The Abundance of Fish Species in Branched (branching) and Table (tabulate) Coral Habitat on Tanjung Beach, Muna Island, Southeast Sulawesi

ABSTRACT This research aimed to study the types and abundance of fish which was found in branched and table coral habitat. The quadrate transect method was used at the location of the habitat of branched and table corals. The observation was carried out for 3 days. It was conducted 3 times/day, in the morning, the afternoon, and the evening with ± 10 minutes of observation time for each observation. The method used was transect quadrat 5 m x 5 m with direct observation techniques by means of snorkeling. The types and numbers of individual fish were recorded using the visual census method. Snorkeling was done straightforwardly and looking around by following the contour of the reef. In branching coral habitat, 11 species of fish were found with a total of 66 individuals. On the other hand, on the tabulate reef habitat, there were 9 species of fish with a total of 50 individuals. Both habitats have different types of fish. In the branched coral habitats there were more individual than in the table reef habitats. Fish species found in branched coral habitat and table type fish habitat were different. In branched coral habitats were found more reef fish species than in table coral habitats. These results illustrated that the condition of the coral reefs at Tanjung Beach is still in good condition.


INTRODUCTION
The coral reef ecosystem is one of the marine ecosystems in habited by various type of marine life. The coral reef ecosystems are part of the marine ecosystem which is the place of life for various types of biota (Burke et al. 2012). Biota that lives on coral reefs is a community that consists of various tropical levels, where each component in this community is interdependent with each other and forming a complex ecosystem. One type of biota that lives on coral reefs is reef fish, with a high level of species diversity (Odum 1996). Coral reefs have ecological functions as a spawning ground, nursery Copyright: © 2021, J. Tropical Biodiversity Biotechnology (CC BY-SA 4.0) ground, and feeding for reef fish. Therefore the damage of coral reefs will affect the diversity and abundance of reef fish.
Corals have a variety of different growth forms. Various types of coral growth are affected by the intensity of sunlight, current waves, and sediment. The form of stony coral growth is divided into Acropora and non-Acropora corals. This type of branching coral is a type of Acropora coral (English et al. 1994). Branched coral is a type of coral with longer branches like tree branches. One type of branching coral is Acropora abrolhosensis. Table coral is a branching coral with a horizontal and flat direction like a table. This coral is supported by a rod that is centered or resting on one side which forms a flat angle. One type of table coral is Acropora latistella (Veron 2000).
The current condition of coral reef ecosystems in various territorial waters in Indonesia is in quite a rapid degradation. Southeast Sulawesi until 2016 having serious damage to coral reefs, around 80% of coral reefs are in a severely damaged condition (Department of Marine Affairs & Fisheries of Southeast Sulawesi Province 2016). The condition of coral reefs in Indonesia was around 6.39% in the very good condition level, 23.40% good, 35.06% damaged, and 35.15% in very critical conditions (Giyanto et al. 2017).
Tanjung Beach is one of the coastal areas in the Tongkuno district of Muna Regency, Southeast Sulawesi which is bordered by Buton Strait and has quite high fisheries resources, where around 80% of the people in this area work as fishermen. We identified there were four types of corals in Tanjung Beach. There was growth type with ramified (branching), solid growth type (massive), leaf type (foliose), and This is related to the interest of various species of fish in certain coral habitats that provide a variety of needs such as, places to find food, shelter, breeding places, and others. The presence of fish species against certain coral habitats may also be related to fluctuations in environmental conditions. Several studies reveal that the factors that influence the presence of fish (community structure and abundance of fish) in a reef community include a high and low percentage of coral cover (Bell & Galzin 1984). Besides the physical condition of the waters such as currents, brightness, and temperature were greatly affect the existence of reef fish (Nybakken & Bertness 2005).
The purpose of this study was to determine the types and abundance of fish found in branched coral habitat and table coral habitat.

Materials
Animals Fish species are found in branched coral habitats and reef fish species in tabulated reef habitats on Tanjung Beach, Muna Island Southeast Sulawesi.

Instruments
In this study, instruments used were boats or canoes as transportation during observation, GPS (Global Position System) to determine the coordinates of the research location, underwater writing instruments (water proof) to record observational data, underwater cameras to take documentation pictures, hand refractometer to measure sea water salinity, thermometer to measure sea water temperature, roller meter, and ping pong ball to measure current velocity, raffia rope to make square plots in coral reef communities, and coral fish identification book for identification. Data collection for reef fish was carried out using the quadrat transect method 5 m x 5 m. Observation of reef fish using a visual census method by snorkeling on the surface of the water straight ahead and following the contour of the reef (poking left and right) (English et al. 1994). The visual census was carried out for 3 days, in which 3 observations/day, namely morning, afternoon, and evening, with a length of observation of ± 10 minutes for each observation. Fish found during the visual census were documented, their species observed and the number of each individual was counted.

Methods
The collected data analyzed quantitatively, which was measured against the parameters of the reef fish community, namely the abundance and Similarity Index (IS) (Muller-Dumbois & Ellenberg 1974).

RESULTS AND DISCUSSION
The physical condition of the environment at Tanjung Beach Physical environmental condition is one of the indicators that greatly affect the life and survival of various biota. Based on the results of the survey, the condition of the coral at Tanjung beach was dominated by 2 types of coral, namely the type of branching coral (branching) and the type of table coral (tubulate). The existence of several types of reef fish in the community of table and branching corals is certainly influenced by water conditions or environmental parameters. Physical environment parameters for branching and tubulate coral types include water temperature, current velocity, and salinity. Environmental parameters measured in branching and tabulate coral habitats are presented in Table 1. The physical condition of the environment in branching coral habitat (branching) and table reef habitat (tabulate) relatively has similar measurements. The physical condition of these waters is still in the optimal range of marine life to survival, especially reef fish. The optimal temperature for the reef fish to grow is between 25-32 °C, this temperature range is generally found in tropical climates such as Indonesia (Whitten et al. 1984). The classified current speeds into several categories, very fast (>1 m/sec), fast (0.5-1 m/sec), moderate (0.25-0.5 m/sec), slow (0.1-0.2 m/sec) and very slow (<0.1 m/sec) (Laevastu & Hayes 1982). The currents can spread fish larvae as well as the food for reef fish such as plankton and currents scatter eggs and also larvae of various aquatic animals to reduce food competition with their mothers (Koesoebiono 1981).

Fish species found in branching and tabulate coral habitat
The highest presence and abundance were found in branching coral habitats compared to table coral habitats. 11 species of branching corals and 9 species of table corals were found. Fish species found in branching and tabulate coral habitat were presented in Table 2.  Based on Table 2, 18 species of reef fish were found and divided into 9 families. 11 species of branching corals and 9 species of table corals were found. There were 2 types of reef fish with the highest individual chopping on branching coral types, namely Amblyglyphidodon curacao 12 individual and Apogon chrysopomus 12 individual. On the other hand, there were 3 types of reef fish with the highest individual chopping on table coral, namely 11 individuals of Halichoeres chloropterus, 8 individuals of Amblyglyphidodon curacao, and 8 individuals of Thalassoma lunare.
The discovery of several species of fish with various individual numbers in the branched corals habitat can illustrate that there are a lot of micro habitats in branching corals. This allows these reef fish to use them together based on their needs such as spawning, foraging, and protection. Besides, the complex form of corals, branched, and the cavernous structure makes this type of coral attractive for fish to form their colony (Allen 1997;Thresher 1984).
Based on Table 2, there are 2 types of fish found in these 2 types of coral. These two species of fish are Amblyglyphidodon curacao and Siganus vulpinus. From this result observation Amblyglyphidodon curacao and Siganus vulpinus conjectured attracted with branching coral habitat and tabulate coral habitat. The species of reef fish would show a preference or suitability to the two habitats, it means the suitable habitat determines the abundance of these fish (Rondonuwu 2014).
The fish preference for certain habitats causes species diversity in coral reefs (Triana 2004). The complexity of habitat structure and environment of coral reefs plays an important role in the structure of the reef, therefore, fish communities enabling to share a habitat with many species and the existence and resilience of a fish species in one or more habitats depending on the habitat carrying capacity (Chabanet et al. 1997;Lee & Shin 2013).

The fish similarity index in branching and tabulate coral habitat
The similarity index analysis of reef fish species in branching and table coral habitats showed very different results. The results of the index calculation of fish species similarity between branched coral habitat (branching) and table reef (tabulate) are presented in Table 3.  (Odum 1996). This means, a low similarity index showing an indication that the types of fish occupied in branched coral habitat and table coral habitat are not the same. This means that the calculation of the similarity index aims to compare the composition and variations in the quantitative value of species at a location or habitat. This proves that the structure of the habitat complexity of branching and table corals in the research location is still in good condition (Ford et al. 2017).

CONCLUSION
In branching coral habitat founded 11 species of fish. Amblyglyphidodon curacao and Apogon chrysopomus are types of fish that have the highest individual numbers that were 12 species, while Lutjanus monostigma is a type of fish that has the lowest number of individual counts, namely 3. In the tabulate coral habitat, 9 species of fish were found. There are 3 types of fish with the highest individual number namely Halichoeres chloropterus 11 species, Amblyglyphidodon curacao 8 species, and Thalassoma lunare with 8 species.
Conversely, the lowest individual numbers were Chaetodon triangulum and Scarus schlegeli, each of them with 3 species, and Scarus oviceps with 2 species. The Similarity index of fish in branching coral habitat and tabulate coral habitat is 20.69%. These results illustrate that the condition of the coral reefs at Tanjung Beach is still in good condition.