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

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)

► Show Figures

Figure 1

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

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)

► Show Figures

Figure 1

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

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 specific growth rate. Full article

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

► Show Figures

Graphical abstract

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

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)

► Show Figures

Graphical abstract

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

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)

► Show Figures

Figure 1

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

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)

► Show Figures

Figure 1

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

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)

► Show Figures

Figure 1

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

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)

► Show Figures

Figure 1

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

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

► Show Figures

Figure 1

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

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

► Show Figures

Figure 1

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

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

► Show Figures

Figure 1

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

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)

► Show Figures

Figure 1

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

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

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)

► Show Figures

Figure 1

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

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

► Show Figures

Figure 1

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

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)

► Show Figures

Figure 1

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

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)

► Show Figures

Figure 1

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

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)

► Show Figures

Figure 1

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

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)

► Show Figures

Figure 1

Journal Description

Fishes

Latest Articles

Journal Menu

Journal Browser

Highly Accessed Articles

Latest Books

E-Mail Alert

News

Topics

Conferences

Special Issues

Topical Collections

Further Information

Guidelines

MDPI Initiatives

Follow MDPI