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This study, conducted between February 2016 and October 2017 on the coast of Erdek in the Marmara Sea, established two longline systems (buoy and pipe). Monthly growth rates of juvenile mussels placed in polyethylene and polyamide nets within these systems were monitored. The monthly chemical composition and meat yield of mussels that reached harvest size were analyzed in both systems. Environmental parameters were measured monthly to assess environmental conditions. The highest meat yield of harvested mussels was recorded in January, with values of 36.99 ± 0.72% for mussels cultured in the pipe system and 31.43 ± 1.82% for those cultured in the buoy system. The highest growth in mussels was achieved in the group cultured in the pipe system within polyamide nets. The December sample showed the highest moisture content of 83.98% and the highest ash content of 2.34%. The highest crude fat content was found in the September sample. The June sample had the highest protein content. The Black Sea, Sea of Marmara, and Aegean Sea offer suitable areas for mussel cultivation. Currently, mussel farming is conducted in these areas, producing tens of thousands of tons annually. This publication contributes to the expansion of the production process. [ABSTRACT FROM AUTHOR]

Global declines in marine shellfish have resulted in widespread efforts to restore populations. Previous research has predominantly focused on substrate‐limited rather than recruitment‐limited systems, yet given increased use of aquaculture‐produced stock to restore marine bivalves, there is a need to understand differences in the survival of hatchery‐produced and translocated wild stock. We conducted a systematic review and synthesis of studies that quantified the survival of outplanted marine bivalves.The systematic review identified 893 unique stocking events across 111 studies for 29 species across 10 families. Most research has occurred in temperate regions (73%), across four bivalve families (Ostreidae 37%, Pectinidae 20%, Veneridae 16% and Mytilidae 11%). More stockings have outplanted hatchery‐produced (66%) than translocated stock (34%).We conducted quantitative analyses for five species to determine how stock origin, size at outplant, outplant density, substrate co‐deployment, predator exclusion and time since outplant influences survival. Survival consistently decreased through time across all species. Substrate co‐deployment, stock origin and size at outplant did not influence survival, while predator exclusion and outplant density affected some species.Synthesis and applications. Our analyses broadly demonstrate variability in the survival of outplanted bivalves through time, however predicted survival was poor after 2 years (<3%). Generally low survival highlights difficulties associated with conducting scalable restoration in recruitment‐limited systems. Based on our findings, using hatchery‐produced stock, mitigating predation and outplanting epifaunal bivalves at high densities may increase survival probabilities when outplanting stock for restoration. Further exploration is needed to understand whether use of aquaculture‐produced stock results in similar ecosystem structure, function, and service provisioning to natural and restored shellfish reefs in recruitment‐limited systems. [ABSTRACT FROM AUTHOR]

The severity, frequency, and duration of extreme events, in the context of global warming, have placed many marine ecosystems at high risk. Therefore, the application of methods that can mediate the impacts of global warming on marine organisms seems to be an emerging necessity in the near term. In this context, enhancing the thermal resilience of marine organisms may be crucial for their sustainability. It has been shown that the repeated time-limited exposure of an organism to an environmental stimulus modifies its response mode, thus enhancing resilience and allowing adaptation of the physiological and developmental phenotype to environmental stress. In the present study, we investigated the "stress memory" effect caused by heat hardening on Mytilus galloprovincialis cellular pathways to identify the underlying biochemical mechanisms that enhance mussel thermal tolerance. Heat hardening resulted in increased ETS activity and ATP production and increased autophagic performance at all elevated temperatures (24 °C, 26 °C, and 28 °C). Furthermore, at these increased temperatures, apoptosis and inflammation remain at significantly lower levels in pregnant individuals than in nonhardened individuals. Autophagy, as a negative regulator of apoptosis, may lead to decreased damage to surrounding cells, which in turn alleviates inflammatory effects. In conclusion, the exposure of mussels to heat hardening seems to provide a physiological response that enhances heat tolerance and increases cell survival through increased energy production and reduced cell death and inflammatory responses. The latter can be utilized for the management and conservation of aquatic species of economic value or endangered status. [ABSTRACT FROM AUTHOR]

Practical Application Eating mussels contaminated with cadmium (Cd) can seriously harm health. In this study, a non‐destructive and rapid detection method for Cd‐contaminated mussels based on near‐infrared reflectance spectroscopy was studied. The spectral data of Cd‐contaminated and non‐contaminated mussels were collected in the range of 950–1700 nm. The model based on a robust energy‐based least squares twin support vector machine (RELS‐TSVM) was established to detect Cd‐contaminated mussels. The influence of parameters on the RELS‐TSVM model was analyzed, and the most suitable parameters were determined. The average accuracy of the proposed RELS‐TSVM model in detecting Cd‐contaminated mussels reached 99.92%, which was better than other twin support vector machine‐derived models. For test datasets with different kinds of spectral noises (Gaussian noise, baseline shift, stray light, and wavelength shift), the RELS‐TSVM model had a high robustness for noise disturbance. The results show that near‐infrared spectroscopy combined with the RELS‐TSVM model can realize the detection of Cd‐contaminated mussels, which can provide technical support for the monitoring of heavy metals in shellfish.The method of detecting Cd‐contaminated mussels by the NIRS has important practical significance for ensuring the safety of consumers. It provides a new way for the quality assessment and safety detection of shellfish and provides a technical basis for the marine environment assessment and management. [ABSTRACT FROM AUTHOR]

Parasites can alter the traits or densities of mutualistic partners, potentially destabilizing mutualistic associations that underpin the structure, functioning, and stability of entire ecosystems. Despite the potentially wide‐ranging consequences of such disruptions, no studies have directly manipulated parasite prevalence and/or intensity in a mutualistic partner, nor quantified the resulting community‐level effects. Here, we investigated the effects of a common trematode parasite (Cercaria opaca) on the strength of a keystone facultative mutualism in western Atlantic salt marshes between the foundational marsh cordgrass, Spartina alterniflora, and the ribbed mussel, Geukensia demissa. Cordgrass increases mussel survivorship and growth through shading, while mussels enhance cordgrass growth by producing nutrient‐rich biodeposits. This mutualistic association also creates conditions that enhance biodiversity and ecosystem functioning, and mediates the ability of foundational plants to resist and recover from extreme drought. We used lab and field assays to show how increasing infection with trematode metacercariae negatively influenced mussel biodeposit production, as well as the strength of mussel shells and byssal attachments. By conducting a field manipulation using experimentally infected mussels, we demonstrated that the mutualistic benefits of mussels to cordgrass growth decreased with increasing trematode infection intensity—a pattern likely generated by reduced mussel biodeposition and enhanced mortality. Additionally, increasing parasite loads in mussels led to predictable decreases in the abundances of benthic invertebrates, as well as in key ecosystem characteristics and process rates (i.e., redox potential and sediment accretion). Finally, a survey of five North Carolina salt marshes demonstrated that infection with C. opaca was most common in mussels in areas experiencing cordgrass die‐off due to drought, and that infection intensity decreased with distance from die‐off areas. Because the mussel–cordgrass mutualism underpins marsh ecosystem resilience to drought‐associated die‐off, our results suggest that parasitism may depress recovery from these disturbances. Although this is the first experimental demonstration of parasites indirectly altering community structure and functioning by undermining an ecologically influential mutualism, this type of relationship could be common in nature, given that parasites frequently infect influential mutualists. [ABSTRACT FROM AUTHOR]

Arcobacter-related species are considered emerging food-borne and waterborne pathogens, with shellfish being a suggested reservoir. In a published study that investigated 204 shellfish samples and 476 isolates, the species Arcobacter butzleri (now known as Aliarcobacter butzleri) and Arcobacter molluscorum (now known as Malaciobacter molluscorum) have been isolated as the most dominant species. However, the efficiency of depuration for eliminating A. butzleri and M. molluscorum in comparison with Escherichia coli from mussels and oysters is unknown and is therefore the objective of this investigation. The shellfish depuration process was evaluated in the laboratory, in summer and winter, using mussels and oysters collected from the Ebro Delta harvesting areas after performing a natural contamination and an artificial contamination using the same conditions for both mollusk and seasons. The natural contamination was performed by exposing the shellfish to a freshwater channel that receives untreated sewage from the village of Poble Nou (PNC) and that had a salinity of 10.7–16.8‰. The artificial contamination exposed the shellfish to A. butzleri and E. coli (in one tank) and to M. molluscorum and E. coli in another tank under controlled conditions of salinity (34.5‰) and temperature (20 °C summer and 14 °C winter). When evaluating the reduction in the bacteria load (every 24 h) throughout 120 h, the naturally contaminated shellfish at the PNC showed a higher reduction than the shellfish contaminated at the laboratory, with the exception of M. molluscorum, that at 24 h could not be detected in summer, neither in mussels nor in oysters. This may be attributed to the fact that the bacteria from the PNC were less adapted to the conditions of high salinity (34.5‰) in which the depuration process was performed. Although temperature did not statistically make a difference in depuration, at 20 °C a higher elimination of all bacteria was recorded relative to 14 °C. In general, E. coli survived more in mussels than in oysters, and M. molluscorum suffered in both mollusks a higher reduction than A. butzleri. New studies are required to determine further the safety of bivalves regarding the presence of Arcobacter-related species. [ABSTRACT FROM AUTHOR]

Farmed mussels accumulate contaminants from their production environment rather than releasing them into water. This study reveals potential health risks associated with selenium, cadmium, mercury, and lead resulting from the consumption of mussels (Mytilus galloprovincialis) cultured along the coasts of Türkiye and Bulgaria. The concentrations of Se and toxic trace metals were measured by inductively coupled plasma mass spectrometry (ICP-MS). The detection limits (LOD) were 0.100, 0.015, 0.025, and 0.180 µg/kg for Se, Cd, Hg, and Pb, respectively. The mean Se concentrations were between 1.305 and 1.957 µg/g, and toxic metals were below the maximum limits. Due to Turkish and Bulgarian consumers' limited mollusk consumption, mussels could only provide a maximum of 7.35% of the daily Se need. THQ and TTHQ of Se, Cd, and methyl-Hg were below 1, indicating that farmed mussels were safe for consumption. Percent PTWI values were calculated only for Cd and MeHg, as the PTWI value for Pb was discarded by the authorities and not determined for Se. Accordingly, weekly mussel consumption did not pose any risks. The margin of exposure approach was used to evaluate Pb intake. MOE-SBP and MOE-NE were significantly higher than 10, designating no significant health risks. Long-term consumption of mussels also does not pose a carcinogenic risk regarding the TR index calculated between 10−5 and 10−6 for Pb. Positive HBVSe (10.13–37.27) indicated that Se in mussels overcame Hg-related potential health concerns. Consequently, mussels grown in Türkiye and Bulgaria did not pose a risk for human consumption, based on current risk analysis methods. [ABSTRACT FROM AUTHOR]

Iodinated contrast media (ICMs) used in X-ray imaging for medical diagnostics are released into wastewater and then encountered in river water at concentrations ranging from several dozen to hundreds of µg/L, and even thousands of µg/L in hospital effluents. ICMs are considered as emerging pollutants as their occurrence and impact on ecosystems and the environment are poorly documented. Even if they are considered inert for humans, aquatic organisms are continuously exposed to ICMs, and their potential deleterious effects are therefore questioned as we have recently demonstrated that they enter into organisms such as the zebra mussels. To answer this question, Dreissena polymorpha were exposed to two ICMs of different osmolality, diatrizoic acid and iohexol, at an environmental concentration (100 µg/L) for 21 days before a depuration phase of 4 days. The occurrence, fate, and impact of both ICMs in these organisms were studied using a metallomic approach. Thus, iodine as well as endogenous copper and zinc were quantified and analyzed in cytosolic extracts of digestive glands, gills, and gonads of mussels by size exclusion chromatography coupled to ICP MS. This work shows that a subcellular fractionation is necessary to distinguish variations in total element content. The cytosolic iodoprotein chromatographic pattern was consistent for the three organs and confirmed the presence of ICMs in cytosols. Additionally, this exploratory work tends to show a weak biological effect of ICMs with a substantial variation of the profile of Cu-binding proteins mostly in the gill cytosol and to a lesser extent, in the digestive gland cytosol. [ABSTRACT FROM AUTHOR]

The effect of moderate (2 mg O2/L) and acute (1 mg O2/L) hypoxia on the state of the antioxidant complex of the mussel Mytilus galloprovincialis (Lamarck, 1819) has been studied. The activity of superoxiddismutase (SOD), catalase, and glutathione peroxidase (GP) in the hepatopancreas and gills of the mollusk is determined. The reactions of the AO complex of mussels to oxygen deficiency depend on the degree of hypoxic exposure and had tissue specificity. Acute hypoxia has a more pronounced effect on the mussel than moderate hypoxia. An increase in the activity of all the studied enzymes is observed in the gills of the mollusk under acute hypoxia. Under these conditions, only catalase activity increases in the hepatocreas of the mussel, and SOD significantly decreases. Under moderate hypoxia conditions, the AO protection of the mollusk gills is provided by SOD and GP, and in hepatopancreas, by activation of catalase and GP. These reactions indicate the development of moderate oxidative stress in mussel tissues under both hypoxia regimes. The features of the AO response of gills and hepatopancreas reflect their tissue-specific sensitivity to the effects of oxygen deficiency. [ABSTRACT FROM AUTHOR]

Nowadays, synthetic polymer (plastic) particles are ubiquitous in the environment. It is known that for several decades microplastics (MPs) have been accumulating in the World Ocean, becoming available to a large variety of marine organisms. Particularly alarming is the accumulation of aging plastic particles, as the degradation processes of such particles increase their toxicity. The diverse display of negative properties of aging MPs and its effect on biota are still poorly understood. In this study, in vitro experiments modeling the interaction of pristine and UV-irradiated aging polypropylene (PP) fragments with hemocytes and mitochondria of bivalve mollusks Mytilus sp. were performed. The appearance of free radicals in the environment was recorded by spectral characteristics of indicator dyes—methylene blue (MB) and nitroblue tetrazolium (NBT). It was found that due to photooxidation, aging PP fragments sorbed more than threefold MB on their modified surface compared to pristine samples of this polymer. Using NBT, the formation of reactive oxygen species in seawater in the presence of pristine and photoactivated PP was recorded. It was also found that photodegraded PP fragments largely stimulated the development of lipid peroxidation processes in mitochondrial membranes and reduced the stability of hemocyte lysosome membranes compared to pristine PP fragments. In general, the results obtained concretize and supplement with experimental data the previously stated hypothesis of toxicity of aging MPs. [ABSTRACT FROM AUTHOR]

Paralytic shellfish toxins (PSTs) pose significant ecological and food safety hazards in China and the world. Consequently, there is a global consensus to intensify safety monitoring of these toxins to safeguard consumers. In recent years, the occurrence of harmful algal blooms (known as "red tides") has increased due to human activities and climate change. The contamination risk posed by PSTs is a pressing concern. This problem poses significant ecological and food safety risks in China and the world, leading to a global consensus on strengthening the safety monitoring of PSTs to ensure consumer safety. Several countries and regions, including the European Union, the United States, and Canada, have established strict regulatory limits (800 μg STXeq/kg) for PSTs and implemented monitoring programs. Currently, the main methods for detecting and monitoring PSTs include enzyme-linked immunosorbent assay, mouse bioassay, high-performance liquid chromatography, and liquid chromatography-tandem mass spectrometry (LC-MS/MS). Among them, LC-MS/MS has gained international attention due to its high throughput and sensitivity, allowing detailed analysis of toxin profiles in contaminated shellfish. However, the complexity of aquatic food matrices often introduces interference during detection, affecting the accuracy and precision of the results. Using matrix reference materials as quality controls during the analysis can effectively mitigate the errors caused by matrix effects. In recent years, research has been conducted in China on the preparation techniques of matrix reference materials. However, existing techniques have limitations, such as unstable raw materials, limited toxin types, and lack of commercial production. There is still a lack of PST standard materials in China that possess traceability, certification, and physical specimens. To meet the quality control and validation needs for PST detection and analysis, and to enhance the regulation of shellfish quality and safety, the preparation of various PST matrix reference materials has become a top priority.In this study, six PST-producing algae species from four major Chinese coastal areas were compared as the raw material for toxin production: Alexandrium catenella (GY-H25), Gymnodinium catenatum (GY-H65), Alexandrium tamarense (GY-H31 and AT5-3), Alexandrium pacificum (TI0989), and Alexandrium minutum (GY-H46). Through three-step extended culture, all strains achieved mean cell densities ranging from 4.0 × 106 to 4.0 × 107 cells/L. Single cell toxin producing capacity was ordered from highest to lowest as GY-H46, GY-H31, AT5-3, GY-H25, GY-H65, and TI0989. After comparing the toxin production per cell, algal cell density, and toxin composition of the six strains, GY-H46, GY-H31, GY-H25, and GY-H65 were selected for the exposure experiments. These four species of toxic algae (up to 1.0 × 105 cells) were fed to mussels (Mytilus galloprovincialis) for 7 days under controlled conditions. The results demonstrated that the toxin composition of contaminated mussels clustered with those of the causative algae and may separate from one another significantly during the different accumulation phases. GY-H46, GY-H31, and GY-H25 showed consistent toxin profiles with those found in mussels, but varied in the proportions of individual toxin components. GY-H65 exhibited significant differences in toxin composition and proportions in mussels. We also detected a new conversion component (dcSTX) with a maximum proportion of 29.6%. The proportion of dcNEO increased from 1.9% to 13.2% in GY-H65 and mussels. In addition, a high proportion of conversion from C2 to C1 was observed in mussels fed GY-H25 and GY-H65. The mean accumulation rates of toxins from the four toxic algae species in mussels ranged from 39.7% to 83.1%, with the highest toxicity reaching (1, 151.0 ± 7.6) μg STXeq/kg in mussels. Individual exposure experiments with the four toxic algae species demonstrated that mussels are capable of accumulating multiple components and high levels of PSTs. Based on the above observations, the feeding ratios of the low- and high-density groups in the mixed exposure experiment were determined as 1∶1∶1 ∶4 and 1∶1.6∶2.4∶8 for GY-H25, GY-H65, GY-H31, and GY-H46, respectively. The total algae feeding amount per mussel per day was 3.5 × 104 cells in the low-density group and 2.6 × 105 cells in the high-density group. When examining the PST content in mussels from the two mixed exposure groups, it was observed that the mean accumulation conversion rates were comparable at 41.4% and 44.6%, which were lower than the theoretical rates of 48.7% and 47.5%, respectively. The overall toxicity of the low- and high-density groups was (535.0±5.6) and (2, 636.0±12.4) μg STXeq/kg, respectively. After mixed exposure, both experimental groups of mussels accumulated a total of 12 PST components (NEO, dcSTX, dcNEO, GTX1, GTX4, GTX2, GTX3, GTX5, dcGTX2, dcGTX3, C1, and C2).This study demonstrates that mixed exposure of mussels to four toxin-producing algae species, namely A. catenella, A. tamarense, G. catenatum, and A. minutum, can result in the stable and manageable presence of 12 PST components. This provides technical support for the preparation of matrix reference materials that can be used in industrial regulation and industry services. The development of a preparation technology for matrix reference materials with multiple PST components, which do not exceed international limits, holds promise for water quality monitoring and the assessment of marine pollution risks, and provides reference materials for theoretical studies on PSTs risk formation mechanisms.

This study, conducted between February 2016 and October 2017 on the coast of Erdek in the Marmara Sea, established two longline systems (buoy and pipe). Monthly growth rates of juvenile mussels placed in polyethylene and polyamide nets within these systems were monitored. The monthly chemical composition and meat yield of mussels that reached harvest size were analyzed in both systems. Environmental parameters were measured monthly to assess environmental conditions. The highest meat yield of harvested mussels was recorded in January, with values of 36.99 ± 0.72% for mussels cultured in the pipe system and 31.43 ± 1.82% for those cultured in the buoy system. The highest growth in mussels was achieved in the group cultured in the pipe system within polyamide nets. The December sample showed the highest moisture content of 83.98% and the highest ash content of 2.34%. The highest crude fat content was found in the September sample. The June sample had the highest protein content. The Black Sea, Sea of Marmara, and Aegean Sea offer suitable areas for mussel cultivation. Currently, mussel farming is conducted in these areas, producing tens of thousands of tons annually. This publication contributes to the expansion of the production process.

DCOIT (4,5-Dichloro-2-octylisothiazol-3(2H)-one) is a widely used antifouling biocide that emerged after the ban on tributyltin. It has been immobilized in nanostructured silica (SiNC–DCOIT) to reduce its hazard in maritime coatings. This study aimed to compare the bioaccumulation, trophic transfer, and biomagnification of DCOIT in its soluble and nanostructured forms on mussels Mytilus galloprovincialis, using three different uptake routes: aqueous exposure (i.e., contaminated seawater), dietary exposure (i.e., microalgae Tetraselmis chuii as a contaminated food), and both contaminated food and seawater. DCOIT was determined on water and tissues after 1, 3, and 24 h of uptake and after 72 h of depuration. Briefly, mussels were able to rapidly uptake and metabolize DCOIT and SiNC–DCOIT. Both compounds were non-bioaccumulative, as their bioconcentration and bioaccumulation factor values were lower than 2000. However, the predator–prey biomagnification factors indicated that both forms could be transferred across the trophic web. Therefore, while our findings provide further insight into the environmental risk assessment of DCOIT and SiNC–DCOIT, they do not rule out the possibility of long-term DCOIT bioaccumulation, particularly in areas with constant DCOIT influx. Further studies are thus needed using larger experimental designs and under continuous exposure scenarios to increase the sustainability of the innovative nanomaterial. [ABSTRACT FROM AUTHOR]

Recent evidence has demonstrated the unique properties of the innate immune system, known as innate immune memory, immune priming, or trained immunity. These properties have been described as the ability of the innate immune system to learn from previous microbial experiences, which improves survival after subsequent infection. In this review, we present the state of knowledge on trained immunity in invertebrates and provide a comprehensive overview of these capabilities in cultured marine molluscs, which are currently threatened by recurrent diseases. Studies have shown that exposure to environmental microbiota, pathogens, or derived elements, can provide a stronger response and protection against future infections. These studies highlight common and distinct features of protection, mechanisms, specificity, and duration that vary with immune markers, and methods of stimulation. While the cellular and molecular basis of these responses is only partially understood, effects on phagocytosis, haemocyte populations, apoptosis, oxidative stress, and immune gene expression have been suggested. Finally, we propose a framework for future research to go beyond the current evidence and address potential limitations in the implementation of trained immunity‐based strategies to control disease. Immune training may provide a unique opportunity to promote the sustainable development of marine mollusc aquaculture. [ABSTRACT FROM AUTHOR]

Plastic pollution of marine environments has become a global problem. Microplastics have the potential to bioaccumulate in marine biota and ecosystems. Depending on their bioavailability and size, they can be potentially dangerous to the health of organisms and ecosystems. This study aimed to assess microplastics bioaccumulation in bivalve species from the hypereutrophic Varna Lake. Totally, 58 bivalves of three species (Mya arenaria, Mytilus galloprovincialis and Cerastroderma glaucum) were collected from Varna Lake. The most common type of microplastics were fragments (61.54%) followed by fibres (15.38%), microbeads (11.54%), films and sponge/foam. Microplastics were recovered in 60 % of M. galloprovincialis (1.73±2.09 part/ind.), 58 % of M. arenaria (1.77±2.27 part/ind.), and 29 % of C. glaucum (0.35±0.61 part/ind.). The lowest number of microplastics was identified in C. glaucum (0-2 part/ind.) while M. galloprovincialis (0-6 part/ind.) and M. arenaria (0-8 part/ind.) presented almost equal content. The most frequent plastic colour was blue (26.92 %) followed by red (25.64 %), grey (15.38 %), black (12.82 %) and green (10.26 %). Our study reveals the first evaluation of the uptake, level of accumulation, shape, colour and size class of microplastics by three native bivalve species in Varna Lake. Much more research is needed for a more precise assessment of the patterns of bioaccumulation and the effects of microplastics in marine bivalves. [ABSTRACT FROM AUTHOR]

Paralytic shellfish toxins (PSTs) are potent neurotoxins produced by certain microalgae, particularly dinoflagellates, and they can accumulate in shellfish in coastal seawater and thus pose significant health risks to humans. To explore the relationship between toxicity and PST profiles in seawater and mussels, the spatiotemporal variations in PST concentrations and profiles were investigated along the southern coast of Korea under peak PST levels during spring. Seawater and mussel samples were collected biweekly from multiple stations, and the toxin concentrations in the samples were measured. Moreover, the dinoflagellate community composition was analyzed using next-generation sequencing to identify potential PST-producing species. The PST concentrations and toxin profiles showed substantial spatiotemporal variability, with GTX1 and GTX4 representing the dominant toxins in both samples, and C1/2 tending to be higher in seawater. Alexandrium species were identified as the primary sources of PSTs. Environmental factors such as water temperature and salinity influenced PST production. This study demonstrates that variability in the amount and composition of PSTs is due to intricate ecological interactions. To mitigate shellfish poisoning, continuous monitoring must be conducted to gain a deeper understanding of these interactions. [ABSTRACT FROM AUTHOR]

The smooth-shelled blue mussel, Mytilus edulis is part of the Mytilus species complex, encompassing at least three putative species: M. edulis, Mytilus galloprovincialis , and Mytilus trossulus. These three species occur on both sides of the Atlantic and hybridize in nature, and both M. edulis and M. galloprovincialis are important aquaculture species. They are also invasive species in many parts of the world. Here, we present a chromosome-level assembly of M. edulis. We used a combination of PacBio sequencing and Dovetail's Omni-C technology to generate an assembly with 14 long scaffolds containing 94% of the predicted length of the M. edulis genome (1.6 out of 1.7 Gb). Assembly statistics were as follows: total length = 1.65 Gb, N50 = 116 Mb, L50 = 7, and L90 = 13. BUSCO analysis showed 92.55% eukaryote BUSCOs identified. AB- Initio annotation using RNA-seq from mantle, gills, muscle, and foot predicted 47,128 genes. These gene models were combined with IsoSeq validation resulting in 45,379 full CDS protein sequences and 129,708 isoforms. Using GBS and shotgun sequencing, we also sequenced several eastern Canadian populations of Mytilus to characterize single-nucleotide as well as structural variance. This high-quality genome for M. edulis provides a platform to develop tools that can be used in breeding, molecular ecology and evolution to address questions of both commercial and environmental perspectives. [ABSTRACT FROM AUTHOR]

In February 2023, a severe cold snap took place in Atlantic Canada and was followed by the mass loss of mussels at mid-to-high intertidal elevations on the southeastern Nova Scotia coast. This loss was concerning because mussels sustain upper trophic levels in coastal food webs and because mussel stands enhance local biodiversity by sheltering many small invertebrate species. Using photographs taken in the second summer after that cold snap (July 2024), this article provides visual evidence of active ongoing recolonization of intertidal mussels on this coast, including the incipient formation of new stands. These are encouraging signs of ecological resilience. Reaching historical values of abundance will likely depend on the future occurrence of weather extremes, which are becoming more frequent with the ongoing climate change. [ABSTRACT FROM AUTHOR]

In the early summer of 2021, an intense heatwave killed millions of intertidal mussels in British Columbia, Canada. Using photographs taken three years later (June 2024), this article provides visual evidence of active recovery of intertidal mussel stands in the Vancouver region, revealing the resilience of these intertidal systems. Future monitoring should evaluate their ability for long-term persistence in light of the ongoing climate change, which is expected to increase the frequency and intensity of heatwaves. [ABSTRACT FROM AUTHOR]

Rocky intertidal habitats occur worldwide and are mainly characterized by primary space holders such as seaweeds and sessile invertebrates. Some of these organisms are foundation species, as they can form structurally complex stands that host many small invertebrates. The abundance of primary space holders is known to vary along coastlines driven directly or indirectly by environmental variation. However, it is less clear if the invertebrate assemblages associated to a foundation species may remain relatively unchanged along coastlines, as similar stands of a foundation species can generate similar microclimates. We examined this question using abundance data for invertebrate species found in mussel stands of a similar structure in wave-exposed rocky habitats at mid-intertidal elevations along the Atlantic coast of Nova Scotia (Canada). While the most abundant invertebrate species were found at three locations spanning 315 km of coastline, species composition (a combined measure of species identity and their relative abundance) differed significantly among the locations. One of the species explaining the highest amount of variation among locations (a barnacle) exhibited potential signs of bottom-up regulation involving pelagic food supply, suggesting benthic–pelagic coupling. The abundance of the species that explained the highest amount of variation (an oligochaete) was positively related to the abundance of their predators (mites), further suggesting bottom-up forcing in these communities. Overall, we conclude that species assemblages associated to structurally similar stands of a foundation species can show clear changes in species composition at a regional scale. [ABSTRACT FROM AUTHOR]

Our study focused exclusively on analyzing Escherichia coli (E. coli) contamination in fresh raw mussels and ready-to-eat (RTE) stuffed mussels obtained from authorized and regulated facilities. However, it is critical to recognize that such contamination represents a significant public health threat in regions where unauthorized harvesting and sales practices are prevalent. This study aimed to comprehensively assess the prevalence, molecular characteristics, and antibacterial resistance profiles of E. coli in fresh raw mussels and RTE stuffed mussels. E. coli counts in fresh raw mussel samples ranged from 1 to 2.89 log CFU/g before cooking, with a significant reduction observed post-cooking. RTE stuffed mussel samples predominantly exhibited negligible E. coli presence (<1 log CFU/g). A phylogenetic analysis revealed a dominance of phylogroup A, with variations in the distribution observed across different sampling months. Antibacterial resistance was prevalent among the E. coli isolates, notably showing resistance to ampicillin, streptomycin, and cefotaxime. Extended-spectrum β-lactamase (ESβL) production was rare, with only one positive isolate detected. A variety of antibacterial resistance genes, including tetB and sul1, were identified among the isolates. Notably, virulence factor genes associated with pathogenicity were absent. In light of these findings, it is imperative to maintain rigorous compliance with quality and safety standards at all stages of the mussel production process, encompassing harvesting, processing, cooking, and consumption. Continuous monitoring, implementation of rigorous hygiene protocols, and responsible antibacterial drug use are crucial measures in mitigating food safety risks and combating antibacterial resistance. Stakeholders, including seafood industry players, regulatory agencies, and healthcare professionals, are essential to ensure effective risk mitigation and safeguard public health in the context of seafood consumption. [ABSTRACT FROM AUTHOR]

Human impacts on ecosystems are resulting in unprecedented rates of biodiversity loss worldwide. The loss of species results in the loss of the multiple roles that each species plays or functions (i.e., ecosystem multifunctionality) that it provides. A more comprehensive understanding of the effects of species on ecosystem multifunctionality is necessary for assessing the ecological impacts of species loss. We studied the effects of two dominant intertidal species, a primary producer (the seaweed Neorhodomela oregona) and a consumer (the shellfish Mytilus trossulus), on 12 ecosystem functions in a coastal ecosystem, both in undisturbed tide pools and following the removal of the dominant producer. We modified analytical methods used in biodiversity-multifunctionality studies to investigate the potential effects of individual dominant species on ecosystem function. The effects of the two dominant species from different trophic levels tended to differ in directionality (+/-) consistently (92% of the time) across the 12 individual functions considered. Using averaging and multiple threshold approaches, we found that the dominant consumer-but not the dominant producer-was associated with ecosystem multifunctionality. Additionally, the relationship between abundance and multifunctionality differed depending on whether the dominant producer was present, with a negative relationship between the dominant consumer and ecosystem function with the dominant producer present compared to a non-significant, positive trend where the producer had been removed. Our findings suggest that interactions among dominant species can drive ecosystem function. The results of this study highlight the utility of methods previously used in biodiversity-focused research for studying functional contributions of individual species, as well as the importance of species abundance and identity in driving ecosystem multifunctionality, in the context of species loss.

Predators affect their prey through consumptive and non-consumptive effects (NCEs). Regarding marine NCEs, predator chemical cues (e.g., exudates) can trigger various anti-predator responses in prey that can vary in magnitude according to the intensity of the perceived cues. Specimens of the mussel Perumytilus purpuratus were exposed to seawater that held different densities of the predatory snail Acanthina monodon as a proxy for predator cue intensity. The response of mussels was quantified in terms of valve gape size (VGS), clearance rate (CR), and oxygen consumption rate (OCR). The results showed that mussels reduced VGS, CR, and OCR as a function of the intensity of the predator exudates to which they were exposed. These results suggest that mussels are not only able to detect predators through their chemical exudates but can also detect the intensity of the predatory signal and thus respond physiologically (CR, OCR) and behaviorally (VGS) in accordance to the potential predation risk. These responses may have cascading effects at the community level, given that mussels are foundation species. [ABSTRACT FROM AUTHOR]

Bisphenols and phthalates are wide classes of endocrine disrupting chemicals (EDCs) extensively used as additives in plastic products. In this study, a fast and reliable analytical method based on matrix solid-phase dispersion (MSPD) coupled with LC-MS/MS was developed and optimized for simultaneous determination of 8 bisphenols and 7 phthalates in raw mussel extract. The LC-MS/MS method was tested for linearity (R2), inter- and intra-day repeatability, limit of detection and quantification, both for matrix-free and matrix-matched solutions. The MSPD method was optimized in terms of ratio between sample and sorbent, and the type and quantity of the eluents in order to maximize the recoveries and to minimize matrix effects. The obtained recoveries (values between 75% and 113%), limits of detection (values between 0.048 and 0.36 µg kg−1), limits of quantification (values between 0.16 and 1.28 µg kg−1), repeatability (RSD% between 1.30% and 8.41%) and linearity (R2 > 0.998) were satisfactory and suitable for the determination of target micropollutants in food samples. In addition, the low solvent consumption and fast execution make this method ideal for routinely determinations of bisphenols and phthalates in mussels. [ABSTRACT FROM AUTHOR]

Foundation species that modify their habitat can facilitate other species, including other foundation species. Most studies focus solely on a single foundation species, overlooking such facilitation cascades. In this study, we investigated the interactions between the two coastal foundation species Mytilus edulis (blue mussel) and Lanice conchilega (sand mason worm). We investigated whether these species engage in facilitative interactions or if their association simply reflects a shared ecological niche on the soft-sediment intertidal flats of the Dutch Wadden Sea. To do so, we performed species distribution modeling, manipulative field experiments, and field surveys. We found a positive association between both foundation species, with a 2.45 times higher occurrence of both species compared to a random distribution. In addition, these species partially occupied the same ecological niche. We demonstrated that L. conchilega provided settlement substrate for M. edulis spat, increasing densities by 400 times compared to bare plots. Furthermore, M. edulis reefs facilitated L. conchilega occurrence in the wake of the reef. Biogenic reef development revealed that this interspecific facilitation resulted in spatial habitat heterogeneity. Therefore, we conclude that interspecific facilitation can significantly enhance the occurrence of these two important intertidal foundation species. Acknowledgment of such complex facilitation interactions has an untapped potential for improving the success of restoration and conservation programs. [ABSTRACT FROM AUTHOR]

Research on the microbiota associated with marine invertebrates is important for understanding host physiology and the relationship between the host and the environment. In this study, the microbiota of the green mussel Perna viridis was characterized at the tissue scale using 16S rRNA gene high-throughput sequencing and compared with the microbiota of the surrounding environment. Different mussel tissues were sampled, along with two environmental samples (the mussel's attachment substratum and seawater). The results showed that the phyla Proteobacteria, Bacteroidetes, and Spirochaetae were dominant in mussel tissues. The bacterial community composition at the family level varied among the tissues of P. viridis. Although the microbiota of P. viridis clearly differed from that of the surrounding seawater, the composition and diversity of the microbial community of the foot and outer shell surface were similar to those of the substratum, indicating their close relationship with the substratum. KEGG prediction analysis indicated that the bacteria harbored by P. viridis were enriched in the degradation of aromatic compounds, osmoregulation, and carbohydrate oxidation and fermentation, processes that may be important in P. viridis physiology. Our study provides new insights into the tissue-scale characteristics of mussel microbiomes and the intricate connection between mussels and their environment. [ABSTRACT FROM AUTHOR]

Marine mussels can adhere to various surfaces in a liquid environment by utilizing pedicle filaments, with the adhesive properties primarily attributed to the structure of catechol, the main component of the filament. To overcome the challenges associated with the complex preparation process, high cost, and potential biological rejection of naturally extracted or recombinantly expressed mussel proteins, researchers drew inspiration from mussels and utilized an oxidative crosslinking approach to prepare adhesive hydrogel materials. However, the hydrogels prepared using this method exhibited inferior mechanical properties and low viscosity. To address these limitations, in this study, a kind of mussel-inspired dual-crosslinked hydrogel was prepared by dual cross-linking with hydroxypropyl chitosan (HPCS) and hyaluronic acid (HA), based on catechol, an adhesion component in marine mussel pedicle filaments. Comparative analysis revealed that the mussel-inspired dual-crosslinked hydrogel exhibited significantly higher adhesion strength (up to 33.96 kPa) and improved mechanical properties (energy storage modulus ranging from 489 to 1032 Pa) compared to the mussel-inspired oxidatively cross-linked hydrogel. In addition, the mussel-inspired dual-crosslinked hydrogel demonstrated favorable swelling (up to 136.54 ± 0.22%), degradation, sustained-release, bacteriostatic and biocompatible properties. These findings suggest a promising potential for future applications in the field of biomedical materials. [ABSTRACT FROM AUTHOR]

Foundation species are spatially dominant species that increase habitat complexity and provide substrate and shelter for many smaller species. Through a mensurative field experiment, we tested the hypothesis that functional aspects of the associated communities are related to structural and functional properties of the foundation species. Specifically, we contrasted invertebrate communities living in mussel (Mytilus) and seaweed (Chondrus) stands from the same rocky intertidal environments in Atlantic Canada. Both stands reach similar heights above the substrate, but they differ structurally (rigid mussel shells vs. flexible seaweed fronds) and functionally (mussels generate biowaste while seaweeds offer food for herbivores). Our data supported the hypothesis in various ways. Detritivory (mostly by oligochaetes) was more prevalent in mussel stands, while herbivory was more prevalent in seaweed stands. Predators were mostly mites and, consequently, they were more prevalent in mussel stands, as mites eat oligochaetes. Functional traits related to body and mobility types were also related to properties of the foundation species. Overall, we conclude that structural and functional properties of foundation species can predict functional aspects of the associated communities. This concept may help to develop effective restoration strategies after the loss of foundation species due to anthropogenic factors. [ABSTRACT FROM AUTHOR]

Rocky intertidal habitats occur worldwide and are mainly characterized by primary space holders such as seaweeds and sessile invertebrates. Some of these organisms are foundation species, as they can form structurally complex stands that host many small invertebrates. The abundance of primary space holders is known to vary along coastlines driven directly or indirectly by environmental variation. However, it is less clear if the invertebrate assemblages associated to a foundation species may remain relatively unchanged along coastlines, as similar stands of a foundation species can generate similar microclimates. We examined this question using abundance data for invertebrate species found in mussel stands of a similar structure in wave-exposed rocky habitats at mid-intertidal elevations along the Atlantic coast of Nova Scotia (Canada). While the most abundant invertebrate species were found at three locations spanning 315 km of coastline, species composition (a combined measure of species identity and their relative abundance) differed significantly among the locations. One of the species explaining the highest amount of variation among locations (a barnacle) exhibited potential signs of bottom-up regulation involving pelagic food supply, suggesting benthic–pelagic coupling. The abundance of the species that explained the highest amount of variation (an oligochaete) was positively related to the abundance of their predators (mites), further suggesting bottom-up forcing in these communities. Overall, we conclude that species assemblages associated to structurally similar stands of a foundation species can show clear changes in species composition at a regional scale.

Arcobacter-related species are considered emerging food-borne and waterborne pathogens, with shellfish being a suggested reservoir. In a published study that investigated 204 shellfish samples and 476 isolates, the species Arcobacter butzleri (now known as Aliarcobacter butzleri) and Arcobacter molluscorum (now known as Malaciobacter molluscorum) have been isolated as the most dominant species. However, the efficiency of depuration for eliminating A. butzleri and M. molluscorum in comparison with Escherichia coli from mussels and oysters is unknown and is therefore the objective of this investigation. The shellfish depuration process was evaluated in the laboratory, in summer and winter, using mussels and oysters collected from the Ebro Delta harvesting areas after performing a natural contamination and an artificial contamination using the same conditions for both mollusk and seasons. The natural contamination was performed by exposing the shellfish to a freshwater channel that receives untreated sewage from the village of Poble Nou (PNC) and that had a salinity of 10.7–16.8‰. The artificial contamination exposed the shellfish to A. butzleri and E. coli (in one tank) and to M. molluscorum and E. coli in another tank under controlled conditions of salinity (34.5‰) and temperature (20 °C summer and 14 °C winter). When evaluating the reduction in the bacteria load (every 24 h) throughout 120 h, the naturally contaminated shellfish at the PNC showed a higher reduction than the shellfish contaminated at the laboratory, with the exception of M. molluscorum, that at 24 h could not be detected in summer, neither in mussels nor in oysters. This may be attributed to the fact that the bacteria from the PNC were less adapted to the conditions of high salinity (34.5‰) in which the depuration process was performed. Although temperature did not statistically make a difference in depuration, at 20 °C a higher elimination of all bacteria was recorded relative to 14 °C. In general, E. coli survived more in mussels than in oysters, and M. molluscorum suffered in both mollusks a higher reduction than A. butzleri. New studies are required to determine further the safety of bivalves regarding the presence of Arcobacter-related species.

Nowadays, synthetic polymer (plastic) particles are ubiquitous in the environment. It is known that for several decades microplastics (MPs) have been accumulating in the World Ocean, becoming available to a large variety of marine organisms. Particularly alarming is the accumulation of aging plastic particles, as the degradation processes of such particles increase their toxicity. The diverse display of negative properties of aging MPs and its effect on biota are still poorly understood. In this study, in vitro experiments modeling the interaction of pristine and UV-irradiated aging polypropylene (PP) fragments with hemocytes and mitochondria of bivalve mollusks Mytilus sp. were performed. The appearance of free radicals in the environment was recorded by spectral characteristics of indicator dyes—methylene blue (MB) and nitroblue tetrazolium (NBT). It was found that due to photooxidation, aging PP fragments sorbed more than threefold MB on their modified surface compared to pristine samples of this polymer. Using NBT, the formation of reactive oxygen species in seawater in the presence of pristine and photoactivated PP was recorded. It was also found that photodegraded PP fragments largely stimulated the development of lipid peroxidation processes in mitochondrial membranes and reduced the stability of hemocyte lysosome membranes compared to pristine PP fragments. In general, the results obtained concretize and supplement with experimental data the previously stated hypothesis of toxicity of aging MPs.

Abstract This study was carried out with the freshwater mussel Unio tigridis exposed to lead nitrate. The samples of water and mussels were collected from Qandil water resources situated in Qandil village at 36° 37' 39.55" north latitude and 44° 10' 51.80" east longitude, and it is 322 meters above sea level. In January 2022, rivers and aquariums water were tested for temperature, pH, EC, TDS, DO, total alkalinity, total hardness, and calcium and magnesium ions. Studied organisms were exposed to variable concentrations of lead nitrate ranging from 0 to 900 ppm. The 96-h median lethal concentration (LC50) was measured and a comparison was made between the behavioural responses of the control and treatment groups. Also, the concentrations of lead in the experimental media, shell, and soft tissue of mussels were measured. A sample of mussels collected from aquarium was tested for biochemical markers, including acetylcholinesterase (AChE), Glutathione S-Transferase (GST), Catalase (CAT) and malondialdehyde (MDA). After 96 hours, the LC50 was estimated to be 782.7 ppm. The findings on behaviours revealed that lead slows down species' activities. Lead concentratiom increased within the mussel body as the water lead level decreased. The value of AChE was inversely related to lead concentration. However, GST, CAT and MDA increased with lead exposure. [ABSTRACT FROM AUTHOR]

Deep-sea mining activities can potentially release metals, which pose a toxicological threat to deep-sea ecosystems. Nevertheless, due to the remoteness and inaccessibility of the deep-sea biosphere, there is insufficient knowledge about the impact of metal exposure on its inhabitants. In this study, deep-sea mussel Gigantidas platifrons, a commonly used deep-sea toxicology model organism, was exposed to manganese (100, 1 000 µg/L) or iron (500, 5 000 µg/L) for 7 d, respectively. Manganese and iron were chosen for their high levels of occurrence within deep-sea deposits. Metal accumulation and a battery of biochemical biomarkers that related to antioxidative stress in superoxide dismutase (SOD), catalase (CAT), malondialdehyde (MDA); immune function in alkaline phosphatase (AKP), acid phosphatase (ACP); and energy metabolism in pyruvate kinase (PK) and hexokinase (HK) were assessed in mussel gills. Results showed that deep-sea mussel G. platifrons exhibited high capacity to accumulate Mn/Fe. In addition, most tested biochemical parameters were altered by metal exposure, demonstrating that metals could induce oxidative stress, suppress the immune system, and affect energy metabolism of deep-sea mussels. The integrated biomarker response (IBR) approach indicated that the exposure to Mn/Fe had a negative impact on deep-sea mussels, and Mn demonstrated a more harmful impact on deep-sea mussels than Fe. Additionally, SOD and CAT biomarkers had the greatest impact on IBR values in Mn treatments, while ACP and HK were most influential for the low- and high-dose Fe groups, respectively. This study represents the first application of the IBR approach to evaluate the toxicity of metals on deep-sea fauna and serves as a crucial framework for risk assessment of deep-sea mining-associated metal exposure. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Hydrobiology is the property of Editorial Department of Journal of Hydrobiology and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Artificial structures are often used as a tool for habitat restoration and the recreation of degraded coastal ecosystems and their associated food webs. However, it is often unknown if and how these artificial structures may influence the habitat use of target species, thereby hampering restoration goals. In this study, we test how artificial barriers, deployed to enhance the creation of an intertidal mussel bed, influenced the mussel‐habitat use by two bird species under pressure, Eurasian oystercatchers and Eurasian curlews. Average bird presence was monitored using time‐lapse camera's from the start of the mussel bed restoration in August 2018 until April 2019. We found that in the first few months of the experiment, both oystercatchers and curlews avoided the restored mussel beds containing artificial structures in the form of metal barriers that act as traps for dislodged mussels. Thereafter, the presence of barriers had no negative influence on the average presence of oystercatchers or curlews. In fact, curlews were significantly attracted to the mussel beds with barriers in January and February. In addition, we found a negative effect of the presence of European herring gulls on the presence of oystercatchers and curlews. The higher herring gull densities in the first 2 months of the experiment might explain the lower‐than‐expected curlew and oystercatcher densities observed in August. To our knowledge, no other studies have investigated the effect of artificial restoration structures on the abundance or habitat use of specific shorebirds. [ABSTRACT FROM AUTHOR]

Copyright of Baghdad Science Journal is the property of Republic of Iraq Ministry of Higher Education & Scientific Research (MOHESR) and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

ABSTRACT The present study aimed to analyze the parasite prevalence of 40 Perna Perna mussels (Linnaeus, 1758), to verify the presence of the parasite of the genus Bucephalus, originating from mariculture in the coastal lowlands, Rio de Janeiro, Brazil. Collections were made in the four seasons of the year (autumn, winter, spring, and summer), every three months, from March 2019 to February 2020. In microscopic analysis of soft tissue of P. perna, a prevalence rate of 22.5%parasite was found. Comparison of the two collection areas showed a higher prevalence in Praia do Forno, Arraial do Cabo, during autumn, and both male and female individuals affected.

In this study, a new method has been optimized to determinate nine bisphenols (BPs) in mussel samples. This approach is based on miniaturized matrix solid-phase dispersion combined with gas chromatography-mass spectrometry determination after trimethylsilylation with 99% N,O-Bis-(trimethylsilyl)trifluoroacetamide + 1 % trimethylchlorosilane. The optimization process investigated the derivatization (derivatizing agent volume, time and temperature) and sample preparation (C18 co-column packed and C18 dispersant agent amounts and elution volume) parameters. A second clean-up step was performed using EMR-Lipid cartridges in order to efficiently remove lipids from mussel, the optimized parameters were Captiva EMR-Lipid sorbent amount and elution volume. The whole method was validated and very good linearity (r2 > 0.99) was obtained. The recoveries (accuracy) at two concentration levels ranged from 51.2 to 109 % and the coefficients of variation (precision) were between 0.55 and 13 %. The limits of quantification were between 0.014 μg/Kg dry weight for BPM and 4.0 μg/Kg dry weight for BPS. The analytical procedure was applied to four mussel samples from Galician Rías. Except for one of four samples whose BPAF level was below the limit of quantification, all BPs were found in concentrations that ranged from 0.39 to 301 μg/Kg dry weight.

Foundation species that modify their habitat can facilitate other species, including other foundation species. Most studies focus solely on a single foundation species, overlooking such facilitation cascades. In this study, we investigated the interactions between the two coastal foundation species Mytilus edulis (blue mussel) and Lanice conchilega (sand mason worm). We investigated whether these species engage in facilitative interactions or if their association simply reflects a shared ecological niche on the soft-sediment intertidal flats of the Dutch Wadden Sea. To do so, we performed species distribution modeling, manipulative field experiments, and field surveys. We found a positive association between both foundation species, with a 2.45 times higher occurrence of both species compared to a random distribution. In addition, these species partially occupied the same ecological niche. We demonstrated that L. conchilega provided settlement substrate for M. edulis spat, increasing densities by 400 times compared to bare plots. Furthermore, M. edulis reefs facilitated L. conchilega occurrence in the wake of the reef. Biogenic reef development revealed that this interspecific facilitation resulted in spatial habitat heterogeneity. Therefore, we conclude that interspecific facilitation can significantly enhance the occurrence of these two important intertidal foundation species. Acknowledgment of such complex facilitation interactions has an untapped potential for improving the success of restoration and conservation programs.

In February 2023, a severe cold snap took place in Atlantic Canada and was followed by the mass loss of mussels at mid-to-high intertidal elevations on the southeastern Nova Scotia coast. This loss was concerning because mussels sustain upper trophic levels in coastal food webs and because mussel stands enhance local biodiversity by sheltering many small invertebrate species. Using photographs taken in the second summer after that cold snap (July 2024), this article provides visual evidence of active ongoing recolonization of intertidal mussels on this coast, including the incipient formation of new stands. These are encouraging signs of ecological resilience. Reaching historical values of abundance will likely depend on the future occurrence of weather extremes, which are becoming more frequent with the ongoing climate change.

Paralytic shellfish toxins (PSTs) are potent neurotoxins produced by certain microalgae, particularly dinoflagellates, and they can accumulate in shellfish in coastal seawater and thus pose significant health risks to humans. To explore the relationship between toxicity and PST profiles in seawater and mussels, the spatiotemporal variations in PST concentrations and profiles were investigated along the southern coast of Korea under peak PST levels during spring. Seawater and mussel samples were collected biweekly from multiple stations, and the toxin concentrations in the samples were measured. Moreover, the dinoflagellate community composition was analyzed using next-generation sequencing to identify potential PST-producing species. The PST concentrations and toxin profiles showed substantial spatiotemporal variability, with GTX1 and GTX4 representing the dominant toxins in both samples, and C1/2 tending to be higher in seawater. Alexandrium species were identified as the primary sources of PSTs. Environmental factors such as water temperature and salinity influenced PST production. This study demonstrates that variability in the amount and composition of PSTs is due to intricate ecological interactions. To mitigate shellfish poisoning, continuous monitoring must be conducted to gain a deeper understanding of these interactions.

In the early summer of 2021, an intense heatwave killed millions of intertidal mussels in British Columbia, Canada. Using photographs taken three years later (June 2024), this article provides visual evidence of active recovery of intertidal mussel stands in the Vancouver region, revealing the resilience of these intertidal systems. Future monitoring should evaluate their ability for long-term persistence in light of the ongoing climate change, which is expected to increase the frequency and intensity of heatwaves.

ObjectivesThe present study aimed to explore the preventive effect of mussel oil (MO) on atherosclerosis and the potential mechanism in apolipoprotein E-null (ApoE−/−) mice.MethodsApoE−/− mice were fed with a high-fat and high-cholesterol chow and given corn oil (CO), fish oil (FO), MO, or aspirin (ASP, dissolved in CO) by gavage for 12 weeks. The total n-3 polyunsaturated fatty acids (PUFAs) in MO (51.01%) and FO (46.82%) were comparable (mainly C22:6n-3 and C20:5n-3). Wild-type mice were fed with a normal chow and given equivalent CO as health control (CON).ResultsCompared with the CON group, obvious atherosclerotic plaque appeared at aorta and aortic sinus in the CO group. Compared with the CO group, MO but not FO had a significantly smaller atherosclerotic plaque area in the aorta. The aortic atherosclerotic plaque area was comparable in the MO, CON, and ASP groups. The MO group had a significantly smaller atherosclerotic plaque area, lower lipid deposition, lower contents of smooth muscle cell (SMC), and slightly lower contents of macrophage at the aortic sinus than the FO group. Serum concentrations of IL-1β, NF-κB, and VCAM-1 were comparable in the MO and FO groups and were significantly lower than the CO group. Compared with the CO group, the MO group but not FO group had significantly lower aortic protein levels of p65NF-κB, p38MAPK, and VCAM-1. The aortic protein levels of p-p65NF-κB and p-p38MAPK were significantly lower in the MO group than the FO group.ConclusionIn conclusion, MO is more potent than FO in preventing atherosclerosis, and the possible mechanism may be by downregulating p38MAPK/NF-κB signaling pathway, decreasing VCAM-1 and macrophage, and inhibiting proliferation and migration of SMC.

Metatranscriptomic methods involving RNA sequencing (RNA-seq) are powerful tools for evaluating the gene expression profiles of transcriptionally-active microbes that inhabit the tissues of animals. Bivalve molluscs, like all invertebrates, are holobionts and sites of interactions between host animals and both prokaryotic and eukaryotic symbionts. The present communication describes the metatranscriptomic profile of the resident microorganisms that inhabit the gut of blue mussels, Mytilus edulis, under standard laboratory conditions. Each of the eight mussels described herein were housed in isolated microcosms with routine husbandry for 14 days before their gut tissues were sampled and subjected to RNA-seq. Subsequent mRNA reads that aligned to the mussel genome were removed, and the non-host reads were annotated for function and pathway analyses. Under laboratory conditions, the resident gut microbiota expressed genes associated mostly with aerobic energy processes, with other notable contributions from metabolism and protein processing genes. At the pathway level, the most abundant complete pathways expressed in the resident gut microbial communities were related to aerobic cellular respiration, nucleotide biosynthesis, and catabolism. These data represent novel, baseline microbial gene expression information from the gut of mussels, which are crucial for future research examining the mussel holobiont and bivalve microbial ecology. Public retrieval and secondary analyses of these metatranscriptomic profiles are highly encouraged.

This article discusses the mass disappearance of intertidal mussels in eastern Canada after an unusual winter cold snap in February 2023. The decline in mussel abundance is concerning due to its impact on coastal biodiversity. The cold snap, which saw temperatures drop below -20°C, is believed to be the main driver of the mass disappearance. Other factors such as predation, ice scour, and wave action were ruled out as causes. The article highlights the potential implications of climate change on the future of coastal ecosystems and emphasizes the need to study the frequency of extreme weather events. [Extracted from the article]

The purpose of this application, under Articles 23.9.3 and 81.1 of the Code, is to conserve the current usage of the specific name of the northeast Pacific Ocean marine mussel Mytilus californianusConrad, 1837, the identity of which has never been questioned. After examining the type specimens of Mytilus zonariusLamarck, 1819 and Mytilus canalisLamarck, 1819, Huber (2010) concluded that they were M. californianus and used the former as its valid name. Neither Mytilus zonarius nor M. canalis have been used as the valid name of Mytilus californianus between 1819 and 2010. The name Mytilus californianus has been used as the valid name of this species in thousands of publications between 1837 and 2020. It is proposed to conserve the name Mytilus californianusConrad, 1837 by reversal of precedence with the names Mytilus zonariusLamarck, 1819 and Mytilus canalisLamarck, 1819. [ABSTRACT FROM AUTHOR]

Copyright of African Journal of Biological Sciences is the property of African Journal of Biological Sciences and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Interest in leveraging suspension feeders, such as marine bivalves, to exert top‐down control on organic matter (OM) loading in estuaries is gaining momentum. Not only can these faunal engineers alleviate the consequences of nutrient pollution, but they may also bolster the critical blue carbon services provided by coastal ecosystems—a potential dual, mitigating effect on cultural eutrophication and climate change. Ribbed mussels, Geukensia demissa, offer a useful model for assessing faunally driven carbon (C) and nitrogen (N) processes in these systems and their relationships with faunal density. Combining bulk geochemical analyses with Bayesian stable isotope mixing model frameworks (MixSIAR), we quantified the effect of mussels on the source and amount of organic C and N deposited to the benthic floor (i.e., sedimentation), accumulated in surface sediments, and stored in aboveground Spartina alterniflora in Georgia salt marshes. Relative to areas without mussels, mussel presence shifted the source of deposited and accumulated OM to a more allochthonous makeup; amplified the amount of deposited, but not accumulated, allochthonous and autochthonous OM; and enhanced aboveground storage of C and N. Both sources of OM accumulated in sediments as well as standing stocks of C and N were highly and positively correlated with local mussel density (ind. m−2) but unrelated to neighboring mussel density (ind. ∼25 m−2) in adjacent, non‐mussel areas. This work provides new evidence that suspension feeders, through their faunal engineering activities, can interact powerfully and synergistically with primary producers to enhance the blue carbon services of marshes and counteract coastal eutrophication. Plain Language Summary: Coastal ecosystems regulate carbon and nitrogen generated both inside and outside of their physical extents—important ecosystem services that can help combat the consequences of pollution and climate change. Suspension‐feeding animals living in these ecosystems, like mussels, may enhance this regulation by feeding on algae suspended in the overlying tidewater and depositing their waste to the habitat bottom. There, these deposits can accumulate in sediments or be taken up by plants. We studied how ribbed mussel presence and density influence carbon and nitrogen regulation processes in Georgia, USA salt marshes. By comparing deposits in marsh areas with and without mussel aggregations with elemental and stable isotope analyses, we found that mussels amplify the reclamation and import of marsh‐derived and marine‐derived carbon and nitrogen, respectively. We took a similar approach to sediment and found that concentrations of both sources of carbon and nitrogen increase as mussel density increases within their aggregations. Finally, we found that mussel presence and density boosted cordgrass biomass and, in turn, carbon and nitrogen storage. Mussel populations are disproportionately augmenting the role of salt marshes in regulating carbon and nitrogen pollution and should be incorporated into coastal management decisions related to these challenges. Key Points: Through suspension feeding and biodeposition, mussels augment sedimentation of organic matter (OM) produced inside and outside of salt marshesOM accumulation in sediments and aboveground storage increases with increasing mussel densityMussels bolster the capacity of salt marshes to counteract coastal eutrophication and provide blue carbon services [ABSTRACT FROM AUTHOR]