Search Results (153)

Coral reefs are increasingly impacted by marine heatwaves and global warming, with the 2023–2024 El Niño–Southern Oscillation (ENSO) event causing unprecedented thermal stress across the Eastern Tropical Pacific. This study assessed the effects of this event on coral reefs in the Gulf of Papagayo, Costa Rica. Sea surface temperatures exceeded the bleaching threshold for seven months, reaching a record 10.2 Degree Heating Weeks—twice the levels recorded during the 1997–1998 ENSO. Benthic and fish community surveys revealed severe coral mortality, particularly in Pocillopora-dominated reefs, with some sites losing over 90% of live coral cover. Resilience varied across sites, likely influenced by factors such as local water circulation, coral genetic diversity, symbiont type, and heterotrophic capacity. Reefs with higher genetic diversity and thermally tolerant Durusdinium symbionts showed partial recovery. Seasonal upwelling appeared to buffer thermal stress in some areas, potentially acting as a natural climate refuge. Bleaching also impacted reef fish communities, with a notable decline in invertebrate-feeding species on degraded reefs. These findings highlight the interplay between prolonged thermal stress, coral biology, and local oceanographic processes in shaping reef resilience. Identifying and protecting such climate refugia will be critical for coral conservation under future climate change scenarios. Full article

The Mediterranean Diet (MD) is globally recognized not only for its well-established benefits to human health but also for its potential as a sustainable dietary model from environmental perspectives. Primarily based on plant-based foods, olive oil, fish, and seasonal and local products, the MD stands out for its ability to reduce overall mortality and the incidence of chronic diseases. At the same time, it is a low environmental impact dietary approach, contributing to the reduction in greenhouse gas emissions, water savings, biodiversity conservation, and soil regeneration. This narrative review was conducted by searching the Scopus and PubMed databases, covering all publications up to 2011, applying predefined inclusion and exclusion criteria, and ultimately including 33 studies. The paper provides a synthesis of the key elements that make the MD a paradigm of sustainability, analyzing critical indicators such as carbon, water, and energy footprints, land use, food waste generation, and carbon sequestration. It also addresses the decline in adherence to the MD, even in Mediterranean countries, highlighting the socio-economic, cultural, and behavioral causes, as well as the necessary strategies to promote its rediscovery and adaptation to contemporary contexts. Full article

Aquaculture plays a vital role in meeting the global demand for high-quality protein. However, the fish industry is challenged by infectious diseases, including gill conditions such as epitheliocystis. Epitheliocystis is characterized by cyst-like epithelial lesions, which occur in the gills of fish, and is associated with intracellular bacteria including Chlamydia-related bacteria. Although epitheliocystis was initially regarded as of low significance, attention is increasing due to its impact on commercially important fish species in intense farming conditions. This review evaluates the roles of aquatic chlamydiae as pathogens contributing to fish morbidity and mortality, and as members of fish microbiota. Additionally, Chlamydia-related bacteria are thought to be involved in complex gill disease (CGD), characterized by lamellar fusion, epithelial hyperplasia, and inflammation. Recent discoveries have expanded the diversity of Chlamydiota isolated from fish, with novel species such as Candidatus (Ca.) Panilichlamydia rohitae, Ca. Piscichlamydia trichopodus, and Chlamydia vaughanii identified in different fish hosts. Most causative agents of epitheliocystis have not yet been cultured in vitro, although C. vaughanii, the first Chlamydiaceae member isolated from fish, was successfully cultured. As C. vaughanii was recently shown to be able to propagate in mammalian cells, it raises concerns about its zoonotic potential, although a pathogenic role has yet to be described. Full article

Aeromonas hydrophila is an important zoonotic bacterium that is related to multiple diseases in humans, terrestrial animals, and aquatic animals. Bacterial septicemia caused by A. hydrophila often results in high mortality and severe economic losses. Antibiotics, the major approach to dealing with bacterial infections, are limited due to the occurrence of antibiotic resistance. Anti-virulence strategies provide a promising approach to combat resistant bacterial infections. Here, growth curves, hemolysis, biofilm formation, and animal studies were performed to investigate the effect of fisetin against A. hydrophila. Moreover, RNA-seq technology was employed to determine the potent mechanism of fisetin. The results showed that fisetin could dose-dependently reduce the hemolytic activities mediated by aerolysin and hinder biofilm formation. Animal studies showed that treatment with 50 mg/kg fisetin could remarkably reduce the mortality to 40% in the infected group compared with fish in the fisetin-free group. Further, transcriptome analysis demonstrated that there were 565 differentially expressed genes (DEGs) after treatment with 16 μg/mL fisetin. Fisetin significantly impacted the pathways related to oxidative phosphorylation, the citrate cycle, and virulence factor regulation. Furthermore, 159 virulence-related genes were influenced after fisetin treatment. Collectively, these findings revealed that fisetin could mitigate the pathogenicity of A. hydrophila by affecting oxidative phosphorylation and the citrate cycle pathway as well as inhibiting the production of virulence factors. The study not only identified a powerful substance for managing A. hydrophila-associated diseases in aquaculture but also clarified the mechanism of plant medicines in controlling diseases caused by bacterial pathogens. Full article

Background: Vaccination is often a highly effective approach for protecting against clinical disease and mortality caused by viruses. However, vaccine efficacy against viral transmission has rarely been assessed, which can provide vital information on the eradication efficacy and sustainability of vaccines in the field. Methods: Here, we evaluated the host mortality, shedding, and direct fish-to-fish transmission protection efficacy of three vaccine regimens (DNA, inactivated, and attenuated) against infectious hematopoietic necrosis virus (IHNV) in rainbow trout. We quantified protection against single- and mixed-genotype IHNV infections when the vaccines were delivered by intramuscular injection, intraperitoneal injection, and bath immersion, respectively, to reflect field conditions. Results: All three vaccine regimens provided significant protection against fish mortality. The DNA vaccine regimen was qualitatively the most protective and the attenuated vaccine regimen the least. However, these three vaccines provided limited protection against viral shedding. Cumulative shedding over the course of the infection was only slightly reduced compared to unvaccinated fish. There was some indication that the viral genotype fish were exposed to influenced vaccine efficacy, perhaps as a result of genetic similarity to the vaccine strain. Likewise, the DNA vaccine reduced direct transmission in fish cohabitation experiments from 100% to 50%. The inactivated and attenuated vaccine had little impact on IHNV transmission. Conclusions: Collectively, our results suggest that existing IHNV vaccines that increase host survival provide minimal virus transmission protection in rainbow trout, which is likely to limit their long-term efficacy in the field. This work contributes to a growing body of evidence that enhancement of the transmission protection of IHNV and other vaccines will likely bolster disease reduction in the field. Full article

The ten-year fishing ban on the Yangtze River aims to restore aquatic biodiversity and rebuild fishery resources. Megalobrama skolkovii, a key species in the basin, was investigated using 2024 data to provide a preliminary assessment of its population structure, stock dynamics, and early recovery. Age analysis (n = 243) showed that 1–6-year-olds were dominated by fish aged 3 (35%), with few older than 4, indicating moderate structural truncation. Growth parameters modeled by the von Bertalanffy Growth Function yielded L_∞ = 61.89 cm and k = 0.25 year⁻¹, with a weight–growth inflection age of 4.4 years. Natural mortality (M = 0.48 year⁻¹) was estimated using Pauly’s empirical formula, and total mortality (Z = 0.55 year⁻¹) was estimated from the catch curve analysis. While fishing mortality (F) was statistically indistinguishable from zero, a plausible low-intensity fishing scenario was explored to assess potential impacts of residual activities. Length-based indicators (LBIs) showed P_mat = 46.05%, P_opt = 9.51%, and P_mega = 6.88%, suggesting reproductive recovery but incomplete structural restoration. These preliminary findings reveal an asymmetrical recovery trajectory, whereby physiological improvements and enhanced recruitment have occurred, yet full structural restoration remains incomplete. This underscores the need for continued, long-term conservation and monitoring to support population resilience. Full article

This research examined the impact of dietary supplementation with Phlogacanthus pulcherrimus extract (PPE) on the growth, disease resistance, and expression of immune-, growth-, and antioxidant-related genes in Labeo chrysophekadion. Over 150 days, 90 fish from each group were fed diets with 0 (control), 0.25, 0.50, or 0.75 g/kg of PPE. Phytochemical analysis revealed phenolics (96.00 mg GAE/g), flavonoids (17.55 mg QE/g), anthraquinones, and triterpenoids, along with moderate antioxidant activity (IC₅₀ = 1314.08 μg/mL). One-way ANOVA of growth indices, including weight gain, specific growth rate, feed conversion ratio, and survival rate, revealed no significant differences (p > 0.05); however, PPE supplementation significantly enhanced immune and antioxidant gene expression. IL-1β was significantly (p < 0.05) upregulated at all doses, with the highest expression observed at 0.50 g/kg, showing a fivefold increase compared to the control. In addition, the highest relative expressions of IGF-1 and CAT were found at 0.75 g/kg, with 4.5-fold and 3.5-fold increases compared to the control, respectively. PPE at 0.75 g/kg decreased the cumulative mortality rate (CMR) by 20% compared to the control group, which had a CMR of 50% following exposure to Aeromonas hydrophila. PPE acted as an effective immunostimulant and antioxidant, supporting reduced antibiotic reliance in aquaculture. Full article

This research investigated the temporal dynamics of the anthropogenic impact of fishing pressure on the resilience of the fish species Sarotherodon melanotheron (Rüppel, 1858) in the African Lake Toho, located in southwest Benin. The sampling and analysis of monthly length frequency data were conducted from April 2002 to March 2003 and from April 2022 to March 2023 using the FAO-ICLARM Stock Assessment Tool (FiSAT II software program (version 1.2.2.). The analysis of the S. melanotheron population in Lake Toho revealed a significantly diminishing resilience potential, reflected mainly in general reductions in both the average size and weight of individuals. There was a notable reduction in the size of Sarotherodon melanotheron individuals caught between 2002–2003 and 2022–2023, reflecting the increased pressure on juvenile size classes. Catches are now concentrated mainly on immature fish, revealing increasing exploitation before sexual maturity is reached. An analysis of maturity stages showed a decrease in the percentage of mature individuals in the catches (69.27% in 2002–2003 compared to 55.07% in 2022–2023) and a reduction in the number of mega-spawners (4.53% in 2002–2003 compared to 1.56% in 2022–2023). Growth parameters revealed a decrease in asymptotic length (from 32.2 cm to 23.8 cm) and longevity (from 9.37 years to 7.89 years), while the growth coefficient slightly increased. The mean size at first capture and optimal size significantly declined, indicating increased juvenile exploitation. The total and natural mortalities increased, whereas the fishing mortality remained stable. The exploitation rate remained high, despite a slight decrease from 0.69 to 0.65. Finally, the declines in the yield per recruit, maximum sustainable yield, and biomass confirm the increasing fishing pressure, leading to growth overfishing, recruitment overfishing, reproductive overfishing, and, last but not least, a decreasing resilience potential. These findings highlight the growing overexploitation of S. melanotheron in Lake Toho, compromising stock renewal, fish population resilience, sustainability, and production while jeopardizing local food safety. Full article

Fish kills are sudden mass mortalities that occur in freshwater and marine systems worldwide. Fish kill surveys are essential for assessing the ecological and economic impacts of fish kill events, but are often labor-intensive, time-consuming, and spatially limited. This study aims to address these challenges by exploring the application of unoccupied aerial systems (or drones) and deep learning techniques for coastal fish carcass detection. Seven flights were conducted using a DJI Phantom 4 RGB quadcopter to monitor three sites with different substrates (i.e., sand, rock, shored Sargassum). Orthomosaics generated from drone imagery were useful for detecting carcasses washed ashore, but not floating or submerged carcasses. Single shot multibox detection (SSD) with a ResNet50-based model demonstrated high detection accuracy, with a mean average precision (mAP) of 0.77 and a mean average recall (mAR) of 0.81. The model had slightly higher average precision (AP) when detecting large objects (>42.24 cm long, AP = 0.90) compared to small objects (≤14.08 cm long, AP = 0.77) because smaller objects are harder to recognize and require more contextual reasoning. The results suggest a strong potential future application of these tools for rapid fish kill response and automatic enumeration and characterization of fish carcasses. Full article

Background: Sleep is a fundamental component of health, and deprivation has been linked to numerous adverse outcomes, including reduced academic and occupational performance, greater risk of accidents, and increased susceptibility to chronic diseases and premature mortality. Dietary and lifestyle behaviors are increasingly recognized as key determinants of sleep quality. Women are particularly susceptible to sleep disturbances due to hormonal fluctuations and psychosocial factors. However, women remain underrepresented in sleep research. This study aims to examine the associations between sleep quality, nutrition, and lifestyle in a large cohort of Spanish women. Methods: A cross-sectional study was conducted with 785 women aged 18–64. Participants completed the Pittsburgh Sleep Quality Index (PSQI) and the NutSo-HH questionnaire on dietary and lifestyle behaviors. Descriptive analyses, correlation matrices, Gaussian Graphical Models, and Principal Component Analyses were used to assess relationships between variables. Results: More than half of the participants rated their sleep quality as good or very good, although over 30% experienced frequent nighttime awakenings. Poor sleep quality was significantly associated with higher alcohol consumption, lower vegetable and white fish intake, and lower levels of physical activity. Diets rich in ultra-processed foods correlated moderately with subjective poor sleep and daytime dysfunction. However, no strong associations were found between stimulant consumption, late meals, or dietary patterns (e.g., Mediterranean diet) and sleep. Self-perceived health emerged as a protective factor, while nocturnal lifestyles were linked to longer sleep latency and fragmented sleep. Conclusions: In adult women, better sleep quality is linked to healthy dietary choices, regular physical activity, and a positive perception of general health. In contrast, alcohol use and irregular lifestyles are associated with poor sleep. Individual variability and cultural adaptation may moderate the impact of some traditionally harmful behaviors. Personalized, multidimensional interventions are recommended for promoting sleep health in women. Full article

Fishery bycatch is a significant threat to biodiversity, with birds being frequent casualties. Current research mainly focuses on seabird bycatch in large-scale marine fisheries, while bird bycatch in inland freshwater areas remains poorly understood. Crayfish traps are extensively used in China’s freshwater environments, but their ecological impacts on birds are overlooked due to monitoring difficulties. Through iEcology approaches, we collected and analyzed 146 bird bycatch incidents in crayfish traps from Chinese social media platforms between September 2010 and December 2023. The results revealed 420 identified birds from 62 species (11 orders, 24 families), predominantly omnivorous and carnivorous, while 106 individuals could not be identified. Cases were concentrated in the middle and lower reaches of the Yangtze River, showing significant positive correlations with water area ratio and aquaculture production (p < 0.001). During fishing seasons, the number of cases, species, and individuals were significantly higher (p < 0.001), though mortality rates increased in off seasons. The middle and lower reaches of the Yangtze River are main production areas of red swamp crayfish (Procambarus clarkii) and Chinese mitten crab (Eriocheir sinensis), where intensive use of crayfish traps may increase bird bycatch risk. Despite existing regulations, systematic supervision is needed to minimize ecosystem impacts. Full article

To ensure sustainability, the Ecosystem Approach to Fisheries (EAF) requires the evaluation of the impacts of fisheries beyond the main targeted species, to include those on bycaught, endangered, threatened and protected populations and keystone species. However, traditional stock assessments require extensive datasets that are often unavailable for data-limited fisheries, particularly in small-scale settings or in the Global South. This study evaluates the robustness of length-based approaches for fish stock assessment by comparing simple indicators and quantitative methods using an age-structured Operating Model. Simulations were conducted for a range of scenarios, for a range of life-history types and recruitment and natural mortality dynamics. Results reveal that while length-based approaches can effectively track trends in fishing mortality, performance varies significantly depending on species-specific life histories and assumptions about key parameters. Simple indicators often matched or outperformed complex methods, particularly when assumptions about equilibrium conditions or natural mortality were violated. The study highlights the limitations of length-based methods for classifying stock status relative to reference points, but demonstrates their utility when used with historical reference periods or as part of empirical harvest control rules. The findings provide practical guidance for applying length-based approaches in data-limited fisheries management, ensuring sustainability in data- and capacity-limited situations. Full article

Climate change-induced heavy rainfall during summer months can further increase suspended solid loads in rivers, elevating turbidity. Such elevated turbidity can compromise fish gill tissue integrity and impair oxygen uptake, potentially leading to fatal impacts in aquatic ecosystems. Therefore, this study aims to examine fish migratory behaviors and physiological responses to varying turbidity levels through experimental trials to generate baseline data for assessing fish habitat suitability. The experimental design comprised two primary components: an investigation of turbidity avoidance behaviors and an analysis of habitat compatibility through extended exposure to turbid conditions. This study focused on dominant freshwater fish species native to South Korea, Zacco platypus, Pseudopungtungia nigra, and Zacco koreanus. Fish condition in response to turbidity was monitored over a 15-day period, during which locomotor activity and water quality parameters were recorded. In the control group tank with no turbidity, all species exhibited unrestricted swimming patterns without depth preference. However, in moderate and high turbidity treatments, all demonstrated preferential utilization of middle- and lower-depth strata. In addition, the highest number of fish mortality occurred in high-turbidity zones because of respiratory impediments from elevated suspended solid concentrations. These findings provide valuable insights into fish mobility and habitat utilization patterns in rivers experiencing sudden turbidity events, such as those associated with weir operations. Full article

Background/objectives: Schistosomiasis is a parasitic disease that represents a serious public health problem. An alternative for the control of snails, intermediate hosts of schistosomiasis, is the use of molluskicides. Niclosamide, recommended by the WHO, has limitations, such as environmental toxicity, which has driven the search for safer and biodegradable alternatives, especially of plant origin. In this context, this study investigated the biological activity of Cymbopogon winterianus essential oil on embryos, juveniles, and adults of Biomphalaria glabrata and cercariae of Schistosoma mansoni. Methods: Essential oils (EOs) were extracted from fresh leaves via the Clevenger system and characterized via gas chromatography (GC/MS and GC/FID), revealing geraniol (25.0%), citronellal (29.2%), citronellol (10.5%) and elemol (9.6%) as the main components. Results: The results revealed lethal concentrations 90 (LC₉₀) for young and adult snails of 60.72 mg/L, 74.21 mg/L and 115.35 mg/L, respectively. In the histological analysis, no changes were observed in the tissues of the mollusks exposed to the lethal concentration 25 (LC₂₅). However, the lethal concentrations 50 (LC₅₀) and 75 (LC₇₅) caused crystalline concretions in proximity to the renal saccular portion. At a concentration of 60 mg/L, the oil resulted in 100% lethality in embryos and cercaricidal activity greater than 90% in 3 h. Acute toxicity tests in mice via the intraperitoneal or oral route did not reveal toxic effects, with hematological and biochemical parameters within the reference values. Furthermore, the oil did not inhibit acetylcholinesterase (AChE), indicating low toxicity to fish, and caused a slight reduction in human butyrylcholinesterase (hBChE) activity without affecting human AChE, which suggests low toxicity to mammalian tissues. In terms of environmental impact, the oil was not toxic to algae until the 75th day, with mortality observed thereafter. Conclusions: These results indicate that essential oils have great potential as biodegradable and safe alternatives for controlling mollusks and interrupting the schistosomiasis cycle. Full article

Aquaculture is the fastest-growing food production sector. However, it faces significant challenges, including demand from a growing global population, which is estimated to reach 10.4 billion by the year 2100, disease outbreaks, environmental impacts, and the overuse of antibiotics. To address these issues, sustainable alternatives such as the use of microorganisms (probiotics, bacteriophages, and genetically modified microorganisms) have gained attention. This review examines the effects of these microorganisms on fish aquaculture, focusing on their potential to improve growth, health, and disease resistance while reducing environmental impacts. Probiotics, particularly lactic acid bacteria and yeasts, have been shown to enhance immune responses, digestive enzyme activity, and nutrient absorption in fish. Bacteriophages offer a promising alternative to antibiotics for controlling bacterial pathogens, with studies demonstrating their efficacy in reducing mortality rates in infected fish. Additionally, genetically modified microorganisms (GMMs) have been explored for their ability to produce beneficial compounds, such as enzymes and antimicrobial peptides, which can improve fish health and reduce the need for chemical treatments. Despite their potential, challenges such as regulatory hurdles, public acceptance, and environmental risks must be addressed. This review highlights the importance of further research to optimize the use of microorganisms in aquaculture and underscores their role in promoting sustainable practices. By integrating these biological tools, the aquaculture industry can move towards a more sustainable and environmentally friendly future. Full article