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This study generally aimed to determine the spatial zonation and diversity of bivalves and gastropods in mangrove forest of Cozo, Esteves and Tinib in Casiguran, Aurora. Specifically, this aimed to determine the species composition and distribution, and determine the relationship between spatial zonation and diversity of bivalves and gastropods as influenced by ecological factors such as vegetation, soil texture, organic matter, soil salinity, and soil pH. A total of 22 taxa comprising eight species of bivalves and 14 species of gastropods were identified. The high tidal zone of Esteves had high diversity (0.66) of bivalve species compared to other tidal zones and areas. On the other hand, the diversity of gastropods was almost equal in the middle tidal zones of Cozo (0.60), Esteves (0.57), and Tinib (0.42). In terms of bivalve species’ density and abundance, Dendostrea folium was the most dense and abundant in the low tidal zone of Cozo (253,333 ind.ha−1 or 25 ind.m2-1, 97.44%) while Gafrarium tumidum in the low tidal zones of Esteves (46,666 ind.ha−1 or 4 ind.m2-1, 73.68%) and Tinib (126,666 ind.ha−1 or 12 ind.m2-1, 50%). In terms of gastropod species’ density and abundance, Cerithidea cingulata was the most dense and abundant in the low tidal zone (666,666 ind.ha−1 or 66 ind.m2-1, 65.79%) of Cozo and the middle tidal zone (5,280,000 ind.ha−1 or 528 ind.m2-1, 61.40%) of Tinib. It was Terebralia palustris in the low tidal zone (1,263,333 ind.ha−1 or 126 ind.m2-1, 63.06%) of Esteves. All tidal zones within each study area had greater dissimilarities in terms of bivalves but had greater similarities in terms of gastropod species’ compositions. On the other hand, all tidal zones between study areas had greater dissimilarities in terms of bivalve and gastropod species present. Most tidal zones had Gafrarium tumidum as common bivalve species while Neritidae sp. and Cerithidea cingulata were common gastropod species. All these species were found thriving in a wide range of vegetation, soil texture, organic matter, soil salinity and pH.

Mangrove snail, Terebralia palustris Linnnaeus 1967, was also found on Pannikiang Island, Barru Regency, South Sulawesi. This study aims to describe the fluctuation of T. palustris density in a year of observation. This research was conducted for ten months from August 2018 to July 2019. There were two research stations. Each station has a large plot measuring 10m x 10m and in it, five small plots are measuring 1m x 1m. Measurements of environmental parameters such as temperature, salinity, and pH were carried out in situ. This snail meat as much as 100gr also analyzed proximate. The proximate analysis of the snail shows that crude protein content is 18.73% so that the snail is very suitable to be used as a source of protein. The highest density is in July 2019 and the lowest density is in August 2018.

The diversity and abundance of bivalves and gastropods were studied from April to July 2015. Two sampling stations, Tinib and Esteves, in Casiguran, Aurora were selected based on the presence of mangrove forest, bivalves, gastropods, muddy substrate, and gleaners for the establishment of a transect line. Each station was laid with 100 meters transect line overlaid continuously with 2 m × 2 m quadrat along each transect. A total of 50 sampling units covering 0.02 ha area per sampling station were surveyed. The transect line recorded six species of bivalves distributed among five families and 12 species of gastropods belonging to eight families. Three species of bivalves and five species of gastropods were common to both sampling stations. However, Tinib station had most diverse species of bivalves (0.55) while Esteves station had most diverse species of gastropods (0.43). Both stations revealed Dendrostrea folium (43%) (bivalve) and Cerithidea cingulata (93%) (gastropods) as most frequently occurring species. Dendostrea folium also emerged as the densest (10,640 ind∙ha−1 and 6850 ind∙ha−1) and most abundant (58.52% and 77.84%) bivalve species. For gastropods, Terebralia sulcata (249,250 ind∙ha−1) was the densest and most abundant (96.97%) in Tinib while Terebralia palustris was the densest (747,050 ind∙ha−1) and most abundant (70.44%) in Esteves. Pooled results for bivalve species maintained Dendrostrea folium as the densest (8750 ind∙ha−1) and most abundant (64.81%). However, for gastropods, Terebralia palustris emerged as the densest (373,525 ind∙ha−1) and most abundant (56.70%) species. The mangrove forests of Casiguran, Aurora thus contain a variety of bivalves and gastropods with Tinib station dominated by bivalves while Esteves station dominated by gastropods.

The community composition of benthic macrofauna and relationships between physiochemical parameters of the water and sediment texture were assessed in Hara Biosphere Reserve, Northern Persian Gulf. The spatial distribution and diversity of macrobenthos were sampled within three distinctive mangrove zones (deltaic, island and coastal) during two sampling seasons between August 2014 and January 2015. A total of nine transects perpendicular to the coastline were selected to cover over the entire study area. The counts of all macrofauna were recorded from each zone and station with three replicate sediment samples. The snails, Cerithidea cingulata and Asseminea sp., were observed throughout three mangrove zones, but their abundance varied among habitats. The bivalve Dosinia ceylonica found to be more abundant in delta, whereas burrowing crabs Ocypode and Uca were dominate in coastal zone. Terebralia palustris and amphipods were recorded frequently in island zone. The nonmetric multidimensional scaling ordinations and a three-way factor PERMANOVA indicated that macro-invertebrate species composition significantly differed among different mangrove zones. The results also showed the seasonal variations. The findings of diversity indices illustrated that deltaic zone had the highest abundance and diversity, while the coastal zone showed the lowest values among the three zones. Taken together, the observations demonstrated that the different hydrological conditions, temperature, salinity and sediment texture were the main factors determining dispersion of benthic faunal assemblages among different mangrove habitats at Hara Biosphere Reserve. There is a need to consider such variables in ecological studies to understand differences of macrofaunal diversities in these complex habitats.

Setyadi G, Rahayu DL, Pribadi R, Hartati R, Wijayanti DP, Sugianto DN, Darmawan A. 2021. Crustacean and mollusk species diversity and abundance in the mangrove communities of Mimika District, Papua, Indonesia. Biodiversitas 22: 4146-4157. A mangrove crustacean and mollusk species diversity study was carried out in four mangrove estuaries in Mimika District, Papua, Indonesia. Two locations were selected on each estuary; for each location, samples of crustaceans and mollusks were collected from 5 m × 5 m plots, and mangrove trees were recorded on 10 m × 10 m plots at a distance of 10 m, 250 m and 500 m perpendicular to the riverbank. This study recorded a total of 41 species of crustaceans and 32 species of mollusks the latter comprising three species of bivalves and 29 gastropod species. The number of crab species found was among the highest compared to similar studies in the world. The average number of species collected from each 25 m2 plot was 7.6 ± 4.2 species for crustaceans, with an average abundance of 87 ± 3.5 individuals; for mollusks, it was 3.3 ± 3 species with an average abundance of 28 ± 48.4. Crustacean abundance and species composition were influenced by inundation frequency. There was a strong correlation between the crab Parasesarma cricotum and the association of Rhizophora apiculata and Bruguiera gymnorrhiza mangroves, and Clistocoeloma amamaparense and the association of B. gymnorrhiza, R. apiculata, and Bruguiera parviflora mangroves. For mollusks, correlations were found between Terebralia palustris and Ellobium aurisjudae and the association of R. apiculata and B. parviflora mangroves. The highest crustacean Shannon-Wiener diversity index was associated with Sonneratia alba and Avicennia marina mangroves, and the highest mollusk Shannon-Wiener diversity index was associated with R. apiculata and B. gymnorrhiza mangroves.

The study assessed the structure, natural regeneration capacity and Biotic agents of Avicennia marina and Bruguiera gymnorrhiza species in Mida creek, Kilifi County. The study used both cross section and descriptive research design. Avicennia marina species was more dominant with a greater complexity index (A2.7, B0.4), basal area (A588cm2, B484cm2) and mean height (A26m, B10m) compared to Bruguiera gymnorrhiza species with both having an aggregate dispersion pattern. During dry season, Height, and diameter of Avicennia marina had a correlation of 0.56 while Bruguiera gymnorrhiza species had 0.78. During rainy season both had a correlation of 0.67. B. gymnorrhiza species had more straight poles than A. marina species, 75.3% of B. gymnorrhiza trees assessed had straight pole compared to 1.7% of Avicennia marina trees. Both Avicennia marina and Bruguiera gymnorrhiza species had fair regeneration capacity where the number of seedlings was greater than saplings and number of saplings was less than mature trees. Littoraria scabra fed mostly on micro-organisms and algae, Littoraria Glabrata fed mostly on mud surface, Sesarma guttata and Sesarma leptosoma fed on mangrove leaves, Cerithidea decollata fed on deposits and organic matter, Terebralia palustris and Selatium elongatium fed more on algae and leaves, Sesasrmi ortmanni, Metopograpsus oceanicus and Neosarmatium meinerti fed on leaves and young propagules, Barnacles and Oyster bunch on the roots and stems of B. gymnorrhiza species. Biotic agents were insignificant in affecting regeneration capacity of A. marina and B. gymnorrhiza species however combinations with climatic and anthropogenic factors affected Regeneration capacity of the two species.

Ginantra IK, Muksin IK, Suaskara IBM, Joni M. 2020. Diversity and distribution of mollusks at three zones of mangrove in Pejarakan, Bali, Indonesia. Biodiversitas 21: 4636-4643. The diversity of mangrove species in mangrove zonations on the coast of Pejarakan plays an important role in the existence of faunal diversity, including those from mollusks. Mollusks are the dominant phylum associated with mangrove habitats, in addition to the species of the Crustacean subphylum. This research aimed to determine the diversity of mollusks and their distribution patterns in three mangrove zones in Pejarakan, Buleleng District, Bali Province, Indonesia. Data collection was conducted by establishing sampling plots across three mangrove zones, i.e. seaward zone, middle zone, and landward zone. There were 23 sampling plots in total with size of each plot was 1x1m. The species and number of individuals of each species of mollusks were recorded in each quadrat plot. The diversity of mollusks was calculated using the Shannon-Wiener index, evenness index, and dominance index, while the pattern of distribution of mollusks was measured using the Morisita index. The results of the study found 27 species of mollusks, consisting of 19 species from Gastropods group, 7 species from Bivalvia group and 1 species from Polyplacophora (chiton). The seaward zone showed the highest species diversity, while the landward zone had the lowest. Terebralia palustris had the highest abundance with 217 individuals/m2 and was distributed in the three mangrove zones. Planaxis sulcatus showed the highest abundance (87 ind./m2) in the seaward zone, and Telescopium telescopium showed a fairly high abundance and were distributed in the mid zone and the landward zone. In general, mollusks in the mangrove area of Pejarakan was distributed in a group/clustered pattern. The data from this research can serve as a reference in mangrove forest conservation efforts and mangrove forest used for ecotourism.

The aim of this research was to determine the composition, domination, and diversity of benthic gastropod in three coastal condition of West Bali National Park, Province Bali. This research conducted with transect method. The research datas were raised at three location with different type of substrate, there are Prapat Agung Beach, Karang Sewu Beach, and Cekik Beach. The substrate type was rough sand, cobble, and smooth sand. Every location has two transect which is upright the contur and then has a few plot too with the measure of every plot is 1 m2. The interval for every transect is 100 m, while for every plot is 10 m. Ponar dredge was use to raised benthic gastropod. Identification of benthic gastropod was refer to identification key. The result of this research showed that 25 species from 14 family of gastropod founded at three coastal condition. Euplica scripta was dominated in the first location with index of domination is 57,14%, Terebralia palustris was dominated in the second location with index of domination is 93,46%, and Hastula hectica was dominated in the third location with index of domination is 100%. According to the result, we can conclude that composition, domination, and diversity of benthic gastropod are interrelated with substrate type of the coastal.

This publication aims to shed light on the influence that prior heating (burning) of mollusc shells during human activity may have on the results of radiocarbon dating. We compare the geochemical and mineralogical composition of heated and unheated shells of Anadara uropigimelana and Terebralia palustris recovered from Neolithic and Bronze Age archaeological contexts at Kalba, Sharjah Emirate, in the United Arab Emirates (UAE). Our research examined whether the heating of shells impacts on the determination of reservoir effects, or whether in spite of heating, this material remains a viable material for precise 14C measurements. Our results show that both heated and non-heated shells of A. uropigimelana and T. palustris provide consistent results, although the mineral composition of the shells changes from aragonite to calcite. Our results are important, since some of our selection of shells did not initially appear to have been heated. A heating process will then usually be detected as a greyish, marble like structure when cutting the shells. As a result of this work, we have also developed insights into prehistoric cooking practices of shells collected in Arabia. Our results provide archaeologists and associated researchers with confidence when assessing the results of radiocarbon dating during their studies of shells that might have been heated.

To investigate gene-flow patterns in the western Indian Ocean (WIO), tissue samples of Terebralia palustris were collected along the coasts of East Africa and Madagascar. A fragment of the mitochondrial cyto- chrome c oxidase subunit I (COI) gene was sequenced in 308 individuals from 18 sites. Based on a COI fragment of 624 base pairs, 43 haplotypes were identified. The two most abundant haplotypes were shared among all sample sites, but 20.9% of the haplotypes were restricted to the sites in southern Mozambique. Population expansion was found and confirmed by moderate haplotype diversity, low nucleotide diversity and the analysis of demographic history. Analysis of molecular variances (AMOVA) revealed significant genetic differentiation among populations (φst = 0.10, P ≤ 0.001). Pairwise φst and a hierarchical AMOVA (φct = 0.04, P = 0.01) suggest significant genetic differentiation among five regions: (1) northern Kenya, (2) Kenya, Tanzania and western Madagascar, (3) northeastern Madagascar, (4) southern Madagascar and (5) southern Mozambique. Since the analysis of isolation by distance did not show a sig- nificant correlation between geographic distance and genetic differentiation, even though the maximum distance between sites is about 3,050 km (Z = 7,513.89, r = 0.12, P = 0.08), the complex oceanography in the WIO could be the main factor that restricts gene flow.

We investigate the local marine reservoir effect at Kalba, United Arab Emirates (UAE), between the Neolithic and Bronze Age with respect to possible changes through time and mollusk species diversity. Two distinctive species living in close proximity to the mangrove of Khor Kalba provide insights into ocean circulation patterns in this coastal environment. The species selected are the bivalve Anadara uropigimelana, and the gastropod Terebralia palustris. They have been an important local food resource for humans since at least the Neolithic. Our results show that for the Neolithic and Bronze Age, the reservoir effects ΔR are quite different for the species selected. For Anadara spp. the ΔR decreases from 576 ± 90 to 112 ± 44 years, while for Terebralia spp. the reduction ranges from 389 ± 66 to −19 ± 36 years. These results are coeval with other multi-proxies (stalagmite records and sea level changes) for the middle Holocene, and suggest that the main cause of the decreasing reservoir effect is a changing – in this case declining - sea level and an increasingly drier climate.

Mangrove gastropods are largely recognised for their roles as benthic deposit feeders that consume macrophyte-derived detritus. However, microalgae may also make a significant contribution towards the diet of these snails. Here we provide the first report on the rates at which microphytobenthos (MPB) is consumed by Terebralia palustris, an Indo-Pacific mangrove gastropod. Although juvenile T. palustris are generally detritivorous, there is increasing evidence that their occurrence on the seaward edge of the mangrove habitat allows them to incorporate a more nutritious food source to their diets in the form of microalgae. Using an experimental approach that incorporated fluorometric techniques, we found that the feeding activity of T. palustris on MPB was not clearly related to diel and tidal cycles at the subtropical location of Kosi Bay, South Africa during two sampling occasions in February and July 2015. However, a faster ingestion rate and higher consumption/digestion efficiency were recorded ...

Indonesia has a high diversity of marine life, including gastropods. The distribution of gastropods varies in various locations at sea such as at the location of seaweed cultivation in Suppa Regency. These types of gastropods have not been identified even though the public knows the benefits of this organism. Therefore, efforts are needed to inventory these types of gastropods. The purpose of this study was to determine Gastropods living together in seaweed aquaculture locations (Eucheuma sp) in Suppa District. This research uses free roaming techniques along the seaweed cultivation location. The population is all types of gastropods that live together in seaweed farming locations. Samples are types of gastropods found at seaweed farming locations. Samples of abiotic and biotic factors along seaweed farming locations are also recorded as supporting inventory data. Gastropods were found there were 9 (nine) types that came from 8 (eight) genera, 5 (five) families. There are 3 species found in all sampling points, namely Cerithidea cingulata, Terebralia sulcata, and Terebralia palustris. Species found in certain locations and not found in other locations are Telecospium telecospium, Faunus ater, Rhinoclavis vertagus, Strombus microurceus, Nerita insculpta, and Monodonta labio. The suggestion of this research is to periodically observe the diversity of gastropod species in seaweed cultivation locations to determine patterns of interaction between organisms and the environment that occur seaweed cultivation locations.Keywords: gastropods, seaweed, pinrang district

We recently started a systematic approach to determine the reservoir age in southeast Arabia and its dependence on mollusk species and their environment. This part of the study concentrates on local reservoir age and stable isotopes of the lagoonal species Terebralia palustris and Anadara uropigimelana at Khor Kalba, Oman Sea. Environmental and nutritive influences on mollusks are reflected in the radiocarbon and stable isotope signal. We found a local reservoir age of A. uropigimelana of about 940 yr and that of T. palustris as 800 yr. Sclerochronological analyses yielded information about seasonality of growth and death in A. uropigimelana. The modern shell of Periglypta reticulata shares food resources and habitat with Anadara sp., of which we did not find a modern specimen. It provided information on response to changes in temperature in the lagoonal system needed for suitability as reflecting climatic conditions. We were interested in carbon pathways of the mangrove in Kalba and a mangrove planted anew on a former mangrove sediment in Ajman. Being an obvious source of charcoal and food of T. palustris makes this information necessary. Further analyses will be performed to interpret changes in reservoir age in complex lagoonal systems as reaction to environmental variability.

Terebralia palustris is a snail that lives in the mangrove ecosystem. This snail is found around the mangrove roots. Snail fecundity is also influenced by several factors. This study aims to determine the association of fecundity with morphometrics and environmental factors. sampling is done randomly. The research station is 2. Each station has one plot measuring 10 m x 10 m and in it, there is a small plot measuring 0.5 m x 0.5 m in 4 pieces. Data were analyzed by regression using SPSS version 21 software. The average fecundity of snails in September was 85887.64 granules, October was 45962.67 granules, and November was 35668.62 granules. The average temperature of seawater is 35.20 ± 0.16 ˚C, the average salinity of seawater is 32.27 ± 0.63 ‰, and the average pH of seawater is 6.39 ± 0.09. The results of the regression analysis showed signs that the snail morphometry of T. palustris did not affect snail fecundity because the significance value was far above 0.05. The results of the regression analysis showed that acidity factors significantly affected fecundity with a significance value of 0.047 and the other factors is not affect.

Archaeological shell middens are particularly important for reconstructing prehistoric human subsistence strategies. However, very little is known about shellfish processing, especially when related to the use of fire for dietary and disposal purposes. To shed light on prehistoric food processing techniques, an experimental study was undertaken on modern gastropod shells (Phorcus lineatus). The shells were exposed to high temperatures (200–700 °C) to investigate subsequent mineralogy and macro- and microstructural changes. Afterwards, the three-pronged approach was applied to archaeological shells from Haua Fteah cave, Libya (Phorcus turbinatus) and from shell midden sites in the United Arab Emirates (Anadara uropigimelana and Terebralia palustris) to determine exposure temperatures. Results indicated that shells from the Haua Fteah were exposed to high temperatures (600–700 °C) during the Mesolithic period (ca. 12.7–9 ka), whereas specimens from the Neolithic period (ca. 8.5–5.4 ka) were mainly exposed to lower temperatures (300–500 °C). The thermally-induced changes in A. uropigimelana and T. palustris shells from the South East Arabian archaeological sites were similar to those seen in Phorcus spp. suggesting a broad applicability of the experimental results at an interspecific level. Although heat significantly altered the appearance and mineralogy of the shells, 14CAMS ages obtained on burnt shells fit within the expected age ranges for their associated archaeological contexts, indicating that robust radiocarbon ages may still be obtained from burnt shells. Our study indicates that the combination of microstructural and mineralogical observations can provide important information to infer shellfish processing strategies in prehistoric cultures and their change through time.

Mangrove gastropods and hermit crabs are frequently harvested for use as bait by artisanal trap and hook fishers, along the Kenyan coastline and elsewhere. In addition to mangrove degradation, the harvesting of shelled invertebrates, can alter shell availability and hence survival of these interdependent fauna. This study compares shell morphometric characteristics such as shell availability, adequacy and bait yield, among sites with different patterns of bait harvesting and other human disturbances. Shell morphometrics are also related to mangrove forest stand characteristics such as forest complexity, dominance, cutting intensity and sapling regeneration. Results indicate that the sampling regime, hermit crab taxa and mangrove zone influence morphometric characters of the gastropod and hermit crab. Significantly higher (P

The study assessed climate change adaptation options and their implications on mangrove resources in Bagamoyo District. A total of three villages and 158 respondents were involved. Close and open-ended questions and FGDs were used to collect quantitative and qualitative data. Descriptive and content analysis was used for qualitative data while SPSS (Version 20) and Microsoft excel were used for quantitative data analysis. Results indicated that, majority of respondents (>80%) were aware of the climate changes and majority perceived rainfall (Kaole 72.7%, Kondo 70% and Mbegani 43.9%) as a major climate change indicator. Analysis of the empirical data from TMA showed a decline of rainfall (y = -3.8748x + 978.1) and an increase of earth’s surface temperature of an average of 0.8°C (y = 0.4142x + 21.655) from 1985-2015. Unpredictable and shortage of rainfall and increased earth’s surface temperature in combination acted to reduce agricultural yields and fish catch in the surveyed villages. Different climate change adaptation strategies identified in the surveyed villages include; expansion of farms, modifying fishing activities and engagement into different income generating activities such as casual labour, and petty businesses. The identified adaptation options in Kaole seemed to have positive implications on mangroves resources i.e. effective mangrove restoration programmes while those identified in Mbegani and Kondo i.e. weak mangrove restoration programmes, commercial firewood and charcoal making were unsustainable and had negative implications on mangroves resources. Further studies on climate change adaptation, awareness raising and scientific studies on mangroves species composition, richness and restoration in a changing climate are recommended to enhance coastal community adaptive capacity and effective management of coastal resources.

Research into the role of Terebralia snail in the storage of carbon at mangrove Pulau Panjang was performed from November to December 2013. The mangrove was located in the intertidal part which is affected by a low tide of the sea. When collecting the data, we made 30 quadrants with a 0.25 × 0.25 m size, which was determined at random. The measured data were Terebralia density (T. palustris and T. sulcata) and the carbon content in the whole body. The results of the study showed that Terebralia palustris has the highest density of 25 individual/m2, while Terebralia sulcata has the lowest density of 15 individual/m2. The percentage of carbon content stored in the body of T. palustris ranged from 16.27 to 18.89 % with an average of 17.45%, while the carbon stored in the body of T. sulcata ranged from 15.98 to 17.62 % with an average of 16.87%. Potential carbon storage by T. palustris and T. sulcata was 4374 g C/m2 and 2609 g C/m2, respectively.

In this study, metal and metalloid concentrations and pathogens were measured in shellfish at different locations in a tropical estuary, including sites impacted by sewage and industry. Oyster, mangrove snails and mud snails did not exceed Australian and New Zealand Food Standards maximum levels for copper, lead or estimated inorganic arsenic at any site although copper concentrations in oysters and mud snails exceeded generally expected levels at some locations. Bacterial community composition in shellfish was species-specific regardless of location and different to the surrounding water and sediment. In the snails Telescopium telescopium, Terebralia palustris and Nerita balteata, some bacterial taxa differed between sites, but not in Saccostrea cucullata oysters. The abundance of potential human pathogens was very low and pathogen abundance or diversity was not associated with site classification, i.e. sewage impact, industry impact and reference.

Cellulase and hemicellulases (mannanase, xylanase, xyloglucanase, and licheninase) activities were measured in the extracts of 18 species of macrobenthos (an oligochaete, two polychaetes, two decapods, one amphipod, three bivalves, and nine gastropods) to check the relevance of macrobenthos to the breakdown process of hard-degradable carbohydrates derived from terrestrial plants. As a result, these enzyme activities were detected in all of the extracts of macrobenthos except for Tubificidae sp. High cellulase activities were detected in the extracts of the decapods (Neocaridina denticulate denticulate, Caridina multidentata) and the gastropods (Semisulcospira libertina, S. reiniana, Physa acuta, Terebralia palustris). However, only weak activities were detected in the polychaetes (Perinereis nuntia, P. aibuhitensis) and the bivalve (Ruditapes philippinarum). High mannanase and licheninase activities were detected in two decapod species (N. denticulate, C. multidentata), while high xylanase activities were seen in the gastropods (S. libertina, S. reiniana). High xyloglucanase activities were noted in the gastropod (T. palustris). These facts suggest that the activities of different types of hemicellulase were distributed rather unevenly among the macrobenthos. The present paper is the first to report the widespread distribution of cellulase and hemicellulase activities among ecologically important aquatic invertebrates, and the possible relevance of these species in the breakdown process of plant-derived hard-degradable carbohydrates.

Research on the characteristics of Mangrove Crab Habit ( Scylla sp) in Silang Cadek Mangrove Ecosystem, Baitussalam Subdistrict, Aceh Besar District, Aceh Province. This study aims to determine the habitat characteristics of Mangrove Crab ( Scylla sp) in the Mangrove Ecosystem of Silang Cadek. The research method is survey with purposive sampling technique. The results of the survey are described. The results of the research showed that the water temperature data ranged from 22 s.d 25°C, the pH ranged from 7.5 to 7.7, the water salinity ranged from 30‰ -34‰. Substrate loamy sand, sandy loam, sandy clay loam. There are 4 constituent species of mangrove plants namely Bruguiera gymnorrhiza , Rhizopora stylosa , Rhizopora apiculata , Avicennia marina . Macrozoobenthos found were Nerita lineata , Uca crassipes , Terebralia palustris , Terebralia sulcata , Isognomon ephippium , Saccostrea cucculata , Uca demani , Scylla serrata , Scylla olivacea, Scylla paramamosain .

The effect of different sewage concentrations (0, 20, 60 and 100%), vegetation (Bare, Avicennia marina or Rhizophora mucronata) and immersion periods (immersion/emersion period of 12/12 h or 3/3 days just for 100%) conditions were studied for 6 months on survival and growth rates of Terebralia palustris (Linnaeus, 1767). Gastropods' activity and ecosystem engineering preformed at bare and A. marina planted cells and 3 sewage conditions (0, 20 and 60%) were determined. Survival rates were higher than 70% in all treatments. Growth rate decreased significantly with increasing sewage concentrations (mainly at unplanted conditions) and longer immersion periods. A complete shift (from immersion to emersion periods) and a significant decrease in mobility and consequently its engineer potential, due to sewage contamination, lead to a 3-4 fold decrease in the amount of sediment disturbed. Sewage contamination, primary producers' abundance and environmental conditions may have influenced the gastropods survival, growth and its ecosystem engineering potential.

The gastropod T. palustris is one of the major species responsible for leaf consumption and degration within the Indo-Pacific mangrove forests, and it strongly competes with herbivorous sesarmid crabs in consuming fallen leaves. This snail feeds at high and low tides and it is able to locate food items by means of chemical cues. The aim of this study was to assess the food preferences of T. palustris and to define its feeding strategies at low and high tides, by conducting field trials on water-borne mediated food location at high tide, grazing rate and the chemical attraction exerted by different mangrove leaves. The results showed that T. palustris was able to perceive underwater grazed leaves. In addition, we demonstrated that T. palustris consumes all the mangrove species (preferentially the Rhizophoraceae leaves) but Xilocarpus granatum. Moreover, this snail is differentially attracted to different mangrove species: the major attractive power is wielded by the rhizophoracean species and Pemphis acidula, while X. granatum does not attract this snail at all. The efficacy and adaptive value of a chemically mediated food searching strategies is unquestionable since by using this ability T. palustris can locate and reach the leaves it preferentially consumes. Moreover, T. palustris is the only macrobenthic species of East Africa mangroves able to search, detect and consume mangrove leaves at both high and low tides. Such an expanded feeding window permits T. palustris to occupy temporal niches left empty by the sesarmid crabs.

A dense population of Terebralia palustris occurs in many coral islands in the Jakarta Bay area, living usually in association with mangrove communities. A preliminary study on this gastropod has been carried out in two islands, Pulau Rambut and Pulau Burung, which concerned with population density and structure, length-weight relationship, rate of growth, and the effect of prolonged desiccation and starvation. Analyses were made on the properties of the substrate including soil component, organic matter content, pH, salinity, and daily temperature fluctuation at the soil's surface.No less than 130 specimens per square meter were counted in the most densely populated place in Pulau Rambut. The length frequency distribution showed a bimodal histogram, and the length-weight relationship was represented by the following equation: W = 0.00024 L2'5534 where : W = dry weight in gram; L = length in milimeter.A number of young individuals were confined in a fenced area for growth study. During the first four-month they gained an average additional length of 10 mm. Out of water and starved this gastropod may survive for three months.

Although the role of macroinvertebrates in the nutrient cycling of the Indo-Pacific mangrove ecosystems is now a paradigm of ecological research, most of the research and scientific assumptions deal with decapod crustaceans alone. However, decapods are not the only representatives of mangrove macrobenthos and in certain mangals they are surely outnumbered by gastropods, especially by potamidids of the genus Terebralia. This paper aims at bridging the gap in the knowledge of the ecological role of the largest and most abundant potamidid species of the Indo-Pacific mangals, the semiterrestrial T. palustris. In particular we studied size structure and distribution in relation to micro-environmental factors and feeding ecology, both in terms of diet composition and grazing rate, of two populations of this gastropod colonising a Kenyan mangrove creek. In contrast to what has been described by various authors concerning other mangals, in our study site juveniles and adults of T. palustris were present throughout the whole forest, from the landward belt to the seaward fringe, locally reaching very high densities at various levels. Both life stages showed a preference for patches characterised by soil with high organic content; thus the habitat of juveniles largely overlapped with that of the adults, although they are known to occupy different ecological niches. Indeed, gut-content analysis confirmed that juveniles are detritivorous and adults are mainly leaf-litter consumers. In situ experiments on the grazing activity of the adult snails showed that, in contrast to the litter-consuming crabs, they feed in every light and tidal condition, for an hourly consumption rate of ~0.65 g per snail. Considering an average density of about 10.5 adults m−2, it is estimated that a total of 10.5 leaves m−2 are removed by adult snails in each tidal cycle (i.e. about every 6 h). T. palustris is the only leaf consumer capable of searching for food under water during high tide and is responsible for the removal of a great quantity of mangrove litter. The results of the present study strongly suggest that T. palustris plays a major role in the food web, mangrove litter degradation and nutrient cycling of the Kenyan mangal.

The sediment surface within the Osbornia belt of a mangal on Pulau Hoga, Tukang Besi Islands, Sulawesi, Indonesia, is dominated inter alia by deposit-feeding gastropod molluscs at a mean density of some 230 ind m−2 although, unusually, species of Cerithidea do not occur. Densities of the two most numerous species, the potamidid mud-whelk Terebralia sulcata and the Cerithidea-like cerithiid mud-creeper Cerithium coralium, are inversely correlated, although the species occurred together in 42% of quadrat samples. Within and beyond the normal range of field densities of each species (C. coralium mean 153 m−2; T. sulcata mean 75 m−2) there was no evidence of intraspecific depression of feeding rate, as assessed by the production of faecal pellets, although this was significantly reduced in the occasional very high density aggregations of C. coralium (>1100 m−2). The presence of the larger T. sulcata did appear to have a strong inhibitory effect on feeding in C. coralium; the converse, however, could not be demonstrated. Abundances of Terebralia palustris and C. coralium were also inversely correlated where the two co-occurred.

The mangrove intertidal zone is characterised by plenty floral and faunal diversity. The mangroves provide important habitat for a wide range of species like diverse communities of benthic organisms and function as nursery habitats for different types of crab, prawn and fish species and support offshore fish populations and fisheries. To assess the occurrence, spatial distribution and species composition of macro fauna in a mangrove area, core samples were taken along with transect in Portblair bay, South Andaman Islands. Three sites were taken; each study area was divided into three zones viz. Proximal, middle and distal zones, which were analyzed according to the floral composition. The highest value was observed at Barmanallah (2061 no.m-2), followed by Carbyn’s Cove (1710 no.m-2) and the lowest value was noticed at Manjery (882 no.m-2). Terebralia palustris, Cerithidea sp., Periopthalmus sp., Uca sp., Balanus sp. and Polychaetes were dominated in order. Some locations were found to support a high diversity of organisms across habitats, while other locations had high densities of a few species only.

The distribution of conch shell contained in clastic sediments in the mangrove swamps in the Funaura Bay, Iriomote Island, Okinawa Prefecture was studied. The sediments in the mangrove swamp are mainly composed of up to 90% sands. The sand clasts are inferred to be derived from the sandstone of Miocene Yaeyama Group. The conch shells are richer in the muddy fraction than the sandy fraction. Many Terebralia palustris inhabit the mangrove swamp. However few dead shells were also observed in the sediments. Effect of selective transportation hermit crabs is considered to be the cause of this distribution.

The gastropod Terebralia palustris (Linnaeus) isone of the largest prosobranchs found in tropical intertidal habitats. Theadults form feeding aggregations and frequently dominate the surface of muddysubstrates, where they clearly destabilize the sediment surface. We tested thefollowing hypotheses: 1. The gastropod has negative effects on the density ofinfaunal animals because of potential food competition and/or surface sedimentdisturbance. 2. The disturbance exerted by T. palustrisresults in more variable infaunal assemblages, especially where intensity ofdisturbance is high. To address these hypotheses gastropods were eitherenclosedor excluded from experimental cages, which were randomly assigned to blocks asfar as 300 m apart on an intertidal mudflat in East Africa. Afternine weeks of enclosure the gastropod at high densities clearly affected themeiofauna assemblages. Several meiofauna groups were found in significantlyreduced densities in the presence of the gastropod compared with control cageswithout the gastropods, supporting our primary hypothesis. In cages withoutT. palustris a cyanobacterial carpet developed while thiswas not evident in enclosure cages. T. palustris had nosignificant impact on the macrofauna assemblage. In support of our secondhypothesis, multidimensional scaling ordination (MDS) suggested that there wasan increased variability of meiofauna within cages with high density ofT. palustris.

In a mangrove tidal flat of Iriomote Island, Okinawa, an experiment on utilization of empty gastropod shells by hermit crabs was carried out. One hundred twenty-seven gastropod shells of Terebralia palustris were left at the mangrove tidal flat in the Funaura Bay of the Iriomote Island. After 48 hours, these shells were re-collected and shell size and distance from an experimental point were measured. Thirty-five shells were utilized by hermit crabs. Sixty shells were not used and left as before. Most of the shells used by the hermit crabs were collected at the distance of less than 10m from the experimental point. The most moved shells by the hermit crab were too far distance of 120m from the experimental point. The small-sized shells used by hermit crabs were collected near the experimental point. But, the shells collected at a distant from the experimental point were only large ones. In the mangrove swamp, dead gastropod shells were used by the hermit crabs immediately after death and they moved the shells to a long distance on a short time.