The pinnotherid crab, Pinnothera obesa Dana, 1852, was originally described on the basis of material from Fiji, but its taxonomic status has long been obscure because the original description and figures are too brief and schematic by modern standards and the types are also lost. Examination of newly collected material from Fiji revealed the presence of two intertidal pinnotherid species assignable to the genus Arcotheres Manning, 1993, one of which is herein identified with Dana's taxon. A neotype is designated for Arcotheres obesus n. comb. in the interest of nomenclatural stability, and a detailed redescription is given. Arcotheres obesus is morphologically similar to A. exiguus (Bürger, 1895) and A. rotundatus (Bürger, 1895), and differentiating characters are discussed. The species is also reported from Peninsular Malaysia. The second species is new to science, here described as Arcotheres ocularius, and is most similar to A. palaensis (Bürger, 1895) and A. arcophilus (Bürger, 1895). The new species is also recorded from Lombok, Indonesia. Arcotheres obesus and A. ocularius n. sp. are associated with bivalve mollusks of the genera Gafrarium spp. (Veneridae) and Anadara spp. (Arcidae), respectively.
This study aimed to determine the physicochemical properties of undulated surf clam (Paphia undulata) hydrolysate as affected by the degree of hydrolysis (DH). Three levels of DH of undulated surf clam hydrolysate were prepared which were DH 36.57% (without any enzymatic hydrolysis), DH 58.25% (0.5% Alcalase®; 5 min; pH 7.5; 60ºC) and DH 91.26% (1% Alcalase®; 30 min; pH 7.5; 60ºC). After protein hydrolysis, the undulated surf clam hydrolysates were centrifuged, and their supernatants were freeze-dried. This study found that the protein hydrolysate with lower DH (DH 36.57%) gave lower protein content and higher ash and fat contents compared to other samples (DH 58.25% and DH 91.26%). However, the carbohydrate content is similar in all samples (16.56-20.04%). This study also found that foaming properties (29.43-67.50%), emulsifying capacity (11.94-110.52%) and peptide solubility (57.61-94.08%) were affected by the DH. As DH increased, the emulsifying capacity decreased, while peptide solubility increased. While the foaming capacity increased with increasing DH until it reached a maximum value and level off afterwards. For colour parameters, although there were differences between L*, a* and b* values for all three samples, a fluctuating pattern was noted with DH. DH also did not affect the water-holding and oil-holding capacity of undulated surf clam hydrolysate. This study shows that certain physicochemical properties of undulated surf clam hydrolysate can be tailored by adjusting the degree of hydrolysis.
A study of the reproductive cycle of the hard clam, Meretrix lyrata, was documented based on histological observation and Gonad Index (GI). Samples were taken from estuarine waters of the Buntal River in Sarawak, Malaysia. The gonad of M. lyrata started to develop in September 2013. Gametogenesis continued to develop until the maturation and spawning stage from February to April 2014. The GI pattern for a one-year cycle showed a significant correlation with chlorophyll a. The corresponding GI with chlorophyll a suggested that the development of the reproductive cycle of M. lyrata required a high amount of food to increase gametogenesis.
Heavy metal accumulation and depuration may alter the effectiveness of Meretrix meretrix as a biomonitoring organism for water quality assessment. Therefore, this study was conducted to evaluate the effects of heavy metal accumulation and depuration on M. meretrix, by immersing it in Copper (Cu), Zinc (Zn), and Lead (Pb)
solutions under laboratory conditions. The results showed that M. meretrix is able to accumulate Cu, Zn, and Pb at the rate of 0.99, 21.80, and 0.57 μg/g per day, respectively, and depurates at the rate of 0.42, 23.55, and 1.01 μg/g per day, respectively. These results indicate that M. meretrix could be effectively used as a biomonitoring organism for Cu because the accumulation rate is significantly (p ≤ 0.05) higher than the depuration rate. However, this was not the case for Zn because the accumulation rate was almost similar to the depuration rate, while for Pb, accumulation or depuration did not occur in M. meretrix.
Land reclamation in Penang began two decades ago and is still rampant with
large reclamation projects planned to be executed in the near future. The present study
provides the first information on effects of land reclamation in Penang towards the coastal
macroinvertebrates. This study assessed the abundance, diversity, and evenness of
coastal invertebrates assumed to be the foremost affected when land is reclaimed. Three
kinds of areas were focused on: reclaimed, unclaimed (adjacent to reclaimed), and
undisturbed. A total of 53 species of macroinvertebrates from 10 classes (Gastropoda,
Bivalvia, Polychaeta, Malacostraca, Maxillopoda, Echinoidea, Polyplacophora,
Branchiopoda, Scaphopoda, and Holothuroidea) were sampled. Reclaimed areas were
moderately rich in species averaging 11 species compared to 7 species in adjacent and
14 in undisturbed areas. Species richness was the highest in Teluk Aling (an undisturbed
area) with 22 species, and was the lowest in Gurney Drive (an adjacent area) with 2
species. The average species diversity and evenness on reclaimed land was the lowest
with values of 1.9974 and 0.5787, respectively. The diversity was higher by 5.07% in
adjacent areas and by 22.92% in undisturbed areas compared to reclaimed areas.
Species evenness was 29.75% higher in unreclaimed areas and 17.87% higher in
undisturbed areas compared to reclaimed areas. Land reclamation reduces species
diversity and evenness, and to a lesser extent, species richness.
Red seaweed Gracilaria, one of the largest genus in Division Rhodophyta inhabits Sarawak coastal water. This study was designed to identify the species of Gracilaria using morphological approach and to assess selected water quality parameters in Gracilaria habitats. Three field samplings were carried out in Santubong and Asajaya, Sarawak from November 2013 to December 2014. Overall, three species were identified namely Gracilaria changii, G. blodgettii and G. coronopifolia, attached to net of cage culture in Santubong and root of mangrove trees in Asajaya. In addition, three different taxa of aquatic macroinvertebrates (polychaete, small crab, bivalve) and single species of red seaweed (Acanthophora sp.) were observed in Gracilaria assemblages. An estimate of 37% to 40% of the upper part of the cage net in Santubong was covered by seaweeds and only 16% to 20% in Asajaya's mangrove. The study had provided better information on identification of Gracilaria and their habitat in Sarawak. Future work involving DNA barcoding of each species is in progress.
Benthic faunal communities are important components in the intertidal zones.
The diversity and abundance of the benthic communities are subjected to different natural
and anthropogenic disturbances. The study was conducted as one off sampling on 6th
November 2013 (1) to investigate the abundance and distribution of soft sediment
communities in relation to environmental variables and (2) investigate the changes of
population structure and diversity using spatial scales of 1 m, 10 m, and 100 m. Results
indicated a total of 110 individuals of macrobenthos consisting of 7 different groups
(Annelida, Bivalvia, Crustacea, Gastropoda, Nematoda, Nemertea, Polychaeta) and 4
different groups of meiobenthos (Copepoda, Nematoda, Ostracoda, Polychaeta)
consisting 920 individuals were recorded. Dissolved oxygen played the most significant
role in affecting the distribution of soft sediment communities while ammonia
concentrations only affected marcobenthic organisms. However, sediment grain size did
not show significant correlation (p>0.05) on soft sediment communities. Hence,
understanding how different properties of benthos respond to changes in environmental
variables is crucial in determining how the impacts on the sediment are tolerated by the
benthic organisms.
Species invasion is an important cause of global biodiversity decline and is often mediated by shifts in environmental conditions such as climate change. To investigate this relationship, a mechanistic Dynamic Energy Budget model (DEB) approach was used to predict how climate change may affect spread of the invasive mussel Mytilopsis sallei, by predicting variation in the total reproductive output of the mussel under different scenarios. To achieve this, the DEB model was forced with present-day satellite data of sea surface temperature (SST) and chlorophyll-a concentration (Chl-a), and SST under two warming RCP scenarios and decreasing current Chl-a levels, to predict future responses. Under both warming scenarios, the DEB model predicted the reproductive output of M. sallei would enhance range extension of the mussel, especially in regions south of the Yangtze River when future declines in Chl-a were reduced by less than 10%, whereas egg production was inhibited when Chl-a decreased by 20-30%. The decrease in SST in the Yangtze River may, however, be a natural barrier to the northward expansion of M. sallei, with colder temperatures resulting in a strong decrease in egg production. Although the invasion path of M. sallei may be inhibited northwards by the Yangtze River, larger geographic regions south of the Yangtze River run the risk of invasion, with subsequent negative impacts on aquaculture through competition for food with farmed bivalves and damaging aquaculture facilities. Using a DEB model approach to characterise the life history traits of M. sallei, therefore, revealed the importance of food availability and temperature on the reproductive output of this mussel and allowed evaluation of the invasion risk for specific regions. DEB is, therefore, a powerful predictive tool for risk management of already established invasive populations and to identify regions with a high potential invasion risk.
Freshwater mussels (Bivalvia, Unionida) fulfil important ecosystem functions and are one of the most threatened freshwater taxa globally. Knowledge of freshwater mussel diversity, distribution and ecology in Peninsular Malaysia is extremely poor, and the conservation status of half of the species presumed to occur in the region has yet to be assessed. We conducted the first comprehensive assessment of Peninsular Malaysia's freshwater mussels based on species presence/absence and environmental data collected from 155 sites spanning all major river catchments and diverse habitat types. Through an integrative morphological-molecular approach we recognised nine native and one widespread non-native species, i.e. Sinanodonta woodiana. Two species, i.e. Pilsbryoconcha compressa and Pseudodon cambodjensis, had not been previously recorded from Malaysia, which is likely a result of morphological misidentifications of historical records. Due to their restriction to single river catchments and declining distributions, Hyriopsis bialata, possibly endemic to Peninsular Malaysia, Ensidens ingallsianus, possibly already extinct in the peninsula, and Rectidens sumatrensis, particularly require conservation attention. Equally, the Pahang, the Perak and the north-western river catchments are of particular conservation value due to the presence of a globally unique freshwater mussel fauna. Statistical relationships of 15 water quality parameters and mussel presence/absence identified acidification and nutrient pollution (eutrophication) as the most important anthropogenic factors threatening freshwater mussel diversity in Peninsular Malaysia. These factors can be linked to atmospheric pollution, deforestation, oil-palm plantations and a lack of functioning waste water treatment, and could be mitigated by establishing riparian buffers and improving waste water treatment for rivers running through agricultural and residential land.
Global human population has increased dramatically over the past 50 years. As a result, marine fisheries and finfish aquaculture have become increasingly unsustainable, driving bivalve aquaculture to become an important food industry for the production of marine animal protein to support the growing market demand for animal protein. It is projected that the rate of bivalve aquaculture expansion will be greatly accelerated in the near future as the human population continues to increase. Although it is generally believed that unfed bivalve aquaculture has less impact on the environment than finfish aquaculture, the rapid expansion of bivalve aquaculture has raised concerns about its potential negative impact, especially on plankton and benthic community. Therefore, there is an urgent need to update the potential effects of bivalve aquaculture on plankton and benthic community. This article reviews the present state of knowledge on environmental issues related to bivalve aquaculture, and discusses potential mitigation measures for the environmental impacts induced by expansion of bivalve aquaculture. This review provides guidance for scientists and farm managers to clarify the current state of research and identify priority research needs for future bivalve aquaculture research. Therefore, specific management strategies can be formulated for the sustainable development and expansion of bivalve aquaculture.
Dissolved oxygen (DO) is an important parameter that affects the biology, physiology, and immunology of aquatic animals. In recent decades, DO levels in the global oceans have sharply decreased, partly due to an increase in atmospheric carbon dioxide, temperature, and anthropogenic nutrient loads. Although there have been many reports on the effects of hypoxia on the survival, growth, behavior, and immunity of bivalves, this information has not been well organized. Therefore, this article provides a comprehensive review of the effects of hypoxia on bivalves. In general, hypoxia negatively impacts the food consumption rate and assimilation efficiency, as well as increasing respiration rates in many bivalves. As a result, it reduces the energy allocation for bivalve growth, shell formation, and reproduction. In severe cases, prolonged exposure to hypoxia can result in mass mortality in bivalves. Moreover, hypoxia also has adverse effects on the immunity and response of bivalves to predators, including decreased burial depths, sensitivity to predators, impairment of byssus production, and negatively impacts on the integrity, strength, and composition of bivalve shells. The tolerance of bivalves to hypoxia largely depends on size and species, with larger bivalves being more susceptible to hypoxia and intertidal species being relatively more tolerant to hypoxia. The information in this article is very useful for elucidating the current research status of hypoxia on bivalves and determining future research directions.
1. Study of the structure and mode of life of Malleus regula provides the basis for consideration of the "hammer" species, M. malleus and M. albus.
2. M. regula occurs byssally attached, vertically disposed on rocky substrates associated with mud and is widely distributed in the tropical Indo-Pacific.
3. The distal two-thirds of the elongated shell is exclusively prismatic. By means of special pallial retractors the mantle lobes can be withdrawn within the nacreous region.
4. The massive opisthodetic ligament has a short secondary extension of fusion layer.
5. A promyal chamber on the right side proximal to the adductor increases water flow into the exhalant chamber.
6. The long filibranch ctenidia provide a vertically extended food-collecting surface.
7. The foot is concerned with planting of the massive byssus which emerges through a notch in the right valve but on the under ( i.e., dorsal) surface. There is also a unique and very long accessory foot, ventrally grooved, everywhere ciliated and in constant writhing activity due to blood pressure and intrinsic muscle. Moving freely throughout the lower mantle cavity it can only be concerned with cleansing.
8. Pseudofaeces are ejected from the distal tip of the mantle cavity.
9. M. malleus, the black hammer shell, occurs vertically embedded in coarse sand or sandy gravel. Byssus threads are attached to fragments within the substrate. The great anterior and posterior elongations of the hinge line (also exclusively prismatic) are separated by the byssal notch (now affecting both valves).
10. Shells are usually excessively irregular due to the great exposure to damage and the almost unlimited powers of rapid repair by the three pallial extensions.
11. M. albus, the white hammer shell, is stouter and inhabits muddy sand. During growth it loses the byssus with reduction of the foot and byssal retractors and closure of the byssal notch. The accessory foot is not affected. The animal becomes anchored in the substrate exclusively by the anterior and posterior extensions of the shell.
12. Description of the typically rounded Isognomon ephippium leads to that of the elongated I. isognomon which occupies precisely the same habitat as M. regula.
13. It lacks the pallial retractors, promyal chamber and accessory foot of Malleus, the nacreous region is more extended distally and the ligament is multivincular (the formation of which is discussed), producing some posterior, but never any anterior, extension of the hinge line.
14. A remarkably dense mixed bed of M. regula and I. isognomon in Darvel Bay, Sabah (Borneo), is described. Different spawning periods, by preventing competition during settlement, may account for this complete intermixing of sympatric species, which, however, are generalized herbivores where numbers are not limited by food supply.
15. From a basic epifaunal habit (Pteria, Isognomon, M. regula), members of the Pteriacea have become adapted for infaunal life within sponges (Vulsella, Crenatula) or within soft substrates ( M. malleus, M. alba and the Pinnidae).
16. There is final discussion about elongation in monomyarians, i.e., in the genus Malleus and in I. isognomon.
In this study, Hydrolysate from angelwing clam (Pholas orientalis) was produced at 0, 1, 2 and 3 hrs and E/S ratio of 0.5 and 3% using alcalase where the pH and temperature were kept constant at pH 8.5 and 60°C, respectively. The hydrolysates were analysed for antioxidant and functional properties such as solubility, emulsifying properties and water and oil holding capacity. Degree of hydrolysis (DH), yield, functional and antioxidant properties were influenced by the hydrolysis time and E/S ratio. Higher enzyme concentration (E/S 3%) and longer hydrolysis time increased the DH. Yield was higher at E/S 3% but reduced with hydrolysis time. Longer hydrolysis time produced more soluble hydrolysate and higher metal chelating activity but lower in emulsifying properties and DPPH activity. Higher enzyme concentration resulted in increase only in solubility and metal chelating activity. This study revealed that enzymatic hydrolysis using alcalase should be performed at shorter hydrolysis time using intermediate concentration of enzyme (E/S between 0.5 to 3%) in order to produce angelwing clam hydrolysate with collectively good functional and antioxidant properties
Vibrio parahaemolyticus is a foodborne bacterial pathogen that may cause gastroenteritis in humans through the consumption of seafood contaminated with this microorganism. The emergence of antimicrobial and multidrug-resistant bacteria is another serious public health threat worldwide. In this study, the prevalence and antibiotic susceptibility test of V. parahaemolyticus in blood clams, shrimps, surf clams, and squids were determined. The overall prevalence of V. parahaemolyticus in seafood was 85.71% (120/140), consisting of 91.43% (32/35) in blood clam, 88.57% (31/35) in shrimps, 82.86% (29/35) in surf clams, and 80% (28/35) in squids. The majority of V. parahaemolyticus isolates from the seafood samples were found to be susceptible to most antibiotics except ampicillin, cefazolin, and penicillin. The MAR indices of V. parahaemolyticus isolates ranged from 0.04 to 0.71 and about 90.83% of isolates were found resistant to more than one antibiotic. The high prevalence of V. parahaemolyticus in seafood and multidrug-resistant isolates detected in this study could pose a potential risk to human health and hence appropriate control methods should be in place to minimize the potential contamination and prevent the emergence of antibiotic resistance.
Condition Index (CI) was used to estimate the reproductive biology cycle of the hard clam Meretrix lyrata based on dry
body weight and shell weight. High CI value was observed due to the increase in the body weight of the hard clam that
corresponding to the maturity stage and early spawning. The CI value of M. lyrata from Buntal Village, Kuching, Sarawak
showed three highest peaks during the 12-month study on May and October 2013 and March 2014. The lowest CI values
were obtained in September and November 2013 and April 2014. Ammonia nitrogen was the only water parameter that
significantly correlated to the CI values. The CI application is important to estimate the maturity of hard clam gonad
to facilitate conservation activity through the hard clam harvesting out of the gonad maturation and spawning period.
Pengimejan tradisi mempunyai banyak kekurangan seperti mempunyai jangka hayat yang pendek serta bersaiz besar
kerana sifat pendafluornya tidak tahan lama atau berlakunya pelunturanfoto. Melalui kajian ini, nanohablur kadmium
sulfida dihasilkan dan berfungsi sebagai pengimejan titik kuantum yang sesuai dengan sifat optiknya yang pelbagai
mengikut saiz zarahnya. Sifat optik titik kuantum kadmium sulfida (TK CdS) boleh dipengaruhi oleh saiz dan juga
komposisi kimia TK seperti perubahan pH. Dalam kajian ini, sifat optik TK CdS dikaji terhadap perubahan nilai pH
dengan menghasilkan TK CdS melalui kaedah koloidal. Kadmium asetat dihidrat (C4
H6
CdO4
.2H2
O) dan natrium sulfida
(Na2
S) digunakan sebagai sebagai bahan pemula bagi menghasilkan TK CdS. Nilai pH diubah suai dengan menitiskan
natrium hidroksida (NaOH) ke dalam larutan TK CdS. Lima jenis larutan disediakan iaitu pada nilai pH5, pH7, pH8,
pH9 dan pH10. Masalah penggumpalan sering berlaku semasa proses sintesis CdS. Oleh itu, kajian ini menggunakan
asid tioglikolik (HSCH2
CO2
H) sebagai agen penstabil kepada TK CdS. Spektra keserapan UV memberi anjakan biru
apabila TK CdS pada pH alkali kerana saiz nanohablur mengecil. Hasil daripada spektroskopi pendarfluor mendapati
larutan yang mempunyai nilai pH8 memberi puncak yang tertinggi. Hal ini adalah kerana pada pH ini nanohablur
mampu berubah pada posisi yang tepat dan membentuk TK CdS pada kehabluran yang tinggi. Oleh itu, mekanisme ini
dapat membentuk perangkap lubang dan seterusnya eksiton terbentuk.
Harmful algal blooms (HABs) events have been increasingly reported in the country, not only of the frequency and severity of the events, but also involved more species than previously known. In this paper, a decadal review of HABs events in Malaysia is summarized. Bloom events caused by harmful dinoflagellate species including the shellfish poisoning events were highlighted. Paralytic shellfish poisoning (PSP) is no longer restricted to Sabah coasts and Pyrodnium bahamense. Bloom of Alexandrium minutum was reported for the first time in the Peninsula with six persons hospitalized including one casualty after consuming the contaminated benthic clams. Algal blooms that are associated with incidence of massive fish kills have been reported from both east and west coasts of the Peninsula in conjunction to finfish mariculture loses. The culprits of these bloom events have been identified as the dinoflagellates, Cochlodinium polykrikoides, Neoceratium furca, Prorocentrum minimum, Noctiluca scintillans and a raphidophyte, Chatonella ovata. In this paper, some of these HABs species were characterized morphologically and genetically, including their toxicity. Therefore, with the increase of coastal utilization and eutrophication, prevention, management and mitigation strategies, such as site selection, moving pens, clay spraying should be adopted to minimize the impact of these natural events.
Kajian kandungan logam berat Cd, Co, Cr, Ni, Pb, dan Zn telah dilakukan ke atas tumbuhan Arundina graminifolia daripada kawasan Lombong Pelepah Kanan, Kota Tinggi, Johor. Kandungan logam berat yang sama turut ditentukan ke atas substrata tanih di tempat di mana tumbuhan itu diambil. Kandungan logam berat dalam tiga bahagian tumbuhan iaitu akar, batang dan daun telah diekstrak secara penghadaman basah manakala kandungan logam berat tersedia dan resistan dalam tanih diekstrak dengan kaedah pengekstrakan berjujukan. Kandungan logam berat jumlah didapati dengan menjumlahkan logam berat tersedia dengan logam berat resistant. Kandungan logam berat di dalam larutan ekstrak tanih dan tumbuhan ditentukan menggunakan Spektrofotometer Serapan Atom Nyalaan. Kandungan logam berat Cd, Cr, Ni dan Pb adalah setara kandungannya dalam semua bahagian tumbuhan manakala kepekatan Co dan Zn adalah tiga hingga lima kali lebih tinggi berbanding tumbuhan kawalan. Bagi kandungan logam berat di dalam bahagian tumbuhan yang berbeza didapati kepekatan Cd adalah lebih tinggi dalam akar (2.03 mg/kg) diikuti oleh daun (1.67 mg/kg) dan batang (1.49 mg/kg). Kepekatan Co adalah lebih tinggi dalam daun (9.26 mg/kg) diikuti oleh akar (9.18 mg/kg) dan batang (6.94 mg/kg). Kepekatan Cr mengikut susunan menurun adalah akar (0.46 mg/kg) > daun (0.19 mg/kg) > batang (0.08 mg/kg). Kepekatan Ni adalah lebih tinggi dalam daun (2.78 mg/kg) diikuti oleh akar (2.71 mg/kg) dan batang (1.66 mg/kg). Kepekatan Pb mengikut susunan menurun adalah akar (10.34 mg/kg) > daun (4.18 mg/kg) > batang (3.75 mg/kg). Kepekatan Zn lebih tinggi dalam daun (44.03 mg/kg) diikuti oleh akar (32.30 mg/kg) dan batang (13.21 mg/kg). Kandungan logam berat jumlah dalam tanih adalah masing-masing 2.07-5.59 mg/kg, 8.72-39.93 mg/kg, 1.81-2.14 mg/kg, 2.66-6.87 mg/kg, 23.02-51.56 mg/kg and 0.64-2.61 mg/kg bagi Ni, Zn, Cd, Pb, Co dan Cr. Didapati bahawa kandungan fraksi tersedia dalam tanih adalah 21.9% bagi Ni, 15.3% bagi Zn, 49.9% bagi Cd, 19.3% bagi Pb, 45.7% bagi Co and 0% bagi Cr. Koefisien penyerapan biologi tumbuhan ke atas logam berat yang dikaji adalah rendah keculai bagi Zn yang nilainya lebih daripada 1. Tumbuhan ini tidak sesuai digunakan sebagai agen fitoremediasi untuk logam-logam di atas.
The first time report on the feeding ecology and food preference of mangrove horseshoe crab Carcinoscorpius rotundicauda (Latreille 1802) at their nesting grounds along the Pahang coast is given. Monthly sampling was carried out between March 2010 and February 2011 covering both monsoonal (March to October) and non-monsoonal (November to February) seasons. Major macrobenthic gut contents (bivalves, gastropods, crustaceans, polychaetes and miscellaneous food items including plant materials) were identified using microscopic examination. An electivity index (E1) was calculated for the frequent food items observed in the gut region of C. rotundicauda during monsoon and non-monsoon seasons. The EI was negative for crustaceans and positive for all the other food items including bivalves, gastropods, polychaetes and miscellaneous food items (which include insects, amphipods, Isopods, larval and juvenile stages of fishes, foraminifera and other Annelid worms). It is interesting to note that C. rotundicauda prefered less number of bivalves than polychaetes during non monsoon seasons but it was the reverse during monsoonal period. Male crabs intensely preyed on gastropods and female prefers polychaete worms during the peak mating/nesting season (June - August 2010). Seasonal variations in food composition showed that mollusks formed the main item especially gastropods. Unidentified organic matters in the gut content analysis of C. rotundicauda showed high preference towards plant materials. Gastro Somatic Index (GaSI) analysis showed that the feeding intensity of male crabs was higher during non-monsoon period while it was higher during monsoonal period in female crabs. In conclusion, the feeding ecology of mangrove horseshoe crabs were more similar to its closer and distant conspecifics. However, it was postulated that the higher preference of polychaete worms by the female C. rotundicauda during the peak mating season indicated its role in regulating the nesting behaviour.
Pengecaman senjata api semakin serius dan amat penting di dalam bidang penyiasatan jenayah khususnya untuk tempoh dua dekad ini. Dalam makalah ini, suatu sistem untuk pengecaman senjata api berasaskan tapak kelongsong peluru telah diperkenalkan. Tapak kelongsong peluru adalah satu daripada penunjuk yang amat penting dalam membantu menyelesaikan masalah pengecaman pistol. Peluru yang telah digunakan akan meninggalkan lebih daripada 30 ciri yang amat berharga pada tapak kelongsong bagi membantu pihak tertentu mengecam pistol yang telah diguna. Ciri-ciri tersebut sebagai suatu gabungan membentuk apa yang dikenali sebagai kesan cap jari bagi pistol. Lantaran itu, kajian ini adalah untuk mendapatkan fitur yang sesuai bagi pengecaman senjata api. Terlebih dahulu imej tapak kelongsong peluru ini telah ditemberengkan kepada tiga bahagian, membentuk tiga set imej yang berlainan. Imej-imej ini juga dilakukan prapemprosesan untuk membentuk tiga set imej lagi. Fitur-fitur seterusnya disaring daripada imej asal tapak kelongsong peluru dan imej yang telah melalui prapemprosesan. Dua puluh fitur yang berbeza secara signifikan telah diperoleh dan dikirakan untuk imej-imej asal dan yang telah dilakukan prapemprosesan. Kesemua pemprosesan telah dilakukan menggunakan pengaturcaraan MATLAB. Suatu skim berdasarkan analisis korelasi seterusnya telah diperkenalkan untuk pencarian fitur berdasarkan konsep meminimumkan lewahan data tetapi memastikan ciri-ciri unik tersimpan. Fitur-fitur yang berkorelasi tinggi akan digugurkan pasangannya dan hasilnya tinggal cuma tujuh fitur sahaja. Ketujuh-tujuh fitur ini telah diuji sebagai suatu vektor fitur untuk mengelaskan lima pistol daripada model yang sama menggunakan analisis diskriminan. Hasil pengelasan menunjukkan lebih 80% daripada imej-imej tapak kelongsong peluru itu telah dikelaskan dengan jayanya.