DISTRIBUTION, DENSITY AND IDENTIFICATION OF GIANT CLAMS IN COASTAL AREA OF NEGERI MORELLA, THE DISTRICT OF LEIHITU, CENTRAL MALUKU REGENCY, INDONESIA

ABSTRACT Giant clams are protected biota both nationally and internationally. The coastal area of Negeri Morella, the District of Leihitu, Central Maluku Regency, Maluku is one of the areas as the habitat of these giant clams. This study aims to identify the types of clams, conduct ecological studies covering density, diversity index of Tridacninae shells in Central Maluku, especially in Negeri Morella. Implementation of the clam population survey is conducted by using UVC (Underwater Visual Census). The results show that ofthe ten (10) samples in the observation station, 91 individuals of giant clams under the type of Tridacna squamosa and Tridacna crocea. The giant clams found in the coastal waters of Negeri Morella has a small size; in the depth of 1-5 m, 87 giant clams were found in various sizes with a length of 2-30 cm, and in the depth of 5-10 m, only four (4) giant clams with a length of 11-30 cm. The population density obtained was 45.5 individuals/ha, the value of Diversity Index (H’) was 0.69, the Uniformity Index (E) ranged from 0-1, and the Dominance Index (D) of 0.505.

Giant clams (Bivalvia, Cardiidae) are marine mollusks that live in coral reefs in the Indo-Pacific region. They come in two genera (Tridacna and Hippopus) with nine species, seven species of which are found in Indonesia. Geographically, these shells have limited distribution in the tropical region of Indo-Pacific, from the Red Sea to the Pacific Islands of Tuamotu (Yusuf et al., 2009). Tridacninae shells live in shallow waters, at a depth of 1 to 20 m . Tridacninae shells ecologically are biota which act as a natural bio filter, as they are able to filter ammonia and nitrate dissolved in seawater for the need of zooxanthellae of nitrogen for growth process . Tridacninae is known to have an important economic value because apart from being a source of food, the shells can be used as decoration materials and jewels. In addition, the shells are so much sought for jewelry and for the industry of terrazzo tiles, leading to the decreasing population of the species (Nontji, 2002).
Giant clams are protected biota both nationally and internationally. Internationally all types of clams included in the II CITES Appendix since 1985. Nationally, the giant clams are protected under Government Regulation Number 7 of 1999 that includes seven types of clams living in the waters of Indonesia. Their status are protected animals, where all forms of exploitative utilization (poaching and trade) are not permitted, excluding the results of cultivation, and after being given the status for game hunting (in accordance with Government Regulation Number 8 of 1999).
One of the coastal areas in Indonesia as the home of giant clams is the coastal area of Negeri Morella, the District of Leihitu, Central Maluku Regency, Maluku. The majority of the people here are farmers and fishermen. Along the coastal area are the home of giant clams, and the place of recreation and fish capture. The giant clams here are used as a food source traditionally. The local people call the giant clams as "biagaru". The use of the giant clams as a food source and jewelry has been done for generations. This also has caused the population of the giant clams to decrease.
Scientific information for types of Tridacninae in the region of Central Maluku, especially in the waters of Negeri Morella is not available; therefore the research aims to identify the types of clams through an ecological study which includes examination on the density and diversity index of Tridacninae.

MATERIALS AND METHODS
Population Survey Method. Clam population survey is conducted using UVC (Underwater Visual Census). There are two teams, each of two (2) people plus one (1) boat driver. These monitoring resources at least have an A1 diving license or equivalent and have good understanding of UVC method and types of clams. The boat drivers are fishermen of good knowledge about the locations potential for clams in the territorial waters of Negeri Morella and have the ability to use GPS (Global Positioning System). To estimate the population of giant clams, sampling is ten (10) observation stations representing the entire territory of the coastal area of Negeri Morella with a coastline of ± 10.7 km. Each station represents a one-kilometer coastline, with a hundred-meter transect at two depths. If the reef is steep in the stations, two repetitions with the same depth are done.
The procedure for giant clam survey is as follows: 1. Determine the location and number of monitoring stations starting from the shoreline as the 0 point. Mount the peg as a marker and record the coordinates; 2. Expand the rope starting from the point 0, 100 m parallel to the shoreline to a depth of 3-15 m; 3. Write down all the individuals and types of clams found under the transect line and as far as 5 m of the observation area for each observer so that the total range of both observers is 10 m. The total area of observation is 10 m x 100 m or 1,000 m 2 ; 4. Record all types of clam found in the observation area. Measure the shell width using stainless ruler. All data is recorded into the observation sheet (slate or waterproof paper) for further processing; 5. Record other information such as coastal vegetation, the slope of the reef, conditions (sand and rubble), and if possible record the former bomb and coral bleaching due to rising sea surface temperatures or predation by Achantasterplancii. The value ranges between This shows that the distribution of biota dominates the population evenness of the biota is. This in which a type of biota does not Dominance Index. Using i. Diversity index refers to a structure of organism communities about the type and number of species. The more of the waters is. Diversity index calculation (Magurran, 2004)  Evenness expresses how evenly the individuals in different species . Index is obtained maximum value as follows: Where: E = evenness index; H'max= In s; S = the number of biota.
between 0 to 1. The smaller the value of E, the less distribution of each type is different and there is a possibility population. In contrast, the bigger the value of E, This shows that the number of individual of each not dominate the population. Using the dominance index by Simpson  minance index; Ni= the number of individual number type number. is classified as follows:  During observation, 91 as many as 23 giant clams, followed in station 3 and 4, as many as  giant clams were found. The highest number followed by station 6, as many as 22 clams, and as 1 clam.  Station (  Amount the statement that the clamshell Morella utilize these clams as . The giant clams Tridacna hard rock while still a juvenile piece of mantle tissue that comes serves as a permanent adhesive. weak acid that can soften or begins to form a hole. After a soften the lime around the shell close the shell will erode the (Yonge, 1936; survey was in a range of comparison with other types of Population based of the observations consisted of a variety smallest size with a length of 2 or equal to 10 cm, as many size of clams is presented in the  clamshell is able to grow to the size of 40 cm length. as a food source and they take the clams during Tridacna crocea begin to cling on the substrate surface form with a size of 4-20 mm  comes out of the openings in the byssus at adhesive. The mantle tissue at the base of the shell dissolve limestone (CaCO3) that over time hole is formed, the giant clams continue to issue shell . The mechanical movement the already fragile coral part that the hole Jones, 1976). The size of Tridacna crocea 2-10 cm. Tridacna crocea has the slowest of clams. Shell size increases only 1-2 mm per the Number and Size of Clamps. The giant clams variety of lengths, the largest size with a length 2 cm. The average size mostly found was with as 70 individuals. Clam population based on the following figure.   (Nybakken, 2001).
Based on observations, how evenly the individuals in ). E value obtained highly even, or the number of RJOAS,9(69) Station (1)(2)(3)(4)(5)(6)(7)(8)(9)(10) Distribution of the Giant Clams' Length based on Depth. The small mostly found in shallow waters, while the large-sized clams were found in a depth of more    shows a value of five (5), population is not dominated by other organisms.
CONCLUSION of giant clams found in Negeri Morella, i.e. Tridacna population density of 45.5 individuals/Ha, diversity between 0-1, and dominance index (D) of 0.505.