Class Bivalvia Research Articles

MACROZOOBENTHOS ABUNDANCE IN THE MANGROVE AREA OF TANAH MERAH SAMBOJA KUTAI KARTANEGARA EAST KALIMANTAN

Tanah Merah Beach is a coastal area of Samboja in East Kalimantan, which is a local tourist destination. The association of coastal ecosystems can be shown by macrozoobenthos, as one of the biota components in coastal areas to mangroves. This study identifies the species, calculates the abundance, and analyses the ecological index of macrozoobenthos, as well as looking at the relationship between nutrients and sediment texture with the number of macrozoobenthos found. The purpose of this research is to determine the condition of nutrients in the sediment substrate to its abundance in the mangrove ecosystem area. Sampling was conducted at three points based on the percentage of mangrove canopy cover in the Monmang version 2.0 application, with each point represented by 3 quadrant points measuring 0.25 m2. The results showed that the percentage of mangrove canopy cover was categorised as slight-moderate, the abundance of individuals was dominated by the Gastropoda class with 9 species and a small proportion of the Bivalve class. The ecological indices in order are the Diversity Index (H') in the low category, Diversity (E) in the low category, and dominance (C) found Cerithidae sp species dominating each point. The highest abundance was found at radius 2 canopy cover 77.24 - 83.13%. Nutrient content in sediment, nitrate (1.00-16.25 mg/L), phosphate (29.01-83.94 mg/L), organic carbon (2.23-3.24%) with confirmed sediment texture of sandy loam. Nitrate content ranged from 1.00-16.25 mg/L, Phosphate 34.65 - 44.51 mg/L and Organic carbon 2.23-3.24% (per mg) in the sediment and a significant effect of phosphate content on Macrozoobenthos abundance was found in the correlation test results.

Testing ultraconserved elements (UCEs) for phylogenetic inference across bivalves (Mollusca: Bivalvia)

Bivalves constitute an important resource for fisheries and as cultural objects. Bivalve phylogenetics has had a long tradition using both morphological and molecular characters, and genomic resources are available for a good number of commercially important species. However, relationships among bivalve families have been unstable and major conflicting results exist between mitogenomics and results based on Sanger-based amplicon sequencing or phylotranscriptomics. Here we design and test an ultraconserved elements probe set for the class Bivalvia with the aim to use hundreds of loci without the need to sequence full genomes or transcriptomes, which are expensive and complex to analyze, and to open bivalve phylogenetics to museum specimens. Our probe set successfully captured 1,513 UCEs for a total of 263,800 bp with an average length of 174.59 ± 3.44 per UCE (ranging from 28 to 842 bp). Phylogenetic testing of this UCE probe set across Bivalvia and within the family Donacidae using different data matrices and methods for phylogenetic inference shows promising results at multiple taxonomic levels. In addition, our probe set was able to capture large numbers of UCEs for museum specimens collected before 1900 and from DNAs properly stored, of which many museums and laboratories are well stocked. Overall, this constitutes a novel and useful resource for bivalve phylogenetics.

Intertidal Bivalve Diversity and Fishery of the Gosthani Estuary, Bhimunipatnam, Visakhapatnam, East Coast of India

The results of the present investigation revealed that the occurrence of 13 species belonging to class bivalvia were dominant taxa in the Gosthani estuary. Out of 13 species 6 orders, 8 families, and 11 genera were observed from April 2023 to March 2024. The samples were obtained by handpicking, digging, and trawling with bare feet by fisher community. A field survey was conducted to collect data on mollusc species, stocks, distribution, and marketing. The bivalves were collected from the bycatch for identification, mostly based on shell morphology, hinge, interlocking dentition, etc., with reference to the standard literature In this present study data was collected and analysed from fishermen community and traders. The Crassostrea madrasensis was more dominant availability species, its contributes to highest collection 5.867 T/ year and 2.78T in Apr-23, followed by Meretrix casta 2.78 T Meretrix meretrix 1.18 T, Anadara rhombea 0.87, Tegillarca granosa 0.759 and followed by other species. According to IUCN status 13 species contributed to 53.84% are not evaluated (NE), followed by data deficient (DD) with 30.76%, and least concerned 15.38%. The monthly available bivalves at Gosthani estuary the data was comparison for abundance. The difference between the sample averages of all groups is not big enough to be statistically significant. The results of ANOVA for p-value of 0.97 indicate significant support for H0. The p-value equals to 0.231 indicates a greater support for H0.

Freshwater Malacofauna and Distribution of Trabzon, Türkiye

In this study, freshwater molluscs and their zoogeographical distributions in Trabzon were investigated. During the period of June-December 2021, samples were collected from 38 freshwater river localities. From the study area, Ancylus fluviatilis from Gastropoda class, Planorbidae family, non-native species Physella acuta from Physidae family, and Dreissena polymorpha from Bivalvia class and Dreissenidae family were identified. While A. fluviatilis specimens were found from all freshwater systems in Trabzon region, the non native P. acuta could be identified from Fol Stream, Yıldızlı Stream, Sera Lake and Manahoz River. Empty shells belonging to the D. polymorpha species were identified from the area where Çatalzeytin Stream joins the sea. P. acuta and D. polymorpha are new records for the freshwater streams of Trabzon region.

The Diversity of Mollusks (Bivalve and Gastropod) in the Intertidal Zone of Mutun Coastal, Padang Cermin, Lampung

Mutun Coastal has a diversity of biota species. Biota that are commonly found include the mollusk phylum (Bivalve and Gastropod classes). The purpose of this study was to determine the diversity of mollusks (Bivalves and Gastropods) on Mutun Coastal Lampung. This research was conducted on February 5-7, 2021. The method of data retrieval at both stations used the belt transect method by purposive sampling. Station I is substrated fine sand, while station II is substrated by coarse sand. Based on the research conducted, 26 individuals were found consisting of 7 families, namely 6 families of the Gastropod class (Trochidae, Strombidae, Cerithiidae, Muricidae, Potamididae and Pisaniidae) and 1 family of the Bivalve class, namely the family Mactridae. The value (H') at station I is 1.44. At station II it has an H' value of 0.86. The value of H' at station I belongs to the medium category. The H' value at station II belongs to the low category. The value of E at station I is 0.72. While at station II it has a value of 0.1. The evenness value at station I belongs to the high category. The value (E) at station II of the evenness index belongs to the low category. The value (D) at station I is 0.57. While at station II it has a value of 0.35. The value of D at station I belongs to the medium category. The value of D at station II belongs to the medium category. Based on data analysis, Mutun Coastal has suitable habitat for mollusk and it is also supported by abiotic parameter conditions.

Mollusca Biodiversity as A Quality Bioindicator Waters in Central Lombok Gerupuk Bay Coastal Area

Various natural resource utilization activities on the coast of Gerupuk Bay can potentially affect the quality of the aquatic environment, both biotic and abiotic, one of which is mollusc biodiversity. This study aimed to determine the relationship between the existence of Mollusca biodiversity and water quality and substrate in Gerupuk Bay. This study used a quantitative descriptive method of determining stations using the purposive sampling method based on differences in community activities at each station. Sampling was conducted at three stations, including Mollusca samples and water quality measurements: salinity, pH, temperature, and substrate. Molluscs in Gerupuk Bay found 55 species of Mollusks representing three classes, namely the Gastropoda class, with as many as 44 species incorporated in 22 Families; the Bivalve class, as many as ten species contained in 6 Families; and the Scaphopoda class, with as many as one types incorporated in 1 Family. The composition of Mollusca classes found on the Gerupuk Bay Coast is Gastropoda class at 62%, Bivalve class at 35%, and Scaphopoda class at as much as 3%. Mollusca diversity is calculated using the Shannon-Wienner diversity index (H'). The diversity index results ranged from 2.890-1.998, with moderate categories at all stations. Bioindicators of water quality using the diversity index show that stations I and III categorize the Gerupuk Bay area as lightly polluted. In contrast, at station II, it is moderately polluted.

Checklist of the marine malacofauna of Culuccia Peninsula (NW Sardinia, Italy), with notes on relevant species.

Culuccia is a small peninsula of about 3 km2 placed in north-western Sardinia (Italy) at the margin of the Maddalena Archipelago. The marine area surrounding this Peninsula is a Special Area of Conservation, included in the European Natura 2000 Ecological Network of protected areas, but until now, no information on biodiversity of this area is available. In 2021, a research project to study both terrestrial and marine biodiversity of Culuccia has started in order to fill this gap of knowledge. This work provides the first inventory of the marine malacofauna of the coast of Culuccia. Fifteen sites were sampled seasonally for one-year by using different sampling methods and the present study shows the results from approximately 50 scientific SCUBA and free dive surveys, carried out in all main marine habitats of the studied area. In total, 259 species of molluscs were recorded along the coasts of the Culuccia Peninsula (0-25 m depth), belonging to the classes Bivalvia, Gastropoda, Polyplacophora and Scaphopoda. Amongst the four classes recorded, gastropods were the most represented (66.90%; 173 species), followed by bivalves (28.10%; 73 species), polyplacophorans (4.60%; 12 species) and scapophods (0.40%; 1 species). Notes about distribution, conservation status and ecology for some valuable species are provided, together with images of representative species, consisting mainly of in situ photographs. Additionally, the present investigation recorded the presence of four alien species, whose Mediterranean distribution was extended to north-western Sardinia.

Screening of Lactic Acid Bacteria from Oysters for Antibacterial Activity Against Selected Pathogens

Lactic acid bacteria (LAB) are among the important groups of bacteria and considered as probiotics development. LAB is mostly isolated from the gastrointestinal tract (GIT) from organism such as oyster. Oyster belongs in to class Bivalvia which live in estuaries area. The purpose of research was to isolate and screened for antibacterial activity against selected pathogens. The LAB was isolated by pour plate method using MRSA (De Man, Rogosa, Sharpe Agar) as selection media for LAB. Then, LAB was screened by an agar diffusion assay for antibacterial activity. The result showed that four isolates (TR-01; TR-02; TR-03 and TR-04) have inhibitory activity against pathogens including E. coli, Salmonella enterica, Staphylococcus aureus, Bacillus cereus. Therefore, it is needed further assay to selected 4 isolates as potential probiotics.

Bivalvia Community Structure in The Poton Bako Beach Area, Jerowaru, East Lombok

The bivalvia class is a class within mollusca that includes all types of shellfish that have a pair of shells. The aim of this research is to determine the structure of the bivalve community in the coastal waters of Poton Bako, East Lombok. This research was conducted on the coast of Poton Bako, Jerowaru, East Lombok. This research uses a proportional sampling method with quadratic transects. This research variable includes type and bivalves. In this study, 275 individuals of bivalve species were found. The research results show that the ecological condition of Poton Bako is in the relatively good category because the level of Bivalvia diversity is moderate at 1.38 with a high evenness index of 0.60 and a low dominance index of 1.13. In this research, it is necessary to carry out further research regarding distribution patterns, exploitation rates, characteristics of pemadak, and conservation efforts.

Macroinvertebrate assessment in seagrass ecosystem in Sinacaban Municipality, Misamis Occidental, Philippines

Abstract. Mahilac HMO, Tandingan JP, Torres AG, Amparado JRR, Roa-Quiaoit HA. 2023. Macroinvertebrate assessment in seagrass ecosystem in Sinacaban Municipality, Misamis Occidental, Philippines. Biodiversitas 24: 5586-5597. Marine ecosystems such as seagrasses are economically and ecologically important in tropical coastal areas like Sinacaban municipality, southern Philippines. This study assessed the macrobenthic species and water quality (e.g., pH, salinity, temperature, Dissolved Oxygen (DO), and total suspended solids (TSS) in three seagrass areas in the municipality. The study showed the seagrass habitats with 40 macrofaunal species from the classes Gastropoda (27), Bivalvia (11), and Crustacea (2), with Clibanarius longitarsus as the most abundant species (77 individuals or 24% relative abundance). The Strombidae family holds the highest dominance within the Gastropoda class, whereas the Arcidae family is the most dominant within the Bivalvia class. However, there is no dominant family within the Crustacea class. Water quality showed pH at 7, 30 ppt salinity, and 28? within their standard limits, while DO (8 mg/L) and TSS (127 mg/L) exceeded their range. This study recorded eight economic important species and five least concern International Union for Conservation of Nature (IUCN) species. Among the three (3) sites, the seagrass area in Libertad has the highest species richness (28), Shannon’s Index (2.92), and species evenness (0.66). The Chao estimation result revealed that Libertad (37.17) and Poblacion (18.5) have lower uncertainty in their species estimates than Colupan (39.60), which has a wider range of potential species richness. The Canonical Correspondence Analysis (CCA) proved that there are species that can adapt to a certain level of environmental parameters, like Angaria delphinus, while Decatopecten radula is one of the species that does not correlate with the water parameters in the study. The findings are critical for biodiversity conservation, ecosystem management, sustainable resource use, and adaptation to changing environments in order to maintain ecological balance and the long-term health of the seagrass ecosystem.

The characteristics of trimethylamine N-oxide content in different classes of marine animals over the coastal and offshore areas of China

Trimethylamine N-oxide (TMAO) is widely present in marine animals. However, the characteristics of TMAO content in different classes of marine animals are insufficiently understood. In this study, the TMAO content in 79 marine animals (48 species, 7 classes) collected in the coastal and offshore areas of China during year 2019–2022 was analysed. The results showed that the TMAO content of the total samples varied from 0 to 139.19 mmol kg−1. The TMAO content in the classes Bivalvia, Gastropoda, Polychaeta and Holothuroidea varied from 0.06 ± 0.09 to 0.38 ± 0.63 mmol kg−1, but it varied from 30.20 ± 24.20 to 75.90 ± 38.59 mmol kg−1 in the classes Crustacea, Cephalopoda, and Osteichthyes. The TMAO content in the latter 3 classes was 2–3 orders of magnitude higher than that of the former 4 classes. It was inferred that the significant difference was related to the food sources or physiological metabolic mechanisms of different classes.

Biodiversity and Distribution Patterns of Clams (Tridacninae) on Coral Reefs in Kayu Angin Bira Island, Indonesia

This research aims to find out the biodiversity and distribution patterns of clams and the relationship between clam abundance and coral reef conditions in the Waters of Kayu Angin Bira Island, Kepulauan Seribu. The research was conducted between April and July 2022, with field data collection taking place in September 2022 at four chosen stations. These stations were selected based on variations in water depth and were situated in the South, West, North, and East regions of the waters surrounding Kayu Angin Bira Island. The data collection was conducted using survey methods. Coral reef data collection using LIT (Line Intercept Transect) method and clam observation using belt transect. The results showed that in the waters of Bira Kayu Angin Island, 25 individuals of 2 species of bivalve class were found, namely Tridacna squamosa, Tridacna crocea. The highest relative abundance of clams is found at the eastern station which is 20% and the lowest relative abundance is found at the southern, western and northern stations which is only 8%. Low diversity index of Tridacninae Clams was discovered at the four stations, which ranged from 0.451 - 0.662 and the uniformity index at the four stations ranged from 0.650 - 0.954, indicates high population uniformity. Based on Morisita distribution index, which ranges from 0.4 - 0.74, the spatial distribution of Tridacninae clams could be assigned as uniform. The relationship between clams and coral reefs is 0.7284, shows that clams have a strong relationship with the condition of coral reefs.

The dynamics of microorganisms and their association with clam in fresh water ecosystem

Clams are shelled marine or fresh water mullusks belonging to the class Bivalvia. They are invertebrates with shells divided into two pieces called valves. They are rich source of proteins and minerals especially calcium and are recommended in the diet of pregnant women and in protein deficient cases. They inhabit the bottom of fresh water bodies or slow running waters. Fresh water is one which contain less than 0.5 parts per thousand of dissolved salts or other impurities, and are found in fresh water lakes, swamps and some rivers. The deposition of litter, substrates and other faecal materials in water body results in a build-up of pathogenic microorganism (bacteria) in the water which gives high burden on the water inhabitants including clams. The concentration of the bacteria in the water body varies with the season. This research was therefore aimed at accessing the type and density of bacteria and fungi present in fresh water associated with clams, and to determine the effect of the microorganism on the nutritional value of clams over a period of ten months in a fresh water ecosystem. Samples for analysis were water from Itu river, labeled sample A, sample B was water used to rinse the clams, sample C was homogenized clam intestine while sample D was homogenized body of the clam. The microbial load was determined using serial dilution and plating methods. Characterization and identification of microbial isolates was done using different standard biochemical tests, to determine; colonial morphology, Gram staining reaction, spore stain, motility, sugar fermentation, production of indole, coagulase and catalase. The methods as outlined by Association of Official Analytical Chemistry were used for physicochemical and nutritional analysis to test for moisture content, ash content, crude protein, fibre, fats and mineral elements. Results of the various analysis showed that, the total microbial count for the four samples through the ten months sampling period was highest in February with sample C having the highest of 1.2 X 105 cfu/mL, followed by sample D 7.0 X 104 cfu / mL, sample B had 5.8 X 104 cfu / mL while sample A was the lowest with 4.4 X 104 cfu / mL. The count was lowest in the month of September with C having 3.7 X 104 cfu / mL, followed by D with 2.4 X 104 cfu / mL, B had 8.0 X 103 cfu / mL while A the lowest was 4.0 X 103 cfu / mL. Microorganisms present in the fresh water sample and clam were mostly coliform from faecal matter and include; Staphylococcus aureus, Enterobacter aerogenes, Spirosoma lingual, Bacillus cereus, Lactobacillus plantarum, Escherichia coli, Flavobacterium aquatile and Micrococcus varians. We conclude that microbial load was higher in dry season than in rainy season probably due to dilution of the water and its velocity during rainy season. Results also showed that the nutritional values of the clam varies with season and density of microbial load. We recommend proper sanitation in water where clams are harvested and proper boiling of clams and possible removal of the intestine before consumption especially during the dry season.

Efficacy of Molecular Identification Using DNA Barcoding Technique of Freshwater Edible Molluscs from Nagaland, India

Freshwater molluscs are widely utilized for food and medicine in many regions of the world. One such area in India is the northeast, where tribal and economically underdeveloped communities consume freshwater molluscs. Because they are an inexpensive source of protein and offer food security, livelihoods, and medicine, these molluscs are in great demand. In the present work, molecular identification and documentation of the edible gastropods of Nagaland is done. Throughout the twentieth century, identification was based on morphology and anatomy. However, the identification based on morphological structure is challenging due to the existence of cryptic species that shows similar morphology which can lead to erroneous identification of species. Freshwater molluscs shells are highly varied and exhibit convergence evolution and hence may not always accurately indicate systematic boundaries. Thus, DNA bar-coding is a potential method for taxonomic identification process that can mitigate this problem. It uses genetic markers such as cytochrome oxidase I (COI) gene, 16S rDNA and 18S rDNA. In the present study COI mitochondrial gene is used. A fragment of COI gene is sequenced and their DNA is compared to the existing sequences in the genomic library. The sequence is then submitted in NCBI to obtain accession number. A total of 7 species of edible freshwater molluscs belonging to two class bivalvia and gastropoda was collected from local fishery ponds, confined water bodies, rivers, streams, and were identified. The identified species with their accession number is as follows, Lamellidens marginalis (ON209524), Parreysia corrugata (OM074301), Indonaia subclatharata (OM075118), Indonaia caerulea (OM076974), Bellamaya bengalensis (OM056888), Paludomus sp (OM078498), Brotia costula (OM056887). The study provides substantial support for COI's effectiveness as a prime marker for DNA barcoding of Indian edible freshwater gastropods and bivalves.

Identification of Mollusca Types Around Bungus Beach Padang

Mollusca animals have a soft body, not segmented, most of the shell is made of calcium carbonate. Taxonomic identification is carried out to find out the types of Mollusca animals as well as for collections. This research aims to determine the types of Mollusca animals around Bungus Beach Padang. This type of research is descriptive with roaming method. The cruising method is carried out by tracing the beach as far as the tides are ± 1 km long and 8 meters wide. Molluscs were taken directly for three times, and tested the water with physical and chemical factor parameters. The results obtained from the identification of Mollusca species found in the form of shells consisting of two classes, namely the Bivalvia class and the Gastropod class. The total number of individuals is 202 individuals. The most commonly found molluscs are the class Bivalvia with 17 species. The most abundant species and always found in each repetition was Soletellina diphos with 29 individuals, at least Meretrix lyrata, Barbatia fusca with 1 individual. Class Gastropods found as many as 14 species. The species most commonly found was Cypraea vitellus with 15 individuals, the least found were Cypraea leviathan, Murex trapa, Bufonaria rana, Turbo setosus, Pomacea sp., Phenacolepas sp. amounted to 1 individual. Identification of the types of Mollusca animals can be identified based on the morphology of their shells and can also match the Mollusca images that have been obtained with the identification book. From the results of this study it can be concluded that the identification of the types of Mollusca animals can be known based on the morphology of their shells and can also match the Mollusca images that have been obtained with identification books. The results of the research are recommended for further researchers to find the types of Mollusca animals as a whole, especially on the beach.

Malacofauna from Cappa Lombo Site: Environmental Reconstruction and Subsistence Strategies of The Bontocani Highland Karst Region, South Sulawesi

The remains of mollusk shell fragments are ecofacts that can explain the environmental conditions occupied by humans, especially in the context of the Holocene period in Sulawesi. This research answers questions related to the types of mollusks found in the cultural layer and aims to identify malacofauna remains at the Cappa Lombo site, Bontocani, South Sulawesi. The data collection method was carried out through excavation, and the analytical method involved taxonomic identification, external morphological identification, taxonomic classification, and documentation. This study successfully identified 10 families consisting of 15 genera and species. Terrestrial gastropod mollusks consist of the families Alycaeidae, Cyclophoridae, Ariophantidae, Dyakiidae, Clausiliidae, Achatinidae, and Camaenidae. Freshwater gastropods consist of 2 families, namely Pachychilidae and Viviparidae, while the bivalve class is only represented by the Cyrenidae family, which inhabits estuaries. Based on this identification, this research shows that the reconstruction of the environmental conditions around this site indicates a wet rainforest environment, which tends to be covered with vegetation and primary tropical forest. Additionally, during the occupancy period, there was a change in land use around this site. Data on the presence of mollusks also indicate consumption. Although mollusks were not a primary dietary source, humans during the Holocene at this site were able to utilize the aquatic environmental resources around the site they inhabited.

Macrozoobenthos Diversity on Mangkoso Beach in Barru Regency

Research on the diversity of Macrozoobenthos on the coast of Mangkoso village, Barru Sub-district in Barru district. The purpose of this research is to determine the diversity of Macrozoobentos. This research uses the purposive sampling method in determining the location of research stations and plot making using the line Transect method. The research station consists of three stations, i.e., Station 1, Station 2, and Station 3. The results of the study found 20 species of Macrozoobentos consisting of 13 species from Klas Gastropoda, from Classis Bivalvia 5 species, Polychaeta 1 species and Crustacea 1 species to a total of 20 species (Fillum Mollusca), Cerithium dialeum species, Cerithium sp, Clithon faba, Clithon oualaniense, Clithon sp, Hebra corticata, Hebra sp, Littorina sp, Nassarius bimacularus, Nerita sp, Smaragdia rangiana, Tornatina coarctata, and Vitta sp. Class Bivalvia consists of Anadara sp, Epicodakia sp, Spondylus sp, Tellina mariae, and Tellina sp. While Class Polychaeta, each one species is Naineris and Uca sp. The composition of the species, the population density, the negation, and uniformity of the community macrozoobenthos that the Station 2 is higher than Stations 1 and 3. It is seen on the results of the diversity index (H′) of Macrozoobentos at Station 1 (0.92) and Station 2 (2.55). All three stations indicate that low diversity and environmental quality conditions are in a half-polluted state. The seawater’s quality around the coastal Mangkoso village, Barru District, needs the local government’s attention to reduce environmental pollution.

Heavy Metal Content of Cadmium (Cd) and Chromium (Cr) in Green Mussels (Perna viridis) and Sediments of Sawojajar Waters, Brebes

Green mussel (Perna viridis) is one of the spesies in Bivalve class which filter the food particles from their surroundings. As filter feeder, it captured anything including plankton, detritus, and even heavy metals. Heavy metals content in green mussels could become dangerous due to the bioaccumulation process. This research aimed to determine the levels of heavy metals Cadmium (Cd) and Chromium (Cr) not only in the tissues of green mussels but also in the sediments of Sawojajar waters, Brebes; current study also determined the feasibility of green mussels for consumption in the perspective of food safety. The method used in this research was a field survey method which conducted in June 2022. The analysis method used AAS refers to the American Public Health Association (APHA) with laboratory tests conducted at the Productivity and Aquatic Environment Laboratory of IPB. The results showed that the content of heavy metal Cd in green mussel samples was at 0.19 mg.kg-1 which was meet the threshold concentration. Whereas, the heavy metal Cr in green mussels’ tissue exceeded the threshold of chromium concentration at 0.21 mg.kg-1. In addition, the heavy metal content of Cd and Cr in sediment were still meet the threshold concentration at 3.2 mg.kg-1 and 0.13 mg.kg-1 respectively. In terms of food safety, the EDI (Estiate Daily Intake) value based on the results of heavy metals Cd and Cr concentrations was 0.11 and 0.13 µg.kg-1.day-1 respectively. The result indicated that these heavy metals concentration had low risk in causing health issue. In the same way, the target hazard value (THQ) of Cd and Cr were not exceeded the RfD (Reference Dose) at 0.109 and 0.036 respectively. These value of THQ for both Cd and Cr indicated low risk in causing cancer and the green mussels are meet the food safety standard

KEANEKARAGAMAN KELAS BIVALVIA DI PANTAI CIBUAYA UJUNG GENTENG

Cibuaya Beach is one of the beaches in Ujung Genteng Village that is used as a tourist destination because the beach is still very clean and natural. Cibuaya Beach has large beach sand grains and is dominated by mollusk shell fragments. The intertidal zone is the zone bounded by the tidal line and is the narrowest of the marine zones. The coastal ecosystem of Cibuaya Beach consists of coral reefs, seagrasses, and coastal vegetation. This study aims to determine the diversity of Bivalves in Cibuaya Beach Ujung Genteng. This research was conducted at Cibuaya Beach Ujung Genteng in March-April 2022. Determination of the research location using the belt transect method by purposive sampling at three stations namely rocky sand (station 1), seagrass (station 2), and coral reef (station 3). The results obtained were 148 individuals with 11 Bivalve species comprising six families. The value of the diversity index (H') ranged from 1.58-1.99 classified as medium. The value of the evenness index (E) ranges from 0.83-0.88 classified as high. The dominance index value (D) ranges from 0.18-0.24 which is low. The measurement results of abiotic parameters, namely temperature, pH, salinity, humidity, current speed, and light intensity show good values for marine bivalve life. Therefore, the Cibuaya Beach intertidal ecosystem is suitable for the life of the Bivalve class.

Morphometric composition analysis of Sinanodonta woodiana based on depth stratification in Tributaries Meureubo West Aceh

Clams are aquatic biota that do not have a spine, belonging to the phylum Molluscs class Bivalvia. This study aims to determine the density, morphomteric differences of S. woodiana clams based on depth. The sampling technique used Purposive sampling method, with 1x1 meter plot and repetition 3 times. Data collection was carried out in July 2022 until completion. The results showed that the highest density of S. woodiana clams was found at a depth of 0-50 cm with an average density of 29.3 individuals/meter. Small size clams were dominantly found at a depth of 0-50 cm with a percentage reaching 97.92%, 54.46% of medium size clams were found at a depth of 50-100 cm, while 83.33% of large size clams were found at a depth of 100-150 cm. Anova test results showed significant differences with a 95% confidence interval. At a depth of 100-150 cm, the weight value of S. woodiana clams was 24.87 ± 3.36 grams, shell length 43.73 ± 1.21 cm, shell width 38.73 ± 1.76 cm, and umbo height 22.83 ± 0.76 cm. The results of this study can be concluded that the shallower the waters, the higher the density of shells, but the large size of the shells, the smaller the density.