Fishes

19 pages, 3513 KiB

Open AccessFeature PaperArticle

Population Structure Dynamics of Elasmobranchs Susceptible to Shrimp Trawling Along the Southern Gulf of Mexico

by Heber Zea-de la Cruz, César Meiners-Mandujano, Javier Tovar-Ávila, Lourdes Jiménez-Badillo and Jorge Luis Oviedo-Pérez

Fishes 2025, 10(3), 91; https://doi.org/10.3390/fishes10030091 - 21 Feb 2025

Abstract

Elasmobranch species are susceptible to anthropogenic stressors such as fishing activities, particularly the bycatch in bottom-trawl fisheries. Understanding the diversity, segregation, and population structure of species at risk of capture is critical for enhancing their conservation. This study evaluated the species composition and [...] Read more.

Elasmobranch species are susceptible to anthropogenic stressors such as fishing activities, particularly the bycatch in bottom-trawl fisheries. Understanding the diversity, segregation, and population structure of species at risk of capture is critical for enhancing their conservation. This study evaluated the species composition and population structure dynamics of susceptible elasmobranch species caught as bycatch in the Mexican shrimp trawl fishery in the southern Gulf of Mexico. Data were collected by examining bycatch from 55 fishing trips conducted between 2013 and 2017 during closed and commercial fishing seasons. We analyzed the species composition, length, sex ratio, and maturity stages of susceptible species across zones, sampling seasons, and depth. Six dominant species (Rostroraja texana, Gymnura lessae, Narcine bancroftii, Pseudobatos lentiginosus, Squatina dumeril, Hypanus americanus) accounted for >98% of all captures and were found in all fishing zones, seasons, and depths. These species were caught in a range of sizes, from newborns to mature individuals, and showed both inter- and intraspecific segregation patterns across fishing zones, seasons, and depths. The elasmobranch composition and population structure in bycatch are influenced by ontogenetic segregation and bathymetric distribution of the species. Current Mexican shrimp trawl fishery regulations benefit the majority of elasmobranchs by providing comprehensive spatiotemporal protection and selective exclusion mechanisms. However, small-sized ray species and juveniles of larger species continue to face fishing pressure. The preset study highlights the southern Gulf of Mexico as an important reproductive area for demersal elasmobranchs and unravels their complex segregation behavior, leading to the identification of potential risk zones and seasons. The impacts of bycatch on the most susceptible elasmobranchs may be mitigated through improvements in trawl fishing technology and the implementation of additional temporal bans in specific trawling areas, enhancing species-specific conservation efforts. Full article

(This article belongs to the Special Issue The Roles of Fishery Biology and Fish Population Dynamics in Fisheries Management)

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17 pages, 984 KiB

Open AccessReview

Content of Short-Lived Radionuclides (⁵⁴Mn, ⁶⁰Co, and ⁶⁵Zn) in Fish

by Nataliia E. Zarubina, Vladislav Semak, Liliia P. Ponomarenko and Oleg S. Burdo

Fishes 2025, 10(3), 90; https://doi.org/10.3390/fishes10030090 - 20 Feb 2025

Abstract

This review summarizes data on the accumulation of three short-lived biogenic radionuclides—⁵⁴Mn, ⁶⁰Co, and ⁶⁵Zn—in various fish species in the cooling pond of the Chornobyl Nuclear Power Plant in Ukraine, along with an analysis of the available literature. Significant [...] Read more.

This review summarizes data on the accumulation of three short-lived biogenic radionuclides—⁵⁴Mn, ⁶⁰Co, and ⁶⁵Zn—in various fish species in the cooling pond of the Chornobyl Nuclear Power Plant in Ukraine, along with an analysis of the available literature. Significant differences exist in ⁵⁴Mn, ⁶⁰Co, and ⁶⁵Zn accumulation levels among the different fish species. Food intake is the primary pathway for these radionuclides to enter the fish organisms. These radionuclides accumulate differently in various organs and tissues. There is no consensus on the specific organ that primarily accumulates each radionuclide. In most studies, the highest concentrations of ⁵⁴Mn have been recorded in internal organs. The kidneys are identified as the main organ accumulating ⁶⁰Co. The highest concentrations of ⁶⁵Zn are typically found in the liver and kidneys; however, significant accumulation is also noted in external organs and tissues (gills, fins). In most cases, the lowest concentrations of ⁵⁴Mn, ⁶⁰Co, and ⁶⁵Zn are observed in the muscle tissues of fish. Full article

23 pages, 1530 KiB

Open AccessArticle

Investigation of Plasticity in Morphology, Organ Traits and Nutritional Composition in Chinese Soft-Shelled Turtle (Pelodiscus sinensis) Under Different Culturing Modes

by Ming Qi, Yang Wang, Liangliang Hu, Guangmei Chen, Tianlun Zheng, Xueyan Ding, Yijiang Bei, Jianjun Tang, Wenjun Ma and Xin Chen

Fishes 2025, 10(3), 89; https://doi.org/10.3390/fishes10030089 - 20 Feb 2025

Abstract

The Chinese soft-shelled turtle (Pelodiscus sinensis) is an aquatic reptile prized for its nutritional and health benefits. Given its adaptability to various culturing modes including the greenhouse, pond and rice culturing modes, we conducted a comparative analysis of the morphology, organ [...] Read more.

The Chinese soft-shelled turtle (Pelodiscus sinensis) is an aquatic reptile prized for its nutritional and health benefits. Given its adaptability to various culturing modes including the greenhouse, pond and rice culturing modes, we conducted a comparative analysis of the morphology, organ trait and nutritional composition of turtles cultured in three culturing modes. This study investigated the plasticity of morphology and physiology, as well as the variations in nutritional composition across varying culturing modes. The results demonstrated that after approximately 120 days of cultivation, significant changes were observed in the morphology, physiology and nutritional composition of turtles from each culturing mode. In terms of morphology, rice turtles exhibited an arched shell shape, broad plastron, elongated limbs, narrow interocular distance and slender head and neck. Pond turtles displayed similar morphological characteristics to rice turtles, with the additional features of a flattened body shape and narrower plastron. Greenhouse turtles presented a flattened shell shape, narrow plastron, shortened limbs, wider interocular distance and stocky head and neck. Regarding the organ characteristics, the specific weights of liver, viscera, internal fat lumps and condition factors were significantly higher in greenhouse turtles compared to rice turtles and pond turtles (p < 0.05). Conversely, the specific weights of the back carapace, calipash and edible part were significantly lower than those in rice turtles and pond turtles (p < 0.05). Nutritional analysis revealed that crude protein, total amino acid, essential amino acid, flavor amino acid, pharmacodynamic amino acid, collagen and EPA+DHA contents were significantly higher in rice turtles and pond turtles than greenhouse turtles (p < 0.05). However, crude fat and unsaturated fatty acid contents were significantly higher in greenhouse turtles than in rice turtles and pond turtles (p < 0.05). In summary, Chinese soft-shelled turtles exhibited significant morphological and organ plasticity in response to different culturing modes. While the rice and pond culturing modes could enhance the nutritional quality of turtles to some extent, the impact of commercial feed on fatty acid profiles must be carefully considered. Full article

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27 pages, 9925 KiB

Open AccessArticle

Redefining Aquaculture Safety with Artificial Intelligence: Design Innovations, Trends, and Future Perspectives

by Feng Ma, Zewen Fan, Anna Nikolaeva and Haoran Bao

Fishes 2025, 10(3), 88; https://doi.org/10.3390/fishes10030088 - 20 Feb 2025

Abstract

In recent years, safety concerns in aquaculture have become increasingly prominent due to various factors. Concurrently, the emergence of artificial intelligence (AI) has offered novel approaches to addressing these challenges. This paper provides a comprehensive review and synthesis of AI applications in aquaculture [...] Read more.

In recent years, safety concerns in aquaculture have become increasingly prominent due to various factors. Concurrently, the emergence of artificial intelligence (AI) has offered novel approaches to addressing these challenges. This paper provides a comprehensive review and synthesis of AI applications in aquaculture safety over the past few decades, while also suggesting future directions. Utilizing bibliometric tools such as Citespace and VOSviewer, we analyzed 513 publications spanning from 1998 to 2025. Our analysis highlighted a growing global research interest in this emerging field. Furthermore, it is forecasted that the integration of remote sensing technology, immune response monitoring, and cross-disciplinary innovations will drive the transformation of aquaculture safety management toward a more intelligent, proactive, and sustainable approach. These advancements are expected to enhance the precision and efficiency of risk assessment and disease prevention in aquaculture systems. Full article

(This article belongs to the Special Issue Safety Management in Fish Farming: Challenges and Further Trends)

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20 pages, 289 KiB

Open AccessArticle

Has Finance Promoted High-Quality Development in China’s Fishery Economy?—A Perspective on Formal and Informal Finance

by Shengchao Ye, Qian Zhang, Xiao Li, Jianli Yu and Haohan Wang

Fishes 2025, 10(2), 87; https://doi.org/10.3390/fishes10020087 - 19 Feb 2025

Abstract

The high-quality development of China’s fishery economy serves as its core objective, with robust financial support playing a pivotal role. This study employs provincial panel data spanning 2005 to 2020 and utilizes the entropy method to evaluate the level of high-quality development in [...] Read more.

The high-quality development of China’s fishery economy serves as its core objective, with robust financial support playing a pivotal role. This study employs provincial panel data spanning 2005 to 2020 and utilizes the entropy method to evaluate the level of high-quality development in China’s fishery economy across three dimensions: fundamental security, sustainability, and comprehensive efficiency. From the perspectives of formal and informal finance, it compares their support effects on different aspects of high-quality development in China’s fishery economy, while also exploring the mechanisms underlying these effects by considering factors such as industrial uncertainty and economic scale. The findings indicate that, overall, the support provided by both formal and informal finance for high-quality development in the fishery economy is insufficient. Further analysis reveals a significant threshold effect of fishery economic scale, with turning points at 108.44 billion CNY and 232.98 billion CNY for formal and informal finance, respectively. For higher-level indicators, such as sustainability and comprehensive efficiency, formal and informal financial systems demonstrate complementary roles, depending on the scale of the regional fishery economy. Furthermore, industrial uncertainty serves as a significant mediating factor only for formal financial support, with the levels of sustainability and comprehensive efficiency most affected. Full article

(This article belongs to the Section Fishery Economics, Policy, and Management)

15 pages, 3996 KiB

Open AccessArticle

Methyltransferase HsdM Regulates the Pathogenicity of Streptococcus agalactiae to Nile Tilapia (Oreochromis niloticus)

by Dongdong Jiang, Bei Wang, Yan Ren, Xubing Mo, Meiling Yu and Defeng Zhang

Fishes 2025, 10(2), 86; https://doi.org/10.3390/fishes10020086 - 19 Feb 2025

Abstract

DNA methylation is a critical mechanism for regulating gene expression in bacteria and plays an essential role in bacterial pathogenesis. A mutant, WC1535ΔhsdM, lacking hsdM encoding a DNA methyltransferase was constructed using homologous recombination technology. The growth, hemolytic activity, and capsule [...] Read more.

DNA methylation is a critical mechanism for regulating gene expression in bacteria and plays an essential role in bacterial pathogenesis. A mutant, WC1535ΔhsdM, lacking hsdM encoding a DNA methyltransferase was constructed using homologous recombination technology. The growth, hemolytic activity, and capsule formation of the mutant were analyzed. The dynamic distribution of the wild-type (WT) and mutant strains in tilapia tissues after artificial infection was determined. The adhesion, invasion, anti-phagocytic, and whole-blood survival abilities of the WT and mutant strains were analyzed. Tilapia were intraperitoneally injected with the WT or mutant strains, and the LD₅₀ values were determined. The expression levels of the immune-related genes in tilapia were analyzed by qRT-PCR. The mutant showed faster growth during the logarithmic growth period (5–10 h) and lower hemolytic activity than the WT strain. Mutant loads in tilapia tissues were significantly lower than those of the WT strain. Mutant strain adhesion to epithelial cells was significantly reduced, it was more easily engulfed by macrophages, and it had decreased intracellular survival. The LD₅₀ of the mutant was 2.06 times higher than that of the WT strain, indicating decreased pathogenicity. Expression levels of immune-related genes IL-1β, IL-6, IFN-γ, and TNF-α in tilapia induced by the mutant were lower than those by the WT strain. In conclusion, the WC1535ΔhsdM mutant exhibited an increased growth rate and decreased hemolytic activity, tissue colonization, and pathogenicity, indicating that HsdM could regulate S. agalactiae growth and pathogenicity. This study provides new insights into the pathogenesis of piscine S. agalactiae. Full article

(This article belongs to the Special Issue Prevention and Control of Aquatic Animal Diseases)

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15 pages, 934 KiB

Open AccessArticle

Investigating the Benefits of Integrating Rainbow Trout (Oncorhynchus mykiss) and Lettuce (Lactuca sativa) Cultivation in California

by Duncan Gwynne, Pallab K. Sarker, Anne R. Kapuscinski, Benjamin V. Schoffstall, Devin Fitzgerald, Megan Deevy, Joji Muramoto, Uchasha Sarker, Stavros Boutris, Catalina Sutter, Emily Thompson and Lucas Raymond

Fishes 2025, 10(2), 85; https://doi.org/10.3390/fishes10020085 - 19 Feb 2025

Abstract

Global food production, both aquatic and terrestrial, is rife with sustainability issues. Aquaculture is a rapidly growing industry that is on track to surpass wild-caught fishery production by 2030. The integration of aquaculture and agriculture systems could help to reduce some of their [...] Read more.

Global food production, both aquatic and terrestrial, is rife with sustainability issues. Aquaculture is a rapidly growing industry that is on track to surpass wild-caught fishery production by 2030. The integration of aquaculture and agriculture systems could help to reduce some of their respective and shared environmental issues. Integrated Aquaculture–Agriculture (IAA) has been shown to provide a variety of benefits to both aquaculture and agriculture including increased system water use efficiency (WUE), a reduction in fertilizer use, and increases in total farm yield and resilience. This study was performed to examine the potential for rainbow trout aquaculture effluent to improve the yield, nutrient composition, and WUE of lettuce, as well as act as a partial fertilizer replacement. We used four irrigation treatments throughout the experiment: city water, aquaculture effluent, city water with added organic fertilizer, and aquaculture effluent with added organic fertilizer. Throughout the trial, there were some issues of herbivory in the growing plot, but overall, the lettuce receiving city water with organic fertilizer (30. ± 3.4 g/plant) showed significantly higher fresh biomass than effluent treatments (18 ± 1.4 g/plant and 17 ± 2.9 g/plant) at the end of the trial. We did not detect any significant differences among treatments in the macro- and micronutrients of the lettuce shoots and roots. However, the WUE of effluent treatments (4.4 ± 0.030 kg/m³ and 1.0 ± 0.070 kg/m³) was greater than that of organic fertilizer (0.28 ± 0.050 kg/m³) and control treatments (0.23 ± 0.040 kg/m³). The results indicate that adopting IAA in California could improve statewide WUE and conserve water for sustainable agricultural production. Full article

(This article belongs to the Section Sustainable Aquaculture)

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16 pages, 676 KiB

Open AccessReview

CRISPR-Based Genetic Improvement of Aquaculture Species

by Abdulkadir Bayır, Selma Saoula, Ammar Almansour, Deshou Wang, Mehtap Bayır, Burcu Naz Uzun, Serpil Turhan, Harun Arslan and Gökhan Arslan

Fishes 2025, 10(2), 84; https://doi.org/10.3390/fishes10020084 - 18 Feb 2025

Abstract

The clustered regularly interspaced short palindromic repeat-associated protein (CRISPR-Cas) system is considered a potential game-changer in the aquaculture sector. The CRISPR-Cas9 system is derived from an adaptive mechanism of the immune system of some prokaryotes. The CRISPR/Cas9 system potentially accelerates the rate of [...] Read more.

The clustered regularly interspaced short palindromic repeat-associated protein (CRISPR-Cas) system is considered a potential game-changer in the aquaculture sector. The CRISPR-Cas9 system is derived from an adaptive mechanism of the immune system of some prokaryotes. The CRISPR/Cas9 system potentially accelerates the rate of sustained genetic gain for the aquaculture and seafood production sectors. Unlike conventional genome-editing techniques, CRISPR/Cas9 is more cost-effective, user-friendly, and extremely precise. It enables overcoming large-scale challenges in aquaculture. Traits such as high fertility, external fertilization, shorter generation time, well-established breeding methods, and the ability to raise larvae offer potential benefits for applying CRISPR/Cas9 genome editing in most aquacultural species. The use of genome editing accelerates precise breeding where desired modifications are made to the target gene. There is a high likelihood that the intended alterations will be achieved, resulting in the transmission of the desired trait to the next generation. In this paper, we review how the CRISPR system evolved, its basic categories and different Cas systems, as well as the molecular mechanism of CRISPR/Cas. We also highlight and discuss the potential applications of CRISPR/Cas in the aquaculture industry. Moreover, the challenges of using CRISPR/Cas technology are briefly discussed. This pathway charts a course to a future in which genome editing has the potential to enable aquaculture to fulfill world food requirements with public and ecological safety. Full article

(This article belongs to the Section Genetics and Biotechnology)

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10 pages, 986 KiB

Open AccessArticle

Incorrect Identification in the Marketing of Serrasalmid Fishes: A Threat to Native Species and Productivity in the Aquaculture Industry

by Diego G. Martins, Fernanda D. Prado, Ricardo Utsunomia, Diogo Teruo Hashimoto, Caio Augusto Gomes Goes, Fausto Foresti, Carlos Egberto Rodrigues Junior and Fabio Porto-Foresti

Fishes 2025, 10(2), 83; https://doi.org/10.3390/fishes10020083 - 18 Feb 2025

Abstract

Interspecific hybridization can offer advantages in fish aquaculture by enhancing traits like growth rate and disease resistance. However, improper management can result in heterogeneous breeding stocks, which pose risks if hybrids interbreed with native populations. This can lead to loss of genetic diversity [...] Read more.

Interspecific hybridization can offer advantages in fish aquaculture by enhancing traits like growth rate and disease resistance. However, improper management can result in heterogeneous breeding stocks, which pose risks if hybrids interbreed with native populations. This can lead to loss of genetic diversity and alterations in population structure. This study aimed to evaluate the prevalence of hybridization within the Brazilian aquaculture industry, focusing on the economically significant Serrasalmid species, such as Piaractus mesopotamicus (pacu), Piaractus brachypomus (pirapitinga), Colossoma macropomum (tambaqui), and their hybrids. Using molecular markers (TROP and APOC SNP markers), 312 individuals from the Companhia de Entrepostos e Armazéns Gerais de São Paulo (CEAGESP), the largest warehouse in Latin America, were assessed. The results revealed that 80% of the samples were misidentified, with a substantial proportion of hybrids (72.12%). Among these hybrids, 71.6% were classified as F1 hybrids, while 28.4% were post-F1 hybrids. These findings highlight the need for improved genetic monitoring and management practices in Brazil’s fish production industry, emphasizing the importance of sustainable practices to ensure the long-term viability of aquaculture while preserving native genetic resources. Full article

(This article belongs to the Section Sustainable Aquaculture)

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12 pages, 1069 KiB

Open AccessArticle

Portable Smoking Ovens: What Are the PAH Levels in Grilled and Smoked Rainbow Trout?

by Paul Uiuiu, Daniel Cocan, Călin Lațiu, Radu Constantinescu, Vioara Mireșan, Tudor Papuc, Raul-Lucian Savin, Andrada Ihuț, Camelia Răducu, Anca Becze, Cristina Craioveanu and Bogdan Alin Vlaic

Fishes 2025, 10(2), 82; https://doi.org/10.3390/fishes10020082 - 18 Feb 2025

Abstract

Fish smoking is one of the oldest preservation methods and has traditional forms in most parts of the world, each with distinct variables. The presence of PAHs in smoked fish is of great concern for producers and consumers alike, as PAHs have great [...] Read more.

Fish smoking is one of the oldest preservation methods and has traditional forms in most parts of the world, each with distinct variables. The presence of PAHs in smoked fish is of great concern for producers and consumers alike, as PAHs have great negative effects on human health. This study aimed to determine the physicochemical characteristics and polycyclic aromatic hydrocarbons (PAHs) content level in smoked rainbow trout Oncorhynchus mykiss (Walbaum, 1792) processed using a commercial portable grilling and smoking oven. Sawdust of hardwood (beech, cherry, sour cherry, walnut, and plum) and softwood (fir, willow) were used to produce aromatic essences. The principal component analysis (PCA) revealed that different tree species tend to accumulate different PAHs in different concentrations. In the case of the generalized additive model (GAM) analyzing fish meat, fir tree reduced the concentration of PAHs in fish meat. When GAM analyzed fish skin, cherry, sour cherry, and willow trees significantly reduced the concentrations of PAHs in fish skin compared to beech trees. Furthermore, the results regarding the skin of the fish suggest that it acts as a protective barrier, trapping smoke particulates and reducing the penetration of PAHs into the meat. The present method clearly shows that, at least in the case of Benzo[a]pyrene, it is safer than traditional methods of smoking. This highlights the need for further research into the physicochemical properties of fish tissue and their impact on PAH accumulation. Full article

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20 pages, 10296 KiB

Open AccessArticle

Utilizing an Enhanced YOLOv8 Model for Fishery Detection

by Hanyu Jiang, Jiacheng Zhong, Fuyu Ma, Cheng Wang and Ruiwen Yi

Fishes 2025, 10(2), 81; https://doi.org/10.3390/fishes10020081 - 17 Feb 2025

Abstract

Due to the complexity of underwater lighting, image clarity and color are significantly affected. Furthermore, in the underwater environment, marine organisms often blend into the background due to their similar colors, making them difficult to distinguish. These organisms are often obscured by various [...] Read more.

Due to the complexity of underwater lighting, image clarity and color are significantly affected. Furthermore, in the underwater environment, marine organisms often blend into the background due to their similar colors, making them difficult to distinguish. These organisms are often obscured by various obstacles, and there are varying degrees of overlap between them, posing substantial challenges for underwater object detection using deep learning methods. To address these challenges, we developed an improved object detection model based on YOLOv8, which is robust and less sensitive to noise. We designed the Global Context 3D Perception Module (GC3DPM) to enable global context feature modeling and 3D perception. Additionally, we introduced the Channel Aggregation Efficient Downsampling Block (CAEDB) for more efficient upsampling and to improve the network’s expressive power and information flow through channel aggregation functionality. We further optimized the detection head for more effective use of the top-layer network’s rich semantic information, and addressed the class imbalance that was present in the data. Our proposed method achieves 82.1% precision, 76.5% recall, 79.2% F1-score, 83.3% mAP50, and 48.6% mAP50-95, while reducing the parameter count by 8.3%. The results demonstrate that our method provides an efficient and reliable automatic detection technology for precision underwater fishing. Full article

(This article belongs to the Special Issue Technology for Fish and Fishery Monitoring)

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18 pages, 3322 KiB

Open AccessArticle

Seasonal Fluctuations in Geosmin and Terpenes in Rainbow Trout (Oncorhynchus mykiss) in an Outdoor Commercial Recirculated Aquaculture System Facility

by Raju Podduturi, Mikael Agerlin Petersen, Peter Stougaard and Niels O. G. Jørgensen

Fishes 2025, 10(2), 80; https://doi.org/10.3390/fishes10020080 - 17 Feb 2025

Abstract

Seasonal changes in geosmin and selected terpenes in rainbow trout (Oncorhynchus mykiss) in an outdoor recirculated aquaculture system (RAS) in Denmark were followed over three months. In the water, geosmin varied from 4.1 to 25.7 ng/L, but no seasonal trends were [...] Read more.

Seasonal changes in geosmin and selected terpenes in rainbow trout (Oncorhynchus mykiss) in an outdoor recirculated aquaculture system (RAS) in Denmark were followed over three months. In the water, geosmin varied from 4.1 to 25.7 ng/L, but no seasonal trends were obvious. Variable trends occurred for geosmin relative to concentrations of inorganic N (ammonium, nitrite, and nitrate) and phosphate, and did not indicate a general relationship. The geosmin content of the fish ranged from 669 to 2264 ng/kg and covaried with geosmin in the water. The average number of the geoA gene (encoding geosmin synthase) was 2.41 × 10⁵ copies/L in the water and 3.29 × 10⁷ copies on each bio-element in the biofilter. In only one of the three examined RAS units, geosmin in the water and on the bio-elements covaried with the number of geoA copies. Among the identified four terpenes in the fish flesh, α-pinene was dominant and made up 55.9–62.8% of the terpenes. The presence of aroma-active terpenes in the fish suggests that not only geosmin concentrations should be considered when characterizing taste profiles of farmed rainbow trout. Full article

(This article belongs to the Section Sustainable Aquaculture)

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19 pages, 1472 KiB

Open AccessArticle

Accounting for Carbon Emissions from Fisheries in China and Analyzing the Decoupling Effect

by Zhiyao Xia and Dameng Hu

Fishes 2025, 10(2), 79; https://doi.org/10.3390/fishes10020079 - 16 Feb 2025

Abstract

This study evaluated the carbon emissions as one of the environmental impacts of fishing activities in China during the period of 2010–2022. The decoupling effect of fishery carbon emissions and fishery economic growth was analyzed using a decoupling model. The findings reveal that [...] Read more.

This study evaluated the carbon emissions as one of the environmental impacts of fishing activities in China during the period of 2010–2022. The decoupling effect of fishery carbon emissions and fishery economic growth was analyzed using a decoupling model. The findings reveal that China’s fishery carbon emissions are substantial and exhibit multi-stage variations. Inland areas mainly emit carbon from aquatic feed decomposition and aquaculture equipment electricity consumption, with differing structures between high- and low-emission regions. Coastal areas primarily emit carbon from fishing, supplemented by aquatic feed. From 2010 to 2011, decoupling was poorly idealized as strong negative decoupling, but post-2011 featured mainly weak decoupling with strong decoupling as a complement. After excluding economic factors, carbon intensity and population size positively influenced decoupling, with intensity initially leading and scale later expanding. Structural factors mainly hindered decoupling. Full article

(This article belongs to the Special Issue Fishing Gear Technology and Conservation of Fishery Resources)

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24 pages, 6158 KiB

Open AccessArticle

Effects of Fish Meal Replacement with Poultry By-Product Meal on Growth Performance, Lipid Metabolism, Hepatic–Intestinal Health and Ammonia Nitrogen Stress in Siniperca chuatsi

by Shulin Tang, Huanchao Ma, Xueming Hua, Lei Wang, Biao Yun, Xuan Zhu and Xueqiao Qian

Fishes 2025, 10(2), 78; https://doi.org/10.3390/fishes10020078 - 15 Feb 2025

Abstract

Fish meal (FM) replacement is essential for sustainable aquaculture development. This study investigated the effects of FM replacement with poultry by-product meal (PBM) on growth performance, hepatic and intestinal health and ammonia nitrogen stress resistance in mandarin fish (Siniperca chuatsi). A [...] Read more.

Fish meal (FM) replacement is essential for sustainable aquaculture development. This study investigated the effects of FM replacement with poultry by-product meal (PBM) on growth performance, hepatic and intestinal health and ammonia nitrogen stress resistance in mandarin fish (Siniperca chuatsi). A 52-day feeding trial was conducted using PBM to replace fish meal at levels of 0%, 17.5%, 35.0%, 52.5% and 70.0%. The results showed that FM replacement with PBM did not influence growth performance in mandarin fish. Moderate PBM replacement (≤35.0%) did not harm liver health and enhanced the intestinal structure. However, excessive replacement (≥52.5%) caused hepatocyte damage, reduced antioxidant capacity and decreased survival under ammonia nitrogen stress. Notably, 70% PBM replacement led to severe hepatic lipid accumulation, inhibiting fatty acid β-oxidation and triglyceride hydrolysis pathways. Furthermore, high PBM levels (≥52.5%) also reduced intestinal muscularis thickness, downregulated tight junction proteins and induced inflammation. In conclusion, while PBM replacement does not hinder growth, maintaining levels below 35.0% (PBM ≤ 28.5%) is essential for preserving hepatic lipid metabolism, intestinal health and antioxidant defense in mandarin fish. Full article

(This article belongs to the Section Nutrition and Feeding)

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12 pages, 3546 KiB

Open AccessArticle

Antiviral Effect and Metabolic Regularity of a Phenylpropanoid- Based Compound as Potential Immunopotentiator

by Dawei Song, Xue Cai, Qianhao Shao, Xinhui Tong, Zhe Zhao, Lei Liu and Guanglu Liu

Fishes 2025, 10(2), 77; https://doi.org/10.3390/fishes10020077 - 15 Feb 2025

Abstract

Spring viremia of carp virus (SVCV) is a significant pathogen that has notably hindered the advancement of cyprinid aquaculture in recent years. Infections caused by SVCV are often associated with substantial economic losses due to the absence of effective treatment options. Previous reports [...] Read more.

Spring viremia of carp virus (SVCV) is a significant pathogen that has notably hindered the advancement of cyprinid aquaculture in recent years. Infections caused by SVCV are often associated with substantial economic losses due to the absence of effective treatment options. Previous reports indicated that N-(4-methyl-2-oxo-2H-chromen-7-yl) benzenesulfonamide (N6) exhibits inhibitory effects on SVCV proliferation. This study aims to comprehensively evaluate the anti-SVCV effects of N6 using healthy young carp as the experimental model. The research investigates the antiviral activity of this compound in vivo, the immune response of interferon (IFN)-related genes, its impact on the horizontal transmission of SVCV, and histopathological changes. The results indicate that N6 significantly inhibits SVCV infectivity and apoptosis in EPC cells in vitro. Furthermore, while N6 reduced horizontal transmission of SVCV in a static cohabitation challenge model, the N6-treated SVCV-infected group showed a nearly 3-fold decrease in viral load compared to the control group, it did not completely prevent transmission at established antiviral dosages. Histopathological analysis of the affected fish revealed that N6 effectively mitigated tissue damage induced by SVCV. Additionally, the up-regulation of six IFN-related genes suggests that N6 may indirectly activate IFNs to facilitate the clearance of SVCV in the kidney and spleen, as demonstrated by quantitative reverse transcription polymerase chain reaction (qRT-PCR). These findings provide a foundation for further investigations into the mechanisms by which N6 acts against SVCV and may aid in the development of novel anti-SVCV therapeutics. Full article

(This article belongs to the Section Nutrition and Feeding)

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20 pages, 302 KiB

Open AccessArticle

Effects of Chicken By-Product Meal as a Fish Meal Replacer in Diets With or Without Jack Mackerel Meal Inclusion: Growth and Feed Availability for Rockfish (Sebastes schlegeli)

by June Kim, Yu Jin Sim and Sung Hwoan Cho

Fishes 2025, 10(2), 76; https://doi.org/10.3390/fishes10020076 - 14 Feb 2025

Abstract

The current experiment is conducted to determine the effects of chicken by-product meal (CBM) as a fish meal (FM) replacer in diets, with or without the inclusion of jack mackerel (Trachurus japonicus) meal (JMM), on the growth and feed availability of [...] Read more.

The current experiment is conducted to determine the effects of chicken by-product meal (CBM) as a fish meal (FM) replacer in diets, with or without the inclusion of jack mackerel (Trachurus japonicus) meal (JMM), on the growth and feed availability of rockfish (Sebastes schlegeli). A two-way ANOVA experimental design [FM replacement level (FMRL, 25% and 50%) × JMM inclusion (without and with)] was adopted. The control (Con) diet contained 55% FM. In the Con diet, 25% and 50% of FM were substituted with CBM, either without or with the inclusion of 22% JMM, referred to as the CBM25, CBM50, CBM25J, and CBM50J diets, respectively. A total of 375 juvenile fish were distributed into 15 tanks with triplicates. The 25% FM replacement diets led to significantly (p < 0.003 and p < 0.004, respectively) greater weight gain and specific growth rate (SGR) of rockfish than the 50% FM replacement diets. Furthermore, the CBM-replaced diets with JMM inclusion led to significantly (p < 0.003 and p < 0.002, respectively) greater weight gain and SGR of fish compared with those without JMM inclusion. Weight gain and SGR of rockfish fed the Con and CBM25J diets were significantly (p < 0.001 for both) greater than those of fish fed the CBM25, CBM50, and CBM50J diets. However, neither dietary FMRL nor JMM inclusion had significant (p > 0.05) effects on feed consumption, blood chemistry, or the biochemical composition of rockfish. In conclusion, 25% of FM could be replaced with CBM in the 55% FM-based diet, including JMM, without adverse effects on the growth, feed availability, blood chemistry, or biochemical composition (proximate composition and amino and fatty acid profiles) of rockfish. Full article

(This article belongs to the Section Nutrition and Feeding)

24 pages, 5201 KiB

Open AccessArticle

A Deep Learning Approach to Automated Treatment Classification in Tuna Processing: Enhancing Quality Control in Indonesian Fisheries

by Johan Marcus Tupan, Fredrik Rieuwpassa, Beni Setha, Wilma Latuny and Samuel Goesniady

Fishes 2025, 10(2), 75; https://doi.org/10.3390/fishes10020075 - 13 Feb 2025

Abstract

The Indonesian maritime territory harbors a rich diversity of marine resources, making up approximately 37% of global fish species diversity. Tuna, particularly in Maluku Province, stands out as a vital economic asset with growing production and export numbers. Current practices for processing and [...] Read more.

The Indonesian maritime territory harbors a rich diversity of marine resources, making up approximately 37% of global fish species diversity. Tuna, particularly in Maluku Province, stands out as a vital economic asset with growing production and export numbers. Current practices for processing and evaluating tuna meat, however, face significant limitations due to basic infrastructure and reliance on manual inspection methods, leading to potential contamination risks and treatment identification errors. This research addresses these challenges by implementing an advanced deep learning solution based on convolutional neural networks (CNNs) to automatically identify three distinct treatment categories for tuna loin: No-Treatment, CO-Treatment, and CS-Treatment. Trained on a comprehensive image dataset, the model demonstrated exceptional performance with 95% accuracy. While field testing confirmed the model’s strong performance in correctly identifying treatment categories, occasional classification errors highlighted areas for improvement in data preprocessing. This study provides a significant step forward in automated fish processing assessment technology, offering a promising solution to longstanding challenges in the marine processing industry. Full article

(This article belongs to the Special Issue Management and Technology for Tuna Fisheries)

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23 pages, 3009 KiB

Open AccessReview

Advancing Fisheries Research and Management with Computer Vision: A Survey of Recent Developments and Pending Challenges

by Jesse Eickholt, Jonathan Gregory and Kavya Vemuri

Fishes 2025, 10(2), 74; https://doi.org/10.3390/fishes10020074 - 12 Feb 2025

Abstract

The field of computer vision has progressed rapidly over the past ten years, with noticeable improvements in techniques to detect, locate, and classify objects. Concurrent with these advances, improved accessibility through machine learning software libraries has sparked investigations of applications across multiple domains. [...] Read more.

The field of computer vision has progressed rapidly over the past ten years, with noticeable improvements in techniques to detect, locate, and classify objects. Concurrent with these advances, improved accessibility through machine learning software libraries has sparked investigations of applications across multiple domains. In the areas of fisheries research and management, efforts have centered on the localization of fish and classification by species, as such tools can estimate the health, size, and movement of fish populations. To aid in the interpretation of computer vision for fisheries research management tasks, a survey of the recent literature was conducted. In contrast to prior reviews, this survey focuses on employed evaluation metrics and datasets as well as the challenges associated with applying machine learning to a fisheries research and management context. Misalignment between applications and commonly used evaluation metrics and datasets mischaracterizes the efficacy of emerging computer vision techniques for fisheries research and management tasks. Aqueous, turbid, and variable lighted deployment settings further complicate the use of computer vision and generalizability of the reported results. Informed by these inherent challenges, culling surveillance data, exploratory data collection in remote settings, and selective passage and traps are presented as opportunities for future research. Full article

(This article belongs to the Section Fishery Economics, Policy, and Management)

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23 pages, 5624 KiB

Open AccessArticle

Heat Shock Factors in the European Eel: Gene Characterization and Expression Response to Different Environmental Conditions and to Induced Sexual Maturation

by Leonor Ferrão, Luz Pérez, Juan F. Asturiano and Marina Morini

Fishes 2025, 10(2), 73; https://doi.org/10.3390/fishes10020073 - 12 Feb 2025

Abstract

Heat shock factors (HSFs) are transcription factors that regulate responses to environmental changes and play roles in physiological mechanisms like spermatogenesis. This study analyzed the HSF gene family and their expression profiles in the European eel under different environmental conditions and during testis [...] Read more.

Heat shock factors (HSFs) are transcription factors that regulate responses to environmental changes and play roles in physiological mechanisms like spermatogenesis. This study analyzed the HSF gene family and their expression profiles in the European eel under different environmental conditions and during testis maturation. Six HSF genes were identified in the studied vertebrates, in which the eel presents two HSF1 paralogs (HSF1a and HSF1b), likely resulting from the teleost whole-genome duplication event, while only one paralog is present for the other HSF (HSF2, HSF4, and HSF5). All five HSF genes were highly expressed in the testis, but some were also detected in the brain, intestine, and gills. Our findings showed that HSF1 changed their expression in response to different temperature and salinity conditions, suggesting that these may support males in perceiving the temperature and salinity changes possibly found during reproductive migration. During hCGrec-induced spermatogenesis, HSF genes presented a decreasing expression profile throughout testis maturation (with significant differences in HSF1a and HSF4), except HSF5, which showed the highest levels after 4 weeks of hormonal treatment. Our study indicates that HSF genes are potentially implicated in the response to environmental changes perception and during gonadal maturation. Full article

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