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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]

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]

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]

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]

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]

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]

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]

Molluscs are among the most valuable resources of the Philippines, an archipelagic country of 7,107 islands bounded by 36,000 km of coastline and 26.6 million ha of coastal waters. In 2020, production from mussels and oysters alone valued at PhP1.552 billion. As primary sources of food and livelihood for marginalized fisherfolk, they are considered important in food security, nutrition, and poverty alleviation. Nevertheless, for almost a century, mollusc culture remained small-scale, with most fish farmers investing in non-fed species, like mussels and oysters. Moreover, mollusc culture in the country is still dependent on wild sources of seed stocks, making production unsustainable and unreliable. This dependence on the wild seed stocks will continue until the issue of the lack of commercial-scale hatcheries or the limited capacity of existing hatcheries to produce seeds, both for top and emerging mollusc aquaculture species, is resolved. Although technologies from broodstock management to post-harvest are available in some species, the lack of capital and the limited government support limit these artisanal fishers from doing large commercial-scale culture. This paper summarizes what has been done and published on the leading mollusc species cultured in the Philippines. Future research activities may be designed based on the research gaps to refine available technologies and develop new ones to improve culture production. The lack of or limited relevant information on the viable economics of the different culture techniques at different culture phases, the limited availability of post-harvest technologies, and the sparse or lack of genetic information for these leading mollusc species are among the gaps that need to be addressed. [ABSTRACT FROM AUTHOR]

Shallow coastal environments are becoming more susceptible to marine heatwaves, particularly in Atlantic Canada, which is experiencing higher rates of ocean warming compared with the global average. Understanding bivalves' tolerance to heatwaves in Atlantic Canada is especially important, given the magnitude of bivalve aquaculture in this region. In this study, the physiological state of four commercially important bivalve species—blue mussel (Mytilus edulis Linnaeus, 1758), eastern oyster (Crassostrea virginica (Gmelin, 1791)), soft shell clam (Mya arenaria Linnaeus, 1758), and hard clam (Mercenaria mercenaria (Linnaeus, 1758))—was observed during a naturally occurring heatwave in Prince Edward Island, Canada. The metabolism, feeding physiology, and scope for growth of each species were compared. Results from this study, and comparisons with the literature, show interspecific variability in the metabolic rate and feeding physiology between species, but generally oysters, soft shell clams, and hard clams were less impacted during the heatwave compared with the blue mussels. Additionally, only the scope for growth of mussels declined throughout this experiment, which may be explained by cumulative heat stress, as temperatures experienced during this heatwave exceeded the thermal tolerance limits of mussels. [ABSTRACT FROM AUTHOR]

Marine species exhibit a multitude of biological rhythms, in accordance with their complex ecosystem governed by sun, earth and moon trajectories. Because of the inclination of the earth's axis, the high Arctic ecosystem is characterized by several months of permanent illumination during the polar day. The persistence of biological rhythms in this photic context remains unclear. Yet, this information is crucial for the understanding of polar ecosystems functioning, as well as to predict the impact of future climate changes. Particularly, the impact of extreme photoperiods on recent invasive species remains largely unknown. Here, we investigate how environmental cycles shape the behavior of a re-emerging polar resident, the mussel Mytilus sp. during polar day (17 April to 26 August 2020; Svalbard, Ny-Ålesund, 78°56ʹ N, 11°56ʹ E). Our results show that in the high Arctic polar day, mussels' behavior is shaped by both the photoperiod and the diel sun trajectories above the horizon. In addition, mussels also exhibit tidal, semi-lunar, and lunar rhythms of valve opening amplitude. We argue that these rhythms may have ecosystems functioning implications, and that the mussels' ability to deal with drastic light regimes may explain their northward expansion and new resettlement in high Arctic. [ABSTRACT FROM AUTHOR]

Sex steroid hormones occur in the bivalve tissues. Testosterone (T), various oestrogens, and progesterone have been reported in this group of organisms and the amounts of these hormones have been correlated with seasonal variation and reproduction. Yet, neither the role nor the origins of sex steroids are fully clarified. Thus, we tested the hypothesis that, apart from the esterification process, the aromatisation of androgens to oestrogens can help balance T levels during gonadal development in both sexes using Mytilus edulis trossulus as a model species. The highest testosterone concentrations were found in developed male and female gonads (IV reproductive stage of gametogenesis). The highest aromatisation efficiency was also found in the developed male and female gonads, but also in the gills. During the other stages of gametogenesis (II, III, V-I), a decrease in both testosterone concentration and aromatisation efficiency was observed in the gonads of males and females, as well as in the gills of males. However, the decrease in testosterone concentration did not affect the 17β-oestradiol concentration in mussel tissues. Thus, together with the esterification process, the ongoing aromatisation in bivalve tissues may help keeping balanced T levels. [ABSTRACT FROM AUTHOR]

Intestinal microbes are essential participants in host vital activities. The composition of the microbiota is closely related to the environmental factors. Predator presence may impact on intestinal microbiota of prey. In the present study, stone crab Charybdis japonica was used as potential predator, an external stress on mussel Mytilus coruscus, to investigate the intestinal microbiota alteration in M. coruscus. We set up two forms of predator presence including free crab and trapped crab, with a blank treatment without crab. The composition of intestinal microbiota in mussels among different treatments showed significant differences by 16S rRNA techniques. The biodiversity increased with trapped crab presence, but decreased with free crab presence. Neisseria, the most abundant genus, fell with the presence of crabs. Besides, the Arcobacter, a kind of pathogenic bacteria, increased with free crab presence. Regarding PICRUTs analysis, Environmental Information Processing, Genetic Information Processing and Metabolism showed differences in crab presence treatments compared with the blank, with a bit higher in the presence of free crab than trapped crab. In conclusion, trapped crab effects activated the metabolism and immunity of the intestinal flora, but free crabs made mussels more susceptible to disease and mortality, corresponding to the decreased biodiversity and the increased Arcobacter in their intestine. [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. [ABSTRACT FROM AUTHOR]

Synthesizing materials that stimulate the natural growth of living tissues and restore damaged parts of the body is one of the most challenging problems in regenerative medicine. Despite being the most commonly used biomaterial, synthetic hydroxyapatite is a calcium phosphate with a relatively low rate of bioresorption related to new tissue growth. For specific applications, the speed of resorption is essential, and synergy between polymer and hydroxyapatite composite materials from natural sources can be developed. Therefore, this study attempts to synthesize hydroxyapatite from poultry and mariculture by-products and produce spheres with alginate for use as biomaterials for tissue repair. Shells different shellfish and eggs were used as sources of CaCO 3 and added to a phosphoric acid solution as precursors in wet synthesis. The powders were dried, thermally treated and characterized. Structural analysis revealed hydroxyapatite in nanometric crystallites (61–72 nm) with high crystallinity (86–89%). The calcium phosphate obtained from Mozambique shellfish acquired the best characteristics. Beads with various sizes and porosities were produced through changes in the process parameters, including the type and size of the dripper, speed of agitation of the solution, and type of drying. The results show that the type of dripper strongly influences the size of the beads and that the rotation speed influences the sphericity. The styling directly influenced the fluid absorption, demonstrating that the spheres dried by lyophilization can absorb up to 223% of their weight. In comparison, samples dried in a desiccator could absorb only 112% of their weight in body fluids. The porosity of the optimized beads was up to 90%, which is similar to that of human bone, and they did not show cytotoxicity. Therefore, the beads composed of alginate and hydroxyapatite produced here have the potential for application in tissue repair. [ABSTRACT FROM AUTHOR]

Plastic pollution has emerged as a prominent environmental concern over recent decades, particularly due to its critical implications for seafood safety. In light of this, an investigation was conducted to assess the abundance and characteristics of microplastics (MPs) in Unio mancus Lamarck 1819, a freshwater bivalve inhabiting Atatürk Dam Lake in Türkiye. For the MPs analysis, a total of 20 U. mancus Lamarck 1819 specimens were collected from the lake, with shell lengths ranging from 7.7 to 10.1 cm and soft tissue weights varying from 21.46 to 49.1 g. The findings of this study revealed the presence of MPs-like particles in 12 out of the 20 mussels, with a total count of 42 particles. MPs concentration ranged from 0 to 9.9 MPs per individual, with an average of 1.89 ± 0.57 MPs per individual. When considering the soft tissue weight, MPs concentration ranged from 0 to 50.51 MPs per 100 g, with a mean of 6.91 ± 2.56 MPs per 100 g. µ-Raman analysis further confirmed that 90% of the particles were composed of various polymers. Among these, polypropylene (PP) constituted 40%, polyethylene (PE) accounted for 20%, polyethylene terephthalate (PET) comprised 10%, Nylon-6 constituted 10%, and cellulose represented 10% of the identified particles. Notably, fragments were the predominant shape observed in the samples, and the majority of MPs were less than 100 µm in length. This study provides valuable foundational data for establishing frequent MP monitoring routines in freshwater environments, considering that bivalves serve as key vectors of MP contamination in the context of human exposure. [ABSTRACT FROM AUTHOR]

The processing of fishery products is not only for food consumption, but also the use of waste from these products has increased in recent years with the sustainability policy. Mussel meat, which is one of the aquatic products with high consumption in our country, is a delicious food product with high nutritional properties. While mussels contain low amount of fat and cholesterol; It also contains high levels of protein, carbohydrates, vitamins A, B1, B2, B6, B12, C and minerals such as calcium, iron, magnesium, phosphorus and selenium. It is seen that mussels are not only consumed as food, but also mussel shells are used as waste in the production of food packaging. In this study, mussels; mussel shell, mussel cultivation, purchasing and preservation, its importance in terms of human health and obtaining edible film from mussel Shell powder are included. [ABSTRACT FROM AUTHOR]

Over the last decade, the biological impact of microplastics in marine environments has become a serious global concern. Beyond their biological complexity, it is believed that many lethal and sublethal effects related to microplastic toxicity are triggered by oxidative stress and subsequently activated pathways. Thus, for marine organisms, having efficient mechanisms to fight the accumulation of oxidizing agents becomes indispensable to counteract the effects of microplastics. To date, our knowledge of the physiological effects of microplastics and the response of the antioxidant system in benthic species remains limited. The purpose of our study was to investigate the effects of short‐term exposure on the levels of two fundamental nonprotein antioxidants, glutathione (GSH) and ovothiol (OSH), in different tissues of Mytilus galloprovincialis. Our results show that the metabolism of OSH and GSH in mussels is clearly affected by acute microplastic exposure, and that the antioxidant response differs based on sex and reproductive stage. Indeed, although in the reproductive season the overall levels of GSH and OSH in different tissues significantly increase with respect to the control condition, the antioxidant response of the organisms, especially males, in the spent stage often exhibits a biphasic U‐shaped dose–response effect. Our study represents a pivotal investigation on the effects of microplastic exposure on the pools of two fundamental cellular antioxidants, with potential ecodiagnostic implications to forecast the stress status after exposure to microplastics, and highlights the possibility that the effects of these contaminants may vary over time based on the physiological condition of the animals. Environ Toxicol Chem 2023;42:1607–1613. © 2023 SETAC [ABSTRACT FROM AUTHOR]

This study is first study reporting the microplastic abundance in soft tissues of a bivalvae Brachidontes pharaonis collected from 4 stations of İskenderun Bay. A total of 245 B. pharaonis specimens were examined and results showed that among examined specimens, 95 of them contained microplastic in their soft tissues. When all the data combined, mean MP abundance was found as 0.4±0.5 MPs ind-1 and 0.3±0.4 MPs g-1 ww. Fibers were predominant type of MPs and accounted for 75% of total extracted MPs, followed by fragments (25%). Majority of MPs were less than 1 mm and black. Fourier transform infrared spectroscopy (FTIR) showed that the extracted MPs were polypropylene (PP), polyethylene (PE), and polyethylene terephthalate (PET). Identified polymer types indicate that aquatic biota impacted by the anthropogenic influences such as agriculture, farming, fishing, household, etc. Results obtained in this study contribute the knowledge related with the microplastic contamination levels in marine biota. [ABSTRACT FROM AUTHOR]

Noisy human activities at sea are changing the acoustic environment, which has been shown to affect marine mammals and fishes. Invertebrates, such as bivalves, have so far received limited attention despite their important role in the marine ecosystem. Several studies have examined the impact of sound on anti-predator behavior using simulated predators, but studies using live predators are scarce. In the current study, we examined the separate and combined effects of boat sound playback and predator cues of shore crabs (Carcinus maenas) on the behavior of mussels (Mytilus spp.). We examined the behavior of the mussels using a valve gape monitor and scored the behavior from the crabs in one of two types of predator test conditions from video footage to control for effects from potential, sound-induced variation in crab behavior. We found that mussels closed their valve gape during boat noise and with a crab in their tank, but also that the stimulus combination did not add up to an even smaller valve gape. The sound treatment did not affect the stimulus crabs, but the behavior of the crabs did affect the valve gape of the mussels. Future research is needed to examine whether these results stand in situ and whether valve closure due to sound has fitness consequences for mussels. The effects on the well-being of individual mussels from anthropogenic noise may be relevant for population dynamics in the context of pressure from other stressors, their role as an ecosystem engineer, and in the context of aquaculture. [ABSTRACT FROM AUTHOR]

Existing bone tissue engineering strategies aim to achieve minimize surgical trauma, stabilize the injured area, and establish a dynamic osteogenic microenvironment. The cutting‐edge bone glue developed in this study satisfies these criteria. Inspired by the excellent adhesive properties of mussels, herein, a super osteogenic glue (L‐DPZ) that integrates poly(vinyl alcohol), L‐dopa amino acid, and zeolitic imidazolate framework‐8 characterized by catechol–metal coordination is used to successfully adhere to hard tissue with a maximum adhesive strength of 10 MPa, which is much higher than those of commercial and previously reported bone glues. The stable hard tissue adhesion also enables it to adhere strongly to luxated or broken teeth, Bio‐Oss (a typical bone graft material), and splice fragments from comminuted fractures of the rabbit femur. Then, it is testified that the L‐DPZ hydrogels exhibit satisfactory biocompatibility, stable degradability, and osteogenic ability in vitro. Moreover, the ability to anchor Bio‐Oss and sustained osteogenesis of L‐DPZ result in satisfactory healing in calvarial bone defect models in rabbits, as observed by increased bone thickness and the ingrowth of new bone tissue. These results are expected to demonstrate solutions to clinical dilemmas such as comminuted bone fracture fixation, bone defect reconstruction, and teeth dislocation replantation. [ABSTRACT FROM AUTHOR]

Background. The diarrhoeal shellfish poisoning (DSP) toxin is a powerful marine biological toxin. Eating DSP toxin-contaminated mussels will lead to serious gastrointestinal diseases. To this end, a method for the detection of DSP toxins using near-infrared reflectance spectroscopy combined with pattern recognition is proposed. Material and methods. In the range from 950−1700 nm, spectral data of healthy mussels and DSP-contaminated mussels were obtained. To select the optimal band subsets, a band selection algorithm based on model cluster analysis was applied. As distinguishing DSP toxin-contaminated mussels from healthy mussels is a classification problem of imbalanced data, an improved fuzzy support vector machine-based recognition method was proposed. The influence of the parameters of the band selection algorithm and the fuzzy support vector machine on the model performance was analyzed. Results. Compared with the traditional support vector machine, the proposed model has better performance in detecting DSP toxins and is not affected by the imbalance ratio. Its geometric mean value can reach 0.9886 and the detection accuracy can reach 98.83%. Conclusion. The results show that as an innovative, fast and convenient analytical method, near-infrared spectroscopy is feasible for the detection of DSP toxins in mussels. [ABSTRACT FROM AUTHOR]

The bay mussel, Mytilus trossulus, is an animal that can survive extracellular ice formation. Depending on air and ocean temperatures, freeze tolerant intertidal organisms, like M. trossulus, may freeze and thaw many times during the winter. Freezing can cause protein denaturation, leading to an induction of the heat shock response with expression of chaperone proteins like the 70 kDa heat shock protein (HSP70), and an increase in ubiquitin-conjugated proteins. There has been little work on the mechanisms of freeze tolerance in intertidal species, limiting our understanding of this survival strategy. Additionally, this limited research has focused solely on the effects of single freezing events, but the act of repeatedly crossing the freezing threshold may present novel physiological or biochemical stressors that have yet to be discovered. Mytilus are important ecosystem engineers and provide habitat for other intertidal species, thus understanding their physiology under thermal extremes is important for preserving shoreline health. We predicted that repeated freeze exposures would increase mortality, upregulate HSP70 expression, and increase ubiquitin conjugates in mussels, relative to single, prolonged freeze exposures. Mytilus trossulus from Vancouver, Canada were repeatedly frozen for a combination of 1 × 8 h, 2 × 4 h, or 4 × 2 h. We then compared mortality, HSP70 expression, and the quantity of ubiquitin-conjugated proteins across experimental groups. We found a single 8-h freeze caused significantly more mortality than repeated freeze–thaw cycles. We also found that HSP70 and ubiquitinated protein was upregulated exclusively after freeze–thaw cycles, suggesting that freeze–thaw cycles offer a period of damage repair between freezes. This indicates that freeze–thaw cycles, which happen naturally in the intertidal, are crucial for M. trossulus survival in sub-zero temperatures. [ABSTRACT FROM AUTHOR]

Reef‐forming species form integral aspects of coastal ecosystems, but are rapidly degrading world‐wide. To mitigate these declines, nature managers increasingly rely on the restoration of habitat‐structuring, reef‐forming species by, for example, introducing artificial reefs that may directly function as complex reef habitat. Since the use of biodegradable structures to restore biogenic reefs is becoming a popular technique, its effectiveness as reef habitat must be assessed. Therefore, we examine the trophic complexity on experimental large‐scale biodegradable artificial reefs using food web network analysis.We placed biodegradable artificial reefs on soft‐sediment intertidal flats in the Dutch Wadden Sea in a large‐scale (~650 m) and 2.5‐year‐long experiment. We compared food web networks and biodiversity indicators between biodegradable reefs and bare controls and quantified species composition inside and near the artificial reef community to assess the expansion of the reef community.During 2.5 years, we observed that artificial reefs changed food web networks compared to bare controls: in species richness (+76%), link density (the number of interactions per species; +15%) and the fraction of basal species (species of lowest trophic level; +40%), but lowered the connectance: the realized fraction of all possible links between species (−33%). Their effects on food web networks increased over time with a higher species richness (+22%) and more complex food web (link density +13%) on the artificial reef 2.5 years after deployment compared to 1.5 years. However, the effects of the reefs did not extend beyond the reef structures; the species composition and biodiversity of macrozoobenthos near the reefs were comparable to the control.Synthesis and applications. This study shows that biodegradable artificial reefs offer an effective tool for the restoration of food web complexity and biodiversity of intertidal soft‐sediment systems. However, application needs to be carefully considered as the reef‐building species did not expand beyond our structures, despite the ambitious spatial extent of this experiment. Therefore, we recommend restoration practitioners to design artificial reefs in such a way that they generate ecosystem connectivity (facilitation of higher trophic levels) and biogeomorphological effects on a landscape scale (reef expansion beyond the structures). [ABSTRACT FROM AUTHOR]

The commercial onshore aquaculture of the spiny lobster Panulirus ornatus, while in its infancy, has progressed rapidly from the enabling research that continues at the University of Tasmania. The development of lobster feeds, both fresh and manufactured, has been critical to the success of this emerging aquaculture sector. Fresh feeds derived from mussel represent the gold standard in terms of the growth performance of juvenile lobsters. Nonetheless, concerns regarding availability, sustainability, and potential biosecurity issues of fresh feeds highlight the importance of developing manufactured feeds for lobster aquaculture. Wild lobsters are assumed to have a balanced natural diet that allows for standard growth and development, and as such natural diets are often used as a reference for feed development. Similarly, the gut microbiota associated with a natural diet is assumed to reflect a healthy microbial assemblage. The aim of this study was to compare the microbiota of the hindgut and hepatopancreas of cultured P. ornatus fed with a commercial prawn pellet or mussel to that of wild spiny lobster juveniles. Gut samples were analysed using Oxford Nanopore 16S rRNA gene sequencing. Based on principal coordinate analysis, the gut bacteria of cultured lobsters were different from the wild juveniles. The core microbiota of the hindgut and hepatopancreas libraries were phyla Proteobacteria (Gamma, Alpha) and Bacteroidetes. Vibrio was the most dominant genus in both organs. The differences in bacterial relative abundance were mainly between cultured (pellet-, mussel-fed) and wild lobsters. In conclusion, bacteria in the cultured lobsters had significantly different profiles to that of the wild juveniles, indicating that current onshore aquaculture practices alter the gut microbiota. A number of different feeding and culture practices may be required if the aim of closed culture practices is to attain a gut microbiota in cultured animals that is representative of that found in wild spiny lobsters. [ABSTRACT FROM AUTHOR]

The mussel M. galloprovincialis is a bivalve that is extensively cultivated in coastal waters of the Temperate Northern Atlantic, South Africa, and China. In the present study, the variations of allometric indices, sex ratio, and occurrences of the black and brown shell coloration and gonadal ripening stages in this bivalve were studied over a 20-month period in a mussel population from a mollusk farm in the northwestern part of the Black Sea. The allometric indices were applied as the measures of the overall environmental status for the mussel development, with the elongation index (H/L) being the most sensitive one. The obtained allometric index values (H/L = 0.52 ± 0.02, D/L = 0.38 ± 0.01) were comparable with those observed in clean waters of the Black Sea. The noted biases in the mussel sex ratio towards males (♀:♂ = 1:2.8) on farm collectors and towards females (♀:♂ = 1.6:1) on the seafloor under the farm were attributed to changing environmental conditions. The mean ratios of the number of mussels with brown and black shell coloration varied from 1:3.2 on the collectors to 1:1.8 on the seafloor. The mass spawning was found to start earlier in mussel males than in females. The biological characteristics in question are applicable for assessing the impact on mussel settlements and for long-term monitoring of marine environment in other water bodies of the World Ocean. [ABSTRACT FROM AUTHOR]

To solve the problems of high labor intensity and poor cleaning effect of traditional cleaning methods of mussels, a mussel high-pressure water jet cleaning platform was built. Firstly, high pressure water jet cleaning experiment was carried out on a mussel shell with jet pressure, target distance, and incident Angle as variables and jet impact force and jet impact pressure as evaluation indexes. Then, the multi-factor combination experiment is designed by Design-Expert software, and the mathematical model of jet impact force and jet impact pressure were established. The optimal combination of mussel high-pressure water jet cleaning parameters was obtained by using the Box-Behnken response surface; Finally, the optimized cleaning parameters are used for jet cleaning experiments to verify the effectiveness of the parameters. The results show that when the fan nozzles with a jet angle of 65 ° and an inner diameter of 2 mm are used for high-pressure water jet cleaning, the jet impact pressure is 0. 011 MPa when the jet pressure is 9. 66 MPa, the target distance is 99. 88 mm and the incident angle is 75. 38°. The jet impact pressure is far less than the pressure bearing capacity of the overall surface of the shell. The cleaned mussel watch case is complete without cracks, and all kinds of stubborn dirt attached to the watch case are basically removed. The cleaning effect is significantly improved compared with the traditional cleaning method. The application of high-pressure water jet technology in mussel cleaning can effectively improve the cleaning degree of the mussel source and the level of industrial fine treatment. At the same time, it also has a certain reference significance for the cleaning of other bivalves. [ABSTRACT FROM AUTHOR]

Biological early warning systems (BEWSs) monitor the behaviour or physiology of living organisms as an indirect mechanism to sense local environmental changes, and have become a widely established tool for monitoring water pollution. Complementary to conventional chemical and physical techniques, their strength lies in the ability to continuously monitor water quality, providing direct and rapid warning of toxic discharges. Bivalve molluscs (mussels and clams) are ideal sensing organisms for BEWSs, owing to their: high water filtration capacity; sensitivity to numerous, diverse pollutants; considerable longevity; high abundance; and wide range of physical responses to environmental change. Two behavioural metrics of bivalves have dominated in ecotoxicological studies, and consequently spawned development into BEWSs: valve movements, typically measured using electromagnetic techniques; and bivalve cardiac activity, typically measured using infrared photoplethysmography. However, other, less studied bivalve behaviours may exhibit pollutant impacts, including shell growth and dissolution, premature egg/larval release, horizontal movement, and burial. Such metrics may, with further research, provide bases for future BEWSs, some through current valve movement monitoring technology, others potentially through acoustic telemetry. Future bivalve-based BEWSs may become more informative and sensitive through the greater nuance that lies in integration of different metrics simultaneously and/or multi-species monitoring. Future directions may seek techniques that reduce disturbance to bivalves and enable observation of a more natural mode of behaviour, through using untethered, or entirely unequipped, specimens. With rigorous controls for individual- and population-level variation, bivalves have great power as biosensors and, bolstered by the scope for future advancements, this field has the potential to make significant contributions to future water quality management. [ABSTRACT FROM AUTHOR]

Mytella strigata (Hanley, 1843) is an invasive mussel species that has rapidly spread in China in recent years. Here, we tested the utility of three mitochondrial gene fragments, COI, 12S, and 16S, and two nuclear gene fragments, D1 28S and 18S-ITS1, for characterizing the levels of genetic diversity among and within populations using 191 M. strigata specimens collected in China to aid ongoing efforts to identify the origin of the invasion as well as molecular genetic studies. M. strigata exhibited two sex-associated haplogroups according to the COI and 12S sequences. The ratio of female-lineage to male-lineage COI and 12S sequences was 149:22 and 72:7, and the genetic distances between haplogroups were 6.56 and 9.17, respectively. Only one haplotype was detected among the 18S-ITS1 sequences (413 bp), and three haplotypes were detected among the D1 28S sequences (296 bp). The haplotype diversity of both the female-lineage COI and 12S sequences was greater than 0.5, and the nucleotide diversity of the 12S, 16S, D1 28S, and 18S-ITS1 sequences was less than 0.005 in all six populations in China. Our findings indicated that COI is the most useful gene fragment for genetic diversity studies of M. strigata populations; D1 28S and 18S-ITS1 sequences would be useful for species identification because of their low intraspecific diversity. Our genetic analysis of the COI sequences revealed Colombia as the most likely origin of M. strigata in China and showed that the invasive populations in China have recently experienced or are currently experiencing a population bottleneck. [ABSTRACT FROM AUTHOR]

The extensive presence of microplastics (MPs) in marine ecosystems constitutes a major threat to aquatic environments. The gametes of the marine invertebrate Mytilus galloprovincialis , which is essential for coastal ecosystems, are released directly into the water, potentially exposing them to environmental microplastics (EMPs). This study examined the effects of exposing M. galloprovincialis gametes to 50 or 100 µg/L EMP for 1 h on fertilization rates, larval quality, and the molecular mechanisms underlying the induction of apoptosis and shell growth. Our findings show that increased EMP concentrations correlate with reduced fertilization success and higher rates of larval malformations, indicating negative impacts on embryonic development. Additionally, DNA degradation in larvae is related to the EMP concentration. The apoptosis-associated proteins Bax, P53, and Cas-3 are upregulated, whereas Bcl-2 and DNA-ligase are downregulated with increasing EMP concentrations. Prothymosin-ɑ (PTMA), which is crucial for cell proliferation, also decreases with increasing EMP concentrations, contributing to impaired cell proliferation and growth imbalances. Reduced HRG gene expression is correlated with decreased shell growth and larval malformations. This study underscores the detrimental impact of EMPs on bivalve gametes, which impacts fertilization success and larval quality and highlights the potential risks to species survival and marine ecosystem stability. [Display omitted] • Mussels' larvae were obtained from cross-fertilization of exposed gametes to EMP. • The exposure caused a reduction of fertilization rate and higher ratio of malformed larvae. • The EMP caused DNA degradation and increased the expression of apoptotic markers. • Larvae with low shell quality and high apoptotic markers expression can threaten the sustainability of the specie. [ABSTRACT FROM AUTHOR]

Growing micro- and nano-plastic (MNPs) pollution in the environment poses a threat to marine animals. Due to their excellent filtration capacity, bivalves can easily ingest MNPs, which could be translocated to open circulation system with potential risks. In the present study, the accumulation and elimination of MNPs (200 nm and 1 µm) in the mussel hemolymph serum and hemocytes were firstly quantified, and the differential sensitiveresponses of two subpopulations of hemocytes were then explored by in vivo exposure under environmentally relevant concentration of MNPs (200 µg/L). We demonstrated that MNPs were readily translocated into hemolymph serum, but were immediately followed by efficient internalization by hemocytes. Remarkably, concentrations of MNPs in hemolymph were only 0.63 and 0.39 times lower than the ambient exposure concentration. Granulocytes displayed a much higher potential of accumulating MNPs than the agranulocytes. MPs were more readily internalized by granulocytes, with their estimated maximum bioaccumulation factor (BCF) of 0.29 L/g. Due to the primary function of phagocytic encapsulation of MNPs by granulocytes, lysosome features especially the decline of subsequent lysosome membrane potential could be a potential sensitive biomarker in response to MNPs exposure. Our results provided insights on the bioaccumulation of MNPs at the cellular levels in marine bivalves. [Display omitted] • Concentrations of MNPs in hemolymph were 0.39-0.63 times lower than the ambient concentration. • Hemolymph serum had an important transport function of MNPs. • Hemocytes especially granulocytes were the highly efficient phagocytic scavengers of MNPs. • Lysosome membrane permeability of granulocytes was a potential sensitive biomarker to MNPs. [ABSTRACT FROM AUTHOR]

The toxigenic Alexandrium species can secrete paralytic shellfish toxins (PSTs) into seawater during their growth, potentially threatening marine organisms and human health. The release of intracellular toxins during the growth cycle of Alexandrium spp. and the uptake of dissolved PSTs by shellfish are still not clear. Three strains of A. minutum GY-H46, A. minutum ATDH and A. pacificum ATHK were used to explore the dynamic variations in profile of intra- and extracellular toxins during their growth cycles. And a comparative study was carried out on the accumulation and tissue distribution of PSTs in mussels Mytilus unguiculatus exposed to the dissolved and particulate toxins during a 5-days period. Results showed that the toxin cell quotas increased rapidly during the early exponential growth period, then decreased gradually and plateaued at the stationary growth period for ATHK and ATDH, while gradually increased during the stationary growth period for GY-H46. The toxin cell quotas for GY-H46, ATDH and ATHK ranged from 8.3 to 21.5, 5.3 to 11.7 and 7.4 to 9.3 fmol cell−1, respectively, during the whole growth cycle. The contents of extracellular toxins increased gradually throughout the growth of GY-H46, ATDH and ATHK, and the molar mass percentage of extracellular toxins ranged from 53% to 72%, 20% to 46% and 36% to 68%, respectively. Mussels can actively uptake the dissolved PSTs from seawater medium, and mainly accumulate toxins in the digestive glands. The accumulation level of PSTs from the dissolved phase by mussels was about 1% of that from feeding on microalgal cells. The results of this study will contribute to a comprehensive understanding of the dynamic release of intracellular PSTs during microalgal growth and the accumulation of dissolved toxins by shellfish. [Display omitted] • The toxin cell quotas for the three Alexandrium spp. were markedly different. • The three Alexandrium spp. secreted toxins during the whole growth cycle. • The extracellular toxins underwent chemical transformations. • Mussels can actively uptake the dissolved PSTs from seawater. • The accumulation level of PSTs was low in mussels exposed to the dissolved toxins. [ABSTRACT FROM AUTHOR]

Biomineralisation of bivalve shells raises questions at the level of genes to the final calcified product. For the first time, gene expression has been studied in association with growth increment deposition in the mussel Mytilus galloprovincialis. A short-term experiment highlighted that biomineralisation genes exhibit a rhythm of expression consistent with the observed tidal increment formation. Long-term mark-recapture experiments were conducted in three Mediterranean environments and revealed that the mussel shells harbour complex incrementation regimes, consisting of daily, tidal and a mixed periodicity of ∼1.7 growth increment.d−1 formed. The latter is likely related to the local tidal regime, although the mussels were continuously submerged and exposed to a small tidal range. The pattern of growth increments shifted from mixed to daily in Mediterranean lagoon, and to tidal at sea, probably linked to biological clocks. Based on our results and the literature, a hypothetical model for mussel shell increment formation in various habitats is proposed. [Display omitted] • Increment formation of Mytilus galloprovincialis is a rhythmic process. • Different shell increment regimes were observed as a function of month and location. • Environment alone cannot explain shell growth patterns observed in mussel. • Growth patterns observed are likely set by environment and biological clocks. [ABSTRACT FROM AUTHOR]

Since the identification of Vibrio mediterranei as a causative agent in mass mortalities of pen shells across the Mediterranean, elucidating its pathogenicity, virulence, and interactions with other bivalves has gained importance. While the cellular and immune responses of bivalves to various Vibrio species have been extensively studied, the infectious characteristics of this Vibrio species, particularly in the context of pen shell outbreaks, remain unclear for other bivalves. Therefore, to evaluate its pathogenicity, we investigated the histological and oxidative effects on the Mediterranean mussel (Mytilus galloprovincialis), a key species in aquaculture. Two distinct infection setups were established: one involving the inoculation of seawater with the bacterial isolate and another involving direct injection of the bacteria into the mussels. After a 24-h exposure period, histological evaluations were conducted on the mantle, gill, and digestive gland tissues of the mussels. Additionally, measurements of superoxide dismutase (SOD), catalase (CAT), glutathione- S -transferase (GST), and lipid peroxidation levels were performed in the gill and digestive gland tissues. Oxidative responses were significantly elevated in both infection setups compared to the control group, with the directly injected samples exhibiting the highest oxidative responses (p < 0.05). Histological findings indicated that tissue-specific responses to host-pathogen interactions were consistent under both infection conditions. Notable observations included intense hemocytic infiltration in tissues, epithelial hyperplasia, and vacuolization in the gills, as well as focal necrotic areas in the digestive gland. The findings of this study indicate that V. mediterranei , a relatively novel pathogen, can provoke significant acute immune responses and tissue-level reactions in M. galloprovincialis , a species that is both widely distributed and vital to the food chain. These insights into the potential susceptibility of mussels underscore the need for further comprehensive research and inform the development of effective management strategies. [Display omitted] • Vibrio mediterranei can induce acute immune responses and notable histopathological changes in Mytilus galloprovincialis. • Infected mussels showed significant increases in SOD, CAT, GST, and LP levels, particularly under direct injection conditions. • Intense hemocytic infiltration, hyperplasia, and vacuolization in gills, focal necrotic areas in digestive gland, were observed. • These findings highlight the threat of V. mediterranei to mussel farming, stressing the need for further research andbetter management. [ABSTRACT FROM AUTHOR]

The study of mussels (Mytilus galloprovincialis) has grown in importance in recent years due to their high economic value and resistance to pathogens. Because of the biological characteristics revealed by mussel genome sequencing, this species is a valuable research model. The high genomic variability and diversity, particularly in immune genes, may be responsible for their resistance to pathogens found in seawater and continuously filtered and internalized by them. These facts, combined with the lack of proven mussel susceptibility to viruses in comparison to other bivalves such as oysters, result in a lack of studies on mussel antiviral response. We used RNA-seq to examine the genomic response of mussel hemocytes after they were exposed to poly I:C, simulating immune cell contact with viral dsRNA. Apoptosis and the molecular axis IRFs/STING-IFI44/IRGC1 were identified as the two main pathways in charge of the response but we also found a modulation of lncRNAs. Finally, in order to obtain new information about the response of mussels to putative natural challenges, we used VHSV virus (Viral Hemorrhagic Septicemia Virus) to run some functional analysis and confirm poly I:C's activity as an immunomodulator in a VHSV waterborne stimulation. Both, poly I:C as well as an injury stimulus (filtered sea water injection) accelerated the viral clearance by hemocytes and altered the expression of several immune genes, including IL-17, IRF1 and viperin. [Display omitted] • Poly I:C acts as an antiviral immunostimulant in mussels, activating apoptosis pathways and IRFs/STING-IFI44/IRGC1. • The response is specific and different from that induced by a VHSV. • A network of interactions between lncRNAs and coding genes (IFI44, TRIM56, DHX40 and IRGC) has been identified. • Poly I:C enhances hemocytes' ability in removing viral particles. • Poly I:C leads changes in gene expression after a VHSV waterborne infection. [ABSTRACT FROM AUTHOR]

This study has reviewed the naturally occurring bioadhesives produced in marine and freshwater aqueous environments and in the mucinous exudates of some terrestrial animals which have remarkable properties providing adhesion under difficult environmental conditions. These bioadhesives have inspired the development of medical bioadhesives with impressive properties that provide an effective alternative to suturing surgical wounds improving closure and healing of wounds in technically demanding tissues such as the heart, lung and soft tissues like the brain and intestinal mucosa. The Gecko has developed a dry-adhesive system of exceptional performance and has inspired the development of new generation re-usable tapes applicable to many medical procedures. The silk of spider webs has been equally inspiring to structural engineers and materials scientists and has revealed innovative properties which have led to new generation technologies in photonics, phononics and micro-electronics in the development of wearable biosensors. Man made products designed to emulate the performance of these natural bioadhesive molecules are improving wound closure and healing of problematic lesions such as diabetic foot ulcers which are notoriously painful and have also found application in many other areas in biomedicine. Armed with information on the mechanistic properties of these impressive biomolecules major advances are expected in biomedicine, micro-electronics, photonics, materials science, artificial intelligence and robotics technology. [ABSTRACT FROM AUTHOR]

Bacteria of the Arcobacter- like spp. represent emerging foodborne zoonotic pathogens in humans and animals. Their increasing presence in seafood, suggesting higher occurrence in seawater due to marine pollution, is raising some environmental concern. Although Arcobacter is frequently detected in diseased oysters and stressed bivalve species, no data are available so far on its potential pathogenicity or interactions with the immune system of the bivalve host. In this work, responses to challenge with two strains of Malaciobacter marinus IRTA-19-131 and IRTA-19-132, R1 and R2), isolated from adult Crassostrea gigas during a mortality event in 2019 in Spain, were investigated in the mussel Mytilus galloprovincialis. In vivo experiments were performed in larvae (48 h post-fertilization), and in adult mussels at 24 h post-injection, in order to evaluate the pathogenicity for early developmental stages, and the hemolymph immune responses, respectively. Both R1 and R2 were moderately pathogenic to early larvae, with significant decreases in the development of normal D-veligers from 104 and 103 CFU/mL, respectively. In adults, both strains decreased hemocyte lysosomal membrane stability (LMS), and stimulated extracellular defense responses (ROS production and lysozyme activity). The interactions between mussel hemocytes and M. marinus were investigated in in vitro short-term experiments (30–90 min) using the R1 strain (106–108 CFU/mL). R1 decreased LMS and induced lysosomal enlargement, but not cell detachment or death, and stimulated extracellular ROS production and lysozyme release, confirming in vivo data. Moreover, lysosomal internalization and degradation of bacteria were observed, together with changes in levels of activated mTor and LC3, indicating phagocytic activity. Overall, the results indicate the activation of both extracellular and intracellular immune defenses against M. marinus R1. Accordingly, these responses resulted in a significant hemolymph bactericidal activity, with a large contribution of hemolymph serum. The results represent the first data on the potential pathogenicity of Arcobacter isolated from a shellfish mortality to bivalve larvae and adults, and on their interactions with the immune system of the host. [Display omitted] • Two Arcobacter (M. marinus) strains were isolated from an oyster mortality event. • Both strains were moderately pathogenic for early Mytilus larvae. • In vivo challenge of adult mussels elicited strong immune responses in hemolymph. • In vitro exposure triggered efficient intra and extracellular defenses in hemocytes. [ABSTRACT FROM AUTHOR]

The California ribbed mussel, Mytilus californianus , is an ecosystem engineer crucial for the survival of many marine species inhabiting the intertidal zone of California. Here, we describe the first reference genome for M. californianus and compare it to previously published genomes from three other Mytilus species: M. edulis , M. coruscus , and M. galloprovincialis. The M. californianus reference genome is 1.65 Gb in length, with N50 sequence length of 118 Mb, and an estimated 86.0% complete single copy genes. Compared with the other three Mytilus species, the M. californianus genome assembly is the longest, has the highest N50 value, and the highest percentage complete single copy genes. This high-quality genome assembly provides a foundation for population genetic analyses that will give insight into future conservation work along the coast of California. [ABSTRACT FROM AUTHOR]

The green-lipped mussel (Perna canaliculus) originates from New Zealand. To preserve the health benefits of green-lipped mussel meat, it is freeze-dried to make a long-lasting powder. The powder is used to treat arthritis because of its potential anti-inflammatory properties. The report describes a 54-year-old woman who developed immediate rhinoconjunctival and respiratory symptoms after inhaling green-lipped mussel powder she gave to her dog for arthritis. A skin prick test with green-lipped mussel powder was performed. Protein extracts from P canaliculus were separated by sodium dodecyl-sulfate polyacrylamide (SDS) gel electrophoresis and probed with serum from patients and serum preincubated with green-lipped mussel extract. Bound immunoglobulin E (IgE) was detected by specific anti-human-IgE antibodies, and IgE-binding proteins were subsequently identified by liquid chromatography and mass spectrometry. The skin prick test was positive for green-lipped mussel. Specific IgE against green-lipped mussel extract was detected using Western immunoblotting. These potential allergenic proteins were identified by mass spectrometry as actin, tropomyosin, and paramyosin. All three allergens are reported for the first time for P canaliculus. Actin is a major allergen in Paphia textile, paramyosin in Sarcoptes scarbiei, and tropomyosin in Haliotis discus. For all IgE-binding proteins, the software AllCatPro predicted high allergenicity, supporting our conclusion that these proteins from P canaliculus may also be allergenic. The identification of allergens from P canaliculus provides the opportunity for specific tests to assess the frequency of allergic reactions to P canaliculus. [ABSTRACT FROM AUTHOR]

Bacillus velezensis is a type of microorganism that is beneficial to humans and animals. In this work, a protease-producing B. velezensis strain Z-1 was screened from sludge in the sea area near Qingdao (deposit number CGMCC No. 25059). The response surface methodology was used to analyze protease production, and the optimal temperature was 37.09 °C and pH 7.73 with the addition of 0.42% NaCl, resulting in maximum protease production of 17.64 U/mL. The optimum reaction temperature and pH of the protease of strain Z-1 were 60 °C and 9.0, respectively. The protease had good temperature and pH stability, and good stability in solvents such as methanol, ethanol and Tween 80. Ammonium, NH4+,and Mn2+ significantly promoted enzyme activity, while Zn2+ significantly inhibited the enzyme activity. The protease produced by strain Z-1 was used for the enzymolysis of mussel meat. The mussel hydrolysate exhibited good antioxidant function, with a DPPH free radical removal rate of 75.3%, a hydroxyl free radical removal rate of 75.9%, and a superoxide anion removal rate of 84.4%. This study provides a reference for the application of B. velez protease and the diverse processing applications of mussel meat. [ABSTRACT FROM AUTHOR]

Steaming process is the most popular method for cooking mussels worldwide. The effect of this cooking process on some toxic (Cd, Ni, Pb), essential (Cr, Cu, Fe, Mn, Zn) elements, minerals (Na, K, Ca, Mg), total lipids, and fatty acid profiles in the Mediterranean mussels (Mytilus galloprovincialis) harvested from the Black Sea was studied. Different approaches to assess the benefits and risks (n‐6/n‐3, PUFA/SFA, AI, TI, h/H, EDI, THQ, HI, TR, and HQEFA) were employed. In general, steaming process significantly modified some essential elements and minerals concentrations as well as the fatty acid profiles. Compared to the raw samples, this culinary practice resulted in an increased concentration of Na, Mg, Zn, and saturated fatty acids and a decrease of polyunsaturated fatty acids. Significant changes in the lipid quality indices (PUFA/SFA, AI, TI, and h/H) from the raw samples were observed. No effect on the DHA content was found. However, the significant increase in the absolute content of EPA + DHA indicates that steaming does not compromise the nutritional quality of mussels. Target hazard quotients (THQs) and hazard index (HI) from elemental intake were below 1, indicating that the steamed M. galloprovincialis pose no hazard for the consumers. The target risk (TR) values for Pb, Cr, and Ni were calculated, evaluated, and showed acceptable or negligible levels. In addition, the benefit–risk ratio indicated that the steamed M. galloprovincialis are safe for human consumption. [ABSTRACT FROM AUTHOR]

Traditional detection of aquatic invasive species via morphological identification is often time‐consuming and can require a high level of taxonomic expertise, leading to delayed mitigation responses. Environmental DNA (eDNA) detection approaches of multiple species using Illumina‐based sequencing technology have been used to overcome these hindrances, but sample processing is often lengthy. More recently, portable nanopore sequencing technology has become available, which has the potential to make molecular detection of invasive species more widely accessible and substantially decrease sample turnaround times. However, nanopore‐sequenced reads have a much higher error rate than those produced by Illumina platforms, which has so far hindered the adoption of this technology. We provide a detailed laboratory protocol and bioinformatic tools (msi package) to increase the reliability of nanopore sequencing to detect invasive species, and we test its application using invasive bivalves while comparing it with Illumina‐based sequencing. We sampled water from sites with pre‐existing bivalve occurrence and abundance data, and contrasting bivalve communities, in Italy and Portugal. Samples were extracted, amplified, and sequenced by the two platforms. The mean agreement between sequencing methods was 69% and the difference between methods was nonsignificant. The lack of detections of some species at some sites could be explained by their known low abundances. This is the first reported use of MinION to detect aquatic invasive species from eDNA samples. [ABSTRACT FROM AUTHOR]

Plastic has become one of the most prominent contaminants in recent decades, posing a major environmental threat with critical implications for seafood safety. Thus, we investigated the abundance and characterization of the microplastics (MPs) in the sediment and bivalves from Çıldır Lake, Almus Dam Lake, and Kartalkaya Dam Lake in Turkey. The abundance of the MPs ranged from 19-156 MP kg-1 in the sediments, while 0.75-10.0 MP individual-1 (indiv.-1) in Anodonta sp., 0.16-1.00 MP indiv.-1 in Dreissena polymorpha, 0.50-2.50 indiv.-1 in the Unio damescensis was detected. ATR-FTIR was used to identify four distinct polymer types, with polyethylene terephthalate being the most prevalent. Fiber predominated in bivalve samples, whereas fragments in sediment and MPs were often <500 µm in length. Our data could serve as a foundation for a frequent monitoring routine in Turkish lakes since bivalves are one of the key vectors of MP contamination in humans. [ABSTRACT FROM AUTHOR]