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Tropomyosin has been identified as the major cross-reactive shellfish allergen, but recent studies showed the presence of other clinically relevant allergens. This study aims at determining the allergic immune responses of mice sensitized with raw and boiled shrimp extracts in comparison to recombinant tropomyosin (rTM). Female Balb/c mice were intragastrically sensitized and challenged with raw, boiled shrimp or rTM. Systemic, cellular and humoral allergic responses were compared, while allergenicity of the extracts was also compared by skin prick test (SPT) and immunoblot on shrimp allergic subjects. We showed that rTM and shrimp extracts induced IgE- and Th2-mediated allergic responses in mice, distinguished by remarkable intestinal inflammation in small intestine across all regimens. Notably, boiled shrimp extract exhibited the highest sensitization rate (73.7% of mice developed positive TM-specific IgE response) when compared with raw extract (47.8%) and rTM (34.8%). Mice sensitized with boiled extract manifested the highest allergen-specific IgE and Th2 cytokine responses than the others. Immunoblot results indicated that tropomyosin remained the major allergen in extract-based sensitization and had stronger allergenicity in a heat-treated form comparing to untreated TM, which was in line with the SPT results that boiled extract induced larger wheal size in patients. Hemocyanin and glycogen phosphorylase were also identified as minor allergens associated with manifestation of shrimp allergy. This study shows that boiled extract enhanced sensitization and Th2 responses in agreement with the higher allergenicity of heat-treated TM. This study thus presents three shrimp allergy murine models suitable for mechanistic and intervention studies, and in vivo evidence implies higher effectiveness of boiled extract for the clinical diagnosis of shellfish allergy.

Mollusc and crustacean consumption in the first 1000 d may improve maternal and child health by providing essential nutrients. However, in some contexts, molluscs and crustaceans have been associated with allergies and environmental contamination, potentially leading to adverse health and development outcomes. It is unclear whether the health benefits of consuming molluscs and crustaceans, collectively classified as shellfish in nutrition, are outweighed by the potential risks to pregnant women and children. We conducted a scoping review (PROSPERO: CRD42022320454) in PubMed, Scopus and EBSCO Global Health of articles published between January 2000 and March 2022 that assessed shellfish consumption during pregnancy, lactation or childhood (0-2 years) in relation to maternal health, child health or child development. A total of forty-six articles were included in this review. Overall, shellfish consumption was associated with higher biomarkers of environmental contaminants, with mercury being the most studied and having the strongest evidence base. The limited research on nutritional biomarker status shows an association between shellfish consumption and iodine status. Preterm birth was not associated with shellfish consumption, but newborn anthropometry showed mixed results, with several studies reporting lower birth weight with higher shellfish consumption. The few studies that examined child development and maternal health outcomes reported no significant associations. This review revealed trade-off health risks and benefits with inclusion of molluscs and crustaceans in the dietary patterns of mothers and young children. More research is needed to understand how these aquatic animal-source foods may be safely consumed and leveraged for improving human nutrition.

Per- and polyfluoroalkyl substances (PFAS) are known to bioaccumulate in aquatic organisms, such as shellfish, and have been linked to adverse human health outcomes. Increasing attention has been focused on method development for the detection of PFAS in various media; however, these methods are typically tedious, require high solvent volumes, and are time consuming. The present method used a Quick, Easy, Cheap, Effective, Rugged, and Safe (QuEChERS) extraction approach and analysis by ultra-performance liquid chromatography coupled with tandem mass spectrometry (UPLC-MS/MS) to detect 28 PFAS in Eastern oyster (Crassostrea virginica) tissue. This method was validated using limit of detection, limit of quantitation, and precision and accuracy studies. Limits of detection ranged from 0.2 to 5.8 ng g−1, limits of quantitation ranged from 0.66 to 19.2 ng g−1, and recoveries spanned 52.1–105.9% at the 100 ng mL−1 analyte level. Analysis of 12 unknown oyster composite samples revealed the detection of PFHxA, PFPeS, PFOA, PFHpA and PFOS and at least two compounds were detected in each oyster sample. This validated method proved to be an efficient and environmentally friendly sample preparation method for PFAS analysis in complex tissue media, such as oysters. [ABSTRACT FROM AUTHOR]

Human bocavirus (HBoV) is an emerging pathogen causing gastroenteritis/respiratory tract infection. Shellfish has been implicated in foodborne HBoV dissemination. The present investigation aimed at synthesising shellfish-associated HBoV data. Shellfish-HBoV data were mined from public repositories using topic-specific algorithm. A total of 30 data sources was identified of which 5 were synthesised. The average HBoV positivity and sample-size was 12 ± 9.2 and 134.2 ± 113.6, respectively. HBoV was studied in mollusc with 3.7–83.3% crude prevalence. The pooled HBoV prevalence in shellfish was 9.2% (7.2–11.8; 5 studies) and 12.9% (1.8–53.9; 5 studies) in common-effects and random-effects model respectively, with 0.12–94.89% prediction interval (PI). Sensitivity analysis yielded 8.7% (6.7–11.2; PI = 1.99–29.48%) prevalence. HBoV1 and HBoV2 pooled prevalence in shellfish was 7.91% (1.61–31.09; 3 studies) and 12.52% (0.01–99.60; 3 studies), respectively. HBoV3 prevalence was reported in one single study as 6.96% (4.41–10.35). In conclusion, the present study revealed high HBoV prevalence in shellfish, signifying the need to characterise HBoV and subtypes circulating in non-mollusc shellfish. Furthermore, there is an urgent need to mitigate the food safety risk that may result from HBoV contaminated shellfish since shellfish-borne HBoV is not routinely assessed and might be underestimated at present. [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]

Shellfish aquaculture is a globally expanding industry, including in urban estuaries that support non‐breeding waterfowl. The effects of shellfish aquaculture on the spatial distribution of non‐breeding waterfowl, however, are poorly understood and depend on the ecology of waterfowl and cultivated shellfish species. We investigated how proximity to shellfish aquaculture influenced habitat selection and movement patterns of American black ducks (Anas rubripes) during the non‐breeding season (~Oct–May) in 2020–2023 in Rhode Island, USA. The extent to which proximity to aquaculture influenced habitat selection of black ducks depended on factors specific to individuals' primary non‐breeding sites, although proximity to aquaculture did not have biologically meaningful influences on black duck movement rates across all sites. Black ducks across sites consistently selected for areas better suited for aquaculture (i.e., areas of potential future development) relative to areas poorly suited for aquaculture (i.e., areas less likely to be developed). The continued expansion of aquaculture into preferred black duck habitats will increase black duck interactions with aquaculture and therefore should be considered in the decision‐making process for siting future aquaculture leases. Future studies should quantify the extent to which continued expansion of aquaculture in those preferred coastal habitats directly influences black ducks. [ABSTRACT FROM AUTHOR]

Introduction: Bivalve aquaculture has direct and indirect effects on plankton communities, which are highly sensitive to short-term (seasonal, interannual) and long-term climate changes, although how these dynamics alter aquaculture ecosystem interactions is poorly understood. Methods: We investigate seasonal patterns in plankton abundance and community structure spanning several size fractions from 0.2 µm up to 5 mm, in a deep aquaculture embayment in northeast Newfoundland, Canada. Results: Using flow cytometry and FlowCam imaging, we observed a clear seasonal relationship between fraction sizes driven by water column stratification (freshwater input, nutrient availability, light availability, water temperature). Plankton abundance decreased proportionally with increasing size fraction, aligning with size spectra theory. Within the bay, greater mesozooplankton abundance, and a greater relative abundance of copepods, was observed closest to the aquaculture lease. No significant spatial effect was observed for phytoplankton composition. Discussion: While the months of August to October showed statistically similar plankton composition and size distribution slopes (i.e., food chain efficiency) and could be used for interannual variability comparisons of plankton composition, sampling for longer periods could capture long-term phenological shifts in plankton abundance and composition. Conclusions provide guidance on optimal sampling to monitor and assess aquaculture pathways of effects. [ABSTRACT FROM AUTHOR]

Shellfish cultivation is a sustainable method of providing human food and can help remove large amounts of CO2 from the atmosphere. Over the last two decades, longline-based structures have dominated farming systems. So far, the innovative technologies for open-ocean shellfish farming remain stagnant and need to be developed. As such, this paper preliminarily studies the operation and survivability abilities of an innovative shellfish farm under extreme wave conditions. To that end, an efficient numerical scheme with a robust implicit finite element method is established. First, the numerical modeling of a single module of the shellfish farm is conducted and the numerical results are verified against physical model tests. Then, the numerical modeling is implemented in a full-scale shellfish farm containing nine floating rafts with suspended lantern nets in a 3×3 configuration exposed to extreme wave conditions. Different angles of wave attack and shellfish rafts with and without lantern nets are fully considered, allowing an assessment of the operation and survivability abilities of the shellfish farm under extreme wave conditions in various situations. The results highlight that the angle of wave attack significantly affected the energy absorption of the mooring system. Moreover, non-linear instability such as subharmonics, which existed in the motion dynamics, can be manipulated to avoid resonant motions. This study provides insights into the evaluation of the safety design of a shellfish farm at both operational and survivability levels. The numerical method can also model other advanced offshore marine structures with multi-modules, such as floating bridges, airports, and even floating energy islands. [ABSTRACT FROM AUTHOR]

Blooms of Alexandrium catenella threaten to disrupt subsistence, recreational, and commercial shellfish harvest in Alaska, as the paralytic shellfish toxins (PSTs) produced pose a serious public health risk and can lead to costly shutdowns for shellfish farmers. Current methods of PST detection in the region range from monitoring programs utilizing net tows to detect A. catenella to direct shellfish tissue testing via mouse bioassay (MBA) for commercial aquaculture harvest, as well as various optional testing methods for subsistence and recreational harvesters. The efficacy and feasibility of these methods vary, and they have not been directly compared in Southeast Alaska. In this study, we sought to assess and compare A. catenella and PST early detection methods to determine which can provide the most effective and accurate warning of A. catenella blooms or PST events. We found microscope counts to be variable and prone to missing lower numbers of A. catenella, which may be indicative of bloom formation. However, quantitative polymerase chain reaction (qPCR) significantly correlated with microscope counts and was able to effectively detect even low numbers of A. catenella on all sampling days. Paralytic shellfish toxin concentrations measured by enzyme‐linked immunosorbent assay and MBA significantly correlated with each other, qPCR, and some microscope counts. These results show that qPCR is an effective tool for both monitoring A. catenella and serving as a proxy for PSTs. Further work is needed to refine qPCR protocols in this system to provide bloom warnings on an actionable timescale for the aquaculture industry and other shellfish harvesters. Integr Environ Assess Manag 2024;20:2189–2202. © 2024 The Authors. Integrated Environmental Assessment and Management published by Wiley Periodicals LLC on behalf of Society of Environmental Toxicology & Chemistry (SETAC). This article has been contributed to by U.S. Government employees and their work is in the public domain in the USA. Key Points: The species‐specific quantitative polymerase chain reaction (qPCR) assay effectively detects Alexandrium catenella at numbers too low for other methods.A threshold of ~90 000 000 A. catenella qPCR copies per liter may indicate elevated paralytic shellfish toxins in Pacific oysters.Microscope counts of A. catenella cells are variable and miss low quantities.Enzyme‐linked immunosorbent assays detect elevated paralytic shellfish toxins, and correlate with approved testing methods. [ABSTRACT FROM AUTHOR]

Tropomyosin (TM), the major allergen in shellfish, is a common protein cause of allergenic diseases, hence a sensitive, efficient method for TM detection is urgently needed to protect allergy sufferers in food products. In this work, a novel fluorescent aptasensor for TM-sensitive detection based on DNA-templated silver nanoclusters (AgNCs) and catalytic hairpin assembly (CHA) was designed. With the rapid separation and enrichment of magnetic beads, the detection of TM was converted to the detection of cDNA (complementary DNA). Then the cDNA was utilized as the initiator to successfully trigger the CHA amplification technique, which ultimately formed double-stranded to induce high fluorescence signals by AgNCs. Specifically, the cDNA could trigger repeated cycles, which enabled signal amplification and enhanced aptasensor performance with an excellent linear relationship in a wide linear range from 0.1 to 50 μg/mL (R2 = 0.9967) and a desirable low detection limit of 0.0179 μg/mL. It is worth noting that the method was successfully validated with high specificity and stability for detecting processed shrimp products, implying great potential in the field of allergen assay. [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]

Biofloc technology is instrumental in improving growth performance and yield in shellfish aquaculture, while leading to enhanced water quality through maintaining the nutrients level within a safe range. More specifically, toxic nitrogenous wastes are converted into beneficial microbial biomass known as "biofloc", contributing to improve shellfish immune system. Among the various parameters affecting the efficiency of the process is the carbon source and C:N ratio. In light of these, the present work critically reviews the effects of biofloc systems on growth performance, immunity and diseases resistance in shellfish production. Moreover, it scrutinizes the microbial diversity and nutritional composition of biofloc. Then, the application of the technology in various shellfish cultures, including shrimp, freshwater prawn, crabs, crayfish, clam, and oyster, is presented. Overall, biofloc systems contribute to enhanced shellfish survival rate to the highest value of 96–100% for marine shrimp, 95–99% for freshwater prawn, 70–83% for crayfish, 83–100% for oyster, Crassostrea sp. and up to 2% for mud crabs larvae through substantially reducing the ammonia level in the culture (summarized in Table 1 – Table 5). Finally, the main challenges in utilizing biofloc systems, i.e., suitable aeration and mixing and microbial mechanisms involved are also explained to shed light on future research directions in the field. [ABSTRACT FROM AUTHOR]

Dredge is the dominant shellfish fishing gear in Sedati District, this tool has good productivity in the shellfish fishing business. The productivity of fishing gear is related to the ability of fishing gear to provide better catches and the profits obtained by fishermen. This research aims to analyze business finances and the feasibility of shellfish fishing using fishing gear in Sedati Waters, Sidoarjo, East Java, Indonesia. This research used a survey research method with Primary and Secondary data. The samples collected from this study were spread across 224 respondents. The hauling process is carried out while catching shellfish 100-150 times. Shellfish fishing activities are carried out 20-26 days a month. The research results show that the average investment cost for a shellfish fishing business is IDR 31,340,000, fixed costs are IDR 6,988,973 and variable costs are IDR 26,600,000. The shellfish catch obtained by fishermen in one year is around 158 kg - 302 kg, with an average per fisherman of 226 kg consisting of Anadara antiquata, Anadara granosa, and Paratape undulatus batik with a total of IDR 68,380,000. The Net Present Value (NPV) value for the clam fishing business was IDR 75,607,420.00, IRR 72.66%, B/C Ratio 1.39, and the Payback Period was 1.64. By addressing these financial factors, a clam harvesting operation with dredging equipment can be efficiently planned and conducted, ensuring both economic feasibility and operational success. [ABSTRACT FROM AUTHOR]

We analyze costs, break-even prices, and profits for multiple scales of operation of an off-bottom oyster culture operation, ranging from 27,000 oysters planted on half an acre to 1.28 million oysters planted on four acres. The analysis focuses on the first five years of operation and accounts for factors such as operation startup, periodic adverse environmental conditions, variations in stocking and mortality rates, method of sale, and price to grower. We estimate total annual cost, including depreciation and interest on invested capital, labor, fuel, seed, and other expenses, to range from approximately $50,000 to operate a single line of floating bags to approximately $250,000 to operate twenty-four lines. We estimate the five-year average break-even price to range from $2.57 per oyster for 40,000 oysters planted on half an acre, to $0.71 per oyster for 480,000 oysters planted on two acres, to $0.52 per oyster for 960,000 oysters planted on four acres. Consistent with previous findings, we find that the average small-scale operation is not expected to be profitable. We estimate that it is generally necessary to operate at or above levels of 720,000 oysters planted on three acres to realize a positive average annual profit. [ABSTRACT FROM AUTHOR]

Large-scale seaweed and shellfish aquaculture are increasingly being considered by policymakers as a source of food, animal feed and bioproducts for Europe. These aquacultures are generally thought to be low impact or even beneficial for marine ecosystems as they are 'extractive' -- i.e., growing passively on foodstuff already available in seawater, and with potential habitat provision, fisheries, climate mitigation and eutrophication mitigation benefits. At some scale however, over-extraction of nutrients or chlorophyll could potentially have a negative effect on natural systems. Understanding the likely impacts of aquaculture production at scale is important to identify when safe limits are being approached. Taking seaweed aquaculture as the primary focus, this work uses operational oceanographic model outputs to drive prognostic growth models to predict the likely optimal distribution of seaweed farms across European waters to meet different production scenarios. A novel nutrient transport scheme is then used to model the interacting 'footprints' of nutrient drawdown from aquaculture facilities to demonstrate the likely spatial impact of large-scale aquaculture. Evaluation of both seaweed and shellfish contributions to CO2 balance under large scale production, and the potential impact on fisheries are also considered. The study finds that the impact of intensive seaweed aquaculture on nutrient availability could be significant where many farms are placed close together; but at the regional/basin scale even the highest level of production considered does not significantly impact total nutrient budgets. Seaweed aquaculture has the potential to extract large amounts of carbon dioxide, but the impact on carbon budgets depends on the end-use of the extracted seaweed. Shellfish aquaculture is a net source of CO2 due to the impact of calcification of shells on the carbonate system (i.e., alkalinity removal). However, gram-for-gram the CO2 impact of shellfish production is likely to be less than the impact of land-based meat production. Whilst operational oceanographic models are useful for taking a 'broad brush' approach to likely placement and impacts of aquaculture, reliable yield predictions for individual locations across European waters would require models integrating more physical and biogeochemical factors (wave environment, local currents, riverine inputs) at a finer scale than currently achievable. [ABSTRACT FROM AUTHOR]

BACKGROUND AND OBJECTIVES: The coastal area of Jeneponto Regency, South Sulawesi, Indonesia, is heavily impacted by microplastic pollution, which poses a threat to marine organisms such as shellfish and fish. This aim of this study was to identify the presence of microplastic polymers, including vinylidene chloride, polyacetylene, polychlorotrifluoroethylene, polybutylene terephthalate, poly(isobutyl methacrylate), cellulose acetate butyrate, polybutadiene, and polyvinylchloride, in shellfish and fish in the coastal area of Jeneponto district, Indonesia. METHODS: In total, 60 shellfish and fish samples were collected directly from 12 locations in the coastal waters of Jeneponto Regency. Sample preparation, including enzymatic digestion and mechanical destruction, was performed to separate the organic tissues of fish and shellfish into small particles. Optical microscopy (at 100x and 400x magnification) was used to observe the morphology and to count the number of particles per sample volume using a modified Neubeuer Improved Counting Chamber. Fourier-transform infrared spectroscopy was used to determine the type of polymer. FINDINGS: Feather clams contained the highest number of microplastics, with a total of 58 items ranging from 0.027 to 4.587 millimeters in size. The total abundance of microplastics in feather clams ranged from 0.25 to 2.14 items per gram. Kurisi fish contained 22 items ranging from 0.085 to 2.127 millimeters in size, with a total abundance ranging from 0.01 to 0.08 items per gram. The types of polymers identified in the fish and clams included vinylidene chloride, polyacetylene, polychlorotrifluoroethylene, polybutylene terephthalate, poly(isobutyl methacrylate), cellulose acetate butyrate, polybutadiene, and polyvinyl chloride. Vinylidene chloride was the predominant type of microplastic polymer, accounting for 42 percent of all microplastic polymers. CONCLUSION: This study successfully identified eight types of microplastic polymers found in shellfish and fish in the coastal area of Jeneponto; the most common was vinylidene chloride. These findings indicate that marine organisms and humans are exposed to microplastics, which are potentially harmful, but further research is needed to understand the full extent of the associated environmental health impacts and risks. [ABSTRACT FROM AUTHOR]

Diarrhetic shellfish poisoning (DSP) toxins and pectenotoxins (PTXs) produced by endemic species of Dinophysis, mainly D. acuta and D. acuminata, threaten public health and negatively impact the shellfish industry worldwide. Despite their socioeconomic impact, research on the environmental drivers of DSP outbreaks in the Chilean fjords is scanty. From 22 to 24 March 2017, high spatial–temporal resolution measurements taken in Puyuhuapi Fjord (Northern Patagonia) illustrated the short-term (hours, days) response of the main phytoplankton functional groups (diatoms and dinoflagellates including toxic Dinophysis species) to changes in water column structure. Results presented here highlight the almost instantaneous coupling between time–depth variation in density gradients, vertical shifts of the subsurface chlorophyll maximum, and its evolution to a buoyancy-driven thin layer (TL) of diatoms just below the pycnocline the first day. A second shallower TL of dinoflagellates, including Dinophysis acuta, was formed on the second day in a low-turbulence lens in the upper part of the pycnocline, co-occurring with the TL of diatoms. Estimates of in situ division rates of Dinophysis showed a moderate growth maximum, which did not coincide with the cell density max. This suggests that increased cell numbers resulted from cell entrainment of off-fjord populations combined with in situ growth. Toxin profiles of the net tow analyses mirrored the dominance of D. acuminata/D. acuta at the beginning/end of the sampling period. This paper provides information about biophysical interactions of phytoplankton, with a focus on Dinophysis species in a strongly stratified Patagonian fjord. Understanding these interactions is crucial to improv predictive models and early warning systems for toxic HABs in stratified systems. [ABSTRACT FROM AUTHOR]

A simple and reliable methodology for the detection of paralytic shellfish toxins (PSTs) in bivalve tissues using potentiometric chemical sensors was developed. Five methods of PST extraction from mussel and oyster tissues were evaluated, including the AOAC-recommended method, which served as the reference. The main objective was to minimize the matrix effect of the extracts on the sensors' responses and ensure efficient toxin recovery. Extraction procedures using acetic acid with heating and water yielded the highest responses from the potentiometric chemical sensors to PSTs. The highest recovery of PSTs from bivalve tissues was achieved with extraction using acetic acid and heating. Further extract purification, which is indispensable for liquid chromatography with fluorometric detection (LC-FLD) analysis, was found to be unnecessary for analysis with chemical sensors. While water extraction can also be used as a rapid and simple PST extraction method, the lower recoveries should be considered when interpreting the results. Further research is needed to identify the compounds remaining in the extracts that cause a decrease in sensor responses and to develop procedures for their elimination. [ABSTRACT FROM AUTHOR]

Introduction: Diarrhetic shellfish toxins (DST) harm shellfish aquaculture and endanger human health, and include well-known marine dinoflagellateproduced toxins such as okadaic acid (OA) and analogues, such as dinophysistoxin-1 (DTX-1). Toxin-producing species have different toxin profiles and contents, with unclear interactions, with the toxins hypothesized to be produced under stress conditions. Methods: Five morphotypes of Prorocentrum lima complex, a well-studied DSTproducing species with remarkable phylogenetic variability, were chosen and exposed to three distinct light conditions (photosynthetic active radiation, PAR; PAR+UVA; PAR+UVA and UVB) for 18 or 24 days. Results and discussion: The studied morphotypes were classified as either lightsensitive (LS) or light-tolerant (LT) types based on their light responses and varying abilities to produce DTX-1 across three orders of magnitude (0.001-1 pg cell-1 d-1, abbreviated as LL, ML, and HL in order of rank). All toxin production rates (Rtox) initially increased and then decreased, with the first peaks varying between days 3 to 12. The results of earlier peaks in LL and ML and a linear correlation between Rtox values for OA and DTX-1 in HL indicated that the two compounds may be competitive. When light conditions initially altered, Rtox was either stagnant or negative under all light treatments in the LS cohort, and with UV addition in LT, which subsequently delayed the early peaks. The Rtox data for DTX-1 all demonstrated earlier and higher peaks with UVA addition in LL and ML. Likewise, their growth was facilitated following the addition of UVA light. Therefore, Rtox of pre-peaks is relevant to photosynthetic status and photoprotection ability. As decreasing Rtox data points corresponded closely with phosphate depletion, the phosphate consumption rate was calculated and shown to be linearly or exponentially associated with all downward Rtox. This study proposes a supplydemand link between photosynthetic products and phosphate with DST biosynthesis, inferring a likely competitive interaction between OA and DTX-1 production. [ABSTRACT FROM AUTHOR]

Tetrodotoxin (TTX), which is found in various marine organisms, including pufferfish, shellfish, shrimp, crab, marine gastropods, and gobies, is an effective marine toxin and the cause of many seafood poisoning incidents. Owing to its toxicity and threat to public health, the development of simple, rapid, and efficient analytical methods to detect TTX in various food matrices has garnered increasing interest worldwide. Herein, we reviewed the structure and properties, origin and sources, toxicity and poisoning, and relevant legislative measures of TTX. Additionally, we have mainly reviewed the state-of-the-art progress of analytical methods for TTX detection in the past five years, such as bioassays, immunoassays, instrumental analysis, and biosensors, and summarized their advantages and limitations. Furthermore, this review provides an in-depth discussion of the most advanced biosensors, including cell-based biosensors, immunosensors, and aptasensors. Overall, this study provides useful insights into the future development and wide application of biosensors for TTX detection. [ABSTRACT FROM AUTHOR]

Shellfish aquaculture can provide important ecosystem services to coastal communities, yet these benefits are not typically considered within the aquaculture permit review process. Resource managers have expressed interest in easy-to-use tools, based on robust science, that produce location and operation-appropriate values for beneficial services. These values need to be produced in a format that aligns with existing regulatory processes to facilitate seamless integration with permit review. The removal of excess nitrogen from coastal waters by shellfish farms is well documented in the literature and has been incorporated into nutrient management in the USA. Shellfish assimilate nitrogen into their tissue and shell as they grow, and this nitrogen is removed from the environment upon harvest. We have assembled a dataset of nitrogen concentration and morphometric measurements from farmed eastern oysters across the US Northeast, and adapted methodology used by existing nutrient management programs to quantify harvest-associated removal of nitrogen. Variability in oyster tissue and shell nutrient concentration was low within the dataset, and an assessment of farm location, ploidy, and three common cultivation practices (floating gear, bottom gear, no gear) suggested that a simple regression-based calculation could be applied across all farms within the region. We designed the new, publicly available online Aquaculture Nutrient Removal Calculator tool https://connect.fisheries.noaa.gov/ANRC/ based on this analysis, which uses inputs related to oyster size and harvest number to predict harvest-based nitrogen removal from an eastern oyster farm located within the geographic range of North Carolina to Maine, USA. The tool also produces a report that has been designed to integrate with the US Army Corps of Engineers public interest review process, and similar state-level permitting processes, and provides a succinct summary of the ecological services associated with nutrient removal in eutrophic locations, project-specific values, and citations supporting the calculation of those values. [ABSTRACT FROM AUTHOR]

Vibrio parahaemolyticus is a leading cause of human gastroenteritis associated with seafood consumption. The present study aimed to investigate the occurrence and risk assessment of V. parahaemolyticus isolated from live Indian black clams, sediment, and water samples collected from shellfish harvesting areas located along the south-west coast of India. Out of the total 72 samples collected, 55.6% revealed the presence of V. parahaemolyticus; the highest occurrence was observed in shellfish samples. The presence of tdh and trh virulence genes was screened by multiplex PCR. Virulence genes could be detected in 25.8% of the strains; 19.35% of them were trh positive and 3.2% were tdh positive, while 3.2% of strains exhibited the coexistence of both virulence genes. Antimicrobial resistance (AMR) determined by the disk diffusion method revealed that 87% of the strains were multiple drug resistant and exhibited 21 diverse resistance patterns. The overall multiple antibiotic resistance (MAR) index values ranged from 0 to 0.8. To the best of our knowledge, this is the first report to document the presence of pathogenic and multidrug-resistant V. parahaemolyticus in shellfish harvesting areas of the Indian sub-continent. The study reveals possible health hazards associated with consuming shellfish harvested from the study area. [ABSTRACT FROM AUTHOR]

As climate change transforms marine environments globally, species distributions correspondingly shift to locations where conditions have become or remain favourable. The ability to model these distributional shifts has been facilitated by species distribution models (SDMs). However, current SDM approaches have largely ignored climate‐driven changes in species interactions, which ultimately can have an important influence on species distributions. In this study, we utilize a long‐term, large‐scale dataset spanning 48 years and approximately 30 degrees latitude across the Canadian Atlantic shelf. We examine how climate influences the distribution and predation patterns of two invertebrates, northern shrimp Pandalus borealis and snow crab Chionoecetes opilio, aiming to evaluate the impacts of climate change on prey distributions. We found that both invertebrate species have a pronounced predicted response to climate change, with a northern shift in the distribution of northern shrimp and an overall reduction in abundance of both snow crab and shrimp associated with warming temperatures. Including predatory interactions as predictors in the SDMs (either directly via predator densities or via estimated predation rates) improved prediction accuracy for northern shrimp but not for snow crab. This is consistent with the ecology of these two species, as northern shrimp is more vulnerable to predation than snow crab. We found that the projections of future northern shrimp distributions are sensitive to the predicted spatial distribution and abundance of predators, highlighting the inherent complexity of predicting species response to climate change. Collectively, these results contribute to a broader literature that seeks to improve the capabilities of models to predict the effects of species interactions on species distributions under changing ecological conditions. [ABSTRACT FROM AUTHOR]

The Sechelt inlet system (SIS), situated on the inner Sunshine Coast of British Columbia, lies within the territory of the shíshálh Nation. This study focuses on ∼1000 years of shíshálh shellfish harvesting from 930-0 cal. BP. Specifically, we investigated the seasonal timing of shellfish collection, relative shellfish harvesting pressure and paleo-temperature reconstruction at four archaeological sites. Thirty archaeological butter clam shells (Saxidomus gigantea) from the SIS underwent high-resolution shell oxygen isotope (δ18O) analysis and 662 individual archaeological shell fragments were analysed for growth stage determination. The δ18O results showed a pattern of year-round collection with an emphasis on spring collection at village sites. Results from shell growth stage analysis suggest an intensive pattern of shellfish harvesting in the region, regardless of the site type. Archaeological shells show a larger δ18Oshell range, possibly reflecting a greater sea surface temperature amplitude than modern shells (i.e. a difference of ∼6.5°C; modern range: ∼3.7–20.4°C; archaeological range: ∼ −0.8–22.4°C). We contextualise our results with previous studies of seasonal timing and intensity of shellfish harvesting from the Pacific Northwest Coast, while interpreting these new data in the context of shíshálh occupation and landscape use. [ABSTRACT FROM AUTHOR]

Within the framework of Ecosystem Approach to Aquaculture (EAA), ecological carrying capacity (ECC) is a key concept that helps to determine the upper limit of production without compromising ecosystem functioning. The implementation of ECC is complex as ECC differs between type of farms and location and standardised methods should be developed for management. There is therefore a clear need for operational indicators. The objectives of this paper were: (1) to carry out a systematic literature review on shellfish and seaweed aquaculture‐environment interactions to list the most used environmental indicators, (2) to classify the indicators according to the effects they measure (i.e., benthic, water quality, food web interactions, cultured organism health, resource use) and the scale at which they are applied, and (3) to assess their potential based on four indicator criteria categories: sensitivity, accuracy and precision, feasibility and utility, and ecosystem‐level scalability. Overall, indicators describing benthic effects were the most highly cited and scored. Indicators identified for bivalve and seaweed culture were discussed and compared to previous work on salmon aquaculture indicators to highlight similarities and differences across trophic levels. In addition, questions related to the challenges of ECC indicators implementation were presented to a panel of experts. The scoring and consultation provided the source of discussion on environmental management consistent with EAA. [ABSTRACT FROM AUTHOR]

Blooms of Gymnodinium catenatum have occurred occasionally in different areas of China and caused tremendous economic loss and even threatened human health. Not only is G. catenatum an important harmful-algal-bloom (HAB)-causing species, but also the only gymnodinioid dinoflagellate known to produce paralytic shellfish poisoning toxins (PSTs). Due to the germination of resting cysts, which often initiates blooms, the distribution and abundance of cysts in sediments and particularly the confirmation of cyst beds are important information for understanding and predicting dinoflagellate blooms. In this research, 199 sediment samples were collected from China's coastal seas, ranging from the Beidaihe in the Bohai Sea (BS) to the southernmost sample from the Nansha Islands of the South China Sea (SCS). TaqMan quantitative PCR (qPCR) assays with species-specific primers and probes were developed to specifically detect the distribution and abundance of cysts in the 199 samples. The detection revealed that G. catenatum cysts were widely present in the sediments (126 of the 199 samples), with 93.55%, 74.65%, 42.37%, and 50% of the samples detected positively from the BS, YS, ECS and SCS, respectively, and covering the vast sea area from Nansha Islands to the Beidaihe area. The single-cyst morpho-molecular identification in the samples from Beidaihe confirmed the existence of G. catenatum cysts in the BS, and the positive detections of G. catenatum cysts using the qPCR methods. While G. catenatum cysts were widely distributed in all four seas of China, the average abundance was relatively low (1.0 cyst per gram of wet sediment). Three samples from the East China Sea (ECS), however, contained G. catenatum cysts at a relatively higher level (23 cysts g−1 wet sediment) than other sea areas, suggesting a pertinence of cyst abundance to the frequent occurrences of G. catenatum blooms in the area during recent years. Collectively, for G. catenatum being such an important toxic and HAB-causing species globally, the ubiquitous distribution of its cysts along the coastal waters of China and higher abundance in the bloom-prone areas warns us of a risk that cyst beds, although currently low in abundance, may seed HABs in any and many sea areas of China at any forthcoming year, and particularly those areas with records of frequent HABs outbreaks in the past. [ABSTRACT FROM AUTHOR]

Long-term declines in coastal water quality and sedimentation can affect the restoration success of ecosystems such as seagrass and shellfish reefs. Resnagging coastal seascapes offers a potential alternative restoration method that is not reliant on abiotic conditions and which may enhance degraded landscapes for fish and fisheries. While common in freshwater ecosystems, such interventions are unusual for coastal seascapes despite log snags supporting significant benefits for coastal fish. In this study, we identify the spatial (e.g. seascape connectivity), habitat condition (e.g. log snag complexity and food availability) and water quality variables that best explain variation in fish assemblages on log snags to help prioritise the placement and design of resnagging efforts in estuaries. We surveyed fish assemblages on log snags using underwater videography at 363 sites across 13 estuaries in southeast Queensland, Australia, over 3 years. Sites less than 10,000 m from the estuary mouth, more than 2500 m from urban structures and located in water depths of < 3 m harboured more diverse fish assemblages. Sites less than 10,000 m from the estuary mouth with lower (< 25%) algae cover harboured greater total fish abundance and harvested fish abundance. Similar trends were found for the abundance of individuals from key functional groups, although these trends were mediated by other seascape contexts (e.g. the area of natural habitat) and water quality variables (e.g. chlorophyll-a concentration and dissolved oxygen saturation). Our results indicate that log snag placement in estuaries for benefits to fish and fisheries can be maximised if sites are planned strategically. [ABSTRACT FROM AUTHOR]

BACKGROUND AND OBJECTIVE: The coastal area of Jeneponto Regency, South Sulawesi, Indonesia, is heavily impacted by microplastic pollution, which poses a threat to marine organisms such as shellfish and fish. This aim of this study was to identifiy the presence of microplastic polymers, including vinylidene chloride, polyacetylene, polychlorotrifluoroethylene, polybutylene terephthalate, poly(isobutyl methacrylate), cellulose acetate butyrate, polybutadiene, and polyvinylchloride, in shellfish and fish in the coastal area of Jeneponto district, Indonesia.METHODS: In total, 60 shellfish and fish samples were collected directly from 12 locations in the coastal waters of Jeneponto Regency. Sample preparation, including enzymatic digestion and mechanical destruction, was performed to separate the organic tissues of fish and shellfish into small particles. Optical microscopy (at 100× and 400× magnification) was used to observe the morphology and to count the number of particles per sample volume using a modified Neubeuer Improved Counting Chamber. Fourier-transform infrared spectroscopy was used to determine the type of polymer.FINDING: Feather clams contained the highest number of microplastics, with a total of 58 items ranging from 0.027 to 4.587 millimeters in size. The total abundance of microplastics in feather clams ranged from 0.25 to 2.14 items per gram. Kurisi fish contained 22 items ranging from 0.085 to 2.127 millimeters in size, with a total abundance ranging from 0.01 to 0.08 items per gram. The types of polymers identified in the fish and clams included vinylidene chloride, polyacetylene, polychlorotrifluoroethylene, polybutylene terephthalate, poly(isobutyl methacrylate), cellulose acetate butyrate, polybutadiene, and polyvinyl chloride. Vinylidene chloride was the predominant type of microplastic polymer, accounting for 42 percent of all microplastic polymers.CONCLUSION: This study successfully identified eight types of microplastic polymers found in shellfish and fish in the coastal area of Jeneponto; the most common was vinylidene chloride. These findings indicate that marine organisms and humans are exposed to microplastics, which are potentially harmful, but further research is needed to understand the full extent of the associated environmental health impacts and risks.

Conservation efforts have raised awareness about the impact of small-scale fisheries on the distribution of seagrass plants. The patterns of recovery of the seagrass Zostera noltei and of the commercial bivalves Cerastoderma edule, Ruditapes decussatus and Ruditapes philippinarum after shellfish harvesting were studied in a field experiment in a shellfish bed in NW Spain. Sample plots were subjected to a single disturbance in two types of shellfish harvesting treatments in three zones characterized by different harvesting frequency and seagrass density. The photosynthetic efficiency (Fv/Fm), shoot density, leaf length and carbohydrate content of Z. noltei were monitored every three months during one year, and the C and N content of leaves and biomass of plants were measured one year after the disturbance. The abundance of adults, juveniles and recruits and the condition index of adult bivalves were quantified after the experimental harvesting. Shoot density and biomass of Z. noltei remained low during the ten months after the disturbance but recovered to control values after one year. Carbohydrate contents of apical rhizomes were lower in disturbed (treated) plots, whereas no effect was observed on Fv/Fm. Denser and more complex seagrass patches recovered faster. The abundance of adult bivalves below commercial size was lower in the disturbed plots, while the abundance of adults of commercial size, juveniles and recruits did not vary, indicating that abundance and condition were not hampered by harvesting pressure. The findings also suggest that Z. noltei meadows can recover within one year of the impact of shellfish harvesting if the harvesting areas are rotated and dense patches are preserved. [ABSTRACT FROM AUTHOR]

Abstract Background Shellfish reef restoration is relatively new in Australia, particularly to intertidal estuarine environments. In late 2019/early 2020 the first large-scale shellfish reef restoration project of the Sydney rock oyster, Saccostrea glomerata was undertaken in the Myall and Karuah Rivers, Port Stephens, on the mid north coast of New South Wales (NSW), Australia. The present study aimed to determine whether locally sourced clean conspecific oyster shells, and/or locally quarried rocks were better for natural recruitment of natural S. glomerata for large-scale oyster reef restoration, and subsequent recruitment of fishes and invertebrates. Over two years, recruitment of S. glomerata spat, and associated fishes and invertebrates were assessed on reefs made of: (1) rock, and (2) rock and shell. Results The mean (± SE) density of oyster spat on rock reefs (Myall River: 1790 ± 48, Karuah River: 1928 ± 68) was significantly greater (Myall River: ANOVA Si: MS 2, 18 = 31080167, F = 96.05, P

Paralytic shellfish toxins (PSTs) are a class of acute neurotoxins with nearly 60 congeners. Shellfish that filter feed on toxin-producing algae exhibit PST accumulation in tissues, and the consumption of toxic shellfish poses a major threat to human health. China has the largest aquaculture industry in the world, with shellfish production of approximately 15.89 million tons in 2022 and many shellfish consumers. The PST poisoning incidents in China exhibit the characteristics of a wide distribution area, recurring regional risk, diverse toxin sources, and seasonal differences. PST consumption causes acute symptoms of poisoning and even death in many people, with a high lethality rate. This is a serious threat to the health of consumers and detrimental to the social stability of the region. In northern China, Hebei Province has rich fisheries resources, with a mariculture output of approximately 580, 000 tons in 2022. In recent years, PSTs have been detected several times in bivalve shellfish inshore in Hebei Province, especially along the coast of Qinhuangdao. A serious shellfish poisoning episode was reported in Qinhuangdao in 2016, with PST concentrations exceeding the safety limit of 800 μgSTX equivalents/kg (μg STXeq/kg) by a factor of 65. The main algal species responsible for the poisoning was Alexandrium catenella. However, the current investigations of PST pollution in Hebei Province mainly focus on the shellfish species Mytilus galloprovincialis and Argopecten irradians in the sea area of Shanhaiguan, Qinhuangdao, and investigations on other coastal cities of Hebei Province and a wide range of different shellfish species are lacking. Moreover, few risk assessment studies have been conducted.A continuous PST survey was conducted in 2022 on six species of shellfish, namely M. galloprovincialis, Scapharca subcrenata, A. irradians, Scapharca broughtonii, Ruditapes philippinarum, and Crassostrea gigas, collected by netting in Tangshan and Qinhuangdao, and the residual status of PSTs was assessed for acute exposure using liquid chromatography-tandem mass spectrometry. The results showed that PSTs were detected in shellfish samples collected from March to June, with a detection rate of 100%. However, no values exceeded the European Union limit. Among the shellfish samples collected from March to June, those assessed in April had the highest average concentration, followed by those in May, March, and June, which had the lowest average concentration. The main components detected in shellfish samples from March to June were gonyautoxins (GTX) 1–4; the highest concentrations were detected in April. Highly toxic saxitoxin (STX) and decarbamoylneosaxitoxin (dcNEO) were detected from April to June and not in March. Decarbamoylgonyautoxin (dcGTX) 2 was not detected in March or April; however, it was detected in May and June. The sea area near Qinhuangdao was more polluted than that near Tangshan. Among the collected shellfish samples, significant differences were observed in the average concentration of PSTs in shellfish samples of different species, and the concentration ranged from highest to lowest in species as follows: M. galloprovincialis > S. subcrenata > A. irradians > S. broughtonii > R. philippinarum > C. gigas. Large differences were observed between the six shellfish species regarding the accumulation of 11 PST components, among which GTX1–4 and carbamatetoxin (C) 1 and 2 were the most commonly detected components. The highest concentrations of GTX1 and 4 were observed in M. galloprovincialis, the highest concentrations of GTX2 and 3 were observed in S. subcrenata, and the highest concentrations of C1 and 2 were observed in A. irradians. A low detection rate was recorded for highly toxic STX and neosaxitoxin (NEO in samples, except in M. galloprovincialis and S. subcrenata, in which all 11 PSTs were detected. In the other four shellfish species, only certain of the components were detected. Statistical analysis of the highest levels of PSTs in nearshore shellfish in Hebei Province in recent years showed a decreasing trend. Acute exposure assessments using the maximum value of PSTs showed that none of the six shellfish species exceeded the acute reference dose values recommended by the Food and Agriculture Organization of the United Nations/World Health Organization and European Food Safety Authority, suggesting that toxin levels were safe and acceptable. M. galloprovincialis had the highest dietary exposure risk, as a few residues were present, and symptoms of PST poisoning, such as dizziness and nausea, may occur after ingesting large quantities of M. galloprovincialis. Increased attention should be paid to shellfish with high dietary exposure assessment values, such as M. galloprovincialis and S. subcrenata.In this study, we investigated PSTs in shellfish from Hebei coastal waters and observed that PSTs were detected in shellfish samples from March to June, with the highest average concentration in April, followed by May and March, with the lowest average concentration in June. In addition, the main components detected in shellfish samples were GTX1–4. The analysis of different shellfish species showed that M. galloprovincialis had the highest average PST concentration, followed by S. subcrenata, A. irradians, S. broughtonii, R. philippinarum, and C. gigas; GTX1–4 and C1 and 2 were detected in all six shellfish species. Dietary exposure assessment for consumers in Hebei Province showed that the toxin levels were safe and acceptable. However, follow-up surveys and studies are necessary due to the paucity of surveys for different cities and species on the coast of Hebei.

The present review aimed to evaluate the current situation of pesticide residues detected in shrimp (commercial species) on the Mexican coasts. The organochlorine pesticides (OC), α-endosulfan (210.01 ng g−1), endosulfan sulfate (127.5 ng g−1), heptachlor (126.04 ng g−1 and γ-HCH (121.04 ng g−1) are identified as the most common pesticides in shrimp tissues, with the Northwest area reporting the highest concentrations of these OC. Given that there is an under-evaluation of pesticide residue levels, there was a greater contribution of studies directed at the Northwest of the country considering that there are states that are among the main shrimp-producing and consumers entities. The concentrations and types of pesticides banned nationally and globally, due to their toxic effects on the population, were reported. Therefore, since the most current information is 19 years out of date, it is necessary to perform recent evaluations with sensible and precise methods. [ABSTRACT FROM AUTHOR]

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

Global climate change has generated an increasing number of environmental problems, especially in Mediterranean coastal areas, such as the Po Delta (PD), where shellfish production has undergone an overall decline because of strong environmental changes. The present study is centred on assessing the fundamental ecological aspects in one of the most crucial European shellfish production lagoons, Sacca degli Scardovari (SC), addressing phytoplankton community parameters directly affecting shellfish production, namely, chemotaxonomic composition, size fractions, and total biomass, in relation to the physicochemical properties of the water column and mussel filtering activity. Our findings suggest that the phytoplankton community structure, its role within the lagoon food web and its production cycles depend on two distinct allogenic inputs, which shape the community differently and exert substantial control on shellfish production. At the same time, the suspended mussel biomass strongly controls the phytoplankton size composition, as their growth is largely supported by nanophytoplankton. As the Po River collects the drainage waters of the Italian side of the entire Alpine Arch, the phytoplankton dynamics reported here represent a useful baseline for further addressing issues of climatic changes affecting lagoon ecology. We believe that our study presents an innovative tool for the planning and management of interventions aimed at enhancing national mussel production without neglecting aspects of environmental protection or the integrity of the coastal system, with significant scientific implications. [ABSTRACT FROM AUTHOR]

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

Dakhla Bay, situated on the African Atlantic coast, has witnessed sporadic harmful algal blooms (HABs) caused by toxic dinoflagellate species over the past two decades. In this study, we investigated the distribution, abundance, and diversity of dinoflagellate cysts, with a focus on potentially toxic species that develop in this ecosystem where such data are lacking. Sediment samples were collected in April 2018 through coring at 49 stations distributed across the bay. The highest abundance of dinoflagellate cysts was recorded at 304 cysts/g dry sediment, observed at the inner part of the bay, indicating that this area is the preferential zone for cyst accumulation. Pearson's tests revealed significant positive correlations (P < 0.05) between cyst abundance and the water content, organic matter, and fine fraction (< 63 μm) of the sediment. Cyst morphotypes of potentially toxic dinoflagellate species known to produce saxitoxins, such as Alexandrium minutum, Alexandrium tamarense species complex, Gymnodinium catenatum, and yessotoxins, such as Lingulodinium polyedrum and Gonyaulax cf. spinifera, were identified in the sediment of Dakhla Bay. These findings were further supported by our long-term monitoring period (2005–2018), underscoring the presence of these HAB species in Dakhla Bay. During our survey, sporadic mollusk intoxication events were recorded at station PK25 for the grooved razor shell Solen marginatus and at station Boutelha for the oyster Crassostrea gigas. Paralytic shellfish toxin concentrations exceeded the sanitary threshold (80 μg STX di-HCl eq/100 g of shellfish meat) only twice, in December 2006 and January 2007 at station PK25. Contamination by amnesic shellfish toxins occurred sporadically but never reached the sanitary threshold of 20 µg/g of shellfish meat. Lipophilic shellfish intoxication occurred multiple times in the two investigated areas. These observations suggest that the cysts of the identified HAB species germinated and inoculated the water column, resulting in the observed intoxication events. Relatively low levels of intoxication could be attributed to the moderate abundances of cysts, which may reduce the seeding capacity. This could be explained by the significant interaction of Dakhla Bay with the Atlantic Ocean, characterized by hydrological dynamics that impede the deposition and accumulation of cysts in the bay's sediments. This study reaffirms the importance of investigating dinoflagellate cysts in assessing the diversity of HAB species and evaluating associated sanitary risks. [ABSTRACT FROM AUTHOR]

The distribution of trematodes Paracoenogonimus ovatus and its first intermediate hosts, viviparous Viviparus viviparus and V. contectus in the Ob–Irtysh basin were analyzed. Until the 1990s the spreading of P. ovatus in this region was associated with habitats of V. contectus, which is considered a native species in Western Siberia. Since the mid-1990s European species V. viviparus began to spread in the Ob basin. Before this, only one source of infection with P. ovatus was known associated with finding V. viviparus in the Lower Irtysh. This paper describes another such outbreak in the Tura River near the city of Tyumen. In fish from the Tura River, a generally high extent and intensity of invasion were noted. Further expansion of the range is predicted P. ovatus associated with expansion V. viviparus. [ABSTRACT FROM AUTHOR]

The hepatitis A virus (HAV) endemicity in the Philippines ranges from moderate to high. Despite this, health risks related to local seafood consumption are associated with red tide or mass fish kill. However, government agencies should consider the safety of local shellfish and culture sites to HAV. This article examines the current trends relevant to the presence of HAV along the local shellfish supply chain-including production levels, microbial concentration, consumer behavior, and food safety regulations. Despite the susceptibility of local shellfish to HAV, the study identified crucial data gaps: [1] reliance on bacterial indicators, [2] absence of monitoring records for HAV concentration in local shellfish products and culturing sites, and [3] limited studies regarding the effect of local cooking practices on HAV inactivation. The synthesis of this analysis will guide the national food safety risk managers in addressing the identified data gaps to facilitate a full-blown food risk analysis of HAV in Philippine shellfish. [ABSTRACT FROM AUTHOR]

Purpose: Fish and shellfish consumption is suggested to be a cancer-protective factor. However, studies investigating this association for gastric cancer, especially considering Helicobacter pylori (H. pylori) and atrophic gastritis (AG), are limited. We investigated gastric cancer risk associated with fish, shellfish, and n-3 polyunsaturated fatty acids (n-3 PUFAs) consumption among Japanese adults. Methods: 90,504 subjects enrolled in the Japan Public Health Center-based Prospective Study (JPHC Study) were followed until December 2013. Dietary intake data were collected using a food frequency questionnaire. Hazard ratios (HRs) and 95% confidence intervals (CIs) were calculated for gastric cancer risk associated with fish and shellfish consumption and marine n-3 PUFAs (sum of eicosapentaenoic acid (EPA), docosapentaenoic acid (DPA), and docosahexaenoic acid (DHA)) using Cox proportional hazards models. Among those with avaliable data, we conducted a subgroup analysis taking H. pylori infection and AG status into consideration. Results: There were 2,701 gastric cancer cases during an average of 15 years of follow-up. We observed an increased gastric cancer risk for salted fish consumption for men [HR for fifth quintile versus first quintile 1.43 (95% CI 1.18–1.75)] and for women [HR 1.33 (95% CI 1.00–1.77)]. We observed a weak risk reduction trend for women as the intake of marine n-3 PUFAs increased (p-trend:0.07). When we included H. pylori infection and atrophic gastritis status in the analysis, the associations diminished. Conclusion: Our results suggest that salted fish increases gastric cancer risk for men and women, while marine n-3 PUFAs marginally decreases this risk among women in Japan. [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]

Saxitoxin (STX), an exceptionally potent marine toxin for which no antidote is currently available, is produced by methanogens and cyanobacteria. This poses a significant threat to both shellfish aquaculture and human health. Consequently, the development of a rapid, highly sensitive STX detection method is of great significance. The objective of this research is to create a novel approach for identifying STX. Therefore, amplified luminescent proximity homogeneous assay (AlphaLISA) was established using a direct competition method based on the principles of fluorescence resonance energy transfer and antigen–antibody specific binding. This method is sensitive, rapid, performed without washing, easy to operate, and can detect 8–128 ng/mL of STX in only 10 min. The limit of detection achieved by this method is as low as 4.29 ng/mL with coefficients of variation for the intra-batch and inter-batch analyses ranging from 2.61% to 3.63% and from 7.67% to 8.30%, respectively. In conclusion, our study successfully establishes a simple yet sensitive, rapid, and accurate AlphaLISA method for the detection of STX which holds great potential in advancing research on marine biotoxins. [ABSTRACT FROM AUTHOR]

Marine ecosystems have been heavily contaminated in recent years by discharges from agricultural, domestic, chemical waste spills, ship emissions, etc. Among various pollutants, metals are considered the most serious ones, because they are not biodegradable and can show toxic effects on living organisms if exceeding certain concentration levels. In the present study, 24 biota species were randomly selected at the Vlora region, Albania and were analyzed for the content of some heavy metals in the edible part of their body. Except for Cd, the concentrations of heavy metals in the edible part of fish species did not exceed the permissible limits proposed by FAO (1983) and WHO (1996) and are suitable for human consumption. The estimated daily intake (EDI) of the selected species was lower than the daily reference intake (DRI) while low values of target hazard quotient (THQ < 1) had shown that the consumption of mussels containing heavy metals would not cause significant health risks to humans. Finally, studies of metal concentrations in coastal areas are relevant and useful for monitoring the health of environmental compartments, for the maintenance of biodiversity, and for assuring the quality of life, mainly for humans. [ABSTRACT FROM AUTHOR]

The article presents the discussion on regulatory challenges facing U.S. mariculture, highlighting the impact of permitting processes on industry growth and environmental protection. Topics include the evolution of shellfish aquaculture permitting since the O'Connell Report, the need for streamlined regulations to foster industry expansion; and the ongoing challenges in balancing regulatory efficiency with environmental concerns.

Shellfish waste with non-metallic fractions from waste printed circuit boards (D-NMFs and W-NMFs) were used to reinforce polypropylene (PP). Thermal stability and mechanical properties were investigated, supplemented by finite element analysis, to investigate the reinforcement mechanism. Thermal property studies revealed a significant strengthening of the PP matrix upon NMFs incorporation. Final decomposition temperature increased from 391ºC for pure PP to 415ºC and 420ºC with 15 wt.% NMFs, and further reached ~ 435ºC and ~ 430ºC with clam and crab shell. Regarding mechanical properties, NMFs inclusion, especially W-NMFs, significantly elevated the composites' stiffness. Tensile modulus, along with flexural strength and flexural modulus increased from 917.31 MPa, 33.02 MPa, and 509.24 MPa for pure PP to 1368.82 MPa, 54.95 MPa, and 1678.12 MPa, respectively, for composites with 15 wt.% W-NMFs. NMFs/PP composites filled with shells, especially clam shells, could further improve the filling effect. The tensile modulus, along with flexural strength, increased from 1379.04 MPa, 52.97 MPa, and 1103.49 MPa to 1579.05 MPa, 54.72 MPa, and 1918.96 MPa, respectively, for composites containing 10 wt.% W-NMFs and 15 wt.% clam shell. [ABSTRACT FROM AUTHOR]

Coastal shellfish aquaculture can influence benthic–pelagic-coupled systems because cultured species consume phytoplankton in the water column and return the captured organic matter and nutrients to the environment as biodeposits, which fall to the seafloor, affecting local sediment characteristics and the benthic community. In 2023, we conducted monthly field surveys to characterize the relationships between shellfish aquaculture and the surrounding environment by examining a range of physical and biological variables along the benthic–pelagic gradient at multiple sampling locations in relation to their distances from the aquaculture facilities in Onagawa Bay, Japan. The abundances of benthic macrofauna were dominated by polychaetes (86.3%), followed by gastropods (4.7%), malacostracans (2.7%), ophiuroids (2.1%), and bivalves (1.5%). Both benthic biomass and biodiversity were markedly higher, but the chlorophyll-a concentration of the water column and the sediment organic matter content were significantly lower at the closest proximity to the aquaculture facilities. Although the physical presence of shellfish aquaculture may effectively enhance pelagic–benthic energy fluxes, such processes may also pose a new challenge under the influence of recent global warming, causing widespread hypoxic conditions due to increased stratification in the water column accompanied by excess organic inputs from the aquaculture. [ABSTRACT FROM AUTHOR]

The ocean is the largest carbon sink on Earth and an important pathway to China achieving carbon neutrality. From a consumption perspective, studying the capacity of marine carbon sink in each of China's provinces and its interregional transfer is of great significance in harnessing the increase in ocean carbon sink driven by final demand. This article first calculates the productionside carbon sink in coastal provinces. Then, based on the 2007, 2012, 2015, and 2017 Chinese inter-regional input-output tables, each province's consumptionside marine carbon sink is calculated. The article further examines the influencing factors and key transfer paths for the growth of marine carbon sink through Structural Decomposition Analysis (SDA) and Structural Path Analysis (SPA) methods. The results show that each province's total consumption-side carbon sink continues to rise, with significant regional disparities, demonstrating a trend of higher carbon sink in coastal provinces than inland provinces. Among the nine coastal provinces, Hainan and Guangdong are in a net input state regarding carbon sink transfer, while the other seven are in a net output state. SDA results indicate that the carbon sink intensity effect and the consumption demand effect are important factors inhibiting and promoting carbon sink growth, respectively, while the influence of the input-output technical effect is weak and variable. SPA analysis reveals that carbon sink outputs are primarily transferred to the food and tobacco sector, the agricultural and forestry products and services sector, and the wood processing and furniture industry. The key transfer paths mostly occur within a province, with a relatively small proportion of interprovincial transfer paths. Based on the research findings, this article suggests steadily increasing the proportion of marine product consumption, actively expanding the value chain of shellfish and seaweed industries, continuously strengthening coordination between land and marine industries, and further promoting the domestic circulation of marine carbon sinks. [ABSTRACT FROM AUTHOR]

Simple Summary: Starfish are the natural enemies of shellfish. In many areas, especially in Qingdao, China, shellfish aquaculture has been adversely affected by starfish predation for many years, resulting in serious economic losses. To facilitate strategies for the protection of shellfish from starfish, this review analyzes the reasons for the proliferation of starfish and proposes governance suggestions for the control and utilization of starfish. Starfish are keystone species as predators in benthic ecosystems, but when population outbreaks occur, this can have devastating consequences ecologically. Furthermore, starfish outbreaks and invasions can have adverse impact economically by impacting shellfish aquaculture. For example, an infestation of starfish in Qingdao led to a 50% reduction in sea cucumber production and an 80% reduction in scallop production, resulting in an economic loss of approximately RMB 100 million to oyster and other shellfish industries. Addressing the imperative need to proactively mitigate starfish invasions requires comprehensive research on their behavior and the underlying mechanisms of outbreaks. This review scrutinizes the historical patterns of outbreaks among diverse starfish species across various regions, delineates the factors contributing to the proliferation of Asterias amurensis in Chinese waters, articulates preventive and remedial strategies, and outlines the potential for the sustainable utilization of starfish. [ABSTRACT FROM AUTHOR]

Shellfish remains are ubiquitous to coastal archaeological sites in the Marquesas but have seldom been the focus of dedicated investigations into their contribution to past diet and daily life. On the island of Ua Huka, in the northern group of the archipelago, people have consumed a variety of shellfish since their arrival on the island around the early 12th century AD. By analysing assemblages from five coastal sites spanning from the early settlement until the 18th century and using an archaeomalacological approach (precise taxonomic identification, coupled quantification methods, observation of taphonomic processes, biometry), we attempt to recount the exploitation processes of this resource, from the initial gathering stage to the final discarding of the shell. We further explore inter‐site and temporal variability in prey choice. Coupled with ethnographic accounts from European observers and insightful testimonies from current inhabitants of the island regarding present‐day practices, we highlight the persistence of choices regarding species selection, breakage patterns and cooking processes on an island that has seen major subsistence changes since European contact. [ABSTRACT FROM AUTHOR]

Aims Shellfish production areas are classified for suitability for human consumption using counts of Escherichia coli in shellfish samples. Two alternative laboratory methods are approved in the European Union and UK for measuring E. coli in shellfish samples; the most probable number (MPN) and pour plate methods. These methods have inherently different statistical uncertainty and may give different counts for the same sample. Using two approaches: simulated data and spiking experiments, we investigate the theoretical properties of the two methods to determine their reliability for shellfish waters classification. Methods and results Assuming a Poisson distribution of E. coli in shellfish samples, we simulate concentrations in 10   000 samples using the MPN and pour plate methods. We show that for higher concentrations of E. coli the pour plate method becomes increasingly more reliable than the MPN method. The MPN method has higher probabilities than pour plate of generating results exceeding shellfish classification thresholds, while conversely having higher probabilities of failing to detect counts that exceed regulatory thresholds. The theoretical analysis also demonstrates that the MPN method can produce genuine extreme outliers, even when E. coli are randomly distributed within the sampled material. A laboratory spiking experiment showed results consistent with the theoretical analysis, suggesting the Poisson assumption used in the theoretical analysis is reasonable. Conclusion The large differences in statistical properties between the pour plate and MPN methods should be taken into consideration in classifying shellfish beds, with the pour plate method being more reliable over the crucial range of E. coli concentrations used to determine class boundaries. [ABSTRACT FROM AUTHOR]