Sea Urchin (Echinoidea) Distribution and Abundance in the Intertidal Zone of Bengkayang Regency

Sea urchins is the member of Echinoidea. This species can be found in tropical marine water to the poles. The study aimed to know the types, the abundance and spread of sea urchins in Bengkayang Regency. The research, used the transect method. Each station consisted of 3 transects with a length of 50 meters from the shore into the sea with the distance of 10 meters among the transects. This research obtained five species consisting of three species of the Diadema (genus) and two species of the Echinotrix (genus) i.e. Diadema antillarium, D. savignyi, D. setosum, Echinotrix calamaris and E. deadema. The density of sea urchins in Lemukutan Island ranges from 273 – 453 ind/Ha. The Density of sea urchins on Penata Kecil island ranges from 167 347 ind / Ha and on Penata Besar Island has a range from 307 387 ind/Ha. The highest diversity of sea urchins was found in Penata Kecil Island of (1.2355). The distribution of sea urchins in Lemukutan and Penata Besar Island was categorized into clumped and evenly distributed, while the distribution of sea urchin on Penata Kecil Island is included in the clustered and random categories. Distribution of sea urchins on the island is influenced by several factors such as sea water waves and food contained in the environment.

gency. The identification process of sea urchins was established in Zoology Laboratory Faculty of Mathematics and Natural Sciences University Tanjungpura Pontianak.

Description of Research Location
Lemukutan Island has an area of 12,520 ha, Penata Besar Island has an area of 4875 ha and Penata Kecil has an area of 975 ha. Lemukutan, Penata Besar and Penata Kecil Islands are located in Sungai Raya District. The northern part is adjacent to Tujuh belas Subdistrict of Singkawang City. The eastern part is adjacent to Samalantan district, while in the southern part is adjacent to Sungai Kunyit District and west with South part is adjacent to China Sea / Natuna.

Sample Identification
Sampling was done using the transect line. Each station consisted of three transects with a length of 50 m. Each transect had a distance of 10 meters with the other transects. Than samples were identified at the Zoological Laboratory of FMIPA UNTAN.

Environmental Parameter Measurement
Measurements of environmental parameters were carried out at each sampling station. Parameters measured include water and air temperature, brightness, depth, salinity and water pH.

RESULTS AND DISCUSSION
The sea urchins found in the intertidal waters of Penata Kecil, Penata Besar and Lemukutan Island were 5 species, comprising 3 species of the Diadema (genus) and 2 species of the Echi-

INTRODUCTION
West Kalimantan is a province that has the highest potential population of sea urchins, it can be discovered in Lemukutan, Penata Besar and Penata Kecil Island. Based on surveys that have been conducted of the islands, organisms the most widely found is sea urchins. Sea urchins, according to Hilda et al. (2012), are sea animals that 95% of them have thorns in the surface of their body. Sea urchin plays an important role in a food chain in the coast, especially in coral reef ecosystems. So, this animal can be found from tropical waters to poles.
Zakaria (2007) Lang & Schrerther (1976) stated that sea urchin had been used by the community as a source of food and played a role in the health sector. According to Angka & Suhartono (2000), sea urchin can also be used to lower blood pressure and improvebody metabolism. The population of sea urchins in the coastal ecosystems of Lemukutan, Penata Besar and Penata Kecil Island can be decreased by the excessive harvesting of sea urchins without conservation efforts and the damage to coral reef ecosystems due to human activities such as dock making and keramba.
The efforts to utilize sea urchins can be made with information about the distribution of sea urchins in water. Therefore, the study of the existence of sea urchin should be done especially regarding the distribution and abundance of sea urchin species in Lemukutan, Penata Besar and Penata Kecil Island of Bengkayang Districts.
This research is expected to provide information to the public and stakeholders about the existence of sea urchins in the area of intertidal waters on Lemukutan, Penata Besar and Penata Kecil Island of Bengkayang Regency.

Time and Place
The study was conducted from May -July, 2015 in intertidal zone of Lemukutan, Penata Besar and Penata Kecil Island of Bengkayang Re-notrix (genus). The type of sea urchin found was dominated by Diadema setosum (337 individuals), 80 individuals in Penata Kecil Island, 110 individuals on Penata Besar Island and 147 individuals on Lemukutan Island ( Table 2).
The density of sea urchins found in Penata Kecil Island ranging from 167 -347 ind / Ha. The highest total density was found in station 3 (around 347 ind / ha) and the lowest total density was found in station 2 (around 167 ind / ha). The highest frequencies of the sea urchin species in Penata Kecil Island were D. savignyi, D. setosum, E. calamaris and D. antillarium which have 100% of marking. More over, the lowest frequency occurred in E. deadema with 66.66% of marking (Table 3).
The density of sea urchins on Penata Besar Island has a range from 307 -387 ind/Ha. The highest density was at station 2 with around 387 ind/Ha, while the lowest total density was found at station 3 with around 307 ind/Ha. Species with the highest frequencies in Penata Besar Island were D. savignyi, D. setosum and E. calamaris with 100% and the lowest was D. antillarium 33.33% (Table 4).
The density of sea urchins found in Lemukutan Island has a range from 273 -453 ind/Ha. The highest total density at station 1 had a range around 453 ind/Ha, while the lowest total density at station 2 has a range around 273 ind/Ha. Species with the highest frequencies in Lemukutan Island were D. savignyi, D. setosum and E. cala-maris with 100% of mark (Table 3) (Table 6) The result of 'Morisita' index of types of sea urchins on Lemukutan, Penata Besar and Penata Kecil Island The spread of sea urchin in Penata Kecil Island has a tendency to split up ( Table 7). The sea urchins tend to clump or to have a greater score of Morisita index than 1 (IM> 1) which found in species of Diadema setosum, D savignyi, D antillarium, and Echinotrix diadema. There was one species      Vimono (2007), species of sea urchins such as A. lixula and E. mathaei are often found in specific habitats, such as in the crevices of coral reefs with a depth ranging from 1 -15 m.
with score IM=1 that tend to have a random namely E Calamaris. The spread of sea urchins on Penata Besar Island also tend to clump with score ((IM>1) (D setosum, D antillarium, E calamaris and E deadema) and only one species had a tendency to be harmonic with score (IM<1) which found in species of D. savignyi. The spread of sea urchins in Lemukutan Island also tend to clump (IM>1) and it can be found in D. Setosum and D. Savignyi, while the spread of harmonic (IM<1) can be found in E. calamaris and D. antillarium (Tabel 7) The Environment of Physical Condition at Research Locations Parameters of chemical physics measured on Penata Kecil, Penata Besar and Lemukutan Island were water temperatures (27° -32° C), air temperatures (29° -32° C), water salinity ranging from (33° -35°), water depth (54 -88.33 cm), Rahmasari et al. (2015) showed that environmental condition like temperature, salinity, pH, water velocity, and base substrated can effect on organisms abundance. The results showed that the density of sea urchins in each island is different. This is influenced by habitat conditions such as substrate and feed availability on each island. According to Kekenusa (1993) in Radjab (2000), differences in the value of the density of sea urchins can be attributed to the lack of food availability, as well as the ability to compete in habitat, both in the form of rocky areas and rocky waters The highest density of sea urchins was found in Lemukutan Island with a total density of 453 ind / Ha (Table 5). The lowest density of sea urchins was found in Penata Kecil Island with a total density of 167 ind / Ha (Table 3). Lemukutan Island has large coral reefs and there are many macroalgae in the island Andriyanto (2007) showed that there are 33 species of macroalga dominated by Phaeophyceae class from Dictyotaceae family, Padina gymnospora, Sargassum family, Sargassum paniculatum and Sargassum crassifolium, and Rhodophyceae class from Corallinaceae family, Amphiroa rigida According to Ratna (2002), main meals of sea urchins are Chlorophyta (green algae) and Phaeophyta (brown algae) The highest frequency of sea urchins from the three Islands was found in D. savignyi, D. setosum and E. calamaris species with 100%. D. savignyi has long thorns so that the spines can be deeper embedded in the bottom of the waters and protect it from sea waves. Therefore, the frequency of presence of D. savignyi is high D. setosum was found in sandy habitat types, coral reefs, to rocky areas. resulting in frequency of D. setosum on the Island to be relatively high Thamrin et al, (2011) stated that D setosum was the sea urchins which mostly found in rocky coastal areas and coral reefs spread across the Indo-Pacific region. Echinotrix calamaris has strong and sharp spines that can harm predators These sea urchins are difficult to be devoured by predators, leading to the presence of high Echinotrix calamaris.
The value of the diversity of sea urchin (H ') in Lemukutan Island ranged from 0.2632 -0.5465 the diversity (H') of sea urchins on Penata Besar Island is around 0.7726 -0.9083, whereas on Penata Kecil Island is approximately 0.9938 -1.2355 (Table 5). Of the three locations, the index value of the diversity of sea urchins on Penata Kecil Island is higher than Lemukutan Island and Penata Besar Island. The sea urchins on Penata Kecil Island fall into the category of medium diversity (1 -3), while Lemukutan Island and Penta Besar Island are at low density (<1) According Odum (1993), the value of diversity ranging from 0 to 1 included in the low category.
The low level of diversity in Lemukutan Island and Penata Besar Island was caused by the activity of tourist boat and fishing boat. The ship's propeller can damage the corals directly. In addition, the spillage of fossil fuel ships that contaminate marine waters also disrupts the activity and survival of sea urchins. Rumahlatu, (2011) stated that D. setosum is more tolerant of heavy metal pollutants in water areas due to ship activity. The Hutauruk study (2009) showed that Diadema density was found to be highest in areas which close to citizen settlements and ship belaying. The diversity of sea urchins on Penata Kecil Island has a medium category. This condition is due to the lack of community activities in taking and utilization of sea urchins around the area.
The dominance index (C) on Lemukutan Island was around 0.6704 -0.8121, while on Penata Besar Island was within 0.5448 -0.5535. It indicates that the dominance of sea urchins is is in medium category. The dominance number of sea urchins on Penata Kecil Island has ranged around 0.3795 -0.5281 yet it is included in the low category. This is in accordance with what was stated by Odum (1971) that if the number of dominance index closed to zero, so that there is not sea urchins which dominances in the waters. However, if the number of dominance index closed to one, there is absolutely a certain organism which dominate the area. The unity number (E) of sea urchins on Lemukutan Island has ranged around 0.8237 -0.3942, while the unity number of sea urchins on Penata Besar Island ranged around 0.5643 -0.7033 and in Penata Kecil Island ranged approximately 0.6175 -0.8237. According to Odum (1993), the smaller the value of uniformity index organisms then spread each type is not the same individual, but there is a trend is dominated by a particular type, and if the value of the index is the uniformity of the higher organisms then spread of individual each type of more uniform.
Environmental conditions in the waters influence any pattern of sea urchins Based on this research, the species of D. antillarium and E. calamaris on Lemukutan Island had a pattern of distribution around 0.6 -0.9. Equality of distribution patterns in the sea urchins caused by waters area which was overgrown with macroalgae. According to Coppard and Campbell (2005), D. antillarium and E. calamaris consuming macroalgae of Sargassum sp and Caulerpa sp that are living in coral reefs.
Species of D. setosum and D. savignyi have values of distribution patterns around 1.1 to 1.8 which means that the distribution patterns fall into clustered categories According to Nontji (2005), clustered life in the sea of sea urchins was also a special adaptation to protect themselves from predatory attacks, such as bloated fish with sharp teeth and sea crabs that can break the thorns and tear the shells of sea urchins with their claws.
Based on the results obtained in Penata Be-sar Island, D. savignyi species has a distribution pattern value of 0.9, classifies the distribution of sea urchins into prevalent distributed categories. This condition is caused by source food which is quite abundant one of them sea grass plants.
According to Setiabudi et al, (2016), an ideal habitat for the sea grass ecosystem it is located in the tidal zone, with shallow waters, ranging from 0 to 5 meters in depth. Nurdiansyah (2010) stated that the seagrass community located in the coastal area of Penata Besar Island composed by seagrass species such as Enhalus acoroides Seagrass of this species is the preferred feed by the sea urchins. Species of D. antillarium, D. setosum, E. deadema and E. calamaris have a clustered distribution pattern with a score around 1.1 to 4.7. The sea urchins from the four species were often found colonizing on sand substrate, coral and rocky boulders. This is clarified by Colin & Arneson (1995) statements that most of the sea urchins colonize around coral boulders and coral fractures so that sea urchins can hide among the coral gills.
Based on the results obtained, D. antillarium species, D. savignyi, D. setosum and E. deadema on Penata Kecil Island have a clustered distribution pattern with score around 1.2 -3.6 ( Table  47). The clustered distribution pattern in the sea urchins on Penata Kecil Island is influenced by open habitats that directly opposite the open-seas and waters such as sea water waves, so the sea urchins look for crevices to live inside. According to Sugiarto & Supardi (1995), sea urchins could generally live in clusters of dead coral holes and it can also increase the depth of the coral hole. It did it as an adaptation to face the influence of sea water waves in areas with currents. Species of E. calamaris has a score 1 of distribution pattern 1 which means it falls into a random category. The random distribution pattern occurred by the activity of sea urchins that often move to survive from predatory attacks (Aziz, 1987).
The brightness measured at all stations (on Lemukutan Island, Penata Besar and the Penata Kecil) was 100%. This indicates that the base of the waters can still be seen clearly from the surface. According to Hutabarat & Stewart (2000), the brightness of the clear waters would help the process of photosynthesis of seagrass and algae, so that the activity of sea urchins found frequently in the sunny waters of the overgrown plants.
The results of measurements of the depth on the Lemukutan Island was around 88.33-54 cm, on Penata besar Island was 58.33-71.66 cm, and on Penata Kecil Island was around 48-60.66 cm. According to Radjab (2004), the waters to a depth of 0.5-20 metres was suitable for sea urchins. They were also found at a depth of coral reef habitats overgrown by seagrass and algae, which were a macrohabitat favoured by sea urchins.
Water temperature on the Lemukutan, Penata Kecil and Penata Besar Island was around 27.33-32°C and air temperatures was around 29-32°C. Temperature on the Island still supports the life of sea urchins. Natural temperatures in coral cover and seagrass were ranged around 28 -32 ° C (MenLH, 2004).
The results of salinity measurements conducted on Lemukutan Island, Penata Besar and Penata Kecil Island showed the value of around 33 -35 %. The range of salinity found in every island still supports the life of sea urchins. According to Edward and Marasabessy (2003), salinity that supports the life of sea urchins is ranged from 31 -34.5 %.
Acidity level (pH) of the waters in each research location on Lemukutan Island, Penata Besar and Penata Kecil Island is 8. The pH's range in this study is in accordance with pH quality standard of the sea waters around 7 -8.5 which still supports the life of sea urchins (MenLH, 2004).
This research was conducted to support the efforts of the conservation of sea urchins in the area of intertidal waters and sea urchins is one of the indicators of sea water pollution in marine waters.

CONCLUSION
Sea urchins found in the research site were D. savignyi, D. antillarium, D. setosum, E. deadema, and E. calamaris Highest abundance of sea urchins was found in Lemukutan Island with 453 Ind/Ha of D. setosum. Lowest abundance was found in the Penata Kecil Island with 167 Ind/Ha of E. calamaris. The distribution of sea urchins in the Lemukutan and Penata Besar Island is in the category of clumped and evenly distributed. The diversity of sea urchins in the Penata Kecil Island is in medium category which range from 0.9938 to1.2355, while in the Lemukutan and Penata Besar Island is in the low category with the value of 0.2632-0.5465 and 0.7726-0.9083 respectively.