Search Results (304)

Nowadays, microplastic (MP) pollution has attracted increasing interest from the scientific community. This systematic review investigated the MP concentration in various tissues of five commercial fish species (Engraulis encrasicolus, Boops boops, Sardina pilchardus, Sardinella aurita, and Trachurus mediterraneus) in different Mediterranean water bodies in order to identify spatial trends and key analytes influencing their variation. The reported concentrations of MPs in all fish ranged from 4.2 particles/individual in the southeastern Mediterranean to 1.2 particles/individual in the western part, but these values are highly uncertain due to inconsistent methodologies, absence of recovery tests, and incomplete data reporting. No significant difference was found in the MP concentration of the different tissues of these species. The key factor affecting the MP concentration was the water body from which they were collected. This systematic review suggests that fewer than six samples may not provide statistically reliable results, and that a lack of detailed data reporting, despite the advances in chemical characterization techniques, continues to limit the robustness of MP studies. Additionally, this study evaluated how methodological differences could influence the reported MP concentrations. These findings offer a comprehensive overview of the MP expansion in the Mediterranean waterbodies and fish species, and provide recommendations for future research design improvement. Full article

In order to minimize problems associated with the operation of surface water intakes, passive wedge-wire screens are increasingly being used. Deflectors of special design are placed inside the intake heads to reduce local maximum inlet velocities and to ensure a uniform velocity distribution over their surface. The use of computer software based on Computational Fluid Dynamics (CFD) methods enabled simulations and optimization of the intake head design. Subsequently, a series of laboratory tests was conducted. Several scenarios were considered, varying the flow rates in the hydraulic flume and taking into account both the presence and absence of the deflector. Velocities around the intake head were measured, and the amount of particles in the water attracted to the head surface under the analyzed conditions was assessed. The results confirm the clear effect of the deflector on the velocity distribution. Its use originates reduced velocities near the head surface, as well as a smaller amount of debris deposited on the screen, while maintaining efficiency. At the same time, lower inlet velocities close to the head surface reduce the risk of entrainment and potential injury or mortality of young fish, fry, and eggs. Full article

The recycling of by-products from fish processing procedures has recently been attracting increased attention. In this study, three types of gelatin were isolated from grass carp skin, bone, and scales, named SKG, BG, and SCG, respectively, and their structural and functional characteristics were investigated. Compared with BG and SCG, SKG exhibited the highest extraction yield (18.30 ± 0.24%) and protein content (90.12 ± 0.21%) and the lowest ash content (1.50 ± 0.08%). Electrophoresis analysis revealed that SKG contained more α chains than BG and SCG. Fourier transform infrared spectra showed that the absorption peaks of gelatin were mainly positioned in amide band regions, whereas some of the triple helix structure was lost. More than 85% solubility was observed in all gelatin types with pH 3–10. Meanwhile, there was a higher gel strength in SKG (288.2 g) than in BG (270.2 g) and SCG (245.1 g). Furthermore, the water or oil absorption and emulsifying characteristics of SKG were also better than those of BG and SCG. The differences in functional properties between gelatin types appear to be related to protein distribution and composition. All the results indicate that grass carp skin is a material with the potential to extract gelatin with a higher yield and gel strength and better functional characteristics compared with bone and scales. Full article

The Neptunea cumingii (N. cumingii) fishing industry has long relied on expensive and perishable skate (Raja porosa) meat as bait. The unknown chemical attraction mechanism has hindered the development of artificial alternatives. This study employed untargeted metabolomics to analyze the chemical composition of skate meat and combined quantitative behavioral analysis to identify four key attractant compounds. These compounds were taurine, glutamate (Glu), inositol, and lactate. A standardized behavioral assessment system was established using the three parameters of response time, displacement distance, and movement velocity. This system enabled precise quantification of attraction efficacy. Concentration-gradient experiments determined the optimal concentration for all four compounds as 0.1 M. Taurine exhibited the strongest single-compound activity. It reduced response time by 50% and increased displacement distance by 164.5%. The mixture of four compounds at 0.1 M produced significant synergistic effects. The mixture achieved a comprehensive score of 93.6. This score approached that of natural skate meat at 94.8. All behavioral parameters improved by over 69% compared to the best single compound. These findings reveal the key attractant components in skate meat. They provide a scientific basis for developing efficient and stable artificial attractants. This research holds substantial value for promoting sustainable development of the N. cumingii fishing industry. Full article

Astaxanthin has attracted considerable interest, owing to its potent antioxidant and pigmentation properties. To investigate its effects of astaxanthin on body color variation in Lutjanus erythropterus, fish were divided into a control group and a treatment group fed an astaxanthin-supplemented diet. Body color parameters, growth performance, and liver antioxidant enzyme activities were measured at the end of the experiment. Tissues, including skin, intestine, liver, and blood, were subsequently collected for transcriptome sequencing. The results demonstrate that the astaxanthin-treatment group exhibited significantly enhanced body coloration alongside improved body length, body weight, and specific growth rate compared to the control group (p < 0.05). Specifically regarding the red–green value (a*), the treatment group showed significantly higher values on the ventral skin, dorsal skin, and gill cover (p < 0.05). The yellow–blue (b*) and lightness (L*) values were also significantly elevated in the ventral skin and gill cover (p < 0.05), although no significant differences were observed in the dorsal skin (p > 0.05). The skin was identified as the tissue with the highest total carotenoid content. Astaxanthin supplementation enhanced liver antioxidant capacity, evidenced by significantly elevated total superoxide dismutase (T-SOD) activity and significantly reduced malondialdehyde (MDA) levels in the treatment group (p < 0.05). Catalase (CAT) activity did not differ significantly between groups (p > 0.05). Transcriptomic analysis identified several coloration-associated genes, such as bco1, bco2, gstt1, and gstz1. It also revealed significant enrichment in key metabolic pathways (fatty acid, cholesterol, and retinol metabolism) and signaling pathways (PPAR and PI3K-Akt). Furthermore, the expression of multiple solute-carrier family members and apolipoproteins was detected, with notable enrichment in lipid digestion and absorption, cholesterol metabolism, and several key immune-related signaling pathways. These findings provide a theoretical basis for understanding the molecular mechanisms of carotenoid-mediated pigmentation in L. erythropterus. Full article

The estuaries of the Mississippi River Delta are among the most productive coastal ecosystems in the world and have attracted human fishing communities for centuries. Beginning in the early 20th century, the oil and gas industry also emerged as a powerful economic force in exploiting coastal fossil fuel deposits. This paper reviews the complex history of the oil and gas industry in Southeast Louisiana, including its relationships with political corruption, inequality, pollution, and environmental catastrophe; and also its role in supporting coastal fishing communities with complementary economic opportunities. In the 21st century, a series of disasters—above all Hurricane Katrina in 2005 and the B.P. oil spill in 2010—drew attention to the risks inherent to the region, as well as its crucial role in buffering the impacts of tropical storms for inland urban communities. This paper examines the evolution of fisheries regulations and their consequences of small-scale fishers, focusing especially on the banning of gill net use in 1990s. By combining historical information with ethnographic interviews and participant observation, this paper examines the complex political–economic forces involved in shifting regulatory frameworks and policies, and it shows their negative consequences for fishing communities facing an existentially threatening combination of coastal erosion, fisheries declines, and various macroeconomic headwinds. This paper argues that resilient coastal communities are crucial to combating the environmental problems facing coastal regions and that rethinking fisheries regulations may be a dynamic tool in enhancing community resilience. Full article

Carbon quantum dots (CQDs) are photoluminescent nanomaterials (<10 nm) with excellent hydrophilicity, biocompatibility, and low cytotoxicity, making them attractive for biological applications. However, their use in aquaculture nutrition has remained largely unexplored. This study investigated the effects of dietary CQDs on zebrafish (Danio rerio), a model organism with approximately 70% genetic homology with humans. CQDs were synthesized hydrothermally from unripe Citrus limon and characterized by UV–visible (UV-Vis) spectroscopy, UV–vis transillumination, scanning electron microscopy (SEM), transmission electron microscopy (TEM), energy-dispersive X-ray analysis (EDX), Fourier-transform infrared spectroscopy (FT-IR), and photoluminescence (PL) spectroscopy. Zebrafish were fed diets containing varying CQD concentrations, and growth performance, condition factor (K), hematological parameters, enzymatic activity, and tissue morphology were assessed. Feeds supplemented with 2 mL CQDs produced significant improvements in growth and biochemical indicators without adverse effects. Hematological and enzymatic profiles remained within normal ranges, and histological examination revealed no morphological abnormalities, indicating the absence of toxicity. These findings suggest that citrus-derived CQDs can enhance zebrafish growth and maintain physiological health, thereby supporting their potential as safe functional feed additives in aquaculture. This approach may open new opportunities for the application of CQDs in sustainable fish farming and the broader food industry. Full article

The COVID-19 pandemic has severely affected Thailand’s economy, forcing many workers to return to their hometowns and engage in agricultural activities. Community-Based Tourism (CBT) has become a significant strategy to mitigate these effects by leveraging local cultural resources. This study aims to (1) assess the potential of cultural resources for tourism development in Koh Perd fishing village, Chanthaburi, Thailand, and (2) examine the determinants of revisit intentions among Thai tourists. To address the first objective, qualitative research was conducted through in-depth interviews with 15 Thai tourists, analyzed using coding analysis, while a quantitative survey of 400 respondents assessed the perceptions of cultural resources. The findings indicate that the village’s historic houses (Ruen Ran Kha) are perceived as the most valuable tourism assets, followed by cultural authenticity and aesthetics, respectively. For the second objective, data from 400 Thai tourists were analyzed using Exploratory Factor Analysis (EFA), Confirmatory Factor Analysis (CFA) and multiple regression. The results reveal that destination attractions, marketing and accessibility, and safety and security are significant factors influencing revisit intentions. Full article

The miniaturization of ocean parameter monitors is critical for environmental monitoring and oceanographic research. In recent years, rapid developments in data processing, artificial intelligence, micro-nano manufacturing and advanced materials have significantly improved sensing accuracy while reducing device size. The detection of key ocean parameters such as temperature, salinity, pressure, dissolved oxygen (DO), pH, nutrients, chlorophyll and so on is facilitated by these innovations. Among these emerging technologies, microfluidics and optofluidics have attracted large attention in the fields of biomedicine and environmental monitoring. These platforms have the advantages of high sensitivity, low power consumption and easy integration. Real-time and on-site monitoring can be achieved by them. Optofluidic technology shows great prospects for ocean sensing applications. Recent advances in optofluidic ocean sensors for the measurement of chemical parameters and their future potential are highlighted in this review. Ultimately, it presents the key role of optofluidic systems in realizing compact high-performance ocean parameter sensors. This plays an important role in paving the way for their integration into micro robots and the fourth generation of submersibles based on live fish. Full article

Anthropogenic barriers fragment Portuguese rivers, threatening endemic freshwater fish communities. This study compiled national inventories and peer-reviewed research (2002–2024) to quantify fishway implementation, evolution and typology, while evaluating fish performance from published research. One hundred fishways built between 1950 and 2024 were recorded, half of which were constructed after the implementation of the Water Framework Directive in Portugal (29 Dec 2005), tripling the annual construction rate. Fishways were found to be associated mainly with weirs (46%) and small hydropower plants (44%), with typology being dominated by the pool-type design (67%), nature-like facilities (18%), fish locks and combined systems (6% each), fish lifts (2%) and a single eel pass. Forty scientific contributions addressed fishway effectiveness; three-quarters dealt with pool-type facilities, while 12.5% and 10% focused on nature-like fishways and lifts, respectively. Experimental and field studies highlighted species-specific hydraulic preferences, the benefits of vertical slot and multislot configurations, and the potential of retrofitting fishways with macro-rugosities (i.e., fixed structural elements placed on the bottom) to improve non-salmonid fish passage. However, low attraction efficiency, limited multi-season monitoring and risks of aiding invasive species remain a concern. Research needs are proposed, including the refinement of species-specific hydrodynamic criteria, and the development of standardized efficiency metrics and of selective passage solutions, to advance fishway performance under Mediterranean hydrological constraints. Full article

Artificial light has been shown to enhance the fishing efficiency of fishing gear by attracting marine organisms. This study introduces a novel approach by incorporating noctilucent materials into crab pots and evaluates their effects on catch performance. Based on the crab pots commonly used on the coast, four types of crab pots were tested: ordinary crab pots (Con-pot), ordinary crab pots equipped with noctilucent sticks (Exp-pot 1), crab pots equipped with noctilucent nets (Exp-pot 2), and crab pots equipped with both noctilucent nets and sticks (Exp-pot 3). The results showed that the noctilucent material exhibits 6 h persistent emission in darkness after just 10 min of solar charging. Exp-pot 3 could significantly enhance fishing efficiency, which increased by 63.84% compared to the Con-pot. The proportion of crabs in Exp-pot 3 was the highest (86.35%), and the individual weight of crabs in Exp-pot 3 was the heaviest (61.5 g), which was 38.30% heavier than that in the Con-pot. Notably, Exp-pots 2 and 3 demonstrated superior selectivity with higher W₅₀ values (53.01 g and 54.49 g), narrower SRs (33.04–72.98 g and 32.95–76.03 g), effectively balancing target catch retention with undersized crab release, indicated that noctilucent nets exhibited stronger weight selectivity for crabs compared to noctilucent sticks. These results demonstrate that functional materials have broad potential applications in fishing gear, which could enhance the catch efficiency and individual size of crab caught. Full article

Lignin, the second most abundant biopolymer in nature after cellulose, has attracted attention for its compatibility with carbon-based materials. In this study, lignin-modified single-use pencil graphite electrodes (PGE/LG) were developed for the electrochemical detection of fish sperm DNA (fsDNA), the anticancer drug Mitomycin C (MC), and their interaction. The modified electrodes were characterized using field emission scanning electron microscopy (FE-SEM), energy-dispersive X-ray spectroscopy (EDX), cyclic voltammetry (CV), and electrochemical impedance spectroscopy (EIS) techniques. Differential pulse voltammetry (DPV) in ferri/ferrocyanide redox probe solution was employed for signal monitoring. The detection limits were calculated as 2.95 ng/mL for fsDNA between 10¹ and 10⁵ ng/mL and 0.22 pg/mL for MC between 1 and 10⁶ pg/mL. Furthermore, the interaction of DNA with MC was evaluated by DPV and EIS techniques. The cross-linking between MC and the guanine bases of DNA inhibited electron transfer, resulting in a decrease in current response and an increase in charge transfer resistance. These results demonstrate the potential of the PGE/LG platform as a cost-effective, sensitive, and rapid biosensor for DNA detection, anticancer drug analysis, and drug–DNA interaction studies. Full article

Mexico has not only successfully eliminated dog-mediated human rabies in recent years, but also the last rabies case in a dog infected with the canine variant of the rabies virus was reported in 2016. Mass dog vaccination campaigns were the cornerstone of these achievements. Unfortunately, the rabies virus still circulates in wildlife and, thus, spill-over infections in humans, livestock, and pets, including dogs, still occurs. Especially dogs that cohabit at interfaces shared with wildlife, like shepherd dogs, are at risk. These dogs are often free-roaming and difficult to restrain for vaccination purposes. Oral rabies vaccination (ORV) as an alternative vaccination strategy was tested in several rural villages in Querétaro State, Mexico. Bait acceptance and immunogenicity studies were conducted to test a licensed vaccine bait in terms of attractiveness and if the oral rabies vaccine strain, SPBN GASGAS, was able to induce an adequate immune response in local dogs, respectively. Although the egg(-flavored) bait was less well accepted (68.4%) by the dogs than the two other bait types included in the study, a bait made from boiled intestine segments (71.2%) and a bait with fish meal as an attractant (72.3%), dogs offered the egg bait were more often considered successfully vaccinated. 83.3% of the dogs offered an egg bait seroconverted during the immunogenicity study. Hence, ORV can be a suitable alternative by increasing the overall vaccination coverage of dogs that cannot be easily restrained and handled for vaccination. Full article

Artisanal fishing is a central pillar of the Angolan economy, particularly in the southern province of Namibe, where it serves as the primary economic activity for numerous coastal communities. However, these communities face significant challenges, including competition from expanding industrial fisheries and inadequate infrastructure at fishing centers, which hampers the storage, preservation, and transportation of catches. These limitations contribute to post-harvest losses and the reduced market value of products, despite the region’s rich diversity of pelagic and demersal resources. This study evaluated the economic viability of artisanal fishing in Namibe under three production scenarios, varying in catch levels and the inclusion of fish processing activities such as dried fish and fishmeal production. Scenario A (pessimistic) assumed a 10% reduction in production compared to the best estimates; Scenario B (intermediate) was based on average reported catches; and Scenario C (optimistic) considered a 10% increase in catches, accounting for seasonal and environmental variability. Results indicated that artisanal fishing was economically viable under all scenarios, with the Internal Rate of Return (IRR) consistently exceeding the Minimum Attractive Rate of Return (MARR) of 7.5%. IRR values ranged from 34.30% (Scenario A, without by-product commercialization) to 106.28% (Scenario C, with dried fish and fishmeal production and sales), representing a more than threefold increase in profitability. This substantial gain underscores the transformative potential of processing by-products into higher-value commodities, enabling integration into larger-scale and more liquid markets. Such value addition supports the concept of a proximity economy by promoting short production cycles, reducing intermediaries, and strengthening local value chains. Beyond financial returns, the findings suggest broader socioeconomic benefits, including local economic growth, job creation, and the preservation of traditional production knowledge. The payback period was less than four years in all cases, decreasing to 1.94 years in the most favorable scenario. By-products such as dried fish and fishmeal exhibit commodity-like characteristics due to their higher commercial value, increasing demand, and potential integration into regional and animal feed markets. In conclusion, diversifying marketing strategies and maximizing the use of fish resources can significantly enhance the economic sustainability of artisanal fishing, foster socioeconomic inclusion, and support the development of artisanal fishing communities in Namibe. Full article

Coral reef degradation has spurred the development of artificial structures to mitigate losses in coral cover. These structures serve as substrates for coral transplantation, with the expectation that growing corals will attract reef-associated taxa—while the substrate’s ability to directly support biodiversity is often neglected. We evaluated a novel 3D-printed modular tile made of porous terra cotta, designed with complex surface structures to enhance micro- and cryptic biodiversity, through a restoration project in Hong Kong. Over four years, we monitored 378 outplanted coral fragments using diver assessments and photography, while biodiversity changes were assessed through visual surveys and eDNA metabarcoding. Coral survivorship was high, with 88% survival after four years. Visual surveys recorded seven times more fish and almost 60% more invertebrates at the restoration site compared to a nearby unrestored area. eDNA analyses revealed a 23.5% higher eukaryote ASV richness at the restoration site than the unrestored site and 13.3% greater richness relative to a natural reference coral community. This study highlights the tiles’ dual functionality: (1) supporting coral growth and (2) enhancing cryptic biodiversity, an aspect often neglected in traditional reef restoration efforts. Our findings underscore the potential of 3D-printed ceramic structures to improve both coral restoration outcomes and broader reef ecosystem recovery. Full article