Chapter 1. General Introduction. Abstract

Transcription

1 General Abstract An investigation has been carried out in various islands of Lakshadweep Archipelago to assess the status of coral reefs and distribution pattern of butterflyfishes during 2008 to In this introductory part of the thesis description of the study area, objectives of study and organisation of the thesis is provided along with a brief introduction to the subject. A brief description of the methodology followed is also provided.

2 Chapter 1 General 1.1 Coral reefs have a highly restricted distribution in the world, concentrated mostly in tropical and subtropical seas, are the only ecosystem that is strongly defined by geological component (Kleypas et al., 2001). Darwin (1842) was certainly preoccupied with just how reefs formed and postulated that the subsidence of volcanic island can result in the evolution of fringing reefs to barrier reefs and atolls (Maragos et al., 1996). Reefs are certainly recognized as complex ecosystems having both biological and geological features. The growth potential of reefs and carbonate platforms depends largely up on the growth of the frame-building organism (Dullo, 2005). Reef is built from coral species but not all corals produce reef (Barnes and Hughes, 1999; Veron, 2000). Hermatypic zooxanthellae symbiotic scleractinian corals build the reef (Barnes and Hughes, 1999). Coral growth depends on various exotic and endogenic factors (Buddemmeier and Kinzie, 1976). The vastness of coral reef ecosystems may be seen in their numerous ecological, aesthetic, economic and cultural functions. Atoll and barrier reef islanders recognize that healthy reefs are essential for the support, creation, and repair of the coral islands upon which they live. Coral reefs also protect coasts from shoreline erosion, and serve as a living pantry for the subsistence harvest and consumption of many reef organisms and benefiting millions of people around the world (Mongbay, 2011). The cycle of reef accretion and erosion maintains beaches and provides habitat for sea grasses and mangroves. Coral reefs are important recreational resources for most of the world's people having the privilege of living near them (Crosby et al., 1995; Crosby and Maragos, 1995). South Asia, Pacific, Australia, Indian Ocean, Atlantic and Middle East are the major coral reef regions of world. The major coral reefs in South Asia occur in the Maldives, Chagos, Lakshadweep and the Andaman and Nicobar Investigation on Coral Reef of Lakshadweep Archipelago with Special Reference to Butterflyfishes 1

3 Islands (Rajasuriya et al., 2004). The reefs of Indian Ocean consist of atolls, fringing reefs, barrier reefs, patch reefs, elevated banks and submerged banks. Coral reefs in India occur principally in the Lakshadweep, Andaman and Nicobar Islands, Gulf of Kutch, Gulf of Mannar and Palk Bay. The Gulf of Mannar and Palk Bay islands are a series of shallow fringing uninhabited islands. The reef fauna is closely allied to Sri Lankan coral reefs (Arthur, 2000; Rajasuriya et al., 2004). Coral reef community composed of a variety of organisms and the reef structure provide habitat for one of the highest diverse ecosystems in the world. Coral reef ecosystems are characterized by high species diversity, productivity and complex interrelationships of reef biota. Fishes are the one of the most important functional components of the reef systems. As most reef fish are dependent on the substrate for both food and shelter, it can be expected that the nature of the reef influences fish species richness, composition and diversity. The effect of reef architecture on biodiversity has been extensively studied, especially the relationship between reef rugosity and reef fish assemblage (Talbot, 1965; Risk, 1972; Luckhurst and Luckhurst, 1978; Gladfelter et al., 1983, Pratchett et al., 2006, 2011; Wilson et al., 2009; Kerry and Bellwood et al., 2012). Butterflyfishes (Family: Chaetodontidae) are among the most common and conspicuous fishes in coral reef communities (Burgess, 1978). The colourful butterflyfishes living in shallow tropical seas are site specific and mostly diurnal feeders which feeds on coral polyps and other invertebrates (Findley and Findley, 2001) More than 125 species of butterflyfishes are distributed worldwide in tropical and temperate waters (Kuiter, 2002). The highest diversity of butterflyfishes is recorded from the Indo-Pacific but the diversity decreases as one move away from this region (Zekeria et al., 2013). Many studies have showed that a positive relationship between butterflyfish assemblage and live coral cover or coral species richness (Sano et al., 1984, 1987; Bell and Galzin, 1984; Bouchon-Navaro, 1986; Bouchon-Navaro and Bouchon, 1989; Roberts et al., 1992; Chabanet et al., 1995, 1997; Pratchett et al., 2004, 2008a, 2011). However, a number of other studies have disagreed, at least to some extent Investigation on Coral Reef of Lakshadweep Archipelago with Special Reference to Butterflyfishes 2

4 (Bell et al., 1985; Roberts and Ormond, 1987). Butterflyfish are used as biological indicator for a simple and effective way of monitoring coral reefs for long term changes. It cannot tell us the specific causes of the impact but allows us to act in the early stages (Tim, 2006). Spatially explicit conservation and management plans for the butterflyfishes have to be developed only after delineating the links between species distribution and habitat characteristics, at a variety of different spatial scales (Dalleau et al., 2010). Though, butterflyfishes are reported to be a functional member of the reef system and studies have been carried out on various aspects from different reefs of the world, an in depth investigation on this group of fishes is yet to be initiated in the Lakshadweep archipelago. Detailed study with appropriate methodology has not been carried out in Lakshadweep, further research on the description on the percentage cover and distribution of the coral species and the benthic substrate composition status of the Lakshadweep reefs are rather scanty. Similarly the ecology, population characteristic, distribution, feeding habits, and social systems of Butterflyfishes, the most common and conspicuous fishes in coral reef communities, is meager. Therefore, a study has been carried out to with following objectives to throw light to some aspects of reef systems and ecology, population characteristics, distribution, feeding habits, and social systems of Butterflyfishes 1.2 Objectives of the Study 1. To establish trends in coral abundance and status of coral health in the reefs of Lakshadweep Archipelago 2. To document the percentage cover and distribution of the coral species of the atolls of Lakshadweep Archipelago 3. To evaluate the relationship between Butterflyfish (Family: Chaetodontidae) assemblage and live coral cover 4. Investigate the distribution patterns and community structure of Butterflyfishes in the Coral Reef of Lakshadweep Archipelago and Investigation on Coral Reef of Lakshadweep Archipelago with Special Reference to Butterflyfishes 3

5 5. To understand the underlying basis of dietary preference in coral feeding Butterflyfishes 1.3 Study Area Lakshadweep is an archipelago distributed in the Arabian Sea (8 and 12 30' N, 71 and 74 E) off the South West coast of India. It is one among the smallest Union Territory of India with 20,000 km 2 territorial water, and 4,00,000 km 2 of exclusive economic zone. Lakshadweep constitutes the only atoll formation in India and figures the northern most segment of the Chagos Maldive Laccadive oceanic ridge (Fig. 1.1). Atolls are special coral reef formations that are highly productive and diverse in the otherwise nutrientpoor, oligotrophic oceans. A typical Lakshadweep island has a north south orientation and a shallow lagoon on the west with an average depth of 6 m that is connected to the open sea through entrance channels. The sea around Lakshadweep and reef lagoons are of great ecological significances, highly productive at primary and secondary levels, as they accommodate the highly diverse fauna and flora associated with the coral reef and influence the high sea resource to great extent. These islands still remain to be one of the least studied groups of coral islands in the Indian Ocean for its reef resources, ecology, biology, and environmental status. The reef system of Lakshadweep is biologically very significant in view of the isolation from major continental coastline as well as for their rich diversity in marine life (Pillai, 1986; Suresh, 1999; Arthur, 2002). It consists of 15 atolls having a total area of 32 km 2 and five submerged sand banks in which 11 are inhabited islands with a growing population of 67,000. Archipelago also includes 16 uninhabited islands and 3 submerged reef consisting of a total lagoon area of 4200 km 2 (Fig. 1.2.). Investigation on Coral Reef of Lakshadweep Archipelago with Special Reference to Butterflyfishes 4

6 Chapter 1 Figure 1.1. Map Chagos Maldive Laccadive oceanic ridge (Lamont ( Daberty Geological Observatory, New York, 10964) Figure 1.2. Map of Lakshadweep showing various islands. (Source: Source: Maps of the world). Investigation on Coral Reef of Lakshadweep Archipelago with Special Reference to Butterflyfishes 5

7 Due to its location and due to governmental restrictions it has been rather isolated from the rest of the world. This isolation has lead to greater protection from direct human impacts, but has also resulted in very few scientific studies being carried out in these waters. Although most of the studies that exist are focused on fish, in comparison to other coral reefs of the Indian Ocean (for example Maldives, Seychelles, or the Chagos Archipelago), the fish of Lakshadweep have still received far less attention, and Lakshadweep's fish fauna is yet to be fully discovered. A thorough knowledge on ecology of the reef systems which includes the dynamics of environmental and diversity of reef biota is a necessary prerequisite for planning, judicious utilization of the resources and effective management leading to conservation of this particular ecosystem. It would also provide information to minimize the research gap in several lacunae incorporating to reef biology, ecology and oceanography of this area. Geologically Lakshadweep group of atolls located on the prominent N-S Lakshadweep ridge and the alignment appears to be a continuation of the Aravalli strike of Rajasthan. Based on this, many geologists have speculated that the islands are a buried continuation of the Aravalli mountain chain and that the Deccan Traps have been faulted down in the sea along the west coast of India. A great thickness of traps and associated sediments occur to the West. Based on seismic study, Ermenko and Datta (1968), inferred that the Indian shield (continental crust) extends as far as to the Lakshadweep. The transition zone separating the continental and oceanic crust occurs to the west of the Lakshadweep. Further, using seismic refraction measurements Francis and Shor (1966) postulated that 1.5 km to 2 km thick volcanic rocks lie below the sea floor on the Lakshdweep ridge. Initial reports of the deep sea drilling project; indicate possible connection with western and through this to the eastern shelf of India. Other evidence indicated that the ridge was faulted down in Lower Eocene when the Lakshadweep sea was formed and the ridge was separated from the peninsular India. The Lakshadweep ridge runs for a distance of 2000 km from Lakshadweep Islands at 14 N latitude to Investigation on Coral Reef of Lakshadweep Archipelago with Special Reference to Butterflyfishes 6

8 Chagos Islands at 6 N latitude. The ridge rises from the deep sea, from depth of m in Lakshadweep sea and 1000 m in Arabian sea. The eastern flank of the ridge appears to be steeper than the western one. The ridge is composed of oceanic basalt, capped by recent coral reefs in the form of atolls and coral banks. These atolls and coral banks rise steeply from sea bottom with depth varying from 1500 m to 3000 m and their average surface elevation is 5-10 m above mean sea level. These atoll reefs show various stages of development of the islands. The reefs at Cheriyapanniyam, Perumalpar, Bangaram and Suheli represent the earliest stage while Kalpeni, Kavaratti, Agatti and Kadmat are in intermediate stage. Chetlat and Kiltan are in an advanced or mature stage of development. Lagoons of Kiltan and Chetlat islands are growing at a very fast rate; and are likely to be filled up with sediments in a decade or so, while Andrott Island is one of the matured Island formations in this archipelago (Wagle and Pravin, 1999). Climate is predominantly influenced by ocean atmosphere interactions like tropical cyclones, hurricanes, storm surges, inundation, and erosion. Currents around Lakshadweep are part of the global ocean conveyor belt (Fig. 1.3). As a unique feature, the direction of currents changes with the seasons around Lakshadweep (Fig.1.4), monsoon drift of the Arabian Sea and Indian Ocean strongly effected up on the biological productivity of both open seas and coral reefs lagoons. The climatic conditions of the islands are not differing from Kerala even though the southwest monsoon and northeast monsoons both contribute their shares of rainfall to these islands The average annual rainfall is around 1200 mm, and it is more pronounced in islands between June and September. Atmospheric temperature is of uniform pattern with slight increase from South to North. The atmospheric temperature starts rising in February and reaches its peak in May. The average temperature of the islands ranged between C and 32 C. The temperature decreases one or two degrees with the onset of the southwest monsoon during June and again shows a slight rise in October and it remains Investigation on Coral Reef of Lakshadweep Archipelago with Special Reference to Butterflyfishes 7

9 almost uniform up to January. Throughout the year the air is humid, with relative humidity varying from to 83.08%. Figure 1.3 Great Ocean Conveyor Belt - Dominant Currents in Lakshadweep. (Source: Figure 1.4. Monsoon Drift in the wind pattern in the Arabian Sea (Source: UNEP-WCMC, World Fish Centre) Investigation on Coral Reef of Lakshadweep Archipelago with Special Reference to Butterflyfishes 8

10 Fauna of Lakshadweep The living resources in and around the Lakshadweep Islands hold great potential for exploitation, the marine biological and fisheries research in the Lakshadweep Sea and lagoons dates back to the last quarter of the 19th century, started by the British naturalists A. Alcock in Marine biological event in this region was that of the Cambridge University expedition led by Prof. J. Stanley Gardiner. Results of this expedition were reported in the volumes of "The Fauna and Geography of the Maldive and Laccadive Archipelagoes" (Gardiner, 1903, 1906). Earlier information on the marine fauna of Lakshadweep was mostly based on the various articles published in these two volumes. The expedition has concentrated mainly on taxonomy and distribution of corals Pillai (1971a, 1971b, 1972, 1986, 1987). Information on the crustacean resources of Lakshadweep is limited to only a few reports on crabs, lobsters, prawns, and stomatopods (Lanchester, 1903; Sankarankutty, 1961; Shanbhogue, 1986). Species composition, distribution and taxonomic description of polychaete fauna in the seagrass beds of the Minicoy lagoon, Lakshadweep, India were studied and 27 species of polychaetes belonging to 14 genera were identified (Susan et al., 2011). Early studies on the brachyuran crabs and lobsters of this area are those of Borradaile, published in the two volumes of "Fauna and Geography of the Maldive and Laccadive Archipelagoes". Records of echinoderms taxonomy and distribution from Lakshadweep are that of Bell (1902); Kochler and Vaney (1908). More detailed work on the echinoderms of Lakshadweep was carried out by James (1969). Distribution pattern and community structure of Sea cucumber in different biogeographic region was recently studied by Idreesbabu and Sureshkumar (2010). Early studies on the Molluscan fauna are those of Eliot (1906), Hoyle (1906), Smith (1906) and Burton (1940). Recently many studies have been initiated in Lakshadweep on corals (Pillai 1971 to 1989; Wafer, 1986; Suresh, 1991; Srivastava and Koya, 1998; Arthur, 2004). However, their status is restricted to taxonomic descriptions and qualitative assessments. Quantitative description on the percentage cover of the coral species distributed in atolls of Lakshadweep is essential for Investigation on Coral Reef of Lakshadweep Archipelago with Special Reference to Butterflyfishes 9

11 the assessments of reef health and future trends. Ichthyofauna of Lakshadweep attained special interest from very long since. Some of the early accounts on this are that of Alcock (1890). Balan (1958) documented 80 species of fishes belonging to 65 genera. Jones (1960, 1969); Jones and Kumaran (1967, 1971) and Jones et al., (1969, 1970) also contributed to the documentation of Ichthyofauna of Lakshadweep. Even though there are many studies dealing with taxonomy of marine fishes of India (Day, 1958; Munroe, 1955) the fishes of Lakshadweep Islands have received little attention. The first concerted attempt for the documentation of fishes from these islands was done by Jones and Kumaran (1980). In their publication, Fishes of the Laccadive Archipelago, which is an indispensable work on taxonomy of fishes from the region which documented 603 species of fishes. The most recent and complete work on ornamental fishes of Lakshadweep was carried out by Murty (2002), with a report of 18 species of Chaetodontids from various islands of Lakshadweep. Vijay and Pillai (2002) documented habitat distribution and species diversity of coral reef fishes in the reef slope of Kavaratti atoll through the visual census method and recorded 4 species of the family Chaetodontidae. Review of literatures revealed that 22 species of 4 genera of butterflyfishes of the family Chaetodontidae occurred in Lakshadweep waters and also stated that no detailed study has been carried out on the occurrence and abundance of various species of the family Chaetodontidae. Earlier attempts for marine living resource documentation on the coral reef of Lakshadweep could not undertake appropriate methodology to perform a detailed study on occurrence and distribution and community structure of butterflyfishes which closely coincide with the limits of coral growth. DeSilva (1984) pointed out that detailed survey methods prescribed for coral, the documentation of biodiversity of coral reefs involve extensive diving and skilled personnel support. The absence of SCUBA facilities, fishes where surveyed with the mask and snorkel apparatus which is inefficient to observe all species (Vijay and Pillai, 2002). Investigation on Coral Reef of Lakshadweep Archipelago with Special Reference to Butterflyfishes 10

12 1.4 Methodology For the data collection on benthic substrate composition and butterflyfishes, underwater survey methods using SCUBA and snorkelling was adopted. Line intercept transects (LIT) in water depths from 1 m to 21 m were used to obtain data on benthic community profile and coral percentage cover (Loya, 1972; English et al., 1994). The benthic substrate compositions of all the twelve inhabited islands were worked out. Transect were laid horizontally along the substratum and data collected along each transect by visual census supported by photography and video documentation (Fig. 1.5). The data collected were further verified and validated by crosss checking the field data with the photographic and video document. Among the substrate category, the live corals were identified to genus/ species level and the position of every change in substrate type was recorded. Genus and species level data on the corals was collected using the Indo Pacific Coral Finder robust underwater plastic book (Kelley, 2009). Belt transects (Brock, 1954) and timed swims techniques were adopted to record the occurrence and abundance of species of the family Chaetodontidae. For the present study, atolls were demarcated into three zones viz. sandy intermediate lagoon (SIL), inner reef slope (IRS) and outer reef slope (ORS) and survey was conducted in these three zones of four inhabited islands. Timed swims could cover large areas and were particularly useful to sample species that are unevenly distributed or occurred in low densities (English et al., 1994). The fishes were identified up to species level and their abundance was recorded on underwater data sheet (Zekeria et al., 2003). Total percentage cover and benthic substrate composition status were calculated from primary data collected. Calculation of the percentage of benthic substrate composition type was based on the contribution of each substratum to the total length of projection. Microsoft Excel for Windows was used for the descriptive statistical analysis. Primer 6 software (Clarke and Warwick, 2001) was used for diversity analysis. Non metric multidimensional scaling was also adopted to configure the points in Investigation on Coral Reef of Lakshadweep Archipelago with Special Reference to Butterflyfishes 11

13 Euclidean space between the coral reef area based on the mixed picture of the benthic status and percentage of coral species coverage in different reefs of various atolls. Hierarchical cluster was developed to find the similarity in distribution of butterflyfishes in different geomorphologic zones of the atolls. Primer 6 software was used for the analysis of community structure (Clarke and Warwick, 2001). Figure 1.5. Methodology adopted for the survey. A. 20 m LIT used for coral survey, B. Bet transacts adapted for fish count, C. Permanent submerged marker used for continues monitoring the same site, D. Snorkelling used in the shallow depth ranging 1-5m, E. Photographic and video documentation during the survey and F. SCUBA used in the deeper water ranging 5-21 m for the study Investigation on Coral Reef of Lakshadweep Archipelago with Special Reference to Butterflyfishes 12

14 1.5 Coastal Habitat and Morphology The proper management and suitable conservation strategies are in need for the sustainability of reefs in general and the different geomorphologic and biogeographic regions of the atolls in particular. Mangroves and Coral reef are the two main biogeographic regions of these atolls. Mangroves are restricted to Minicoy and Kalpeni atolls of Lakshadweep. The water is often turbid with silty bottoms in mangroves, which provide shelter for many species with their root system and forms a nursing ground for many fishes. Three species of mangroves are reported from this archipelago (Susan, 2005). Coral reef ecosystems have very high species diversity, productivity and complex interrelationships between reef organisms. As most reef fish are dependent on the substrate for both food and shelter, it can be expected that the physico-chemical and geomorphologic nature of the reef influences fish species assemblage and diversity (McClanahan et al., 2014). Lagoons, channels, inner reef slope, reef flat, reef front, outer reef slope and dropoffs/walls are the main geomorphologic zones of an atoll (Burkov, 1982) (Fig. 1.6) Lagoon, depths may vary from less than a meter to 12 m depending on the extend of circulation of water there may be many patch reefs or just large stands of Acropora corals growth, indicating the healthy lagoon. Seagrass beds and mud flats, inside the Lagoons are supporting many fish varieties for their food and shelter. Atolls like Bitra, Minicoy and Suheli have very deep lagoons. Recent observations showed that depth of the lagoon is getting reduced by means of sand accumulation (Wagle and Pravin, 1999). The study also depicted that channels connecting lagoons with the open water are important to provide fresh and colder water for the lagoons. Accordingly, currents provide ideal conditions for plankton-feeding animals. Depending on wave action and temperatures the surface may be just a complex maze of interconnecting channels, tide pools and sand patches. Coral growth is usually poor; at the reef front, where the reef takes the full force of wave action (Lalli and Parsons, 1995; Veron, 2000). Investigation on Coral Reef of Lakshadweep Archipelago with Special Reference to Butterflyfishes 13

15 Figure 1.6. Geomorphological zones of the atoll. A. Island, B. Lagoon, C. Inner reef slope, D. Channels, E. Reef front, F. Outer Reef flat, G. Outer reef slope, H. Drop off Investigation on Coral Reef of Lakshadweep Archipelago with Special Reference to Butterflyfishes 14

16 The study also incorporated that live coral assemblages are restricted at reef front and usually there is a dominance of rubbles and sand ( Barnes, 1987). Visibility in reef front might be because of the pressure of sediments raised by the tide and waves. In the outer reef slope the edge of the reef is fairly steep and slopes down to the deeper water. Since the water is generally clear, corals grow to depths of 50 m depending on light availability (Veron, 2000). There might be interesting caves, overhangs or gullies in the reef slopes which are nearly vertical resembling drop-offs/walls. Sand and sediment are trapped and accumulated in terraces or shelves. There are vertical chutes with sand along the outer reef slopes having horizondal and vertical currents along the wall and along the chute respectively. 1.6 Organisation of the Thesis Result of the study and survey conducted for a period of four years (September, 2008 to August 2012) are embodied in the thesis entitled "Investigation on Coral Reef of Lakshadweep Archipelago with special reference to Butterflyfishes ". The thesis is presented in 7 chapters to convey the research findings in a legible way. Chapter 1 deals with the general introduction and organisation of the thesis summarizing, brief introduction of Lakshadweep Archipelago, Geological features of Lakshadweep Atolls, Climate, Oceanography, Coastal habitat and morphology of the Atolls. A brief introduction to the reef fishes, fishes of the Lakshadweep with reference to butterflyfishes is also included in the chapter. This chapter also provides an outlook to the necessary pre-requisite measures for planning future utilization of the resources, for effective management and conservation of this ecosystem. Chapter 2 provides a summary of the current state of knowledge of the coral reef and reef formations in India. An updated review of literature relevant to the ecology and population status of butterflyfishes, its global distribution and the effect of coral cover on local abundance, feeding habits, territorial behavior and social systems is included in the chapter 2. The concept of butterflyfishes as biological indicator is also discussed with a brief review. Investigation on Coral Reef of Lakshadweep Archipelago with Special Reference to Butterflyfishes 15

17 Chapter 3 deals with Coral surveys using line intercept transects (LIT) in water depths from 1 m to 21 m to obtain the reef profile and coral percentage cover to explain a benthic substrate composition status of 12 atolls of Lakshadweep to document the present status of diversity and occurrence of coral in reef of archipelago. Chapter 4 deals with systematic accounting of family Chaetodontidae with new records of five butterflyfishes collected from the Lakshadweep Archipelago. This chapter discusses the morphometric features used in the systematic section and a key developed for the identification of different species of the Chaetodontids reported from Lakshadweep is also included. Detailed description of the new records of five butterflyfishes from the study area with notes on occurrence of four additional species is also included. Need for extensive scientific survey of fish biodiversity in Lakshadweep archipelago has been highlighted and the importance of Lakshadweep archipelago is emphasized. Chapter 5 deals with distribution pattern and community structure of butterflyfishes in the coral reefs of Lakshadweep. A random belt transects fish count survey in different geomorphologic zone of the atolls were conducted to understand the distribution pattern and community structure of site attached butterflyfishes of these archipelago. Chapter 6 emphasis the fish survey using the Belt transects and timed swims techniques as described by Brock, 1954 to record the population and abundance of the butterflyfishes. Another aspect attempted was timed swims could cover large areas and were particularly useful to sample species that were unevenly distributed or occurred in low densities to get an idea about the population and abundance in selected atolls of Lakshadweep. Chapter 7 deals with the food and feeding of two obligate coral-feeding butterflyfishes distributed along the coral reef of Lakshadweep archipelago. This provides the underlying basis of dietary preference in coral feeding butterflyfishes. This chapter also explains the level of partiality among different coral genera and also within the species of same genera in response to different local condition. The result infers the establishment of the Investigation on Coral Reef of Lakshadweep Archipelago with Special Reference to Butterflyfishes 16

18 individualistic response of butterflyfishes to the local distribution of the coral species to reduce the competition between the species to coexist. The seventh chapter is followed by the Summary and Conclusions of the investigation. List of relevant literature consulted and cited are provided in the reference section. Investigation on Coral Reef of Lakshadweep Archipelago with Special Reference to Butterflyfishes 17