Anadara Kagoshimensis Research Articles

Pathogenic and genomic characterization of Ostreid herpesvirus 1 associated with mass mortalities of blood cockle (Anadara kagoshimensis)

Ostreid herpesvirus 1 (OsHV-1) is an infectious viral disease of bivalve mollusks with a wide geographic distribution across five continents. Since its initial identification in 1991, the disease has been identified as the cause of mortality in more than ten species of bivalve mollusks. The transmission of OsHV-1 is thought to be facilitated by water. In 2019 and 2021, mass mortalities of blood cockle (Anadara kagoshimensis) hatchery broodstock associated with OsHV-1 infection were reported. The presence of OsHV-1 DNA was confirmed in all hatchery samples with levels exceeding 106 copies per milligram of DNA. OsHV-1 was not detected in the wild populations from which the broodstock was collected, indicating that the virus was introduced into the hatchery with seawater from the open ocean. The results of the histopathological examination indicated that tissue lesions and associated hemocyte infiltration were most prevalent in the connective tissues of the digestive tract, mantle, gills and foot of the diseased A. kagoshimensis. In situ hybridization (ISH) signals of OsHV-1 DNA were frequently observed in infiltrated hemocytes, putative fibroblasts, and on occasion, in muscle cells with weak staining. Transmission electron microscopy analysis demonstrated the presence of herpes-like viral particles within the nucleus of infected cells. The genomes of the OsHV-1 variants from cases 2019 and 2021 were successfully resolved through direct high-throughput sequencing of infected tissues. A phylogenetic analysis of the complete genome sequences of 32 OsHV-1 variants revealed that the segregation of the virus was primarily structured by host species and geographic origin, with some exceptions. We propose that the sympatric distribution of different host species and the potential occurrence of cross-species transmission of OsHV-1 are responsible for the inconsistency between the phylogenetic segregation and their host species. This is the first report on the pathogenic and genomic characterization of OsHV-1 infecting A. kagoshimensis. The epidemiological and phylogenetic analyses offer new insights into the evolution of the virus and provide valuable information for the prevention and control of the disease.

Effect of hypoxia on amino acid content in haemolymph and protein hydrolysate of the bivalve mollusk Anadara kagoshimensis (Tokunaga, 1906)

Effect of hypoxia on amino acid content in haemolymph and protein hydrolysate of the bivalve mollusk Anadara kagoshimensis (Tokunaga, 1906)

Accumulation of Polychlorinated Biphenyls and Their Effects on Antioxidant Enzyme Activities in Tissues of the Ark Shell (Anadara kagoshimensis)

Accumulation of Polychlorinated Biphenyls and Their Effects on Antioxidant Enzyme Activities in Tissues of the Ark Shell (Anadara kagoshimensis)

Rapid on-site authentication of three cockle species using real-time loop-mediated isothermal amplification (LAMP) assay

Cockles, crucial for commercial fishing and aquaculture, emerge as highly marketable shellfish. However, the morphological similarities among various cockle species are frequently exploited for shellfish fraud. In this study, we developed LAMP assays (end-point LAMP and real-time LAMP) to detect three commercially important cockle species: Tegillarca granosa, Anadara broughtonii, and Anadara kagoshimensis. The primers were designed based on mitochondrial DNA and used to develop LAMP assays. Exclusivity was assessed using 17 shellfish species, and no cross-reactivity was confirmed. The estimate of the detection limit was determined to be 0.0001 ng. The established assays were further refined to create an on-site real-time LAMP assay by combining fast DNA isolation with a real-time fluorometer for field application. The effectiveness of the on-site real-time LAMP assay was successfully verified using 38 commercial samples, with analysis accuracy confirmed using a DNA extraction kit. Consequently, the on-site real-time LAMP assay can complete the whole procedure, including DNA extraction, real-time LAMP reaction, and data analysis within a 45 min timeframe, maintaining the accuracy of detecting three cockle species from processed cockle samples in the field. Our method proves valuable for detecting shellfish fraud by identifying cockle species using samples of both raw and processed products in the field.

Rare Earth Elements in Shells of Black Sea Molluscs: Anomalies and Biogeochemical Implications

Rare earth elements (REE) are a class of increasingly used high-tech product components and new emerging environmental pollutants, which are accumulated, in particular, in marine biota. In this study, REE contents were estimated in shells of several molluscs common in the Black Sea. The summed REE contents in mollusc shells decreased in the following order of species: Magallana gigas = Anadara kagoshimensis > Flexopecten glaber ponticus ≥ Rapana venosa > Mytilus galloprovincialis, ranging from 0.46 to 1.9 mg·kg−1. Canonical analysis of principal coordinates allowed for the correct identification of species based on the REE composition in no fewer than 67% of the samples. The mollusc shells were anomalously enriched in Sc, Y, La, Eu and Tb, most likely due to anthropogenic contamination. The Y/Ho ratios in all samples were represented by two fit values: 23.2 (chondritic) and 67.6 (superchondritic, mainly associated with A. kagoshimensis). A new universal relationship linking the contents of three light and heavy REE in Black Sea mollusc shells was proposed: Ce0.3 Er0.7/Yb = 2.00 ± 0.46 (mean ± standard deviation).

Deep learning-based phenotype classification of three ark shells: Anadara kagoshimensis, Tegillarca granosa, and Anadara broughtonii

The rapid and accurate classification of aquatic products is crucial for ensuring food safety, production efficiency, and economic benefits. However, traditional manual methods for classifying ark shell species based on phenotype are time-consuming and inefficient, especially during peak seasons when the demand is high and labor is scarce. This study aimed to develop a deep learning model for the automated identification and classification of commercially important three ark shells (Tegillarca granosa, Anadara broughtonii, and Anadara kagoshimensis) from images. The ark shells were collected and identified using a polymerase chain reaction method developed in a previous study, and a total of 1,400 images were categorized into three species. Three convolutional neural network (CNN) models, Visual Geometry Group Network (VGGnet), Inception-Residual Network (ResNet), and SqueezeNet, were then applied to two different classification sets, Set-1 (four bivalve species) and Set-2 (three ark shell species). Our results showed that SqueezeNet demonstrated the highest accuracy during the training phase for both classification sets, whereas Inception-ResNet exhibited superior accuracy during the validation phase. Similar results were obtained after developing a third classification set (Set-3) to classify six categories by combining Set-1 and Set-2. Overall, the developed CNN-based classification model exhibited a performance comparable or superior to that presented in previous studies and can provide a theoretical basis for bivalve classification, thereby contributing to improved food safety, production efficiency, and economic benefits in the aquatic products industry.

Erratum to: Effect of Hypoxia on Amino Acid Content in Hemolymph and Protein Hydrolysate of the Bivalve Mollusk Anadara kagoshimensis

Erratum to: Effect of Hypoxia on Amino Acid Content in Hemolymph and Protein Hydrolysate of the Bivalve Mollusk Anadara kagoshimensis

Effect of Hypoxia on Amino Acid Content in Hemolymph and Protein Hydrolysate of the Bivalve Mollusk Anadara kagoshimensis

Effect of Hypoxia on Amino Acid Content in Hemolymph and Protein Hydrolysate of the Bivalve Mollusk Anadara kagoshimensis

Dimensional and Weight Characteristics of the Bivalve Mollusk Anadara kagoshimensis (Tokunaga, 1906), an Alien Species in the Sea of Azov

Dimensional and Weight Characteristics of the Bivalve Mollusk Anadara kagoshimensis (Tokunaga, 1906), an Alien Species in the Sea of Azov

Adaptation of Anadara kagoshimensis (Tokunaga, 1906) to Hypo- and Hyperosmotic Environment: Hemocyte Response

Adaptation of Anadara kagoshimensis (Tokunaga, 1906) to Hypo- and Hyperosmotic Environment: Hemocyte Response

ADAPTATION OF ANADARA KAGOSHIMENSIS (TOKUNAGA, 1906) TO HYPO- AND HYPEROSMOTIC ENVIRONMENTAL CONDITIONS: HEMOCYTE RESPONSE

Anadara kagoshimensis (Tokunaga, 1906) is an invasive species that has successfully colonized the waters of the Black Sea and the sea of Azov, despite the significantly lower salinity level of these waters in comparison with the native region. The morphological and morphometric characteristics of bivalve mollusk A. kagoshimensis erythrocytes were analyzed by light microscopy during adaptation to hypo- and hyperosmotic experimental conditions. The control group of mollusks was kept at 18‰ salinity. Experimental groups were acclimated to 8, 14, 35 and 45‰ salinity. A decrease of salinity was achieved by diluting seawater with distilled water at a rate of 1.5±0.5‰ per day. Sea salt was added to each aquarium to increase salinity. Salinity was increased at a rate of 2.5±0.5‰ per day. Exposure period was 2 days. It has been shown that the salinity range of 14-35‰ is natural for ark clam. No significant changes in cell morphology were observed under these conditions. At the same time, environmental salinity levels of 8 and 45‰ caused obvious stress: cellular anomalies appeared, and the linear characteristics of erythrocytes were changed. However, cell lysis did not occur, the values of the specific surface area and nuclear-cytoplasmic ratio did not change. The results of the present work indicate the ability of the arc clam to exist for some time in regions with extremely low and high salinity of the aquatic environment.

SIZE AND WEIGHT CHARACTERISTICS OF THE BIVALVE MOLLUSC ANADARA KAGOSHIMENSIS (TOKUNAGA, 1906) - THE ALIEN SPECIES IN THE SEA OF AZOV

For the first time the research focuses on studying the size and weight characteristics of the alien species in the Sea of Azov - bivalve mollusc Anadara kagoshimensis (Tokunaga, 1906). The relationship between allometric parameters of the mollusc (size and weight) were approximated by the power function. The maximal coefficient of determination is found for the power dependence of the total weight of the anadara on the width of the shell, with minimum coefficient of determination depending on the height of the shell. The maximum coefficient of determination is obtained for the power dependence of the raw weight of soft tissues of anadara on the length of its shell, with the minimum coefficient of determination depending on the width of the shell. The ratio of dry and raw weight of soft tissues is 0.16. Under comparison of the different environmental areas of anadara in the Black, Aenean seas and the Sea of Azov, the hatchery housing of mollusks in waters with moderate salinity is found to be the most favorable condition for their maximal growth.

Effect of hypersalinic stress on hemocyte morphology and hemolymph cellular composition of the ark clam (Anadarakagoshimensis).

Bivalve mollusks as typical osmoconformers are unable to maintain a constant level of internal osmolarity in conditions of salinity stress. Adaptation to fluctuations of environmental salinity is achieved through cellular osmoregulatory responses, which are accompanied with a substantial shift in functional state of cells. In the present work we investigated the effect of hypersalinity stress on hemolymph cellular composition and morphology of the ark clam (Anadara kagoshimensis) hemocytes. Ark clams were subjected to a gradual increase of environmental salinity from 18‰ to 35‰ and 45‰ and maintained at those conditions for two days. Exposure to hypersalinity 35‰ induced changes in erythrocyte morphology and led to a decrease of their diameter. At salinity 45‰ a substantial increase of hemocyte average diameter was observed, whereas the shape of cells did not change (18‰). Hyperosmotic stress was not associated with changes in hemocyte viability as well as changes in hemolymph cellular composition. The results of the present work demonstrate high tolerance of A. kagoshimensis to short-time exposure to hypersalinic conditions.

Mollusc <i>Anadara kagoshimensis</i>, Allien Species, in Structures of the Benthic Communities on the Crimea Shelf

The frequency of occurrence of the mollusc-invader, Anadara kagoshimensis (Tokunaga, 1906), increased from 5 to 17–23% in zoobenthos of the South Coast of the Crimea Shelf for the last fifteen years. At the same time, the rate of the non-native mollusc was not significant and fluctuated: 0.73–23.29% from the biomass and 0.19–2.20% from abundance of the macrozoobenthos in the benthic communities. The mollusc A. kagoshimensis has been registered in the three communities: Chamelea gallina, Gouldia minima–Pitar rudis and Gouldia minima. The mollusc Anadara has not formed an independent community here. Influence of this alien species on bottom communities of the Crimean Coast was not such considerable as on bottom communities in northwest or in east parts of Black Sea Shelf. The structure of benthic communities had no significant changes on the shelf of the Southern Coast of the Crimea, compared with 70–80 of the last century. The first registration and the settlement of the mollusc-invader on the Crimea Shelf coincides with salinity decrease and temperature rise of coastal waters which are observed during last decade.

Functional changes in hemocytes and antioxidant activity in gills of the ark clam Anadara kagoshimensis (Bivalvia: Arcidae) induced by salinity fluctuations.

This study describes the analysis of antioxidant enzymatic activities (catalase and superoxide dismutase) in gills and functional state of hemocytes (osmotic stability, mitochondrial membrane potential) of ark clams (Anadara kagoshimensis) from the Black Sea basin exposed to salinity stress. For this, the effects of 48h periods of exposure to low (8 ‰, 14 ‰) and high (35 ‰, 45 ‰) salinity were assessed. Our results showed that ark clams, A. kagoshimensis, possessed pronounced tolerance to hypersalinity stress and are sensitive to a short-time hyposalinity treatment. Salinity 35 ‰ inhibited production of reactive oxygen species (ROS) by hemocytes and did not affect their levels of mitochondrial membrane potential. Acclimation to 45 ‰ salinity caused significant increase in mitochondrial membrane potential accompanied with recovery of intracellular ROS levels up to controls levels. Acclimation to low salinity (8 ‰) induced an increase in both ROS and mitochondrial membrane potential levels in hemocytes. Catalase and superoxide dismutase activity in gills decreased following acclimation to low (8 ‰) and high (35 ‰) salinity. Exposure to the highest salinity levels (45 ‰) led to a decrease of superoxide dismutase activity levels, but did not influence the levels of catalase activity. Acclimation to low and high salinity was not accompanied with changes in osmotic fragility of hemocytes despite osmotic fragility curve according to changes in hemolymph osmolarity. Based upon these results, we postulate the involvement of cellular osmoregulatory mechanisms in the adaptation of the ark clam to short-term fluctuations of environmental salinity.

Occurrence and spatial distribution of paralytic shellfish toxins in seawater and marine organisms in the coastal waters of Qinhuangdao, China

In recent years, paralytic shellfish toxins (PSTs) have been prevalent in the coastal waters of Qinhuangdao, the west coast of the Bohai Sea, China. The content of PSTs in shellfish often exceeded the regulatory limit of 800 μg STX equivalent (eq.) kg−1, which poses a serious threat to human health. In this study, two surveys were conducted in May 2021 and May 2022 to investigate the distribution of PSTs in the coastal waters of Qinhuangdao. Seawater, surface sediment, phytoplankton, zooplankton, and other marine organism samples were collected, and the composition and concentration of PSTs were analyzed by liquid chromatography with tandem mass spectrometry (LC-MS/MS). Results showed that multiple PST components were detected in all seawater samples collected at different depths, mainly including GTX1/4, GTX2/3, dcGTX2, STX and C1/2, and the highest concentration of PSTs reached 244 ng STX eq. L−1. The sediment samples also contained low levels of C1/2 and GTX2/3. Trace amounts of C1/2 and GTX1-4 were detected in phytoplankton and zooplankton. Moreover, all bivalve shellfish samples were found to contain PSTs, and the scallop Azumapecten farreri and the ark clam Anadara kagoshimensis showed relatively high concentrations of 607 and 497 μg STX eq. kg−1, respectively. In addition, low levels of PSTs were also found in some non-traditional PST vectors, including whelk Rapana venosa, octopus Amphioctopus ovulum, goby Ctenotrypauchen chinensis, and greenling Hexagrammos agrammus. Results of this study improve the understanding of the distribution of PSTs in seawater and marine organisms and the potential risk of persistent PSTs in seawater to marine ecosystems and human health.

Production of partially prepared food and ready-cooked foods from the meat of Azov Sea clams

The paper presents the results of studies of the technochemical composition and nutritional value of meat of four species of clams found in the Azov Sea: Anadara kagoshimensis (Tokunaga, 1906), Cerastoderma glaucum (Bruguière, 1789), Chamelea gallina (Linne, 1758) and Donax trunculus (Linnaeus, 1758). It is noted that almost the entire world catch, including aquaculture, is due to the use of shellfish for food and consumer demand for this group of marine invertebrates is stable, which is due to high organoleptic characteristics, nutritional value and low calorie content of their meat (250-350 kJ/100g). It was determined that the values of toxic elements in the clam meat did not exceed acceptable concentrations. A technological scheme for the production of boiled-frozen meat of burrowing mollusks has been developed, a brief description of the technological processes has been given, and the terms and conditions for storing the semi-finished product have been developed. An assortment of ready-cooked foods made from clam meat in various sauces and fillings was offered for tasting. Organoleptic evaluation of the samples revealed the preferences of the tasters, namely: the maximum scores were received by samples of chameleon in bechamel sauce (4.9±0.3) and donax stewed in wine sauce (4.8±0.3). The developed assortment can be offered for introduction into diets as a low-calorie delicacy product.

Population abundance and growth parameters of an exotic bivalve species, Anadara kagoshimensis, in the Southwestern Black Sea

Blood cockle (Anadara kagoshimensis) is an Indo-Pacific species that later entered the Black Sea. The abundance of A. kagoshimensis, which is not subjected to commercial fishing, is important in terms of food competition with other bivalvia species. Baby clam (Chamelea gallina) together with the A. kagoshimensis are dominant bivalve species found in the sandy and muddy areas off the coastal waters of the Black Sea. In this study, specimens of A. kagoshimensis have been recognized by morphological analysis and also confirmed by molecular characterization. Furthermore, the abundance and growth parameters of A. kagoshimensis were investigated in the Southwestern Black Sea. Blood cockles were sampled between February 2011 and December 2012, seasonally. According to the Von Bertalanffy Growth Parameters (VBGP) the results were L$_{∞}$ = 81.96 mm, K = 0.32 year$^{-1}$, t$_{0}$ = -0.22 year, and nonseasonal L$_{∞}$ = 84.32 mm, K = 0.31 year$^{-1}$, t$_{0}$ = -0.21, WP = 0.65, t$_{s}$ = 0.15. The growth pattern showed the slope [b] = 2.96-3.01 in 2011 and 2012. The stock size was estimated according to two different years in 5 different subareas (Cide, İnebolu, Türkeli, Ayancık, and Sarıkum) and by 4 different strata (0-5 m, 5-10 m, 10-15 m, and 15-20 m). Considering subareas, the A. kagoshimensis population in all subareas increased significantly in a single year. Compared to other regions, İnebolu was the main highly distributed area of the A. kagoshimensis, and also the estimated stock size was the highest in the region. Due to food competition with other commercial species (mainly Chamelea gallina) A. kagoshimensis is an ecology important species for the Southern Black Sea habitats. It is aimed to make contributions to Good Environmental Status (GES) and fisheries management in the region.

Chemical status evaluation of the Romanian Black Sea marine environment based on benthic organisms’ contamination

The use of living organisms to provide information on the quality of aquatic environments is now a widely accepted methodology for assessing contaminant bioavailability. Molluscs have developed tolerance mechanisms towards environmental stressors and can accumulate a large range of contaminants. The assessment of marine environment quality was based on heavy metals (HM), persistent organic pollutants (organochlorine pesticides – OCPs and polychlorinated biphenyls - PCBs) and polynuclear aromatic hydrocarbons (PAHs) analysis in Mytilus galloprovincialis, Rapana venosa, Anadara kagoshimensis species sampled during 2016 - 2020 along Romanian Black Sea coast. Toxic metals (cadmium, lead) had bioaccumulation levels below threshold values in most molluscs samples investigated. Cadmium registered few values (15%) surpassing maximum admissible levels, in all three species. Data evaluation demonstrated the maintenance of a high level of concentrations of persistent organic pollutants in the mollusc tissue, but also of the exceedances of the values that characterize the good ecological status of these compounds. Polynuclear aromatic hydrocarbons showed a declining trend and no exceeding of the maximum allowed limit for benzo[a]pyrene was recorded in the last years. In consequence, the overview assessment based on “OneOutAllOut” (OOAO) approach, considering all groups of substances, indicates a bad chemical status for this period.

Dietary Changes in the Ark Clam (Anadara kagoshimensis) Is Associated with Phytoplankton Community Patterns in a Temperate Coastal Embayment

The monthly phytoplankton communities and dietary items of the filter-feeding ark clam (Anadara kagoshimensis) in cultivation were examined in a shallow temperate coastal embayment of Yeoja Bay in Korea, to identify dietary changes in clams associated with phytoplankton community patterns. A self-organizing map (SOM) algorithm was applied to shape the community structures of phytoplankton. Clam δ13C and δ15N values were determined monthly and compared with those of phytoplankton, microphytobenthos, suspended particulate organic matter (SPOM), sedimentary organic matter (sedimentary OM), and Phragmites australis. Our SOM clustered monthly phytoplankton communities, revealing a seasonal shift in the dominance of large-sized diatoms (sporadically together with dinoflagellates), which were detected almost year-round, to small-sized taxa (chlorophytes, prasinophytes, and prymnesiophytes), which were observed in May–June. The δ13C and δ15N measurements revealed that pelagic and benthic diatoms serve as the main contributors to the clam diets. A reduction in their dietary contribution accompanied a considerable increment in the contribution of Phragmites detritus in association with the dominance of small-sized phytoplankton during the late spring. Our results suggest that the dominance of small-sized phytoplankton during the critical spring period of the clam life cycle may decrease the availability of preferred items (i.e., size-related food quality) and lead to dietary changes in the clams in relation to climate forcing in this warming sea.