Lamprey reddening syndrome (LRS) is an emerging disease affecting pouched lamprey (Geotria australis; kanakana/piharau), a culturally and ecologically significant species in Aotearoa, New Zealand. Characterized by skin hemorrhaging and elevated mortality, the etiology of LRS has remained unresolved despite previous investigations. We used a metatranscriptomic approach to characterize viral communities in 28 lamprey from New Zealand and Tasmania, Australia, comparing diseased and presumably healthy individuals. This analysis revealed eight fish-infecting RNA viruses, seven of which were novel, including two highly divergent coronaviruses. One of these coronaviruses possessed a bisegmented genome structure, and three lamprey were co-infected with both coronaviruses. While these coronaviruses were detected in both healthy and diseased individuals, lamprey with reddening exhibited markedly higher viral abundance, driven by elevated RNA transcripts of both viruses. This pattern suggests that increased coronavirus replication in diseased individuals may be influenced by host stress to environmental factors, or co-infection with other pathogens, rather than acting as a sole causative agent of disease. Beyond identifying candidate viral associations, this study expands the known virosphere of an ancient vertebrate lineage and demonstrates the utility of genomics-informed diagnostics for investigating disease in threatened wildlife. IMPORTANCE:Lamprey are among the world's oldest living vertebrates and hold deep cultural significance for Māori as taonga species. An emerging disease causing skin reddening and death has raised concerns for their long-term conservation, but its cause has remained unknown. By applying genomic sequencing, we discovered a remarkable diversity of previously unknown viruses, including two highly unusual coronaviruses, in New Zealand and Australian lamprey. Rather than identifying a single disease-causing virus, our results suggest that disease is more likely associated with increased viral replication in stressed animals or with multiple infections acting together. These findings provide an important step toward understanding the health of this threatened species while also revealing unexpected viral diversity in an ancient vertebrate lineage. More broadly, the study demonstrates how genomics-informed diagnostics can help investigate unexplained disease outbreaks in wildlife and guide conservation management.

Mimics of natural cationic antimicrobial peptides have demonstrated high antimicrobial activity, and their essential pharmacophore can be effectively incorporated into the cyclic 2,5-diketopiperazine scaffold. Control over bioactivity and selectivity can be achieved by altering the balance between charge and hydrophobicity and by employing a range of small electron-withdrawing and electron-donating substituents; compounds with good antibacterial potency (low μM) could be prepared. The lead compounds prepared in this study had comparable antimicrobial potency to the antibiotic positive controls and the antimicrobial peptide LTX-109, against both Gram-positive and Gram-negative bacteria and multidrug-resistant strains. The off-target toxicity against human red blood cells and VERO cells revealed a good cellular selectivity. Nontoxic and highly potent small compounds were thus prepared, which were comparable or superior to several short antimicrobial peptide mimics under clinical development. A clear link to N-substituent hydrophobicity was revealed, and hydrophobicity thresholds for both cellular selectivity and antimicrobial activity were identified.

Biofouling within vessel sea chests and internal seawater systems (ISS) presents a range of operational and biosecurity issues. Marine Growth Prevention Systems (MGPS) are designed to prevent biofouling accumulation in these areas, however independent data regarding their efficacy is scarce. Sacrificial copper anode MGPS, which operate by releasing reactive copper ions, have the dominant market share. In this study, we tested copper dosages generated using cupric chloride to mimic cupric ion (Cu2+) generation by copper anode-based MGPS. We assessed the effect of copper dosages, including those recommended by MGPS manufacturers, on mortality of larval biofouling species (Ciona savignyi and Crassostrea gigas) and mature biofouling communities under various environmental conditions. Minimum inhibitory concentrations (MICs) were 2-3 orders of magnitude higher than MGPS manufacturer-reported dosages for both larval and mature biofouling. Efficacy varied with exposure regime, organic matter load, biofouling species, and organism development stage. Based on our results, short-term copper MGPS dosing according to current manufacturer recommendations appears insufficient to manage biosecurity risks within sea chests and ISS.

Parasites can provide valuable insights into the ecology and health of their hosts and the state of the surrounding ecosystem. In this study, we describe the helminth parasite communities infecting penguin species in Otago, New Zealand (little blue penguin, Fiordland crested penguin, Snares crested penguin, erect crested penguin and yellow-eyed penguin). We investigate differences in parasite communities among penguin species, and changes over time for little blue penguins. In total, 19 parasite species representing 8 families (Desmidocercidae, Anisakidae, Acuariidae, Capillariidae, Tetrabothriidae, Heterophyidae, Renicolidae and Polymorphidae) were recorded from 121 penguin individuals. Parasite assemblages differed among penguin species, likely reflective of their differences in diet and feeding strategies. We also observed significant changes in the composition of parasite communities of little blue penguins using samples from a 30-year timespan (1993–2023). There was an overall increase in parasite diversity over time, including some species of potential disease concern, which could reflect a shift in prey availability of fish in the area. Our findings contribute to the understanding of penguin ecology and emphasise the use of parasites as indicators of ecological change.

Anthropogenic vectors (transfer mechanisms) can facilitate the introduction and spread of aquatic disease in marine farming regions. Preventing or interrupting pathogen transfers associated with movements of these vectors is key to ensuring productivity and profitability of aquaculture operations. However, practical methods to identify and manage vector risks are lacking. We developed a risk analysis framework to identify disease risks and management gaps associated with anthropogenic vector movements in New Zealand’s main aquaculture sectors - Chinook salmon ( Oncorhynchus tshawytscha ), green-lipped mussels ( Perna canaliculus ), and Pacific oysters ( Crassostrea gigas ). Vectors within each sector were identified and assigned categorical risk scores for (i) movement characteristics (size, frequency, likelihood of return to sea), (ii) biological association with pathogens (entrainment potential, contribution to previous aquaculture disease outbreaks) and (iii) available best practice biosecurity methods and tools, to inform unmitigated and mitigated risk rankings. Thirty-one vectors were identified to operate within the national network and association with livestock was found to be a primary driver of vector risk rankings. Movements of live growing stock and culture substrates (e.g., mussel ropes) in shellfish farming had high-risk vector profiles that are logistically challenging to address, while vessel vectors were identified as the salmon farming sector’s priority. The framework and rankings can be used to inform both research and management priorities in aquaculture and other primary production systems, including risk validation, vector roles in disease epidemiology, compliance with permit conditions, policy development, and treatment options.

The unwanted accumulation of marine micro- and macroorganisms such as algae and barnacles on submerged man-made structures and vessel hulls is a major challenge for any marine operation. Known as biofouling, this problem leads to reduced hydrodynamic efficiency, significantly increased fuel usage, microbially induced corrosion, and, if not managed appropriately, eventual loss of both performance and structural integrity. Ship hull biofouling in the international maritime transport network conservatively accounts for 0.6% of global carbon emissions, highlighting the global scale and the importance of this problem. Improved antifouling strategies to limit surface colonization are paramount for essential activities such as shipping, aquaculture, desalination, and the marine renewable energy sector, representing both a multibillion dollar cost and a substantial practical challenge. From an ecological perspective, biofouling is a primary contributor to the global spread of invasive marine species, which has extensive implications for the marine environment.Historically, heavy metal-based toxic biocides have been used to control biofouling. However, their unwanted collateral ecological damage on nontarget species and bioaccumulation has led to recent global bans. With expanding human activities within aquaculture and offshore energy, it is both urgent and apparent that environmentally friendly surface protection remains key for maintaining the function of both moving and stationary marine structures. Biofouling communities are typically a highly complex network of both micro- and macroorganisms, representing a broad section of life from bacteria to macrophytes and animals. Given this diversity, it is unrealistic to expect that a single antifouling "silver bullet" will prevent colonization with the exception of generally toxic biocides. For that reason, modern and future antifouling solutions are anticipated to rely on novel coating technologies and "combination therapies" where mixtures of narrow-spectrum bioactive components are used to provide coverage across fouling species. In contrast to the existing cohort of outdated, toxic antifouling strategies, such as copper- and tributyltin-releasing paints, modern drug discovery techniques are increasingly being employed for the rational design of effective yet safe alternatives. The challenge for a medicinal chemistry approach is to effectively account for the large taxonomic diversity among fouling organisms combined with a lack of well-defined conserved molecular targets within most taxa.The current Account summarizes our work employing the tools of modern medicinal chemistry to discover, modify, and develop optimized and scalable antifouling solutions based on naturally occurring antifouling and repelling compounds from both marine and terrestrial sources. Inspiration for rational design comes from targeted studies on allelopathic natural products, natural repelling peptides, and secondary metabolites from sessile marine organisms with clean exteriors, which has yielded several efficient and promising antifouling leads.

Biofouling of ships' internal seawater systems (ISS) can cause significant operational issues and is a potential transfer mechanism for marine nonindigenous species. This study used an engine room simulator and economic evaluation to quantify impacts on commercial ship performance of biofouling occlusion within various ISS nodes (sea chest, strainer, and heat exchangers). A characteristic hockey-stick relationship between occlusion and impact emerged, whereby engine room systems could tolerate up to 55% occlusion of a single node without operational impact, followed by rapid performance deterioration. The relative magnitude of impacts varied by ISS node and in response to changes in ambient seawater temperatures. System tolerance was much lower when simultaneous occlusion of multiple nodes was assessed. In economic terms, consequences included required freight rate increases of 1-26% prior to forced (automatic) slowdown of the ship and up to 82% increases if slowdown conditions were required.

Resolving the cause of disease (= aetiology) in aquatic organisms is a challenging but essential goal, heightened by increasing disease prevalence in a changing climate and an interconnected world of anthropogenic pathogen spread. Emerging diseases play important roles in evolutionary ecology, wildlife conservation, the seafood industry, recreation, cultural practices, and human health. As we emerge from a global pandemic of zoonotic origin, we must focus on timely diagnosis to confirm aetiology and enable response to diseases in aquatic ecosystems. Those systems' resilience, and our own sustainable use of seafood, depend on it. Synchronising traditional and recent advances in microbiology that span ecological, veterinary, and medical fields will enable definitive assignment of risk factors and causal agents for better biosecurity management and healthier aquatic ecosystems.

There is a lack of cost-effective, environmentally-friendly tools available to manage marine biofouling accumulation on static artificial structures such as drilling rigs, wind turbines, marine farms, and port and marina infrastructure. For there to be uptake and refinement of tools, emerging technologies need to be tested and proven at an operational scale. This study aimed to see whether biofouling accumulation could be suppressed on marine infrastructure under real-world conditions through the delivery of continuous bubble streams. Submerged surfaces of a floating marina pontoon were cleaned in-situ by divers, and the subsequent colonisation by biofouling organisms was monitored on treated (bubbles applied) and untreated sections. Continuous bubble streams proved highly effective (>95%) in controlling macrofouling accumulation on the underside surface of the marina pontoon for the first 2 months after deployment, but efficacy dropped off rapidly once bubble stream delivery was partially obscured due to biofouling accumulation on the diffuser itself. Although extensive macrofouling cover by mussels, bryozoans and hydroids was observed on treated surfaces by 4 months (27.5%, SE = 4.8%), biofouling % cover and diversity was significantly higher on untreated surfaces (79.6%, SE = 2.9%). While this study demonstrates that continuous bubble streams greatly restrict biofouling accumulation over short-to-medium timescales, improved system design, especially the incorporation of diffusers resistant to fouling, is needed for the approach to be considered a viable long-term option for biofouling management on static artificial structures.

Abstract Biofouling is a major global environmental and economic challenge wherein organisms settle on solid surfaces submerged in natural waters. This leads to the spread of invasive marine species around the globe, accelerates surface deterioration through microbially‐induced corrosion, and inflates maritime vessel fuel consumption which leads to greater greenhouse gas emissions. In this study, pulsed plasma poly(styrene) nanocoatings impregnated with eco‐friendly liquids are produced that yield slippery surfaces through aromatic–aliphatic intermolecular interactions (water droplet contact angle hysteresis and sliding angle values ≈1–2°). The antibiofouling performance of these slippery surfaces is demonstrated using laboratory‐based marine bioassays and real‐world field trials in freshwater (pond water) and seawater (ocean) environments. Low‐cost and substrate‐independent pulsed plasmachemical deposition combined with eco‐friendly liquid impregnation provides a sustainable approach to tackling environmental biofouling.

This study reports the development of a class of eco-friendly antifouling biocides based on a cyclic dipeptide scaffold, 2,5-diketopiperazine (2,5-DKP). The lead compound cyclo(N-Bip-l-Arg-N-Bip-l-Arg) (1) was synthesized in gram amounts and used to assess the compatibility with an ablation/hydration coating, efficacy against biofouling, and biodegradation. Leaching of 1 from the coating into seawater was assessed via a rotating drum method, revealing relatively stable and predictable leaching rates under dynamic shear stress conditions (36.1 ± 19.7 to 25.2 ± 9.1 ng-1 cm-2 day-1) but low or no leaching under static conditions. The coatings were further analyzed using time-of-flight secondary ion mass spectrometry (ToF-SIMS), with 1 seen to localize at the surface of the coating in a surfactant-like fashion. When coatings were deployed in the ocean, detectable reductions in biofouling development were measured for up to 11 weeks. After this time, biofouling overwhelmed the performance of the coating, consistent with leaching kinetics. Biodegradation of 1 in seawater was assessed using theoretical oxygen demand and analytical quantification. Masking effects were observed at higher concentrations of 1 due to antimicrobial properties, but half-lives were calculated ranging from 13.4 to 16.2 days. The results can rationally inform future development toward commercial antifouling products.

Feathers of seabirds and waterfowl (for example the mallard duck (Anas platyrhynchos)) consist of hierarchical fibrillar structures encapsulated with hydrophobic preen oil. These characteristics afford waterproofing through the entrapment of air pockets, enabling swimming and diving for such bird species. This liquid repellency mechanism for bird feathers is mimicked by surface hydrophobisation of fibrous nonwoven polypropylene textiles to create large volumes of trapped air at the solid-liquid interface (plastron). Higher static water contact angle values correlate to a greater resistance towards water ingress (akin to the behaviour of mallard feathers). In order to extend the trapped gas layer lifetimes, the transportation of air from the water surface to a submerged air bubble by the diving bell spider (Argyroneta aquatica) for respiration is mimicked via short duration (< 1 s) solar-powered air bubble bursts once every 2 h. This combination of ornithological and arachnological inspired approaches yields stable trapped gas layers at the solid-liquid interface which are shown to inhibit biofouling in real-world outdoor wet environments.

Two new ircinianin-type sesterterpenoids, ircinianin lactone B and ircinianin lactone C (7 and 8), together with five known entities from the ircinianin compound family (1, 3–6) were isolated from the marine sponge Ircinia wistarii. Ircinianin lactones B and C (7 and 8) represent new ircinianin terpenoids with a modified oxidation pattern. Despite their labile nature, the structures could be established using a combination of spectroscopic data, including HRESIMS and 1D/2D NMR techniques, as well as computational chemistry and quantum-mechanical calculations. In a broad screening approach for biological activity, the class-defining compound ircinianin (1) showed moderate antiprotozoal activity against Plasmodium falciparum (IC50 25.4 μM) and Leishmania donovani (IC50 16.6 μM).

Pests of bivalve aquaculture are a challenging problem that can reduce productivity, profitability and sustainability. A range of pest management approaches have been developed for bivalve aquaculture, but a general absence of guiding frameworks has limited the scale and permanency of implementation. Applying principles of 'integrated pest management' (IPM) could change this paradigm to improve economic and environmental outcomes. We reviewed existing research and tools for pest management in bivalve aquaculture, with studies grouped under five pillars of IPM: pest ecology (25 studies), bioeconomic cost-benefits (4 studies), continual monitoring (17 studies), proactive prevention (32 studies) and reactive control (65 studies). This body of knowledge, along with insights from terrestrial agriculture, provide a strong foundation for developing and implementing IPM in bivalve aquaculture. For example, IPM principles have been applied by a regional collective of oyster farmers in the US Pacific Northwest to optimize pesticide application and search for other options to control problematic burrowing shrimps. However, IPM has not yet been broadly applied in aquaculture, and data gaps and barriers to implementation need to be addressed. Priorities include establishing meaningful pest-crop bioeconomic relationships for various bivalve farming systems and improving the efficacy and operational scale of treatment approaches. An IPM framework also could guide potential step-change improvements through directing selective breeding for resistance to pests, development of bespoke chemical control agents, applying emerging technologies for remote surveillance and farm management, and regional alignment of management interventions. (c) 2022 Society of Chemical Industry.

Marine plastic debris (MPD) are a global threat to marine ecosystems. Among countless ecosystem impacts, MPD can serve as a vector for marine 'hitchhikers' by facilitating transport and subsequent spread of unwanted pests and pathogens. The transport and spread of these non-indigenous species (NIS) can have substantial impacts on native biodiversity, ecosystem services/functions and hence, important economic consequences. Over the past decade, increasing research interest has been directed towards the characterization of biological communities colonizing plastic debris, the so called Plastisphere. Despite remarkable advances in this field, little is known regarding the recruitment patterns of NIS larvae and propagules on MPD, and the factors influencing these patterns. To address this knowledge gap, we used custom-made bioassay chambers and ran four consecutive bioassays to compare the settlement patterns of four distinct model biofouling organisms' larvae, including the three notorious invaders Crassostrea gigas, Ciona savignyi and Mytilus galloprovincialis, along with one sessile macro-invertebrate Spirobranchus cariniferus, on three different types of polymers, namely Low-Linear Density Polyethylene (LLDPE), Polylactic Acid (PLA), Nylon-6, and a glass control. Control bioassay chambers were included to investigate the microbial community composition colonizing the different substrates using 16S rRNA metabarcoding. We observed species-specific settlement patterns, with larvae aggregating on different locations on the substrates. Furthermore, our results revealed that C. savignyi and S. cariniferus generally favoured Nylon and PLA, whereas no specific preferences were observed for C. gigas and M. galloprovincialis. We did not detect significant differences in bacterial community composition between the tested substrates. Taken together, our results highlight the complexity of interactions between NIS larvae and plastic polymers. We conclude that several factors and their potential interactions influenced the results of this investigation, including: (i) species-specific larval biological traits and ecology; (ii) physical and chemical composition of the substrates; and (iii) biological cues emitted by bacterial biofilm and the level of chemosensitivity of the different NIS larvae. To mitigate the biosecurity risks associated with drifting plastic debris, additional research effort is critical to effectively decipher the mechanisms involved in the recruitment of NIS on MPD.

Biofouling accumulation is not proactively managed on most marine static artificial structures (SAS) due to the lack of effective options presently available. We describe a series of laboratory and field trials that examine the efficacy of continuous bubble streams in maintaining SAS free of macroscopic biofouling and demonstrate that this treatment approach is effective on surface types commonly used in the marine environment. At least two mechanisms were shown to be at play: the disruption of settlement created by the bubble stream, and the scouring of recently settled larvae through shear stress. Field trials conducted over a one-year period identified fouling on diffusers as a major issue to long-term treatment applications. Field measurements suggest that noise associated with surface mounted air blowers and sub-surface diffusers will be highly localised and of low environmental risk. Future studies should aim to develop and test systems at an operational scale.

The number, extent, diversity, and global reach of submerged static artificial structures (SSAS) in the marine environment is increasing. These structures are prone to the accumulation of biofouling that can result in unwanted impacts, both immediate and long-term. Therefore, management of biofouling on SSAS has a range of potential benefits that can improve structure functions, cost-efficiency, sustainability, productivity, and biosecurity. This review and synthesis collates the range of methods and tools that exist or are emerging for managing SSAS biofouling for a variety of sectors, highlighting key criteria and knowledge gaps that affect development, and uptake to improve operational and environmental outcomes. The most common methods to manage biofouling on SSAS are mechanical and are applied reactively to manage biofouling assemblages after they have developed to substantial levels. Effective application of reactive methods is logistically challenging, occurs after impacts have accumulated, can pose health and safety risks, and is costly at large scales. Emerging technologies aim to shift this paradigm to a more proactive and preventive management approach, but uncertainty remains regarding their long-term efficacy, feasibility, and environmental effects at operational scales. Key priorities to promote more widespread biofouling management of SSAS include rigorous and transparent independent testing of emerging treatment systems, with more holistic cost-benefit analyses where efficacy is demonstrated.

The search for effective yet environmentally friendly strategies to prevent marine biofouling is hampered by the large taxonomic diversity amongst fouling organisms and a lack of well-defined conserved molecular targets. The acetylcholinesterase enzyme catalyses the breakdown of the neurotransmitter acetylcholine, and several natural antifouling allelochemicals have been reported to display acetylcholinesterase inhibitory activity. Our study is focussed on establishing if acetylcholinesterase can be used as a well-defined molecular target to accelerate discovery and development of novel antifoulants via sequential high-throughput in silico screening, in vitro enzymatic studies of identified compound libraries, and in vivo assessment of the most promising lead compounds. Using this approach, we identified potent cholinesterase inhibitors with inhibitory concentrations down to 3 μM from a 10,000 compound library. The most potent inhibitors were screened against five microfouling marine bacteria and marine microalgae and the macrofouling tunicate Ciona savignyi. No activity was seen against the microfoulers but a potent novel inhibitor of tunicate settlement and metamorphosis was discovered. Although only one of the identified active cholinesterase inhibitors displayed antifouling activity suggesting the link between cholinesterase inhibition and antifouling is limited to certain compound classes, the study highlights how in silico screening employed regularly for drug discovery can also facilitate discovery of antifouling leads.

Unwanted biofouling and predatory pests are a universal problem threatening aquaculture productivity and profitability. Various control approaches have been trialled, but industry uptake has been elusive due to the typically fine balance between pest and bivalve physiological tolerances (i.e., 'therapeutic window') and operational challenges related to infrastructure, scalability, and quality control. This study aimed to address these factors for acetic acid (AcOH), arguably the best-studied and most broadly applicable reactive treatment for bivalve aquaculture. Using case studies of farmed New Zealand green-lipped mussels (Perna canaliculus Gmelin 1791) and Pacific oysters (Crassostrea gigas Thunberg 1793), AcOH tolerances of various size classes of these bivalves were determined in a series of laboratory experiments, and cross-referenced to corresponding data for biofouling and predatory pests. Resulting 'therapeutic windows' formed the basis of provisional treatment parameters, being 2% AcOH for 60 s or 4% AcOH for 30 s for P. canaliculus and C. gigas, respectively. Three independent field experiments on operational P. canaliculus and C. gigas farms subsequently served to refine and validate the treatment parameters and associated operational procedures. For P. canaliculus, AcOH treatment had overall positive impacts on commercially relevant measures of aquaculture production, with the best performing treatment regimens of 1% or 2% AcOH for 60 s resulting in almost three times as many individual P. canaliculus per section of growing rope. Incorporating a subsequent air-drying step was also shown to reduce required AcOH immersion times, providing opportunities to enhance operational efficiencies via more rapid treatments. The provisional treatment parameters for C. gigas of 4% AcOH for 30 s were also highly effective against biofouling pests in the field and resulted in no detectable mortality of the culture species. Overall, this study demonstrates the utility of carefully refined and validated AcOH treatments to control problematic pests in bivalve aquaculture. It is essential to accurately determine 'therapeutic windows' for any given bivalve culture species and developing understanding of crop-pest interactions would better inform treatment timing and frequency. Such approaches could feed into wider frameworks to optimally manage pests below economically damaging thresholds, with AcOH ideally being one option in an arsenal of management interventions.

Internal seawater systems (ISS) are critical to the proper functioning of maritime vessels. Sea water is pumped on board ships for a broad array of uses, primarily for temperature control (e.g., engine and electrical systems), cooling capacity (e.g., air conditioners and refrigeration), and water provision (e.g., drinking, firefighting, steam, and ballast). Although sea water may spend only a brief period within ISS of a vessel, it can carry microorganisms and larval stages of macroorganisms throughout the system leading to biofouling accumulation that can impair system function or integrity. ISS can also act as a sub-vector of species translocations, potentially facilitating biological invasions. This review describes ships' ISS with a focus on operational impacts of biofouling and current drivers and barriers associated with ISS biofouling management. As ISS internal components are difficult to access, reports and studies of ISS biofouling are uncommon and much of the dedicated literature is decades old. The impact of biofouling on ISS and vessel operations is based on increased surface roughness of pipework and equipment, restricted water flow, corrosion and subsequent component impingement, reduced surface functional efficiency, and potential contamination by pathogens that can affect human and aquatic animal health. Biofouling management is primarily achieved using antifouling coatings and marine growth prevention systems, but independent and accessible data on their efficacy in ISS remain limited. Further research is required to resolve the extent to which biofouling occurs in ISS of the modern commercial fleet and the efficacy of preventive systems. Such information can ultimately inform decisions to improve operational efficiency for vessel operators and ensure any biosecurity risks are appropriately managed.