Fishes

22 pages, 1782 KiB

Open AccessArticle

Validation of a Health Characterization Model for Tilapia Farming in a Brazilian Federative Unit

by R. S. Raposo, N. V. B. Oliveira, M. K. V. C. Delphino, C. A. G. Leal, A. L. A. A. Mota and F. J. F. Sant’Ana

Fishes 2024, 9(11), 469; https://doi.org/10.3390/fishes9110469 - 20 Nov 2024

Viewed by 331

Abstract

Brasília, Distrito Federal, is among the Brazilian cities with the highest number of tilapia farms, with around 660 farms, of which 112 are commercial. The aim of this study was to validate a health characterization model for commercial tilapia production using the production [...] Read more.

Brasília, Distrito Federal, is among the Brazilian cities with the highest number of tilapia farms, with around 660 farms, of which 112 are commercial. The aim of this study was to validate a health characterization model for commercial tilapia production using the production chain in the Distrito Federal (DF), one of Brazil’s 27 federative units, by applying a semi-structured questionnaire. A total of 112 farms were categorized according to the degree of vulnerability to the introduction of pathogens and the risk of dissemination using two weighted scorecard tables that evaluated 15 items each. After calculating the mean between the two variables, the farms were classified from A (insignificant risk) to D (high risk). Most of the commercial tilapia farms in the Distrito Federal were categorized as B (39; 34.8%) and C (53; 47.3%), representing low and medium risk, respectively. When comparing the different commercial groups, a significant difference (p < 0.05) was observed in the mean scores between closed-system fattening farms and both semi-closed fattening farms and pay-to-fish farms. Closed-system fattening farms, such as those using biofloc, aquaponics, and recirculation aquaculture systems, showed the lowest vulnerability to pathogen entry and the lowest risk of disease spread. The study’s findings provide valuable health information for the official veterinary service of the DF, enabling the categorization of farms, identification of production units, and determination of the most vulnerable strata. Furthermore, the model can be easily applied by private companies and by official veterinary services in other states or countries with significant tilapia production that need to implement risk-based surveillance programs for tilapia farms. Full article

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

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10 pages, 1933 KiB

Open AccessArticle

Integrate Analysis of Eyestalk Proteome and Metabolome in Precocious and Formal Juvenile Female Eriocheir sinensis

by Tingshuang Pan, Min Yang, Tong Li, He Jiang and Jun Ling

Fishes 2024, 9(11), 468; https://doi.org/10.3390/fishes9110468 - 18 Nov 2024

Viewed by 281

Abstract

The Chinese mitten crab (Eriocheir sinensis) is an economically important crustacean. With the development of the E. sisnensis industry, precocity has become a significant challenge in juvenile crab culturing. In this study, the eyestalks of female E. sinensis from precocious (PE) [...] Read more.

The Chinese mitten crab (Eriocheir sinensis) is an economically important crustacean. With the development of the E. sisnensis industry, precocity has become a significant challenge in juvenile crab culturing. In this study, the eyestalks of female E. sinensis from precocious (PE) and normal juvenile (NE) groups were used for proteome and metabolome analyses. In total, 731 up-regulated and 657 down-regulated differentially expressed proteins (DEPs) were identified in the PE and NE groups. In addition, 110 differentially expressed metabolites (DMs) were up-regulated and 256 were down-regulated in the PE group. An integrated analysis showed 5667 significant correlations between the metabolites and proteins and 109 common pathways in the proteome and metabolome. The proteins were mostly associated with the mechanistic target of rapamycin (mTOR) pathway, longevity regulation, autophagy, and the pyrimidine and purine metabolism pathways. The metabolites were primarily enriched in amino acid and lipid metabolisms. These results demonstrated the differences in the PE and NE groups at two omics levels and will be useful for the E. sinensis industry. Full article

(This article belongs to the Special Issue Interactions between Fish and Pathogens in Aquaculture—2nd Edition)

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15 pages, 474 KiB

Open AccessArticle

Effects of Carnosine Addition in Low-Fishmeal Feed on the Growth Performance, Muscle Antioxidant Capacity and Flesh Quality of Orange-Spotted Grouper (Epinephelus coioides)

by Dong Li, Weijun Chen, Yanxia Yin, Lulu Yang, Mingfan Chen, Yunzhang Sun and Jidan Ye

Fishes 2024, 9(11), 467; https://doi.org/10.3390/fishes9110467 - 18 Nov 2024

Viewed by 280

Abstract

Carnosine is a natural dipeptide made up of L-histidine and β-alanine which is rich in muscle tissues and has multiple physiological functions. The current research aimed to investigate the effects of varied carnosine concentrations in low-fishmeal feed on the growth, muscle antioxidant capacity [...] Read more.

Carnosine is a natural dipeptide made up of L-histidine and β-alanine which is rich in muscle tissues and has multiple physiological functions. The current research aimed to investigate the effects of varied carnosine concentrations in low-fishmeal feed on the growth, muscle antioxidant capacity and flesh quality of orange-spotted grouper. Carnosine was supplemented at doses of 0, 10, 20, 40, 80, 160, and 320 mg/kg in low-fishmeal feed. Seven groups with three tanks of fish (11.4 ± 0.1 g/fish) were allotted one of the diets during the 8-week feeding trial. The growth rate, body protein content, muscle activities of superoxide dismutase and catalase, and muscle adhesiveness showed positive linear response and/or an open upward parabola with increasing carnosine concentrations, with a peak at 160 mg/kg of carnosine. Feed utilization, serum total protein content, gut trypsin activity, muscle glutathione peroxidase, total antioxidant capacity, muscle hardness, gumminess, chewiness and resilience followed the same pattern as the growth rate, reaching a peak at 320 mg/kg of carnosine; while the opposite trend was observed, reaching a minimum at 320 mg/kg for muscle malondialdehyde and 160 mg/kg for muscle liquid and water loss. The results indicated that appropriate carnosine addition could improve growth performance, muscle antioxidant capacity and flesh quality of grouper. The suitable inclusion concentration was estimated to be 195.14 mg/kg to achieve the best percent weight gain. Full article

(This article belongs to the Special Issue Growth, Metabolism, and Flesh Quality in Aquaculture Nutrition)

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16 pages, 1251 KiB

Open AccessArticle

Effects of Dietary Protein and Lipid Levels on the Growth Performance and Serum Biochemical Indices of Juvenile Furong Crucian Carp

by Zhigang He, Xing Tian, Jinlong Li, Jiarong Guo, Xiaofei Cheng and Dongwu Wang

Fishes 2024, 9(11), 466; https://doi.org/10.3390/fishes9110466 - 16 Nov 2024

Viewed by 429

Abstract

The impact of dietary protein and lipid levels on the growth performance, feed utilization, and serum biochemical indices of Furong crucian carp was examined. Five hundred and forty carp (2.35 ± 0.08 g) were randomly assigned to nine groups and fed diets with [...] Read more.

The impact of dietary protein and lipid levels on the growth performance, feed utilization, and serum biochemical indices of Furong crucian carp was examined. Five hundred and forty carp (2.35 ± 0.08 g) were randomly assigned to nine groups and fed diets with three different protein levels (30.0, 35.0, and 40.0%) and three different lipid levels (4.0, 7.0, and 10.0%) for 60 days. The current findings revealed that the interaction effect between dietary lipid and protein levels exhibited significance for the final average weight (FAW), weight gain rate (WGR), specific growth rate (SGR), feed efficiency (FE), energy deposition rate (EDR), whole-fish energy, ash, and fat content (p < 0.05). Specifically, there was a significant reduction in FAW, WGR, and SGR with increasing dietary fat supplementation. Conversely, FE, EDR, and protein efficiency ratios were significantly decreased with increasing dietary protein levels (p < 0.05). Furthermore, serum albumin and globulin levels exhibited significant increases in response to dietary lipid inclusion (p < 0.05). The findings collectively indicate that Furong crucian carp fed a diet comprising 4% lipid and 30% protein exhibited the optimal growth and feed utilization. Conversely, excessive protein and lipid supplementation were detrimental to growth and resulted in the aggravation of metabolic disorders. Full article

(This article belongs to the Special Issue Development of Low-Crop, Low-Fishmeal or Low-Fish Oil Feeds for Aquaculture)

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20 pages, 3992 KiB

Open AccessArticle

Length–Weight Relationship and Spatiotemporal Distribution Pattern of Three Schizothoracinae Fishes Along the Nujiang River in the Qinghai–Tibetan Plateau, China

by Mingdian Liu, Weitong Xu, Fengyue Zhu, Xinbin Duan, Shaoping Liu and Daqing Chen

Fishes 2024, 9(11), 465; https://doi.org/10.3390/fishes9110465 - 15 Nov 2024

Viewed by 262

Abstract

The Qinghai–Tibet Plateau (QTP) is a unique ecological area that has faced issues like diminishing ecosystem stability and increasing pressures on resources and the environment. These issues have arisen as a result of the combined impact of global warming and human activities in [...] Read more.

The Qinghai–Tibet Plateau (QTP) is a unique ecological area that has faced issues like diminishing ecosystem stability and increasing pressures on resources and the environment. These issues have arisen as a result of the combined impact of global warming and human activities in recent times. The study of the growth and distribution patterns of schizothoracinae fishes can support guiding policy decisions about the conservation of aquatic species and ecological habitats in the QTP. The investigation on fish resources was carried out in the QTP section of the Nujiang River during the spring and autumn seasons of 2017, 2018, and 2019. A total of seven sampling sites were established based on variations in elevation. According to length–weight relationship (LWR) analysis, Schizothorax nukiangensis mainly displayed a negative allometric growth while Ptychobarbus kaznakovi and Schizopygopsis thermalis mainly showed near isometric growth or positive allometric growth in the QTP section of the Nujiang River. Due to temperature and food abundance, the three schizothoracinae fishes showed better growth performance in autumn than spring. Spatial heterogeneity exhibited a greater influence on the LWR of S. nukiangensis and P. kaznakovi than seasonal variation. In contrast, seasonal variation on S. thermalis showed greater influence than spatial heterogeneity. According to the linear mixed effect model (LMM), both spatial factors and seasons had influence on fish growth in the QTP. Schizothorax nukiangensis was identified as the predominant species from CWL to BS, spanning an altitude range of 1800 to 2700 m. Ptychobarbus kaznakovi was identified as the main species at LL, BB, and BR, occupying an altitude range of 2700 to 3800 m. Schizopygopsis thermalis is primarily distributed at altitudes beyond 4000 m and along the tributary river Yuqu. Principal coordinates analysis (PCOA) and nonmetric multidimensional scaling (NMDS) divided schizothoracinae fish populations into three clusters by spatial differences. Redundancy analysis (RDA) and Monte Carlo Permutation analysis revealed that habitat elevation and water temperature had a significant impact on schizothoracinae fish distribution. This article enhances our understanding of the distribution and environmental adaptation of indigenous fish in the Qinghai–Tibet Plateau. Full article

(This article belongs to the Special Issue Adaptation and Response of Fish to Environmental Changes)

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22 pages, 9352 KiB

Open AccessArticle

Research on the Separation Technology of Kelp and Shellfish Box Based on Shellfish–Kelp Mixed Culture Mode

by Yanan Wang, Zehao Zha, Xian Wang, Yipeng Cui, Xinxin Wang, Duanyang Geng, Hua Zhou and Tongfei Sheng

Fishes 2024, 9(11), 464; https://doi.org/10.3390/fishes9110464 - 15 Nov 2024

Viewed by 240

Abstract

Aiming at the problem of floating shellfish boxes interfering with kelp harvesting when mechanized kelp harvesting is based on shellfish–kelp mixed culture mode, this paper combines the structural characteristics of the shellfish box itself, designs the kelp harvesting unit test bench and develops [...] Read more.

Aiming at the problem of floating shellfish boxes interfering with kelp harvesting when mechanized kelp harvesting is based on shellfish–kelp mixed culture mode, this paper combines the structural characteristics of the shellfish box itself, designs the kelp harvesting unit test bench and develops a shellfish box separator device. The key factors affecting the box separator’s separation effect were derived through the theoretical analysis. The process of separation of a shellfish box by the box separator is simulated and optimized under the derived boundary conditions. The single-factor test for the separating effect of the box separator was conducted with ADAMS kinematics simulation software. The test showed the optimal utility intervals for the key factors under consideration. Further orthogonal tests were conducted for the three key factors, which were ranked in descending order of importance as box separator separation angle θ, box separator taper angle β and box separator placement depth h. The optimal parameter combination is the box separator separation angle of 31°, the box separator taper angle of 30° and the box separator placement depth of 550 mm. Verification experiments have shown that both indicators, the farthest horizontal distance of the shellfish box and the angle of the shellfish box deviating from the box separator, meet the actual production requirements. In summary, the separator can effectively separate the shellfish box from the kelp, and the device is simple in design, quick in operation, and accomplished separation without disturbing shellfish. This study can provide a theoretical basis for the separation technology of kelp and shellfish box under shellfish–kelp mixed culture mode. Full article

(This article belongs to the Special Issue New Technologies for Improving Fisheries and Aquaculture Production and Management)

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13 pages, 1884 KiB

Open AccessArticle

Changes in Physiological Homeostasis in the Gills of Litopenaeus vannamei Under Carbonate Alkalinity Stress and Recovery Conditions

by Meng Xiao, Yuxiu Nan, Yukai Yang, Hua Li and Yafei Duan

Fishes 2024, 9(11), 463; https://doi.org/10.3390/fishes9110463 - 15 Nov 2024

Viewed by 300

Abstract

Carbonate alkalinity (CA) is the major toxic factor that interferes with the survival and growth of shrimp in saline–alkaline water. Gills are the main entry organ for CA toxicity in shrimp. In this study, low-salinity cultured Litopenaeus vannamei were exposed to 5 mmol/L [...] Read more.

Carbonate alkalinity (CA) is the major toxic factor that interferes with the survival and growth of shrimp in saline–alkaline water. Gills are the main entry organ for CA toxicity in shrimp. In this study, low-salinity cultured Litopenaeus vannamei were exposed to 5 mmol/L CA stress for 7 days and then recovered for 7 days to explore the physiological changes in the gills under CA stress and recovery conditions at multiple biological levels. The results showed that CA stress increased the activities of antioxidative biochemical indexes (T-AOC, T-SOD, and POD) and the relative expression levels of romo1, nrf2, and gpx genes, while it decreased the relative expression levels of the sod and hsp70 genes. In addition, CA stress also increased the relative expression levels of genes involved in endoplasmic reticulum (ER) stress (bip, ire1, and xbp1), immunity (alf, crus, pen-3 and propo), apoptosis (casp-3), detoxification metabolism (cyp450 and gst), and osmotic adjustment (ca, nka-α, nka-β, vatp, nhe, clc, aqp, tip4, and ccp). Although changes in some of the physiological indexes were reversed after the CA stress was relieved, they still could not effectively recover to the control level. These results reveal that CA stress has a negative impact on physiological homeostasis in the shrimp gills by inducing oxidation and ER stress and by interfering with immunity, apoptosis, detoxification, and osmotic adjustment. Full article

(This article belongs to the Special Issue Physiological Response Mechanisms of Aquatic Animals to Stress)

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21 pages, 3253 KiB

Open AccessArticle

Gene Expression Comparison Between the Injured Tubercule Skin of Turbot (Scophthalmus maximus) and the Scale Skin of Brill (Scophthalmus rhombus)

by João Estêvão, Andrés Blanco-Hortas, Juan A. Rubiolo, Óscar Aramburu, Carlos Fernández, Antonio Gómez-Tato, Deborah M. Power and Paulino Martínez

Fishes 2024, 9(11), 462; https://doi.org/10.3390/fishes9110462 - 14 Nov 2024

Viewed by 358

Abstract

Turbot and brill are two congeneric commercial flatfish species with striking differences in skin organization. The calcified appendages in turbot skin are conical tubercles, while in brill, they are elasmoid scales. A skin injury involving epidermal and dermal levels was evaluated 72 h [...] Read more.

Turbot and brill are two congeneric commercial flatfish species with striking differences in skin organization. The calcified appendages in turbot skin are conical tubercles, while in brill, they are elasmoid scales. A skin injury involving epidermal and dermal levels was evaluated 72 h post-injury to compare the skin regeneration processes between both species. An immune-enriched 4x44k turbot oligo-microarray was used to characterize the skin transcriptome and gene expression profiles in both species. RNA-seq was also performed on the brill samples to improve transcriptome characterization and validate the microarray results. A total of 15,854 and 12,447 expressed genes were identified, respectively, in the turbot and brill skin (10,101 shared) using the oligo-microarray (11,953 and 9629 annotated). RNA-seq enabled the identification of 11,838 genes in brill skin (11,339 annotated). Functional annotation of skin transcriptomes was similar in both species, but in turbot, it was enriched on mechanisms related to maintenance of epithelial structure, mannosidase activity, phospholipid binding, and cell membranes, while in brill, it was enriched on biological and gene regulation mechanisms, tissue development, and transferase and catalytic activities. The number of DEGs identified after skin damage in brill and turbot was 439 and 143, respectively (only 14 shared). Functions related to catabolic and metabolic processes, visual and sensorial perception, response to wounding, and wound healing were enriched in turbot DEGs, while metabolism, immune response, oxidative stress, phospholipid binding, and response to stimulus were enriched in brill. The results indicate that differences may be related to the stage of wound repair due to their different skin architecture. This work provides a foundation for future studies directed at skin defense mechanisms, with practical implications in flatfish aquaculture. Full article

(This article belongs to the Section Biology and Ecology)

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24 pages, 3229 KiB

Open AccessArticle

The Functional Response of Estuarine Fish Communities to Hydrologic Change in a Semi-Arid Ecosystem

by Lisa A. Gonzalez and Antonietta Quigg

Fishes 2024, 9(11), 461; https://doi.org/10.3390/fishes9110461 - 13 Nov 2024

Viewed by 375

Abstract

Functional assessment approaches were used to identify the responses of fish to environmental change in the San Antonio Bay System (Texas, USA). Using a 26-year coastal fisheries dataset (1993–2018), multivariate analyses revealed relationships between functional group abundance and freshwater inflows in the upper [...] Read more.

Functional assessment approaches were used to identify the responses of fish to environmental change in the San Antonio Bay System (Texas, USA). Using a 26-year coastal fisheries dataset (1993–2018), multivariate analyses revealed relationships between functional group abundance and freshwater inflows in the upper segments (Hynes Bay and Guadalupe Bay), but the patterns were decoupled from inflows in the lower bay segments (San Antonio Bay, Ayres Bay and Espiritu Santo Bay). In Hynes and Guadalupe Bays, freshwater migrant carnivores accounted for a significant fraction of the community irrespective of the gear, year or flow. Freshwater stragglers (omnivores and carnivores) were often present in the upper reaches of the bay. In the lower reaches, marine migrant omnivores were present during high and low flows in Espiritu Santos Bay, but only during low flows in Ayres Bay. Marine migrant carnivores were more important in gill nets irrespective of the flow conditions. The five most abundant fish were estuarine resident carnivores and omnivores, accounting for 53.5% of the community. Declines in the abundance of functional groups occurred during the 2011–2014 drought, with rebounds in 2015–2018. Functional methodologies provide insights into estuarine ecosystems and can serve as management tools to assess changes in fish assemblages. Full article

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18 pages, 2355 KiB

Open AccessFeature PaperArticle

Cultivation and Growth Dynamics of Capelin (Mallotus villosus) from Hatch to Adulthood

by Tómas Árnason, Birkir Bárðarson and Agnar Steinarsson

Fishes 2024, 9(11), 460; https://doi.org/10.3390/fishes9110460 - 12 Nov 2024

Viewed by 574

Abstract

This study describes the first successful rearing of capelin from hatch to adulthood in a laboratory setting using intensive culture methods. Over the span of about two years, the capelin were reared in aquaculture tanks under a constant temperature of 7 °C. The [...] Read more.

This study describes the first successful rearing of capelin from hatch to adulthood in a laboratory setting using intensive culture methods. Over the span of about two years, the capelin were reared in aquaculture tanks under a constant temperature of 7 °C. The capelin demonstrated a robust linear growth during their first year of life, with a mean length increment of 0.36 mm per day. Due to their accelerated growth, some of the capelin became sexually mature as early as one year post-hatch. The first year was characterized by a rapid increase in condition factor (CF) while the second year showed a plateau. The von Bertalanffy growth equation effectively described the two-year growth of the cultivated capelin, predicting an asymptotic length (L∞) of 18.4 cm, similar to the 18.6 cm median L∞ of wild Icelandic capelin (1981–2018 cohorts). The cultivated capelin were projected to reach this length in 2.6 years, compared to about 6 years for wild capelin. This study provides new insights into the growth dynamics of capelin and although the species is sensitive to handling, it demonstrates that intensive culture methods can be used to investigate biological aspects of this important forage species. Full article

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14 pages, 1875 KiB

Open AccessArticle

Effects of Heat Stress on the Muscle Meat Quality of Rainbow Trout

by Yalan Li, Changqing Zhou, Yong Zhang and Xingxu Zhao

Fishes 2024, 9(11), 459; https://doi.org/10.3390/fishes9110459 - 11 Nov 2024

Viewed by 563

Abstract

The effects of heat stress on aquatic animals are increasingly being discerned, but little is known about the effects of heat stress on muscle meat quality or the flavor of muscle. This study aimed to evaluate the effects of heat stress on the [...] Read more.

The effects of heat stress on aquatic animals are increasingly being discerned, but little is known about the effects of heat stress on muscle meat quality or the flavor of muscle. This study aimed to evaluate the effects of heat stress on the muscle antioxidant properties, structural and physical properties (e.g., pH, muscle color, shear force, and expressible moisture), chemical composition (e.g., nucleotides, organic acids, amino acids, and minerals), and volatile substances of rainbow trout. We observed that the antioxidant capacity of muscle decreased after stress experiments at 22.5 °C for 24 h. The content of inflammatory factors notably increased (p < 0.05), the pH value and red value of muscle decreased (p < 0.05), the interfiber space increased, and several muscle fibers were broken. Heat stress changed the contents of nucleotides, organic acids, minerals, and amino acids in muscle. The contents of IMP and AMP, which play an important role in the flavor of muscle, decreased (p < 0.05). The contents of two amino acids that provide a sweet taste decreased; those of five amino acids that provide a bitter taste increased (p < 0.05). Heat stress also affected the amount and type of volatile substances in muscle, which affected muscle odor. These results suggest that heat stress may exert adverse effects on the oxidative stability, structure, meat quality, and flavor of muscle, requiring attention and prevention. Full article

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16 pages, 13245 KiB

Open AccessArticle

Method for Non-Contact Measuring the Weight of Sturgeon in Intensive Aquaculture

by Junjie Hu, Kai Lin, Shiyu Zhang, Rui Zhang, Hongsong Li and Runqiu Xia

Fishes 2024, 9(11), 458; https://doi.org/10.3390/fishes9110458 - 10 Nov 2024

Viewed by 351

Abstract

Weight information plays a pivotal role in sturgeon breeding and production management. However, manual measurement is time consuming and labor intensive due to the immense size of the sturgeon. Due to the unique body shape of the sturgeon, traditional image segmentation algorithms struggle [...] Read more.

Weight information plays a pivotal role in sturgeon breeding and production management. However, manual measurement is time consuming and labor intensive due to the immense size of the sturgeon. Due to the unique body shape of the sturgeon, traditional image segmentation algorithms struggle to extract the necessary features from sturgeon images, which makes them unsuitable for this particular species. Moreover, accurately measuring weight in an occlusion environment is difficult. To address these challenges, an improved YOLOv5s model with a context augmentation module, focal-efficient intersection over union, and soft non-maximum suppression was proposed in this paper. To validate the model’s feasibility, the improved YOLOv5s model was first pre-trained using the sturgeon dataset, followed by further training on the occlusion dataset for segmentation tasks. Based on the phenotypic data obtained from the improved model, a multilayer perceptron method was used to estimate the sturgeon’s weight accurately. Experimental results demonstrated that the average precision of the improved YOLOv5s model reached 89.80% under occlusion conditions, and the correlation coefficient of noncontact weight measurement results reached 89.80%. The experimental results showed that the improved algorithm effectively performs segmentation of sturgeon in occlusion conditions and can accurately estimate the mass. Full article

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

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16 pages, 310 KiB

Open AccessReview

The Effectiveness of Biofloc Technology and Its Application Prospects in Sea Cucumber (Apostichopus japonicus) Aquaculture: A Review

by Haoran Xiao, Shufeng Li, Zitong Wang, Ye Tian, Qiwei Zuo, Fenglin Tian, Yongjie Wang, Chong Zhao and Jun Ding

Fishes 2024, 9(11), 457; https://doi.org/10.3390/fishes9110457 - 10 Nov 2024

Viewed by 629

Abstract

This review aims to advance the development of biofloc technology (BFT), providing more sustainable and efficient practices for the farming of the Japanese sea cucumber (Apostichopus japonicus). BFT is a sustainable aquaculture method that promotes nutrient recycling and effective carbon source [...] Read more.

This review aims to advance the development of biofloc technology (BFT), providing more sustainable and efficient practices for the farming of the Japanese sea cucumber (Apostichopus japonicus). BFT is a sustainable aquaculture method that promotes nutrient recycling and effective carbon source management, offering significant advantages such as improving water quality, enhancing growth performance, and boosting the physiological activity and disease resistance of cultured animals. In A. japonicus farming, the optimal carbon source is glucose, and the ideal carbon-to-nitrogen (C/N) ratio ranges between 15 and 20. Microbial additives, such as the Bacillus species, have been shown to enhance biofloc formation and growth, as well as the immune responses in A. japonicus. However, the technology also faces limitations, including finding suitable biofloc culture protocols that match the physiological habits of A. japonicus and potential challenges with biofloc stability under varying environmental conditions. Based on existing research, this review discusses these limitations in the farming of A. japonicus. Additionally, it compares biofloc farming models for other economically important aquatic species. By addressing these key aspects, this review offers insights to enhance BFT performance, ultimately contributing to more efficient and sustainable A. japonicus aquaculture practices. Full article

(This article belongs to the Special Issue Biofloc Technology in Aquaculture)

24 pages, 1305 KiB

Open AccessArticle

Antioxidants, ACE I Inhibitory Peptides, and Physicochemical Composition, with a Special Focus on Trace Elements and Pollutants, of SPRING Spawning Atlantic Herring (Clupea harengus) Milt and Hydrolysates for Functional Food Applications

by Miroslava R. Atanassova, Janne K. Stangeland, Simon E. Lausen, Thomas H. Dahl, Trygg Barnung and Wenche E. Larssen

Fishes 2024, 9(11), 456; https://doi.org/10.3390/fishes9110456 - 9 Nov 2024

Viewed by 439

Abstract

Norwegian spring spawning (NVG) herring milt is a raw material with high nutritional and functional values. However, its incorporation into food presents physicochemical and sensory challenges. Its high DNA content, the presence of TMA/TMAO and possibly heavy metal and/or environmental pollutants, and its [...] Read more.

Norwegian spring spawning (NVG) herring milt is a raw material with high nutritional and functional values. However, its incorporation into food presents physicochemical and sensory challenges. Its high DNA content, the presence of TMA/TMAO and possibly heavy metal and/or environmental pollutants, and its bitter taste due to amino acids or peptides requires a careful approach to food development. Hydrolysis with food-grade enzymes enable an improvement in both the functional and sensory properties of the substrate and the increased stability of the raw materials and end products. HLPC, GC-MS, and in vitro protocols were used for the characterisation of manually extracted material (sample code: HMC) and milt from a fish-filleting line from early spring/late autumn catches. Three different food-grade protein hydrolysates were prepared from these raw materials (sample codes: H1, H2, and H3) as a means to estimate their functional food development potential. Combinations of three commercial enzymatic preparations were applied, targeting specific sensory properties. Parameters related to consumer safety (e.g., the presence of heavy metals and TMA/TMAO); beneficial health effects, such as antioxidant or antihypertensive bioactivities (measured using in vitro TAC, ORAC, DPPH, and ACE I inhibitory activity assays); the presence of beneficial fatty acids and micronutrients; and the protein quality were studied. On the basis of their total amino acid compositions, freeze-dried herring milt and hydrolysates could provide high-quality protein with most of the essential amino acids and taurine. Powdered milt has a particularly high fatty acid profile of bioavailable omega-3 fatty acids (2024.06 mg/100 g docosahexaenoic acid (DHA; 22:6n-3) and 884 mg/100 g eicosapentaenoic acid (EPA; 20:5n-3)). The experimentally measured levels of arsenic (3.9 ± 1.2 mg/kg) and cadmium (0.15 ± 0.05 mg/kg) were higher than the levels of the other two heavy metals (mercury and lead). The bioactivity is concentration-dependent. Overall, this work presents complementary information for the future utilisation of C. harengus powdered milt (possibly obtained directly from a fish-filleting line) and some of its protein hydrolysates as food ingredients. Full article

(This article belongs to the Special Issue Trace Elements, Drugs, Small Compounds and Antioxidants in Fish)

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20 pages, 6057 KiB

Open AccessArticle

Ultimate Fighting Crab: Agonistic Behaviour, Dominance, and Recognition in the Edible Crab, Cancer pagurus (L.)

by Finlay James Archibald Hamilton, Jonathan David Wilkes and Kevin Scott

Fishes 2024, 9(11), 455; https://doi.org/10.3390/fishes9110455 - 9 Nov 2024

Viewed by 558

Abstract

Edible crabs (Cancer pagurus) are an economically important species for Scottish inshore fisheries, with an estimated annual landing value of GBP 16 million (2023). Research into the behaviour, particularly agonistic behaviour, of this species is currently lacking. This paper aims to [...] Read more.

Edible crabs (Cancer pagurus) are an economically important species for Scottish inshore fisheries, with an estimated annual landing value of GBP 16 million (2023). Research into the behaviour, particularly agonistic behaviour, of this species is currently lacking. This paper aims to investigate behaviour, social interactions, potential hierarchies, and the impact of claw size on the outcomes of agonistic interactions of male C. pagurus through behavioural trials and retrials. Crabs were semi-randomly assigned to pairs (based on allocated condition index rating) and introduced to one another in trial tanks. Each pair underwent two trials, 24 h apart (the “trial” and “retrial”). Analyses of video records of agonistic bouts revealed that 77% of retrials were won by the initial victors, with a significant decrease in fight time between trials and retrials. Fight time was not correlated with weapon size (claw length, height, and depth). There were no differences in weapon size of winners and losers of bouts. Winners exhibited a significantly higher frequency of aggressive and dominant behaviours (approach, aggressive contact, threat displays, and mounting), and losers exhibited higher frequencies of submissive behaviours (withdrawal, retracting limbs, and remaining motionless). These results suggest that individual behaviour may play more of a role in dominance than size or other morphometric characteristics. Full article

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20 pages, 6467 KiB

Open AccessArticle

Distribution, Occupancy, and Habitat of the Endangered Carolina Madtom: Implications for Recovery of an Endemic Stream Fish

by W. Robert Cope, Thomas J. Kwak, Tyler R. Black, Krishna Pacifici, Jennifer M. Archambault and W. Gregory Cope

Fishes 2024, 9(11), 454; https://doi.org/10.3390/fishes9110454 - 7 Nov 2024

Viewed by 644

Abstract

Endemic fish are important components of freshwater ecosystems because they contribute to biodiversity and provide vital ecological functions. The Carolina Madtom, Noturus furiosus, is a small catfish endemic to the Neuse and Tar river basins of North Carolina, USA. Three previous surveys [...] Read more.

Endemic fish are important components of freshwater ecosystems because they contribute to biodiversity and provide vital ecological functions. The Carolina Madtom, Noturus furiosus, is a small catfish endemic to the Neuse and Tar river basins of North Carolina, USA. Three previous surveys over the past 60 years have shown declining occurrence and abundance in the basins, and as such, the species was listed as federally endangered in 2021. To provide critical information to guide Carolina Madtom conservation and recovery strategies, we surveyed 36 sites (75 locations) in both basins to (1) determine the current distribution of the Carolina Madtom, (2) develop occupancy models to estimate probability of detection and occurrence of the species throughout its range, and (3) determine its instream habitat use and suitability. We collected 59 Carolina Madtom during snorkel surveys in the Tar River basin and none from the Neuse River basin, indicating that Carolina Madtom populations are still declining in both occurrence and abundance throughout their historical and recent range, especially in the Neuse River basin. Occupancy modeling estimated low occupancy probability (0.35), while detection probability was high (0.81). Carolina Madtom occupied slow-to-moderate velocity water over sand and gravel substrate, using cobble and woody debris as cover. Habitat suitability distributions quantified the most suitable ranges of microhabitat parameters for Carolina Madtom occupancy. A comparison of available suitable habitat in the two river basins revealed that adequate suitable habitat was available in both basins, suggesting that other factors such as pollution or predation from the non-native Flathead Catfish Pylodictis olivaris, may be contributing to population declines. The application of our results will aid in management and recovery actions for the species. Full article

(This article belongs to the Special Issue Biodiversity and Spatial Distribution of Fishes)

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19 pages, 12715 KiB

Open AccessArticle

Artificial Induction of Spawning in Threeline Grunt, Parapristipoma trilineatum Under Controlled Environmental Conditions

by Jin Woo Park, Jeong-Hyeon Cho, Seong Il Baek, Kang-Hee Im and Yong-Woon Ryu

Fishes 2024, 9(11), 453; https://doi.org/10.3390/fishes9110453 - 7 Nov 2024

Viewed by 405

Abstract

The threeline grunt (Parapristipoma trilineatum) is a recently introduced aquaculture species that has attracted considerable interest in Korea. However, research on its aquaculture potential and reproductive biology remains limited. This study aimed to investigate the natural reproductive cycle and the feasibility of [...] Read more.

The threeline grunt (Parapristipoma trilineatum) is a recently introduced aquaculture species that has attracted considerable interest in Korea. However, research on its aquaculture potential and reproductive biology remains limited. This study aimed to investigate the natural reproductive cycle and the feasibility of manipulating the spawning period of the threeline grunt through environmental control. We designed an environmental changes protocol involving a gradual increase in water temperature (16 °C → 21 °C) and extension of photoperiod (10 L → 14 L) from January to April and compared the group exposed to these conditions to those maintained under natural conditions. The experimental group exhibited significantly higher plasma sex steroid hormone levels at 60 and 90 days and significantly higher gonadosomatic index at 100 days. In addition, the experimental group spawned between April and June, approximately 2 months earlier than that of the control group. Despite earlier spawning, no significant differences were found in egg diameter, hatching rate, and larval notochord length. These findings suggest that spawning can be accelerated through photothermal changes without negatively impacting egg and larval quality. This study provides valuable insights into the reproductive biology of the threeline grunt and highlights the potential of utilizing photothermal control to enhance its aquaculture production. Full article

(This article belongs to the Special Issue Advances in Fish Reproductive Physiology)

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17 pages, 4733 KiB

Open AccessArticle

Transcriptomic Analysis of Non-Specific Immune Responses in the Rice Field Eel (Monopterus albus) Infected with Pallisentis (Neosentis) celatus

by Qin Lei, Xiaoling Li, Hao Wu, Yiwen Wan, Yukun Xie, Jinwei Gao, Wenwen Suo, Ming Zeng, Lingli Liu, Dongsheng Ou, Zhonggui Xie and Rui Song

Fishes 2024, 9(11), 452; https://doi.org/10.3390/fishes9110452 - 5 Nov 2024

Viewed by 520

Abstract

Parasitic infestations present significant threats to the physiological health and ecological stability of aquatic species, frequently compromising immune defenses and elevating mortality rates. This study was conducted to elucidate the non-specific immune responses induced by Pallisentis (Neosentis) celatus infection in Monopterus albus, [...] Read more.

Parasitic infestations present significant threats to the physiological health and ecological stability of aquatic species, frequently compromising immune defenses and elevating mortality rates. This study was conducted to elucidate the non-specific immune responses induced by Pallisentis (Neosentis) celatus infection in Monopterus albus, with a focus on intestinal histopathology and transcriptome gene expression. A histopathological examination revealed minor alterations in intestinal villi under low-level infection. A transcriptome analysis, performed using Illumina sequencing technology, identified 347 upregulated and 298 downregulated genes involved in critical biological pathways, such as lipid metabolism, immune responses, and the regulation of inflammatory processes. GO and KEGG analyses indicated the upregulation of immune-related pathways, including the RIG-I-like and IL-17 signaling pathways, highlighting a robust intestinal immune response. Conversely, the complement pathway was found to be downregulated, with significant suppression of C9, suggesting that the parasite may engage in immune evasion. Fluorescein-labeled C9 antibody assays confirmed reduced complement C9 levels in the infected tissues. A real-time PCR analysis identified the differential expression of eight genes, including C5, maats1, CFI, and gmnc, which were consistent with the sequencing results. These findings suggest that Pallisentis (Neosentis) celatus infection compromises intestinal health, induces inflammation, and activates non-specific immune responses in Monopterus albus. However, Pallisentis (Neosentis) celatus appears to evade the host immune response by suppressing the activation of complement components, thereby facilitating its reproductive parasitism. Full article

(This article belongs to the Special Issue Advances in Fish Pathology and Parasitology)

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20 pages, 472 KiB

Open AccessReview

Exploring Policy of Small-Scale Coastal Fisheries in China: Evolution, Challenges and Prospects

by Minsi Xiong, Zuli Wu, Guangrui Qi, Keji Jiang, Na Zhao and Wei Jiang

Fishes 2024, 9(11), 451; https://doi.org/10.3390/fishes9110451 - 4 Nov 2024

Viewed by 570

Abstract

China plays a significant role in the global fishing industry. The small-scale fisheries (SSFs) operating along its coast have made noteworthy and invaluable contributions in the areas of poverty alleviation, protein provision, social equity, and overall socioeconomic development. Coastal small-scale fishing management is [...] Read more.

China plays a significant role in the global fishing industry. The small-scale fisheries (SSFs) operating along its coast have made noteworthy and invaluable contributions in the areas of poverty alleviation, protein provision, social equity, and overall socioeconomic development. Coastal small-scale fishing management is a persistent challenge for all fishing nations, including China. In recent years, China has made significant strides in adopting scientific and refined approaches to fishery management in this sector. This paper provides an overview of the development of China’s coastal fishery management practices, including changes in policies, methods, and modes since the establishment of the People’s Republic of China (PRC) in 1949. To address these challenges, this research seeks to enhance the governance system of small-scale coastal fisheries by assessing values from three dimensions: society, economy, and ecology. Full article

(This article belongs to the Special Issue Diagnosis and Management of Small-Scale and Data-Limited Fisheries)

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3 pages, 161 KiB

Open AccessEditorial

Integrated Aquaculture and Monoculture of Low-Trophic Species

by Wagner C. Valenti and Eduardo Luis Ballester

Fishes 2024, 9(11), 450; https://doi.org/10.3390/fishes9110450 - 4 Nov 2024

Viewed by 413

Abstract

Aquaculture is undoubtedly a critical sector for satisfying the needs of a growing human population and meeting the Sustainable Development Goals of Agenda 2030 [...] Full article

(This article belongs to the Special Issue Integrated Aquaculture and Monoculture of Low-Trophic Species)

18 pages, 2834 KiB

Open AccessArticle

Toxicity of Low-Level Multiple-Mycotoxin Mixture in Nile Tilapia (Oreochromis niloticus) Is Prevented with Organically Modified Clinoptilolite Feed Additive

by Wanvisa Hussein, Konrad Wojnarowski, Paulina Cholewińska, Worrayanee Thammatorn, Natalia Szeligowska, Nemanja Todorović, Ferenc Baska, Jiraporn Rojtinnakorn and Dušan Palić

Fishes 2024, 9(11), 449; https://doi.org/10.3390/fishes9110449 - 2 Nov 2024

Viewed by 537

Abstract

Organically modified clinoptilolite (member of the zeolite family of minerals; MinazelPlus^®) feed additive, with an average weight of 30 ± 2 g, was used to prevent mycotoxicosis in Nile tilapia (Oreochromis niloticus) through its supplementation for 42 days to [...] Read more.

Organically modified clinoptilolite (member of the zeolite family of minerals; MinazelPlus^®) feed additive, with an average weight of 30 ± 2 g, was used to prevent mycotoxicosis in Nile tilapia (Oreochromis niloticus) through its supplementation for 42 days to the diet contaminated with multiple mycotoxins: aflatoxin B1 (40 µg/kg), fumonisin B1 and B2 (600 µg/kg), zearalenone (50 µg/kg), and deoxynivalenol (150 µg/kg). The fish were divided randomly into four experimental groups (basal diet control—C; fed 2 g/kg MinazelPlus^®—MZ; fed multiple mycotoxins—MT; and fed a combination of MinazelPlus^® and multiple mycotoxins—MZ + MT). Each group consisted of triplicate aquarium setups, with six fish in each replicate. Sampling was performed in weeks 2, 4, and 6. The lymphocyte count was significantly higher in the MZ group compared with the MT group and the MT + MZ group in week 6. An overall decrease in the neutrophil count was observed in the experimental groups. Histopathological analysis was performed in weeks 2 and 6, revealing significant changes in the liver, intestines, kidney, and spleen of fish from the MT group, while the MT + MZ and MZ groups were similar to the control. The addition of 2 g/kg MinazelPlus^® has the ability to prevent and reduce the adverse effects of chronic exposure to low concentrations of multiple mycotoxins in juvenile Nile tilapia. Full article

(This article belongs to the Section Nutrition and Feeding)

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13 pages, 2805 KiB

Open AccessArticle

A New Mutagenesis Tool for Songpu Mirror Carp (Cyprinus carpio L.) for Selective Breeding: Atmospheric-Pressure Room-Temperature Plasma Mutagenesis Technology

by Xiaona Jiang, Chitao Li, Mei Shang, Xuesong Hu, Yanlong Ge and Zhiying Jia

Fishes 2024, 9(11), 448; https://doi.org/10.3390/fishes9110448 - 1 Nov 2024

Viewed by 532

Abstract

As a new, safe, and efficient method, Atmospheric-Pressure Room-Temperature Plasma (ARTP) mutagenesis has been widely applied in the field of microbial breeding and industrial applications, but it is rarely used in fish. In this study, ARTP mutagenesis technology was applied for the first [...] Read more.

As a new, safe, and efficient method, Atmospheric-Pressure Room-Temperature Plasma (ARTP) mutagenesis has been widely applied in the field of microbial breeding and industrial applications, but it is rarely used in fish. In this study, ARTP mutagenesis technology was applied for the first time to a common carp strain, Songpu mirror carp (Cyprinus carpio L.), to increase genetic variation in this species. The appropriate experimental conditions were determined to include a radio frequency output power of 160 W and the processing of fertilized eggs for 360 s. The ARTP treatment group had a lower survival rate than the control group. The CV of morphological characters in the ARTP treatment group was significantly higher than that in the control group, and the CV of body weight was the highest (p < 0.05). In addition, the deformity rate in the ARTP treatment group was significantly higher than in the control group (p < 0.05). Individuals with high weight and no deformities were screened within the selection pressure of 1:15 of ARTP treatment group and fed in the same pool with the control group of the same age. The measurement of serum indices showed that, in the ARTP treatment group, TP, ALP, ALB, T-CHO, LDL levels were significantly higher than those in the control group (p < 0.05). Furthermore, the relative expressions of SOD, growth-related genes GH, IGF-I, protein synthesis-related genes TOR and 4EBP1 were significantly higher in the ARTP treatment group than in the control group (p < 0.05). In summary, Songpu mirror carp subjected to ARTP treatment showed a higher growth potential and antioxidant capacity. Full article

(This article belongs to the Special Issue Genetics and Breeding in Aquaculture)

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18 pages, 1463 KiB

Open AccessReview

Depletion Estimation, Stock–Recruitment Relationships, and Interpretation of Biomass Reference Points

by Mark N. Maunder and Kevin R. Piner

Fishes 2024, 9(11), 447; https://doi.org/10.3390/fishes9110447 - 1 Nov 2024

Viewed by 503

Abstract

Stock depletion level is an important concept in the assessment and management of exploited fish stocks because it is often used in conjunction with reference points to infer stock status. Both the depletion level and reference points can be highly dependent on the [...] Read more.

Stock depletion level is an important concept in the assessment and management of exploited fish stocks because it is often used in conjunction with reference points to infer stock status. Both the depletion level and reference points can be highly dependent on the stock–recruitment relationship. Here, we show how depletion level is estimated in stock assessment models, what data inform the depletion level, and how the stock–recruitment relationship influences the depletion level. There are a variety of data that provide information on abundance. In addition, to estimate the depletion level, unexploited absolute abundance needs to be determined. This often means extrapolating the abundance back in time to the start of the fishery, accounting for the removals and the productivity. Uncertainty in the depletion level arises because the model can account for the same removals by either estimating low productivity (e.g., low natural mortality) and high carrying capacity or high productivity and a low carrying capacity, and by estimating different relationships between productivity and depletion level, which are strongly controlled by the stock–recruitment relationship. Therefore, estimates of depletion are particularly sensitive to uncertainty in the biological processes related to natural mortality and the stock–recruitment relationship and to growth when length composition data are used. In addition, depletion-based reference points are highly dependent on the stock–recruitment relationship and need to account for recruitment variability, particularly autocorrelation, trends, and regime shifts. Future research needs to focus on estimating natural mortality, the stock–recruitment relationship, asymptotic length, shape of the selectivity curve, or management strategies that are robust to uncertainty in these parameters. Tagging studies, including close-kin mark-recapture, can address some of these issues. However, the stock–recruitment relationship will remain uncertain. Full article

(This article belongs to the Special Issue Assessment and Management of Fishery Resources)

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14 pages, 941 KiB

Open AccessArticle

Effects of Dietary Supplementation with Bacillus subtilis natto on Growth, Digestive Enzyme Activity, Immune Response, and Intestinal Microorganisms of Red Sea Bream, Pagrus major

by Yukun Zhang, Manabu Ishikawa, Shunsuke Koshio, Saichiro Yokoyama, Serge Dossou, Weilong Wang, Seok Seo, Jiayi Chen, Shuang Zheng and Xiaoxiao Zhang

Fishes 2024, 9(11), 446; https://doi.org/10.3390/fishes9110446 - 31 Oct 2024

Viewed by 724

Abstract

This study investigated the influence of dietary supplementation with Bacillus subtilis natto (BSN) on various physiological parameters in red sea bream (Pagrus major). Key areas of focus included growth performance, enzymatic activity related to digestion, blood biochemical markers, immune function, and [...] Read more.

This study investigated the influence of dietary supplementation with Bacillus subtilis natto (BSN) on various physiological parameters in red sea bream (Pagrus major). Key areas of focus included growth performance, enzymatic activity related to digestion, blood biochemical markers, immune function, and intestinal microorganisms. Fish were fed diets containing the following five levels of BSN: 0 (BN0), 1 × 10⁷ (BN1), 1 × 10⁸ (BN2), 1 × 10⁹ (BN3), and 1 × 10¹⁰ (BN4) CFU kg⁻¹ for 56 days. Fish in the BN3 and BN4 groups exhibited significantly enhanced growth performance compared to the BN0 group (p < 0.05). Additionally, the activities of amylase and protease were markedly higher in the BN3 and BN4 groups (p < 0.05), while lipase activity was significantly elevated in fish fed the BN3 diet (p < 0.05). Plasma total protein levels also showed a significant increase in the BN3 group (p < 0.05). Hematocrit values were significantly improved in the BN2, BN3, and BN4 groups (p < 0.05). The intestinal microbiota of the BN4 group revealed a significant increase in the populations of B. subtilis and Lactobacillus, along with a notable decrease in Escherichia coli, compared to all other groups (p < 0.05). The observed improvements in specific growth rate and the upregulation of growth-related gene expression further highlight the potential of BSN to enhance the growth performance of red sea bream. In conclusion, dietary supplementation with BSN at 1 × 10⁹ and 1 × 10¹⁰ CFU kg⁻¹ shows promise in improving the growth, health, and immune response of red sea bream. Full article

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18 pages, 3815 KiB

Open AccessArticle

Living Along Distribution Margins: Differences in the Body and Biochemistry of Red Squat Lobster Morphotypes (Grimothea monodon) from the Humboldt Current System

by Marco Quispe-Machaca, Maximiliano Zilleruelo, Pepe Espinoza, Gabriela Torres and Ángel Urzúa

Fishes 2024, 9(11), 445; https://doi.org/10.3390/fishes9110445 - 31 Oct 2024

Viewed by 508

Abstract

Grimothea monodon, an important fishery resource in the Humboldt Current marine ecosystem (HCE), present two contrasting morphotypes (PM, pelagic morphotype; BM, benthic morphotype). The fishery management of G. monodon is focused on understanding only fishery aspects that apply to a limited area, [...] Read more.

Grimothea monodon, an important fishery resource in the Humboldt Current marine ecosystem (HCE), present two contrasting morphotypes (PM, pelagic morphotype; BM, benthic morphotype). The fishery management of G. monodon is focused on understanding only fishery aspects that apply to a limited area, and there are currently no studies that evaluate the nutritional status of these morphotypes. This study evaluated the biological performance of PM and BM, analyzing the body (size, CL; weight, W; condition factor, Kn) and biochemical condition (glucose, G; proteins, P; lipids, L; fatty acids, FAs). The results reveal that G. monodon showed differences in CL and W between morphotypes, with higher values in BM than PM. The Kn was different between morphotypes with a tendency of isometric growth. In turn, the G contents were higher in PM than BM, while the contents of P, L, and FAs showed an opposite tendency, with higher contents recorded in BM than PM. Our findings suggest that the Kn should be included to strengthen the biological parameters and their relationships used in fishery management models. Differences in the biochemical condition between morphotypes can be considered potentially adaptive, in response to the combined effect of environmental factors that vary in the HCE. Full article

(This article belongs to the Special Issue Environmental Physiology of Aquatic Animals)

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12 pages, 2470 KiB

Open AccessArticle

Comparative Metabolomic Analysis Reveals the Impact of the Photoperiod on the Hepatopancreas of Chinese Grass Shrimp (Palaemonetes sinensis)

by Duojia Qu, Chunyan Fu, Muyu Han and Yingdong Li

Fishes 2024, 9(11), 444; https://doi.org/10.3390/fishes9110444 - 31 Oct 2024

Viewed by 466

Abstract

The photoperiod is a key environmental factor that in crustaceans influences development, feeding, and metabolism. In this study, liquid chromatography-tandem mass spectrometry was used to examine metabolic changes in Palaemonetes sinensis under different photoperiods. Our results showed that key metabolic pathways, such as [...] Read more.

The photoperiod is a key environmental factor that in crustaceans influences development, feeding, and metabolism. In this study, liquid chromatography-tandem mass spectrometry was used to examine metabolic changes in Palaemonetes sinensis under different photoperiods. Our results showed that key metabolic pathways, such as linoleic acid metabolism, axon regeneration, pyrimidine metabolism, and cortisol synthesis, were significantly altered under both constant light (24L:0D) and constant darkness (0L:24D) compared with natural light conditions. The photoperiod notably affected the digestive and metabolic functions of P. sinensis. Most metabolic pathways were downregulated under full darkness and full light conditions, suggesting that inhibition of metabolism is a potential adaptive response. Furthermore, enzyme assays revealed significant variations in trypsin, lipase, and amylase activity across different photoperiods, highlighting the profound impact of light conditions on digestive functions. These findings suggest that extreme light conditions may negatively impact the metabolic and digestive functions of P. sinensis. This study provides new insights into the adaptive mechanisms of P. sinensis in response to photoperiod changes and offers valuable information for optimizing aquaculture practices to enhance the health and growth performance of this crustacean. Full article

(This article belongs to the Special Issue Environmental Physiology of Aquatic Animals)

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11 pages, 278 KiB

Open AccessArticle

Growth, Feed Efficiency, and Health Status of Tilapia sp. Fed with New Technology Promoter Binder Fortified Diet

by Ating Yuniarti, I Made D. Mahariawan, Wahyu E. Kusuma, Bagus R. Hidayat and Anik M. Hariati

Fishes 2024, 9(11), 443; https://doi.org/10.3390/fishes9110443 - 31 Oct 2024

Viewed by 525

Abstract

Developing a sustainable feed with minimal or no fishmeal in tilapia production is a challenge to this industry. New Technology Promoter Binder (NTPB), a guanidinoacetic acid, is a nutritional supplement to enhance the energy metabolism of the muscle and brain tissue of vertebrates. [...] Read more.

Developing a sustainable feed with minimal or no fishmeal in tilapia production is a challenge to this industry. New Technology Promoter Binder (NTPB), a guanidinoacetic acid, is a nutritional supplement to enhance the energy metabolism of the muscle and brain tissue of vertebrates. This study aimed to evaluate several plant-based diet formulations with zero and minimal use of fishmeal enriched with NTPB on the growth, feed efficiency, and health status of Tilapia sp. The experimental diets in this study were conducted based on four formulations (minimum fishmeal/FM and zero fishmeal/NFM-based diets) with 0, 0.6, and 1.2 g·kg⁻¹ feed of NTPB supplementation. The research indicated that the various diets given to tilapia affected the growth performance of fish in terms of growth parameters and feed efficiency. Tilapias fed with NTPB grew better than those without NTPB in both FM- and NFM-based diets. The addition of NTPB was safe for tilapia as demonstrated in the blood glucose, urea, and creatinine levels, which were normal for healthy fish. The viscerosomatic and hepatosomatic indexes of tilapia fed with the experimental diets showed no distinct differences. Adding NTPB to tilapia diets increased the hardness and amino acid contents of the tilapia’s muscle, which would benefit consumers. Full article

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13 pages, 6946 KiB

Open AccessArticle

Antibody Preparation, Protein Expression, and Function Analysis of Cyp19a1b in Ovarian Differentiation in a Natural Triploid Teleost Qi River Crucian Carp (Carassius auratus)

by Yongjing Li, Yujiao Jin, Limin Wu and Xuejun Li

Fishes 2024, 9(11), 442; https://doi.org/10.3390/fishes9110442 - 31 Oct 2024

Viewed by 458

Abstract

Estrogen is an essential sex steroid that functions in numerous biological systems including female reproduction, neuroendocrine, vascular, skeletal, and immune systems. The synthesis of estrogen is controlled by the rate-limiting enzyme, which has been confirmed to exist in two different forms, named brain [...] Read more.

Estrogen is an essential sex steroid that functions in numerous biological systems including female reproduction, neuroendocrine, vascular, skeletal, and immune systems. The synthesis of estrogen is controlled by the rate-limiting enzyme, which has been confirmed to exist in two different forms, named brain aromatase and ovary aromatase, and encoded by cyp19a1a and cyp19a1b respectively in teleosts. However, existing studies have primarily focused on the expression and function of cyp19a1b in the brain and cyp19a1a in the gonad, the roles of cyp19a1b in the female gonad of teleosts are largely unknown. In our previous study, we cloned the full length of the cyp19a1b gene from a natural triploid teleost Qi River crucian carp (Carassius auratus), andthe spatial and temporal expression patterns of cyp19a1b mRNA were detected. To further clarify the roles of cyp19a1b in the ovarian differentiation of Qi River crucian carp, we produced a polyclonal antibody of Cyp19a1b in this study. Western blotting results showed that Cyp19a1b was mainly expressed in the brain and then in the ovary, heart, liver, and muscle. During embryogenesis, Cyp19a1b was abundantly expressed in the neurula stage. Immunohistochemistry demonstrated that Cyp19a1b was expressed in the radioactive glial cells (RGCs) of the brain from 20 days after hatching (dah) and the somatic cells of the ovaries from 30 dah, the critical period of ovarian differentiation in Qi River crucian carp. With the treatment of letrozole, an inhibitor of the aromatase, the expression of Cyp19a1b was downregulated both in the brain and gonad. Our results suggested that Cyp19a1b might be involved in the development of the nervous system and also participate in the ovarian differentiation of Qi River crucian carp. Full article

(This article belongs to the Special Issue Advances in Germplasm Resources and Genetic Breeding of Aquatic Animals)

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7 pages, 1067 KiB

Open AccessComment

Native or Overlooked Translocation? Comment on Antognazza et al. Current and Historical Genetic Variability of Native Brown Trout Populations in a Southern Alpine Ecosystem: Implications for Future Management. Fishes 2023, 8, 411

by Tommaso Righi, Andrea Splendiani, Vincenzo Caputo Barucchi and Andrea Gandolfi

Fishes 2024, 9(11), 441; https://doi.org/10.3390/fishes9110441 - 30 Oct 2024

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Abstract

The recent revision of Italian legislation on nature conservation has highlighted the pressing necessity of elucidating the native distribution range of managed species. A recent study by Antognazza et al. (Current and Historical Genetic Variability of Native Brown Trout Populations in a Southern [...] Read more.

The recent revision of Italian legislation on nature conservation has highlighted the pressing necessity of elucidating the native distribution range of managed species. A recent study by Antognazza et al. (Current and Historical Genetic Variability of Native Brown Trout Populations in a Southern Alpine Ecosystem: Implications for Future Management. Fishes 2023, 8, 411) provides insights into the native status of brown trout in the Lombardy Prealps, northern Italy, and advocates urgent conservation measures. However, the possible effect of historical and recent anthropogenic impacts was dismissed in the paper. Here, we present how human-mediated activities plausibly might contribute to the observed distribution of population genetic variation, considering both the available literature and ongoing “Mediterranean trout” stocking activities in the region. Implementing management strategies without clear scientific evidence poses significant risks to native biodiversity conservation. Full article

(This article belongs to the Section Taxonomy, Evolution, and Biogeography)

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27 pages, 2494 KiB

Open AccessArticle

Insights into Decapod Sentience: Applying the General Welfare Index (GWI) for Whiteleg Shrimp (Penaeus vannamei—Boone, 1931) Reared in Aquaculture Grow-Out Ponds

by Ana Silvia Pedrazzani, Nathieli Cozer, Murilo Henrique Quintiliano and Antonio Ostrensky

Fishes 2024, 9(11), 440; https://doi.org/10.3390/fishes9110440 - 29 Oct 2024

Viewed by 727

Abstract

The rapid growth of shrimp farming, particularly of Penaeus vannamei, accounts for about 80% of the global production of farmed shrimp and involves the cultivation of approximately 383 to 977 billion individuals annually, which highlights the urgent need to address the ethical [...] Read more.

The rapid growth of shrimp farming, particularly of Penaeus vannamei, accounts for about 80% of the global production of farmed shrimp and involves the cultivation of approximately 383 to 977 billion individuals annually, which highlights the urgent need to address the ethical and technical implications of raising potentially sentient beings. This study builds on the state-of-the-art assessment of sentience, consciousness, stress, distress, nociception, pain perception, and welfare to adapt the General Welfare Index (GWI) for farmed shrimp. The GWI is a quantitative index developed by our research group to measure the degree of welfare in aquaculture, and it has been previously applied to grass carp and tilapia. Using the PRISMA methodology and the creation of a hypothetical shrimp farm, the GWI, with 31 specific and measurable indicators across various welfare domains, is adapted to P. vannamei, offering a comprehensive assessment framework. The inclusion of quantitative welfare indicators promises to improve living conditions in alignment with legislation adopted on decapods’ sentience and contemporary scientific advances. Full article

(This article belongs to the Section Sustainable Aquaculture)

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