Search Results (58)

Background/Objectives: Non-indigenous species are increasingly reshaping Mediterranean marine ecosystems, particularly under ongoing climate warming. The rayed pearl oyster Pinctada radiata, a thermophilic species originating from the Indo-Pacific region, is one of the earliest and most successful invaders in the Mediterranean Sea and has recently established populations in the Adriatic Sea. Methods: This study integrates preliminary shell morphometric data with molecular genetic analyses based on mitochondrial cytochrome c oxidase subunit I (COI) and nuclear internal transcribed spacer 2 (ITS2) markers to confirm species identity and examine patterns of genetic variation in comparison with other Mediterranean Sea regions and the Persian Gulf. Results: Phylogenetic analyses based on COI confirmed P. radiata as a distinct and well-supported monophyletic lineage, whereas the nuclear ITS2 marker showed limited resolution and interspecific overlap. Mediterranean and Adriatic populations showed low COI haplotype and nucleotide diversity and weak genetic structuring, consistent with recent colonization and secondary expansion, whereas Persian Gulf populations were more genetically diverse. Conclusions: Future studies should employ larger sample sizes and broader geographic sampling across both the Mediterranean Sea and the full native range of P. radiata, combined with high-resolution genome-wide nuclear markers, to better resolve connectivity and invasion dynamics. Full article

Marine species with high fecundity and larvae with long-distance dispersal potential can have complex population genetic patterns. Characterizing population structure in these species is important for understanding their ecology and life history and designing management strategies. The eastern oyster (Crassostrea virginica) is both ecologically and economically important but has experienced recent population declines. Characterizing genetic variation in regional C. virginica populations will contribute to conservation and restoration practices. We used 20 nuclear microsatellite loci to examine genetic diversity, population structure, and kinship within and among wild oyster populations in coastal Georgia. Oysters were sampled from multiple fringe reefs within a single tidal creek and from four estuarine creeks spanning approximately 115 km of coastline. Genetic diversity was high across all sites, but modest yet significant population structure was detected at both local and regional scales. Within a single creek, significant genetic differentiation was observed among reefs separated by only a few kilometers. Kinship analyses revealed significantly higher relatedness within reefs and within creeks than among locations relative to random expectations. These results indicate that regional coastal dynamics, kin aggregation, local retention, and sweepstakes reproductive success contribute to fine-scale genetic structure despite high dispersal potential. Our findings suggest that accounting for local retention is important when designing oyster restoration, broodstock selection, and management strategies in dynamic estuarine and coastal environments. Full article

Genetic resources are becoming increasingly important in aquatic species, especially in sectors such as aquaculture and biomedical research. These advancements, however, lack standardized methodology to consistently improve efficient use of gametes for fertilization and to eliminate male variation during spawning. This study provides a conceptual basis for generalizable quality control in artificial spawning of aquatic species by using interdisciplinary, industrial-scale tools to calculate a fertilization unit (e.g., the amount of sperm required to reliably fertilize the eggs produced by a female). Blue catfish (Ictalurus furcatus), zebrafish (Danio rerio), and eastern oysters (Crassostrea virginica) were used as diverse representative species. Comparisons among aquatic species were reviewed, fertilization units were defined, and a sensitivity analysis was performed to assess how deviations from the fertilization unit could affect artificial spawning efficiency. Overall, reproductive strategy (e.g., gamete biology) and production setting significantly influenced the fertilization unit. Employing a fertilization unit decreased “wasted” sperm and reduced male variability during spawning. Furthermore, fertilization efficiency dropped significantly when sperm use strayed from the fertilization unit, declining with both underuse and overuse, especially in oysters and catfish. Standardizing gamete use in aquatic species is essential for economic planning and achieving commercial-scale production, especially when investing in selectively bred or cryopreserved sperm. Full article

With the historical and consistent population declines of the eastern oyster (Crassostrea virginica), restoration projects commonly deploy plastic bags (polyethylene) filled with recycled oyster cultch. Oyster cultch bags are utilized as material to stabilize sediment and provide a substrate for oyster larval recruitment, which provides a habitat for associated organisms and decreases marsh erosion. In addition to the plastic mesh bags utilized to contain oyster cultch, this study also utilized three different biodegradable oyster bag material types (biopolymer, basalt, and cellulose) to determine (1) the influence of bag type on oyster population dynamics, (2) bag durability over time (<1 year), and (3) the cost–benefits for each bag type, calculated via a Weighted Product Model (WPM), within a subsection of the West Galveston Bay Estuary, Texas. For bag type, the results suggested that plastic bags were the most resilient, followed by biopolymer, basalt, and cellulose bags. Plastic bags supported the highest oyster abundance and growth, demonstrating their effectiveness for establishing breakwater reefs. The WPM analysis indicated that plastic bags are inexpensive to deploy and, due to their longevity, are easily monitored over time. However, degradation of plastic bags may introduce microplastics into the environment, posing ingestion risks for bivalves. Whereas the nature-based solutions degraded quickly, inhibiting continuous monitoring, yet the loose cultch may facilitate the natural formation of reefs over time. The results highlight tradeoffs between maximizing oyster recruitment and growth, minimizing environmental contamination, and balancing ecological performance with material sustainability in oyster reef restoration practices. Full article

Nano- and microplastics (NMPs) in waterways reflect the impact of anthropogenic activities. This study examined spatial variations in the presence and types of NMPs in Galveston Bay (Texas, USA) surface waters and eastern oysters (Crassostrea virginica). The results reveal most MPs carried by surface waters are fibers > films > fragments. Up to 200 MPs were present in individual oysters [=1.88 (± 0.22 SE) per g wet weight]. Oyster health, based on condition index, varied spatially, but was not correlated with MP load. Based on attenuated total reflectance—Fourier-transform infrared spectroscopy, polyamide and polypropylene were frequently found in waters in the upper bay while ethylene propylene and polyethylene terephthalate were more common in the lower parts of the bay. Pyrolysis–gas chromatography–mass spectrometry revealed a very large range in concentrations of NMPs, from 28 to 10,925 µg ∑NMP/g wet weight (or 172 to 67,783 µg ∑NMP/g dry weight) in oysters. This chemical analysis revealed four main types of plastics present in oysters regardless of location: polypropylene, nylon 66, polyethylene and styrene butadiene rubber. Based on this finding, the average daily intake of NMPs estimated for adult humans is 0.85 ± 0.45 mg NMPs/Kg of body weight/day or a yearly intake of 310 ± 164 mg NMPs/Kg of body weight/year. These findings reveal higher body burdens of plastics in oysters are revealed by the chemical analysis relative to the traditional approach; this is not unexpected given the higher sensitivity and selectivity of mass spectrometry and inclusion of the nanoplastic particle range (i.e., <1 mm) in the sample preparation and analysis. Full article

The ecological restoration of oyster reef ecosystems enhances their ecological functions and strengthens carbon sequestration capacity in coastal zones. Identifying suitable restoration sites is a crucial prerequisite for initiating oyster reef restoration projects. This study developed an oyster reef restoration suitability index model for the Tianjin coast of Bohai Bay by integrating the Analytic Hierarchy Process (AHP) with the Geographic Information System (GIS). It was then applied to assess the region’s suitability for oyster reef restoration. The suitability analysis identified favorable environmental conditions for oyster reef restoration in most of the Tianjin coastal area, with high suitability for factors like dissolved oxygen, pH, and seabed slope. However, excessive water depth in the eastern bay mouth and strong currents in the southwestern region made these areas unsuitable. The northern and western coastal regions were deemed optimal restoration sites, while proximity to shipping lanes and industrial activities limited feasibility in some nearshore zones. The model outputs exhibited strong spatial concordance with existing oyster reef distributions, validating its predictive accuracy. This framework offers a robust foundation for oyster reef restoration planning, with an adaptable index system that allows for regional extrapolation. By leveraging this model, decision-makers can systematically evaluate site-specific restoration suitability, optimize resource allocation, and guide strategic conservation planning. Full article

Intertidal reefs comprised of the eastern oyster (Crassostrea virginica) are an important habitat type within the estuarine landscape and provide many unique ecosystem services. Within West Galveston Bay (WGB), Texas, this type of reef plays an important ecological role; however, the system’s intertidal reef abundance, structure, and habitat provisions are relatively understudied, and the current spatial extent of these reefs has not been recently quantified. The primary objectives of the study were to identify intertidal oyster reefs utilizing GIS models and sample representative reefs for topographical characteristics, oyster demographics, and the associated benthic macrofauna (ABM) community composition in WGB from August 2019 to February 2020. Secondarily, GIS models and oyster population abundance were utilized to estimate the intertidal oyster abundance in WBG. The total area of intertidal oyster reefs in WGB was estimated to be 818,128 m², with 59,931 m² of reefs confirmed through GIS analysis and ground truthing, and the GIS model estimating an additional 758,197 m² of reef. Through ground truthing, reefs were found to be either shell rakes, consisting of piled shell with minimal three-dimensional structure and oysters, or true intertidal reefs with high reef structure and oyster abundance. High oyster abundance was spatially distributed within the northeastern and southwestern areas of WGB and the total intertidal oyster population, coupling the GIS models and reef sampling, was estimated to be 500 million individual oysters. The ABM community was sparse in terms of richness and diversity, further indicating a lack of structural complexity in most of the reefs within this system. This study demonstrates the importance of coupling field results with GIS modeling to estimate system level population sizes and furthers the understanding of the spatial distributions of intertidal oyster reef to promote management, conservation, and restoration efforts. Full article

Here, we discuss the results of an experiment in toe-line protection of estuarine embankments from frequent slope failure using silt traps. We test the feasibility of terracotta rings to trap silt and promote natural mangrove regeneration in barren patches in front of embankments around human settlements in the Indian Sundarban region, designated as the Sundarban Biosphere Reserve. The initial results of the first sixteen months of observations, between May 2023 and August 2024, are encouraging. Sediment accumulation in the silt traps across sites ranges between 4 and 42 cm. Periodic granulometric analyses of sediments indicate that while the middle estuarine sites accumulate more clay/silt, the lower estuarine sites accumulate more sand. During the late and post-monsoon seasons, all sites except one, on the eastern coast of the lower estuarine island, exhibit natural mangrove regeneration, the main species being Porteresia coarctata, Sueda maritima and Avicennia marina. Additionally, oysters Saccostrea cuculata and occasionally Crassostrea cuttakensis are found attached to the terracotta silt traps. The results highlight the potential of the nature-based Living Shoreline strategy to support mangrove regeneration and toe-line protection cost-effectively. The study also successfully opens up new possibilities for sustainable elevation management in the sinking and shrinking mangrove region of the Sundarbans, a significant development in the face of climate change and accelerated sea level rise. Full article

Concerns about the health consequences of seafood-born human pathogens are ongoing given their occurrence, prevalence, and ability to cause infections, and sometimes death in humans as well as seafood-associated morbidity and mortality worldwide. An applied time-series (2000–2017) analysis of six reefs examined pathogen-specific annual trends and seasonal patterns in the eastern oyster, Crassostrea virginica, in Galveston Bay (Texas), a subtropical estuary in the Gulf of Mexico. Pearson correlation coefficients showed that temperature had a strong positive correlation with Vibrio vulnificus and V. parahaemolyticus (r = 0.66 and 0.51), but not the pathogenic thermostable direct hemolysin (tdh+) V. parahaemolyticus (r = 0.12). The correlations between Vibrio spp. and salinity showed the opposite trend. A cross-correlation factor analysis revealed the strongest positive correlations (r = 0.41 and r = 0.36, respectively) for high densities of V. vulnificus during high Perkinsus marinus infections with short lags (up to 1 month); this was not the case for total or tdh+ V. parahaemolyticus. These results reveal some of the complexity of interannual and long-term patterns of pathogens in oysters. Given climate change impacts and a growing aquaculture industry, examinations of oyster microbiomes in response to environmental and water quality variables are needed. Full article

Mushrooms are indeed gaining attention for their unique therapeutic and nutritional qualities, especially in fermented drinks. This trend builds on their historical use in traditional medicine, especially within Eastern practices, where mushrooms like reishi, chaga, shiitake, oyster, lion’s mane, and cordyceps are known for their immune-boosting, anti-inflammatory, and adaptogenic properties. This narrative review highlights the growing interest in the use of mushrooms as functional ingredients in fermented beverages, emphasizing their technological and functional advantages. Fermentation significantly enhances the nutritional content and bioavailability of mushrooms, making it an ideal method to maximize the health benefits and sensory appeal of mushroom-based beverages. Microbial activity breaks down complex compounds in mushrooms, making their bioactive components more accessible for absorption; bringing unique flavors, aromas, and textures; and creating a rich-sensory experience while offering potential health benefits. Mushrooms can also improve the stability and shelf life of fermented beverages due to the presence of antimicrobial and antioxidant compounds, adding another valuable benefit to their use in functional beverages. However, despite their potential, further research is needed to fully understand their impact on health and to refine production techniques for optimal quality and consistency. This review provides a comprehensive overview of the current knowledge of mushroom-fermented beverages, highlighting both the known benefits and research gaps that require further investigation. Given the early stage of this field, the review emphasizes the importance of the additional investigation to unlock the full potential of mushrooms in functional beverage applications. Full article

With so many studies today on the water quality of the sea, one can hardly comprehend the multitude of topics that arise all over the world. This study provides a few graphic syntheses related to the most frequent words (including their clustering and links), trend topics, the spatial distribution of the researched areas, and the thematic evolution of the research directions over the decades. The most frequent authors’ keywords have a 50% similitude between the ocean studies and the studies related to the Mediterranean Sea; these keywords are part of a causal chain that dominates the marine studies on water quality: nutrients → eutrophication → phytoplankton → chlorophyll → seagrass. The most frequent words in the titles and abstracts of the selected papers from the Web of Science are “concentration” and “species”; in the Mediterranean studies, “chlorophyll” and “temperature” are the most frequent. In close connection with water quality, Zostera marina (eelgrass) and Crassotrea virginica (eastern oyster) prevail at the global scale, while Posidonia oceanica (Neptune grass) is relevant in the Mediterranean space. Some of the most studied water bodies are the South China Sea, San Francisco Bay, Chesapeake Bay, and, in the Mediterranean Sea, the Adriatic, Ionian, Aegean, and Marmara seas. “Climate change” and “remote sensing” are trend topics that shape the current studies on water quality; the increasing sea surface temperature enhances algal blooms—these need to be monitored using satellite imagery for the sustainable evolution of human activities, including aquaculture. Full article

Shifts from saltmarsh to mangroves are well-documented at mangrove poleward boundaries. A regime shift from intertidal oyster (Crassostrea virginica) reefs to mangrove islands has recently been documented in transitional phases in Florida, USA. To understand the local drivers of an oyster/mangrove regime shift and potential tipping points leading to a permanent mangrove state, we tracked all mangrove propagules (n = 1681) across 15 intertidal oyster reefs with or without adult mangroves for 15 months in Mosquito Lagoon, FL. While no propagule bottleneck was observed, few (3.2%) mangrove propagules/seedlings survived on reefs with no prior encroachment, compared to 11.3% and 16.1% on reefs with established older (pre-1943) or newer (1943 to present) adult mangrove stands, respectively. In total, 90.6% of the arriving propagules were from the red mangrove Rhizophora mangle; 13.2% of these were alive at the end of this study. Survival was <1% for black (Avicenna germinans) and 0% for white (Laguncularia racemosa) mangroves. Factors that promoted red mangrove success included close proximity (≤0.3 m) to adult mangroves, especially black mangroves; partial, upright burial of propagules in sediment; and arrival on reefs after annual high-water season. Additionally, once reefs had 50% mangrove cover, the density of red mangrove seedlings increased from 0.04 to 0.46 individuals m⁻². Although climate change has alleviated the impact of extreme freezes on mangroves, local factors determine whether the regime shift will be complete and permanent; positive feedback loops associated with established mangroves suggest mangrove recruitment on intertidal oyster reefs will continue to increase. Full article

The Atlantic pearl oyster Pinctada radiata (Leach, 1814), the first documented Lessepsian bivalve species to enter the Mediterranean basin, is present in various coastal areas in Greece, and constitutes, almost exclusively, a domestic commercial bivalve resource. The present study aimed to contribute to the limited information available on P. radiata population structure and dynamics in Hellenic waters, especially following the recent enforcement of legislation for regulation of its fishery. A total of 703 individuals were collected using scuba diving from the South Evoikos Gulf. The male-to-female ratio (1:1.70) significantly departed from 1:1. A higher probability for female prevalence was exhibited for shell heights over 50.77 mm. Significant differences were exhibited in the shell height–total weight relationship between the sexes. The fourth-year class was the dominant cohort, comprising 50.09% of the population, out of the seven age classes identified. Asymptotic length was estimated at 109.1 mm and growth index at 3.35, respectively. Longevity was estimated at 15.7 years, with natural mortality (M) at 0.39 and total mortality (Z) at 0.76. The probability of capture (LC₅₀) was estimated at 50.72 mm at 2.8 years. Biological reference points F_MSY and E_MSY were higher than the fishing mortality and current exploitation rate, respectively, indicating the potential for further population exploitation. Full article

The Atlantic pearl oyster, Pinctada radiata (Leach, 1814), is an Indo-Pacific bivalve of the subtidal zone that has colonized habitats all over the Mediterranean. There is a lack of detailed information on the reproductive activity of P. radiata in Hellenic waters, especially following the recent amendment of national legislation aiming to regulate the fishery and prevent illegal fishing and trafficking as a substitute for indigenous oysters. A total of 703 individuals were collected by scuba diving from the southwest part of Evia Island. Gonad microscopic examination indicated that gametogenesis occurs from February to September, with a recovery stage in early autumn. Synchronicity occurs for both sexes, with temperature being the main controlling factor. The annual recruitment pattern indicated two prominent peaks of similar magnitude. Analysis of covariance indicated a significant temperature effect on gonad index above 22 degrees. Onset of sexual maturity (L₅₀) was estimated at 47.2 mm in shell height and 27.09 gr in total weight for the entire population. The sex ratio was in favor of females at 1:1.70, with 7% and 19% of the individuals assessed macroscopically and microscopically identified as hermaphrodites, respectively. Results offer valuable information for the management and conservation of pearl oyster populations. Full article

As some of the most threatened ecosystems in the world, the declining condition and coverage of coastal habitats results in the loss of the myriad ecosystem services they provide. Due to the variability in physical and biological characteristics across sites, it is imperative to increase location-based information to inform local management projects, which will potentially help to reestablish functions of coastal habitats. Since oysters are often used in restoration projects, this study quantified spatial and temporal patterns in eastern oyster spat settlement in a bar-built estuary in northeast Florida, USA that is host to a robust population of intertidal oyster reefs. Spat settlement was found to occur from April to October with small peaks in the spring and large ones around September. Inter-annual differences in spat settlement were likely influenced by existing environmental conditions and heavily affected by large-scale events such as tropical cyclones. Variations in regional spat settlements are possibly driven by the residence times of the watersheds, the density of adult populations, and the location of the spat collectors. The results of this study illustrate place-based variability in oyster settlement patterns and underscore the importance of local monitoring for oyster resource management, restoration, and research. Full article