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The National Marine Sanctuary Foundation (the Foundation) is developing a new Blue Economy program and associated strategy to help envision and provide sustainable revenue generation for the benefit of Sanctuary conservation work across our nation’s 15+ Sanctuaries. This Blue Economy Strategy will be first applied within the Florida Keys National Marine Sanctuary in support of its Mission: Iconic Reefs restoration initiative, by building critical revenue-generating initiatives that also support restoration work. Within this first overarching Florida Keys application, work will center around the native Caribbean king crab and its potential to become a novel fishery alongside its primary purpose as a coral reef restoration species. This project will contribute to the Florida Keys application of the Foundation’s Blue Economy Strategy by providing critically necessary background market analysis research for a viability study of the Caribbean king crab (CKC) fishery within the Florida Keys.

In 2017, the Chilean government through the Chilean Economic Development Agency (CORFO) (an agency under the Ministry of Economy) launched a public call for the execution of a Technological Program to adopt, adapt, and/or developing enabling technologies for the development of Ocean Aquaculture in places with high-energy (strong waves, winds and/or currents). The consortium of companies, technology centers, and universities led by Ecosea Farming (Ecosea), focused its efforts on aspects related to structural engineering, mooring systems, sensors, Internet of Things (IoT), and other integral components, as well as essential aspects of regulation and standards. On this last topic, intensive collaborative work was carried out between the technical teams of the Andrés Bello University, the Undersecretariat of Fisheries and Aquaculture (Subpesca), the National Fisheries and Aquaculture Service (Sernapesca), and CORFO, with the aim of gathering relevant information from international experience, and establishing the main differences between aquaculture traditionally developed in the fjords, coast, estuaries, and inland sea of southern Chile and aquaculture in the high seas - a practice not yet clearly defined and still indistinctly known as offshore or open ocean aquaculture. This document summarizes the main findings obtained and can be a useful guide for future experiences in other countries with important aquaculture developments. [ABSTRACT FROM AUTHOR]

Antibiotics can be introduced from aquaculture facilities into marine sediments, where they may affect benthic communities and generate antimicrobial resistance (AMR). Antibiotics can be used in tandem with antiparasitics, and the effects of their combined usage could affect AMR patterns and transmit antibiotic resistance genes. This study compiles patterns of antibiotic and antiparasitic drug usage from 2016 to 2021 in British Columbia, New Brunswick, Newfoundland and Labrador, and Nova Scotia (Canada) and compares them internationally. There is an overall reduction in rates of antibiotic use per fish produced in Canadian aquaculture sites from 2016 to 2021. Compared to other salmon-producing countries, Canadian antibiotic rates per tonne of fish are lower than in Chile, but higher, on average, than in Norway and Scotland. Florfenicol (FLO) and oxytetracycline (OTC) are the prevalent antibiotics used in most salmon-producing countries, including Canada. We also note that <30% of sites used two drugs per year and <18% of sites used three drugs, with most of these sites using one antibiotic and one antiparasitic. There is an increase in FLO and a decrease use in OTC use in Canada, which could be positive environmentally considering FLO's lower dose and environmental persistence. The east and west coasts show comparable antibiotic rates, with an average rate of 78 mg/kg in BC and 76 mg/kg in the Atlantic provinces; however, they have differences in the type of antibiotic (average use of OTC: BC 38 mg/kg vs. Atlantic 214 mg/kg; average use of FLO: BC 40 mg/kg vs. Atlantic 10 mg/kg). Other distinctions between coasts include variation in the timing of treatments, with seasonal use in the Atlantic provinces (May–November) and year-round use in BC. This pattern is likely influenced by differences in water temperature and, subsequently, potential susceptibility to aquatic diseases. Disease prevalence and veterinarian choice/preferred treatments are factors that, we hypothesize, may impact treatment choice; however, additional information is required to adequately comment on this point. This data compilation includes spatial descriptions that could be used for area prioritization in future studies. [ABSTRACT FROM AUTHOR]

As the main component of the anchorage system in marine aquaculture facilities, the anchor pile is key to ensuring safety and stability. However, conventional monopiles have limited capacity to withstand uplift forces, thus rendering them susceptible to deviations and potentially causing damage to facility structures. Hence, a new winged monopile is proposed to improve and optimize the anchor pile. In this study, laboratory experiments are conducted to investigate the effect of load inclination angle (θ = 0°, 30°, 45°, and 60°), wing length (L = 30, 50, and 70 mm), and wing width (W = 10, and 20 mm) on the uplift resistance capacity of anchor piles in silty clay. The results show that: the winged monopile exhibits at least a 15% improvement in uplift performance compared with the conventional monopile (without wings) when the smallest wing plate parameters are selected (W = 10 mm, L = 30 mm). Additionally, the effect of the wing width on the uplift resistance under an oblique load is more evident than that of the wing plate length. As the area of the wing plate increases, the range of improved wing plate efficiency first increases, and then gradually decreases. This study can be used as a reference for the design optimization of uplift piles and the construction of marine aquaculture. [ABSTRACT FROM AUTHOR]

The Benguela upwelling region on the west coast of South Africa/Namibia has the only major kelp forests on the African continent. South Africa has four species of laminarian kelps; Ecklonia maxima, Laminaria pallida dominate kelp forests in the west coast Benguela upwelling system, with Macrocystis pyrifera occurring rarely in this region and Ecklonia radiata largely confined to the more nutrient-poor south and east coasts. Growth studies on these species have been limited to laboratory experiments and very few initial, small-scale coastal studies. As in other Atlantic regions, there is growing interest in the potential for kelp aquaculture in Southern Africa, and recent pilot initiatives. A comprehensive summary of available literature on South African kelps, their biology and ecology, distribution and growth parameters, is presented, and the potential for kelp aquaculture discussed in relation to recent developments elsewhere on Atlantic and Eastern Pacific coastlines. Recommendations are made with respect to the choice of potential species and sites. [ABSTRACT FROM AUTHOR]

Simple Summary: This study focuses on how Tasmanian sea-farmed Atlantic salmon respond to a natural infection with a parasite that causes amoebic gill disease (AGD), a major health issue for salmon globally. The research aimed to understand the progression of the disease by examining the salmon's gills at different stages of the outbreak and evaluating their response to freshwater treatment. The study employed both macroscopic and microscopic examinations of gills, as well as molecular tools to measure the abundance of amoebae and the expression of specific genes that indicate inflammation. Key findings showed a strong correlation between different measures of gill health and significant differences between distinct stages of AGD. After treatment, a varied response among the fish was observed, indicating that management strategies need to account for individual genetic, environmental, and health factors. The expression patterns of some inflammation-related genes highlight their potential as biomarkers for early detection of gill damage in salmon aquaculture worldwide. The results of this research are important as they can help develop better ways to detect and manage this disease early, potentially reducing losses in salmon farming and ensuring the sustainability of this vital food resource. Gill health has become a significant global challenge for Atlantic salmon (Salmo salar) aquaculture, particularly during the marine phase of farming. The increasing prevalence of gill pathologies has been linked to rising seawater temperatures, underscoring the need to evaluate existing tools for monitoring gill health and to develop novel approaches for early detection. In this study, we investigated the gill responses of commercially farmed Atlantic salmon to natural infection with Neoparamoeba perurans during an outbreak of amoebic gill disease (AGD) in Tasmania. Our focus spanned the low AGD prevalence, high AGD prevalence, and post-freshwater treatment stages of the outbreak. Evaluations of gill tissue included assessments of the gross AGD score, histopathological score, abundance of N. perurans (measured by 18S rRNA gene expression), and expression levels of inflammation-related transcripts. We demonstrated a strong correlation between different measures of AGD-related gill pathology and significant differences between distinct stages of the N. perurans outbreak. Post-treatment, fish exhibited considerable variability in their responses to the freshwater bath, highlighting the necessity for personalized management strategies that consider genetic, environmental, and health status factors. The expression patterns of angiogenin-1 (ANG1) and complement C1q tumour necrosis factor-related protein 3-like (C1QTNF3) emphasize their potential as biomarkers for early detection of gill damage in salmon aquaculture worldwide. [ABSTRACT FROM AUTHOR]

Climate change has presented a serious problem in recent times, which is why a new approach is being sought in terms of aquacultural food quality. In this study, the influence of temperature increase (by 2 °C) and pH decrease (by 0.2) was investigated on the queen scallop, Aequipecten opercularis (Linnaeus, 1758). Furthermore, the effect of a food-enriched diet with the probiotic culture Lactiplantibacillus plantarum I was assessed in climate-changed conditions. Scallops' morphometric parameters were measured before the experimental setup and after one month of being kept in controlled conditions. Morphometric parameters included the elongation index, compactness index, convexity index, density index, condition index, meat yield, gonadosomatic index, adductor muscle index, and hepatosomatic index. Climate-changed conditions had no effect on the scallop condition index, meat yield, or hepatosomatic index. Nevertheless, the addition of probiotics to their diet had a positive effect on the queen scallops cultivated under conditions of climate change, influencing positive allometry and the increase of the gonadosomatic indices. On the other hand, the same conditions negatively affected the adductor muscle index of the scallops. To conclude, in the context of climate change conditions, queen scallops could be a good organism of choice that can be very well adapted to the changed environmental conditions, especially with the addition of the lactic acid bacteria culture Lpb. plantarum I. [ABSTRACT FROM AUTHOR]

Infectious salmon anemia virus (ISAV) is an important pathogen in global Atlantic salmon (Salmo salar L.) aquaculture. The existence of both non-pathogenic (ISAV-HPR0) and pathogenic (HPR-deleted ISAV) forms of the virus impacts hatchery management. In November 2016, fish tested positive for ISAV-HPR0 at the National Cold Water Marine Aquaculture Center in Maine. A cohort exposed to the fish testing positive for ISAV were lethally sampled over a 7-month period (February–August 2017). No positive samples were detected during this time. Additional testing aimed to determine the extent of the ISAV infections in the facility's fish and to investigate the water sources as potential virus entry points. Fish testing was designed to detect 2% pathogen prevalence with 95% confidence (assuming diagnostic sensitivity of 85%). Over a three-year period, ISAV-HPR0 was detected in spawning fish annually and once in smolts. Repeat testing of smolts from the affected tank three weeks later failed to detect ISAV-HPR0. Over a one-year period of weekly or biweekly evaluation of the incoming water sources, ISAV was never detected. These findings suggest that ISAV-HPR0 infections in monitored hatchery populations can evade detection and that episodes of high prevalence of ISAV-HPR0 associated with spawning can be highly transient. In both cases, conventional surveillance based on recurrent testing of healthy populations may provide only a very limited indication of the HPR0 status. Instead, targeting surveillance to periods of physiological stress, such as spawning and smoltification, and adjusting the sample sizes to account for a related surge in prevalence, should enhance the detection capacity in hatchery settings while also reducing testing costs. [ABSTRACT FROM AUTHOR]

The present study aimed to address the issue of pressure on the remaining populations of the critical endangered species, fan mussel, Pinna nobilis, in the Eastern Mediterranean. Marine professional (shell/fish farmers, divers, fishers, administrators, etc.) stakeholders' knowledge (n = 151) in Greece reports that there was a reduction (81.6%) of the P. nobilis individuals during the last 15 years, especially in the years 2010–2012 and 2017–2018. Species' abundance decline is significantly (ρ = 0.293, p < 0.05) correlated over the last 5 years with the observed natural ecosystem degradation. Participants also stated that the main cause was pathogens alone (28.8%) or in combination with (illegal) fishing (17.1%) or pollution (14.4%). Additionally, 88% of them supported a total prohibition on the use of fan mussels for commercial purposes in order to restore stock levels.; 72.4% stated claimed that no appropriate control was in place and that they (>59.4%) were unsure if this monitoring control is carried out by the competent authorities. Marine stakeholders consider the importance of the species for biodiversity preservation (56.1%), environmental education (35.1%), and diving parks (29.7%). They declared that it is important to record-observe P. nobilis conservation reserves regions (42.6%), monitor areas of responsibility (39.9%), participate in the information society/use of social networks (38.5%), and participate in informational meetings (37.9%). The lack of interest among shell/fish farmers to contribute to P. nobilis on-growing farming indicates the ignorance to the potential benefits of the valuable ecosystem services provided by aquaculture through biodiversity conservation. Nevertheless, there is a demand for promoting the "conservation aquaculture" concept through its incorporation into marine farming activities supplementary to their core business in "production". [ABSTRACT FROM AUTHOR]

To improve the quality and quantity of seaweed mariculture harvests, seedlings are frequently introduced from regions geographically apart from cultivation sites. The effects of such introduction have been insufficiently studied, despite increasing demands on seaweed cultivation as a measure against global warming. We here evaluated the degree of cryptic invasion occurring through mariculture using a brown algal species, Undaria pinnatifida. Cultivated materials used in the Seto Inland Sea, Japan, were introduced from northern Japan in the 1970s. Based on the clear genetic structure among Japanese Undaria populations, we compared mitochondrial haplotypes between wild populations and cultivated materials in the Seto Inland Sea. All cultivated materials analyzed had haplogroups native to northern Japan. Multiple haplogroups were observed in the wild populations, especially those in the eastern Seto Inland Sea, which is exceptional considering the reported genetic structure. Some northern Japan haplotypes were observed both in cultivated materials and wild individuals. A northern Japan haplogroup was predominant at several sites near Undaria-cultivation sites. These results strongly suggested that cryptic invasion through Undaria mariculture occurred here, although its ecological impact remains unclear. There is a clear risk of invasion by mariculture seedlings from other regions, even when native conspecific populations are present. [ABSTRACT FROM AUTHOR]

The larval development of cowries has remained underexplored due to challenges associated with restricted growth and high mortalities, and as a result, their larvae never achieve competency or metamorphosis. In this study, we conducted a series of experiments using Cypraea tigris larvae to optimise the culture protocols. Broadly, there were no apparent differences in larval survival rates among the seawater quality levels (0.2, 1 aged, 50 μm filtered seawater). In contrast, a microalgal diet solely of Tisochrysis lutea and a mixed diet of Rhodomonas salina + Chaetoceros mulleri had higher larval survival rates than two other mixed diets (i.e., T. lutea + Tetraselmis suecica and T. suecica + R. salina). The provision of 10 ppm of the antibiotic streptomycin sulphate also boosted larval survival by preventing ciliate infection and minimising bacterial growth. We subsequently improved culture protocols by applying new information from these experiments and report the first successful captive breeding of C. tigris through to settlement. The C. tigris larvae reared at 28°C attained competency as early as 40 days post-hatching and metamorphosed by 42 days upon transfer to a well-conditioned tank. Observations of C. tigris larvae and early-stage juvenile development were documented for the first time and are reported herein. [ABSTRACT FROM AUTHOR]

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

Increased interest in marine fish farming in the United States has led to a need for fundamental economic information on production of candidate species for commercialization in various production systems. Funding for the project targeted those species with potential for production in southern tier states in the United States. Sufficient technical data were found to develop comprehensive budget analyses to estimate growout production costs for four scales of production for each of 10 species with potential for production in ponds, 13 in recirculating aquaculture systems (RAS), and five in net pens. The choice of species/production system scenarios was based on evidence of successful production on farms or in research. Estimation of production costs with enterprise budgets can provide useful guidance to identify the types of improved efficiencies that have the greatest effect on economic viability even when commercial farm data are not available. Commercial farm data were used where available, but for most species, data were available only from studies conducted under research conditions. Per‐kg costs of production were lowest for net pen production, followed by ponds, with production costs in RAS two to five times greater than in ponds or net pens. Ponds and net pens generally exhibited greater efficiency of use of capital assets across species than did RAS that resulted in lower percentages of fixed costs and lower annual costs per kg of fish produced. All five species evaluated for net pen production were estimated to be profitable, including redfish, Sciaenops ocellatus (also known as red drum), striped bass, Morone saxatilis, cobia, Rachycentron canadum, red snapper, Lutjanus campechanus, and seriolids (generic budget for almaco jack, Seriola rivoliana, California yellowtail, Seriola lalandi, and greater amberjack, Seriola dumerili), four in ponds (redfish, hybrid drum, ♀Pogonias cromis × ♂Sciaenops ocellatus, black sea bass, Centropristis striata, and cobia), but none of the RAS scenarios showed profitability at average yields (kg/cubic meter) reported in the literature. Comprehensive data on growout production of marine finfish species in the United States is generally lacking, and there is a strong need for production trials conducted under near‐commercial conditions with an endpoint of market‐sized fish. Production trials should be conducted in ponds (≥0.1 ha), net pens, and RAS tanks of a size that simulate commercial production conditions. Adequate production trial databases would provide opportunities to develop economic optimization models that would provide useful guidance for prospective producers. Average yields (kg/cubic meter) in RAS will need to be much greater than currently reported in the research literature for RAS production to be economically sustainable. Net pen production appears to be profitable in the United States, but effective permitting procedures are not in place. Providing research support for the US redfish sector that has developed effective production and marketing models could serve as a foundation for developing additional species and offer opportunities for diversification on marine finfish farms. [ABSTRACT FROM AUTHOR]

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Marine coastal resources are crucial to Tanzania's socio‐economic development and are a lifeline for the livelihoods and incomes of coastal communities. This study provides an overview of the coastal development of mariculture in mainland Tanzania and suggests future development strategies. The review article covers extensive reports available through field interviews, government policy documents, library literature searches and field work carried out by the authors. Despite the immense potential of mariculture to improve food security for localcommunities, its development has been uneven. Specifically only seaweed farming has advanced to commercial‐scale production. Other mariculture activities, such as finfish farming (e.g. milkfish, silver pompano), shellfish farming (e.g. prawn, mud crab and half‐pearl) and sea cucumber farming, are underdeveloped and confined to small‐scale operations. Locally consumed finfish, such as milkfish and pompano, have not attracted investors out of fear that the recovery of investment may not be achieved due to the low prices offered in the market. In this context, the sustainable use of coastal resources through mariculture becomes paramount to alleviating poverty and facilitating controlled migration from rural to urban. This comprehensive review explores the historical evolution and current status of mariculture initiatives in the coastal waters of mainland Tanzania, which presents a crucial aspect of the socio‐economic development of the nation. With declining global capture fisheries production and a growing demand for fish protein, Tanzania has strategically embraced mariculture as a viable alternative. The article traced the development of mariculture since the 1970s, highlighting past and current initiatives managed by government agencies, non‐government organizations and the private sector. Notable successes, such as seaweed culture, are highlighted along with the challenges that hinder the growth of marine farming activities. The review integrates insights from a comprehensive survey in coastal Tanzania, focusing on mariculture activities and collecting information on people who have stopped such practices, elucidating reasons for quitting. By consolidating experiences from past and present mariculture initiatives, this review provides valuable guidance for decision‐making towards promoting sustainable mariculture that supports coastal communities while preserving marine biodiversity. [ABSTRACT FROM AUTHOR]

Efficient multiple target tracking (MTT) is the key to achieving green, precision, and large-scale aquaculture, marine exploration, and marine farming. The traditional MTT methods based on Bayes estimation have some pending problems such as an unknown detection probability, random target newborn, complex data associations, and so on, which lead to an inefficient tracking performance. In this work, an efficient two-stage MTT method based on a YOLOv8 detector and SMC-PHD tracker, named EMTT-YOLO, is proposed to enhance the detection probability and then improve the tracking performance. Firstly, the first detection stage, the YOLOv8 model, which adopts several improved modules to improve the detection behaviors, is introduced to detect multiple targets and derive the extracted features such as the bounding box coordination, confidence, and detection probability. Secondly, the particles are built based on the previous detection results, and then the SMC-PHD filter, the second tracking stage, is proposed to track multiple targets. Thirdly, the lightweight data association Hungarian method is introduced to set up the data relevance to derive the trajectories of multiple targets. Moreover, comprehensive experiments are presented to verify the effectiveness of this two-stage tracking method of the EMTT-YOLO. Comparisons with other multiple target detection methods and tracking methods also demonstrate that the detection and tracking behaviors are improved greatly. [ABSTRACT FROM AUTHOR]

Several exogenous probiotics are applicable in fish culture; however, challenges in isolation and verification have hindered the full utilization of numerous host probiotics. Therefore, this study aimed to apply the host probiotic Exiguobacterium acetylicum G1-33 to hybrid grouper (Epinephelus fuscoguttatus ♀ × Epinephelus lanceolatus ♂) cultures and explore its mechanism of action. In total, 360 hybrid grouper were divided into four groups, which were fed the following for 60 days: three received commercial feed with varying concentrations of E. acetylicum G1-33 (106, 108, and 1010 CFU/g), while a control group received commercial feed. The results showed that supplementation with 106 and 108 CFU/g of E. acetylicum G1-33 enhanced gut morphology, upregulated growth-related genes (ghr1, igf-2, s6k1, tor), and promoted growth, with supplementation with 108 CFU/g resulting in the most notable enhancement. However, supplementation with 1010 CFU/g inhibited growth, possibly because of changes in intestinal morphology. Additionally, supplementation with E. acetylicum G1-33 upregulated the expression of immune-related genes (c3, myd88, Cu/Zn-sod, tlr3, and tnf2) in the liver and head kidney but led to an increase in malondialdehyde content, as well as a decrease in alkaline phosphatase and acid phosphatase activities, in the liver and serum, indicating increased oxidative stress. Moreover, supplementation with 106 and 108 CFU/g E. acetylicum G1-33 enhanced the widespread expression of immune-related genes in the head kidney and liver, respectively, and improved resistance to Vibrio harveyi, whereas supplementation with 1010 CFU/g weakened this resistance. In conclusion, E. acetylicum G1-33, particularly at 108 CFU/g, emerged as an effective probiotic, optimizing growth performance and immunity in hybrid grouper. This research is pioneering in its application of E. acetylicum in mariculture, potentially broadening the range of probiotic strategies in aquaculture. [ABSTRACT FROM AUTHOR]

Vibrio spp. are major pathogens responsible for mortality and disease in various marine aquaculture organisms. Effective disease control and genetic breeding strategies rely heavily on understanding host vibriosis resistance mechanisms. The Chinese tongue sole (Cynoglossus semilaevis) is economically vital but suffers from substantial mortalities due to vibriosis. Through continuous selective breeding, we have successfully obtained vibriosis-resistant families of this species. In this study, we conducted RNA-seq analysis on three organs, including liver, spleen and intestine from selected resistant and susceptible tongue soles. Additionally, we integrated these data with our previously published RNA-seq datasets of skin and gill, enabling the construction of organ-specific transcriptional profiles and a comprehensive gene co-expression network elucidating the differences in vibriosis resistance. Furthermore, we identified 12 modules with organ-specific functional implications. Overall, our findings provide a valuable resource for investigating the molecular basis of vibriosis resistance in fish, offering insights into target genes and pathways essential for molecular selection and genetic manipulation to enhance vibriosis resistance in fish breeding programs. [ABSTRACT FROM AUTHOR]

For freshwater or marine fish farming to be successful, live fish must be transported. This can be performed with eggs, larvae, juveniles, and adults. Nonetheless, because of the handling, confinement, and duration of transport, it is considered a difficult procedure. To prevent significant physiological changes that could result in fish mortality, it is crucial to look for ways to reduce stress and enhance the quality of transport water. Consequently, a comprehensive range of research on the use of additives in water, including salt and artificial or natural anesthetics, is presented in this review, which also discusses potential changes in water quality factors during transport, such as dissolved oxygen (DO), carbon dioxide (CO2), pH, ammonia, and temperature. The usage of stocking densities during transport is also covered in this review, with consideration given to the various recommendations for each species, fish size, and length of transport. [ABSTRACT FROM AUTHOR]

Simple Summary: Winter-associated mortalities at Atlantic salmon marine aquaculture sites have been reported in the last decade in Atlantic Canada and Iceland. Some fish species develop a condition known as 'Winter Syndrome' or 'Winter Disease' (WS/WD) when held at cold temperatures that is associated with enlarged and pale livers (fatty liver disease; FLD). To determine if salmon can develop FLD, we measured liver fat content and composition, and the expression of 34 molecular biomarkers of FLD in fish held long-term at 3 °C. Total fat and triacylglycerol levels were 50% higher in fish that showed symptoms of FLD, compared with healthy fish. Also, the expression level of 32 of the 34 selected biomarkers changed in fish with symptoms of FLD. Our results show that prolonged exposure to cold temperatures can lead to the development of FLD in some Atlantic salmon, and suggest that the development of new diets may improve the health and welfare of salmon during the winter. Large-scale mortality events have occurred during the winter in Atlantic salmon sea cages in Eastern Canada and Iceland. Thus, in salmon held at 3 °C that were apparently healthy (i.e., asymptomatic) and that had 'early' and 'advanced' symptoms of 'winter syndrome'/'winter disease' (WS/WD), we measured hepatic lipid classes and fatty acid levels, and the transcript expression of 34 molecular markers of fatty liver disease (FLD; a clinical sign of WS/WD). In addition, we correlated our results with previously reported characteristics associated with this disease's progression in these same individuals. Total lipid and triacylglycerol (TAG) levels increased by ~50%, and the expression of 32 of the 34 genes was dysregulated, in fish with symptoms of FLD. TAG was positively correlated with markers of inflammation (5loxa, saa5), hepatosomatic index (HSI), and plasma aspartate aminotransferase levels, but negatively correlated with genes related to lipid metabolism (elovl5b, fabp3a, cd36c), oxidative stress (catc), and growth (igf1). Multivariate analyses clearly showed that the three groups of fish were different, and that saa5 was the largest contributor to differences. Our results provide a number of biomarkers for FLD in salmon, and very strong evidence that prolonged cold exposure can trigger FLD in this ecologically and economically important species. [ABSTRACT FROM AUTHOR]

SUMMARY: The significant concentrations of phosphate in wastewater can be considered as an important fertilizer source. Some microalgae uptake phosphate from wastewater and store it in the form of polyphosphate (polyP). Therefore, biological phosphorus recovery processes have been attracting significant attention recently. However, wastewaters are often rich in ammonium, and so microalgae used for phosphorus recovery should be tolerant of this component. In the present study, 151 microalgae were isolated from freshwater, brackish water and seawater. Among them, 11 strains showed higher growth rates in ammonium‐rich media. Of these, the strain SLG4‐06 originating from a marine environment showed the highest polyP accumulation rate and was selected as the most potential alga for phosphorus recovery from wastewater. Based on the morphological and ultrastructural characteristics and phylogenetic analyses of nuclear‐encoded 18S rDNA and chloroplast‐encoded rbcL of strain SLG4‐06, we propose Picochloropsis malayensis gen. et sp. nov. for this strain in the Chlorellales, Trebouxiophyceae. Because P. malayensis can grow in both seawater and freshwater environments, it may be suitable for wastewater treatment in marine aquaculture ponds with widely fluctuating salinity levels. [ABSTRACT FROM AUTHOR]

Madagascar's seagrass meadows are among the least-studied ecosystems in the western Indian Ocean region. To facilitate sustainable management, understanding the traditional uses of seagrass areas in relation to current management policies is necessary. This study assessed the uses of, and policies relevant to, seagrass ecosystems off southwestern Madagascar. We interviewed 131 community members in five coastal villages around the Bay of Ranobe in Toliara Province. Answers to the survey revealed a good level of awareness of seagrass, though 55% of respondents perceived the status of the seagrass areas as deteriorating. Opinions varied on the source or degree of threats to seagrass, but 74.8% of respondents suggested destructive fishing methods or other factors, including natural phenomena and animal grazing. The responses highlight that seagrass meadows serve as areas important for fishing, seaweed cultivation or sea cucumber farming, and the passage of boat/pirogue transportation. There are currently no tangible policies that directly protect or manage the seagrass areas regarding these activities, although some national regulations and local management initiatives are indirectly relevant, notably no-take zones and the local-level codes known as Dina. Development and implementation of a national management plan for seagrass ecosystems is a key gap. This demands the collection of scientific data to support decision-making to ensure long-term provision of the services provided by seagrass meadows. The involvement of coastal communities in the management of seagrass ecosystems will be necessary for the success of any new policies. [ABSTRACT FROM AUTHOR]

Research has focused on alternative plant materials or additives that can be used instead of fish meal due to limited stocks and increased feed prices, although it is important for carnivorous fish species. Taurine is a functional amino acid supplemented to low fish meal diets to improve the growth performance of fish. In this study, eight experimental diets with 0%, 0.5%, 1% and 2% ratios of taurine supplemented (T0, T0.5, T1 and T2) high (HFM) and low fish meal (LFM) diets were prepared (defined as HFMT0, HFMT0.5, HFMT1, HFMT2, LFMT0, LFMT0.5, LFMT1 and LFMT2). The experiment was carried out in twenty-four 400 L rectangular fiberglass tanks conducted in a marine water system, and fish (initial mean weight of 23.5 g) were stocked in each tank. The nutrition trial was carried out for 90 days with three replicates. Meagre fed with the HFMT1 diet had a higher final mean weight (FMW) and specific growth rate (SGR) than fish fed with HFMT0 and all LFM diets. Including taurine in all LFM diets also enhanced growth performance. The FMW and SGR of fish fed the LFMT0.5 diet were similar when compared to HFMT0 (P>0.05) and increased compared to that of other LFM diets with taurine (P<0.05). Meagre fed the LFM0.5 diet had a lower feed conversion rate (FCR) than those provided for all HFM diets, although there was no significant difference between treatments. Dietary taurine has decreased the hepatosomatic index (HSI), viscerosomatic index (VSI) and total ammonia-nitrogen excretion (TAN), irrespective of taurine and fish meal levels. Including dietary taurine at both fish meal levels enhances the number of red blood cells (RBC) and whole-body amino acids of meagre. The most remarkable conclusion of this study is the inclusion of taurine in low fish meal diets improved growth performance and profitability in meagre, and the level of 0.5% has been recommended. [ABSTRACT FROM AUTHOR]

The sciaenid meagre (Argyrosomus regius, Asso 1801) is a significant organism in fisheries and a promising candidate for the Egyptian aquaculture. This study presented a comparative analysis of wild and aquacultured meagre. Two size groups of fish, small (S) and large (L), from the Egyptian Mediterranean Sea and a local farm in Maryut Valley were examined. Oxidative stress markers and antioxidant responses, including superoxide dismutase (SOD), total antioxidant capacity (TAC), and catalase (CAT), were measured in the liver. Additionally, variations in muscle composition of lipids, total proteins, moisture, and ash content were evaluated. The muscle heavy metals (lead (Pb), cadmium (Cd) mercury (Hg), manganese (Mn) and nickel (Ni)) concentrations were analyzed, and total accumulation was assessed using the metal pollution index (MPI). Furthermore, assessments of hazard associated with fish ingestion were conducted based on estimated dietary intakes (EDI and EWI), the target hazard quotient (THQ) and the carcinogenic risk (CR). The muscle contents of moisture, ash, total lipids, and total protein revealed insignificant results. The liver of small farmed fish (SFM) exhibited higher levels of SOD, CAT, and TAC compared to other groups. Analysis of heavy metals showed a nonsignificant trend of higher accumulation of Ni in farmed and small-sized fish, while Pb, Cd and Hg levels were higher in wild fish. However all recorded heavy metals did not exceed the international guideline of maximum permissible limit (MPL) for human consumption. Metal estimated dietary intake was calculated, and non-carcinogenic and carcinogenic health risk was assessed for different studied groups. The calculated THQ for Pb, Cd, Mn and Ni were less than 1, indicating lack of health risks from consumption of single metal up to seven times per week. The CR level indicated safe levels of Pb, Cd, Ni and Hg in the flesh of meagre in the Egyptian water. [ABSTRACT FROM AUTHOR]

There is an international pressure to increase the worldwide expanse of marine mussel farms. However, the mussel farms are challenged with environmental problems such as mucilage aggregate events. Thus, it is essential to assess the effects of mucilage on the mussel aquaculture and to eradicate the harm and socioeconomic effects they confer on society. Our study addressed this issue by establishing a demographic baseline for commercially important mussel species prior to the proposed aquaculture in the area. This baseline was established at a recently set up commercial mussel farm located approximately 4km north of Erdek port and around 2km from Ocaklar port in the Marmara Sea region of Türkiye. Monthly samples of spats attached to the collectors and mussel meat yields were addressed, and seawater temperature and chlorophyll a contents were measured throughout this study (36 months) conducted at a commercial mussel farm. Year-round biological data from 2019 to 2022 were recorded before, during, and after the mucilage event on the Mediterranean mussel, Mytilus galloprovincialis. Moreover, samples were taken from an area inside the mussel aquafarm. As a result of this study, differences before, during, and after the mucilage aggregate event were detected in the number of the Mediterranean mussel spat attached to the collectors and the meat yields of the farmed mussels. This demographic baseline is the only data available, at a sufficient spatial and temporal resolution, for evaluating the effects of a mucilage aggregate event in the mussel aquafarm, and it fills an important data gap for risk assessment. [ABSTRACT FROM AUTHOR]

The Mediterranean Sea is a hotspot for the introduction of non-indigenous species. Among them, invasive alien species can seriously affect the areas they colonize, not only by altering the marine food webs and community structure, but also by harming certain economic activities, such as fishing, tourism, aquaculture and marine infrastructure. Rugulopteryx okamurae is a brown macroalga considered the fourth most harmful species among the 10 most invasive species reported in the Mediterranean; in fact, it has recently been included in the list of invasive alien species of Union concern due to its serious impact on biodiversity and socioeconomic implications. This species was reported for the first time in the Mediterranean in 2002 in Thau Lagoon (France), introduced by the aquaculture of the Japanese oyster Magallana gigas. Since then, this species has spread in both the Mediterranean and Atlantic Ocean with a strong invasive behavior, particularly along the Strait of Gibraltar. Rugulopteryx okamurae was also recently reported for the first time in Italian waters, in the Gulf of Palermo (Sicily). In this study, we report a record of this species further to the east, in the Ionian Sea, where it has not previously been recorded, and provide possible explanations of the spreading and arrival routes in this area. The rapid expansion of R. okamurae is raising concerns; thus, in order to safeguard native communities, it is crucial to keep monitoring this invasive species so that it is possible to regularly update its distribution and follow up on its spread dynamics in the Mediterranean basin. [ABSTRACT FROM AUTHOR]

Abalone is a popular mollusk in the marine aquaculture industry of China. However, existing challenges, like slow growth, individual miniaturization, and the absence of abundant abalone, have emerged as significant obstacles impeding its long-term progress in aquaculture. Studies have demonstrated that insulin-related peptide (IRP) is a crucial factor in the growth of marine organisms. However, limited studies have been conducted on IRP in abalone. This study indicated that the hdh-MIRP1 open reading frame (ORF) was composed of 456 base pairs, which encoded 151 amino acids. Based on the gene expression and immunofluorescence analyses, the cerebral ganglion of Haliotis discus hannai (H. discus hannai) was the primary site of hdh-MIRP1 mRNA expression. Moreover, hdh-MIRP1 expression was observed to be higher in the larger group than in the smaller group abalones. Only single nucleotide polymorphism (SNP) was related to their growth characteristics. However, approximately 82 proteins that may interact with hdh-MIRP1 were identified. The functional enrichment analysis of the 82 genes indicated that hdh-MIRP1 may be involved in the regulation of glucose metabolism and the process of growth. This study established a benchwork for further investigating the role of IRP in the growth of abalone. [ABSTRACT FROM AUTHOR]

Objective: We sought to evaluate several methods of operation of a foam fractionator for fine‐solids removal (organic matter < 55 μm) in a commercial‐scale, low‐salinity (11–13‰) recirculating aquaculture system (RAS) for marine finfish production. Methods: The total suspended solids (TSS) concentrations of the RAS microscreen drum filter inflow and outflow and the foam fractionator outflow were obtained under various foam fractionator operating conditions. The outflow TSS concentration of the drum filter also served as the inflow TSS concentration for the foam fractionator. Sample collection for TSS determination was divided into two categories: particles greater than 55 μm and particles less than 55 μm. The difference between inflow and outflow TSS concentrations was used to determine the removal percentage for each particle class of each unit. Additionally, the volume of foammate produced under operating conditions by the fractionator and the amount of solids contained within the foammate were quantified. Flow through the foam fractionator was also obtained to determine the amount of solids removed per volume of influent water treated. Result: The influent TSS concentration for the seven different operating conditions evaluated ranged from 4.8 to 6.3 mg/L, with the percentage of particles less than 55 μm ranging from 69.75% to as high as 86.1%. The drum filter removed over 90% of the particles larger than 55 μm and removed 8–26% of the particles smaller than 55 μm. No difference was observed in the overall removal efficiency of the drum filter, which ranged from 19% to 44%. There was no significant difference in the foam fractionator overall removal efficiency, which ranged from 6.5% to 38.5%. Operating the foam fractionator at a high water head height (HHH) with the submersible aspirating impeller provided the greatest removal percentage of particles less than 55 μm (26.9%). However, at the HHH, only half the amount of solids was removed compared to using a Venturi injector with ozone, but energy use was roughly 26% greater. Conclusion: The foam fractionator was operated at the HHH, about 0.31 m higher than the low water head height, for production operation. Additionally, Venturi injection of ozone provided the greatest removal of solids for the volume of influent water treated over a 12‐h operational period. The submersible aspirating impeller showed potential for low‐cost use with reasonable solids removal and warrants further evaluation. Impact statementAccumulation of fine solids and the removal thereof constitute an issue for commercial recirculating aquaculture system (RAS) production of marine finfish. This study evaluates the performance of a foam fractionator under various operational conditions with a Venturi injector and submersible aspirating impeller. Information from this work adds to base data for commercial‐scale units to support development of RAS marine finfish production in the United States. [ABSTRACT FROM AUTHOR]

Offshore wind turbines have rapidly scaled up in recent years, with plans to construct turbines up to 22 MW in the next decade. However, the operations and maintenance (O&M) requirements for these 'next‐generation turbines' remain largely unknown. In this study, the total O&M costs are calculated, using a bench‐marked O&M model, for a hypothetical 10 MW turbine scenario using two drive train configurations, based on known failure rates of smaller turbines. The O&M costs of the 10 MW turbines are compared with those of existing 3 MW turbines in two case studies: a North Sea wind farm and an East Coast US wind farm. Overall, direct drive 10 MW turbines performed better depending on the site's climate conditions. The study indicated that the two‐stage drive train configuration may be more suitable for the US site than the North Sea, depending on the turbine's failure rate. The US site benefited from increased availability due to more favourable weather windows, resulting in lower lost revenue for the two‐stage configuration despite high transport costs. The study found that the failure rate of 10 MW offshore wind turbines in the North Sea with a two‐stage gearbox can increase by as much as 30% compared to the 3 MW failure rates without increasing direct O&M costs. These findings are crucial for the offshore wind energy industry, particularly for OEMs, developers and maintenance providers, as they provide insights into the required reliability for next generation turbines to reduce O&M costs compared to existing 3 MW turbines. [ABSTRACT FROM AUTHOR]

This document is a summary of a special issue of the journal Aquaculture Economics & Management, which features seven articles presented at a conference on economics and marketing in the aquaculture industry. The articles cover a range of topics including production efficiency, profitability of new aquaculture species, risk management, marketing, consumer preferences, trade, policy, and the contribution of aquaculture to the regional economy. The papers provide insights into various aspects of aquaculture economics research, such as seafood trade, market integration, risk assessment, consumer preferences, and the development of new species and technologies. Overall, these papers contribute to the understanding and improvement of the aquaculture industry. [Extracted from the article]

The fish industry is an important source of income for island countries. Fish is a main source of animal-based protein. Marine fishing is gradually being replaced by marine farming (or aquaculture) due to declining wild fish populations and water pollution. However, fish farming is costly job with high requirements for labor, electricity, water, and feed. The use of deep learning to perform intelligent surveillance in aquaculture fields, reducing the need for human resources and implementing real-time monitoring, has been proposed. In this article, we propose a novel deep residual network (ResNeXt $3 \times 1 \mathrm{D}$) for abnormal behavior recognition in aquaculture fields. The proposed ResNeXt $3 \times 1 D$ convolutional network is mainly based on an $R(2+1) D$ convolutional network and modified to obtain better performance. Experimental results showed that the proposed ResNeXt $3 \times 1 D$ exhibited good performance for abnormal behavior recognition in aquaculture fields. Specifically, the accuracy obtained using the proposed ResNeXt $3 \times 1 \mathrm{D}$ for abnormal behavior recognition in aquaculture fields was approximately $95.3 \%$. [ABSTRACT FROM AUTHOR]

In aquaculture, it is crucial to understand and mitigate the carbon footprint for sustainable production. As demand for seafood increases, various production techniques compete for an eco-friendly status. This review examines the carbon footprint of various land-based marine aquaculture systems, highlighting their environmental impact. Through exploring innovations and best practices, it navigates the complexities of reducing emissions and promoting carbon sequestration. Some proposals for this purpose are based on diversification through low-trophic-level species, the preservation of high-carbon sequestration sites, polyculture, organic aquaculture and improvements in nutrition, feeding, waste and energy management. In this sense, some land-based aquaculture systems are progressively adapting and updating their zootechnical procedures. Recirculating Aquaculture Systems (RASs) offer interesting advantages such as water conservation, pollution reduction and biosecurity. Integrated Multi-Trophic Aquaculture systems (IMTAs) aim to address two major issues in aquaculture: efficient water usage and the environmental impact of effluents, which are rich in organic particles and dissolved nutrients from undigested food and feces; hence, these systems involve cultivating multiple species (polyculture). Biofloc Technology (BFT) is based on the formation of bioflocs in a culture medium. These systems can enhance feeding efficiency and waste management, thus optimizing nutrient utilization and minimizing environmental impact, achieved through reduced water and fertilizer usage. Traditional (extensive) aquaculture systems operate with minimal input of feed and chemicals, relying heavily on the natural productivity of the ecosystems; thus, the need for manufactured feed, the environmental impact associated with feed production and the transportation and overall costs are significantly reduced. Overall, while RASs, BFT and extensive systems in general offer significant sustainability benefits, IMTA's holistic approach to ecosystem management and nutrient recycling makes it, in our estimation, the most effective method in terms of ecological footprint in aquaculture. However, its quantitative evaluation is extremely complex, and there is currently a lack of references about its global carbon footprint. Therefore, further research and development are required, as well as collaboration and knowledge-sharing among stakeholders. [ABSTRACT FROM AUTHOR]

The cage method for the cultivation of the seaside scallop Mizuhopecten yessoensis is the most developed and popular method at sea farms in Primorsky Krai (Sea of Japan). However, this method of mollusk cultivation requires the careful planning of farming activities. Recently, mariculture farms in different countries have often encountered the mass mortality of cultured hydrobionts. The causes of such diseases are not quite clear, and often their identification requires a large amount of time and financial expenditure. Therefore, the use of predictive mechanisms based on biomarkers can help identify hidden threats in cultured scallop organisms that lead to mass mortality. In this study, we propose a rapid diagnostic method for predicting the distant mass mortality of M. yessoensis cultured in cages using biomarkers. The assessment of the pathological state of cultured mollusks at earlier developmental stages using the DNA comet method and oxidative stress markers (malondialdehyde) will allow the diagnosis and prediction of significant losses of marketable individuals in marine farms. In this study, we evaluated different age groups of mollusks cultured in the different water areas of Peter the Great Bay (Sea of Japan). During the study, we found that the death of cultured mollusks increased with increasing DNA damage and the active accumulation of malondialdehyde in tissues. It was observed that in scallops aged 1+ cultured in Severnaya Bay, high levels of DNA molecule damage and malondialdehyde were registered in the digestive glands and gills, which subsequently led to the death of almost all marketable individuals aged 3+. Therefore, the work is of significant value in assisting the aquaculture industry in solving the emerging problems of scallop farming and preserving marketable products. The proposed markers effectively reflect the condition of molluscs under extreme conditions caused by various factors, making them highly suitable for monitoring studies and forecasts on aquaculture farms. [ABSTRACT FROM AUTHOR]

In this study, in order to promote the development of far-reaching marine aquaculture equipment in an intelligent direction and solve the problems related to power supply, a tidal current energy harvesting device for a low-velocity sea area is proposed. For low-velocity waters in farming areas, the device can effectively harness tidal energy to provide a stable power supply to open sea cages. A mathematical model of the Savonius turbine blade is established, and the influence of the distance between the impeller center and the water surface on the energy capture efficiency of the turbine is analyzed through numerical simulation. Using ANSYS2021R1 software, the velocity field of the floating body is simulated, and the overall structure and anchoring system of the power generation device is designed. In order to verify the effectiveness of the power generation device, a test model is built and a physical model test is carried out. The variation in parameters related to the relative distance between the impeller and the water under different flow velocities is tested, and the test data are analyzed. The test results show that the floating body can increase the flow speed by 10%. Optimizing the blade number and order of the S-turbine can capture more than 20% of the energy. Under different flow velocities, the capture power of the impeller first increases and then decreases with increasing distance from the water. When the center of the impeller is one-quarter of the impeller diameter higher than the water surface, the output power of the impeller is at the maximum. This indicates that the proposed power generation device can effectively use tidal energy under different water depth conditions and provide a stable power supply for far-reaching marine aquaculture equipment. [ABSTRACT FROM AUTHOR]

This study examines the current status and future potential of the offshore wind sector. Offshore wind is pivotal in transitioning to a low-carbon society and meeting rising energy demands, despite being capital-intensive. The industry aims to develop larger-scale wind farms in deeper ocean locations, with projections indicating significant cost reductions. To explore deeper ocean areas, specialized foundations like floating platforms moored to the seabed are required. This study proposes helical piles anchored in the seabed as a method to secure mooring lines. Using Plaxis 3D, a parametric examination was conducted on helical piles with two plates: one fixed at the pile's toe and the other varying in position between 0.5 and 13 m from the seabed surface. Load inclination angles (0, 20, 40, and 60 degrees) were used to simulate mooring line loads. Results indicate the optimal Zh/Z ratios for maintaining load-bearing capacity and stability: 0.12 (10 mm movements), 0.22 (25 mm), and 0.26 (50 mm) for small shaft diameters; and 0.34 (10 mm), 0.38 (25 mm), and 0.46 (50 mm) for large shaft diameters. These findings highlight the importance of specific load inclination angles based on shaft diameter and allowable movement for effective performance. [ABSTRACT FROM AUTHOR]

Animal farming wastewater is one of the most important sources of ammonia nitrogen (NH4+-N) emissions. Electro-oxidation can be a viable solution for removing NH4+-N in wastewater. Compared with other treatment methods, electro-oxidation has the advantages of i) high removal efficiency, ii) smaller size of treatment facilities, and iii) complete removal of contaminant. In this study, a previously prepared DSA (W, Ti-doped IrO2) was used for electro-oxidation of synthetic mariculture and livestock wastewater. The DSA was tested for chlorine evolution reaction (CER) activity, and the reaction kinetics was investigated. CER current efficiency reaches 60–80% in mariculture wastewater and less than 20% in livestock wastewater. In the absence of NH4+-N, the generation of active chlorine follows zero-order kinetics and its consumption follows first-order kinetics, with cathodic reduction being its main consumption pathway, rather than escape or conversion to ClO3−. Cyclic voltammetry experiments show that NH4+-N in the form of NH3 can be oxidized directly on the anode surface. In addition, the generated active chlorine combines with NH4+-N at a fast rate near the anode, rather than in the bulk solution. In electrolysis experiments, the NH4+-N removal rate in synthetic mariculture wastewater (30–40 mg/L NH4+-N) and livestock wastewater (~ 450 mg/L NH4+-N) is 112.9 g NH4+-N/(m2·d) and 186.5 g NH4+-N/(m2·d), respectively, which is much more efficient than biological treatment. The specific energy consumption (SEC) in synthetic mariculture wastewater is 31.5 kWh/kg NH4+-N, comparable to other modified electro-catalysts reported in the literature. However, in synthetic livestock wastewater, the SEC is as high as 260 kWh/kg NH4+-N, mainly due to the suppression of active chlorine generation by HCO3− and the generation of NO3− as a by-product. Therefore, we conclude that electro-oxidation is suitable for mariculture wastewater treatment, but is not recommended for livestock wastewater. Electrolysis prior to urea hydrolysis may enhance the treatment efficiency in livestock wastewater. [ABSTRACT FROM AUTHOR]

The study examines the governance of low trophic species mariculture (LTM) using Sweden as a case study. LTM, involving species such as seaweeds and mollusks, offers ecosystem services and nutritious foods. Despite its potential to contribute to blue growth and Sustainable Development Goals, LTM development in the EU and OECD countries has stagnated. A framework for mapping governance elements (institutions, structures, and processes) and analyzing governance objective (effective, equitable, responsive, and robust) was combined with surveys addressed to the private entrepreneurs in the sector. Analysis reveals ineffective institutions due to lack of updated legislation and guidance, resulting in ambiguous interpretations. Governance structures include multiple decision-making bodies without a clear coordination agency. Licensing processes were lengthy and costly for the private entrepreneurs, and the outcomes were uncertain. To support Sweden's blue bioeconomy, LTM governance requires policy integration, clearer direction, coordinated decision-making, and mechanisms for conflict resolution and learning. [ABSTRACT FROM AUTHOR]

Abstract Background Vibriosis is one of the most serious bacterial diseases and causes high morbidity and mortality among cultured sea breams. This study was undertaken to track the surveillance of Vibrio infection and its correlation to environmental factors. A total of 115 gilthead sea breams were collected seasonally from a private earthen pond fish farm in the Shatta area of Damietta, Egypt from September 2022 to July 2023. Physicochemical parameters of water were analyzed, and heavy metal levels were measured. The fish samples were subjected to clinical, bacteriological, Enterobacterial Repetitive Intergenic Consensus (ERIC) fingerprinting, and hematoxylin and Eosin histopathological staining. Results The results revealed significant variations in the water quality parameters over different seasons, in addition to an increase in heavy metals. Naturally infected fish showed external signs and postmortem lesions that were relevant to bacterial infection. Two dominant Vibrio subspecies of bacteria were identified: V. alginolyticus (205 isolates) and V. fluvialis (87 isolates). PCR confirmed the presence of V. alginolyticus using the species-specific primer collagenase at 737 bp. The highest prevalence of V. alginolyticus was detected during the summer season (57.72%), and the lowest prevalence was observed in autumn (39.75%). The correlation analysis revealed a positive relationship between V. alginolyticus and water temperature (r = 0.69). On the other hand, V. fluvialis showed a high prevalence during the autumn season (25.30%) and the lowest prevalence during the summer season (10.56%), where it was negatively correlated with water temperatures (r =—0.03). ERIC fingerprinting showed genetic variation within the Vibrio isolates. Antimicrobial susceptibility testing revealed sensitivity to ciprofloxacin and doxycycline, and resistance to amoxicillin and erythromycin. The multiple antibiotic resistance (MAR) index values for V. alginolyticus and V. fluvialis ranged from 0.3 to 0.7, with a multi-drug resistance pattern to at least three antibiotics. Histopathological alterations in the affected tissues revealed marked hemorrhage, vascular congestion, and hemosiderosis infiltration. Conclusion This study provides insights into the potential propagation of waterborne diseases and antibiotic resistance in the environment. Ensuring that the environment does not serve as a reservoir for virulent and contagious Vibrio species is a critical concern for regional aquaculture industries. Therefore, we recommend implementing environmental context-specific monitoring and surveillance tools for microbial resistance.

The Pacific oyster (Crassostrea gigas) is a marine aquaculture species with rapid production growth in recent years. China accounts for nearly 90% of global production by 2021, especially in Shandong province. Evaluating suitability is crucial for ensuring the sustainable growth of Pacific oyster marine aquaculture and achieving a blue transition. This study developed a suitability evaluation model for Pacific oyster marine aquaculture using a Geographic Information System (GIS), Maximum Entropy (MaxEnt) model, remote sensing, and reanalysis data. A literature review and Analytic Hierarchy Process (AHP) were used to establish an evaluation model encompassing water quality, hydrology, climate and meteorology, and socioeconomic factors. The results showed that within a 20 km range of the Shandong coast, 49% of the area was highly suitable, 51% was moderately suitable, and the overall annual high score proportion (HSP) fluctuated around 50%, with higher suitability observed in the spring and autumn. The inner bays of the coastal areas (Laizhou, Rongcheng, Jimo) exhibited high suitability (HSP over 80%); in contrast, the offshore areas (Changdao, Rushan) farther from the coast had lower suitability and showed significant monthly variations. The result was consistent with the spatial distribution and temporal variation of Shandong’s existing Pacific oyster marine aquaculture areas. The study also found that El Niño significantly impacts Rongcheng, Rushan, and Jimo during summer. We predicted an overall increase of suitability in the Shandong offshore areas under future climate change scenarios, with a more significant increase of suitability in the north. El Niño-Southern Oscillation (ENSO) influenced the concentration of parameters such as chlorophyll-a (Chl-a) and total suspended sediment (TSS) in the coastal waters through its impact on precipitation (Pr), resulting in suitability fluctuations. [ABSTRACT FROM AUTHOR]

Ocean Negative Carbon Emission (ONCE) involves utilizing natural marine chemistry and biology, along with mariculture, to achieve carbon sink goals. Growing awareness of the interplay between aquaculture and the coastal carbonate system has drawn researchers’ attention amid ring CO2 concentrations and the negative impacts of aquaculture on the environment. In this study, twelve sites representing different maricultural types were selected, including macroalgae, shellfish, fish, and non-farming areas. The environmental factors, dissolved inorganic carbon (DIC), total alkalinity (TA), and pCO2, were measured monthly during kelp farming periods. Nitrate is a major component of total nitrogen, and the NO3-N concentration in the macroalgal culture zone was lower than others, indicating effective nitrogen removal by macroalgae aquaculture. TA and DIC in non-farmed areas demonstrated larger variation ranges than in farming areas, probably due to the effects of precipitation on salinity. Aquaculture activities effectively maintained TA and DIC, with macroalgae cultivation playing an important role in TA stability, potentially resisting acidification. The pCO2sea-air of macroalgae culture areas in spring was slightly negative, suggesting carbon sink potential. However, further research is needed to assess the full extent of this “fourth type” of blue carbon, including accurate carbon footprint calculation and the contributions of particulate organic carbon and recalcitrant dissolved organic carbon. This study provided insight into the comprehensive contribution of different aquaculture types to the fishery environment and carbonate system, which can help guide aquaculture management and facilitate the carbon-neutral transition of aquaculture. [ABSTRACT FROM AUTHOR]

With the continuous increase in global mariculture production and aquaculture areas, the environmental pollution caused by the mariculture industry is becoming increasingly serious. Faced with environmental issues, countries worldwide have formulated environmental regulations to scientifically intervene in marine environmental pollution issues and promote the green development of the mariculture industry. However, we must determine if strict environmental regulations can effectively promote the green development of the mariculture industry. This article uses the inter-provincial panel data of China's coastal areas from 2003 to 2019 as a sample. We use the entropy-technique for order of preference by similarity to ideal solution method to measure the intensity of environmental regulation in China's coastal areas and the level of green development of the mariculture industry. On this basis, an economic geography nested matrix was selected to construct a spatial panel econometric model to empirically explore the impact of environmental regulations on the green development of the mariculture industry. This approach also allows us to examine the heterogeneity of the impact of different types of environmental regulations on the green development of the mariculture industry. The research results indicate that environmental regulations have a "U-shaped" impact on the green development of the local mariculture industry, while they have an inverted "U-shaped" impact on the green development of the nearby mariculture industry. Furthermore, heterogeneity exists in the impact of different types of environmental regulations on the green development of the mariculture industry. Based on the research results, this article proposes policy recommendations from the perspectives of flexibly adjusting the intensity of environmental regulations, accelerating the development of voluntary-based environmental regulations, and regulating competition among local governments, which can provide decision-making references for the government to adjust environmental regulation policies and improve the level of green development in the mariculture industry. [ABSTRACT FROM AUTHOR]

The sandfish Holothuria (Metriatyla) scabra, is a high-value tropical sea cucumber harvested from wild stocks for over four centuries in multi-species fisheries across its Indo-Pacific distribution, for the global bê che-de-mer (BDM) trade. Within Southeast Asia, the Philippines is an important centre of the BDM trade, however overharvesting and largely open fishery management have resulted in declining catch volumes. Sandfish mariculture has been developed to supplement BDM supply and assist restocking efforts; however, it is heavily reliant on wild populations for broodstock supply. Consequently, to inform fishery, mariculture, germplasm and translocation management policies for both wild and captive resources, a high-resolution genomic audit of 16 wild sandfish populations was conducted, employing a proven genotyping-bysequencing approach for this species (DArTseq). Genomic data (8,266 selectively-neutral and 117 putatively-adaptive SNPs) were used to assess finescale genetic structure, diversity, relatedness, population connectivity and local adaptation at both broad (biogeographic region) and local (within-biogeographic region) scales. An independent hydrodynamic particle dispersal model was also used to assess population connectivity. The overall pattern of population differentiation at the country level for H. scabra in the Philippines is complex, with nine genetic stocks and respective management units delineated across 5 biogeographic regions: (1) Celebes Sea, (2) North and (3) South Philippine Seas, (4) South China and Internal Seas and (5) Sulu Sea. Genetic connectivity is highest within proximate marine biogeographic regions (mean Fst=0.016), with greater separation evident between geographically distant sites (Fst range=0.041-0.045). Signatures of local adaptation were detected among six biogeographic regions, with genetic bottlenecks at 5 sites, particularly within historically heavilyexploited locations in the western and central Philippines. Genetic structure is influenced by geographic distance, larval dispersal capacity, species-specific larval development and settlement attributes, variable ocean current-mediated gene flow, source and sink location geography and habitat heterogeneity across the archipelago. Data reported here will inform accurate and sustainable fishery regulation, conservation of genetic diversity, direct broodstock sourcing for mariculture and guide restocking interventions across the Philippines. [ABSTRACT FROM AUTHOR]

Under the double pressures of economic growth and ecological environment protection, sea green transformation and the sustainable development of mariculture are critical. This paper constructs an evolutionary game model with the government as the main body and mariculture farmers (enterprises) as the main body and puts forward the research hypothesis. Based on 2006–2019 longitudinal data of nine provinces along China's coast, using multi-period Difference-in-Difference (DID) and dual robust estimation, we empirically investigate the national oceanic ranch demonstration zones for the influence of the green sea aquaculture and their mechanism of action. The results showed that (1) the efficiency of green level of mariculture industry in China is not high, and the establishment of national marine pasture demonstration zone has not effectively promoted the improvement of green level of mariculture industry; (2) the institutional environment, unreasonable industrial structure, and lack of scientific and technological innovation have an effect on the national oceanic ranch demonstration area as the main causes of failure to effectively promote marine green farming; (3) the establishment of the national multi-period demonstration area in the north significantly hindered the growth of the green level of mariculture and fell into the "policy trap", while the establishment of the national multi-period demonstration area in the south significantly promoted the growth of the green level of mariculture. The conclusions of this paper provide an empirical basis and reference for the improvement of the national marine pasture demonstration zone policy and the green transformation of mariculture to a certain extent. [ABSTRACT FROM AUTHOR]

This study provides a comprehensive analysis of the financial performance of aquaculture firms in Portugal from 2013 to 2022, considering regional, age, and size dynamics. Using financial data from the ORBIS database, key performance indicators are calculated to assess the industry's economic sustainability, regional disparities, and firm-level effects. The analysis reveals insights into the resilience of aquaculture firms in navigating economic challenges, such as the COVID-19 pandemic, and highlights the importance of tailored policy interventions to support regional development and industry competitiveness. Age trends show the influence of industry experience on financial performance, with older firms demonstrating higher turnover and profitability. Size trends indicate the advantages of economies of scale for larger firms, while smaller firms exhibit agility and innovation. This study contributes to the understanding of aquaculture economics in Portugal, providing valuable implications for policymakers, industry stakeholders, and aquaculture firms. By considering regional, age, and size dynamics, stakeholders can develop comprehensive strategies to enhance the sector's long-term sustainability and resilience in an increasingly dynamic market environment. Recommendations are provided for policymakers to support regions with lower performance metrics, enhance infrastructure development, and promote workforce productivity to foster balanced economic growth across the aquaculture sector in Portugal. [ABSTRACT FROM AUTHOR]

Development of environment-friendly and efficient aquaculture effluent treatment system is crucial for sustainable intensification of aquaculture, in the face of the rapidly increasing environmental pressure in the mariculture industry. In this study, mariculture wastewater was treated by the anoxic-anaerobic-oxic biochemical treatment system (A2O system) with traditional activated sludge replaced by nitrifying bacteria, denitrification bacteria and phosphorus accumulating bacteria absorbed on PBS carrier biofilms suitable for saline/brackish water. The results showed that biofilm-enhanced A2O system can effectively remove pollutants from aquaculture wastewater. The removal efficiencies of CODMn, NH4 +-N, TN and TP in A2O system were approximately 86.3%-90.8%, 97.7%-99.5%, 94.6%-95.2% and 97.0%-98.1%. The results further showed that CODMn, NH4 +-N, and TN were mainly removed in anaerobic tank and anoxic tank, while TP was mainly removed in the anoxic tank and oxic tank. The biofilm-enhanced A2O system by adding nitrifying bacteria and phosphorus accumulating bacteria biofilms using PBS as carriers instead of conventional activated sludge could be applied to the treatment of circulating aquaculture wastewater. This study provides a feasible scheme for enhancing the efficiency of A2O system in the treatment of aquaculture tail water, and provides a reference for the immobilization of microorganisms. [ABSTRACT FROM AUTHOR]

This research article describes Chile's climate change adaptation policies and plans for marine aquaculture in Chile, with a focus on the nationally important salmon farming industry, and assesses whether they have adequately addressed legal barriers to adaptation and the need for legal transformation. The article first outlines Chile's climate change law, policies, and institutional framework, as reflected in the 2022 Framework Act on Climate Change, the 2020 updated Nationally Determined Contribution, the 2022 Strengthening of the Nationally Determined Contribution, and the 2022 Long-Term Climate Strategy. The article highlights the special attention given to the ocean-climate nexus in both international and national policy agendas. It then summarizes and assesses the adaptation policies and plans for the aquaculture sector. Three main shortcomings are identified: the lack of implementation of committed activities, the lack of a strategic vision for the role of aquaculture in a changing climate and oceans, and the lack of attention to the limits of adaptation resulting from existing regulatory frameworks. The article then strengthens this assessment with a legal analysis of the adaptive capacity of aquaculture planning and leasing frameworks. This assessment concludes that mainstreaming climate change into existing planning instruments is an ineffective adaptation measure due to the fragmented, rigid, and inefficient legal framework for the planning of aquaculture and other uses of the coastal zone. In turn, the leasing system is too rigid to allow for effective adaptation. Various mechanisms to introduce flexibility are suggested. The article concludes by highlighting an unprecedented window of opportunity to advance strategic, coherent, long-term, and transformative adaptation, resulting from concurrent initiatives to reform or update aquaculture law, policy, and adaptation planning and the principled approach to climate action embedded in the Framework Act on Climate Change. [ABSTRACT FROM AUTHOR]

Denitrification and anaerobic ammonium oxidation (anammox) are key processes for nitrogen removal in aquaculture, reducing the accumulated nitrogen nutrients to nitrogen gas or nitrous oxide gas. Complete removal of nitrogen from aquaculture systems is an important measure to solve environmental pollution. In order to evaluate the nitrogen removal potential of marine aquaculture ponds, this study investigated the denitrification and anammox rates, the flux of nitrous oxide (N2O) at the water–air interface, the sediment microbial community structure, and the gene expression associated with the nitrogen removal process in integrated multi-trophic aquaculture (IMTA) ponds (Apostistius japonicus-Penaeus japonicus-Ulva) with different culture periods. The results showed that the denitrification and anammox rates in sediments increased with the increase of cultivation periods and depth, and there was no significant difference in nitrous oxide gas flux at the water–air interface between different cultivation periods (p > 0.05). At the genus and phylum levels, the abundance of microorganisms related to nitrogen removal reactions in sediments changed significantly with the increase of cultivation period and depth, and was most significantly affected by the concentration of particulate organic nitrogen (PON) in sediments. The expression of denitrification gene (narG, nirS, nosZ) in surface sediments was significantly higher than that in deep sediments (p < 0.05), and was negatively correlated with denitrification rate. All samples had a certain anammox capacity, but no known anammox bacteria were found in the microbial diversity detection, and the expression of gene (hzsB) related to the anammox process was extremely low, which may indicate the existence of an unknown anammox bacterium. The data of this study showed that the IMTA culture pond had a certain potential for nitrogen removal, and whether it could make a contribution to reducing the pollution of culture wastewater still needed additional practice and evaluation, and also provided a theoretical basis for the nitrogen removal research of coastal mariculture ponds. [ABSTRACT FROM AUTHOR]