Corbicula Fluminea Research Articles

Reduction in mercury bioavailability to Asian clams (Corbicula fluminea) and changes in bacterial communities in sediments with activated carbon amendment

Activated carbon (AC) amendment is considered as one of the alternatives for managing and remediating mercury (Hg) contaminated sediments because of its high sorptive capacity and potential to immobilize the contaminant. For this study, the underlying mechanisms that control the reduction of Hg bioavailability in AC-amended estuarine sediments were investigated in box microcosm set-ups with 28-day Asian clam bioassay experiments. The application of diffusive gradients in thin film technique (DGT) revealed that the total mercury and methylmercury levels in sediment pore water decreased by 60%–75% in 1%–3% AC-amended sediments. This decrease subsequently led to a linear reduction in the Hg body burden in Asian clams, even at 1% sorbent mixing. These observations implied that AC amendment reduced the net flux of Hg into the pore water and overlying water, resulting in reduced Hg bioaccumulation in benthic organisms. The addition of AC to sediment also led to reduced dissolved organic carbon and several biogeochemical indicators (HS−, Mn, and Fe) in the pore water. Furthermore, the 16 S rRNA gene amplicon sequencing analysis revealed noticeable alterations in the microbial communities after AC amendment. The predominant phylum was Firmicutes in control sediment, Bacteroidetes in 1% AC-amended sediment, and Proteobacteria in both 2% and 3% AC-amended sediment samples. The genera-level analysis showed that the relative abundance of the Hg-methylators decreased as the level of AC amendment increased. These observations suggested that AC amendment decreased Hg bioavailability not only by physicochemical sorption but also by changing geochemical species and shifting the microbial community composition.

First Record of the Invasive Mussel Mytella strigata (Mollusca: Bivalvia: Mytilidae) in Panguil Bay, Southern Philippines

Here, we report the first record of the invasive mussel species Mytella strigata Hanley, 1843 in Panguil Bay, southern Philippines confirmed through its conchological features. Mussels appeared in dense mats attached to rocks, wood, and substrate in the intertidal region in the innermost portion of the bay. Locals first noticed the species in late 2018, which, according to them, adversely affected their catches of mangrove crabs Scylla spp. and the Asian hard clam Meretrix meretrix Linnaeus, 1758. There is a need to ascertain the distribution of the species within the bay, investigate socio-ecological and economic impacts, and formulate monitoring, surveillance, and impact mitigation measures.

Dynamic Regulation of Ions and Amino Acids in Adult Asian Hard Clams Meretrix lusoria Upon Hyperosmotic Salinity

The dynamic regulation of ions and amino acids in the gills and mantle of the Asian hard clam, Meretrix lusoria, following the exposure to a hyperosmotic environment was hitherto unclear. The present study revealed that the osmolality as well as the Na+ and Cl– concentrations in the hemolymph were significantly increased 3 h after transferring the clams from an environment with the salinity of their natural habitat (brackish water; BW; 20‰) to one with hyperosmotic salinity (seawater; 35‰). In addition, we found that the specific activities of Na+/K+-ATPase, a key enzyme that plays a significant role in cell osmoregulation, in the gills and mantle of clams were significantly increased at 72 and 12 h post-transfer, respectively, during acclimation to hyperosmotic salinity. Similarly, the contents of free amino acids (FAAs) such as taurine, alanine, and glycine were significantly elevated during hyperosmotic salinity acclimation. Previous research indicates that taurine is the most abundant FAA in the gills and mantles of Asian hard clams and that the taurine transporter (TAUT) plays an important role in taurine accumulation. The present study showed that TAUT mRNA and protein expression were significantly and transiently increased in the mantle of Asian hard clams following exposure to seawater; although the expression of TAUT mRNA in the gills of Asian hard clams was also transiently stimulated by exposure to hyperosmotic salinity, the relative TAUT protein abundance decreased only at later stages. Accordingly, the findings of this study improve our understanding of the dynamic processes of ion and amino acid regulation in the peripheral tissues of bivalves under hyperosmotic stress.

Heavy Metal Determination of Bivalves in Cagayan Valley, Philippines

Level of heavy metals like Cadmium (Cd) and Lead (Pb) in bivalves has been intensively studied during recent years as these hazardous substances could be accumulated in the biota and has been a hot issue in marine environmental studies. By consuming the shellfish, risk of bivalve related diseases may increase. And this shellfish poisoning is a concern to public health. This research study aims to determine if the Bivalves in Cagayan Valley, Philippines is safe to consume. The Freshwater clam (Corbicula fluminea) and the Marine mussel (Mytilus edulis) in Cagayan Valley, Philippines was collected for this study. The byssus and shells were removed, leaving only soft tissues to be used for the analysis and they were categorized into two. Graphite Furnace- Atomic Absorption Spectrophotometer (GFAAS) was used to determine the concentrations of Cadmium (Cd) and Lead (Pb). The results showed that the Freshwater bivalves Corbicula fluminea has a concentration 0.006 μg/g of Lead (Pb) and a concentration 0.016 μg/g. of Cadmium (Cd) while for Marine bivalves Mytilus edulis, the concentration of Pb was 0.011 μg/g and the concentration of Cd levels was 0.015 μg/g. The test results showed that the heavy metals, lead, and cadmium, were at low levels when referred to guidelines on heavy metals for food safety by different countries, particularly Malaysia. Thus, the results that were found were quite lower and there are no health risks to the people when consuming these bivalves collected from the province of Cagayan. Based on the results of the study conducted, the researchers recommend using different bivalve species to know the levels of heavy metals on bivalve species, investigate lead and cadmium heavy metals concentrations of one species collected in different areas/locations in Cagayan Valley and investigate the lead and cadmium heavy metal concentration of different bivalves in a regular basis i.e., monthly, or quarterly for at least 1 year.

Homogenization of Macroinvertebrate Assemblages and Asiatic Clam Corbicula fluminea Invasion in a River of the Arid Patagonian Plateau, Argentina

Fil: Labaut, Yeny. Universidad Nacional de Rio Negro, Instituto de Investigacion en Paleobiologia y Geologia. Rio Negro, Argentina.

Homogenization of Macroinvertebrate Assemblages and Asiatic Clam Corbicula fluminea Invasion in a River of the Arid Patagonian Plateau, Argentina

The invasion of the Asiatic clamCorbicula flumineain South America has already reached Patagonia. Despite the well-known direct and indirect impacts that this species exerts on fresh-water ecosystems, particularly on benthic communities, few studies have been undertaken on its effect on the composition and structure of aquatic macroinvertebrate assemblages. This study evaluated the effects of the invasion of the Asiatic clamC. flumineaon the aquatic macroinvertebrate assemblages of the Limay River, one of the most important rivers of the arid plateau of Argentinian Patagonia. As this river is currently in the process of being invaded, it was possible to compare invaded and non-invaded sites. Invaded sites displayed a certain homogenization of their constituent species and functional composition. Non-metric multidimensional scaling, similarity analysis and similarity percentages showed negative or positive influence of the presence of this species on the abundance of some taxa, due to competition for resources in this low-productivity Patagonian ecosystem. The deposition of the faeces and pseudo-faeces ofC. flumineaenriches the organic content of the sediments. However, its pedal feeding can function as a competitive strategy: by consuming its own deposited organic matter when food is scarce, the amount available to other macroinvertebrates is reduced. This paper is the first contribution on the impact of this invasion on northern Patagonia’s aquatic macroinvertebrate assemblages.

Are Fragrance Encapsulates Taken Up by Aquatic and Terrestrial Invertebrate Species?

The uptake potential of fragrance encapsulates by aquatic or terrestrial organisms was investigated. Because of their size of <5 mm and their polymeric nature, fragrance encapsulates fall under the Joint Group of Experts on the Scientific Aspects of Marine Environmental Protection definition of microplastics. After use, fragrance encapsulates enter the sewer system and reach the sewage treatment plant (STP), where >90% of them are likely to be removed by sorption to the sludge. When the STP-generated sludge is used as fertilizer for agricultural soils, this may lead to potential exposure of terrestrial invertebrates to fragrance encapsulates, especially those feeding on particles of a similar size as the fragrance encapsulates. Two aquatic (Corbicula fluminea [water exposure] and Hyalella azteca [water and dietary exposure]) and one terrestrial invertebrate (Eisenia andrei [soil exposure]) species were exposed to 50 mg/L (or mg/kg) double fluorescence-labeled fragrance encapsulates (diameter 5-50 µm). The results showed that fragrance encapsulates are available to aquatic and terrestrial invertebrates but that species-specific differences regarding the ability to ingest fragrance encapsulates may exist. The benthic grazer H. azteca showed no ingestion of fragrance encapsulates, whereas the capsules were readily ingested and egested by the unselective freshwater filter feeder C. fluminea as well as the terrestrial decomposer E. andrei. No signs of bioaccumulation of fragrance encapsulates were indicated by microscopic assessment. Environ Toxicol Chem 2022;41:931-943. © 2021 The Authors. Environmental Toxicology and Chemistry published by Wiley Periodicals LLC on behalf of SETAC.

Recent advances in environmental DNA‐based biodiversity assessment and conservation

Recent advances in environmental DNA‐based biodiversity assessment and conservation

Effect of a Novel Microwave-Assisted Induction Heating (MAIH) Technology on the Quality of Prepackaged Asian Hard Clam (Meretrix lusoria).

The microwave-assisted induction heating (MAIH) method—an emerging thermal technique—was studied to heat the prepackaged raw hard clam (Meretrix lusoria). The cooking effects on microbial and physiochemical qualities of clam were investigated. After the heating of the clam meat samples, the aerobic plate count (APC), psychrotrophic bacteria count (PBC), and total volatile basic nitrogen (TVBN) levels decreased with increasing heating time, but the shucking ratio, area shrinkage, and texture (hardness, cohesiveness, and chewiness) increased. In addition, the L* (lightness) and W (whiteness) of the clam meat samples increased significantly at the beginning of the heating period, whereas they decreased significantly with extended heating time. However, a* (redness) had the opposite trend. This study found that when clams were heated for more than 120 s at 130 °C or 150 s at 90 °C, they displayed obvious shrinking and a yellow-brown appearance, indicating that they are overcooked. After heating by MAIH for at least 110 s at 130 °C or 130 s at 90 °C, the samples were cooked well and gains a completely shucking, along with no microbial count detected. Therefore, the results indicated that the optimum heating conditions for prepackaged hard clams subjected to an MAIH machine were 130 °C for 110 s or 90 °C for 130 s.

Dietary composition of young sturgeons (Acipenseridae) from the Bulgarian section of the Danube River

ABSTRACT All sturgeon species currently living in the Danube River are either critically endangered or at the edge of extinction. Sturgeons are mainly benthic feeders, with a diet of molluscs, crustaceans, and small fishes. During the last two decades, we have seen a significant change in the species composition of benthic invertebrates in the Danube River as a result of anthropogenic impacts – hydrological and habitat modifications, introduction of alien and invasive species. The aim of this study was to investigate the food composition and the importance of different prey taxa, and to describe the feeding strategies of young sturgeons along the Bulgarian section of the Danube River. From June to August 2019, the stomach contents of 61 fish specimens from the species Acipenser stellatus, A. ruthenus, A. gueldenstaedtii were collected using gastric lavage. It was found that Obesogammarus obesus (Amphipoda) prevails in the diet of young of the year (YOY) A. stellatus and A. gueldenstaedtii, while Corbicula fluminea (Bivalvia) was the main food item of A. ruthenus. Chironomidae larvae also had high occurrences in the diet of all sturgeon species. For the YOY specimens up to 35 cm total length, nearly 94% of prey items belonged to O. obesus and diet overlap was observed. Improved knowledge about the diet of the young sturgeons could lead to the determination of the species’ major feeding habitats in the Danube River, providing crucial information for their protection and restoration.

Malacological news from the Czech and Slovak Republics in 2020

This paper presents important faunistic records including location data with all details conducted in the Czech and Slovak Republics during 2020. Four new non-native species, Arion intermedius, Ambigolimax valentianus, Clathrocaspia knipowitschii and Krynickillus melanocephalus, were recorded outdoors in Slovakia. Radix lagotis was genetically confirmed for the first time from several sites in the Czech Republic and Slovakia. Corbicula fluminea, recorded in Moravia for the first time in 2018, was found in another river, ca 50 km far from the first occurrence. Cepaea nemoralis, recorded in Slovakia for the first time in 2015, seems to have started spreading. New sites of Cornu aspersum were noticed in Prague and Bratislava; for the first time it was also found in Brno. There are also new records of several endangered species, e.g. Vertigo moulinsiana, Pisidium hibernicum, P. globulare, and Pseudanodonta complanata, presented.

A Biological Analysis on the Invasiveness of the Corbicula Fluminea

Corbicula fluminea is an invasive species that has been observed to outcompete the native clams at the American River located near Sacramento in the Central Valley in California. We hypothesized that C. Fluminea has advantages exhibited physically including utilization of filter-feeding methods and relative spacing of its cirri as compared to the native American River clams. To investigate what makes the species so successful, we tested C. Fluminea versus the native clams in algal and E.coli environments to predict the relative advantage of a filter feeder. In addition, we used computer programs to digitally analyze the spacing between the actual cirri, which help bivalves capture food particles, of the two species. The findings pointed towards C. Fluminea’s inherent advantage in both physical and genetic traits over the native clams species which allowed it to flourish and successfully invade the American River ecosystem. However, the species’ genetic findings are found through DNA analysis.

Geochemical behavior and fractionation characteristics of rare earth elements (REEs) in riverine water profiles and sentinel Clam (Corbicula fluminea) across watershed scales: Insights for REEs monitoring

The increasing global demand for rare earth elements (REEs) has led to their recognition as emerging contaminants; however, the effect that biota have on the cycling of these elements at the watershed scale is not currently well understood. In this study, water samples and field freshwater clams Corbicula fluminea were concurrently collected along watershed gradients, and concentration profiles of 14 naturally occurring REEs were measured in operationally defined water fractions and soft tissues of the freshwater clams. Moreover, Post Archean Australian Shale (PAAS) normalized REE patterns, fractionation indices, and anomalous values were determined to further extract characteristic features. As a result, both the water and biological samples had variable REE compositions, with higher concentrations of light REEs (LREEs) than middle REEs (MREEs) and heavy REEs (HREEs), while decreasing concentrations were generally observed as filter pore size decreased, implying that large colloidal and particulate fractions were important carriers of REEs. The spatial distribution patterns of REEs revealed a clear site effect among profiles, with variability more pronounced among watersheds and with peaks in sites from a small watershed near the hotspots of the mining area, and then exhibited a decreasing trend with distance from there. Meanwhile, significant bioaccumulation of REEs was observed potentially reflecting different degrees of contamination gradients among the watersheds. The PAAS-normalized distribution patterns tended to be slightly enriched in MREEs, producing a peculiar “roof-shaped” feature and characteristic fractionation. Remarkably, bio-concentration factors (BCFs) highlighted the importance of large colloidal and particulate phases in assessing biologically available REEs for filter-feeding species. Collectively, our study strongly favored that accumulation patterns and fractionation characteristics of REEs in C. fluminea can serve as a reliable indicator of geochemical behavior, providing a promising biomonitoring tool to quantitatively denote different degrees of REE contamination and assess possible impacts in mining watersheds.

Analysis of persistent organochlorine pesticides in shellfish and their risk assessment from aquafarms in Taiwan

In Taiwan, freshwater clams (Corbicula fluminea) and hard clams (Meretrix lusoria) are the most frequently raised shellfish in land-based pond aquaculture, but research on the accumulation of organochlorine pesticides (OCPs) in these shellfish is limited. We detected the levels of 14 OCPs in 62 shellfish from Taiwanese aquafarms by performing gas chromatography–tandem mass spectrometry. OCP residues were detected in 4.84% of the samples including readings of 0.04 mg/kg chlordane (in a freshwater clam), 0.03 mg/g p,p′-DDE (in a freshwater clam), and 0.02 mg/g p,p′-DDE (in a hard clam). However, the associated estimated daily intake values were less than the acceptable daily intake levels of chlordane and p,p′-DDE Therefore, the consumption of these shellfish presents no immediate health risks. Our findings contribute to food safety and serve as a reference for OCP screenings for aquatic shellfish.

Assessment of health risk on metal accumulation from consumption of Corbicula fluminea

Indicators of environmental quality encompass a number of environmental aspects such as water, soil and biotic life. As an example, the fundamental human needs is access to clean food sources. Nowadays, metals pollution has become a great concern as it could lead to a bad effect on a human’s health. In this study, heavy metals concentration in Corbicula fluminea is a clam that is frequently consumed by the local people in the state of Kelantan. In this study, metal concentration in Corbicula fluminea were determined and the possible human health effects were evaluated by using the Target Hazard Quotients (THQ. Five heavy metals were determined which are cadmium, arsenic, lead, copper, and zinc. The samples were collected from Tumpat, Kelantan whereby the study area was surrounded by agricultural activities and housing settlement. The sample went through a wet digestion process before being analysed by the Inductively Coupled Plasma-Mass Spectrometry (ICP-MS). The limit of heavy metals concentrations in aquatic species for consumption has been set for human health by Food and Agriculture Organization (FAO). Accumulation of heavy metals in the species were found to be high for cadmium. Furthermore, in risk and safety assessment, both arsenic and lead had very low level of metal concentration in the species. Based on the result obtained, cadmium exceeded the permissible limit set by the FAO, whereas, the calculated THQ was below one, which indicated means there was a least chance of carcinogenic effects to human’s health.

Distribución y dinámica poblacional de la almeja asiática Corbicula fluminea (Bivalvia, Corbiculidae) en ríos de Uruguay

The Asian clam (Corbicula fluminea) is a bivalve native to southeast Asia, introduced into the River Plate Basin to the end of the sixties. Since then, it has invaded a large number of watercourses in Brazil and Argentina, until reaching Venezuela and Colombia; its current distribution in Uruguay is poorly known. In this paper, we analyze the spatial distribution and population characteristics of C. fluminea in the basins of the South-Central and Eastern regions of Uruguay, in relation to abiotic variables. Sampling was conducted during one year in a bimonthly basis, and abundance, growth and mortality were estimated in five sites in the Santa Lucia river basin. The incidence of the Asian clam in the region was 50%. The probability of occurrence and abundance increased with the percentage of sand in the sediment and decreased with that of gravel. Slow growth rates, high body sizes and low mortalities were observed in fine sediments (sands and silts), following opposite trends in coarse sediment (gravels). Growth and mortality parameters were not correlated with density, suggesting that this population would be primarily regulated by environmental factors. C. fluminea could continue its expansion in Uruguay, invading sandy sectors of watercourses with low percentages of gravel and silt.

Specialized Feeding Patterns and Marine Resource Use by Nonnative Catfishes in a Coastal River Ecosystem Revealed by Dietary and Stable Isotopic Analyses

AbstractTwo large predatory catfishes, the Flathead CatfishPylodictis olivarisand Blue CatfishIctalurus furcatus, have been introduced into multiple U.S. Atlantic slope drainages in recent decades, with concomitant reductions in native fish abundance and changes in faunal community composition. Here, we report on a study of the trophic ecology of sympatric Flathead Catfish and Blue Catfish in the lower Cape Fear River, North Carolina, to estimate trophic positions and identify possible impacts on marine and estuarine prey resources. We applied both dietary and stable isotope analysis to quantify species‐specific foraging patterns, as well as the extent of variation among tributaries, seasonal periods, and ontogeny. Both catfish species displayed limited dietary breadth and specialized feeding patterns focused on prey resources within a restricted range of trophic levels. Dietary overlap between Blue Catfish and Flathead Catfish was low, and the species were separated by more than one trophic position. Flathead Catfish relied heavily on fish prey throughout ontogeny, with macroinvertebrates (crustaceans) as a consistent secondary prey resource, and showed increased reliance on potential anadromous prey resources at the largest sizes. Blue Catfish diets were dominated by the invasive Asian clamCorbicula fluminea, with contributions from fish prey only increasing for the largest individuals. Catfish trophic ecology varied among tributaries, and to a greater extent for Flathead Catfish, in terms of both the fish fauna eaten and the relative contribution of different invertebrate prey. Isotopic signatures for Flathead Catfish aligned with stomach contents to indicate a greater contribution of marine prey resources, including anadromous fishes, in the main‐stem Cape Fear River compared with the Black and Northeast Cape Fear rivers. Our findings indicate that the predatory impacts of catfishes introduced to coastal river ecosystems will differ considerably between catfish species and may also vary within systems across fine spatial scales.

An experimental evaluation of the efficacy of imaging flow cytometry (FlowCam) for detecting invasive Dreissened and Corbiculid bivalve veligers

Hassett W, Zimmerman J, Rollwagen-Bollens G, Bollens SM, Counihan TD. 2021. An experimental evaluation of the efficacy of imaging flow cytometry (FlowCam) for detecting invasive Dreissened and Corbiculid bivalve veligers. Lake Reserv Manage. 37:406–417. Zebra (Dreissena polymorpha) and quagga (D. bugensis) mussels, first introduced from central Asia into the Great Lakes of North America in the late 1980s, have crossed the continental divide and more recently spread across western North America. At the same time, several new technologies have been developed for the early detection of dreissenids, including the FlowCam, a digital imaging-in-flow instrument, intended to detect dreissenid planktonic larvae (veligers). However, the efficacy of this technology has rarely been tested. We experimentally evaluated the FlowCam’s ability to capture identifiable images of quagga mussel veligers under 2 different types of conditions: (i) deionized water, and (ii) Columbia River Basin water (CRBW), including natural sediment and native plankton. We further evaluated the FlowCam’s ability to distinguish between dreissenid veligers and corbiculid veligers (Asian clam, Corbicula fluminea). We interpret our results to indicate that the FlowCam can consistently detect dreissenid veligers across a range of veliger densities. Moreover, the presence of other plankton and detritus only slightly affected dreissenid detection by the FlowCam. However, the orientation of individual bivalve veligers as they were imaged by the FlowCam precluded specific identification of a substantial proportion (24.8%) of veligers as either dreissenid or corbiculid. We suggest that the FlowCam is an important detection tool best utilized as part of a multifaceted approach, including traditional microscopy and possibly environmental DNA.

An Investigative Study into the C. flumenia and its Interactions with its Surrounding Ecosystem

his research focused on the physical characteristics of Corbicula flumenia, an invasive species of clam found in the American River, and how these characteristics give it a possible survival advantage over native clam species of the river. Clams were collected from the American River and dissected, while river water and soil samples were also collected. The water and soil were analyzed for levels of coliforms such as E. coli, since this could be a food source that gives the Asian Clam an advantage over native species. The Asian clams were analyzed for their feeding efficiency of E. coli compared to algae and also compared for anatomical differences to the native species by measuring cirri size, which could increase feeding rates within these clams, giving them a competitive edge over their native competitors. It was found that there was much E. coli in the water and soil, but no significant correlation was found between clam cirri size and feeding rate. The Asian clam’s DNA and protein expression was analyzed for genetic mutations that contribute to the species’ invasive advantage.

Optimization of enzymatic protein hydrolysis conditions of Asiatic hard clam (Meretrix meretrix)

This study was aimed to optimise the Alcalase® enzymatic hydrolysis extraction of Asiatic hard clam (AHC) (Meretrix meretrix) protein hydrolysate in terms of hydrolysis time, hydrolysis temperature, hydrolysis pH, and concentration of enzyme. Protein hydrolysate produced from AHC (M. meretrix) meat was used to determine the optimum hydrolysis conditions. Hydrolysis of AHC meat was optimised using the Central Composite Design Response Surface Methodology (RSM) (CCD). The relationship between four parameters such as temperature (45 – 65°C), enzyme to substrate concentration (1 – 2%), hydrolysis time (60 – 180 mins), and pH (7.5 – 9.5) to the degree of hydrolysis was investigated. The optimum conditions for enzymatic hydrolysis of AHC meat to achieve the maximum degree of hydrolysis (DH) were observed at 65°C, enzyme to substrate concentration of 1%, hydrolysis time of 60 mins, and pH 7.5. The enzymatic protein hydrolysis of AHC meat was predicted using a two factors interaction (2FI) model. Under these optimum conditions, DH's predicted value was 97.41%, which was close to the experimental value (97.89%). The freeze-dried protein hydrolysate powder was characterized concerning the proximate composition. Proximate analysis revealed that the AHC meat contains 7.92±1.76% of moisture, 2.23±0.89% of crude fat, 1.98±0.82 of ash, and 10.53±0.04% of crude protein. While the Asiatic hard clam protein hydrolysate (AHCPH) composed 9.12±0.02% of moisture, 0.80±0.29% of crude fat, and 27.76±0.10% of ash. The protein hydrolysate produced also contained high protein content (50.09±0.88%) and may serve as a good protein source.