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Limnoperna fortunei (L. fortunei) (Dunker, 1857), the golden mussel, is an invasive species possessing exceptional environmental adaptability and a destructive impact on water systems and artificial structures. To better conservation of freshwater ecosystems by controlling this mussel, it is essential to study its distribution, potential for invasion, environmental tolerance and biological traits.This paper outlines the distribution of L. fortunei in Asia and South America, as well as its potential for future invasion in freshwater habitats, along with the research methods employed.We find that the mussel had a temperature tolerance range of 8–35 °C and a pH range was 5–10, with some individuals surviving in extreme conditions for extended periods.We find that temperature was a decisive factor for success at reproductive stages, larval development and adult growth.The biological traits of L. fortunei are discussed, focusing on feeding habits, attachment characteristics and locomotion, with an emphasis on byssus structure, foot proteins and adhesion mechanisms. The study elucidates the impact of flow velocity, light exposure and substrate material on their attachment, with the optimal attachment being identified at a flow velocity of 0.3–0.9 m/s. Additionally, the mussel exhibits strong light avoidance performances and a preference for rough surfaces.Extensively‐researched control strategies are classified and summarized, primarily categorized into physical, chemical and biological control, with an outline of their respective strengths and limitations. [ABSTRACT FROM AUTHOR]

The research included 120 specimens of Pinna nobilis cultivated at a commercial park for oyster (Ostrea edulis) and black mussel (Mytilus galloprovincialis) cultivation. Research was carried out from 2012 to 2016, prior to the start of the mass extinction of fan mussel in the Mediterranean During the study period, the average sea temperature at a depth of 3 m was 14.87 ± 4.22 °C, ranging from 7.83 to 24.90 °C. The age of the specimens at the beginning of sexual maturity was approximately three years. The average length of the specimens throughout the study was 293.01 ± 16.58 mm. Gonad status was monitored monthly by sampling. The gender ratio in the study was 46 females (38.4%), 50 males (41.6%), and 24 undetermined individuals (20%). In our study, the results showed that males mature slightly earlier than females. The main spawning season occurred during the warmer part of the year when seawater exceeded 18 °C, starting in May and lasting until November. During the study, the GSI varied as expected and peaked in June (12.1), increasing from May to September. [ABSTRACT FROM AUTHOR]

Contaminants compounds like Heavy Metals and Polycyclic Aromatic Hydrocarbons (PAH's) are primarily sourced from industrial and urban areas. As pollutants, these chemical elements and compounds are potentially toxic and present the capacity to negatively impact the ecosystem, especially the most sensitive ones such as estuaries. Bivalves' species have been successfully utilized as monitoring tools to evaluate pollutants bioaccessibility around the globe. The present study assessed heavy metals (Zn, Cd, Ni, Fe, Cr, Cu and Pb), As and PAH's levels in two mollusk species (Perna perna and Crassostrea rhizophorae) from Santos Estuarine System, in São Paulo State, in order to compare the effectiveness of each species in the biomonitoring process. According to the obtained data, Perna perna mussels may be better indicators of environmental pollution than Crassostrea rhizophorae oysters for some metals (Iron and Nickel) and hydrocarbons. On the other hand, in the present study, oysters had a higher capacity for retaining zinc, copper, and cadmium, due to their peculiar physiological characteristics. [ABSTRACT FROM AUTHOR]

Objective: Using bivalves to indicate aquatic pollutants was favorable for discerning the negative effects of high levels of metal accumulation in tissue. We investigated the correlation between trace metal accumulation and the tissue oxidative response of two bivalves. Methods: The Asian green mussel Perna viridis and the blood cockle Tegillarca granosa were sampled along with seawater and sediments from three locations around Pattani Bay, Thailand. Accumulation of nine trace metals (cadmium, cobalt, copper, chromium, nickel, manganese, iron, zinc, and lead) in seawater, sediments, and tissue and the oxidative tissue response were evaluated. Metal bioaccumulation factor, biota–sediment accumulation factor, and histopathology were also indicated. Result: The present study found that P. viridis and T. granosa were macroconcentrators and bioaccumulative of cadmium, and their tissue accumulation of cadmium was strongly related to lipid peroxidation activation. Perna viridis exhibited a higher oxidative response than T. granosa, as indicated by malondialdehyde, catalase, and reduced glutathione levels. Conclusion: The present study indicated that P. viridis and T. granosa were macroconcentrators and bioaccumulative of cadmium, and their tissue accumulation of cadmium was strongly related to lipid peroxidation activation. Research has shown discernible negative effects of a high level of metal accumulation in tissue, and deformed and damaged tissues were present in the gills, digestive glands, intestines, and feet of P. viridis and T. granosa. Impact statementBivalves' structural and physiological alterations are associated with trace metal accumulation in their tissue. Tissue accumulation of cadmium has an outstanding impact on a bivalve's tissue stress and response, which influences the organisms' health, though bivalves have a high ability to accumulate and concentrate pollutants in their tissues. [ABSTRACT FROM AUTHOR]

The present study aimed to evaluate and compare feeding responses of the non-native and native bivalves, the dark false mussel Mytilopsis leucophaeata and the scorched mussel Brachidontes darwinianus, respectively, by offering different concentrations of seston from the coastal lagoon where these species coexist after dark false mussel introduction (Rodrigo de Freitas Lagoon, Rio de Janeiro-Brazil). For this purpose, independent laboratory experiments were carried out under five concentrations of seston to test the differences in clearance and ingestion rates of bivalves as a function of increasing concentrations of suspended particulate matter (SPM) on seston. In addition, from the integrated analysis of data obtained in experiments, it can be inferred about the efficiency levels of these species to remove SPM from seston and their effects on water turbidity and nutrient concentrations (total carbon, nitrogen, and phosphorus). Our hypothesis was that the non-native bivalve is more efficient to clear and ingest SPM from seston compared to the native one, which may lead to competitive advantages to the successful invasion of M. leucophaeata in coastal lagoons. Native species did not show a significant difference in clearance and ingestion rates with increasing concentrations of seston. Whereas the non-native bivalve showed a slight tendency to increase its clearance and ingestion rates with the increase in seston concentrations, evidencing its plasticity to adjust its feeding responses. The native bivalve was significantly more efficient to clear and ingest SPM at the lower seston concentration (i.e., close to natural concentrations found in the lagoon) compared to the non-native bivalve, which, on the other hand, showed a significant increase in its ingestion rates at the higher concentration tested (140 mg SPM L-1). Thus, the present results did not suggest food competition between the non-native M. leucophaeata and the native B. darwinianus in the introduced system. However, M. leucophaeata increased its feeding response with experimental increment in seston concentration, which suggests species ability to benefit from conditions of increased inputs of organic matter and higher primary production that could mediate its establishment in introduced systems. [ABSTRACT FROM AUTHOR]

Information on freshwater mussel behavior in the sediment is scarce worldwide, especially in the Amazon. Laboratory experiments were used to measure the responses of the single mussel species Castalia ambigua in relation to combinations of two co‐occurring different morphotypes (Morphotype I with an elongated shell and Morphotype II with a rounded shell), and three different densities (four, eight, and 16 mussels). Horizontal movements (cm) were calculated by summing changes in the position of each specimen and the shell exposure at the sediment–water interface was obtained by measuring (mm) the exposed part of the shell. Castalia ambigua presented different patterns of shell exposure and horizontal movements linked with shell shape and density. Castalia ambigua Morphotype I remained less exposed with 4 mussels. In contrast, this morphotype was more exposed and tended to aggregate in treatments with 8 and 16 mussels, similar to observations of Morphotype II at all densities. Morphotype II is mainly found in low hydrodynamic energy habitats, suggesting that patches with high densities may stabilize the substrate around the shells of Morphotype I, which is associated with high hydrodynamic energy habitats. We suggest that these patterns may be associated with intrinsic factors of the species, such as reproduction, sexual dimorphism and feeding. Moreover, additional studies using other mussel species belonging to the families Hyriidae and Mycetopodidae are important, since the behavior of these mussels in the sediment may provide useful information on their functional roles in river ecosystems. [ABSTRACT FROM AUTHOR]

Vibrio parahaemolyticus is a foodborne pathogen diffusely distributed in the marine environment and often isolated from raw seafood belonging to different species, mostly shellfish. Ingestion of under- or uncooked seafood contaminated by V. parahaemolyticus can cause severe gastrointestinal symptoms in humans. Due to its ability to withstand low temperatures, Vibrio spp. could survive in frozen seafoods for long periods by entering the viable but nonculturable state (VBNC) and may constitute an unrecognized source of food contamination and infection. In the present study, seventy-seven frozen bivalve molluscs (35 mussels; 42 clams) were subjected to the detection and enumeration of viable V. parahaemolyticus using standard culture methods. VBNC forms were detected and quantified by applying an optimized protocol based on Propidium Monoazide (PMA) and Quantitative PCR (qPCR). All samples were negative for both the detection and enumeration of V. parahaemolyticus by the standard culture methods. VBNC forms were detected in 11.7% of the samples (9/77), with values ranging from 1.67 to 2.29 Log CFU/g. Only clam samples were positive for the detection of VBNC forms. The results of this study highlighted that VBNC V. parahaemolyticus may be present in frozen bivalve molluscs. Further data on the prevalence of VBNC V. parahaemolyticus in frozen seafood are needed in order to perform a robust risk assessment. [ABSTRACT FROM AUTHOR]

Perkinsus marinus belongs to the Chromista Kingdom and is recognized as an opportunistic parasite of mollusks native to the west coast of the Atlantic Ocean. The native range of this species is the Atlantic Ocean, however, it was introduced to the Gulf of California (GC) by a transfaunation of oysters. This microorganism has invaded new niches in the GC and continues to colonize different species of bivalve mollusks. For the first time, P. marinus was detected in the mussel Mytella strigata from the southeast coast of the GC in 2020 by staining and molecular techniques. The moderate number of cells of this myzozoan in the mussel coincides with the reports for other species of ostreids, venerids, and mytilids in the area, which suggests that it is expanding its geographical range and host species. The invasive potential of the parasite in new environmental niches and species of mollusks with commercial importance elevate the need for a risk assessment. [ABSTRACT FROM AUTHOR]

High-nutrition components and antioxidant compounds have been discovered in many marine organisms in recent years, especially oysters and mussels; but, the two bivalves have not been studied extensively in Vietnam. Therefore, both oysters and green mussels from Long Son, Vietnam were collected for investigation. Results showed that the total macronutrient contents in green mussels were greater than those of oysters, with glutamic acid being the most abundant amino acid in both oysters and green mussels at 1.35 and 1.25 g/100 g, respectively. Total relevant mineral content was 521,954 mg/100 g in oyster flesh, while that in green mussels was 496,847 mg/100 g. Specifically, the zinc content was 30.30 mg/100 g in oysters, 21.96 times more than that in green mussels (1.38 mg/100 g). Biological mixtures of peptides were obtained through enzymatic hydrolysis, and their calculated catalytic efficiencies in oysters and green mussels were 0.051 and 0.067 mg/mL/s, respectively. The antioxidant activity of these peptides was determined by IC50 values in DPPH, with 6.39 mg/mL for oysters, and 10.4 mg/mL for green mussels, and IC50 values in ABTS with 18.0 mg/mL for oysters, and 18.3 mg/mL for green mussels. The sequences of the four most abundant peptide fractions in oyster and green mussel hydrolysates were identified by LC-MS; the two fractions identified in oysters were Asn-Lys-Gln-Ala (F1) and Val-Val-Val-Asp-Val-Gly-Ile (F2), and those in green mussels were Gly-Arg-Thr-Tyr (F3), and Pro-Thr-Gln-Val-Lys-Leu (F4). Tyrosine, a powerful nucleophile, was found in F3. As a result, it is reasonable to believe that green mussels have stronger ABTS free radical scavenging activity than oysters. These results will provide a real insight for research on antioxidant processes involving biological peptides from oysters and green mussels in Vietnam. [ABSTRACT FROM AUTHOR]

Three species of mussels collected from fresh‐ and low salinity (10 psu or lower) brackish‐water environments in southern Thailand, Singapore, northern Borneo and south Sulawesi formed a new, well‐supported and distinct mytilid clade based on molecular phylogeny. All are small (< 30 mm) species with either radially ribbed or smooth shells. Internally, the upper edges of the ascending lamellae of the outer and inner demibranchs are, respectively, fused to the mantle lobes and visceral mass. A new genus Parabrachidontes is proposed to accommodate the three species. Of the species in the new genus, one is described as new (Parabrachidontes amnicus sp. n.), and the other two poorly known species (P. leucostictus and P. cochinensis) are re‐described. The Parabrachidontes clade is closely related to Mytella, Perna and Arcuatula. Together, they formed a well‐supported clade, most members of which have ctenidial edges attached to the mantle and/or visceral mass. These genera are clearly distinct phylogenetically from two other mytilid clades containing brackish‐ and fresh‐water species with ctenidia free of the mantle: one comprising the genera Limnoperna and Sinomytilus (together constituting the Limnoperninae), and the other Xenostrobus and Vignadula (forming the Xenostrobinae). We therefore suggest the existence of at least three lineages of mytilids living in rivers and estuaries of East Asia and Australasia. [ABSTRACT FROM AUTHOR]

Recently, there is a greater interest for the development of mussel Mytilus edulis hatcheries, particularly for the production and commercialization of triploid bivalves. The aims of this study were to examine the efficiency of inducing triploid mussels by various treatments and to determine the effect of triploidy on larval development. To produce triploids, extrusion of the second polar body of fertilized eggs was inhibited by 6-(dimethylamino)purine (6-DMAP), cold-shock, or heat-shock treatments. Triploidy was detected by flow cytometry for all the treatments. Treatment with 6-DMAP was the most efficient with a rate of triploidy of 90%, followed by heat-shock (56%) and cold-shock (30%) treatments. No survival differences were observed between diploids and 6-DMAP-induced triploid larvae from the D-shape stage up to their settlement. Moreover, increased growth was observed in triploid larvae compared to diploid larvae. Overall, this study showed that 6-DMAP is a highly efficient method to induce triploidy in mussels, with triploid larvae having faster growth compared to diploid. [ABSTRACT FROM AUTHOR]

This contribution presents the first established population of the Chinese pond mussel Sinanodonta woodiana (Lea, 1834) (Bivalvia: Unionidae) in Greece. Previous single reports from rivers Axios and Evros need further investigation. Chinese pond mussels were collected in Lake Pamvotida (= Pamvotis or Ioannina) during a mussel field expedition in October 2020. This alien species was first detected in 2006 in a fishpond adjacent to the lake from where it possibly dispersed. The species is now widespread and abundant throughout the lake and is most possibly displacing a genetically unique population of Anodonta cygnea endemic to the lake. Species identification was confirmed with genetic cytochrome oxidase c subunit I (COI) gene barcoding sequences. A single COI haplotype was retrieved which is shared by the vast of majority of the specimens sequenced from the invaded range in Europe. Monitoring of S. woodiana presence and abundance should be widely conducted and special attention and collaboration with fish farms is urgently required to prevent its dispersal to other freshwater ecosystems. [ABSTRACT FROM AUTHOR]

The nursery culture of bivalves typically relies on the feeding of costly live microalgae, while the use of natural sources of phytoplankton for feed is uncertain due to their variable quality and abundance. Replacement diets have been applied in bivalve nursery culture to replace live microalgae with varying success. This study investigated the potential use of two concentrated microalgal diets at a range of levels of substitution with live microalgae. Shellfish Diet 1800® (called SD) and LPB™ Frozen Shellfish Diet® (called LPB) were fed to juvenile green-lipped mussels (Perna canaliculus) at five levels of substitution for live microalgae (i.e., 0, 25, 50, 75, and 100%) for 27 days. The mortality of mussels fed with 100% LPB replacement was significantly higher than the mortality of mussels fed at the lower levels of replacement, i.e., 0 and 25%. The overall final size of spat tended to decrease with the increasing level replacement of live microalgae. Proximate analysis (i.e., crude ash-free dry weight, crude protein, crude lipid, and carbohydrate) showed that only the proportion of carbohydrate content of spat was influenced by feeding treatments, with the mean total carbohydrate content of mussels tending to decrease with increasing levels of replacement of live microalgae. The results indicate that both concentrated microalgal feeds (SD and LPB) are effective at replacing live microalgae by up to 50% without compromising the survival and nutritional profile (AFDW, protein, lipid, and carbohydrate content) of juvenile green-lipped mussels and are therefore a useful resource for improving the efficiency of production. [ABSTRACT FROM AUTHOR]

The freshwater pearl mussel Margaritifera margaritifera is an endangered bivalve which is usually regarded as sedentary, although individual movement has been observed both vertically and horizontally. Little is known about the causes and rates of mussel movement. The objective of this study was to test the effect of microhabitat characteristics on the horizontal movement distance and rates of freshwater pearl mussels. A total of 120 mussels (length range 40–59 mm) were marked individually with passive integrated transponder tags, placed in stream microhabitats differing in their sediment composition and monitored biweekly over a period of 10 weeks. Mussels situated in sand-dominated habitats had a significantly higher mean movement rate (3.2 ± 4.2 cm/day, mean ± SD) than mussels situated in gravel-dominated (1.9 ± 2.7 cm/day) or stone-dominated habitats (1.8 ± 3.2 cm/day). The direction of the movements appeared random; however, an emigration from sandy habitats was observed, probably to avoid dislodgment from these hydraulically unstable habitats. This study demonstrates that freshwater pearl mussels can actively emigrate from unsuitable microhabitats. Once suitable streams with respect to physical, chemical, and biological quality were identified, it is therefore only necessary to identify suitable mesohabitats (area of 10–30 m2) when reintroducing or relocating mussels. [ABSTRACT FROM AUTHOR]

To complete their life cycle, freshwater mussels of the order Unionida depend on fishes as hosts for their obligatory parasitic larval phase, the glochidium. Here we report the first documentation of gobioid fishes as hosts of glochidia of unionid mussels in the wild in Italy and in southern Europe (outside of the Danube drainage area). We also examined the pattern of the attached glochidia. A recent review reported 326 fish species as suitable hosts for unionids, but only eight (2.5%) of these were Gobioidei. Host identification and the documentation of their benefits or threats for the interaction of the mussels with their hosts is important for conservation of freshwater mussels. But the co-existence of mussels with non-native fish species is only poorly understood, including the compatibility of these two groups. Knipowitschia panizzae and Pomatoschistuscanestrinii, two translocated sand gobies, were sampled in 2022 at the east shore of Lake Trasimeno (Italy). Two species of anodontine mussels were present at this locality, the native Anodonta anatina and the translocated Sinanodonta woodiana. Genetic data revealed that both sand gobies hosted glochidia only of A. anatina but not of S. woodiana, possibly because of seasonal bias. About 50% of the specimens of both fish species were infested. The paired fins were the most prominent targets. The examined individuals of both sand gobies carried only few glochidia (max. 5). Nevertheless, the two species showed a divergent pattern of glochidia attachment. [ABSTRACT FROM AUTHOR]

Multispectral satellite remote sensing imagery, together with appropriate modeling, have been proven to provide chlorophyll-a maps that are useful to evaluate the suitability of coastal areas for carrying out shellfish aquaculture. However, current approaches used for chlorophyll-a estimation in very shallow coastal areas often fail in their accuracy. To overcome this limitation, an algorithm that provides an accurate estimation of chlorophyll-a concentration in the coastal areas of the Ebro delta (North Western Mediterranean) using atmospherically corrected Sentinel 2 (S2) remote sensing reflectances (Rrs) has been calibrated and validated. The derived chlorophyll-a maps created have been used in a dynamic carrying capacity model that covers areas from very rich waters inside the embayment to the more oligotrophic waters in the open sea. The use of carrying capacity models is recommended to evaluate the potential of marine coastal areas for bivalve mollusk aquaculture. In this context, the depletion of chlorophyll-a is an indicator of negative environmental impact and thus a continuous monitoring of chlorophyll-a is key. The proposed methodology allows estimation of chlorophyll-a concentration from Sentinel-2 with an accuracy higher than 70% in most cases. The carrying capacity and the suitability of the external areas of the Ebro delta have been determined. The results show that these areas can hold a significant mussel production. The methodology presented in this study aims to provide a tool to the shellfish aquaculture industry. [ABSTRACT FROM AUTHOR]

Background: The order and orientation of genes encoded by animal mitogenomes are typically conserved, although there is increasing evidence of multiple rearrangements among mollusks. The mitogenome from a Brazilian brown mussel (hereafter named B1) classified as Perna perna Linnaeus, 1758 and assembled from Illumina short-length reads revealed an unusual gene order very different from other congeneric species. Previous mitogenomic analyses based on the Brazilian specimen and other Mytilidae suggested the polyphyly of the genus Perna. Methods: To confirm the proposed gene rearrangements, we sequenced a second Brazilian P. perna specimen using the "primer-walking" method and performed the assembly using as reference Perna canaliculus. This time-consuming sequencing method is highly effective when assessing gene order because it relies on sequentially-determined, overlapping fragments. We also sequenced the mitogenomes of eastern and southwestern South African P. perna lineages to analyze the existence of putative intraspecific gene order changes as the two lineages show overlapping distributions but do not exhibit a sister relationship. Results: The three P. perna mitogenomes sequenced in this study exhibit the same gene order as the reference. CREx, a software that heuristically determines rearrangement scenarios, identified numerous gene order changes between B1 and our P. perna mitogenomes, rejecting the previously proposed gene order for the species. Our results validate the monophyly of the genus Perna and indicate a misidentification of B1. [ABSTRACT FROM AUTHOR]

Perna canaliculus is endemic to New Zealand and is the top shellfish export product. However, the growth of this industry is being adversely affected by summer mortality events. To assess these health threats, differential haemocyte counts (DHC) were performed on haemolymph smears stained with Giemsa, and in vitro phagocytosis activity assays were applied in P. canaliculus for several months covering three seasons (winter, spring and summer). A new optimized classification scheme was developed for P. canaliculus haemocytes where 55% eosinophilic and 27.2% basophilic granulocytes were identified. Eosinophilic granulocytes were classified as dense, semi and small semi, and these new categories were reported herein for the first time in this species. A new haemocyte type (mixed granulocytes), which contains both acidophilic and basophilic granules, is proposed for P. canaliculus. The phagocytosis percentages were significantly affected by incubation time, indicating an increase in zymosan particle uptake from 18.42 ± 1.7% after 30 min, 32.08 ± 3.1% after 60 min and 44.74 ± 3.5% (maximum) after 120 min of incubation. The lowest phagocytosis was observed in the winter season and the highest phagocytosis in summer. This study findings provide a better understanding of the immune function of P. canaliculus haemocytes and serve as a reference for further investigations on the impacts of seasonal variations on haemocyte activity and phagocytosis. [ABSTRACT FROM AUTHOR]

High suspended loading is one of the environmental stressors which could affect survival rates and feeding activities of marine bivalves especially the coastal species. Therefore, this study aimed to examine the effects of suspended particles (SP) on filtration rates of the green-lipped mussel Perna viridis, which is a commercial bivalve species in Thai coastal waters. The large and small mussels were subjected to 250 mg and 500 mg of SP/l, and a control treatment (0 mg of SP/l) in the experimental laboratory. Filtration rates of the mussels were measured at day 0, day 15, and day 20 after the exposure to SP. The results showed that filtration rates of two class-sizes of the mussels significantly decreased after the exposure to SP for 15 and 20 days. Before the exposure to SP (day 0), the large mussels had significantly greater filtration rates than the smaller individuals, indicating the size-dependent effects. Filtration rates of the mussels decreased with increasing concentrations of SP. Gill abnormalities, e.g., loss of cilia on the gill lamella, were detected in the selected mussels at 500 mg of SP/l. The small mussels exhibited less capability in maintaining filtration rates compared with the larger mussels under high SP concentration. Moreover, changes in filtration rates over the exposure time were also discussed based in our study. Overall, the results can reflect deleterious effects of high SP on the mussels, particularly in filter-feeding activities. These findings could raise environmental concerns over high SP that could damage cultured mussels and coastal ecosystems. [ABSTRACT FROM AUTHOR]

The mechanistic approach and the potential predictive power of Dynamic Energy Budget (DEB) models are making this modelling framework increasingly popular in aquaculture management. The potential to mechanistically simulate life-history traits of a species in a changing environment has already been applied to many commercial species, including the New Zealand Greenshell™ mussel Perna canaliculus. However, the previous P. canaliculus model parameterisation, available in the Add-my-Pet (AmP) collection, has been carried out on a limited data set. We used data obtained through targeted laboratory experiments and combined it with literature data, to derive a new version of the model which included information on additional processes – such as feeding, respiration, and reproduction – and life stages: larvae and adults. We compared the performance of the previous version of the model, termed AmP-2018 with the revised model (AmP-2024), to predict the whole life-cycle of the mussel and life-history traits of interest in the context of aquaculture. The entry completeness score (0−10), which provides an indication of data quality and variety as well as model comprehensiveness and applicability, increased dramatically from 2.5 to 5.5, suggesting P. canaliculus is now the most comprehensively DEB-parameterised bivalve, while the model increased in accuracy of the predictions. The endeavour highlights several conclusions: (i) reliable temperature response data are required to establish the thermal response curve; the presence/absence of this type of data should be taken into account when assessing the completeness of a model and its applicability to predict thermal responses of a species; (ii) species-specific parameter values are preferred over general (higher taxonomic level) specific values, e.g. for tissue organics and water content, as they increase the accuracy of predictions; (iii) data pertaining to laboratory trials and to wild populations both need to be taken into account when calibrating a mechanistic model at a species level; and (iv) calculating energy requirements of any organism, including bivalves, requires data on characteristics and products often overlooked in an experimental setting. We discuss the new version of the model in the context of the knowledge and predictive power potentially gained by adding more information and data during model calibration. The obtained results and conclusions are especially relevant in aquaculture, whether for commercial rearing of mussels, or their potential application in multitrophic aquaculture systems. [Display omitted] • A DEB model for Perna canaliculus was reparameterised with targeted experimental and literature data. • The model can realistically predict the growth, development (including larval stage), and reproduction of the mussel. • Quality thermal response data is crucial for assessing thermal response curves in DEB models. • Both ex-situ and in-situ data should be considered for species-level calibration in DEB models. • We discuss calculations for closing an energy and/or mass budget in an experimental setting. [ABSTRACT FROM AUTHOR]

Harmful algal blooms (HABs) of Alexandrium pacificum have affected the Marlborough Sounds in New Zealand since 2010, posing a threat to green-lipped mussel (GLM, Perna canaliculus) farming. Previous studies have shown A. pacificum has negative effects GLM embryos and larvae. To further investigate these toxic mechanisms, in vitro bioassays were conducted on GLM spermatozoa, hemocytes, and the diatom, Chaetoceros muelleri. The three cell types were exposed to several treatments of A. pacificum for 2 h and responses were measured using flow cytometry and pulse amplitude-modulated fluorometry. Significant spermatozoa mortality was recorded in treatments containing A. pacificum cells or fragments, while hemocyte and C. muelleri mortality was recorded in cell-free treatments of A. pacificum which contained paralytic shellfish toxins (PSTs). Variation in sensitivity between cell types as well as the sublethal effects observed, emphasise the diverse toxic mechanisms of A. pacificum on co-occurring species in the environment. [Display omitted] • In vitro bioassays were used to investigate the toxicity of Alexandrium pacificum. • Treatments containing Alexandrium pacificum fragments induced sperm mortality. • Treatments containing toxic compounds induced hemocyte mortality. • Toxins reduced metabolic activity and quantum yield in Chaetoceros muelleri. • Alexandrium pacificum imparted toxicity on cells via multiple mechanisms. [ABSTRACT FROM AUTHOR]

Bivalve molluscs represent the most recognized bioindicators of freshwater pollution. However, their ability to indicate specific xenobiotics in complex exposures is unclear. In this study, we aimed to track the particular effects of the pesticide Roundup (Rnd) and the antipsychotic drug chlorpromazine (Cpz) on the mussel Unio tumidus at the simpler environmentally relevant models. We treated the mussels by Rnd (17 μg L−1), Cpz (18 μg L−1), the mixture of Rnd and Cpz at 18 °C (RndCpz), and Rnd at 25 °C (RndT) and examined their digestive glands after 14 days of exposure. We analyzed total antioxidant capacity, glutathione (GSH&GSSG) and protein carbonyls levels, total and Zn-related concentrations of metallothioneins (MT and Zn-MT, respectively), the activities of CYP450-related EROD, glutathione S-transferase, cholinesterase, caspase-3, citrate synthase (CS), lysosomal membrane integrity (NRR), and Zn level in the tissue. Shared responses were indicated as the increase of the antioxidant, Zn-MT, and EROD levels, whereas the changes of Zn concentration, NRR, and caspase-3 activity were most diverse compared to control. According to discriminant analysis, complex exposures abolished the individual response traits and intensified the harmful effects that caused a decrease in the Zn level in the RndCpz- and RndT-groups and the loss of lysosomal integrity in the RndT-group. We concluded that multi-marker expertise with the application of integrated indices had benefits when evaluating the effects of complex exposures. [ABSTRACT FROM AUTHOR]

Mytilin is one of the most important CS-αβ peptides involved in innate immune response in Mytilidae. In this study, we successfully identified four mytilin-like antimicrobial peptides (pernalins) from Asian green mussel Perna viridis by aligning the P. viridis transcriptome with 186 mytilins and myticins related sequences collected from the transcriptome data of six Mytilus species. Analysis on gene structure showed that pernalin genes had high conservation with mytilin B of Mediterranean mussel Mytilus galloprovincialis. Interestingly, all pernalin genes have a similar tissue expression feature, evidenced by the highest transcription level observed in the hemocytes and followed by the mantle. The lowest transcription level was observed in the foot and gills. qRT-PCR analysis showed that all pernalin genes were significantly down-regulated at each time points from 3 h to 48 h after Vibrio parahaemolyticus infection, suggesting their timely immune responses after bacterial infection. [Display omitted] • Four novel mytilin-like antimicrobial peptides have identified and characterized from Asian green mussel Perna viridis. • Mytilin-like in P. viridis possess conserved cysteine patterns. • Mytilin-like are ubiquitously expressed in P. viridis • Mytilin-like in hemocytes is down-regulated by Vibrio parahaemolyticus challenge. [ABSTRACT FROM AUTHOR]

Freshwater pearl mussels (family Margaritiferidae) are sensitive to human impact and environmental changes. Large declines in their abundance have prompted studies of distribution and estimations of population densities.Iturup Island, a part of Kuril Islands, Russia, is considered to be within the distribution area of freshwater pearl mussels, but this information is based on only two specimens collected several decades ago. Detailed survey of the island is challenging as most of its territory is nearly impassable.A preliminary analysis of island rivers was carried out prior to the surveys to discover potential freshwater pearl mussel habitats. Based on previous experience from European Russia, freshwater pearl mussel habitat was expected to occur in rivers flowing out of lowland lakes.Live individuals of Margaritifera laevis were found during surveys in one river together with the unionid Beringiana beringiana, which were also found in two other rivers where the predicted habitat occurred. Based on prediction and surveys, the occurrence of freshwater pearl mussels in other rivers of Iturup Island is unlikely.Pearl mussels were concentrated in a small section of the Zmeika River with a population of about 100,000 mussels. Present threats to the population include overharvest of host fish masou salmon (Oncorhynchus masou).Surveys using similar methods can help to reveal unknown freshwater mussel populations on other Kuril Islands and on the mainland. [ABSTRACT FROM AUTHOR]

Microplastics with particle size less than 5 mm are becoming a raising global environmental crisis. These pollutants were found from the poles to the equator, in continental shelves, coasts and in the oceans, moreover, they have also been identified in the water columns, sediments and even in a variety of organisms. The majority of microplastics that ended up in the oceans originate from the land. Due to their small size, they are easily accumulated in the food chain, causing harmful effects on organisms and human health. The bivalves especially caught the interest of scientific researchers because of their direct contact with microplastics through the filter-feeding habit. Therefore, it is essential to develop methods to determine the presence of microplastics in these organisms and identify their source. This study evaluated the efficiency of extracting microplastics from the tissues of green mussels (Perna viridis) using KOH 10% solution to digest and KI 50% as the separating solution. Mussel soft tissue samples were spiked five different types of microplastics: polystyrene (PS), polyvinyl chloride (PVC), polyethylene terephthalate (PET), polypropylene (PP), high-density polyethylene (HDPE) and treated with KOH 10% solution and KI 50% solution. The presence of microplastics in some green mussel species was also investigated in some mussel farming areas in Giao Thuy, Nam Dinh province, Thi Nai, Quy Nhon, Binh Dinh province and Hue city, Thua Thien Hue province. The research results showed high efficiency of microplastic extraction and recovery with the range from 76% to 97%. Microplastic concentration obtained in all mussel samples variates from 1.0 ± 0.1 particles/g to 1.7 ± 0.6 particles/g, in which fiber microplastics predominated. Microplastics in mussel samples have small sizes of < 1,000 μm and 1,000-2,000 μm, make up 74.15-82.32% and 9.76-14.71%, respectively. Purple was dominant among all mussel samples. This study proved that using KOH 10% solution and KI 50% solution to isolate microplastics is a suitable approach and can be used in monitoring studies of microplastic pollution in bivalves. [ABSTRACT FROM AUTHOR]

Understanding the limiting factors of the reproduction process in host–affiliate relationships is a high priority. We examined the effects of habitat location on the reproductive process of freshwater pearl mussels Margaritifera laevis (Bivalvia, Unionida) as a parasite using sympatric and allopatric Oncorhynchus masou masou (Actinopterygii, Salmoniformes) as a host fish. Initial infection rates of parasitic larvae (glochidia) and transformation rates to cysts (encysted glochidia) were examined for all parasite‐host combinations from three habitat locations (a total of nine combinations) to test the hypothesis that sympatric pairs of mussels and fish result in the highest success rates of glochidia infection and encystment. Measurements of glochidia‐infected fish reared in flow‐through experimental indoor tanks were taken at the initial infection point as well as at encystment, 2 weeks after the infection. Results disagreed with our hypothesis. Instead, an unexpected heterogeneity in a pathological deformity in gills explained a greater amount of variance in these processes. This deformity was responsible for reducing the initial infection rate and increasing the metamorphosis rates of initially attached glochidia to cysts. The field‐measured prevalence of the gill deformity was low in all habitat locations, indicating that the deformity occurred during the acclimation period before infection for relatively small‐sized host fish more susceptible to infection. Our results did not show the local adaptation of parasitic freshwater mussels to host fish but shed light on one of the least studied factors, providing an empirical underpinning of the importance of pathologically diversified host conditions in the reproductive processes of unionid mussels. [ABSTRACT FROM AUTHOR]

The ubiquity of microplastics in aquatic ecosystems has raised concerns over their interaction with biota. However, microplastics research on freshwater species, especially mollusks, is still scarce. We, therefore, investigated the factors affecting microplastics ingestion in the freshwater mussel Dreissena polymorpha. Using polystyrene spheres (5, 10, 45, 90 µm), we determined the body burden of microplastics in the mussels in relation to 1) exposure and depuration time, 2) body size, 3) food abundance, and 4) microplastic concentrations. D. polymorpha rapidly ingested microplastics and excreted most particles within 12 h. A few microplastics were retained for up to 1 wk. Smaller individuals had a higher relative body burden of microplastics than larger individuals. The uptake of microplastics was concentration‐dependent, whereas an additional food supply (algae) reduced it. We also compared the ingestion of microplastics by D. polymorpha with 2 other freshwater species (Anodonta anatina, Sinanodonta woodiana), highlighting that absolute and relative uptake depends on the species and the size of the mussels. In addition, we determined toxicity of polystyrene fragments (≤63 µm, 6.4–100 000 p mL–1) and diatomite (natural particle, 100 000 p mL–1) in D. polymorpha after 1, 3, 7, and 42 d of exposure, investigating clearance rate, energy reserves, and oxidative stress. Despite ingesting large quantities, exposure to polystyrene fragments only affected the clearance rate of D. polymorpha. Further, results of the microplastic and diatomite exposure did not differ significantly. Therefore, D. polymorpha is unaffected by or can compensate for polystyrene fragment toxicity even at concentrations above current environmental levels. Environ Toxicol Chem 2021;40:2247–2260. © 2021 The Authors. Environmental Toxicology and Chemistry published by Wiley Periodicals LLC on behalf of SETAC. [ABSTRACT FROM AUTHOR]

In Brazil, Anodontites trapesialis is a mussel species that occurs spontaneously in fish breeding sites. This species feeds on the remains of cultural treatments of other aquaculture species. The objective of the work is to understand the bromatological composition of mussel A. trapesialis. Individuals were selected to compose three samples of 500 g each of A. trapesialis for chemical composition, with viscera and viscera + shells being evaluated. The species presented 40.42 to 62.76 g of viscera per individual with a moisture content of 5.16% for viscera + shells and 86.5% for viscera. The mussel contains 42.6 and 12.96% crude protein, 3.16 and 1.76 of ether extract, 0.76 and 2.5% of crude fiber for viscera and viscera + shells. The total digestible nutrients were 74.16 and 36.96% for viscera and viscera + shells and 18.43 and 52.83% of mineral material for viscera and viscera + shells. A. trapesialis has relevant characteristics in its chemical composition as high protein content that gives the species potential for the human, animal, and other byproducts production. [ABSTRACT FROM AUTHOR]

Highly populated coastal environments receive large quantities of treated and untreated wastewater from human and industrial sources. Bivalve molluscs accumulate and retain contaminants, and their analysis provides evidence of past contamination. Rivers and precipitation are major routes of bacteriological pollution from surface or sub-surface runoff flowing into coastal areas. However, relationships between runoff, precipitation, and bacterial contamination are site-specific and dependent on the physiographical characteristics of each catchment. In this work, we evaluated the influence of precipitation and river discharge on molluscs' Escherichia coli concentrations at three sites in Central Italy, aiming at quantifying how hydrometeorological conditions affect bacteriological contamination of selected bivalve production areas. Rank-order correlation analysis indicated a stronger association between E. coli concentrations and the modelled Pescara River discharge maxima (r= 0.69) than between E. coli concentration and rainfall maxima (r= 0.35). Discharge peaks from the Pescara River caused an increase in E. coli concentration in bivalves in 87% of cases, provided that the runoff peak occurred 1-6 days prior to the sampling date. Precipitation in coastal area was linked to almost 60% of cases of E. coli high concentrations and may enhance bacterial transportation offshore, when associated with a larger-scale weather system, which causes overflow occurrence. [ABSTRACT FROM AUTHOR]

The green-lipped mussel Perna viridis was utilised for pollution biomonitoring in Victoria Harbour and its adjacent aquaculture area in Hong Kong. P. viridis was collected from a reference site and redeployed at five study sites for five weeks during the dry and wet seasons of 2019. Our study found various polycyclic aromatic hydrocarbons (PAHs) and heavy metals in the mussel tissue, while polychlorinated biphenyls (PCBs) and organochlorine pesticides (OCPs) were not detected. P. viridis at the reference site generally displayed lower levels of pollutants. Comparing with previous research in the 1980s and 2000s, we observed substantial reduction in the tissue levels of PAHs, PCBs, OCPs and heavy metals in P. viridis. The human health risks associated with consuming these mussels were determined to be insignificant. Our findings imply that the Harbour Area Treatment Scheme has been effective in improving the water quality in Victoria Harbour and its adjacent aquaculture area. • Mussel biomonitoring to indicate bioavailability of pollutants • Water quality improvement in Victoria Harbour and its eastern aquaculture area • Minimal human health risks of consuming mussels from the study sites • Effectiveness of the chemically enhanced primary treatment [ABSTRACT FROM AUTHOR]

Pharmaceuticals are recognised as environmental contaminants of emerging concern (CECs) due to their increasing presence in the aquatic environment, along with high bioactivity linked to their therapeutic use. Therefore, information on environmental levels is urgently required. This study examined the presence of a range of common pharmaceuticals in oysters and mussels intended for human consumption from England and Wales using stable isotope dilution tandem mass spectrometry. A range of compounds were detected in bivalve tissue, with the Selective Serotonin Reuptake Inhibitor antidepressant sertraline being most abundant, reaching a maximum concentration of 22.1 ng/g wet weight shellfish tissue. Levels of all pharmaceuticals showed seasonal and geographical patterns. A dietary risk assessment revealed that the levels of pharmaceuticals identified in bivalve molluscs represent a clear hazard, but not a risk for the consumer. This study highlights the requirement for further monitoring of the presence of pharmaceuticals and other CECs in bivalve molluscs. • Common prescription pharmaceuticals are present in bivalve molluscs within the UK. • Antidepressants are the commonest class of compounds of those monitored, with sertraline the predominant compound. • Levels of sertraline detected here are the highest concentrations reported in marine bivalve molluscs worldwide. • Seasonal and spatial variability in concentrations of detected compounds • Dietary risk assessment suggests no present concern to the human consumer. [ABSTRACT FROM AUTHOR]

Causes of worldwide freshwater mussel declines are poorly understood, and the potential role of the invasive Asian Clam, Corbicula fluminea, has received little attention.We measured survival and growth of captively‐reared juveniles of four native mussel species during 84‐day in situ exposures at 17 sites in the Rockcastle River system, Kentucky, U.S.A., where mussel declines are attributed to coal mining. We measured water temperature, a comprehensive array of water chemistry variables, and Corbicula abundance at each site during mussel exposures.Mussel survival was high (mean = 85.4%), did not differ among species, and was not related to any measured factor. In contrast, growth varied among sites by an order of magnitude, but growth responses were nearly identical for all four species. We found little evidence of water pollution from coal mining or other sources, and pollution did not explain variation in mussel growth. Growth was best explained by a model including only temperature (positive effect) and Corbicula abundance (negative effect) without interaction.Our model predicts 46% lower mass gain over 84 days for every 10‐fold increase in Corbicula abundance regardless of temperature, but growth may be reduced to unsustainably low levels in cooler streams. Previous ideas about water pollution as a cause of low growth and mussel declines were not supported by our data. Instead, the predicted strong effects of Corbicula, combined with similar responses of four mussel species, suggest that Corbicula may be an important, but overlooked, factor in widespread mussel declines. [ABSTRACT FROM AUTHOR]

Conrad's false mussel Mytilopsis leucophaeata (Conrad, 1831) and the Asian date mussel Arcuatula senhousia (Benson, 1842) are highly invasive bivalves actively spreading in the Ponto-Caspian region, which includes the basins of the Black, Azov, and Caspian seas. This study provides new records of both species from this region and gives a synopsis of known information on their ecology, substrate preferences, tolerance and adaptive potential to environmental factors such as salinity. Mytilopsis leucophaeata and A. senhousia are at different stages of colonization in the Ponto-Caspian region. While M. leucophaeata has become established in the region, approaching circumferential distribution in each sea basin, A. senhousia is in the initial phase of its dispersal. Although both species are distributed in estuarine and coastal areas, because of different salinity tolerances they are confined to zones of differing degrees of hydrological fluctuation: M. leucophaeata occurs in more estuarine conditions with fluctuating river discharges. Arcuatula senhousia avoids low salinity and is mainly absent near large rivers. In spite of this, A. senhousia generally prefers substrates of riverine origin (so called mixed sediments with prevalence of the soft fraction) and therefore its distribution reflects a compromise pattern with settlement occurring at the outer periphery of estuaries, whereas M. leucophaeata occupies areas with substantial freshwater influence. Unlike A. senhousia, M. leucophaeata usually occurs on hard substrates, however, our findings indicate that it is able to occupy other substrates in the absence of typical biotopes. Compared to A. senhousia, M. leucophaeata colonizes more diverse localities with a broader range of fluctuating conditions such as salinity and of substrate types. Both M. leucophaeata and A. senhousia in the Black Sea tend to settle on substrates that are not fully occupied by native byssus-attached bivalves. [ABSTRACT FROM AUTHOR]

An outbreak of the widely invasive mytilid mussel Perna perna is reported off Israel, long after its previously documented ephemeral occurrence in the mid-1960s. No contemporary populations are known east of the Gulf of Tunis, in the central Mediterranean Sea. Four molecular markers, the mitochondrial cytochrome c oxidase subunit I (COI), ribosomal 18S, 28S subunits (18S rRNA, 28S rRNA) and histone H3 have been used to validate samples identities. COI haplotype diversity suggests that the Israeli population is highly polymorphic, originating from multiple propagules. The present extensive beds in Haifa Bay, home to Haifa port, may point to vessel-transported introduction. The dense beds of P. perna may change intertidal habitats and their communities, and cause fouling of coastal infrastructure (e.g. marine outfalls, seawalls, jetties), as well as offshore infrastructure (e.g. offshore terminals, energy production platforms), and may incur heavy maintenance costs. [ABSTRACT FROM AUTHOR]

The invasive zebra mussel, Dreissena polymorpha (ZM), established in Europe for a long time, has recently been joined and commonly outcompeted by a new invader, the quagga mussel, Dreissena rostriformis bugensis (QM). To identify factors contributing to this displacement, we studied behavioural differences between the species: aggregation, movement, and responses to conspecifics, congeners and their alarm cues. Compared to ZM, QM were more aggregated and less motile, crawling shorter distances for a shorter time at a slower speed. Conversely, QM exhibited more nonlocomotor movements. Both species aggregated and burrowed less and showed more nonlocomotor movements in response to conspecific and heterospecific alarm cues. They also moved shorter distances in the presence of conspecific alarm cues. ZM delayed their locomotion and nonlocomotor movements, whereas QM started locomotion earlier in the presence of both alarm cues. Mussel responses to living heterospecifics resembled those to alarm cues. In mixed-species aggregations, ZM attached to conspecifics more often than to QM shells, whereas QM were nonselective. To summarize, QM are less mobile, less selective regarding attachment site and more aggregated than ZM. This allows QM to perform better in mixed-species assemblages by spending less energy on relocation and overgrowing ZM to a higher extent than vice versa. Both species responded to heterospecific signals, which is helpful in mixed-species assemblages, particularly in novel areas occupied by these invasive species. Nevertheless, similar responses to alarm cues and living heterospecifics suggest a negative interaction between the congeners. • We studied behaviour and interactions of two co-occurring invasive sessile bivalves. • Quagga mussels were more aggregated, less mobile and less substratum selective. • These traits account for their better performance in aggregations with zebra mussel. • Mussels responded to cues of living and crushed conspecifics and heterospecifics. • Responses to living heterospecifics resembled those to alarm cues. [ABSTRACT FROM AUTHOR]

Featured Application: The present study can foster nanoecotoxicology research on tropical environments and can be also applied on the maritime industry. The encapsulation of the biocide DCOIT in mesoporous silica nanocapsules (SiNC) has been applied to reduce the leaching rate and the associated environmental impacts of coatings containing this biocide. This research aimed to evaluate the effects of DCOIT in both free and nanostructured forms (DCOIT vs. SiNC-DCOIT, respectively) and the unloaded SiNC on different life stages of the bivalve Perna perna: (a) gametes (fertilization success), (b) embryos (larval development), and (c) juveniles mussels (byssus threads production and air survival after 72 h of aqueous exposure). The effects on fertilization success showed high toxicity of DCOIT (40 min-EC50 = 0.063 μg L−1), followed by SiNC-DCOIT (8.6 μg L−1) and SiNC (161 μg L−1). The estimated 48 h-EC50 of SiNC, DCOIT and SiNC-DCOIT on larval development were 39.8, 12.4 and 6.8 μg L−1, respectively. The estimated 72 h-EC50 for byssus thread production were 96.1 and 305.5 µg L−1, for free DCOIT and SiNC-DCOIT, respectively. Air survival was significantly reduced only for mussels exposed to free DCOIT. Compared to its free form, SiNC-DCOIT presented a balanced alternative between efficacy and toxicity, inhibiting efficiently the development of the target stage (larvae that is prone to settle) and satisfactorily preventing the juvenile attachment. [ABSTRACT FROM AUTHOR]

Our study documents and analyzes the absence of genetic diversity and structure of the Mapleleaf (Quadrula quadrula (Rafinesque, 1820)) (Bivalvia: Unionidae) mussel in the Lake Winnipeg, Assiniboine River, and Red River drainages (Manitoba, Canada). Previous studies have revealed patterns of genetic diversity and structure in the Mississippi and Ohio river drainages, as well as in the Laurentian Great Lakes drainage. Genotypes from six variable microsatellite loci showed that the Q. quadrula population in Manitoba was significantly differentiated from the population in the Great Lakes drainage (Ontario, Canada), supporting the existence of two Designatable Units in Canada. Conversely, there was no evidence of genetic structure within the sampled range of Q. quadrula in Manitoba. The lack of genetic structure in Q. quadrula across its distribution in Manitoba reflected its post-glacial history and use of a vagile host and necessitates that efforts should be made to ensure connectivity and maintain gene flow across the region. Given that the evidence suggests that Manitoba Q. quadrula belong to a single genetic population, movement of hatchery-propagated juvenile Q. quadrula, adult Q. quadrula, or glochidia-carrying host catfish sourced from any location in Manitoba could be used to augment declining populations or at-risk locations in Manitoba. [ABSTRACT FROM AUTHOR]

I review pre-modern (prior to approximately 800 C.E.) approaches to bivalve gathering, use, mariculture, consumption, and celebration, as practiced by several societies on the western coastlines of the Americas. I also include a brief analysis of bivalves in global cultures and histories, as well as a discussion of contemporary applications of bivalve ecosystem services globally. Herein, I provide critical insights into ancient socioecological interactions that affected the health and well-being of local human and bivalve communities. These insights include the connections between bivalve trade and sociocultural developments, the role of the bivalve in shaping human identities, and the effects of bivalve ecosystem services on the well-being of those early human groups. The lessons were garnered from the use of an array of species of bivalves, including Tivela stultorum, the Pismo clam; Leukoma staminea, the littleneck clam; Saxidomus gigantea, the butter clam; Spondylus crassisquama, a spiny oyster; and Mytilus californianus, the California mussel. These lessons may be incorporated into modern-day ecology and sustainability studies, as well as contemporary coastal planning and solution-building. Important suggestions for modern-day sustainable coastal management systems include greater utilization of bivalve services in environmental planning and further inclusion of historical ecology, traditional ecological knowledge (TEK), and other elements of the historical record in such planning frameworks. [ABSTRACT FROM AUTHOR]

Freshwater bivalves are highly threatened and globally declining due to multiple anthropogenic impacts, making them important conservation targets. Because conservation policies and actions generally occur at the species level, accurate species identification and delimitation is critical. A recent phylogenetic study of Italian mussel populations revalidated an Anodonta species bringing the number of known European Anodontini from three to four species. The current study contributes to the clarification of the taxonomy and systematics of European Anodontini, using a combination of molecular, morphological and anatomical data, and constructs phylogenies based on complete mitogenomes. A redescription of A. exulcerata and a comparative analysis of morphological and anatomical characters with respect to the other two species of Anodonta present in the area are provided. No reliable diagnostic character has emerged from comparative analysis of the morphometric characters of 109 specimens from 16 sites across the Italian peninsula. In fact, the discriminant analysis resulted in a greater probability of correct assignment to the site of origin than to the species. This confirms the difficulties of an uncritical application of visual characters for the delimitation of species, especially for Anodontinae. [ABSTRACT FROM AUTHOR]

Several biological levels are considered as signals of environmental perturbations so that integrative biological responses have been proposed in environmental monitoring activities. We evaluated the use of markers in Mytilus galloprovincialis at two different levels (protein nitration and S-nitrosylation, and geometric morphometrics) to investigate the sea coastal environmental status. We studied adductor muscle, digestive gland and valves of mussels collected from 3 sampling sites (2 disturbed + 1 control) in eastern Tyrrhenian Sea, and 2 (1 + 1) in western Ionian Sea. Molecular and morphometric markers showed significant variations in relation to environmental conditions, but the most interesting result was evidenced by the analysis of covariation between both protein post-translational modifications and geometric morphometric descriptors. The main interesting finding regards the relationship between protein nitration values (an irreversible molecular marker) of both adductor muscle and digestive gland, and geometric morphometric descriptors (that are Procrustes' distances) of valve shapes. Molecular and morphometric markers revealed useful warning systems in detecting environmental changes, even if causes and mechanisms altering both cellular metabolism and shape morphology are still unclear. Our findings suggested that pollutants affected the normal cellular metabolic pathways altering the correct functionality at higher biological levels and producing developmental detrimental noise visible on the shell. [ABSTRACT FROM AUTHOR]

The freshwater mussel (Unionida) fauna of the Yangtze River is among the most diverse on Earth. In recent decades, human activities have caused habitat degradation in the river, and previous studies estimated that up to 80% of the mussel species in the Yangtze River are Threatened or Near Threatened with extinction. However, a comprehensive and systematic evaluation of the conservation status of this fauna has yet to be completed.This study evaluated the conservation status of the 69 recognized freshwater mussel species in the middle and lower reaches of the Yangtze River, using the criteria published by the International Union for Conservation of Nature (IUCN). A new method for prioritizing species for conservation was then developed and applied termed Quantitative Assessment of Species for Conservation Prioritization (QASCP), which prioritizes species according to quantifiable data on their distribution and population status, life history, and recovery importance and potential.IUCN assessments showed that 35 (51%) species in the study region are Threatened or Near Threatened (11 Endangered, 20 Vulnerable, 4 Near Threatened). In addition, 16 species (23%) could not be assessed owing to data deficiency. Key threats to the freshwater mussel biodiversity of the Yangtze River include pollution, habitat loss and fragmentation, loss of access to host fish, and overharvesting of mussels and their host fish. The genera Aculamprotula, Gibbosula, Lamprotula, Pseudodon, Ptychorhynchus, and Solenaia were identified as particularly threatened.Data availability allowed QASCP assessment of 44 species. Only Solenaia carinata, regionally Endangered under IUCN criteria, achieved the highest QASCP rank, i.e. First Priority. The five species assessed as Second Priority were considered either regionally Endangered (one), Vulnerable (three), or Data Deficient (one) under IUCN criteria. The 23 Third Priority species were assessed as regionally Endangered (two), Vulnerable (15), Near Threatened (two), or Least Concern (four). [ABSTRACT FROM AUTHOR]

The evolutionary history and diversity of unionoid mussels in East Asia need to be clarified and would shed light on the formation process of the unique fauna of Japan. Unionoid mussels (Mollusca: Bivalvia) are unique models for understanding the process by which organisms have diversified before and after the formation of the Japanese archipelago. Unionoid mussels have poor dispersal ability, so it is thought that they would have been strongly influenced by the archipelago's formation. Therefore, the speciation and diversification processes of mussels before and after the archipelago's formation were investigated by analyzing the nuclear and mitochondrial DNA of a wide range of species, particularly those inhabiting East Asia. The evolutionary history and divergence time of these mussels were examined. Unionoid mussels were found to have higher endemicity than other freshwater organisms. Although most of the endemic unionoid mussels of Japan are likely to have diverged before the formation of the Japanese archipelago, some other Japanese unionoid mussel species, including species endemic to Lake Biwa, an ancient lake in Japan, potentially diverged after the Japanese archipelago began to separate from the continent. This suggest that adaptation to the unique habitat of the ancient lake has caused diversification in the mussels endemic to it. [ABSTRACT FROM AUTHOR]

Experiments were conducted to determine the optimum conditions for growth and survival of the green mussel, Perna viridis larvae. Effects of various temperatures and salinities, stocking densities, water exchange frequency, and natural food preference of the larvae from D-hinged to pediveliger stage were investigated. The green mussel broodstocks were collected from the natural source, and spawning occurred in captivity. All experiments were conducted in triplicate. The results demonstrated that larvae from D-hinged to pediveliger stage had better growth and survival when the temperature was between 29°C and 30°C, and salinity ranging from 30-33ppt. Stocking density from 10- 20 larvae/ml did not affect growth and survival of the larvae. Likewise, frequency of water replacement from daily to every 5 day interval did not influence the growth and survival until the pediveliger stage. During this stage, the larvae preferred a combination of Isochrysis galbana and Chaetoceros calcitrans as food in terms of better growth, and either Isochrysis galbana, Chaetoceros calcitrans, or their combination in terms of higher survival rate. [ABSTRACT FROM AUTHOR]

The mid-20th century industrial peak caused severe global lead (Pb) marine contamination. Although Europe initiated Pb emission reduction regulations in the 1980s, the short- and long-term impacts remain unclear. This study investigates the evolution of Pb contamination on the French coast through elemental and isotope analysis in oysters and mussels from the French "Mussel Watch" Program. Observations at 114 monitoring stations over four decades have shown decreasing Pb levels in these bivalve mollusks. In 1988, 95 % exceeded the background reference values; this level had dropped to 39 % by 2021. The Pb isotope ratios in bivalves from eight target sites revealed a reduction in bioaccumulated anthropogenic Pb, albeit without complete elimination. The long residence time of legacy Pb combined with inputs from diffuse urban sources likely explains the persistent presence of anthropogenic Pb on the French coast. This study endorses the importance of continuous biomonitoring to evaluate environmental regulations and policies. [Display omitted] • In 1988, Pb in bivalves exceeded background reference values at 95 % of stations. • In 2021, only 39 % of stations exceeded background reference values. • Isotope analysis revealed reduced bioaccumulated anthropogenic Pb over four decades. • Pb data demonstrated the effectiveness of implemented Pb regulatory measures. • Persisting legacy Pb and diffuse urban Pb sources require continuous biomonitoring. [ABSTRACT FROM AUTHOR]

The presence of cocaine and its metabolites and by-products has been identified in different aquatic matrices, making crack cocaine the target of recent studies. The aim of this study was to evaluate the sublethal effects of crack on the brown mussel Perna perna. Mussels were exposed to three concentrations of crack cocaine (0.5, 5.0, and 50.0 μg L−1) for 168 h. Gills, digestive glands, and hemolymph were extracted and analyzed after three different exposure times using a suite of biomarkers (EROD, DBF, GST, GPX, LPO, DNA damage, ChE, and lysosomal membrane stability [LMS]). After 48 and 96 h of exposure, EROD, DBF, GST, GPX activities and DNA strand breaks in the gills increased significantly after 48 and 96 h of exposure. Alterations in LMS were also observed in the mussels exposed to all crack concentrations after 96 and 168 h. Our results demonstrated that crack cocaine is metabolized by CYP-like and GST activities in the gills. GPX was not able to prevent primary genetic damage, and cytotoxic effects in the hemocytes were also observed in a dose- and time-dependent response. Our study shows that the introduction of illicit drugs into coastal ecosystems must be considered a threat to marine organisms. [ABSTRACT FROM AUTHOR]

Understanding the multiple agents of decline is important for the conservation of globally threatened Unionida (Class Bivalvia), but threats from non‐native species have received limited attention. To address this gap, a global meta‐analysis was conducted aimed at identifying known interactions and mechanisms of impact and informing potential effect pathways for the New Zealand unionid fauna.The main non‐native groups identified as interacting with unionids were fish (38% of published studies), macrophytes (33%), and vertebrate predators (30%), with ~70% of interactions leading to adverse impacts on mussels. Most studies used field surveys (~50%) and were conducted in rivers (~50%).Impacts occurred across the unionid life cycle (adult, glochidia, host, and juvenile), and primarily affected processes that determine the transitions between life‐cycle stages (fertilization, infestation, settlement, and maturation). The impacts of non‐native macrophytes and fish were predicted to be greater for transitional stages than the impact of vertebrate predators, which mostly affected adult mussels.New Zealand Unionida are most likely to be affected by interactions with non‐native species in lowland lakes and waterways, where connectivity for diadromous native fish hosts and high bioinvasion potential intersect. [ABSTRACT FROM AUTHOR]

For understanding the structural characteristics and the proteome of Perna shell, the microstructure, polymorph, and protein composition of the adult Perna viridis shell were investigated. The P. viridis shell have two distinct mineral layers, myostracum and nacre, with the same calcium carbonate polymorph of aragonite, determined by scanning electron microscope, Fourier transform infrared spectroscopy, and x-ray crystalline diffraction. Using Illumina sequencing, the mantle transcriptome of P. viridis was investigated and a total of 69,859 unigenes was generated. Using a combined proteomic/transcriptomic approach, a total of 378 shell proteins from P. viridis shell were identified, in which, 132 shell proteins identified with more than two matched unique peptides. Of the 132 shell proteins, 69 are exclusive to the nacre, 12 to the myostracum, and 51 are shared by both. The Myosin-tail domain containing proteins, Filament-like proteins, and Chitin-binding domain containing proteins represent the most abundant molecules. In addition, the shell matrix proteins (SMPs) containing biomineralization-related domains, such as Kunitz, A2M, WAP, EF-hand, PDZ, VWA, Collagen domain, and low complexity regions with abundant certain amino acids, were also identified from P. viridis shell. Collagenase and chitinase degradation can significantly change the morphology of the shell, indicating the important roles of collagen and chitin in the shell formation and the muscle-shell attachment. Our results present for the first time the proteome of P. viridis shell and increase the knowledge of SMPs in this genus. [ABSTRACT FROM AUTHOR]

Individual linear growth in 26 specimens of Anodonta beringiana is studied by measuring the successive annual rings on the surface of the shells. It is shown that the growth of mollusks is well described by the von Bertalanffy growth equation. The coefficients of this equation do not significantly differ between individuals, averaging k = 0.062 ± 0.011 year–1 and L∞ = 155.8 ± 19.5 mm. Species lifespan, calculated as a product of the growth constant k and the maximum longevity of mussels in the population, is 1.7. This value is close to the average species lifespan of other bivalve species. [ABSTRACT FROM AUTHOR]

• Cu accumulation variable between freshwater and marine mussels. • Both bivalve species comparable for Cu induced genotoxic responses. • γ-H2AX expression increased as a function of Cu concentration. • Correlations evident between different genotoxic biomarkers. • Freshwater mussel a suitable reference species for inland water bodies. Determination of relative sensitivity of biota following exposures to contaminants including metals is important for environmental protection. Copper (Cu), although biologically essential can be highly toxic to biota if present at higher concentrations in the natural environment. Given its ubiquitous presence within coastal and inland water bodies, we compared Cu-induced genotoxicity in two ecologically important mussel species, the freshwater Dreissena polymorpha (DP) and marine Mytilus galloprovincialis (MG), along with its tissue specific accumulation. Novel biomarker in terms of induction of gamma H2AX (γ-H2AX) foci, along with comet assay and induction of micronuclei (MN) were used to determine DNA damage response (DDR) in these two species following exposure to a range of Cu concentrations (18, 32, 56 μg L−1) for 10 days. Concentration-dependent increases in Cu concentration in gill tissue, as determined by Inductively Coupled Plasma Mass Spectrometry (ICP-MS), were paralleled by a greater degree of genotoxicity. An induction of γ-H2AX foci was present in all Cu exposure concentrations, proving this technique to be a sensitive and suitable biomarker of genotoxicity in bivalves. The multi-biomarker approach adopted here suggests firstly that in parallel with MG, which is widely used to assess the health of marine and coastal environment, DP is also suitable representative of inland water bodies, and that there is a similar mechanism of action for the induction of genotoxicity between the two species, following exposure to Cu. Secondly, for genotoxicity assessment a battery of responses could simultaneously be assessed in these two bivalve species. Finally, for adequate protection of the environment it is vital to adopt a multi-biomarker, multi-species approach to determine adverse biological effects to gain a holistic understanding of the real threat posed by contaminants to hydrosphere. [ABSTRACT FROM AUTHOR]

The Byssus, which is derived from the foot gland of mussels, has been proved to bind heavy metals effectively, but few studies have focused on the molecular mechanisms behind the accumulation of heavy metals by the byssus. In this study, we integrated high-throughput transcriptome and proteome sequencing to construct a comprehensive protein database for the byssus of Chinese green mussel (Perna viridis), aiming at providing novel insights into the molecular mechanisms by which the byssus binds to heavy metals. Illumina transcriptome sequencing generated a total of 55,670,668 reads. After filtration, we obtained 53,047,718 clean reads and subjected them to de novo assembly using Trinity software. Finally, we annotated 73,264 unigenes and predicted a total of 34,298 protein coding sequences. Moreover, byssal samples were analyzed by proteome sequencing, with the translated protein database from the foot transcriptome as the reference for further prediction of byssal proteins. We eventually determined 187 protein sequences in the byssus, of which 181 proteins are reported for the first time. Interestingly, we observed that many of these byssal proteins are rich in histidine or cysteine residues, which may contribute to the byssal accumulation of heavy metals. Finally, we picked one representative protein, Pvfp-5-1, for recombinant protein synthesis and experimental verification of its efficient binding to cadmium (Cd2+) ions. [ABSTRACT FROM AUTHOR]