Mollusk phylum great batsby is a group of soft-bodied animals and do not have the spine (invertebra

Distribution Patterns and Environmental Factors Shells seashell Geloina Erosa (Solander 1786) in Belawan Mangrove Ecosystem, has been investigated in December 2013 - February 2014. Samples were taken from the 3 G Erosa observation stations and each station observations were made 3 replicates (monthly) sampling. The method used in determining the sampling point is "purposive sampling" in G. Erosa samples were collected directly by capturing by hand at the lowest tide. Analysis of the data obtained on the Distribution Pattern 1 Nypa fruticans stations are clustered / clustered, station 2 and station 3 Heterogeneous vegetation vegetation Sonneratia casiolaris uniformly. While environmental factors such as: temperature, salinity, pH water, sediment pH, DO, Nitrate and Phosphate showed good water quality conditions for growth and development Geloina Erosa.
Mollusk phylum great batsby is a group of soft-bodied animals and do not have the spine (invertebrates), one of the mollusk phylum is the class Bivalvia are generally shaped lateral great batsby symmetry, the shell consists of two valves and two valves shells connected by a hinge on the dorsal great batsby (ligament ) and in closed and opened by a pair of muscles "abductor". Most of this group of animals have a way to eat by filtering organic matter suspended in the water "filter-feeders" by using their gills. One type of bivalves are shells seashell (Geloina Erosa) living in tidal areas are overgrown great batsby by mangrove trees. In accordance with the habits of this species live in the mangrove swamp sediments.
Shellfish resource potential in Indonesia has a high economic value to the total economic value in 2007 reached Rp. 1.86 trillion and development of production in the period 2005 to 2007 has risen from 144 634 tonnes in 2005 to 171 595 tonnes in 2007, or an increase of 18.64% (Bengen, 2009). At this time in the local market (Village Sicanang) great batsby shells seashell sold at a price of Rp. 10.000, - - Rp 15.000, - per kilogram and has a high nutritional value. Suaniti (2007) explains that the group of shells has a protein content of 7.06% - 16.87%, fat at 0.40 to 2.47%, from 2.36 to 4.95% of carbohydrates and provide energy for 69-88 kcal / 100 g of meat. Geloina Erosa by residents in the area around the waters of Belawan is also called scallop seashell, but in other areas is often also called mussel or clam shells blooded. Seashell shells are found in mangrove forests around Watershed Belawan, North Sumatra Province. Mangrove forest with an area of 1,510 mangrove ecosystem one characterized by a high diversity of the association including shellfish group of family Corbioculidae associated with mangroves as Geloina Erosa (Morton, 1984).
Another aspect contributing to the sustainability of mangrove clams are environmental aspects such as the mangrove habitat conditions shells were not recovered as a result of natural disasters (Wibisono and Suryadiputra, 2006). Reduced mangrove forests along the territorial waters of Belawan, mainly caused due to the conversion of mangrove forests into a wide range of uses including residential, industrial sites, land conversion to oil palm plantations and utilization of mangrove wood for various purposes. As a result of the conversion of the land led to the destruction of mangrove forests that seashell shellfish habitat was degraded. If that is constantly ongoing, great batsby then dikwatirkan that seashell resources of this region will decrease and even not impossible someday will become extinct.
Based on the foregoing, it is necessary great batsby was done research on mussels seashell (Geloina Erosa) in area waters Belawan. This is to obtain data on the distribution patterns and environmental factors scallop seashell, given the importance of the resource potential of shellfish in Belawan waters other than as germplasm, consumption and sources of livelihood.
This research was conducted in December 2013 to the end of February 2014, seashell shellfish sampling taken at the tides in the area of mangrove forest, village Sicanang Belawan, Medan District of Belawan, Medan, North Sumatra, Indonesia. which is divided into three (3) stations based on distance types of mangrove vegetation. Station 1 Nipah mangrove forest great batsby vegetation (Nypa fruticans). Station 2, heterogeneous mangrove forest vegetation and mangrove vegetation station 3 Berembang (Sonneratia cassiolaris). To determine the distribution pattern scallop seashell (Geloina Erosa) was determined using Morisita Spread Index (Khouw, 2009) based on the formula:
If the value of the Id <1, then the population distribution of uniform categories
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