highly territorial mated pairs; others form harems with a single male dominant over several females (Allen et al.,
1998).
Due to their physical, feeding and behavioral characteristics, Angelfish are ideal indicators for live rock harvest.
1.8.4 The Synodontidae (Lizardfishes)
The Synodontidae or Lizardfish Family has 40 species, of which 31 are of the genus Synodus, five of these reside in the eastern Tropical Pacific (Randall et al., 1997).
The Lizardfishes have slender cylindrical bodies, pointed “lizard-like" heads with large mouths that have many rows of fine teeth (Nelson, 1994). They are sedimentary bottom dwellers found sitting motionless, perched on their pectoral fins, or buried in the Sand with one eye exposed, waiting to ambush unsuspecting prey. They are voracious predators feeding primarily on small fishes, krill, squid, and shrimp. Observations of Lizardfish in the aquarium show that surface area is more important than water volume because most of their time is spent resting on the bottom of the aquarium (Scott, 2005).
Although Lizardfish are not as conspicuous as Butterflyfishes and
Angelfishes, their reliance on bottom substrate would make them ideal candidate for live rock harvest indicator. The theory is that live rock removal cause’s
35 disturbance to substrate; hence bottom dwelling fish would be good indicators of the impact.
1.8.5 Gobiidae (Gobies)
The gobies form the family Gobiidae, which is one of the largest families of fish, with more than 2,000 species in more than 200 genera. Most are relatively small, typically less than 10 cm (4 in) in length (Delbeek & Sprung, 1994)) they are of great significance as prey species for commercially important fish like cod.
Several gobies are also of interest as aquarium fish, such as the bumblebee gobies of the genus Brachygobius. Goby fish is not exploited by humans for food due to their small size.
Gobies occupy coral reefs where Sand and Rubble are interspersed because they feed on Sand-dwelling micro-invertebrates, epilithic algal mats and
Algae, and use crevices to hide from predators. They have a limited home range and short life cycle (Hernaman and Munday, 2005). A study by Steele and
Forrester (2005) showed that Gobies were largely dependent on crevices for protection from predators. Thus the theory that live rock provides the crevices for the goby fish suggests that gobies will be impacted to some extent by the removal of live rock. Due to the limited home range and reliance for live rock, Goby fish would possibly make a good indicator for live rock removal.
1.8.6 Pomacentridae (Damselfish)
36 The family Pomacentridae comprises 321 species (Allen, 2001). The average size of such Damselfish is around 3 inches (8 centimeters) (Delbeek &
Sprung, 1994). They are all marine fishes, however, a couple of species are regularly found in the lower stretches of rivers in pure freshwater, and usually have bright colours (Alevizon, 1994).
Some species of Damselfish are hardy species and are able to tolerate a wide range of harsh environmental conditions. Others such as the white-spotted damselfish are not as hardy. The diet of Damselfish is wide-ranged, from small fish to Algae depending on the genus. Some are considered benthic carnivores of small invertebrates and fishes. The diet of other Damselfishes can include small crustaceans, plankton, and Algae. Behaviorally they are territorial and haremic
(Alevizon, 1994).
1.8.7 Pinguipedidae (Sandperches)
The family Pinguipedidae includes six genera, about 50 of which are marine species and one freshwater species (Alevizon, 1994).
Sandperch are bottom-dwelling carnivores and rely on small fishes and invertebrates. They inhabit open Sand and Rubble bottoms. They consume invertebrates such as bristle worms, small mantis shrimps and xanthid crabs.
Small Sandperches have been known to eat feather duster worms and Christmas tree worms. Larger individuals may consume small bivalves, anemone crabs, cleaner shrimp, anemone shrimp, pistol shrimp, small boxer shrimp, juvenile brittlestars, serpent stars and small fishes (Scott, 2005)
37 They can be aggressive toward other bottom-dwelling predators, especially those with a similar body shape (e.g. gobies). Aggression is also likely to occur between Sandperches of different species (Randall, 1997).
Their reliance on food and Sandy bottom makes Sandperches an ideal indicator for live rock harvest.
38 CHAPTER 2: STUDY AREA
Fiji is located in the Southwest Pacific Ocean at latitude of 150 –200 south and longitude 1770 west to 1740 east. It is a vast archipelago centered on two relatively shallow geological features, the Fiji Platform and the Lau Ridge.
Geologically, the area lies on the Indo-Pacific plate close to the boundary with the Pacific plate, in an area of relatively complex geology and fracturing. The two largest islands of Viti Levu and Vanua Levu, together with a large number of smaller ones, lie on the relatively shallow Fiji Platform. The country is made up of approximately 844 volcanic islands and is dominated by the Viti Levu and Vanua
Levu platforms which account for 87% of the total land area. Fringing, barrier and nearshore reefs surround most of Viti Levu, with the largest continuous fringing reef along its southern shore (Vuki et al, 2000).
Figure 1: Map of the Fiji Islands
39 (http://www.nationsonline.org/oneworld/map/google_map_Suva.htm. 12/07/2007, 2.06pm)
2.1 The Coral Coast
The Coral Coast is situated on the southwestern coast of Viti Levu and is the longest chain of fringing reefs in Fiji. The well-developed fringing reefs of the
Coral Coast extend almost unbroken for 63 km and have a seaward extension of
500 to 1000 meters. These fringing reefs protect the mangrove-fringed bays and pocketed Sandy beaches. This coastal environment has been subject to rapid
Figure 2: The map of Viti Levu showing the Coral Coast situated on South Western side of the island
40 (http://www.nationsonline.org/oneworld/map/google_map_Suva.htm. 12/07/2007, 2.06pm ) changes during storm surges. Recurrent cyclones usually come from the North
West direction.
The Coral Coast encompasses the coastal areas of the Nadroga-Navosa provinces from the village of Namatakula through to the Fijian Hotel at
Rukurukulevu village (Thaman et al., 2002). Sigatoka town is the main commercial centre for coastal and inland residents in the area. Inland residents live mainly along the Sigatoka River that is about 80 km long. Sigatoka’s population in 1996 was 7,862 increasing by 5.1% since 1986 (Fiji Bureau of
Statistics, 1998). The town also houses the provincial government, hospital and several primary and secondary schools.
The Coral Coast has a number of physical characteristics which includes a mild climate, a variety of natural habitats, and a number of interesting natural and cultural features.
2.1.1 Climate
Air temperature is relatively consistent due to the ocean temperature ranging from a low of 18oC during the coolest months (July-August) to a high of
32oC during the warmest months (January and February). Rainfall is highly variable and mainly orographic often falling in heavy, brief local showers. In addition, Fiji experiences a distinct wet season (November to April) and a dry season. Annual rainfall for the area is expected to be between 2000 and 3000 mm. The predominant winds are the trade winds from the east to southeast,
41 which are generally light to moderate in strength. Tropical cyclones which occur from November to April can cause high winds and have caused widespread damage in the area in the past (Pitman et al., 2001).
Storm surges which are temporary elevation in sea level rise caused either by very low atmospheric pressure or the piling up of water against a coast driven by strong winds (both associated with cyclones), occur on the Coral
Coast. The most recent was in early 2001 after tropical cyclone Paula resulting in winds attaining speeds up to 90knots. This resulted in flooding and damage of coastal areas due to a storm surge.
2.1.2 Natural Habitats
The well-developed fringing reefs of the Coral Coast extend almost unbroken for 63 km and have a seaward extension of 500 to 1000 meters. The only major gap is at the mouth of the Sigatoka River. Where creeks descend from the hills the reef is broken by passages of 100 to 300 meters across. The fringing reef has a shallow tidally submerged platform, usually called a reef flat, which is interspersed with moats and channels. Beyond the platform is a consolidated reef crest. The shallow lagoon-like nature of the reef flat allows for snorkeling at high tide. Morton and Raj (1980) have described the reefs at Cuvu,
Korolevu, Namatakula, Komave and Malevu in detail.
White carbonate Sand beaches back the reefs. The unconsolidated sediments making up the beaches are a mix of terrigenous, calcareous and other shallow water marine sediments. Active Sand transport is mainly to the west along the Coral Coast carried by longshore drift (Pitman et al .2001).
42 At the mouth of the Sigatoka River and other river mouths along the coral coast, terrigenous Sands have built up into high dunes.
Along the Coral Coast the lagoon is fairly narrow with the 200-meter isobath being only about 1 km offshore. Average depth of the lagoon is around 2 meters making it suitable for swimming, snorkeling, and fishing. Bathymetric surveys conducted by SOPAC indicate that the passages can attain depths of around 200m that drop at around 800 meters offshore (Manoa, 2006). Water temperature is always above 20oC with summer maximum around 30oC. Tides are semi-diurnal with neap tides having a mean range of 0.9m and spring tides
1.9m (Ryland, 1981).
Marine water quality is associated with terrestrial and anthropogenic sources, where elevated nutrient levels occur around these areas. Studies by
USP conducted in the lagoon offshore from the Outrigger Resort indicate that nutrient levels often are higher than acceptable limits and faecal coliform levels at times may exceed acceptable levels after heavy rains, especially at the mouths of creeks and near shore waters (Mosley and Aalbersberg, 2003).
Mangroves at present are located adjacent to only a few villages to the east of Sigatoka town. The mangroves patches occur in the villages of
Vatuolailai, Tagaqe, Vatukarasa, and Korotogo. Reports from Thaman et al.,
(2002) indicated the presence of mangroves previously in the villages of
Namatakula, Navola, Komave and Malevu. To the west of Sigatoka town, the mangrove patches are more extensive and occur adjacent to the villages of
Yadua, Naevuevu, and Rukurukulevu.
43 The natural features of the Coral Coast have been a major tourism attraction. Tourism contributes 35-40% of GDP annually, making it the largest export earner. The Coral Coast is the third highest tourism destination in Fiji with an occupancy level of 68% per night following Nadi (72.5%) and the Mamanuca groups (70%) (Smith & Zographou, 2006). The high level of occupancy reflects the increased number of large hotels and smaller tourism operators spreading out along the coast. This consequently has led to the increased the population along the Coral Coast because of employment opportunities offered by the industry. This rapid economic and population growth adversely affects the environment. The Coral Coast therefore is faced with an array of environmental issues.
2.2 Environmental Issues
One major issue the Coral Coast is facing is the deterioration of the coral reef ecosystem. A range of anthropogenic activities such as over fishing, destructive fishing methods, sedimentation, eutrophication, live rock harvesting and pollution has contributed to this situation. This has been a major concern from the communities along the Coral Coast (Thaman et al., 2002). Natural occurrences has also made significant contribution towards agitating even further the decline of reef health, by means of outbreaks of the coral eating Crown of
Thorns starfish (Acanthaster planci), coral bleaching events and storm damages.
2.2.1 Live Rock Harvesting
Live rock harvesting for the aquarium trade occur along the three villages of the studied area; Vatukarasa, Malevu and Namada. Live rock is removed from
44 the reef as blocks 15-35 cm in diameter usually by iron bars. Collectors gather from areas predetermined by the customary chief. Impacts of coral harvesting includes breakage of non-target species, potential destruction of coral population, potential alteration of reef topography and conflicts with tourism operators.
2.2.2 Over Fishing
Decline of coral cover and fish abundance have been observed by the villages over the past years. The use of destructive fishing methods such as derris sp., dynamite fishing, undersized nets and over fishing has been the contributing factor to the decline in fish abundance (Thaman et al., 2002).
2.2.3 Deterioration of Coastal Water Quality
Deteriorating water quality is often blamed on the nearby hotels disposing of their solid waste and sewage waste into the ocean. However, the continued dependence of most of the villages on pit toilets and septic tanks out of which sewage waste may leach during heavy rains and the location of pig pens close to the ocean in many of the villages probably also contributes to sewage pollution in the coastal waters (Mosley and Aalbersberg, 2003; Pareti, 2006)
2.2.4 Logging
Logging is still carried out upriver of Komave, Navola and Votua villages and on the slopes above Tagaqe and Namada. The logging is primarily pine and is thought to be a major cause of soil erosion. A logging concession area,
Navutulevu, is active in the Coral Coast area. In 1997, 3,608 m3 of timber was harvested from the area.
45 2.2.5 Coastal Erosion
All villages except along the Coral Coast have indicated that coastal erosion was a major problem especially during storm surge (Thaman et al.,
2002). These storm surges damage existing seawalls, wash away houses, and cause extensive erosion of shoreline.
2.2.6 Pollution
The disposal of rubbish in the village and on the coast occurs in all villages. This is mainly plastics, tin cans, and other non-biodegradable solid waste. Due to there being no formal rubbish collection villagers often dispose of rubbish along the coastline assuming that the ocean will remove it. Siltation from small streams is also a problem in Namatakula, Komave, Navola, Tagaqe,
Vatukarasa and Korotogo especially during heavy rain. Votua and Votualailai communities also mentioned that the disposal of rubbish from nearby hotels and sewage disposal from the Votua Housing settlement via a small stream are a major cause of pollution in their coastal waters.
2.2.7 Overgrowth of Algae
The overgrowth of Algae, especially Sargassum species, is mentioned to be a problem in all villages (Thaman et al., 2002). The excessive growth of Algae smothers coral and is thought to be due to elevated nutrients in the waters, siltation and to higher ocean temperatures (Mosley & Aalbersberg, 2003).
2.2.8 Flooding
In two villages, Votualailai and Korotogo, the construction of the Queens
Highway has contributed to the floodings in the villages (Thaman, 2002). In
46 Korotogo the road is higher than the village and inappropriately constructed culverts lead to flooding in the village during heavy rain.
2.3 Problem Solving Efforts
The communities themselves have raised concerns on the deterioration of their resources. In response, government, NGOs, universities and various other organizations have come in to try and help them solve these problems. Projects such as waste management, Locally Managed Marine Areas (LMMA) and
Integrated Coastal Management (ICM) have been implemented and have been ongoing in the communities. UK based NGO, Coral Cay Conservation (CCC) has done baseline surveys all along the Coral Coast for the communities which provided some background data for this study. The procedures to solve problems used have been a “bottom up” approach. This involves communities identifying the problems and attaining help from organizations and stakeholders involved. The organizations along side the communities work together to find sound management practices.
47 CHAPTER 3: METHODS
3.1 Approach and Assumptions
A control-impact design was used to estimate the effect of live rock harvest. The study was initiated after harvesting, therefore the assumption is that there were no differences amongst reefs selected for study prior to the onset of live rock harvesting (i.e their natural abundances were similar). All reefs were selected to have similar geology/ecology.
A reef was regarded as a study unit. The magnitude of the effect was estimated by comparing reef fish abundance, substrate composition and depth profile between e among reefs that have been harvested and not harvested.
Reefs subjected to harvesting are considered “treatment” study units, reefs never harvested are not true controls but regarded as “reference” study units for comparison in this study. Statistical testing for the effects of live rock harvest was made using the null hypothesis or no difference (Ho). If there was no difference, the Ho was accepted. However, if a difference was detected the Ho was rejected and the alternate hypothesis (HA) of a significant difference was accepted.
3.2 Reefs Selected as Study Units Sites
The reefs were selected based on preliminary surveys by Movono (2004) and Coral Cay Conservation surveys during 2004. The GIS images that were produced by CCC were analysed for Coralline Algae, Sargassum, Hard Coral, and Rubble distribution and cover along the Coral Coast. Abundance of these substrate components were categorized based on colour intensity derived from the satellite images and were categorized as low, medium-low, medium,
48 medium-high and high coverage. This provided background information of the study sites which is explained in detail below. The previous and current surveys both showed that tabu areas, protected from fishing and areas open to fishing could have confounding effects on live rock harvest. If live rock harvest occurred in an area subsequently declared an MPA, fish protection had a confounding effect by inflating fish numbers without regard to live rock harvest. If live rock harvest occurred in areas open to fishing edible fish species, the effect of live rock harvest was confounded by decreasing numbers of edible fish with regard to live rock harvest. Therefore reefs selected as study units did not have tabu areas and were open to fishing. Also, families of non-edible fish, not targeted by fishing, were used as indicators. Four reefs were selected as reference study units (never harvested for live rock, NH); Votua, Silivaiyata, Vatuolalai and
Namatakula (Fig 3.0).
The GIS images and tools from Google Earth were used to calculate the areas of the eight reef units studied. These are included in the detailed descriptions of the eight reefs below.
3.1.1 Votua Reef
The beach comprises mostly of pebbles with an intertidal zone of abundant and substantial beach rock. The reef area is the largest compared to the three other non-harvested reefs, at 609km2. There is a lagoon with a shallow reef crest which is exposed at low tide. Currents are very strong during rising and ebbing tide especially on the reef flat adjacent to channels. A sewage flows into the stream by the village, which outflows into the beach front. There are piggeries
49 located near the stream. Apart from the villages, there is a government housing authority scheme community (Votua housing) which has 60 houses situated approximately 1 km inland. A baseline survey by CCC showed a low Coralline
Algae cover, medium brown Algae, low bed rock, low live Hard Coral, medium- high Rubble and a medium to high Sargassum sp. coverage.
There have been marine conservation measures here as Votua is one of the Fiji Locally Managed Marine Areas (FLMMA) sites. A Marine Protected Area
(MPA) is situated on the reef flat adjacent to the village. There is also an ecotourism dive shop (Mike’s Divers).
3.1.2 Silivaiyata Reef
This is a shallow reef with many gaps due to the patchy coral growth. The spaces therefore provides for water in the reef walls. The area studied on
Silivaiyata reef comprises about a third of the whole reef flat, an area of 0.114 km2 making the area the smallest of the four non-harvested reefs. The reef is adjacent to the channel; hence there are strong underwater currents during ebbing and flooding tides. The study site is located adjacent to an MPA. There is wastewater outfall nearby which flows onto the reef flats. A restaurant and a backpacker’s lodge is situated in front of the beach followed by the Silivaiyata
Reef. When study was undertaken, there was ongoing construction for the development of a resort adjacent to the lodge. A baseline survey by CCC showed naturally low Coralline Algae, medium brown Algae cover, low bed rock, low live Hard Coral cover, medium-high Rubble cover and a medium to high
Sargassum sp. coverage.
50 3.1.3 Vatuolalai Reef
This reef features a calcareous Sandy beach. The study area on this reef flat is approximately 0.290km2. The reef is shallow and gradually deepens.
Corals are in patchy distribution and the reef crest is not well developed. The site is adjacent to an MPA. There is an outfall outlet from the hotel and the village that flows into the beachfront. Adjacent to Vatuolalai Village is Naviti Resort which provides employment to the local community. CCC surveys show medium-low Coralline Algae, medium brown Algae, medium-low bedrock, medium-low live coral, medium Rubble cover and a low Sargassum sp. cover.
3.1.4 Namatakula Reef
The Namatakula Reef flat is an extensive one featuring a Sandy (granite) beach. The intertidal reef flat features a seagrass community. The area of the reef is approximately 0.312km2, the second largest of the four non-harvested reefs. The middle reef has much bed rock which leads to a shallow reef crest.
The shallow reef crest is exposed during low tide while the lagoon is submerged.
There is a channel in front of the village. The MPA is on the opposite side of the channel. A little stream from the village leads to the main beach. A resort is situated on either side of the village. To the west of the village is the
Beachhouse Resort and to the east the newly developed Mango Bay Resort.
CCC baseline surveys showed medium-low Coralline Algae cover, brown
Algae is medium-low, medium bed rock, medium-low live Hard Coral cover, medium Rubble and medium to low Sargassum sp. coverage.
51 The four reefs selected as treatment study units or reference reefs have a history of live rock harvest. The reefs are Vunisese Reef (Namada), Oria Reef,
Navoto Reef and Natarawau reef (Malevu).
3.1.5 Namada Reef
The reef flat is extensive; however the collection study site is on the right hand side of the reef adjacent to a bay. The area studied is 0.145km2 which is a third of the entire reef. The reef flat is shallow and exposed during low tide.
There are rocks, Rubble and pebbles on the beach. Currents are strong due to the passage/bay.
There is an eight-year history of live rock harvesting on the reef flat which is currently on-going. Live rock is usually harvested daily for 3 weeks, stops for a week and then rotates after a month.
A river flows into the bay. Logging also occurs inland up the river. There is much evidence of extensive coastal erosion. The nearby village and resort is
Namada Village and Tambua Sand Resort. There is a 3 year MPA site adjacent to the harvesting sites and marine parks. Marine parks are part of an ecotourism project involving the villagers as tour guides for tourist snorkeling activities.
CCC surveys show that there was a medium-low Coralline Algae, medium-high brown Algae cover, medium bedrock cover, medium-low Hard
Coral cover, medium Rubble cover, and medium to high Sargassum sp. cover.
3.1.6 Oria Reef
This shallow fringing reef is populated by Diadema urchins, Echinometra.
There is a white calcareous beach featuring beach rocks. The reef area is
52 approximately 0.347km2 .The current is very strong owing to the adjacent Sovi
Bay. The reef has been extensively harvested for the past 8 years. Harvesting occurs all over the reef flat. There was evidence of Derris sp. fish poisoning.
Apart from the village, the nearby Indian community comes here for fishing. The reef is right in front of a resort development site. CCC survey showed low
Coralline Algae cover, high brown Algae cover, low bed rock cover, low live coral cover, medium Rubble cover, medium-high and a high Sargassum sp. cover.
3.1.7 Navoto Reef
This is a large reef flat exposed at low tide, featuring a pebbly beach.
The reef covers an area of 0.625km2, the largest of the eight reefs studied. The reef crest is shallow and wide. Currents are strong when wind is strong. There has been extensive harvesting occurring for the past 7-8 years all over the reef.
The reef is adjacent to the Sovi Bay therefore exposed to run off. There is a small backpacker’s facility behind the reef.
CCC survey showed a low Coralline Algae cover, medium-high brown
Algae cover, medium-low bedrock cover, low live coral cover, medium-high
Rubble cover and a medium-high Sargassum sp. cover.
3.1.8 Malevu Reef
The reef features a pebbly granitic beach, covering an area of about
0.607km2. This reef system has a relatively deep lagoon. The left side was surveyed immediately adjacent to the village. This side of the reef was relatively patchy and contained gaps. As part of a coral restoration project, a Japanese
53 NGO called OISCA have placed coral racks in the lagoon. The reefs have a live rock harvesting history of five years since starting in 1992. This stopped and resumed for a year in 2003 and then stopped.
The reef is at the front of Malevu village and adjacent to this is Tubakula beach resort. Hotels and resorts share the same reef including Outrigger Resort and Vaka Viti Resort. The reefs are exposed to an outfall from the village and hotels.
CCC surveys showed that there is medium-low Coralline Algae, medium- low brown Algae cover, medium bedrock cover, low Hard Coral cover, medium
Rubble cover, low Sargassum sp. cover.
54 Figure 3: Coral Coast maps study area with the eight reefs near the seven villages. The harvested reefs (H) are by Malevu, Vatukarasa and Namada Villages. The non-harvested reefs are by Vatuolalai, Votua and Namatakula villages
55 3.3 Differences amongst reefs
The closer the proximity of the reefs is to each other, the more similar they would be. The harvested reefs are closer to each other in terms of their general reef structure. However the reference reefs could not be situated adjacent to the harvested sites due to the history of intensive harvesting along the Coral Coast on the west of Sigatoka up to the first reference reef which was Vatuolalai (where harvesting had been opposed by the communities) (Fig 3.0). The control sites vary in that some feature a more calcareous Sandy beach, whilst, others have a more terrigenious beach. They differ in the sizes of the lagoon and the area of the reefs flat, t-test on size of the areas between the four harvested and non- harvested reef do not show any statistical difference (t-test: p=0.43, t- critical=2.44). However, the areas are not different from each other in terms of geological history as they are all part of the same fringing reef system. A major difference of Malevu Reef from the rest of the reefs is the coral restoration project. This coral restoration is a program set up by a Japanese NGO called
OISCA. This involves coral racks being placed in the lagoon to restore the coral population.
3.4 Indicators Selected for Live Rock Harvest Effects
The indicators chosen for the study were based on preliminary sampling by Movono (2004), MAC (2004) and CCC in 2004 indicating that invertebrates were too patchy and low in density to have statistical reliability. The indicators chosen were non-edible or low priority edible fish families: Chaetodonidae
(Butterflyfish), Blennidae (Blennies), Gobiidae (Gobies), Pomacanthidae
56 (Angelfish), Pinguipedidae (Sandperches), Pomacentridae (Damsel fishes) and
Synodontidae (Lizard fishes).
The Reef Check life-form category was used for indicators of substrate composition (Appendix ii). The only modification made to suit indicator for live rock was that Coralline Algae was prioritized over Macro Algae. This means that if there was Macro Algae on the surface but Coralline Algae beneath, would be recorded as Coralline Algae. This modification was made after consultation with harvesters who indicated that live rock was harvested based on Coralline Algae cover. Collectable live rock was consolidated material, with more than 50-70% coralline cover, beneath Sargassum sp. In this study, the collectable live rock was categorized under Coralline Algae. If Macro Algae was on Rubble or Sand- this would be categorized as Macro Algae. The categories used were: Coralline
Algae, Hard Coral, Soft coral, Algae (macro Algae, turf Algae and Algae assemblage), Sponges, Abiotic (Sand, Rubble and rocks) and Others
(zooanthids inverts etc).
Working with the assumption that live rock harvest will change depth, depth profiles were taken of each reef to determine if such an effect could be detected.
3.5 Methods Used for Sampling
Three sites were selected at each of the eight reefs. At each site, two 100 m transects, end to end and 10 m apart were laid perpendicular to the beach to cover the reef crest and back reef area. Each 100 m transect was divided into
57 four 20 m segments with 5m in between the segments. In total, this equates to twenty four 20 m segments in each of the eight reefs.
Fig 3.1 test 1
100m
20m
Fig 3.1.1 Shows the four 20m segments in one hundred meter transects with 5m intervals in between the segments
58 A belt transect technique was used to count fish in all twenty-four 20 m segments at each reef. The belt-transect technique involved a snorkeler swimming through a 20 x 5 m segment and counting individual fish of the seven indicator families. There were three Reef Check trained personnel that provided assistance in the surveying of fish. The substrate composition was categorized using a modified Reef Check point intercept method, where the substrate type was recorded at meter intervals along each segment (Appendix 1).
Depth was measured to the nearest 1 cm using a graduated rod every meter along the segments at every site on the reefs. The start and stop times of each segment were taken to standardize depth profile to chart datum. GPS points were also taken at the beginning and end of each transect (Appendix iii).
Each of the eight reefs was visited once. The surveys were conducted at a time when good weather and tide were suitable and personnel were available.
Initially four sites were chosen when the first two reefs were surveyed (Oria and
Namatakula); this was later reduced to three sites when surveying other 6 reefs.
It was found that 3 sites represented a better coverage for all the reefs and there were two zones distinct which were prevalent amongst all the reefs. For analysis purposes only the three sites which were common to all the eight reefs were used.
59 The four sites on Oria Reef were surveyed during 1st -6th of May 2005.
The four sites on Namatakula Reef were surveyed during 20th -22nd of June
2005. The three sites each on the Namada, Navoto and Malevu Reefs were surveyed on the 30th November-1st December, 2005 respectively. The remaining three control reefs (Votua, Vatuolalai and Silivaiyata Reef) were surveyed from the 21st -23rd of March, 2006.
3.6 Data Analysis
A 20m segment was the unit of analysis for the fish and substrate data.
3.6.1 Fish data Analysis
The frequency of each fish family on each reef was tallied and tabulated.
Fish individuals from the 24 segments on each eight reefs were counted and categorized into respective groups from 0-9, 10-19 and so forth. For comparison purposes, since 2 of the eight reefs (Oria and Namatakula reefs) had 32 segments compared to the 24 from the other reefs, the mean number of fish counts was used. A frequency table was synthesized for each family in the eight reefs and graphed . A frequency graph of each of the seven fish family was constructed using SPSS version 10.5
The fish data were analyzed using a chi-squared test., Chi-square is calculated by finding the difference between each observed and theoretical frequency for each possible outcome, squaring them, dividing each by the theoretical frequency, and taking the sum of the results:
Where:
60 Oi = an observed frequency;
Ei = an expected (theoretical) frequency, asserted by the Ho.
Pearson's chi-square is used to assess two types of comparison: tests of goodness of fit and tests of independence (Mendenhal, 1991). A test of goodness of fit establishes whether or not an observed frequency distribution differs from a theoretical distribution. A test of independence assesses whether paired observations on two variables, expressed in a contingency table, are independent of each other. Chi-square test was used to analyze the difference in abundance of each of the seven fish familiies between the four harvested reefs and four non-harvested reefs using SPSS Version 10.5. A significant chi- squared value indicates a significant difference in the fish abundance between harvesting and non-harvested reefs. A chi-squared test was also used to compare the abundance of each fish families within the four harvested reefs. A significant chi-squared value indicates a significant difference amongst the four harvesting reefs. The same statistical analysis was done for the four non- harvested reefs.
The next step was to apply two analytical procedures to the data on the distributions of the seven key families first an index of association (the Bray
Curtis dissimilarity measure) (Legendre and Legendre,1998) was used to establish the degree of similarity of the species compositions (families present and abundances of each) at the eight different reefs. Each reef was compared to each of the remaining seven and given a rating, ranging from 0.0 for complete similarity (all attributes with identical values) to 1.0 for complete dissimilarity (no
61 attributes in common) (Fig. 4.1.8 and Table 4.1.8)(Legendre and
Legendre,1998).
3.6.2 Substrate data analysis
All substrate data from each of the 24 segments on the eight studied reefs were entered into EXCEL, Windows XP and grouped using the pivot table. The percentage substrate in each of the eight reefs was calculated and graphed
(Figure 4.2). The substrate composition was analyzed using a chi-squared test on the total composition of the four harvested and four non-harvested reefs. A significant chi-squared value indicates a significant difference in the substrate composition between the harvested and non-harvested reefs. Chi-squared test was also used to compare differences within the four harvested reefs. A significant chi-squared value indicates a significant difference within in the four reef types. The same analysis was conducted within the four non-harvested reefs.
The Z-test is a statistical test used in inference which determines if the difference between a sample mean and the population mean is large enough to be statistically significant. In order for the Z-test to be reliable, certain conditions must be met. The most important is that since the Z-test uses the population mean and population standard deviation, these must be known. The sample must be a simple random sample of the population. If the sample came from a different sampling method, a different formula must be used. It must also be known that the population varies normally (i.e., the sampling distribution of the probabilities of possible values fits a standard normal curve). If it is not known
62 that the population varies normally, it suffices to have a sufficiently large sample, generally agreed to be (Table 5).