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This study evaluates the potential of red blood cockle Tegillarca granosa as a biomonitor for heavy metal contamination in coastal environments, with a focus on the differential bioaccumulation patterns across three sites: Teluk Kemang (TK), Pasir Panjang (PP), and Port Dickson (PD). Four major findings emerged from the analysis. First, T. granosa demonstrated significant variations in metal accumulation, with PD exhibiting the highest concentrations of Zinc (Zn), Copper (Cu), and Iron (Fe). This confirms the species' sensitivity to varying pollution levels and highlights PD as the most contaminated site among the three. Second, strong correlations between metal levels in the environment and their accumulation in the cockle’s soft tissues underscored its effectiveness in reflecting the bioavailability of contaminants, particularly for Zn and Cu. This finding validates the use of T. granosa as an effective bioindicator of environmental metal exposure. Third, the study highlighted the role of cockle shells as indicators of long-term exposure, with consistently higher metal concentrations observed at PD. This suggests persistent environmental contamination in this area and demonstrates the value of shell analysis in assessing chronic pollution. Finally, the stepwise multiple regression analysis revealed complex interactions between environmental media and bioaccumulation processes, emphasizing the need for a comprehensive approach to biomonitoring. These interactions indicate that bioaccumulation in T. granosa is influenced by multiple environmental factors, necessitating an integrated monitoring strategy. These findings support the use of T. granosa as a reliable indicator species for monitoring heavy metal pollution and assessing ecological risks in coastal ecosystems.

The common cockle (Cerastoderma edule) plays an important role in marine ecosystems and represents a valuable socioeconomic resource for coastal communities. In 2012, the cockle beds from Rı́a de Arousa (Galicia, NW Spain) were seriously decimated by the protozoan Marteilia cochillia responsible for marteiliosis. We aimed to identify single nucleotide polymorphisms (SNP) markers potentially associated with resilience to marteiliosis to be used in marker-assisted selection programs for restoring affected cockle beds and recovering their production. For this, we carried out a population genomics approach using 2b-RADseq, where 38 naive samples (before the first detection of M. cochillia in 2012) from two beds of Rı́a de Arousa were compared with 39 affected samples collected in 2018/2019 (after several years of marteiliosis occurring in the area), collected either before (15 non-exposed samples) or during (24 exposed samples) the marteiliosis outbreak. Additionally, 767 differentially expressed genes (DEG) from a previous transcriptomic study addressed during the aforementioned 2018/19 marteiliosis outbreak, were evaluated to identify SNPs showing signals of selection. Using 2b-RADseq, 9,154 SNPs were genotyped and among them, 110 consistent outliers for divergent selection were identified. This set of SNPs was able to discriminate the samples according to their marteiliosis status (naive vs affected; exposed vs non-exposed), while another 123 SNPs were identified linked to DEGs associated with the level of infection across a temporal series. Finally, combining the population genomics and transcriptomics information, we selected the 60 most reliable SNPs associated with marteiliosis resilience. These SNPs were close to or within DEGs, and many of them were related to immune response (phagocytosis and cell adhesion), defence, such as apoptosis, stress, and cellular cycle, among other functions. This set of SNPs will eventually be validated to develop a cost-effective genotyping tool for their application for obtaining cockle-resilient strains for marteiliosis.

Abstract Reproduction and parasites have significant impacts on marine animal populations globally. This study aimed to investigate the associative effects of host reproduction and a host–parasite interplay on a marine bivalve, along a geographic gradient of latitude. Cockles Cerastoderma edule were sampled from five European sites (54°N to 40°N), between April 2018 and October 2019. A histological survey provided data on trematode (metacercaria and sporocyst life stages), prevalence, and cockle stage of gametogenesis to assess the influence of a latitudinal gradient on both interplays. Sex ratios at the northernmost sites were skewed toward females, and spawning size was reduced at the lower latitudes. Trematode infection did not follow a latitudinal gradient. Localized site‐related drivers, namely seawater temperature, varied spatially, having an impact on cockle–trematode interactions. Spawning was related to elevated temperatures at all sites. Prolonged spawning occurred at southern latitudes, where seawater temperatures were warmer. Trematode prevalence and the impact of trematodes on gametogenesis were found to be spatially variable, but not latitudinally. Therefore, it is not possible to determine the likelihood of boom and bust events in cockles, based on the latitudinal location of a population. In terms of sublethal impacts, it appeared that energy was allocated to reproduction rather than somatic growth in southern populations, with less energy allocated to reproduction in the larger, northern cockles. The demonstrated spatial trend of energy allocation indicates the potential of a temporal trend of reduced cockle growth at northern sites, as a result of warming sea temperatures. This awareness of the spatially varying drivers of populations is crucial considering the potential for these drivers/inhibitors to be exacerbated in a changing marine environment.

The concentrations of Cd, Cu and Zn have been determined in the tissues and the cytosolic fraction of the common cockle, Cerastoderma edule, collected from sediments in the Tamar, Plym and Avon estuaries (South West, England). Metal concentrations in the tissues of C. edule from the Avon were lower than those from the Tamar and Plym, except for Cu in the digestive gland. Significant statistical relationships were only obtained between the total sedimentary metal concentrations and Cd in the body of C. edule and Cu in the digestive gland. The cytosolic fraction was extracted from each of the tissues and separated for protein analysis thereby allowing determination of the metal contents in high molecular weight (HMW) compounds, metallothionein-like proteins (MTLP) and very low molecular weight (VLMW) compounds. The digestive glands of C. edule from the Avon had relatively low concentrations of MTLP, whereas MTLP concentrations in the digestive gland of cockles from the Tamar and Plym were higher. The cytosolic fraction of C. edule had relatively low total Cd and Cu concentrations associated with MTLP, whereas Zn was preferentially associated with the HMW and the VLMW components. The results are relevant to metal distributions in C. edule and the role of cytosols in the management of metals by C. edule and other invertebrates. Cerastoderma edule Gel chromatographic separation of Zn molecular weight complexes in cockle cytosols. HMW (high molecular weight); MTLP (metallothionein-like protein; VLMW (very low molecular weight protein). [Display omitted] • Cd, Cu & Zn were determined in tissues and cytosolic fractions of C. edule from UK estuaries. • Biota-sediment metal accumulations in C. edule tissues were highest for Cd and very low for Cu. • Metallothionein concentrations were elevated in estuaries with metal-rich sediments. • Zinc in the cytosolic fractions of C. edule had a specific preference for the HMW fraction. [ABSTRACT FROM AUTHOR]

Reproduction and parasites have significant impacts on marine animal populations globally. This study aimed to investigate the associative effects of host reproduction and a host–parasite interplay on a marine bivalve, along a geographic gradient of latitude. Cockles Cerastoderma edule were sampled from five European sites (54°N to 40°N), between April 2018 and October 2019. A histological survey provided data on trematode (metacercaria and sporocyst life stages), prevalence, and cockle stage of gametogenesis to assess the influence of a latitudinal gradient on both interplays. Sex ratios at the northernmost sites were skewed toward females, and spawning size was reduced at the lower latitudes. Trematode infection did not follow a latitudinal gradient. Localized site‐related drivers, namely seawater temperature, varied spatially, having an impact on cockle–trematode interactions. Spawning was related to elevated temperatures at all sites. Prolonged spawning occurred at southern latitudes, where seawater temperatures were warmer. Trematode prevalence and the impact of trematodes on gametogenesis were found to be spatially variable, but not latitudinally. Therefore, it is not possible to determine the likelihood of boom and bust events in cockles, based on the latitudinal location of a population. In terms of sublethal impacts, it appeared that energy was allocated to reproduction rather than somatic growth in southern populations, with less energy allocated to reproduction in the larger, northern cockles. The demonstrated spatial trend of energy allocation indicates the potential of a temporal trend of reduced cockle growth at northern sites, as a result of warming sea temperatures. This awareness of the spatially varying drivers of populations is crucial considering the potential for these drivers/inhibitors to be exacerbated in a changing marine environment. [ABSTRACT FROM AUTHOR]

Studies on marine community structure and their modulation by horizontal and vertical abiotic gradients have focused on free-living species, neglecting parasites despite their important role in ecosystems. Field observations, a laboratory flume experiment and modelling were used to examine parasite infection patterns related to host tidal and spatial position along a Portuguese coastal lagoon (Ria de Aveiro). Cockles (Cerastoderma edule) and trematodes were used as a host-parasite model to test the hypotheses: (1) higher infection levels in subtidal cockles, positioned downstream and (2) higher current velocity in downstream areas with consequent higher cockle infection. Cockles were collected from two spatial and tidal positions in two seasons. The relationship between current velocity and cockle infection was examined experimentally by exposing cockles to cercariae of Himasthla elongata at two current velocities. Intertidal cockles displayed higher infection, highlighting vertical position as an important driver of infection possibly due to first host proximity and/or trematode life cycle facilitation (higher cockle exposure to final host predation). The hydrodynamic model showed that the Ria de Aveiro was abiotically heterogenous with cockles displaying higher infection levels in the downstream area. Multiple regression analysis demonstrated a positive correlation between salinity, dissolved oxygen, current velocity and trematode abundance. The influence of current velocity on infection success was corroborated experimentally. The present study demonstrated the importance of host vertical and horizontal position on trematode infection, highlighting the positive influence of current velocity by supporting settlement and promoting favourable abiotic conditions. [ABSTRACT FROM AUTHOR]

The present study aimed to investigate the incidence, virulence and antibiotic properties in Vibrio spp. isolated from cockles (Tegillarca granosa) marketed in Korea. A total of 32 Vibrio spp. isolates including V. parahaemolyticus (n = 4), V. alginolyticus (n = 11), V. diabolicus (n = 14) and V. harveyi (n = 3) were detected using gyrB sequencing. The phenotypic pathogenicity revealed that the DNase, amylase and phospholipase activities were 100%, while lipase, slime production, gelatinase and caseinase were detected in 72, 88, 88 and 81% of the isolates respectively. The PCR amplification for the detection of V. parahaemolyticus species‐specific tdh, tlh, trh and toxR genes were positive in 4 (13%), 16 (50%), 0 (0%) and 4 (13%) isolates respectively. The V. alginolytuicus species‐specific tdh, tlh, trh, toxR and vac genes were carried by 15 (47%), 29 (91%), 0 (0%), 15 (47%) and 25 (78%) of the isolates respectively. In addition, multidrug resistance was observed by 27 (84%) isolates, whereas higher resistant rates were observed against ampicillin, piperacillin, streptomycin and cephalothin. The occurrence of blaCTX (78%), blaTEM (40%), blaSHV (22%) and aac(6')‐Ib (94%) were prevalent, while strAB, tetB, aphAI‐IAB, intl1 and aadA1 gene cassettes were also detected. The results signify the potential health risks resulting from the consumption of raw cockles in Korea. Significance and Impact of the Study: Vibrios are well known to cause human infections following consumption of raw or undercooked seafood. This phenomenon has undoubtedly increased the number of health issues over the past few years in Korea. Among the identified Vibrio spp., we could detect V. diabolicus and V. harveyi for the first time in marketed cockles in Korea. The presence of species‐specific genes (tdh‐VA, tlh‐VP, tlh‐VA and toxR‐VA) in V. diabolicus exhibits the close genetic affinity among V. parahaemolyticus and V. alginolyticus. Furthermore, the prevalence of extended‐spectrum β‐lactamases (ESBLs) and other antibiotic resistance genes along with multidrug resistance signifies the potential threat for consumers. [ABSTRACT FROM AUTHOR]

Activities of Po-210 in cockles Anadara granosa around Peninsular Malaysia have been determined by Alpha Spectrometry using a radiochemical separation technique. The results showed that Po-210 activity distribution varies according to sampling sites. The range of activity was 2.61 ± 1.50 to 309 ± 26 Bq/kg. The lowest mean was recorded from Kuala Selangor and the highest mean was from Mersing. The activity pattern shown by this radionuclide was a decrease with an increase in cockles mass. The activity was higher in cockles of smaller sizes than the larger sized cockles, a pattern attributed to their digestion and metabolism system. The activity intake and effective dose was found to be less than international guidelines and seafood intake was considered safe for human consumption. These findings suggest that regular monitoring should be carried out to help reduce morbidity and mortality among humans as a result of occasional seafood consumption.

Cockles (Tegillarca granosa) species that found throughout the Indo-Pacific region and this study was conducted in South Korea from late autumn (November 2015) through early spring (April 2016). The proximate composition, mineral content, free amino acid, and fatty acid (FA) profiles and the nutritional quality of the cockles were studied at different stages during the processing. The contents of protein (11.7–13.9/100 g), lipids (1.1–2.5/100 g) and ash (1.6–2.7/100 g) varied significantly (p

The objective of this study was to evaluate the effect of salinity on the survival of bivalve mollusc Anomalocardia brasiliana. The experiment consisted of six treatments with the salinities 5, 15, 25, 35, 45 and 55 mg L-1, with eight replications each. The experiment was conducted with water temperature at 28 °C and photoperiod of 12 h, with Dissolved Oxygen (DO) at 4.86 mg L-1 and 60.28% and a pH 7.0. Daily we monitorated these parameters. In each experimental unit, with constant aeration and volume of 3 liters, were placed 18 individuals of A. brasiliana. Three individuals of each experimental unit were removed at times 12, 24, 48, 72, 96 and 240 h after the start of the experiment to verify whether they were alive or dead. All dead individuals removed were discarded, not returning to the experimental unit. Treatments with salinities 5 and 55 mg L-1 had higher mortality, not presenting any individual living at 240 h. For other treatments 15, 25, 35 and 45 mg L-1 occurred survival until the end of the study at 240 h. It was found that the treatments of 15, 25, 35 and 45 mg L-1 showed no significant difference with regard to survival or mortality. It can be concluded that the greater survival occurred in the salinity range 15 to 45 mg L-1. This allows us to infer that, despite being a euryhaline species, with great tolerance to hyperosmotic media, salinity shock affected the survival and may have caused the death of individuals. [ABSTRACT FROM AUTHOR]

Cardiids or marine cockles are one of the best known families of marine bivalves in the world, with a long history of study and collection given their large and accessible shells, a tractable level of biodiversity globally (~290 species) and a solid fossil record extending to the late Triassic. In Western Australia, the cardiids are well known relative to other marine bivalve families, having been the subject of focussed treatment and consist of 31 species. However, given the proximity to the Indo-West Pacific, sheer size of the state and almost unparalleled number of habitats, the diversity is likely underestimated. Over the last 40 years, ongoing expedition work coupled with taxonomic study by the authors, has resulted in a doubling of the cardiid fauna of Western Australia (WA). Current cardiid diversity now stands at 68 species, including seven species of giant clams (Tridacninae). Subfamilial representation has changed little (except for the addition of Tridacninae previously in its own family, the Tridacnidae), and key genera in Cardiinae (e.g. Fulvia), Fraginae (e.g. Fragum) and Trachycardiinae (e.g. Acrosterigma and Vasticardium) still deliver much of the diversity. This updated biodiversity census has implications within and beyond Western Australia, with 16 new species records for the state and 14 new records for Australia, including four new species: Acrosterigma extremattenuatum sp. nov., Ctenocardia pilbaraensis sp. nov., Microcardium scabrosum sp. nov. and Pratulum occidentale sp. nov. Further taxonomic decisions include recognition of Vasticardium serricostatum (Melvill & Standen, 1899) and Lunulicardia tumorifera (Lamarck, 1819) as distinct species. Vasticardium swanae Maxwell, Congdon & Rymer, 2016 is considered a new synonym of Cardium variegatum G.B. Sowerby II, 1840; Vasticardium lomboke Vidal, 2003 is considered a new synonym of Cardium mindanense Reeve, 1844 and Acrosterigma abrolhense Vidal, 1999 is considered a new synonym of Cardium cygnorum Deshayes, 1855. All subspecies in the Vasticardium elongatum (Bruguière, 1789) complex are raised to species level. New acquisitions arising from tropical survey work in the north have yielded all of the newly added species and all newly described species in the Western Australian Museum (WAM) cardiid collections. This is in contrast to the relatively stable biodiversity of southwestern Western Australia. In the north, diversity is highly structured with sixteen taxa found restricted to offshore islands and shoals (e.g. Vasticardium philippinense (Hedley, 1899), V. elongatum (Bruguière, 1789), Corculum cardissa (Linnaeus, 1758), Ctenocardia fornicata (G.B. Sowerby II, 1840), C. gustavi Vidal & Kirkendale, 2007), and a smaller cohort found exclusively inshore (e.g. A. extremattenuatum sp. nov., V. wilsoni (Voskuil & Onverwagt, 1991), C. pilbaraensis sp. nov.). Biodiversity comparisons are made with other tropical states in northern Australia, including the Northern Territory (NT) and Queensland (Qld), and considered together these records support recognition of a vast Dampierian Province. Regional biogegraphic comparisons are also made to examine whether cardiids in northern Australia are as diverse as other central Indo West Pacific (IWP) areas. To improve management of the commercially important Tridacninae (giant clams), we provide the first formal records of species diversity and distribution in this group for WA. While cardiids are relatively well characterised, persistent gaps remain that are not unique to this family. Our knowledge of small and/or cryptic species, as well as the deep water fauna broadly, lags behind our understanding of shallow water macromolluscs. [ABSTRACT FROM AUTHOR]

The present study investigated the potential application of the bacteriophage (or phage) phT4A, ECA2 and the phage cocktail phT4A/ECA2 to decrease the concentration of Escherichia coli during the depuration of natural and artificially contaminated cockles. Depuration in static seawater at multiplicity of infection (MOI) of 1 with single phage suspensions of phT4A and ECA2 was the best condition, as it decreased by ∼2.0 log CFU/g the concentration of E . coli in artificially contaminated cockles after a 4 h of treatment. When naturally contaminated cockles were treated in static seawater with single phage suspensions and the phage cocktail, similar decreases in the concentration of E . coli (∼0.7 log CFU/g) were achieved. However, when employing the phage cocktail, a longer treatment time was required to obtain comparable results to those achieved when using single phage suspensions. When naturally contaminated cockles were depurated with phage phT4A in a recirculated seawater system (mimicking industrial depuration conditions), a 0.6 log CFU/g reduction of E . coli was achieved after a 2 h of treatment. When the depuration process was performed without phage addition, a 4 h treatment was necessary to obtain a similar decrease. By combining phage therapy and depuration procedures, a reduction in bivalves depuration period can be achieved for, thus decreasing the cost associated with this procedure and even enhance the quality and safety of depurated bivalves destined for human consumption. [ABSTRACT FROM AUTHOR]

Vibrio parahaemolyticus is a main foodborne disease in seafood and generally seafood is easily deteriorates in quality of color and flavor. In this study, clove (Syzygium aromaticum) extract shows potent antibacterial activity against growth of antibiotics resistant Vibrio parahaemolyticus on seafood samples (cockles and shrimps). Vibrio parahaemolyticus was artificial contaminates on the samples with 106 CFU/ml. The samples were treated with different concentration of cloves extract with 10 mg/ml which are 0.5%, 5% and 10% concentration from methanol food grade extraction in 0 hr, 5 min, 10 min, 15 min, 30 min, 60 min and 120 min. Tab water and deionized water were selected as a negative control. As a result, the amount of 10 % cloves managed to mitigates the number of V. parahaemolyticus on seafood samples in 5 minutes and 15 min on both samples. Therefore, our results signify the fact that cloves can be apply as natural sanitizer which could meet consumer demands for safe and traditionally consumed either raw without any undesirable effect when applied in the seafood system industries. [ABSTRACT FROM AUTHOR]

As bivalve molluscs are filter feeder, often consumed raw or lightly cooked and are frequently cultivated in contaminated waters, they are implicated in food-borne disease transmission to human. The present study investigated the potential application of bacteriophage (or phage) phSE-2, phage phSE-5 and phage cocktail phSE-2/phSE-5 to decrease the concentration of Salmonella enterica serovar Typhimurium ( Salmonella Typhimurium) during the depuration of natural and artificially contaminated cockles ( Cerastoderma edule ). Cockles were artificially infected with 10 5 and 10 6 colony-forming units (CFU)/mL of S . Typhimurium in static seawater and infected group were treated with phages at four different MOI values: 0.1, 1, 10 and 100. Depuration in static seawater at multiplicity of infection (MOI) of 0.1 with single phage suspensions of phSE-2 and phSE-5 provided the best results, as it decreased by ~ 1.3 and 1.7 log CFU/g, respectively, the concentration of Salmonella spp. after a 4 h treatment. At a MOI of 0.1, the rate of inactivation with single phage suspensions was higher when compared with the results obtained using the phage cocktail. However, in naturally contaminated cockles treated in static seawater with single phage suspensions and phage cocktail phSE-2/phSE-5, similar decreases in cultivable bacteria concentration (~ 0.7–0.9 log CFU/g) were achieved after 6 h of treatment. When artificially contaminated cockles were depurated with phage phSE-5 in a recirculated seawater system (mimicking industrial depuration conditions), a 0.9 and 2.0 log CFU/g reduction of Salmonella spp. was reached after 4 and 6 h treatment. Once the depuration process was performed without phage, a 6 h treatment was needed to obtain a 1.1 log CFU/g reduction of Salmonella spp. Results indicated that combining phage biocontrol with depuration procedures enhance bivalve microbial safety for human consumption by improving decontamination efficiency, proving that this technology can be transposed to the bivalves industry. Moreover, this approach also displays the advantage of reducing the time required for depuration and consequently its associated costs. [ABSTRACT FROM AUTHOR]

Live cockles were eroded from a tidal flat by a storm event and naturally transported to a nearby dike and beach. Their fate was observed regularly for two months. Some died from desiccation high on the shore, and some were consumed by oystercatchers. Others were caught by the byssus threads of mussels inhabiting the intertidal area, while a few tried to reburrow high on the shore. These cockles were supposedly rolled while being transported to the beach and were later observed being rolled by the waves just below the high water line. Hence, it was concluded that the shells were subjected to abrasion and that this was the cause of the holes that some individuals developed near the umbo of one or both of their (still articulated) valves. A few had repaired such holes, supporting the hypothesis that these holes were made during rolling transportation. Similar shell assemblages of articulated cockleshells partly with subumbonal; holes were later found elsewhere on the Wadden Sea coast of Texel. This “natural” experiment and the repair indicated that this abrasion occurred while the cockles were still alive, and not after their death. It may also help to better discriminate between biologically and physically produced traces on shells. [ABSTRACT FROM AUTHOR]

Numerous marine populations experience parasite pressure. This is the case of the cockles Cerastoderma edule which are often highly infected by trematode macroparasites. These parasites display a complex life cycle, with a succession of free-living and parasitic stages. Climate, and in particular temperature, is an important modulator of the transmission dynamics of parasites. Consequently, global change is thought to have implications for the epidemiology of infectious diseases. Using Himasthla quissetensis , a dominant parasite of cockles as 2nd intermediate host in Arcachon Bay (France), we used mathematical models of parasite emergence (cercariae) and parasite infection (metacercariae) in cockles as a function of water temperature, in order to study different scenarios of temperature increases. Globally, with a + 0.5 °C to + 6.0 °C simulation, cumulated emergence of cercariae and accumulation of metacercariae tended to decrease or stagnate, respectively. This is the consequence of a trade-off between sooner (spring) and later (autumn) cercariae emergence/infestation on one hand, and a longer inhibition period of cercariae emergence/infestation during the hottest days in summer. Using sea water temperature in Oualidia (Morocco) where mean annual sea temperature is 3 °C higher than in Arcachon Bay, our model predicted infestation all year long (no seasonality). The model gave a correct estimation of the total number of parasites that was expected in cockles. Conversely, observed infestation in Oualidia followed a seasonal pattern like in Arcachon Bay. These results suggest that, if temperature is a strong driver of parasite transmission, extrapolation in the framework of climate change should be performed with caution. [ABSTRACT FROM AUTHOR]

Bivalves are frequently used to assess environmental contamination, and are often considered good sentinel and/or bioindicator species. For that reason the bioaccumulation and toxicity induced by metals and As in the cockle Cerastoderma glaucum , collected from areas with different contamination levels along the Óbidos lagoon (Portugal), were used to evaluate the use of this species as sentinel and/or bioindicator. The results showed that areas in the middle of the lagoon presented lower metals and As concentrations, lower total organic matter content and lower percentage of fine particles than areas in the Bom Sucesso arm. In all areas Cr, Pb and Cu were the most abundant elements, while Ni, As, Cd and Hg were less abundant. Results also showed a moderate correlation between total elements concentrations found in C. glaucum and in sediment, and thus caution should be taken when considering this species as a good sentinel species. The present study also revealed that, in general, C. glaucum from areas in the middle of the lagoon accumulated higher concentrations of metals and As (Biota-Sediment Accumulation Factor >1) than cockles from the most polluted areas located in the Bom Sucesso arm. However, in all areas, the majority of metals (Cu, Cr, Pb) were found in cockles insoluble fraction which may explain low cellular damage and reduced oxidative stress responses observed. Therefore, our results may further alert for caution when identifying C. glaucum as a good bioindicator species. Thus, our findings highlight the fact that studies should be cautious when selecting species for environmental monitoring, since good sentinels or bioindicators in highly polluted systems may not act in the same way in low or moderately contaminated areas. Furthermore, our study warns for the misclassification of cockles in different ecosystems. [ABSTRACT FROM AUTHOR]

This study measured the levels of total mercury (tHg) in the whole tissues of cockles ( Anadara granosa and A. antiquata) harvested from three estuaries of Western Lombok Island (WLI), Indonesia. This paper also evaluated the hazard level posed by the mercury in relation to the maximum residual limit for human consumption and to estimate the weekly intake and compare it with the provisional tolerable weekly intake (PTWI). The tHg concentrations in A. granosa ranged from 0.020 to 0.070 mg kg, and those in A. antiquata were between 0.032 and 0.077 mg kg at all locations. All samples of cockles harvested from WLI contain tHg below the permissible limit for human consumption. The maximum weekly intakes for total mercury by coastal people range from 0.28 to 1.08 µg kg b.w., and they are below the recommended values of PTWI (5.6 µg kg b.w.). If it is assumed that 100 % of the Hg in cockles is methyl mercury (MeHg), consumption of the indicated amounts at the measured values wouldn't exceed the MeHg PTWI (1.6 µg kg b.w.). [ABSTRACT FROM AUTHOR]

Activities of Po-210 in cockles Anadara granosa around Peninsular Malaysia have been determined by Alpha Spectrometry using a radiochemical separation technique. The results showed that Po-210 activity distribution varies according to sampling sites. The range of activity was 2.61 ± 1.50 to 309 ± 26 Bq/kg. The lowest mean was recorded from Kuala Selangor and the highest mean was from Mersing. The activity pattern shown by this radionuclide was a decrease with an increase in cockles mass. The activity was higher in cockles of smaller sizes than the larger sized cockles, a pattern attributed to their digestion and metabolism system. The activity intake and effective dose was found to be less than international guidelines and seafood intake was considered safe for human consumption. These findings suggest that regular monitoring should be carried out to help reduce morbidity and mortality among humans as a result of occasional seafood consumption. [ABSTRACT FROM AUTHOR]

Hydraulic dredging for bivalves, such as cockles (Cerastoderma edule), has the potential to cause significant impacts on marine intertidal benthos. Although this fishing activity is common in northern European Natura 2000 sites such impacts may be incompatible with conservation objectives for designated habitats and species within these sites. In 2009–2010 a spatially nested control-impact study was undertaken before (t0), 8–9 days after (t1) and 4 months (t2) following dredging and extraction of 108 tonnes of cockles from a standing stock of 2158 tonnes in Dundalk Bay. This study failed to detect significant effects on benthic sediments, or the overall community structure. However, a fishing effect on the target species C. edule in one sampling area and a short lived effect on the bivalve Angulus tenuis were identified. Significant spatial and temporal variability in abundance of species and taxonomic groups, unrelated to fishing effects, was observed. Previous studies on the effects of fisheries on marine intertidal benthos have reported variable results, related to study design and objectives and the physical characteristics of the study site. Site specific studies, relative to the intensity and frequency of proposed fishing activity, may be required to adequately inform managers whether such activities are compatible with specific conservation objectives for Natura 2000 sites. [ABSTRACT FROM PUBLISHER]

Highlights: [•] Cockles were collected from a natural bed in Cambados (Spain). [•] Genes involved in cancer development were sequenced in cockles. [•] Cell and tissue biomarkers, the transcription level of cancer-related genes and mutations in ras gene were analysed in healthy and neoplastic cockles. [•] 12.3% of the cockles analysed suffered disseminated neoplasia. [•] Neoplastic cockles showed higher transcription levels of p53 and ras than healthy cockles and mutational alterations in ras gene sequence were detected. [Copyright &y& Elsevier]

A systematic review of the parasites, pathogens and commensals of the edible cockle (Cerastoderma edule) and of the lagoon cockle (Cerastoderma glaucum) has been completed. A total of 59 different conditions have been reported throughout the range of both of these hosts; of these 50 have been reported in edible cockles, and 28 in lagoon cockles. Cockles are hosts to viruses, bacteria, fungi (including Microsporidia), Apicomplexa, Amoeba, Ciliophora, Perkinsozoa, Haplosporidia, Cercozoa, Turbellaria, Digenea, Cestoda, Nematoda, Crustacea and Nemertea. A number of these have been reported sporadically although they may be associated with mortalities. In particular, mortalities have been associated predominately with digeneans and some protistan infections. In many cases pathology is marked in affected animals and parasites have been shown to reduce fecundity, alter burrowing behaviour and limit growth. This review provides information on the individual and population effects of these conditions as well as providing suggestions for future research. In particular, there has been a lack of taxonomic rigour applied to many studies and as a result there are a number of erroneous host records. There is a need to re-describe a number of parasite species and to determine the life cycle of those considered to be important mortality drivers. [ABSTRACT FROM PUBLISHER]

Abstract: Physiological responses can be used as effective parameters to identify environmentally stressful conditions. In this study, physiology changes such as oxygen consumption, clearance rate, survival in air, condition index and energy reserves were measured on natural populations of cockles collected from different sites at Ria de Aveiro, Portugal. At those sites, sediment samples were collected for Hg concentration analysis. Cockles were used for the evaluation of both the Hg concentration and physiological response. Mercury was detected in the cockle tissue and in the sediment collected from the sampling points both nearby and distant from the main mercury contamination source. The energy content was negatively correlated with both Hg concentration in cockle tissues and survival in air. Nonetheless, the energy content was positively correlated with the condition index, and there was a positive correlation between the survival in air test and the tissue mercury concentration. A PCA-factor analysis explained 86.8% of the total variance. The principal factor (62.7%) consisted of the air survival, the Hg in soft tissues (positive) and the condition index (negative). The second factor (24.1%) consisted of a negative correlation between the oxygen consumption and the clearance rate. Due to their sensitivity to environmental conditions, the physiological responses of cockles can be used to assess the ecological status of aquatic environments. More effort should be invested in investigating the effects of environmental perturbations on cockle health once they are a good reporter organism. [Copyright &y& Elsevier]

A total of sixty V. parahaemolyticus strains isolated from local cockles (Anadara granosa) were investigated by their antibiotic resistance patterns and plasmid profiles. The isolates showed multiple resistances towards most of the antibiotics tested. All strains of V. parahaemolyticus isolated harbored 1-3 plasmids, with sizes ranging from 2.7 to 54 kb. All V. parahaemolyticus strains showed high multiple antibiotics in frequencies of 0.58 - 0.94 indicating that the strains were derived from high-risk sources. In addition, no particular plasmid profile was predictive of a particular pattern of antibiotic susceptibility. These findings are essential because of the suggested involvement of seafood especially shellfish and environment in transmission of this pathogen to human. Thus, indicating that seafood may be a source of food- acquired antibiotic resistant bacteria to consumer. [ABSTRACT FROM AUTHOR]

The article discusses a study on the concentration levels of polychlorinated biphenyls (PCBs), HCB and dichlorodiphenyl trichloroethane (DDT) and derivatives, aldrin, heptachlor and its epoxide in clams, cockles and oysters from the Khnifiss Lagoon ecosystem on the South Atlantic coast of Morocco. Samples of mussels, clams and oysters were chosen as sentinel bivalve species due to their economic interest and conditions of life. The bivalve samples were then freeze-dried and crushed to determine the concentrations of organochlorine pesticides and polychlorinated biphenyl. The study confirms the occurrence of the main compounds of the organochlorine pesticides in Khnifiss Lagoon and cites atmospheric contamination as the possible reason for chlorinated compounds pollution in the lagoon.

The consumption of oysters and cockles, which are usually eaten raw or lightly-cooked, can cause outbreaks of human diseases, especially if these shellfish are harvested from polluted areas. In Brazil data about the occurrence of pathogens, like hepatitis A virus, in shellfish have been reported but research on natural contamination for pathogenic protozoa is still non-existent. Cryptosporidium oocyst contamination of oysters (Crassostrea rhizophorae) and cockles (Tivela mactroides) was evaluated during two different periods in a coastal area from Sã o Paulo, Brazil. From June to November 2005, and from July to December 2006, 180 mollusks were harvested for tissue examination. The gills and gastrointestinal tract (n = 36 pools) were carefully extracted from the animals and homogenized in a tissue homogenizer by adding surfactant Tween 80 (0.1%). Immunofluorescence assays were performed and Cryptosporidium oocysts were detected in 50.0% of gill pools of cockles and 10.0% of gill pools of oysters. In order to evaluate seawater quality in shellfish growing areas, total levels of thermotolerant coliforms, Escherichia coli and enterococci were determined. This is the first time that Cryptosporidium oocysts were found in shellfish from the coastal region of Brazil, and to the best of our knowledge it is also the first report in Latin America and the case might be of public health importance, reflecting the extension of the contamination on seafood, requiring a need for quality control standards. [ABSTRACT FROM AUTHOR]

The lethal and sublethal effects of the xenoestrogen 4-nonylphenol (NP) were evaluated in the cockle Cerastoderma glaucum. In a 96-h lethality test, bivalves were exposed to 0, 0+ acetone, 0.19, 0.38, 0.75, 1.5 and 3.0mg NP/l. The 96-h LC50 value was 0.3mg NP/l. No mortality was observed at 0.1mg NP/l. The potential estrogenicity of NP was studied in both sexually undifferentiated (resting phase) and differentiated (pre-spawning phase) cockles, exposed for 7 and 14days to 0, 0+ acetone, 0.0125, 0.025, 0.05, and 0.1mg NP/l. Vitellogenin (Vg)-like protein levels were determined in both haemolymph and digestive gland by the alkali-labile phosphate (ALP) assay. In the resting phase, exposure for 7days to 0.1mg NP/l resulted in significant increases in ALP in both haemolymph and digestive gland, compared with controls. A significant increase was also observed in digestive gland of animals exposed to 0.0125mg NP/l-exposed animals. After 14days of exposure, haemolymph ALP levels were significantly increased in exposed animals at all NP concentrations tested, whereas no difference was recorded in digestive gland. In the pre-spawning phase, exposure for 7days to NP significantly increased ALP levels in haemolymph from males exposed at all NP concentrations tested, whereas no significant variations were found in haemolymph from females. NP (0.05 and 0.1mg/l) was also shown to increase ALP concentrations significantly in digestive gland of males, but not in those of females. Likewise, after 14 days’ exposure, ALP levels significantly increased in haemolymph from males only at 0.1mg NP/l. Conversely, NP caused significant increases in ALP levels in digestive gland from both males (at all NP concentrations tested) and females (at 0.025 and 0.1mg NP/l). These results demonstrate that NP induces Vg synthesis in C. glaucum. Interestingly, males were more responsive to NP than females. [Copyright &y& Elsevier]

The in vivo effects of 4-nonylphenol (NP) on functional responses of haemocytes from the cockle Cerastoderma glaucum were investigated after 7 days exposure to sublethal NP concentrations (0, 0+acetone, 0.0125, 0.025, 0.05 and 0.1mg/lNP). Haemocytes from both controls and exposed cockles were collected, and the effects of NP on total haemocyte count (THC) and volume of circulating cells, intracellular superoxide anion () levels, acid phosphatase and lysozyme-like activities in both haemocyte lysate (HL) and cell-free haemolymph (CFH) were evaluated. Exposure of cockles to 0.1mg/lNP significantly increased THC (p <0.05) with respect to controls. Analysis of haemocyte size frequency distribution showed that the haemocyte fraction of about 7–8μm in diameter and 250femtolitres in volume increased markedly in cockles exposed to the highest NP concentration tested. Apoptosis resulting in cell volume reduction in NP-exposed animals cannot be excluded. No statistically significant variation in intracellular levels was observed. Conversely, significant increases (p <0.05) in acid phosphatase activity were observed in CFH from 0.05 and 0.1mg/l NP-exposed animals; no significant differences in enzyme activity were recorded in HL. Lysozyme-like activity also increased significantly in CFH from cockles exposed to 0.05mg/l NP (p <0.05) and 0.1mg/l NP (p <0.001). Instead, lysozyme-like activity decreased significantly (p <0.05) in the HL of animals exposed to 0.05mg/lNP. Our results suggest that NP induces variations in the functional responses of haemocytes of C. glaucum, mainly by reducing cell membrane stability and promoting cell degranulation. [Copyright &y& Elsevier]

Cockles (Anadara granosa) sample obtained from two rivers in the Penang State of Malaysia were analyzed for the content of arsenic (As) and heavy metals (Cr, Cd, Zn, Cu, Pb, and Hg) using a graphite flame atomic absorption spectrometer (GF-AAS) for Cr, Cd, Zn, Cu, Pb, As and cold vapor atomic absorption spectrometer (CV-AAS) for Hg. The two locations of interest with 20 sampling points of each location were Kuala Juru (Juru River) and Bukit Tambun (Jejawi River). Multivariate statistical techniques such as multivariate analysis of variance (MANOVA) and discriminant analysis (DA) were applied for analyzing the data. MANOVA showed a strong significant difference between the two rivers in term of As and heavy metals contents in cockles. DA gave the best result to identify the relative contribution for all parameters in discriminating (distinguishing) the two rivers. It provided an important data reduction as it used only two parameters (Zn and Cd) affording more than 72% correct assignations. Results indicated that the two rivers were different in terms of As and heavy metal contents in cockle, and the major difference was due to the contribution of Zn and Cd. A positive correlation was found between discriminate functions (DF) and Zn, Cd and Cr, whereas negative correlation was exhibited with other heavy metals. Therefore, DA allowed a reduction in the dimensionality of the data set, delineating a few indicator parameters responsible for large variations in heavy metals and arsenic content. Taking into account of these results, it can be suggested that a continuous monitoring of As and heavy metals in cockles be performed in these two rivers. [Copyright &y& Elsevier]

Perkinsus olseni infections are reported at 10%–84% prevalences among Austrovenus stutchburyi clams (cockles) in northern New Zealand coastal waters. However, P. olseni has not yet been propagated in vitro from New Zealand clams. In our sample of A. stutchburyi clams from Mangemangaroa Stream, New Zealand, 24% (8/34) showed low-intensity Perkinsus sp. infections among mantle and gill tissues incubated in alternative Ray's fluid thioglycollate medium (ARFTM), and 5% (4/79) showed Perkinsus sp. lesions by histological analyses. Among clams that were screened using a polymerase chain reaction (PCR) assay, 16% (3/19) were positive for Perkinsus sp. DNA. Alternative Ray's fluid thioglycollate medium-enlarged hypnospores from tissues of five infected clams yielded three in vitro Perkinsus sp. isolate cultures that were cloned before sequencing internal transcribed spacer (ITS) regions of their rRNA gene complex. For one isolate, ATCC PRA-205, large subunit (LSU) rRNA and actin genes were also sequenced. All nucleotide sequences from all isolates consistently identified them as P. olseni, as did their in vitro cell cycles and zoosporulation characteristics. All in vitro isolate cultures and their respective monoclonal derivative strains were cryopreserved and deposited for archiving and distribution by the American Type Culture Collection ( ). [ABSTRACT FROM AUTHOR]

Abstract: The main objectives of this study were: 1) to determine the influence of water currents on the suspension feeding rate of cockles (Cerastoderma edule); 2) to quantify the interaction between cockle feeding and flow on algal cell depletion in the overlying water column, and 3) to measure the effect of flow on resuspension of their pseudofaeces and faeces. Flume experiments demonstrated that suspension feeding rate (i.e. clearance rate) of C. edule was not significantly affected by increasing current speed, at least between 5 and 35 cm s−1. Measurement of vertical profiles in algal cell concentrations within the water column showed a marked depletion above the bed, and the size of this was inversely related to currents'' speeds below 5 cm s−1. At 2 cm s−1 the algal cell depletion was maximum immediately above the bed. However, below currents of 1 cm s−1 the maximum depletion was at 10 cm above the bed. This was a result of the exhalent jet of the cockle pumping filtered water (i.e. algal free) vertically into the water column and above the intake level of the inhalant siphon. Such stratification of the water column would appear to be beneficial to the cockle because it reduces the degree of re-filtration of algal cell depleted water at times of low flow, when there is poor mixing and thus poor replenishment of phytoplankton to the boundary layer. Critical erosion thresholds for cockle biodeposits, produced from a diet of silt and unicellular algae, were recorded at current velocities of 15 and 25 cm s−1, or shear velocities of 0.6 and 1.0 cm s−1, for pseudofaeces and faeces respectively. [Copyright &y& Elsevier]

Abstract: The content and distribution of n-alkane (C8–C35) and isoprenoid (pristane and phytane) hydrocarbons were investigated in two species of bivalve mollusk, mussel (Mytilus galloprovincialis) and cockle (Cerastoderma edule), collected at different points of the Galicia littoral zone during the period from December 2002 to February 2003 (after the Prestige oil spill). Samples were analyzed by high-resolution gas chromatography equipped with a flame ionization detector. The highest levels were found in mussels and cockles coming from two estuarine bays, Rías de Arousa and Vigo. Hydrocarbons with carbon chain length >30 were detected and determined in all samples. The abundance of these hydrocarbons in biota could be interpreted with regard to the feeding and living habits. Chemometric techniques have been employed to analyze data and determine the potential source of hydrocarbon contamination. Differences between mussels and cockles were observed in relation to aliphatic content. According to the data analysis, the main source of hydrocarbon contamination of investigated samples seems to be more related to the intense traffic of vessels in these estuarine bays than to the Prestige oil spill. [Copyright &y& Elsevier]

Abstract: This study aimed to determine the occurrence of Vibrio parahaemolyticus in cockles (Anadara granosa) at a harvesting area and to detect the presence of virulent strains carrying the thermostable direct hemolysin (tdh) and TDH-related hemolysin genes (trh) using PCR. Of 100 samples, 62 were positive for the presence of V. parahaemolyticus with an MPN (most probable number) value greater than 3.0 (>1100 MPN per g). The PCR analysis revealed 2 samples to be positive for the tdh gene and 11 to be positive for the trh gene. Hence, these results demonstrate the presence of pathogenic V. parahaemolyticus in cockles harvested in the study area and reveal the potential risk of illness associated with their consumption. [Copyright &y& Elsevier]

Relatively high E. coli and Faecal Streptococci (FS) numbers have been reported in the waters surrounding Blakeney Point, East Anglia, UK, an area containing significant shellfishery industries including mussels and cockles, despite the implementation of development works aimed at reducing residual contamination problems. The aim of this study was to evaluate the potential of using bacterial analyses and sterol profiling to assess the current levels and source of faecal pollution at Blakeney Point. No evidence of significant human faecal contamination of water in and around Blakeney Point could be found using either traditional microbiological analyses or sterol profile analysis. The presence of significant quantities of sitosterol, however, suggests that faecal contamination of water from birds does occur but at the concentration detected would not affect water quality. Analysis of cockles and mussels taken from the area show that negligible levels of coprostanol were present, confirming that faecal pollution was not causing any contamination issues. Apart from cholesterol, brassicasterol, an algal biomarker, as expected was dominant in shellfish flesh. The results confirm that current water treatment processes are successful in ensuring water quality at Blakeney Point and that a combination of microbial testing with sterol profile analysis confirmed that low microbial concentrations of faecal contaminants present in and around Blakeney Point most probably originate from migratory and/or resident bird species. [ABSTRACT FROM AUTHOR]