Cikobia Island. Marine Ecological Survey Report, May Macuata, Vanua Levu.

Transcription

1 Cikobia Island Marine Ecological Survey Report, May 2010 community on Cikobia Island, off North This report is dedicated to the shared vision of the Macuata, Vanua Levu.

2 TABLE OF CONTENTS Page # Report at a Glance 2 I. Introduction: Cikobia Island 3 II. Survey methodology 4 Manta tow series 4 Coral reef survey 4 Seagrass watch 5 III. Survey results 6 Manta tows 6 Coral reef health 7 Seagrass health 9 IV. Discussion 10 V. Guiding principles for managing our tabu 11 VI. VII. References Appendices- Cikobia fish list Beche- de- mer species of Fiji in export market List of Figures: Figure 1. Seagrass ID sheets. Chart 1. Mean percent cover of benthic for deep and shallow transects. Chart 2. Percent coral life- form distribution along 50m point transects. Chart 3. Average count of fish abundance per functional group for deep and shallow transects. Chart 4. Average count of sasalu invertebrates along deep and shallow transects. Figure 2. Satellite imagery of Cikobia with zones highlighted for protective management. List of Tables: Table 1. Summary of the manta tow results 1

3 LIST OF ABBREVIATIONS CC CDC GEF ID SGP Climate Change Cikobia Development Committee Global Environment Facility Identification Small Grants Programme REPORT AT A GLANCE This survey activity and report was commissioned by Cikobia Development Committee under its GEF SGP funded community- based project. The marine ecological surveys of Cikobia s surrounding reefs profiled that of a hardy marine environment exposed to stormy and oceanic influences. Remote Cikobia is situated in the path of cyclone tracks through Fiji, with a history marred by sea tragedy, lyricized in song and stories remembered by the islanders. Transect and manta tow surveys profiled an underwater world mainly composed of hard rock with a smattering growth of robust coral forms like encrusting, massive Porites, Pocillopora, Acropora coral species and hanging cliffs where seabird colonies rest, wall of volcanic rock which disappear straight into the deep blue water. Larger pelagic fish were a common sight during the surveys. Schools of some key threatened yet commercially known species like the bumphead parrotfish, other parrotfish, unicorn fish, trevally and the humphead wrasse have been observed to be prevalent. Such ecological baseline information contributes to the knowledge base of resources on Cikobia that inform, ongoing community- led integrative processes to establish protection and management strategies for this remote island economy. 2

4 I. INTRODUCTION- CIKOBIA ISLAND Cikobia is an exposed wind- whipped island located South, East of Fiji. The island is roughly about 18.9 sq km (7.3 sq mi) and predominately limestone with remnant volcanic outcrops. It retains remnant upland and littoral native forest but much of the land has been replaced by grassland due to burning and agriculture, introduced pine and coconut plantations. Cikobia also retains one of the earliest documented lapita archaeological sites in Fiji, yet very little research on other aspects of the island. Anecdotes from the island community, indicated that Cikobia still retain sizeable colonies of coconut crabs which are threatened or extinct in many parts of Fiji and the Pacific; and local populations of sea turtles and sea birds. The community present on the island is relatively small with less than 200 people living spread across the four villages. Majority of Cikobians have relocated over the last forty years to the mainland due to lack of services and facilities on the island. These non- resident islanders despite their relocation still retain user rights and most, access natural resources on the island periodically. The community is predominately subsistence, dependent on agriculture and fisheries, with minor commercial activities such as the sale of copra, beche- der- mer and pandanus. Due to their isolation, the islanders are rarely able to access information regarding the importance of environmental awareness and disaster preparedness. Community members retuning to the island have reported an increase in unsustainable land use practices, such uncontrolled burning and clear felling native trees without efforts for replanting. This has resulted in gradual decline in food security, crop productivity and manufacture of traditional crafts linked to the natural resources on the island. Extreme weather conditions of hot dry periods or lack of rain causes water shortage for there are no surface freshwater sources. More intense and frequent windy, stormy conditions exacerbate the shoreline erosion as evident in the droopy coconut heads, thus proving to be an increasing problem for the villagers who live less than 500 metres from the high tide mark. Cyclones and storms regularly affect the island as it often lies within their path as it traverses the Fiji group. Cyclone Daman that passed through Fiji in November 2008, devastated the island communities homes, service facilities and gardens to a worth of over half a million Fiji dollars (Northern Division Report, 2008). With projections and strong links confirmed by climate experts on increasing cyclonic events in future, there is a growing need for communities such as those on Cikobia to be aware of global climatic change and initiate building resilience to such adverse impacts. This report is a step taken to guide Cikobia s integrated planning of community development, protection of biodiversity and safeguard of livelihoods. Women waiting for the boat. 3

5 II. SURVEY METHODOLOGY Manta tows were done during the first three days to provide a quick assessment of the reef areas surrounding Cikobia, prior to the survey dives at pre- selected sites. Procedures followed standard manta tow protocol detailed in Survey Manual for Tropical Marine Resources (English et al., 1997). The trained community team observed and recorded according to three categories i.e hard coral, soft coral or dead coral and cover estimations recorded during the manta tows. Coral cover estimations were converted into a score of five- point scale, 1: 0-10% cover, 2: 11-30% cover, 3: 31-50% cover, 4: 51-75% cover, 5: % cover and averaged for each tow area (eg. MT OT1). Start and end position of each tow were recorded using a gecko GPS unit. Sites selection was done on the basis of: Reef areas adjacent to the cliffs towards the western corner of the island where the bird colonies and at least a site representative of the leeward and windward part of Cikobia; Local knowledge of good fishing spots known for fish foraging, spawning aggregations; Inner shallow reef areas adjacent to villages, nesting beaches and seagrass growth. Coral reef surveys were conducted using SCUBA diving gear by a team of 4 divers during the week. Methods were adapted from the Reef Check methodology protocol for which five types of data were accounted during each transect survey dive as listed below: A site description was completed that had data on anecdotal, observational historical on the location of the reef region/island; 1 st diver placed a 50m line transect on the reef to count fish of commercial value and targeted by the local fishing community. 2 nd diver assigned to count fish, swam slowly along the transect tape and stopped every 5m for about 3 minutes allowing target fish to come out of hiding before moving to the next 5m stop; 1 st diver assigned to lay the tape returns to start of tape to count invertebrates found within a 5m wide belt along the 50m long transects. Invertebrate taxa that was usually collected as food or curios for trade was counted; Any signs of coral bleaching or disease (discoloration of live coral or white coral skeleton covered Survey equipment list: Manta tow board + 17m (10mm) towing rope Harness rope to attach to rear of boat Refractometer & Stopwatch 3 x slates to attach recording sheet 3x pencil+string+clipboards to attach onto slate board 4x 50m measure tapes Underwater printed sheets of Site description/ fish/ invertebrate/ benthic substrate Reference books- fish+seashells+marine algae First aid kit + bottles of water Dive equipment: Compressor to fill the 10 dive tanks hired 6x (BCD+weight belt+regulator+wetsuit) 6x pair booties +mask +snorkel +pair fins Emergency Oxygen Kit with algae); 3 rd diver recorded substratum types and benthic community of the reef along the same 50m transect which was point sampled at 0.5m intervals. Standard Reef Check protocol specifies that the categories recorded under each 50cm point are: hard coral, soft coral, recently killed coral, dead coral, fleshy seaweed, sponge, rock, rubble, sand, silt / clay and other. Additional categories recorded hard corals to life form level (along with target species), soft corals and categories of algal cover (mixed assemblage, coralline, Halimeda, macro and turf ) into non- coral benthos, abiotic categories included the non- living part of the reef surveyed. Finally, the substratum surveyors recorded coral damage from anchors, dynamite, or other factors and trash from fishing nets or 4

6 other. Divers rated the damage caused by each factor using a 0-3 scale (0 = none, 1 = low, 2 = medium, 3 = high). All data were transferred to specially- designed recording forms (Appendices). Seagrass watch surveys characterize the habitat by visual estimates of above- ground biomass percentage cover using a 0.25m 2 quadrat. Techniques were adopted from Seagrass- Watch: Manual for Mapping & Monitoring Seagrass Resources by Community Volunteers. (2nd Edition. Department of Primary Industries, Queensland, Northern Fisheries Centre. April 2003). Field equipment: Seagrass watch Kit includes 4x0.25m 2 quadrat Seagrass ID guide Data sheets (3 per transectx3 transects/site) 50m measure tape 30cm ruler to measure seagrass blade length Magnetic compass Within a seagrass area, at least 3x50m transects were laid out parallel to each other, at least 25m apart and perpendicular to shore. For every, 5m mark along the 50m tape, a quadrat was placed for sampling according to the following steps: Figure 1. Seagrass ID sheets Step 1- describe the sediment composition by feeling the texture of sediment from the top centimeter of the substrate. Note the grain size in order of dominance e.g. sand, fine sand, mud. Step 2- estimate seagrass percent cover within the quadrat- use the percent cover photo standards as a guide. Step 3- estimate seagrass species composition by identifying each species of seagrass within the quadrat and determine the percent contribution of each species to the cover (must total 100%). Use seagrass species identification keys provided. Step 4- measure canopy height, ignoring the tallest 20% of leaves. A 30cm ruler was used to measure from the sediment to the leaf tip of at least 3-5 shoots. Step 5-6 Estimate algae percent cover in the quadrat. Algae are seaweeds that may cover or overlie the seagrass blades. Step 6- Estimate epiphyte percent cover. Epiphytes are algae attached to seagrass blades and often give the blade a furry appearance. Step 7- Describe other features and ID/count of macrofauna. Note and count any other features of interest eg. number of shellfish, sea cucumbers, sea urchins, evidence of turtle feeding. In this field trip, samples of seagrass and photographs were not taken at each quadrat/transect site. At completion of monitoring, datasheets were checked and filled in completely, i.e. ensure that observers name, date and site/quadrat details are clearly recorded on the datasheet. 5

7 III. MARINE SURVEY RESULTS Manta tows. A total of 80x2minute tow series were conducted with the team spending 3 hours of observation in the water conducting preliminary survey of the surrounding reefs. Manta tow (2 min. series) Number of tows Date of tow th May th May th May Table 1. Summary of the manta tow results for Cikobia during May surveys. Manta tow site A. Old jetty site, Saqani- Nalele village, Vuninuku Live coral cover % Dead coral cover % Soft coral cover % Visibility, m Other observations m Cliff escarpment, large bommies Porites sp. schools of red- tail snapper, trevally, rabbitfish B. Tuvulevu m 3 turtles, varivoce, kalia, groupers C. sand cay adjacent village Turtle, varivoce, parrotfish 6

8 Coral reef health were profiled based on a total of 13 transect surveys at the fringing reef zone, outer barrier reef slope sites, reef flat zone and passage (refer to map for locations). The cliff escarpments and Cikobia island s oceanic topography didn t present ideal reef habitats for clear designation of transect placements. Transect depths ranged only between 2-12metre depths where coral life form is present. Horizontal visibility was rated at 10-14m and water clarity to at least 15m deep. Survey results indicated highest coral cover to be found at marine area adjacent to Tuvulevu coastline. The mean percent cover of benthic on the reef for shallow transects indicated the non- coral such as the algal, soft coral components and abiotic to be rubble, rock and sand categories to be most prevalent. The results of mean benthic cover along the 50m deep transects showed similar trends of non- coral and abiotic categories recorded. Also noted in the live coral components, Acropora coral types were recorded and found in the deeper transects at about 10-14m depth. Predominant coral life- forms in deeper transects were submassive, massive and branching. The coral component on shallower transects were mainly that of robust life- forms of either low branching, encrusting or massive growth to be prevalent. The reef surrounds is typical of a system exposed to oceanic influences and the hardy conditions therein as evident in the physical profile of the reef. 7

9 Observed fish data was summarized into deep and shallow reef transects across the patch and barrief reef slopes both close to shore. On average, fish abundance was noted to be higher at deeper reef transects with noted larger sized commercially important fish species. Chart 3 illustrated the pattern of fish family groups. For deeper transects, fish species with diets feeding on plant material (herbivores) such as parrotfish, surgeon- fishes and scavengers/ generalists like snappers, emperors and sweetlips, were most common along the fish transect count. In shallower transects, common fish groups were herbivores and other fish categorized for moray eels, wrasses and sharks/turtle. Humphead wrasses and aggregations of bumphead parrotfishes were sighted during transect surveys around the island. Generally, the fish population observed during the survey period were noticeably large sized and in schooling numbers. Common reef creatures found on the reef flats were documented to indicate reef health and fishing pressure mainly, as shown in Chart 4. The distribution of invertebrates were relatively diverse on the deeper transects with at least 7 types of invertebrate types compared to the shallow transects with 5 invertebrate types observed. The commonly found invertebrates along the shallow transects were triton, cowries and cone shells typically absent in mainland reefs. There was also the concerning presence of crown of thorns, a killer of coral reefs found present in the deep and shallow transects, although most common in the latter. The cleaner banded coral shrimp was a dominant feature on both transects. Sea cucumbers were the invertebrates found common with tarasea as it was locally known to be abundant (34% coverage) along the deeper transect. 8

10 Seagrass health: Data yet to be analysed and tabulated! Table 2. Description of seagrass cover and fauna distribution at the surveyed shore sites of Cikobia during May Seagrass site Mean canopy height, cm Mean seagrass cover, % Mean count, organisms Figure 2. Satellite imagery of Cikobia with zones highlighted in dash boxes for protective management 9

11 IV. DISCUSSION The crux of observing the fish, the type of reef surface and the kind of organisms found living on the reef were to determine how the reefs looked like and functioned, as baseline to local resource knowledge and ongoing efforts to sanction reef areas for protection. Remote Cikobia proves less challenging to place protective measures due to limited pressure by resource exploitation for market demand from nearest Labasa town on Vanua Levu. Based on field experiences, there were at least two key elements considered towards the island s fisheries. This included a case study for the commercial harvesting of bech- de- mer and recognizing the value of local seagrasses in order to safeguard the marine web of life and ecosystem resilience by connecting the schools of larger fish aggregating in the surrounding deep to protecting the integrity of coastal habitats. Case study: How healthy is the beche- de- mer fishery? Sea cucumbers as earthworms of our lagoons help vacuum sediment off corals from blockage where polyps (small animals that live in the coral skeleton) need the sunlight for food to build our coral reefs. Sea cucumbers feed off detritus found on the reef bottom by engulfing sediment, grounding it as the sand bits pass through its gut and excreted, leaving a trail of finer sand than before. The sea cucumbers feeding process contributes to the breakdown of larger sediment types and aeration of reef sediment, crucial for all bottom dwelling organisms which feed and live within the reef substrate on the floor of the lagoon. The issuance of license to collect beche- de- mer for its commercial sale is primarily intended to regulate collection. However, the current state of the sea cucumber fishery in Naviti is unknown. It is important to keep check on the fishery in considering the elements of safety in diving to collect beche- de- mer plus the conservation value of this important species. Six key ecosystem health indicators frame management concerns of this fishery as outlined below: Take some, leave some for breeding How to fish for sea cucumber How many sea cucumbers Types of sea cucumbers Sizes of sea cucumbers Profit to the fishers This can be the first step to consider island- level management of this fishery in conjunction to the role of Fish wardens sanctioned by the Department of Fisheries. Why survey seagrass? The plant s structure and height of the seagrass canopy, the extent of the meadow is influenced by a number of ecological factors such as water motion caused by currents and waves. Usually the leaves are wider and weaker in areas with slow water motion, and narrower and more flexible where water movement is higher. Where present, seagrasses form the basis of many ecologically important marine 10

12 habitats supporting far reaching biotic, living communities. It has been suggested that 400 square meters of seagrass (10metres long and 40 metres wide) can support 2000 tonnes of fish a year. Fiji s coastal fisheries productivity depends greatly on seagrass habitats. For example, juvenile emperor fish (sabutu, cabutu, kabatia, kabatiko) live in the shallow inshore areas where seagrass and mangroves before they move to deeper waters as adults (Richards et al. 1994). Seagrasses are a known resource for green turtles in the central south Pacific region. The seagrass areas in Fiji may well be providing foraging areas where turtle search for food by over half of the adult green turtles in the central South Pacific (McKenzie et al. 2007). This could be a result of lower availability of turtle food east of Fiji, where most islands are small and steep with limited areas suitable for seagrass growth. There has been not much careful attention given to seagrasses however, contributions from field observations with community groups to map local seagrass areas as part of own resource planning, should be applauded. Such initiatives of keeping watch over local seagrass areas also contributes to global insight on how seagrasses could be a major local influence on seawater that could alleviate the problems of ocean acidification. It has been discovered that varieties of seagrass could help reduce the acidity of water surrounding coral reefs. This is a potential solution to endangered coral reefs vital to providing natural fishing and sea defenses for most of us living on small islands in the South Pacific. Due to increased carbon dioxide in the atmosphere, the survival of these calcium carbonate forming corals raises the acidity of the oceans. Scientists made the analogy about the risks of ocean acidification rotting our reefs, the same way that fruit and fizzy drinks can erode tooth enamel. Past studies indicate that there are varieties of seagrass which can photosynthesis (complex process by plants converting carbon dioxide, water and inorganic salts into carbohydrates) quickly and efficiently that they actually turn the surrounding water more alkaline. ( wales- south- west- wales ) V. GUIDING PRINCIPLES: MANAGING OUR TABU The guiding principles of tabu management evolve on the concept 'to limit your catch, not catching your limit' and promoting the assessment, monitoring and protection of seagrass areas though its local eyes global wise volunteers network. Seagrass beds and shores adjacent to the villages is recommended for protection with set up measures to maintain the beach vegetation and mitigate beach erosion, household dumping, zoning areas for boat anchors. Levels of Protection seasonal, permanent, species relevant eg. Prominent species of humphead wrasse, bumphead parrotfish, coconut crab Seagrass beds adjacent to the village at Vuninuku Mangroves along the creek at Vuninuku Patch reef especially located at the pass before entering the anchorage in front of Vuninuku. High populous bird areas along the cliffs, leeward of the island. Coconut crab populous areas- demarcate areas of no collection. 11

13 VI. REFERENCES 1. Colin, P.L., and Arneston, C Tropical Pacific Invertebrates. A field guide to the Marine Invertebrates Occurring on Tropical Pacific Coral Reefs, Seagrass Beds and Mangroves. A publication of the Coral Reef Research Foundation. 2. Friedman, K., Purcell, J., Bell, J., and Hair, C Sea cucumber fisheries: a manager s toolbox. ACIAR Monograph No. 135, 32pp. 3. Gosliner, T., Behrens, D.W., and Williams, G.C Coral reef animals of the Indo- Pacific. A Sea Challengers Publication. 4. Seagrass- Watch: Manual for Mapping & Monitoring Seagrass Resources by Community Volunteers. 2nd Edition. Department of Primary Industries, Queensland, Northern Fisheries Centre. April English et al., Survey Manual for Tropical Marine Resources. Australian Institute of Marine Science. 6. Northern Division Report, Commissioner Northern Office, Labasa. 7. UND GEF SGP, Project Document. Improving Land Management and adaptive management approaches to disaster and climate change impacts on Cikobia Island. List of websites visited: wales- south- west- wales VII. APPENDICES FISH LIST_CIKOBIA ISLAND Local name in Cikobia Qio Aboa Qio moce Qio saqa Qio bulubulu Vai Vai damu Vai domonivonu Vai varoro Vai bulubulu Dabea Dabea Yaso Loulou Common name (ref.page Fish dictionary) Sharks Zebra shark (1) Short tail nurse shark (1) Oceanic whitetip shark (2) Reef blacktip shark (2) Rays Flapnose ray (4) Spotted eagle ray (4) Giant reef ray (4) Blue spotted stingray (4) Moray Giant moray (6) Salt and pepper moray (6) Freckled moray (6) Latin name Stegastoma fasciatum Ginglymostoma brevicaudatum Carcharhinus albimarginatus Carcharhinus melanopteno Rhinoptera javanica Aetobatus navinavi Taeniuva melanospilos Dasyatis kuhlii Gymnothorax javanicus Gymnothorax eurostus Gymnothorax fuscomaculatus 12

14 Dakudakulaci Te ute utugi Donu damu Donu loa Saqa drau Vo i Saqa Sasa Vilu Utouto Guru ni wai Tamo digo Tae a Sabutu Damu Mesa Sevaseva Orawa ni toga Yaumucu Matale Ululoa Do oni Do oni vudi Kacika Cucu Sirisiriwai Dranu a vonu Jivijivi Guru Tapauru Dumu Bobo Qoli Kanace Yawa Sa u Novu Covocovo Matapula Culani Merau Ji ilo Vulu i Sinusinu balotu Sinusinu Kasala Delabulewa Zebra moray (5) Barred moray (5) Spotted coral grouper (29) Marbled coral grouper (29) Shadow trevally (41) Indian treadfin (41) Giant trevally (42) Bluefin trevally (42) Silver pompano (42) Green jobfish (43) Black snapper (43) One spot snapper (44) Humpback snapper (45) Bigeye snapper (45) River snapper (45) Scribbled snapper (45) Harlequin sweetlips (48) Oriental sweetlips (49) Pearly spinecheek (50) Bigeye emperor (52) Sky emperor (53) Small tooth fish (53) Long face emperor (53) Yellowlip (53) Dash dot goatfish (54) Highfin rudderfish (55) Longfin spadefish (56) Butterfly fish (54) Angelfish (69) Emperor angelfish (72) Damsel fish (74) Blackspot tuskfish (91) Common fish caught: Indo Pacific tarpon (10) Milkfish (10) Reef needlefish (10) Indian frogfish (11) Doubletooth soldierfish (12) Red soldierfish (12) Blood sport squirrelfish (13) Long jawed squirrelfish (13) Peacock grouper (24) Flagtail grouper (25) Giant grouper (26) Black saddle grouper (27) Hexagon grouper (28) Potato grouper (26) Gymnomuraena zebra Echidna polyzona Plectropomus maculatus Plectropomus punctatus Carangoides dinema Alectis indicus Caranx ignobilis Caranx melampygus Trachinotus blochii Aprion vives Macolor niger Lutjanus monostigma Lutjanus gibbns Lutjanus lutjannus Lutjanus argentimaculatus Lutjanus vivultatus Plectochinchus chaetodonoides Plectorchinchus orientalis Scolopsis margaritifer Monotaxis grandoculis Lethrinus harak Lethrinus microdon Lethrinus olivacens Lethrinus xanthochilus Parupeneus barberinus Kyphosus cinerascens Platax teira Mullidae Centropyge Pomacanthus imperator Abudefduf Choerodon schoenleinii Megalops cyprinoides Chanos chanos Strongyluva incisa Antennarius nummifer Myripristis hexagon Myripistis murdjan Neoniphon sammara Sargocentron spinifrenm Cephalopholis argus Cephalopholis urodeta Epinephelus lanceolatus Epinephelus howlandi Epinephelus hexagonatus Epinephelus multinotatus 13

15 Batisai Donudromo Leopard coral grouper (29) Saddleback coral grouper (29) Plectropomus leoparclus Plectropomus laevis 14

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