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Simple Summary: The life cycle of marine benthic invertebrates includes a planktonic larval stage and a benthic adult stage, with larval settlement being the critical transition from a planktonic to a benthic lifestyle. Since adult mobility is limited or completely lost in the benthic environment, larval settlement directly affects population distribution, growth, and reproduction. Although larval settlement induced by natural chemical cues is widespread among marine invertebrates, the molecular mechanisms underlying this process remain unclear. Mytilopsis sallei, a typical marine fouling mussel, releases three purine compounds—adenosine, inosine, and hypoxanthine—that synergistically induce larval settlement. In this study, transcriptomic sequencing was employed to identify differentially expressed genes and signaling pathways associated with purine-compound-induced larval settlement. This research not only provides new insights into the molecular mechanisms of larval settlement in marine benthic invertebrates, but also offers a scientific basis and theoretical foundation for the ecological control of marine fouling organisms. The settlement of marine benthic invertebrate larvae is a crucial stage in their life cycle, directly influencing their population distribution, growth, and reproduction. It is generally believed that multiple chemical inducers in the environment synergistically affect larval settlement, though the underlying molecular mechanisms remain unclear. Our previous study has established that three purine compounds (adenosine, inosine, and hypoxanthine) released by adults of the mussel Mytilopsis sallei synergistically induced larval settlement. In this study, we performed transcriptomic sequencing analysis on larvae exposed to individual purine compounds and those exposed to a combination of three purine compounds. A total of 21,850 differentially expressed genes (DEGs) were identified. KEGG enrichment analysis of these DEGs revealed that the AMPK signaling pathway, FoxO signaling pathway, extracellular matrix (ECM)-receptor interaction, focal adhesion, and the thyroid hormone signaling pathway play key roles in the settlement of M. sallei larvae. Moreover, in larvae exposed to the combined action of three purines, the expression of relevant signaling pathways and metabolic processes was more significant. This research provides important information for understanding the molecular mechanisms underlying the induction of larval settlement in M. sallei by purine compounds in natural environments. [ABSTRACT FROM AUTHOR]

The depth culture influence (4, 8, and 16 m) and periods (upwelling and non-upwelling) on growth and survival of the pearl oyster Pinctada imbricata during 10 months in the southeastern Caribbean Sea (Cariaco Gulf) were evaluated. Monthly records were taken of survival, body growth, and fouling organisms of the pearl oyster, as well as weekly samples of the temperature, chlorophyll a, and seston of the water culture site. Monthly survival was above 92% at all depths. The variation in shell size and tissue mass of the oysters cultivated in the different depths showed a similar pattern, with slow growth during the non-upwelling period (June–October) and progressive growth during the upwelling period (November–April). The multivariate analysis showed that oyster growth was associated with the phytoplankton biomass at different depths, particularly during the upwelling period. Oysters at 4 m showed the greatest increases in all growth parameters, exceeding the minimum commercial size (50 mm) in 7 months. Hence, it is recommended that the culture of P. imbricata in the Gulf of Cariaco be started right before the upwelling season to take advantage of the high amount of food available during this period. It is also recommended that the suspended culture should not exceed 8 m for higher growth performance. [ABSTRACT FROM AUTHOR]

Coral restoration plays a pivotal role in mitigating the decline of coral reefs, increasing the need for implementing effective techniques and methodologies. This study investigates the efficacy of stocking Acropora muricata and Pocillopora grandis using fishing line versus rope in mid‐water floating nurseries, offering valuable insights for coral restoration practitioners. Over 1 year, survival, tissue cover, growth, cleaning time, cost, preparation, and stocking timing for both methods were evaluated. Fishing line reduced contact with fouling organisms, contributing to enhanced coral tissue cover and growth rates for P. grandis compared to rope, but no significant effect was detected for A. muricata. Survival differed among species, with higher rates for P. grandis compared to A. muricata, indicating no impact due to stocking methods but species‐specific differences. Challenges like nursery collapses and amphipod outbreaks may have impacted survival, emphasizing the importance of consistent maintenance and accessibility of project sites. Furthermore, the fishing line method reduced cleaning effort. However, cost considerations and preparation complexities for fishing line warrant careful evaluation, particularly with regards to project budgets. The study underscores the necessity for further research, incorporating diverse genotypes, species, and initial fragment sizes to refine restoration strategies. In summary, this study provides important guidance for coral restoration practitioners, aiding informed decisions on stocking methods for different projects and species while considering the balance between coral health benefits and operational feasibility. [ABSTRACT FROM AUTHOR]

Marine ranching is a fishery model that can improve the ecological environment of sea areas, increase and conserve fishery resources, and realize the sustainable utilization of fishery resources. It is widely used worldwide. In Shandong Province, marine ranching is divided into the following types: Reef casting, game fishing, bottom seeding, pastoral, and equipment, based on the production mode. Among them, pastoral marine ranching refers to marine ranching dominated by three-dimensional ecological aspects such as raft culture facilities.Raft culture facilities are a culture framework that must be constructed for the culture of bivalves such as oysters, scallops, and mussels in China's coastal waters. These facilities include six parts: a wooden pile, pursed rope, float, suspended cage, suspended rope, and floating rope. In the process of bivalve culture, the construction of a raft culture facility provides a good adhesion substrate for other organisms in the ocean, and a large number of fouling organisms will inhabit and survive on the culture facility. The activity of these fouling organisms will soften the raft culture facility and shorten the service life of the raft culture facility. Furthermore, the fouling organisms can plug the mesh, leading to the death of the farmed shellfish due to lack of oxygen, causing economic losses. However, relevant studies have also shown that the presence of fouling organisms can accelerate the rate of nutrient salt exchange between suspended organisms and aquaculture waters, which can promote the growth of phytoplankton, improve primary productivity, provide more bait for bivalve culture, and increase the fertility of bivalve culture, which is beneficial to bivalve culture. There are differences in the relationship between the fouling organisms' species number and biomass and environmental factors across different raft aquaculture areas. Therefore, basic research must be conducted on fouling organisms in raft culture areas to provide reference for healthy bivalve culture and further provide basic data for exploring the impact of fouling organisms on the ecological environment in raft culture facilities.To explore the seasonal changes of fouling organisms in raft culture facilities of pastoral marine ranching and their relationship with environmental factors, a 4-quarter survey was performed in the pastoral marine ranching area of Rushan Huaxin Foodstuffs Co., Ltd., from July 2022 to April 2023. A total of four fixed stations were set up in the raft culture area of oysters for each survey. The fouling organisms were investigated at each station. An area of 10 cm × 10 cm in the float, a length of 30 cm of the floating rope, and an area of 20 cm × 20 cm in the suspended cage were sampled. The collected samples were bottled and numbered; then, the sample was fixed and stored in 5% formaldehyde solution, and returned to the laboratory for species identification and counting. The species, biomass, diversity, dominant species, and community structure of the fouling organisms at three different sampling sites were analyzed, and the relationship between environmental factors and dominant species was determined by redundancy analysis (RDA) and Spearman analysis.The results showed that 35 species of fouling organisms were found in eight categories, including 13 species of Crustacea, 8 species of Mollusca, 4 species of Polychaeta, 3 species of Chordate, 2 species of Cnidaria and Phaeophyta, and 1 species each of Rhodophyta, Chlorophycophyta, and Echinodermata. There were significant seasonal variations in the community structure of fouling organisms. Furthermore, there were significant differences in the community structures of fouling organisms in suspended cages, floating ropes, and floats, and the biomass varied in the ranges of 31.48~1 645.82 g/m2, 23.22~580.76 g/m2, and 5.76~30.12 g/m2, respectively. The maximum biomass of fouling organisms appeared in summer. The richness index, evenness index, and diversity index of the fouling organisms ranged from 1.38 to 3.61, 0.33 to 0.92, and 0.88 to 2.58, respectively. The lowest richness index was observed on the summer float, the lowest evenness index and diversity index were observed on the summer suspended cage, and the three indexes reached the highest values on the spring suspended cage. The dominant species of fouling organisms belonged to the phyla Crustacea and Mollusca. Mytilus edulis was the dominant species on the floating ropes and suspended cages, and Caprella aino was the dominant species on the floats. The dominant species of fouling organisms in the float showed obvious seasonal changes. The dominant species on the float in summer was Perinereis aibuhitensis, and that in autumn was Crassostrea gigas. Gracilaria vermiculophylla was the dominant species on the float in winter and spring. The RDA results of dominant species and environmental factors showed that transparency, temperature, silicate levels, and chlorophyll were the main environmental factors affecting the community structure of fouling organisms, and the correlation between different species and environmental factors was also different. In this study, the seasonal variation of fouling organisms and their relationship with environmental factors were investigated in the Rushan oyster raft culture facility, and our results can provide reference for healthy oyster culture in this area.

Ultrasonic technology has drawn extensive interests for its great potential in marine antifouling applications. However, its effects on the adhesion behavior of marine fouling organisms on marine structures remain underexplored. This work investigated how ultrasonic treatment impacted the adhesion of Pseudoalteromonas on a gel-like marine epoxy primer. And the process parameters for ultrasonic treatment were optimized using response surface analysis with Design-Expert software 11. The results revealed that ultrasonic treatment disrupted the cellular structure of Pseudoalteromonas, causing the deformation and fragmentation of the cell membrane, leading to bacterial death. Additionally, ultrasonic treatment reduced the particle size and Zeta potential value of Pseudoalteromonas, which disrupted the stability of bacterial suspensions. It also increased the relative surface hydrophobicity of Pseudoalteromonas cells, resulting in a reduction in adhesion to the gel-like marine epoxy primer. This study demonstrated that ultrasonic treatment significantly disturbed the adhesion behavior of microorganisms like Pseudoalteromonas on the gel-like marine epoxy primer, which provided an effective approach for controlling marine biofouling. [ABSTRACT FROM AUTHOR]

This present study has been designed to develop an Antifouling agent to minimize the attachment of fouling organisms on the submerged substratum. In order to analyze the leaf extracts of reputable species, such as Ipomoea pescaprae, (sand dune plants) and Sesuvium portulacastrum, Batis maritima (salt marsh), an attempt was undertaken. Methanolic extracts of three plants were screened for antifouling activity against six marine fouling bacteria (Proteus mirabilis, Proteus vulgaris, Pseudomonas sp., Vibrio sp., Staphylococcus aureus, Escherichia coli) using disc diffusion method where the methanolic extract of Ipomea pes caprae exhibited a maximum zone of inhibition (26mm) against Pseudomonas sp. Further, the minimum inhibitory concentration assay was performed to determine the lowest effective concentration to inhibit microbial growth. Hence, the result has suggested Ipomea pes-caprae has a maximum inhibitory percentage (51%) in a lower concentration (100µL) against E. coli. To detect the functional groups in three extracts, FTIR was carried out, where Amine, Secondary Alcohol, Alkane and Amine salt all are commonly present in these three samples. A field study has been designed to evaluate the antifouling efficiency of three samples, where the commercial paint was formulated using methanolic extracts from three different plants. Thus, resulted in Sample-1 (Ipomea pes-caprae) has good bioactivity towards fouling organisms and resulted in less percentage of fouling formation (Wood-10%, Aluminium-22% and Fiber sheet-26%) in this field study. [ABSTRACT FROM AUTHOR]

Herein, inspired by the macrophage's defensive behavior of releasing free radicals to kill bacteria and viruses, a marine antifouling coating with dynamic surfaces is prepared by precise regulation of dynamic covalent bonds. Alkyl radical (R·) derived from oxime-urethane structure attracts and disrupts microbe cell membrane and pili between intimate cells, resulting in excellent anti-biofouling effect. Moreover, the newly exposed coating then continues to break, which ultimately results in the peeling of the layers, thus making barnacles, mussels and other fouling organisms less likely to adhere. [Display omitted] • Macrophage-inspired marine antifouling coating with dynamic surfaces is prepared. • Alkyl radical (R·) derived from oxime-urethane structure offers excellent anti-fouling performance. • The newly exposed coating continues to break making it less likely that fouling organisms will adhere to it. • This study presents a novel methodology for fulfilling the technological gap of marine coatings with dynamic surface. Macrophages can kill bacteria and viruses by releasing free radicals, which provides a possible approach to construct antifouling coatings with dynamic surfaces that release free radicals if the breaking of dynamic covalent bonds is precisely regulated. Herein, inspired by the defensive behavior of macrophages of releasing free radicals to kill bacteria and viruses, a marine antifouling coating composed of polyurethane incorporating dimethylglyoxime (PU x -DMG) is prepared by precise regulation of dynamic oxime-urethane covalent bonds. The obtained alkyl radical (R·) derived from the cleavage of the oxime-urethane bonds manages to effectively suppress the attachment of marine biofouling. Moreover, the intrinsic dynamic surface makes it difficult for biofouling to adhere and ultimately achieves sustainable antifouling property. Notably, the PU 50 -DMG coating not only presents efficient antibacterial and antialgae properties, but also prevents macroorganisms from settling in the sea for up to 4 months. This provides a pioneer broad-spectrum strategy to explore the marine antifouling coatings. [ABSTRACT FROM AUTHOR]

This article discusses the resurgence of the invasive polychaete species Ficopomatus enigmaticus in the Caspian Sea. The Caspian Sea has been affected by natural and human activities, resulting in the introduction of non-native species. F. enigmaticus, which was introduced from the Black Sea and the Sea of Azov in the mid-20th century, is one of eight polychaete species found in the Caspian Sea. The presence of F. enigmaticus has ecological and economic impacts, as it can alter habitats and food webs. The study reports the first resurgence of F. enigmaticus in the southern coasts of the Caspian Sea, specifically in the Anzali Port and Caspian Port areas. The research collected samples from various stations to study the dynamics of the Caspian Sea ecosystem. The study found that F. enigmaticus established aggregations in the marina of Caspian Port, but not in Anzali port. Over time, the density of F. enigmaticus increased in the marina, covering the canal walls. The document also mentions the impact of F. enigmaticus on the local ecology, including its contribution to water purification and potential safety hazards for recreational users. The changing Caspian environment, such as declining sea levels, may create opportunities for new invasions of alien species like F. enigmaticus. [Extracted from the article]

Sediment toxicity testing with very hydrophobic organic chemicals (VHOCs) is challenging because of the chemicals' low aqueous solubilities and slow kinetics. The present study presents the results of experiments investigating whether the standard exposure duration of 28 days with benthic invertebrates is sufficient for VHOCs; above which concentrations in sediment VHOCs are present as "free phase," that is, crystals or non‐aqueous‐phase liquids (NAPLs); and whether it is possible to discriminate between actual VHOC toxicity and physical effects caused by NAPLs through fouling of the test organisms. The results suggest that the standard sediment toxicity test duration is sufficient for obtaining steady‐state VHOC concentrations in Hyalella azteca and Lumbriculus variegatus, provided that spiking and equilibration are performed properly (i.e., no free phase present). Under these conditions, transient (days 3–20) peak‐shaped toxicokinetics were observed, with steady‐state concentrations reached at approximately 28 days. The concentration above which NAPLs are present, the so‐called critical separate phase concentration (CSPC), was determined for several VHOCs by modeling and two experimental methods. Modeling resulted in unrealistic and variable data and therefore should be applied with caution. Experimentally determining CSPCs was successful and yielded values of approximately 1000 (400–2000) mg/kg dry weight, depending on the chemical. Finally, it was demonstrated that distinguishing actual toxicity from physical effects is possible by applying a well‐considered test setup, combining toxicity tests with multiple invertebrates (including Lumbriculus, which serves as a negative control for fouling); a broad test concentration range, preferably up to at least 30 000 mg/kg; and passive sampling to localize the CSPC. Applying this setup, false‐positive effects due to fouling, as well as false‐negative results due to testing at too low concentrations (trying to stay below the CSPC), can be avoided. Environ Toxicol Chem 2024;43:1728–1739. © 2023 The Authors. Environmental Toxicology and Chemistry published by Wiley Periodicals LLC on behalf of SETAC. [ABSTRACT FROM AUTHOR]

Ultrasound waves have been employed to control marine biofouling but their effects on fouling organisms remain poorly understood. This study investigated the influence of ultrasound waves on barnacle (Tetraclita stalactifera cyprid larvae) pre-settlement behavior. Substrate inspection constituted most of the larval time budget, with a focus on the bottom surface rather than lateral or air–water interfaces. The frequency of substrate inspection decreased at 10 kPa when compared to higher acoustic pressures, while the time spent in the water column had an opposite trend. Various larval swimming modes were observed, including rotating, sinking, walking, and cruising, with rotating being dominant. Barnacle larvae exhibited higher speeds and less complex trajectories when subjected to ultrasound in comparison to controls. The impact of ultrasound waves on barnacle cyprid larvae behavior had a non-linear pattern, with lower acoustic pressure (10 kPa) inducing more effective substrate rejection than higher (15 and 20 kPa) intensities. [ABSTRACT FROM AUTHOR]

Simple Summary: Marine biofouling is the undesirable accumulation of marine organisms onto man-made surfaces, which causes severe economical and environmental consequences. In recent years, using natural products as environmentally friendly antifouling agents to combat foulers has been a promising approach. However, the search for effective antifouling agents is hampered by the lack of well-defined conserved molecular targets responsible for regulating the larval settlement in fouling organisms. In this study, an in silico approach was used to screen the natural compounds' libraries against silk gland factor 1 (SGF1), which is responsible for the larval settlement of the fouling mussel Mytilopsis sallei. It was found that the targeted binding compounds against SGF1 could significantly affect the larval settlement, foot proteins' gene expression, and byssus secretion of adults in M. sallei. The laboratory bioassay results are promising, even though field trials are necessary to confirm the in silico results. Hence, this study paves the way for new experimental studies to be carried out for finding environmentally friendly antifouling agents by using SGF1-targeted compounds. Most fouling organisms have planktonic larval and benthic adult stages. Larval settlement, the planktonic–benthic transition, is the critical point when biofouling begins. However, our understanding of the molecular mechanisms of larval settlement is limited. In our previous studies, we identified that the AMP-activated protein kinase-silk gland factor 1 (AMPK-SGF1) pathway was involved in triggering the larval settlement in the fouling mussel M. sallei. In this study, to further confirm the pivotal role of SGF1, multiple targeted binding compounds of SGF1 were obtained using high-throughput virtual screening. It was found that the targeted binding compounds, such as NAD+ and atorvastatin, could significantly induce and inhibit the larval settlement, respectively. Furthermore, the qRT-PCR showed that the expression of the foot proteins' genes was significantly increased after the exposure to 10 μM NAD+, while the gene expression was significantly suppressed after the exposure to 10 μM atorvastatin. Additionally, the production of the byssus threads of the adults was significantly increased after the exposure to 10–20 μM of NAD+, while the production of the byssus threads was significantly decreased after the exposure to 10–50 μM of atorvastatin. This work will deepen our understanding of SGF1 in triggering the larval settlement in mussels and will provide insights into the potential targets for developing novel antifouling agents. [ABSTRACT FROM AUTHOR]

Multielectrode electrochemical biosensors promise on-the-spot inspection of target compounds in biofluids, reducing costs in personalized healthcare. However, sensor sensitivity may decrease after each use due to biofouling, where chemical attachments on sensor electrodes curtail sensing signals. Current biofouling characterization techniques rely on time-consuming offline tests and analysis, making them impractical for on-the-spot signal correction. Alternatively, we propose to statistically model and correct the biofouling-induced signal changes. However, in addition to biofouling, the signals are influenced by multiple sources of variation, each with different levels of impact. To effectively characterize and separate biofouling effects from the major sources of variability, we establish a multiresolution functional mixed-effect model based on domain knowledge. A biosensing signal is first decomposed into a smooth trend and local peaks. The smooth trend models the effects of population-level biofluid composition, as well as patient and electrode effects to isolate variability sources. Changes in local peak location and amplitude indicate biofouling. These local peaks are modeled using a sparse subset of high-order functional terms. By modeling the changes of those high-order terms, we can characterize and predict the biofouling between consecutive measurements. We propose a sequential parameter estimation procedure that ensures model identifiability. A nonparametric regression model is developed for biofouling prediction. The proposed strategy is validated through simulation and real case studies, effectively correcting biofouling-affected signals from new patients. [ABSTRACT FROM AUTHOR]

Microplastics (MPs) are insidious plastic particles with sizes ranging from 1 to 5000 µm. Their presence has been reported all over the world. Recently, bioremediation to remove MPs from water columns using filter feeders as biofilters has been proposed. In a previous lab experiment, the MP bioremediation potential of four fouling organisms from a mariculture facility (Mytilus galloprovincialis, Sabella spallanzanii, Phallusia mammillata, Paraleucilla magna) was separately assessed in single-species experiment. Herein, a follow-up of the work is presented using a multi-species approach. The four organisms were placed together in the same 5 L beaker and fed with a concentration of 250 p/L 6 µm red polystyrene discernible particles. After digesting the organisms and counting the MPs in both the water and the organisms, the results of the two experiments were compared. In the previous experiment, S. spallanzanii had the highest particle retention (PR) value (PR = 88.01%), while in this experiment, P. mammillata has the lowest PR value (PR = 31%). The multi-species approach resulted in a higher number of plastics being removed from the water (88%) compared to the single-species experiments. These fouling organisms naturally exist as a community, acting as an efficient filter with complex morphologies and hydrodynamic features. Here, this simple marine animal forest is re-evaluated by exploiting the ecosystem services provided by these organisms as a solution to MP pollution problem in a mariculture environment. [ABSTRACT FROM AUTHOR]

The port fouling fauna from Mexico has received greater study in the last 15 years. By improving our knowledge of fouling invertebrates on artificial substrates on the Southern Pacific coast of Mexico, we can better understand their distribution and prevent bioinvasions. The specimens listed in this present study come from PVC plates that were placed between June 2019 to June 2020 submerged at 1 m depth, on four docks of the Chahué Marina, Oaxaca, Mexico. Forty-four taxa, representing nine phyla were identi-fied: Sipuncula (1 species), Entoprocta (1), Bryozoa (3), Arthropoda (3), Porifera (4), Cnidaria (5), Chordata (6), Mollusca (10) and Annelida (11). Thirty taxa were identified to species, with two still requiring confirmation. Five were identified to genus, two to family, and five to class level. From the 30 identified species, 18 were non-native species: one entoproct, one mollusk, two bryozoans, three hydrozoans, three barnacles, four polychaetes, and four ascidians. These results include seven new records from the state of Oaxaca: one entoproct, one barnacle, two bryozoans, and three hydrozoans. [ABSTRACT FROM AUTHOR]

Purpose: The purpose of this paper is to study the correlation between different topographies and the reaction of Ulva Linza fouling species. Design/methodology/approach: In this research, topographies with a different method, such as hot embossing and hot pulling, were achieved, and biological analyses were done with macroalgae Ulva Linza cells. The effect of topography via local binding geometry (honeycomb size gradients) and Wenzel roughness on the settling of Ulva microorganisms was tested. Findings: As a result, Ulva spores confirmed different reactions to a similar set of tapered microstructures that was in agreement with the results on distinct honeycombs. The local binding geometry and the Wenzel roughness factor "r" were dominant on settling of Ulva Linza spores. Research limitations/implications: The reaction of an organism at the interface of vehicles' substrate is powerfully affected by surface topographies. Practical implications: The best embedment occurred on structures with bigger sizes than Ulva Linza's spores. The density of settled spores was proportional to Wenzel roughness and the spores favour to attach to "kink sites" positions. Social implications: Unfortunately, unpleasant aggregation of marine biofouling on marine vehicles' surfaces, generate terrific difficulties in the relevant industry. Originality/value: There was a sharp relationship between Wenzel roughness and settle of Ulva Linza spores. The local binding geometry and the Wenzel roughness factor "r" were dominant on settling of Ulva Linza spores. [ABSTRACT FROM AUTHOR]

A marine antifouling compound, N-octyl-2-hydroxybenzamide (OHBA), inspired by ceramide and paeonol molecules, was created. First, methyl salicylate was synthesized with salicylic acid and methanol, followed by n-octylamine through an ester-amine condensation reaction. Fourier transform infrared spectroscopy, nuclear magnetic resonance spectroscopy, and mass spectrometry confirmed the characteristic structure of the OHBA compound. Bioassays showed that OHBA inhibits the growth of typical marine fouling organisms, such as Vibrio azureus, Navicula subminuscula, Ulva pertusa, Mytilus edulis, and Amphibalanus amphitrite, indicating its broad-spectrum antifouling ability. A one-year marine real-sea test further demonstrated the excellent antifouling properties of OHBA. OHBA is also extremely biodegradable, with a half-life of 6.3 days, making it a less environmentally harmful replacement for widely-used heavy metal-containing antifoulants. [ABSTRACT FROM AUTHOR]

Eelgrass (Zostera marina) meadows and boat mooring fields co-occur in nearshore, relatively sheltered embayments. Traditional chain moorings create denuded scars in eelgrass meadows due to repeated and chronic scour of the seafloor by the chain, impacting meadow contiguity and quality. This study assessed the recovery of eelgrass into mooring scars following the conversion of traditional chain moorings to floating rode conservation mooring systems (CMS) in three Massachusetts harbors. The magnitude of eelgrass recovery following the conversion of 21 moorings to floating rode CMS was contingent on the location and positively correlated with the size of the scar associated with the mooring. While most scars started to revegetate following mooring conversion, few experienced complete recoveries and had a persistent denuded halo averaging 2 m in radius around the mooring anchors 5 years post-conversion. We observed CMS gear dragging on the bottom and impacting eelgrass when it was oversized for the depth of the site, and when it was not maintained or cleaned of fouling organisms. Overall, we show that floating rode CMS can be an important tool for eelgrass conservation; however, eelgrass recoveries following mooring conversion to floating rode CMS are variable and incomplete, and challenges pertaining to proper installation and long-term maintenance must be addressed to fully realize this potential. [ABSTRACT FROM AUTHOR]

Many female squids and cuttlefishes have a symbiotic reproductive organ called the accessory nidamental gland (ANG) that hosts a bacterial consortium involved with egg defense against pathogens and fouling organisms. While the ANG is found in multiple cephalopod families, little is known about the global microbial diversity of these ANG bacterial symbionts. We used 16S rRNA gene community analysis to characterize the ANG microbiome from different cephalopod species and assess the relationship between host and symbiont phylogenies. The ANG microbiome of 11 species of cephalopods from four families (superorder: Decapodiformes) that span seven geographic locations was characterized. Bacteria of class Alphaproteobacteria, Gammaproteobacteria, and Flavobacteriia were found in all species, yet analysis of amplicon sequence variants by multiple distance metrics revealed a significant difference between ANG microbiomes of cephalopod families (weighted/unweighted UniFrac, Bray–Curtis, P = 0.001). Despite being collected from widely disparate geographic locations, members of the family Sepiolidae (bobtail squid) shared many bacterial taxa including (~50%) Opitutae (Verrucomicrobia) and Ruegeria (Alphaproteobacteria) species. Furthermore, we tested for phylosymbiosis and found a positive correlation between host phylogenetic distance and bacterial community dissimilarity (Mantel test r = 0.7). These data suggest that closely related sepiolids select for distinct symbionts from similar bacterial taxa. Overall, the ANGs of different cephalopod species harbor distinct microbiomes and thus offer a diverse symbiont community to explore antimicrobial activity and other functional roles in host fitness. IMPORTANCE Many aquatic organisms recruit microbial symbionts from the environment that provide a variety of functions, including defense from pathogens. Some female cephalopods (squids, bobtail squids, and cuttlefish) have a reproductive organ called the accessory nidamental gland (ANG) that contains a bacterial consortium that protects eggs from pathogens. Despite the wide distribution of these cephalopods, whether they share similar microbiomes is unknown. Here, we studied the microbial diversity of the ANG in 11 species of cephalopods distributed over a broad geographic range and representing 15–120 million years of host divergence. The ANG microbiomes shared some bacterial taxa, but each cephalopod species had unique symbiotic members. Additionally, analysis of host–symbiont phylogenies suggests that the evolutionary histories of the partners have been important in shaping the ANG microbiome. This study advances our knowledge of cephalopod–bacteria relationships and provides a foundation to explore defensive symbionts in other systems. [ABSTRACT FROM AUTHOR]

Surface biofouling, corrosion, and wettability are important parameters to understand and characterize aluminum alloys to prevent the failure in marine environments. Antifouling technologies predominantly encompass chemical and biocidal approaches with negative environmental consequences. Therefore, this study focuses on a new method of producing non‐toxic and effective antifouling and corrosion‐resistant surfaces. In this study, ultrafast laser texturing is used to modify the surface of an aluminum alloy using a femtosecond laser system. Five different unique texture patterns are designed and fabricated using 3 W laser power, 100 kHz pulse repetition rate, and 4 mm s−1 scanning speed in order to make the aluminum surface antifouling and corrosion resistant. The non‐textured sample has a contact angle of 85° while the textured samples have contact angles of up to 157°. The contact angle increased with time up to 90 days of aging. Biofouling assessment is conducted using marine algae Nitzschia ovalis as a marine fouling test organism. A reduction of biofilm coverage of 79% is recorded from the laser‐produced star pattern texture. This study demonstrates that laser‐textured surfaces have the potential to mitigate the formation of biofilms on the surfaces while also providing a mechanism to control the relative level of corrosion. [ABSTRACT FROM AUTHOR]

Ethylene propylene diene elastomer (EPDM) harbors diverse microbiota that form biofilms. Such biofilms may contaminate water and can increase drag force impacting the hydrodynamic performance of a ship, once it is used as fenders. Here, the EPDM surface is modified by radiation‐assisted grafting to prevent biofilm formation. Three different monomers, namely, methacrylic acid (MAA), isodecyl methacrylate (IDM), and lauryl methacrylate (LMA), are grafted on EPDM. The modified surfaces are characterized by Fourier transform infrared (FTIR) spectroscopy, surface wettability, mechanical and dynamic mechanical properties (DMA), and scanning electron microscopy (SEM). The modified surfaces are subjected to biofouling by prominent biofilm adherents, that is, Pseudomonas aeruginosa and Klebsiella pneumoniae. The standard plate count and resazurin fluorescence assays are performed to observe the microbial load on these surfaces. The MAA‐grafted EPDM, which is hydrophilic in nature, shows a considerable decrease in bacterial adhesion compared to pure EPDM, but for IDM and LMA‐grafted EPDM, it is the opposite. The deterioration of the surface with bacteria by environmental scanning electron microscopy (ESEM) supports the findings. The tensile property of the modified EPDM is observed to be within satisfactory limits. After such modification, the EPDM is expected to expand its application. [ABSTRACT FROM AUTHOR]

This study reported the composition of the macrobenthic assemblage living on the shell of the pectinid scallop Mimachlamys sanguinea inhabiting the Suez Canal Expansion Channel. Nine epibiont groups were observed encrusting the valves of the scallop primarily serpulids, barnacles and tunicates (20.9, 15.5, and 14.8%, respectively). The upper valve was significantly more fouled than the lower one. A positive correlation was observed between the percent cover of fouling material and the shell size, with maximum percent cover and size occurring during the spring. The relationship between the scallop and its fouling organisms was discussed. The importance of M. sanguinea shells as a natural substratum for various epibiotic groups was highlighted in this study. [ABSTRACT FROM AUTHOR]

The purpose of this study is to describe fishermen's and managers' current awareness of International Maritime Organization (IMO) biofouling guidelines to improve biofouling management on all fishing vessel types in the northern Persian Gulf. A total of 234 in-depth and semi-structured interviews were conducted face-to-face with fishermen and managers using a random sampling technique from February to November 2021. Analyses of data indicated that the majority of industrial fishermen (87%) and all of managers were aware of the IMO biofouling guidelines, but traditional fishermen had a low level of awareness (38%) and they had also many problems such as increased cost, lack of training courses, lack of sufficient facilities for implementation of IMO biofouling guidelines. For industrial fishermen, literacy was a most effective variable on awareness of IMO guidelines (p ˂ 0.05, r = 1.62). As regulations to prevent invasions and the accumulation of biofouling in fishing gear and fleets, biofouling should be managed and evaluated, and also training should be provided to fishermen to clean the biofouling of fishing gear and fleets in accordance with IMO guidelines, as well as more monitoring by managers, environmentalists, the government, and policymakers. [ABSTRACT FROM AUTHOR]

Characterizing seasonal changes in diatom community profiles in coastal environments is scarce worldwide. Despite diatoms being prevalent in microfouling, their role in microbially influenced corrosion of metallic materials remains poorly understood. This study reports the effect of seasonal variations on the settlement of marine diatoms and corrosion of 316 L stainless steel surfaces exposed to Chilean coastal seawater. Electron microscopy imaging revealed a diverse assembly of diatoms, exhibiting pronounced differences at genus level between summer and winter seasons, with a significant delay in diatom settlement during winter. Electrochemical measurements indicated an active role of diatoms in increasing corrosion current during biofilm development. While the final diatom composition was similar irrespective of the season, the analyses of diatom assemblages over time differed, showing faster colonization when silicate and nitrate were available. This study lays the foundation for future research on the dominant season-specific genera of diatoms to unveil the microbial interactions that could contribute to corrosion and to evaluate their potential as bioindicators for alternative surveillance strategies. [ABSTRACT FROM AUTHOR]

The present study aims to explore the inhibitory action of lichen metabolites against important protein targets of marine fouling organisms using computational methods. Lichens with their unique ability to produce various secondary metabolites find versatile applications in Biotechnology and allied fields. The 3D structure of target proteins associated with fouling activity of marine organism were collected from the protein data bank (PDB) and the computational docking analysis was performed using the PyRx software with 40 lichen compounds that are collected from PubChem. The lichen compounds were docked against the following protein targets—mannose‐specific lectin CGL1 of Crassostrea gigas, Proximal thread matrix protein 1 PTMP 1 of Mytilus galloprovincialis, and G protein‐coupled receptor (GPCR) of Balanus amphitrite. As there was no experimentally determined structure available for GPCR of B. amphitrite, homology modeling was performed to predict the protein structure. The docking study showed effective binding of lichen compounds to various fouling targets with the binding energies in the range of −10.1 to −5 kcal/mol. Among the lichen compounds studied, roccanin showed the least binding energy for CGL1, PTMP1 and GPCR. The correlation assessments predict a positive relationship between binding energy, molecular weight and retention time. MD Simulation studies were performed using LARMD online tool and the RMSD and radius of gyration (Rg) values was recorded. This study proves that the compounds produced by lichens have high antifouling effect against marine foulers under in silico conditions. [ABSTRACT FROM AUTHOR]

Abandoned, lost, or otherwise discarded fishing gear (ALDFG) is a by‐product of many fisheries. ALDFG impacts extend beyond the targeted species and include by‐catch, habitat degradation, and increased plastic in the environment. In particular ALDFG such as lobster gear attracts a succession of fouling organisms, increasing species diversity and productivity.In Cape Cod Bay, Massachusetts, USA, a seasonal lobster gear closure occurs for the protection of North Atlantic right whales (Eubalaena glacialis), allowing for the removal of ALDFG. In this study, the percentage cover of fouling organisms on recovered gear was used to model the age of the recovered gear (of indeterminate age because of missing tags).Between 2017 and 2021, a total of 379 traps were photo documented, of which 223 were of known age (1–22 years) and 156 were of unknown age. The age of the unknown traps was modelled utilizing a random forest algorithm using traps with a known age as a training library.High correlations between modelled ages and known ages (R2 = 0.634, P < 0.001*) slightly underestimated the age of the traps by 1.2–1.8 years, but are sufficient for developing an age distribution. The majority (79%) of traps were recovered off Provincetown and averaged 10–11 years old. Approximately 50% of the traps recovered in Cape Cod Bay were deposited or lost between 2005 and 2010.Calculating the age of ALDFG aids in determining the loss rate of gear and in identifying high concentrations of untended gear that can be recycled or reused. This analysis allows practitioners to understand the scale of the problem, helps quantify the quantity of gear in the ocean, and helps identify the areas most affected. This information improves the effectiveness of removal efforts by focusing on discrete areas of recurring and recent gear loss. [ABSTRACT FROM AUTHOR]

Amphiphilic photopolymerized network films are prepared, based on a hexyl acrylate (HA) hydrophobic matrix containing varied amounts of urethane dimethacrylates bearing a hydrophilic poly(ethylene glycol) segment and terminated with hydrophobic, low surface energy groups, i.e., a short perfluorohexyl chain (for EF) or a fluorine‐free heptamethyltrisiloxane group (for ES). These films are extensively characterized in bulk and at the surface by thermal, mechanical, solvent and water uptake, contact angle, and X‐ray photoelectron spectroscopy measurements. On one hand, surface characterizations reveal that the amphiphilic chains of the additives enrich the topmost layer of the films, thus generating a water‐responsive surface. The reconstruction process is found to be faster for the perfluorinated additive EF and slower for the fluorine‐free ES ones. On the other hand, HA provides a hydrophobic matrix with low elastic modulus, dimensional stability, and adhesion to the substrates even after the absorption of water after prolonged immersion. A field immersion trial carried out in a touristic harbor in Leghorn points out that the films, although being ineffective in preventing organism settlement, are easily cleaned by a water jet after three months of immersion, showing a final residual coverage of panels as low as 15%. [ABSTRACT FROM AUTHOR]

This research aimed to reduce reliance on chemical antifouling agents; it was conducted at depths of 0.5 and 1.5 meters in the Eastern Harbor, at Alexandria, Mediterranean Sea. This study delves into the realm of environmentally sustainable antifouling solutions by exploring the efficacy of natural crude extracts from two Red Sea sponge species, Acanthella acuta (Extract A) and Carteriospongia sp. (Extract B). The results revealed a rich diversity of fouling organisms, encompassing six phyla, seven classes, eleven orders, twenty-two families, and thirty-three species. Noteworthy absences were noted at specific depths, indicating depth-dependent variations in fouling communities . The application of extract A at 0.5 meters depth demonstrated significant reductions in fouling biomass and shifts in dominant species. Treatment 3 stood out with the lowest biomass (9.69 ± 2.83 g/m² ) and the fewest species (only 2 species). At 1.5 meters depth, extract B exhibited consistent trends with treatment 6 displaying the lowest biomass (20.85 ± 23.35 g/m2 ) and also species diversity (only 2 species). Meanwhile, Extract B showcased compelling antifouling potential. At 0.5 meters depth, treatment 4 exhibited notable reductions in fouling biomass, dominated by Balanus amphitrite, Balanus eburneus, and Balanus sp. At 1.5 meters depth, treatment 6 emerged as the most effective, with the lowest biomass (249.3 ± 120.4 g/m² ) and a streamlined species composition. This study underscores the promise of natural crude extracts from the Red Sea sponges as potent alternatives for environmentally friendly antifouling strategies. The observed variations in fouling biomass and species composition offer critical insights for the development and application of these extracts in combating fouling organisms, presenting a significant stride toward sustainable marine ecosystem conservation. [ABSTRACT FROM AUTHOR]

The metallic pyrithiones are used as antifouling paints for marine vehicles against fouling organisms. However, they are dissolved in marine water and have negative impacts on marine non-target organisms. This study evaluated the adverse effects of sodium pyrithione (NaPT) on Mytilus galloprovincialis using total hemocyte counts (THCs), oxidative stress and antioxidant parameters, and histopathological observations. Mussels were exposed to 0.1 and 1 μg/L NaPT for 96 h. The THC values of the NaPT-exposed mussels significantly decreased (p < 0.05). Lipid peroxidation and advanced oxidative protein products of digestive gland and gill tissues were decreased but only the digestive gland tissues of 0.1 μg/L NaPT values were significantly decreased compared to control groups (p < 0.05). Histological alterations were observed in the gill and the digestive gland tissues revealing malformations and hyperplasia of gill lamella; degenerations and loss of tubules of digestive gland after exposure to NaPT for 96 h. As a result, biocidal sodium pyrithione has adverse effects on the mussels even in short-term exposures and low concentrations. [ABSTRACT FROM AUTHOR]

Marine biofouling, undesirable growth of organisms on submerged surfaces, poses significant challenges in various industries and marine applications. The development of environmentally safe antifouling coatings employing nano-MnO2/cellulose nanofiber (CNF) composite with bisphenol A epoxy diacrylate/glycidyl methacrylate (BED/GMA) irradiated by electron beam (T1) has been achieved in the current work. The physico-chemical characteristics of the fabricated coatings have been studied using Fourier transforms infrared spectroscopy, scanning electron microscope, water contact angle, and X-ray diffraction. The efficacy of T1 formulation and pure BED/GMA polymer (T2) in inhibiting biofouling formation was investigated in seawater of Alexandria Eastern Harbour by examining biofilm development morphologically and biochemically. In addition, regular analyses of seawater physicochemical parameters were conducted monthly throughout study. Results provide valuable information on coating performance as well as the complex interactions between coatings, biofilms, and environmental factors. The T1 formulation exhibited strong anti-fouling and anticorrosion properties over 2 months. However, after four months of immersion, all coated steel surfaces, including T1, T2, and T0, were heavily covered with macro-fouling, including tubeworms, barnacles, and algae. Biochemical analysis of extracellular polymeric substances (EPS) showed statistically significant variations in carbohydrates content between the coated surfaces. The T1 formulation showed decreased protein and carbohydrate content in EPS fractions after 14 days of immersion indicating less biofouling. Moreover, elemental analysis showed that carbon, oxygen, and iron were the predominant elements in the biofilm. Other elements such as sodium, silicon, chloride, and calcium were in lower concentrations. T2 and T0 surfaces revealed higher calcium levels and the appearance of sulphur peaks if compared with T1 surface. Diatoms and bacteria were detected on T1, T2, and T0 surfaces. The observed warming of seawater and nutrient-rich conditions were found to promote the growth of fouling organisms, emphasizing the importance of considering environmental factors in biofouling management strategies. [ABSTRACT FROM AUTHOR]

This is a phylogeographical study of Juxtacribrilina mutabilis, a recently described bryozoan from Japan with sightings in Sweden, Norway, and Maine (US), to test how fast and far it has expanded across Europe in recent years. J. mutabilis settles easily on ship hulls, making it a useful model organism for studying long-distance invasion pathways. The study was conducted using Autonomous Reef Monitoring Structures (ARMS) to monitor the entire European coastline and Svalbard for J. mutabilis using DNA metabarcoding. During the time between its first sighting in Europe 2008 and the last ARMS retrieval 2020, the data shows how J. mutabilis has gained a pan-European distribution, being genetically identified in 14 new distinct locations. Presence/absence of barcodes were confirmed by image-based identification in 74% of the samples. Fourteen haplotypes never reported before were discovered in a 264 bp region of the cytochrome oxidase I gene. Two haplotypes (HP1 and HP3) occurred frequently and geographically widely dispersed, indicating intercontinental connectivity. Two locations, Koster and Getxo showed particularly high genetic diversity with similar haplotype networks suggesting continuous gene flow across oceanographically unlinked regions. Given the recent description of J. mutabilis and the relatively few historical encounters, the genetic diversity described here suggests an unusually fast range expansion within the last two decades. Such global spreading events of fouling organisms may become more common in the future as a result of more frequent and interconnected ship traffic. [ABSTRACT FROM AUTHOR]

Marine habitats are being targeted for the extraction of offshore renewable energy (ORE) as part of the drive to decarbonise electricity generation. Unmanaged biofouling impacts ORE devices and infrastructure by elevating drag forces, increasing weight, and accelerating corrosion, leading to decreased performance and survivability, and extending costly periods of maintenance. ORE deployments in high tidal flow locations are providing opportunities to study the biofouling unique to these habitats. In this study, surveys of numerous devices and associated infrastructure deployed at the European Marine Energy Centre in Scotland identified high tidal flow fouling assemblages. Substrate orientation relative to tidal flow appears to affect the abundance of key fouling species, including the massive barnacle Chirona hameri. This species is shown to recruit to a wide range of artificial substrates, over a prolonged period from mid-spring to mid-summer, and in maximum current speeds from 0.4–4.0 m/s. For the first time, C. hameri is reported in near-surface depths, on uncoated components of a floating tidal device. The highly gregarious settlement behaviour and rapid growth exhibited by this species may have important implications for managing fouling in the ORE industry, especially in 'niche' areas. Anti-fouling strategies and maintenance scheduling applicable to ORE and other marine industries are discussed. [ABSTRACT FROM AUTHOR]

The adhesion of marine-fouling organisms to ships significantly increases the hull surface resistance and expedites hull material corrosion. This review delves into the marine biofouling mechanism on marine material surfaces, analyzing the fouling organism adhesion process on hull surfaces and common desorption methods. It highlights the crucial role played by surface energy in antifouling and drag reduction on hulls. The paper primarily concentrates on low-surface-energy antifouling coatings, such as organic silicon and organic fluorine, for ship hull antifouling and drag reduction. Furthermore, it explores the antifouling mechanisms of silicon-based and fluorine-based low-surface-energy antifouling coatings, elucidating their respective advantages and limitations in real-world applications. This review also investigates the antifouling effectiveness of bionic microstructures based on the self-cleaning abilities of natural organisms. It provides a thorough analysis of antifouling and drag reduction theories and preparation methods linked to marine organism surface microstructures, while also clarifying the relationship between microstructure surface antifouling and surface hydrophobicity. Furthermore, it reviews the impact of antibacterial agents, especially antibacterial peptides, on fouling organisms' adhesion to substrate surfaces and compares the differing effects of surface structure and substances on ship surface antifouling. The paper outlines the potential applications and future directions for low-surface-energy antifouling coating technology. [ABSTRACT FROM AUTHOR]

Carbon steels are widely used in ocean engineering due to their cost effectiveness, ease of manufacture, and excellent weldability. However, the attachment of macro-fouling organisms in seawater poses a serious threat to the integrity of carbon steel structures. In this experiment, carbon steel plates were immersed in the Dalian Sea area from January to October to investigate the effects of macro-fouling on corrosion propagation. The electrochemical measurement indicated that the propensity for the corrosion of Q235B is ranked as ascidians > mussels > barnacles. The characterization results indicated that various marine organisms significantly influenced the corrosion behavior of Q235B carbon steel immersed in natural seawater. The colonization of barnacles inhibited corrosion at the barnacle central area, and the presence of barnacle covering caused crevice corrosion at the edges of the barnacle due to oxygen concentration cells. The presence of ascidians resulted in general corrosion due to the locally high conductivity and ion diffusion rate. A relatively compact rust layer, which exhibited localized defects, was observed beneath the mussels. Seawater had the ability to penetrate the rust layer through these defects, leading to the formation of pitting corrosion on the metal substrate. [ABSTRACT FROM AUTHOR]

The aim of this study was to develop a method for assessing the growth of photoautotrophs on plaster coatings, which will be used to reliably assess the resistance of these materials to photoautotrophic growth in the simulation of long-term exposure. In the course of the study, mineral and silicone plaster substrates were inoculated with a mixture of Stichococcus bacillaris, Nostoc commune, Pseudochlorella signiensis, and Coenochloris signiensis, and incubated for 28 days in model conditions. At 14 and 28 days after inoculation, the degree of photoautotrophic growth was determined using hemocytometer cell counting, a HY-LiTE 2 ATP measuring system, chlorophyll a concentration quantification, CIE L*a*b spectrophotometric color change evaluation, and visual assessment. The acquired results allowed us to select visual assessment and spectrophotometric color change evaluation as quick-to-perform and reliable techniques for further laboratory studies. The impact of minor changes introduced in the inoculation and incubation procedures on the rate of biofilm formation and severity of microbial fouling was studied. Differences in inoculation and incubation procedures strongly affected the results of the performed tests. Both methods have shown high potential and should be further expanded upon in environmental studies. [ABSTRACT FROM AUTHOR]

This study aimed to study the settlement of fouling organisms in the Eastern Harbor of Alexandria during the period from 2019 to 2020. Seasonal samples of marine fouling invertebrate species had been collected using white roughened wood test panels. Some environmental parameters (temperature, transparency, salinity, pH, and dissolved oxygen) were studied. The fouling invertebrate species and taxa were identified and classified. Statistical analysis was conducted using primer and paste software. The results of this study showed that some environmental parameters such as dissolved oxygen and water temperature of marine water in Eastern Harbor, Alexandria can significantly affect the settlement of fouling organisms. The results showed also that the fouling was composed of 37 invertebrate species, belonging to 23 families, within 12 orders, 7 classes, and 6 phyla. The highest diversity phyla were Crustacea (20 species from 11 families), followed by Bryozoa (7 species from 7 families) and Annelida (6 species from 2 families). The biomass of fouling invertebrate families and their species varied in different depths. The most heavy families were Serpulidae and Balanidae. At 0.5 m depth, Hydroides elegans had the mostly heavy biomass (2720.2±1716.3 g/m2); followed by Balanus amphitrite (889.3±687.4 g/m2). At 1.5 m depth, also Hydroides elegans had the heavy biomass (2264.6±2506.7 g/m2); followed byBalanus perforates (1691.3±3198.3 g/m2). Seasonal variation in fouling invertebrate biomass showed that Hydroides eleganes represented the heaviest recorded biomass during spring, summer and autumn, while Balanus amphitrite was the heaviest biomass observed during winter. [ABSTRACT FROM AUTHOR]

Non-indigenous species tend to colonize aquaculture installations, especially when they are near international ports. In addition to the local environmental hazard that colonizing non-indigenous species pose, they can also take advantage of local transport opportunities to spread elsewhere. In this study, we examined the risk of the spread of eight invasive fouling species that are found in mussel farms in southern Brazil. We used ensemble niche models based on worldwide occurrences of these species, and environmental variables (ocean temperature and salinity) to predict suitable areas for each species with three algorithms (Maxent, Random Forest, and Support Vector Machine). As a proxy for propagule pressure, we used the tonnage transported by container ships from Santa Catarina (the main mariculture region) that travel to other Brazilian ports. We found that ports in the tropical states of Pernambuco, Ceará, and Bahia received the largest tonnage, although far from Santa Catarina and in a different ecoregion. The ascidians Aplidium accarense and Didemnum perlucidum are known from Bahia, with a high risk of invasion in the other states. The bryozoan Watersipora subtorquata also has a high risk of establishment in Pernambuco, while the ascidian Botrylloides giganteus has a medium risk in Bahia. Paraná, a state in the same ecoregion as Santa Catarina is likely to be invaded by all species. A second state in this region, Rio Grande do Sul, is vulnerable to A. accarense, the barnacle Megabalanus coccopoma, and the mussel Mytilus galloprovincialis. Climate change is changing species latitudinal distributions and most species will gain rather than lose area in near future (by 2050). As an ideal habitat for fouling organisms and invasive species, aquaculture farms can increase propagule pressure and thus the probability that species will expand their distributions, especially if they are close to ports. Therefore, an integrated approach of the risks of both aquaculture and nautical transport equipment present in a region is necessary to better inform decision-making procedures aiming at the expansion or establishment of new aquaculture farms. The risk maps provided will allow authorities and regional stakeholders to prioritize areas of concern for mitigating the present and future spread of fouling species. [ABSTRACT FROM AUTHOR]

Biofouling is a significant means for introducing non-indigenous marine species internationally, which can alter habitats and disturb marine ecosystems. This study estimated the flux of ships' wetted surface area (WSA) to Korea in 2020 to assess the risks of biological invasion via biofouling on ships' hulls. The annual total WSA flux entering Korea was estimated to be 418.26 km2, with short-stay vessels (<3 weeks) contributing to 99.7% of the total WSA flux. Busan and Ulsan ports were identified as the main sources of high-risk flux, with container ships being a major vector in Busan and tankers in Ulsan. Gwangyang port had the third-highest total WSA flux, with nearly half of the flux driven from coastwise voyages, making it particularly vulnerable to the spread of hull fouling organisms. These findings could help enhance the management and inspection of hull fouling organisms in Korea. [ABSTRACT FROM AUTHOR]

Implantable electrochemical sensors that enable the real-time detection of significant biomarkers offer huge potential for the enhancement and personalisation of therapies; however, biofouling is a key challenge encountered by any implantable system. This is particularly an issue immediately after implantation, when the foreign body response and associated biofouling processes are at their most active in passivating a foreign object. Here, we present the development of a sensor protection and activation strategy against biofouling, based on coatings consisting of a pH-triggered, dissolvable polymer, that covered a functionalised electrode surface. We demonstrate that reproducible delayed sensor activation can be achieved, and that the length of this delay can be controlled by the optimisation of coating thickness, homogeneity and density through tuning of the coating method and temperature. Comparative evaluation of the polymer-coated and uncoated probe-modified electrodes in biological media revealed significant improvements in their anti-biofouling characteristics, demonstrating that this offers a promising approach to the design of enhanced sensing devices. [ABSTRACT FROM AUTHOR]

A specimen of bull ray Aetomylaeus bovinus was captured dead by a diver around a tuna sea cage farm. It was female, measured 2310 mm in total length (TL) and 1460 mm in disc width (DW) with body weight estimated as about 20 kg. This case was reported from a tuna farm for the first time. The bull ray entered the sea cage about three months ago, but no attack occurred to the tuna in the cage. It was grazing on fouling organisms that attached to the nets. However, the cage nets were replaced with clean ones four days ago before the capture, and the bull ray did not find enough fouling organisms or uneaten fish feed and was starved to death. [ABSTRACT FROM AUTHOR]

Fouling organisms reduce a ship's fuel efficiency and disturb the ecosystem. Therefore, the International Maritime Organization (IMO) and many nations have enacted laws that mandate periodic hull cleaning for removing fouling organisms. However, cleaning niche areas of the ship hull is extremely difficult. Due to their complex shape, applying antifouling paint and cleaning with hull cleaning robots is difficult, but about 80% of fouling organisms are concentrated in the niche areas. To resolve this issue, this research proposes the use of an autonomous cleaning robot with a hydraulic polyarticular robot arm to clean niche areas of the ship hull. This robot can approach niche areas of the ship hull with complex shapes using its polyarticular arm. It was designed to be able to scan the cleaning area, establish a cleaning plan, and clean accordingly. This robot autonomously cleaned a propeller blade, which is a typical niche area of the ship hull, to verify the applicability of this system. The experiment results show that approximately 80% of the biofouling was removed from the hull crevices and 81% of the cleaned biofouling was recovered. [ABSTRACT FROM AUTHOR]

The performance of fouling control coatings (FCC) is evaluated based on static exposure on test sites worldwide. There are different standards concerning the evaluation of the performance of the FCC. However, to the knowledge of the authors, there is not a standardized reporting guideline for how to evaluate the test site in which the FCC is exposed. Several factors such as water conditions, seasonal biofouling, and accessibility of sunlight can vary dependent on placement within or between test sites. This in turn makes it difficult to compare the performance of FCC exposed at different locations within a or at another test site. In this study, an analysis of the CoaST Maritime Test Centre (CMTC) has been performed to investigate how geographical orientation and changes in depth influence the biofouling propensity on coated panels. The investigation showed no statistical significance in the biofouling propensity between panels exposed to different geographical orientations at the CMTC. Similarly, no statistical significance was found between panels placed at different depths at the CMTC. If similar reporting was performed at other test sites, a better basis for comparison of FCC worldwide would be obtained, and this could be achieved with a standardized reporting guideline. [ABSTRACT FROM AUTHOR]

With increasing numbers of antimicrobial‐resistant (AMR) bacteria strains, it becomes essential that new and effective routes to minimizing bacterial infection rates are produced. Superhydrophobic materials show to be effective in reducing the attachment of bacteria due to their unique wetting properties which can minimize the points at which bacteria can initially adhere. Here, the impact of surface design on the anti‐biofouling capabilities of superhydrophobic pillared arrays prepared via photolithography is investigated. By systematically varying pillar spacing, insight is gained into the complex nature of superhydrophobic fouling as well as allowing for optimization of the antifouling performance. The optimal material within is achieved at a pillar spacing of 87.5 µm, which shows over a 3‐log (and gt; 99.9%) reduction in bacterial attachment. [ABSTRACT FROM AUTHOR]

A new species belonging to the genus Parathalestris Brady & Robertson, 1873 was identified and described here based on samples recently collected from a survey on fouling organisms at the Zhonggang wharf in Qingdao, China. The new species differs from its congeners in the following characteristics: caudal rami 2.0 times longer than wide, with bulbous setae II and setae III of caudal ramus issuing terminally and laterodistally, respectively; exopod of antenna two-segmented, with two setae on first segment and four setae on second one;maxilla with two bipinnate setae on proximal endite, and three spinulose setae on middle and distal endites; basis of maxilliped with concave inner edge; P1 exopod and endopod approximately same length, enp-1 about 6.7 times as long as greatest width, with inner seta reaching proximal 2/3 of segment; baseoendopod and exopod of female P5 with transversal rows of spinules on its surface, exopod bearing six marginal setae; male P1 carrying an inner curved spine on basis; exopod of male P5 bearing six elements. The DNA barcode (COI) sequence of the new species was obtained and submitted to GenBank. This is the first report of Parathalestris from the China Seas. [ABSTRACT FROM AUTHOR]

Microbial biofilm development on the membrane surface of bioreactors results in membrane flux decline (biofouling). Biofouling is one of the most severe problems limiting the use of these bioreactors. For detailed understanding of the biofouling, microbial community and dissolved organic matter analyses have been performed in recent decades. Although most previous studies have focused on mature biofilms at the end point of biofouling, understanding of the early stages is crucial to mitigate biofilm formation. Thus, recent studies have focused on the impact of early-stage biofilm development and indicated a clear difference in microbial communities between early-stage and mature biofilms. In addition, certain bacteria play a significant role in early-stage biofilms. The present mini-review systematically summarizes the foulants present during early-stage fouling, provides novel perspectives on fouling mechanisms, and discusses the neglected effect of planktonic bacteria. [ABSTRACT FROM AUTHOR]

Organic compounds, including antimicrobial agents azithromycin and hydrous allicin extracts, were sequestered in a silicate sol–gel matrix to function as a biofouling-resistant window for oceanographic instrumentation. The windows fabricated in this manner resisted the formation of microbial biofilms (the precursor to settlement of larger macro-fouling organisms) for up to a week and maintained low levels of fouling for 3 weeks, whereas bare glass substrates form biofilms within hours of seawater submersion. The technique shows promise for the construction of additional translucent solids and coatings using other environmentally friendly biocides. [ABSTRACT FROM AUTHOR]

Many marine invertebrates have planktonic larval and benthic juvenile/adult stages. When the planktonic larvae are fully developed, they must find a favorable site to settle and metamorphose into benthic juveniles. This transition from a planktonic to a benthic mode of life is a complex behavioral process involving substrate searching and exploration. Although the mechanosensitive receptor in the tactile sensor has been implicated in sensing and responding to surfaces of the substrates, few have been unambiguously identified. Recently, we identified that the mechanosensitive transient receptor potential melastatin-subfamily member 7 (TRPM7) channel, highly expressed in the larval foot of the mussel Mytilospsis sallei, was involved in substrate exploration for settlement. Here, we show that the TRPM7-mediated Ca2+ signal was involved in triggering the larval settlement of M. sallei through the calmodulin-dependent protein kinase kinase β/AMP-activated protein kinase/silk gland factor 1 (CaMKKβ-AMPK-SGF1) pathway. It was found that M. sallei larvae preferred the stiff surfaces for settlement, on which TRPM7, CaMKKβ, AMPK, and SGF1 were highly expressed. These findings will help us to better understand the molecular mechanisms of larval settlement in marine invertebrates, and will provide insights into the potential targets for developing environmentally friendly antifouling coatings for fouling organisms. [ABSTRACT FROM AUTHOR]

Ship hull fouling is recognized as an important vector for the introduction of nonindigenous species (NIS), which has been studied globally but no empirical works exist in the Southeast Pacific. The present study examined fouling organisms on the hulls of three ships in one international Chilean port, and compared them with those on settling plates and natural substrates. Also, genetic analyses were perfomed on the most common NIS recorded in order to explore number and potential origin of the genetic linages found. The highest number of total taxa and NIS were found on ship hulls, with three species identified as NIS in ship samplings. Settling plates displayed the largest number of taxa, with a large abundance of the invasive tunicate Ciona robusta, which also showed high mitochondrial genetic diversity. This study showed that Chilean coasts are subjected to both NIS colonization and propagule pressure through ship hulls. Biosecurity measures should urgently be taken on ship hulls along these coasts. [ABSTRACT FROM AUTHOR]

In the last few years, the endemic Mediterranean bivalve Pinna nobilis has been exposed to dramatic mortality in its entire area, which could lead to the extinction of the species. Throughout the Mediterranean, a lot of effort is being put into finding ways of preserving it. One of the methods used to monitor recruitment and juveniles' survival is the installation of collectors for bivalve larvae. We installed collectors at two locations: in Brijuni National Park (North Adriatic) and Luka Cove (central Adriatic). Our aim was to compare the fouling community on the collectors in two consecutive years (2019 and 2020), especially because the installation of collectors in 2020 coincided with mass mortality events of P. nobilis in the area. The number and size of juvenile P. nobilis and the qualitative and quantitative composition of the fouling communities were determined. The results show a reduction in the number and size of juvenile P. nobilis and an explosion of the invasive bivalve Anadara transversa population on collectors in the second year. In Luka Cove, another invasive species—the ascidian Styela plicata—also seriously affected other organisms on the collectors to the point of preventing analysis of the fouling community. [ABSTRACT FROM AUTHOR]

Marine resources such as marine invertebrates and mangrove plants favor the production of secondary metabolites that exhibit antifouling properties. These natural-derived compounds are considered environmentally friendly compared to synthetic compounds with similar activity and technological applications. The current study was conducted to determine the antifouling properties of Diadema setosum (DS) and Sonneratia lanceolata (SL) crude extracts and their incorporated paints, in addition to the identification of the metabolites involved. Both crude extracts were tested against Pseudomonas aeruginosa via a crystal violet assay, while the incorporated paints with 5% (SL5% and DS5%) and 10% (SL10% and DS10%) weight per volume (w/v) were tested in an aquarium and submerged in the seawater at Kemaman and Pulau Redang (Malaysia) for field testing. The identification of the bioactive compounds from the crude extracts was carried out using Liquid Chromatography-Mass Spectrometry (LC-MS). The results of the crystal violet assay showed that both of the crude extracts reduced the biofilm formed by Pseudomonas aeruginosa. The marine bacteria growths contained in natural seawater were inhibited the most by SL5%, followed by DS5%, DS10%, and SL10% in the aquarium testing. Based on the photographic observation, all of the paints incorporated with the crude extracts successfully reduced the settlement of fouling organisms compared to the blank paint, as lesser macroalgae were found growing on the SL5%, DS5%, and DS10%. The LC-MS results showed 3-Methyloxiranyl phosphonic acid; (2RS,3SR)-form from the SL crude extract, while the 8-Decene-1,3,5-triol, 3-Hydroxyundecanoic acid, and 1-O-(6-Deoxy-6-sulfoglucopyranosyl)glycerol; α-D-form, 3-Hexadecanoyl from the DS crude extract were involved in the antifouling properties. In conclusion, both crude extracts have the potential to be developed as antifouling agents. [ABSTRACT FROM AUTHOR]