Fishes

18 pages, 877 KiB

Open AccessArticle

Pharmacokinetics and Withdrawal Times of Cefotaxime in White Leg Shrimp (Litopenaeus vannamei) after Oral Administration

by Thi Kim Duyen Huynh, Marie-Louise Scippo, Mathias Devreese, Siska Croubels, Quoc Thinh Nguyen, Caroline Douny, Thi Hoang Oanh Dang, Quoc Viet Le and Minh Phu Tran

Fishes 2024, 9(6), 232; https://doi.org/10.3390/fishes9060232 - 17 Jun 2024

Abstract

A high-performance liquid chromatography method coupled to tandem mass spectrometry was validated in order to study the pharmacokinetics of cefotaxime in shrimp hepatopancreases and plasma, as well as its withdrawal time related to a maximum residue limit (MRL) in shrimp muscle. Pharmacokinetics parameters [...] Read more.

A high-performance liquid chromatography method coupled to tandem mass spectrometry was validated in order to study the pharmacokinetics of cefotaxime in shrimp hepatopancreases and plasma, as well as its withdrawal time related to a maximum residue limit (MRL) in shrimp muscle. Pharmacokinetics parameters were investigated through oral medication at a single dose of 25 mg/kg shrimp body weight and subsequent hepatopancreas and plasma cefotaxime concentration measurements at 0.5, 1, 2, 4, 8, 12 and 24 h after shrimp were fed with medication. The maximum concentration of cefotaxime was observed after one hour in the hepatopancreas (C_max, 19.45 ± 2.10 mg/kg) and 4 h in plasma (0.184 ± 0.061 mg/L). Based on a minimum inhibitory concentration (MIC) of cefotaxime of 4.13 mg/L against Vibrio parahaemolyticus (known to cause acute hepatopancreatic necrosis disease (AHPND) in white leg shrimp), it was observed that the time during which the hepatopancreas cefotaxime concentration was above the MIC was 23 h. An every 24 h cefotaxime treatment could thus be effective in fighting against this bacterium in shrimp. The withdrawal time of cefotaxime was determined after shrimp were fed with medicated feed once a day and twice a day for three consecutive days. Shrimp muscle was collected on day 1 and day 3 during medication and 1, 3, 7, 14 and 21 days after medication was stopped. Considering an MRL of 50 μg/kg, the withdrawal times were 8.5 degree-days (corresponding to 6.9 h at 29.5 °C) after shrimp were fed with medicated feed once a day for 3 days and 95.5 degree-days (77.7 h at 29.5 °C) after shrimp were fed with medicated feed twice a day for 3 days. Moreover, histological analysis revealed that feeding shrimp with cefotaxime at the given dose in once- or twice-a-day treatments did not negatively impact the shrimp hepatopancreas. Full article

(This article belongs to the Special Issue Pharmacokinetic in Aquatic Animals)

9 pages, 1652 KiB

Open AccessCommunication

An Examination of the Effects of Dorsal Fin-Mounted SPOT on Carcharodon carcharias, the Great White Shark

by Grace L. Hicks and Phillip S. Lobel

Fishes 2024, 9(6), 231; https://doi.org/10.3390/fishes9060231 - 17 Jun 2024

Viewed by 282

Abstract

This opinion piece presents empirical evidence to examine possible negative consequences of the use of penetrative tagging as used on the great white shark (GWS). Tagging programs currently using this method attach SPOT (Spatial Positioning Only Tags) using corrodible bolts inserted through the [...] Read more.

This opinion piece presents empirical evidence to examine possible negative consequences of the use of penetrative tagging as used on the great white shark (GWS). Tagging programs currently using this method attach SPOT (Spatial Positioning Only Tags) using corrodible bolts inserted through the dorsal fin while the shark is taken out of water. Such methods can cause harm to the tagged individual. Possible adverse effects include impacts on growth, tag biofouling, wounds, heightened stress, and hemorrhaging. This method may adversely impact dorsal fin structure and the shark’s hydrodynamics. As a result, data collected may not be reflective of natural behavior. Bolted SPOT are semi-permanently affixed to the shark but can have a battery life of approximately 3.5 years. Most of these tags (69%) ceased transmitting in less than 2 years. Alternative tagging technologies exist as more humane options. Full article

(This article belongs to the Special Issue Elasmobranch Biodiversity, Conservation and Management)

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14 pages, 5777 KiB

Open AccessArticle

Transcriptomic Revealed That Selenium-Rich Lactobacillus plantarum Alleviated Cadmium-Induced Immune Responses in Bulatmai barbel Luciobarbus capito Kidneys

by Qingsong Sun, Yuran Pang, Yuhan Qin, Ziting Dong, Yanling Ma, Yuan Zhao, Zhanning Zhang, Jinmei Liu, Binghui Mao and Baishuang Yin

Fishes 2024, 9(6), 230; https://doi.org/10.3390/fishes9060230 - 16 Jun 2024

Viewed by 210

Abstract

Cadmium (Cd) is a common environmental pollutant that accumulates mainly in the kidneys and thus endangers the physiological health of aquatic animals. Selenium (Se) is a natural antidote to heavy metals that antagonises heavy metal toxicity and enhances the antioxidant capacity of organisms. [...] Read more.

Cadmium (Cd) is a common environmental pollutant that accumulates mainly in the kidneys and thus endangers the physiological health of aquatic animals. Selenium (Se) is a natural antidote to heavy metals that antagonises heavy metal toxicity and enhances the antioxidant capacity of organisms. Lactobacillus plantarum (L. plantarum) can reduce the toxicity of heavy metals through adsorption, reduction and metabolism. Studies have confirmed that the biological synthesis of Se nanoparticles (Bio-SeNPs) using bacterial microorganisms is simple, safe and less toxic than the synthesis of inorganic and organic Se, but the effect on Cd-induced immunosuppression is un-known. One hundred and eighty Bulatmai barbel (Luciobarbus capito: L. capito) plants were randomly divided into control (C), Cd and Cd + Se-enriched L. plantarum groups (S1L1-Cd) and fed for 28 days. The analysis methods included histopathology, test kits, transcriptomics and real-time quantitative PCR. The addition of selenium-enriched L. plantarum significantly attenuated cadmium-induced pathological changes such as glomerular atrophy, detachment of renal tubular epithelial cells, mild swelling, and interstitial inflammatory cell infiltration. Cd stress can lead to significant decreases in RBC, HCT, WBC, LZM, C3, and IgM levels, and the addition of Se-enriched L. plantarum can significantly reverse the changes in these indicators. Transcriptomic analysis revealed 488 DEGs in the Cd groups, 301 of which were upregulated and 187 of which were downregulated. There were 1474 DEGs in the S1L1-Cd group, of which 720 were upregulated and 754 were downregulated. In addition, GO enrichment analysis revealed that the biological regulation of the most differentially expressed genes involved metal ion binding, ATP binding and nucleotide inclusion. KEGG enrichment analysis revealed six of the most enriched pathways: oxidative phosphorylation, Huntington disease, retrograde endocannabinoid signalling, natural killer cell-mediated cyto-toxicity, the IL-17 signalling pathway, and leukocyte transient migration. Moreover, we selected 12 DEGs for qRT-PCR, which showed that the qRT-PCR results were consistent with our RNA-Seq results. Our results suggest that Se-enriched L. plantarum can enhance immunity and alleviate Cd exposure-mediated immunosuppression in L. capito. Full article

(This article belongs to the Section Environment and Climate Change)

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12 pages, 758 KiB

Open AccessArticle

Effects of Dietary Supplementation with Endogenous Probiotics Bacillus subtilis on Growth Performance, Immune Response and Intestinal Histomorphology of Juvenile Rainbow Trout (Oncorhynchus mykiss)

by Jing Wang, Dan Fan, Ran Zhao, Tongyan Lu, Shaowu Li and Di Wang

Fishes 2024, 9(6), 229; https://doi.org/10.3390/fishes9060229 - 15 Jun 2024

Viewed by 233

Abstract

The rainbow trout (Oncorhynchus mykiss) is an important commercial fish. Studies have shown that probiotics can promote the healthy growth of fish. In this study, we assessed the impact of an endogenous Bacillus subtilis strain (RT-BS07) on the growth, survival and [...] Read more.

The rainbow trout (Oncorhynchus mykiss) is an important commercial fish. Studies have shown that probiotics can promote the healthy growth of fish. In this study, we assessed the impact of an endogenous Bacillus subtilis strain (RT-BS07) on the growth, survival and immunological response of juvenile rainbow trout. Additionally, the morphology of rainbow trout’s intestinal tissue was measured. Control (CT) and experimental groups (B) were fed with conventional and probiotic-supplemented diets (1.0 × 10⁸ CFU per gram) for 42 days, respectively. Following feeding, a challenge experiment was carried out with Aeromonas hydrophila at 1.0 × 10⁷ CFU/mL to determine the experimental fish’s tolerance to the bacteria. The results showed that the weight gain rate (WGR) in group B was 118.2%, which was significantly higher than that in group CT (54.86%) after 42 days. The height of intestinal villi and the number of goblet cells increased in group B, thus increasing the resistance of rainbow trout to pathogenic bacteria. The alkaline phosphatase (AKP) activity (U/mg prot) in the liver, spleen and intestinal tissues of group B was significantly higher than that in the CT group. The expression of interleukin-1β (IL-1β) in the intestinal tissue of group B was 6-fold higher than that in group CT. Furthermore, the expression of growth hormone-2 (GH-2) in the spleen was 3-fold higher than that in group CT. After 12 days of A. hydrophila injection, the survival rate was 40% and 70% in group CT and group B, respectively. Collectively, the present study demonstrated that the addition of endogenous B. subtilis strain (1.0 × 10⁸ CFU per gram) to the feed can effectively promote the growth of rainbow trout and enhance immunity, which is beneficial to rainbow trout culture. Full article

(This article belongs to the Special Issue Advances in Rainbow Trout)

16 pages, 1689 KiB

Open AccessArticle

Oxidative Status of the Pyloric Caeca and Proximal Intestine in Gilthead Sea Bream Fed Diets Including Different Vegetable Oil Blends from Palm, Rapeseed and Linseed

by Irene García-Meilán, Ramon Fontanillas, Joaquim Gutiérrez, Encarnación Capilla, Isabel Navarro and Ángeles Gallardo

Fishes 2024, 9(6), 228; https://doi.org/10.3390/fishes9060228 - 14 Jun 2024

Viewed by 286

Abstract

Nowadays, including vegetable ingredients in fish diets without growth effects is common; however, their intestinal oxidative status under these conditions is less known. Five isonitrogenous and isolipidic diets with 75% vegetable oil (VO) inclusion were formulated for juvenile gilthead sea bream (Sparus [...] Read more.

Nowadays, including vegetable ingredients in fish diets without growth effects is common; however, their intestinal oxidative status under these conditions is less known. Five isonitrogenous and isolipidic diets with 75% vegetable oil (VO) inclusion were formulated for juvenile gilthead sea bream (Sparus aurata). As VO, one diet contained palm oil (diet P), another rapeseed oil (diet R), and the other three included linseed oil (L) combined with the above-mentioned VOs (named PL, RL and RPL diets). After 18 weeks, pyloric caeca (PC) and proximal intestine (PI) were analyzed for oxidative stress biomarkers, lipid peroxidation (LPO), and gene expression. Dietary linseed oil diminished the superoxide dismutase activity in both intestinal regions, catalase in PC and glutathione reductase in PI; rapeseed oil reduced the glutathione peroxidase (GPx) and glutathione-S-transferase activities in PC, and palm oil upregulated GPx activity in PI. The PL diet triggered LPO levels in the PI, and RPL-fed fish showed the highest levels of LPO in the PC due to lower antioxidant activities, while RL-fed fish presented the best oxidative status. The results suggest that the dietary amount of n-6 and the unsaturated/saturated fatty acids ratio are factors to be considered in aquafeed formulation, including VOs, to improve the intestinal oxidative status in fish. Full article

(This article belongs to the Section Nutrition and Feeding)

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12 pages, 1224 KiB

Open AccessArticle

Protective Effects of Long Double-Stranded RNA with Different CpG Motifs against Miamiensis avidus and Viral Hemorrhagic Septicemia Virus (VHSV) Infections in Olive Flounder (Paralichthys olivaceus)

by Hee-Jae Choi, Da-Yeon Choi, Jung-Jin Park, Hye Jin Jung, Bo-Seong Kim, Sung-Chul Hong, Jun-Hwan Kim and Yue Jai Kang

Fishes 2024, 9(6), 227; https://doi.org/10.3390/fishes9060227 - 13 Jun 2024

Viewed by 308

Abstract

The South Korean aquaculture industry has incurred considerable production losses due to various infectious diseases. Artificially synthesized polyinosinic–polycytidylic acid (poly I:C), structurally similar to double-stranded RNA (dsRNA) and cytidine–phosphate–guanosine oligodeoxynucleotides, can enhance immune responses and protect against diseases. Here, we investigated dsRNA molecules [...] Read more.

The South Korean aquaculture industry has incurred considerable production losses due to various infectious diseases. Artificially synthesized polyinosinic–polycytidylic acid (poly I:C), structurally similar to double-stranded RNA (dsRNA) and cytidine–phosphate–guanosine oligodeoxynucleotides, can enhance immune responses and protect against diseases. Here, we investigated dsRNA molecules with different cytidine–phosphate–guanosine (CpG) motifs (dsRNA-CpGMix) as fused agents to treat Miamiensis avidus and viral hemorrhagic septicemia virus (VHSV) infection in olive flounders. We further investigated the efficacy of specific sequence motifs in dsRNA in modulating immunostimulatory effects. Fish treated with poly I:C or dsRNA-CpGMix exhibited higher survival rates than the control group. Olive flounder leukocytes stimulated with poly I:C or dsRNA-CpGMix showed increased scuticocidal activity in the presence of inactivated immune sera. dsRNA with CpG motif sequences induced higher resistance against M. avidus and VHSV infections than dsRNA without CpG motif sequences, and the dsRNA-CpGMix group showed upregulated ISG15 or Mx compared to the dsRNA-GFP group. Thus, dsRNA containing CpG motifs can be used as effective immunostimulants to enhance resistance against viral and parasitic diseases in olive flounder. The specific sequences of the CpG motifs in dsRNA may be important for enhancing immune responses and resistance against M. avidus and VHSV infections in olive flounders. Full article

(This article belongs to the Section Fish Pathology and Parasitology)

10 pages, 3327 KiB

Open AccessArticle

Effects of Various Photoperiods and Specific Wavelengths on Retinal Changes and Oxidative Stress in the Conch Tegula rustica

by Jin Ah Song, Heung-Sik Park, Yun-Hwan Jung, Dong Mun Choi, Cheol Young Choi and Dae-Won Lee

Fishes 2024, 9(6), 226; https://doi.org/10.3390/fishes9060226 - 13 Jun 2024

Viewed by 313

Abstract

To improve aquaculture practices and husbandry of a variety of gastropods, including small conch species, it is necessary to study the physiological and endocrinological responses of nocturnal conches to light exposure. In this study, we investigated the effect of the light environment on [...] Read more.

To improve aquaculture practices and husbandry of a variety of gastropods, including small conch species, it is necessary to study the physiological and endocrinological responses of nocturnal conches to light exposure. In this study, we investigated the effect of the light environment on Tegula rustica by exposing it to contrasting light conditions and observing histological changes in the retina and oxidative stress according to photoperiod and light wavelength. We confirmed that the pigment layer was significantly thicker in the group irradiated with light for 24 h (LL), but that its thickness did not differ significantly with light wavelength. Additionally, light wavelength changes did not cause a significant change in H₂O₂ concentration until 5 days after the change in the light environment. However, a significantly higher H₂O₂ concentration was observed in the LL test group on the eighth day compared with the other experimental groups. And a significantly higher total antioxidant capacity and malondialdehyde (MDA) were observed in the LL group on the third day compared with the other experimental groups. Our results indicate that the light environment affects the reaction of conches and that continuous light has a stronger effect on the thickness of the pigment layer than the light wavelength. In addition, continuous light irradiation induces excessive ROS and causes oxidative stress. These results can also be provided as basic data for husbandry when aquaculturing gastropods. Full article

(This article belongs to the Section Aquatic Invertebrates)

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18 pages, 1966 KiB

Open AccessArticle

The Establishment of the Multi-Visual Loop-Mediated Isothermal Amplification Method for the Rapid Detection of Vibrio harveyi, Vibrio parahaemolyticus, and Singapore grouper iridovirus

by Tao Li, Ronggang Ding, Jing Zhang, Yongcan Zhou, Chunsheng Liu, Zhenjie Cao and Yun Sun

Fishes 2024, 9(6), 225; https://doi.org/10.3390/fishes9060225 - 13 Jun 2024

Viewed by 286

Abstract

Abstract: Groupers are valuable economic fish in the southern sea area of China, but the threat of disease is becoming more and more serious. Vibrio harveyi, V. parahaemolyticus, and Singapore grouper iridovirus (SGIV) are three important pathogens that cause disease [...] Read more.

Abstract: Groupers are valuable economic fish in the southern sea area of China, but the threat of disease is becoming more and more serious. Vibrio harveyi, V. parahaemolyticus, and Singapore grouper iridovirus (SGIV) are three important pathogens that cause disease in groupers, and infection with either a single one or a mix of these pathogens poses a serious threat to the healthy development of grouper culture. To enhance the rapid diagnosis and screening in the early stages, it is necessary to develop rapid detection methods of these pathogens. To simultaneously and rapidly detect the three pathogens, in this study, we utilized the TolC of V. harveyi, DNAJ of V. parahaemolyticus, and RAD2 of SGIV as the target genes and established a triple visual loop-mediated isothermal amplification (LAMP) method. This LAMP method showed a detection time as fast as 30 min and a high sensitivity of 100 fg/μL. Moreover, this method exhibited strong specificity and no cross-reaction with seven types of Vibrio and Staphylococcus aureus, as well as five common viruses in aquatic animals. Then, the LAMP products were enzymically cut, and three characteristic strips were used to identify the pathogen species. The results of the clinical trials demonstrated that the method could accurately and specifically detect V. harveyi, V. parahaemolyticus, and SGIV in grouper tissues. In summary, this study successfully established a triple visual LAMP rapid detection method for V. harveyi, V. parahaemolyticus, and SGIV. The method offers several advantages including simple equipment, easy operation, rapid reaction, high specificity, high sensitivity, and visual results. It is suitable for the early and rapid diagnosis of groupers infected with V. harveyi, V. parahaemolyticus, and SGIV, thereby providing useful technical support for further application in the large-scale disease surveillance of aquaculture animals. Full article

(This article belongs to the Special Issue Fish Diseases Diagnostics and Prevention in Aquaculture)

14 pages, 1083 KiB

Open AccessArticle

Quantitative Assessment and Analysis of Fish Behavior in Closed Systems Using Information Entropy

by Minoru Kadota, Shinsuke Torisawa and Tsutomu Takagi

Fishes 2024, 9(6), 224; https://doi.org/10.3390/fishes9060224 - 12 Jun 2024

Viewed by 185

Abstract

This study introduces a method for quantitatively assessing the complexity and predictability of fish behavior in closed systems through the application of information entropy, offering a novel lens through which to understand how fish adapt to environmental changes. Utilizing simulations rooted in a [...] Read more.

This study introduces a method for quantitatively assessing the complexity and predictability of fish behavior in closed systems through the application of information entropy, offering a novel lens through which to understand how fish adapt to environmental changes. Utilizing simulations rooted in a random walk model for fish movement, we delve into entropy fluctuations under varying environmental conditions, including responses to feeding and external stimuli. Our findings underscore the utility of information entropy in capturing the intricacies of fish behavior, particularly highlighting the synchrony in collective actions and adaptations to environmental shifts. This research not only broadens our comprehension of fish behavior but also paves the way for its application in fields like aquaculture and resource management. Through our analysis, we discovered that smaller grid sizes in simulations capture detailed local fluctuations, while larger grids elucidate general trends, pinpointing a 2.5 grid as optimal for our study. Moreover, changes in swimming speeds and behavioral adaptations during feeding were quantitatively analyzed, with results illustrating significant behavior modifications. Additionally, employing a Gaussian mixture model helped to clarify the nuanced changes in fish behavior in response to altered light conditions, demonstrating the layered complexity of fish responses to environmental stimuli. This investigation confirms the efficacy of information entropy as a robust metric for evaluating fish shoal behavior, offering a fresh methodology for ecological and environmental studies, with promising implications for sustainable management practices. Full article

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

15 pages, 2593 KiB

Open AccessArticle

Flood Pulse Effects on the Growth of Pseudoplatystoma fasciatum in the Amazon Basin

by Luciana Alves Pereira, Leandro Castello, Eric Hallerman, Edson Rubens Ferreira Rodrigues, Carolina Rodrigues da Costa Doria and Fabrice Duponchelle

Fishes 2024, 9(6), 223; https://doi.org/10.3390/fishes9060223 - 12 Jun 2024

Viewed by 302

Abstract

Fish growth is a fundamental biological process driven by a multitude of intrinsic (within-individual) and extrinsic (environmental) factors that underpin individual fitness and population dynamics. Interannual variability in river hydrology regarding the intensity and duration of floods and droughts can induce interannual variations [...] Read more.

Fish growth is a fundamental biological process driven by a multitude of intrinsic (within-individual) and extrinsic (environmental) factors that underpin individual fitness and population dynamics. Interannual variability in river hydrology regarding the intensity and duration of floods and droughts can induce interannual variations in the biotic and abiotic variables that regulate fish growth. However, the understanding of how interannual variability in river hydrology affects fish growth remains limited for most species and ecosystems. We evaluated how inter-annual hydrological variations within the Amazon River basin influence the growth of the catfish Pseudoplaystoma fasciatum. Our research questions were as follows: Do floods lead to the faster growth of P. fasciatum and droughts lead to the slower growth? And do floods and droughts affect all age classes in the same manner? We sampled 364 specimens of P. fasciatum from five sites in the Amazon basin, estimated their growth rates, and related the growth rates to indices of the intensity of floods and droughts. We fitted linear mixed-effects models to test the relationship between growth increments and hydrological indices (with F and D quantifying the intensities of floods and droughts, respectively), age as fixed effects, and basins and Fish ID as random effects. We found an inverse relationship between the increment width in the fish hard parts and hydrological indices. That is, intense floods and droughts negatively affected the growth rates. We also found that the growth of P. fasciatum was no different in years with intense and mild floods across age classes 1–5, although was different for age class 6. However, the growth of P. fasciatum was faster in years of mild droughts for all age classes. Our results showing that the growth of P. fasciatum was slower in years of intense droughts are supported by those of previous studies in the Amazon basin and elsewhere. However, our results showing for the first time that the growth of P. fasciatum is slower in years of intense flooding is the opposite of patterns found in other studies. These results thus suggest that the growth of P. fasciatum is maximized within an optimum range of hydrological conditions, where neither floods nor droughts are intense. Full article

(This article belongs to the Section Biology and Ecology)

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21 pages, 2362 KiB

Open AccessArticle

Functional Alpha and Beta Diversity of Fish Communities and Their Relationship with Environmental Factors in the Huanghe River (Yellow River) Estuary and Adjacent Seas, China

by Shaowen Li, Yufang Huang, Fan Li, Yanfen Liu, Hongliang Ma, Xiaomin Zhang, Xiuxia Wang, Wei Chen, Guangxin Cui and Tiantian Wang

Fishes 2024, 9(6), 222; https://doi.org/10.3390/fishes9060222 - 12 Jun 2024

Viewed by 155

Abstract

Fisheries and bottom seawater data were collected in July in 2022 and 2023 from 15 sampling stations in the Huanghe River estuary and adjacent seas in China. The patterns of functional alpha and beta diversity of fish communities in this area and their [...] Read more.

Fisheries and bottom seawater data were collected in July in 2022 and 2023 from 15 sampling stations in the Huanghe River estuary and adjacent seas in China. The patterns of functional alpha and beta diversity of fish communities in this area and their relationships with environmental factors were studied using trait-based analysis. Five functional classifications, which included 16 functional traits, four functional alpha diversity indices (functional richness, functional evenness, functional divergence, and community-weighted mean), three functional beta diversity indices (functional beta diversity and its turnover and nestedness components), and 14 bottom environmental factors were considered. The dominant traits of fish communities were the following: benthivorous feeding habits, small and front-facing mouths, high trophic level, demersal, anguilliform, low growth coefficient, medium resilience, low vulnerability, and adapted to warm temperate conditions. The dominant migration traits and types of fish eggs varied by year, and fish abundance was the main factor affecting the dominant traits of the communities. The results of multiple regression on distance matrices and variance partitioning analysis indicated that ammonia nitrogen content, total phosphorus content, and pH were the main environmental factors that affected fish functional diversity. The N/P ratio had a bottom-up control effect on fish functional diversity. Our findings also revealed that high pH gradients and distant geographical distances can inhibit trait turnover in fish communities. Full article

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

21 pages, 6841 KiB

Open AccessArticle

Contemporary Trends in the Spatial Extent of Common Riverine Fish Species in Australia’s Murray–Darling Basin

by Wayne Robinson, John Koehn and Mark Lintermans

Fishes 2024, 9(6), 221; https://doi.org/10.3390/fishes9060221 - 12 Jun 2024

Viewed by 312

Abstract

As one of the world’s most regulated river basins, the semi-arid Murray–Darling Basin (MDB) in south-eastern Australia is considered at high ecological risk, with substantial declines in native fish populations already identified and climate change threats looming. This places great importance on the [...] Read more.

As one of the world’s most regulated river basins, the semi-arid Murray–Darling Basin (MDB) in south-eastern Australia is considered at high ecological risk, with substantial declines in native fish populations already identified and climate change threats looming. This places great importance on the collection and use of data to document population trends over large spatial extents, inform management decisions, and provide baselines from which change can be measured. We used two medium-term data sets (10 MDB basin-wide fish surveys from 2004–2022) covering the 23 catchments and 68 sub-catchments of the MDB to investigate trends in the distribution of common riverine species at the entire basin scale. Fifteen native species were analysed for changes in their contemporary range, and whilst short-term changes were identified, all species showed no significant continuous trend over the study period. We further analysed the native species extent relative to their historic records, with bony herring and golden perch occurring in 78% and 68% of their historic river kilometres, respectively, whereas southern pygmy perch, northern river blackfish, silver perch, mountain galaxias, and freshwater catfish were all estimated to occur in less than 10% of their historic extent. Six established non-native species were also analysed and were very consistent in extent over the years, suggesting that they are near the available limits of expansion of their invasion. We provide effect sizes for the spatial extent index which can be used as baselines for future studies, especially those aiming to monitor changes in the spatial extent and population status of native species, or changes in the spatial extent of new or existing non-native species. Full article

(This article belongs to the Special Issue Biomonitoring and Conservation of Freshwater & Marine Fishes)

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22 pages, 1542 KiB

Open AccessReview

Harnessing Hue: Advances and Applications of Fish Skin Pigmentation Genetics in Aquaculture

by Jialong Liu, Miaomiao Yin, Zhi Ye, Jingjie Hu and Zhenmin Bao

Fishes 2024, 9(6), 220; https://doi.org/10.3390/fishes9060220 - 10 Jun 2024

Viewed by 386

Abstract

Fish exhibit a broad spectrum of colors and patterns facilitated by specialized cells known as chromatophores. The vibrant coloration of fish, controlled by complex genetic and environmental interactions, serves critical roles in ecological functions such as mating, predation, and camouflage. This diversity not [...] Read more.

Fish exhibit a broad spectrum of colors and patterns facilitated by specialized cells known as chromatophores. The vibrant coloration of fish, controlled by complex genetic and environmental interactions, serves critical roles in ecological functions such as mating, predation, and camouflage. This diversity not only makes fish an invaluable model for exploring the molecular mechanisms of pigmentation but also significantly impacts their economic value within the aquaculture industry, where color traits can drive marketability and breeding choices. This review delves into the sophisticated biological processes governing fish pigmentation and discusses their applications in enhancing aquaculture practices. By exploring the intersection of genetic regulation, environmental influences, and advanced breeding techniques, this review highlights both the scientific understanding and practical applications of fish coloration, providing a bridge between basic biological research and its application in commercial aquaculture. Full article

(This article belongs to the Special Issue Genetic Breeding and Developmental Biology of Aquaculture Animals)

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15 pages, 727 KiB

Open AccessArticle

Evaluating the Use of Grape Pomace in Cyprinus carpio Nutrition: Effects on Growth, Biochemistry, Meat Quality, Microbiota, and Oxidative Status

by Cristian-Alin Barbacariu, Lenuța Dîrvariu, Dana Andreea Șerban, Cristina Mihaela Rîmbu, Cristina Elena Horhogea, Gabriela Dumitru, Elena Todirașcu-Ciornea, Constantin Lungoci and Marian Burducea

Fishes 2024, 9(6), 219; https://doi.org/10.3390/fishes9060219 - 7 Jun 2024

Viewed by 533

Abstract

This study investigated the effects of incorporating grape pomace (GP) into fish diets on the growth performance, physiological parameters, and biochemical composition of carp (Cyprinus carpio L.). A total of 180 carp, with an average initial weight of 65 g, were reared [...] Read more.

This study investigated the effects of incorporating grape pomace (GP) into fish diets on the growth performance, physiological parameters, and biochemical composition of carp (Cyprinus carpio L.). A total of 180 carp, with an average initial weight of 65 g, were reared in a recirculating aquaculture system (RAS). They were divided into a control group (C), fed with a diet containing 0% GP, and two experimental groups (V1 and V2), fed with diets containing 5% and 10% GP, respectively. The experiment lasted for eight weeks. Results revealed that most growth parameters were not significantly affected by GP inclusion, except for a notable difference in the hepatosomatic index (HSI), indicating an impact on liver size relative to body weight. The biochemical analysis of carp meat showed significant differences in moisture, protein, fat, collagen, and salt content between the control and experimental groups. Furthermore, the oxidative status assessment indicated that GP supplementation modulates oxidative stress and lipid peroxidation pathways in carp, enhancing their antioxidant defenses and overall health. Microbiological examination of the carp intestinal content showed that GP inclusion in fish diets influenced microbial parameters, particularly affecting the abundance of aerobic germs and Enterobacteriaceae. Full article

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16 pages, 5151 KiB

Open AccessArticle

Blood-Chemistry Parameters Comparison among Different Age Stages of Chinese Sturgeon Acipenser sinensis

by Zhaowen Chen, Yueping Zheng, Kaile Ji, Yueyong Shang, Youji Wang and Menghong Hu

Fishes 2024, 9(6), 218; https://doi.org/10.3390/fishes9060218 - 7 Jun 2024

Viewed by 358

Abstract

The Chinese sturgeon (Acipenser sinensis), a critically endangered migratory fish native to the Yangtze River estuary, is experiencing alarming population declines. Understanding the physiological and biochemical profiles of this species is paramount for its conservation. However, due to limited sample availability, blood [...] Read more.

The Chinese sturgeon (Acipenser sinensis), a critically endangered migratory fish native to the Yangtze River estuary, is experiencing alarming population declines. Understanding the physiological and biochemical profiles of this species is paramount for its conservation. However, due to limited sample availability, blood biochemical parameters have remained understudied. In this study, we examined blood chemistry in artificially cultured Chinese sturgeon ranging from 2 to 15 years of age. Our results revealed age-related trends: total protein (TP), albumin (ALB), globulin (GLO), total cholesterol (CHOL), high-density lipoprotein (HDL), low-density lipoprotein (LDL), estrogen (E₂), testosterone (T), testosterone undecanoate (11-KT), and red blood cell count (RBC) increased with age, while glucose (GLU), uric acid (UA), and serum creatinine (CREA) decreased. Levels of C-reactive protein (CRP) declined from 3 to 7 years but rose from 8 to 15 years. Blood parameters showed stabilization with age, indicating enhanced resilience and immunity. Significant alterations in parameters at ages 2–3 and 14–15 suggest critical developmental stages. These findings are crucial for understanding sturgeon growth, development, migration, and reproduction, underscoring the necessity for targeted conservation efforts during pivotal life stages. Full article

(This article belongs to the Section Physiology and Biochemistry)

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13 pages, 2663 KiB

Open AccessArticle

Frequency-Specific Responses: The Impact of an Acoustic Stimulus on Behavioral and Physiological Indices in Large Yellow Croaker

by Xiaojie Cui, Pengxiang Xu, Tao Tian, Mingyuan Song, Xuyang Qin, Dehua Gong, Yan Wang, Xuguang Zhang, Binbin Xing, Mingzhi Li and Leiming Yin

Fishes 2024, 9(6), 217; https://doi.org/10.3390/fishes9060217 - 7 Jun 2024

Viewed by 407

Abstract

This study assessed the impact of an acoustic stimulus on the behavioral responses and physiological states of the large yellow croaker (Larimichthys crocea). The test fish, with an average body weight of approximately 352.81 ± 70.99 g, were exposed to one [...] Read more.

This study assessed the impact of an acoustic stimulus on the behavioral responses and physiological states of the large yellow croaker (Larimichthys crocea). The test fish, with an average body weight of approximately 352.81 ± 70.99 g, were exposed to one hour of acoustic stimulation at seven different frequencies: 100 Hz, 125 Hz, 160 Hz, 200 Hz, 500 Hz, 630 Hz, and 800 Hz. The aim was to delineate the specific effects of acoustic stimulation on the behavior and physiological indices. The results show that acoustic stimulation significantly altered the behavioral patterns of the large yellow croaker, predominantly manifested as avoidance behavior towards the sound source. At a stimulus frequency of 630 Hz, the test fish exhibited continuous irregular motion and erratic swimming. Physiologically, one hour of exposure to acoustic stimulation notably affected the endocrine system. The levels of Epinephrine and thyroxine were significantly elevated at 200 Hz, while the cortisol levels did not show significant differences. Additionally, the lactic acid content significantly increased at 800 Hz, and the blood glucose content peaked at 630 Hz. This study discovered that sound frequencies of 200 Hz, 630 Hz, and 800 Hz led to a significant increase in the levels of Epinephrine, glucose, thyroid hormones, and lactate in large yellow croaker, consequently affecting their behavior. The changes in these physiological indicators reflect the stress response of the large yellow croaker in specific sonic environments, providing crucial insights into the physiological and behavioral responses of fish to acoustic stimuli. Full article

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

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13 pages, 1698 KiB

Open AccessArticle

Poststocking Behavior and Survival of Large Yearling Muskellunge (Esox masquinongy) in Two Northern Iowa Natural Lakes

by Jonathan R. Meerbeek

Fishes 2024, 9(6), 216; https://doi.org/10.3390/fishes9060216 - 6 Jun 2024

Viewed by 292

Abstract

Muskellunge are commonly stocked to maintain populations throughout much of North America. Poststocking survival is variable, and many jurisdictions are experimenting with stocking Muskellunge at advanced life stages (e.g., yearlings) or sizes to promote more consistent recruitment within populations. Yet, little is known [...] Read more.

Muskellunge are commonly stocked to maintain populations throughout much of North America. Poststocking survival is variable, and many jurisdictions are experimenting with stocking Muskellunge at advanced life stages (e.g., yearlings) or sizes to promote more consistent recruitment within populations. Yet, little is known about short-term poststocking behavior or survival of Muskellunge in natural lakes or if stocking larger fish results in improved poststocking survival. Radiotelemetry was used to evaluate the behavior and survival of large (mean of 418 mm; standard error of 3.4) spring-stocked yearling Muskellunge in two northern Iowa natural lakes of varying biotic and abiotic complexity. Hatchery-reared Muskellunge were fitted with radio transmitters (n = 10–15 fish/lake), stocked in each lake with conspecifics, and tracked either daily or weekly up to 112 days poststocking. Telemetry data were used to evaluate dispersal and movement, depth and vegetation use, proximity to shore, and survival. In both lakes, fish dispersed rapidly from each stocking site. Movement among lakes was similar and peaked during the first week poststocking and declined thereafter. Muskellunge were frequently located in offshore habitats in both lakes, but both depth and vegetation use varied among lakes and weeks poststocking, with Muskellunge found in deeper, more vegetated habitats in the larger, more complex natural lake. Muskellunge in both systems had high poststocking survival (86.7–90.0%). The results of this study provide managers with more information regarding yearling Muskellunge poststocking behavior and survival and indicate that larger fish may be a suitable alternative for fisheries where high poststocking mortality may be acting as a bottleneck for maintaining quality Muskellunge fisheries. Full article

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17 pages, 744 KiB

Open AccessArticle

DNA Barcoding Revealed Mislabeling of Imported Seafood Products in Thailand

by Deep Nithun Senathipathi, Soottawat Benjakul, Phutthipong Sukkapat, Matsapume Detcharoen, Gururaj Moorthy and Jirakrit Saetang

Fishes 2024, 9(6), 215; https://doi.org/10.3390/fishes9060215 - 5 Jun 2024

Viewed by 382

Abstract

Seafood mislabeling threatens customer rights and causes economic loss worldwide. The information on seafood misrepresentation in Thailand is still lacking, and the investigation and monitoring program must be well established. This study investigated the mislabeling status of imported seafood in Thailand using the [...] Read more.

Seafood mislabeling threatens customer rights and causes economic loss worldwide. The information on seafood misrepresentation in Thailand is still lacking, and the investigation and monitoring program must be well established. This study investigated the mislabeling status of imported seafood in Thailand using the DNA barcoding technique. A total of 45 imported seafood products from five distributors were included. Scientific, common, local, and market names of seafood samples were obtained from FAO and Fishbase databases. DNA was extracted, and PCR was performed using a universal primer targeting the COI gene. Species of each sample were identified with over 98% similarity based on COI sequence analysis. DNA sequence revealed 11 mislabeled samples. Among substituted species, Pangasianodon hypophthalmus and Thunnus maccoyii were found to be endangered species according to IUCN status. Products obtained from Brand-C showed the highest mislabeling rate (42.85%). The phylogenetic analysis adopted with the TIM2+F+I+G4 model showed the sequenced DNA similar to the NCBI database reference sequence. Overall, mislabeled products of imported seafood were found at the rate of 24.44%, suggesting that strict surveillance for seafood substitution should be implemented in Thailand. Full article

(This article belongs to the Special Issue Trends and Advances in Seafood Quality: Processing, Preservation and Safety Processes to Guarantee Food Value)

12 pages, 2253 KiB

Open AccessArticle

Dazl and dnd Identify Both Embryonic and Gonadal Germ Cells in Chinese Hook Snout Carp (Opsariichthys bidens)

by Zifeng Yin, Lingzhan Xue, Peng Song, Muhammad Jawad, Cong Xu, Weishao Bu and Mingyou Li

Fishes 2024, 9(6), 214; https://doi.org/10.3390/fishes9060214 - 5 Jun 2024

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Abstract

In recent years, the Chinese hook snout carp (Opsariichthys bidens) is becoming increasingly popular due to its high nutritional value and delicious taste. However, anthropogenic influences have caused a rapid reduction in its population. Considering long-term development sustainability, it is essential [...] Read more.

In recent years, the Chinese hook snout carp (Opsariichthys bidens) is becoming increasingly popular due to its high nutritional value and delicious taste. However, anthropogenic influences have caused a rapid reduction in its population. Considering long-term development sustainability, it is essential to conduct research on its reproductive development. In this study, the germ-cell related genes dazl (Obdazl) and dnd (Obdnd) were cloned, and their expression patterns were revealed. RT-PCR analysis indicated that Obdazl and Obdnd were specifically expressed in gonads. In the testis, Obdazl and Obdnd RNAs have a similar expression pattern: their transcripts were abundant in spermatogonia, gradually decreased, and eventually disappeared during spermatogenesis. Early oocytes in the ovary exhibited strong expression of Obdazl and Obdnd RNAs and reduced remarkably after peak expression at III oocytes. Surprisingly, Obdazl RNA was dynamically found in perinuclear spots that finally aggregated into the Balbiani body (Bb) in the early oocytes. Moreover, Obdazl 3′ UTR enabled the reporter gene to be expressed stably in medaka PGCs, suggesting that dazl was identified as the germ cell marker in O. bidens, which may provide perspectives for further studies on the development of PGCs in the future. Full article

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11 pages, 3252 KiB

Open AccessCommunication

Morphological Development and DNA Barcoding Identification of Pholis fangi Larvae and Juveniles in the Yellow Sea

by Shouhai Liu, Haijing Zhang, Xiao Ji, Xiaojia Peng, Yutao Qin and Weimin Yao

Fishes 2024, 9(6), 213; https://doi.org/10.3390/fishes9060213 - 3 Jun 2024

Viewed by 211

Abstract

Pholis fangi is a small, bottom-dwelling fish species endemic to the Yellow Sea and Bohai Sea in China. While previous research has focused on its population biology and molecular structure, little is known about the early developmental stages of this species. In this [...] Read more.

Pholis fangi is a small, bottom-dwelling fish species endemic to the Yellow Sea and Bohai Sea in China. While previous research has focused on its population biology and molecular structure, little is known about the early developmental stages of this species. In this study, larval and juvenile P. fangi specimens were collected from the Sheyang Sea Area, Jiangsu Province, in 2017. Morphological features were examined using microscopy, and DNA barcoding was conducted to confirm species identification. The research documented detailed changes in yolk sac, fin development, and melanophore distribution patterns across larval and juvenile stages of P. fangi. Comparative analysis with other Pholis species revealed that melanophore distribution is a key distinguishing characteristic, allowing effective differentiation between larval and juvenile stages, as well as between Pholis species. This study provides valuable insights into the early life history of P. fangi, contributing to a better understanding of the genus Pholis. The findings demonstrate the utility of combining traditional morphological observation and molecular techniques for accurate species identification, particularly during the critical larval and juvenile developmental phases. Full article

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17 pages, 4522 KiB

Open AccessArticle

The Zootechnical Performance, Health State Modulation, Morphology, and Intestinal Microbiome of Nile Tilapia Juveniles Fed with a Functional Blend of Immunostimulants Associated with a Diet High in Soybean Meal

by Lúvia Souza de Sá, Gabriela Tomas Jerônimo, Thiago Soligo, Eduardo Yamashita, Débora Machado Fracalossi, Maurício Laterça Martins and José Luiz Pedreira Mouriño

Fishes 2024, 9(6), 212; https://doi.org/10.3390/fishes9060212 - 3 Jun 2024

Viewed by 167

Abstract

The aim of this study was to evaluate the effect of supplementing feed with a functional mixture of immunomodulators, including β-glucans, nucleotides, ascorbic acid, and alpha-tocopherol, associated with a diet with lower levels of animal protein (11.5%) and higher levels of soybean meal [...] Read more.

The aim of this study was to evaluate the effect of supplementing feed with a functional mixture of immunomodulators, including β-glucans, nucleotides, ascorbic acid, and alpha-tocopherol, associated with a diet with lower levels of animal protein (11.5%) and higher levels of soybean meal (43.5%), on the zootechnical performance, health, hematological and immunological parameters, intestinal morphology, centesimal composition, and intestinal microbiome of juvenile Nile tilapia (initial weight 1.88 g ± 0.25 g, mean ± standard deviation). Two isocaloric and isoproteic diets (35% crude protein) were formulated, one with the inclusion of the immunostimulant functional mixture (40 kg·t⁻¹), composed of 150 mg·kg⁻¹ of nucleotides, 1000 mg·kg⁻¹ of β-glucans, 1000 mg·kg⁻¹ of ascorbic acid (vitamin C), and 20 mg·kg⁻¹ of alpha-tocopherol (vitamin E), and another without. The combined supplementation of nucleotides, β-glucans, ascorbic acid, and alpha-tocopherol resulted in a 59.95% increase in final weight, 64% weight gain, 66% daily gain, a 21.31% decrease in feed conversion rate, and double the retention of body protein. Supplementation also improved intestinal morphology and modulated the intestinal microbiome, increasing Chao-1 diversity. Transmission electron microscopy confirmed that fish fed with both diets exhibited intact intestinal mucosal membranes. Supplementation did not alter the hematological and immunological parameters, suggesting that there was no overstimulation of the fish’s immune system. This work allows us to evaluate the effect of reducing the use of animal protein in the diets of fish, along with the effects of nucleotides, β-glucans, ascorbic acid, and alpha-tocopherol. Together, these compounds can provide fish with the necessary tools to achieve optimal health and growth. Full article

(This article belongs to the Special Issue Relationship between Nutrition and the Immune Response of Fish)

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16 pages, 3344 KiB

Open AccessArticle

Compatibilities of Cyprinus carpio with Varied Colors of Robotic Fish

by Xiaoshuang Huang, Ying Zhang, Xinjun Chen, Xianghong Kong, Bilin Liu and Shuxia Jiang

Fishes 2024, 9(6), 211; https://doi.org/10.3390/fishes9060211 - 3 Jun 2024

Viewed by 231

Abstract

Visual selection plays a fundamental role in various aspects of animal behavior, such as colony formation, maintenance, defense, and courtship. This study investigated the effect of bionic robot fish color on carp behavior based on physiological characteristics that were observed during behavioral experiments. [...] Read more.

Visual selection plays a fundamental role in various aspects of animal behavior, such as colony formation, maintenance, defense, and courtship. This study investigated the effect of bionic robot fish color on carp behavior based on physiological characteristics that were observed during behavioral experiments. Through computer image processing and analysis of light attenuation, we observed changes in the number and positioning of carp with bionic robotic fish of different colors (white, red, blue, green, and yellow). The results indicated that (1) the attenuation coefficient of visible light in freshwater was red > yellow > green > blue; (2) the order of the average change in the number of carp responding to different colors of robotic fish was white > red > green > yellow > blue, and carp were more sensitive and responsive to white and red robotic fish; and (3) the order of the distances between different colors of robotic fish and carp was white < yellow < blue < green < red, and white and yellow robotic fish were more attractive to carp. Therefore, the use of white or yellow robotic fish for relevant operations can reduce disturbance to fish schools. Full article

(This article belongs to the Section Fishery Facilities, Equipment, and Information Technology)

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12 pages, 1717 KiB

Open AccessArticle

The Effects of Different Concentrations of Hydrogen−Rich Water on the Growth Performance, Digestive Ability, Antioxidant Capacity, Glucose Metabolism Pathway, mTOR Signaling Pathway, and Gut Microbiota of Largemouth Bass (Micropterus salmoides)

by Yin Yuan, Huixiang Li, Songwei Chen, Yongchun Lin, Jiangyuan Peng, Junru Hu and Yongsheng Wang

Fishes 2024, 9(6), 210; https://doi.org/10.3390/fishes9060210 - 1 Jun 2024

Viewed by 229

Abstract

Hydrogen−rich water (HRW) is widely recognized for its growth promoting, antioxidant, and anti−inflammatory properties. However, little is known about the role of HRW in aquaculture. This study aims to investigate how different concentrations of HRW affect the growth performance, digestive ability, antioxidant capacity, [...] Read more.

Hydrogen−rich water (HRW) is widely recognized for its growth promoting, antioxidant, and anti−inflammatory properties. However, little is known about the role of HRW in aquaculture. This study aims to investigate how different concentrations of HRW affect the growth performance, digestive ability, antioxidant capacity, mTOR signaling pathway, and gut microbiota of juvenile largemouth bass. We randomly assigned 360 fish (13.73 ± 0.1 g) to three treatments. The control group was maintained in regular water, while the treatment groups were treated with different concentrations of H₂ dissolved in water, which were H1 (179.65 ± 31.95 ppb) and H2 (280.65 ± 64.43 ppb), respectively. Through an analysis of the three treatments, it was found that H1 significantly increased the final body weight, weight gain rate, specific growth rate, and survival rate, and reduced the feed conversion ratio (p < 0.05). In addition, the trypsin activity was significantly increased in the intestine (p < 0.05), and the expression of genes related to the glucose metabolism (pk and pepck) and mTOR (tor, akt, s6k1, 4ebp1, and ampka) signaling pathways were significantly increased in the liver in H1 (p < 0.05). The relative abundance of Blautia in the gut microbiota (p < 0.05) was significantly increased in H1. Therefore, these results indicated that H1 can significantly improve growth performance, promote intestinal digestion, activate the glucose metabolism pathway and mTOR signaling pathway, and increase the abundance of beneficial bacteria in the gut of largemouth bass. These findings provided valuable support for the application of HRW to support the healthy aquaculture of largemouth bass. Full article

(This article belongs to the Section Physiology and Biochemistry)

18 pages, 3401 KiB

Open AccessArticle

Environmental Influences on Illex argentinus Trawling Grounds in the Southwest Atlantic High Seas

by Delong Xiang, Yang Li, Keji Jiang, Haibin Han, Yuhan Wang, Shenglong Yang, Heng Zhang and Yuyan Sun

Fishes 2024, 9(6), 209; https://doi.org/10.3390/fishes9060209 - 1 Jun 2024

Viewed by 208

Abstract

To understand the spatial temporal distribution characteristics of Illex argentinus caught by trawl fishing vessels in the Southwestern Atlantic Ocean and their relationship with key marine environmental factors, this study analyzed the temporal and spatial changes in the fishing ground center of trawl [...] Read more.

To understand the spatial temporal distribution characteristics of Illex argentinus caught by trawl fishing vessels in the Southwestern Atlantic Ocean and their relationship with key marine environmental factors, this study analyzed the temporal and spatial changes in the fishing ground center of trawl vessels at the ten-day scale from December 2019 to May 2022, combining Chinese trawl fishing log data marine environmental data with satellite remote sensing marine environmental data. Utilizing the Maxent model, ten-day intervals were used as the temporal scale, and ten marine environmental factors, including sea surface temperature, sea surface height, sea surface salinity, chlorophyll concentration, temperature at 50 m and 100 m depth, and the meridional and zonal velocities of ocean currents were quantitatively analyzed to explore the correlation between the spatial distribution of catch and environmental factors. The study reveals that the trawl fishing grounds for Illex argentinus are divided into southern and northern grounds. The southern grounds first appear near 45°20′ S in December, gradually moving southeastward in February and March. The northern grounds do not appear until April, near 42° S in the high seas. On the ten-day time scale, the central fishing grounds of Illex argentinus show significant spatial variability but minor interannual differences. The Maxent model results indicate that sea surface temperature and chlorophyll a concentration are the key environmental factors influencing the spatial and temporal variability of the high seas trawl fishing grounds for most of the time, with high environmental contribution rates during the fishing season. While the range of suitable habitats with an HSI > 0.6 identified by the Maxent model varies significantly between years, a pattern is observed where the range expands at the start and end of the fishing season and contracts during the peak fishing season. This suggests that a more concentrated range of suitable habitats is conducive to accurate predictions of trawl fishing grounds, enabling efficient fishing operations. Full article

(This article belongs to the Section Biology and Ecology)

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17 pages, 2268 KiB

Open AccessReview

Tropical Shrimp Biofloc Aquaculture within Greenhouses in the Mediterranean: Preconditions, Perspectives, and a Prototype Description

by Dimitrios K. Papadopoulos, Maria V. Alvanou, Athanasios Lattos, Kosmas Ouroulis and Ioannis A. Giantsis

Fishes 2024, 9(6), 208; https://doi.org/10.3390/fishes9060208 - 1 Jun 2024

Viewed by 336

Abstract

Biofloc technology (BFT) offers an innovative eco-friendly approach that is particularly applicable in shrimp farming. Penaeus vannamei is the most important seafood species in terms of global economic value. Nevertheless, its increasing global demand highlights the necessity for sustainable production of P. vannamei [...] Read more.

Biofloc technology (BFT) offers an innovative eco-friendly approach that is particularly applicable in shrimp farming. Penaeus vannamei is the most important seafood species in terms of global economic value. Nevertheless, its increasing global demand highlights the necessity for sustainable production of P. vannamei shrimps outside their native range, assuring the avoidance of genetic pollution risk. Towards this direction, the present study focuses on the feasibility of tropical shrimp species aquaculture in indoor systems evaluating BFT application in temperate zones. The achievability of P. vannamei cultivation inside greenhouses in temperate latitudes is thoroughly examined and a representative experimental biofloc setup for P. vannamei within a greenhouse in Northern Greece is demonstrated. Nevertheless, there are two major limitations, related to economy and ecology, namely the energy demand for high seawater temperature and the fact that most reared shrimps are non-indigenous species setting risk for genetic pollution, respectively. To overcome the former, energy-saving measures such as tank and greenhouse insulation in combination with a microclimate chamber construction were implemented to optimize water temperature at minimal cost. Concerning the latter, there is clear evidence that P. vannamei populations cannot be established in the Mediterranean, setting aside any environmental risk. Overall, based on the developed and tested pilot prototype, employment of optimal management practices, innovative manufacturing and clean energy alternatives, and the utilization of ecosystem services could reduce the environmental impact and maximize the profitability of biofloc operations. These actions could probably permit sustainable and economically viable farming of P. vannamei employing BFT within greenhouses in the Mediterranean. Full article

(This article belongs to the Special Issue Advances in Shrimp Aquaculture)

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14 pages, 2023 KiB

Open AccessArticle

Influence of Feeding, Temperature and Photoperiod on Purple Sea Urchin (Paracentrotus lividus) Gonad Development

by João Araújo, Margarida Gamboa, Ioannis Choulis, Ana Candeias-Mendes, Elsa Cabrita, Pedro Pousão-Ferreira and Florbela Soares

Fishes 2024, 9(6), 207; https://doi.org/10.3390/fishes9060207 (registering DOI) - 1 Jun 2024

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Abstract

Understanding and controlling reproductive cycles and gonad maturation in cultivated species are crucial in aquaculture. The sea urchin Paracentrotus lividus, known for its edible gonads, requires careful maturation control for both reproduction and commercialization. This study explores the impact of temperature, photoperiod, [...] Read more.

Understanding and controlling reproductive cycles and gonad maturation in cultivated species are crucial in aquaculture. The sea urchin Paracentrotus lividus, known for its edible gonads, requires careful maturation control for both reproduction and commercialization. This study explores the impact of temperature, photoperiod, and diet on gonad development to enhance year-round aquaculture practices. Using two independent cultivation systems, we manipulated environmental conditions to mimic different seasons. Sea urchins were exposed to natural or manipulated temperature and photoperiod conditions and fed either natural (Ulva spp.) or formulated diets. The gonadosomatic index (GI) and histological analysis were used to assess gonad development. The results revealed a clear correlation between environmental conditions, diet, and gonad maturation. Manipulated conditions accelerated maturation, with sea urchins showing advanced stages compared to natural conditions. Furthermore, sea urchins fed formulated diets exhibited higher GI values, indicating enhanced maturation. Histological analysis confirmed accelerated maturation, particularly in females. This study underscores the feasibility of controlling gonad maturation through environmental manipulation and diet, enabling year-round marketable gonad production. Providing formulated diets rich in polyunsaturated fatty acids, notably docosahexaenoic acid (DHA), enhances the commercial value of sea urchins. These findings optimize aquaculture practices for P. lividus, highlighting its adaptability to the maximal production of gonads throughout the year. Full article

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19 pages, 4100 KiB

Open AccessArticle

Research on Measuring the Bodies of Underwater Fish with Inclined Positions Using the YOLOv8 Model and a Line-Laser System

by Jiakang Li, Shengmao Zhang, Penglong Li, Yang Dai and Zuli Wu

Fishes 2024, 9(6), 206; https://doi.org/10.3390/fishes9060206 - 1 Jun 2024

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Abstract

Fish body measurement is essential for monitoring fish farming and evaluating growth. Non-destructive underwater measurements play a significant role in aquaculture management. This study involved annotating images of fish in aquaculture settings and utilized a line laser for underwater distance calibration and fish [...] Read more.

Fish body measurement is essential for monitoring fish farming and evaluating growth. Non-destructive underwater measurements play a significant role in aquaculture management. This study involved annotating images of fish in aquaculture settings and utilized a line laser for underwater distance calibration and fish body inclined-angle calculation. The YOLOv8 model was employed for fish identification and key-point detection, enabling the determination of actual body dimensions through a mathematical model. The results show a root-mean-square error of 6.8 pixels for underwater distance calibration using the line laser. The pre-training YOLOv8-n, with its lower parameter counts and higher MAP values, proved more effective for fish identification and key-point detection, considering speed and accuracy. Average body length measurements within 1.5 m of the camera showed a minor deviation of 2.46% compared to manual measurements. The average relative errors for body length and width were 2.46% and 5.11%, respectively, with corresponding average absolute errors. This study introduces innovative techniques for fish body measurement in aquaculture, promoting the digitization and informatization of aquaculture processes. Full article

(This article belongs to the Special Issue AI and Fisheries)

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20 pages, 712 KiB

Open AccessFeature PaperArticle

Feed Additives Based on N. gaditana and A. platensis Blend Improve Quality Parameters of Aquacultured Gilthead Seabream (Sparus aurata) Fresh Fillets

by María Isabel Sáez, Alba Galafat, Silvana Teresa Tapia Paniagua, Juan Antonio Martos-Sitcha, Francisco Javier Alarcón-López and Tomás Francisco Martínez Moya

Fishes 2024, 9(6), 205; https://doi.org/10.3390/fishes9060205 - 31 May 2024

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Abstract

The aim of this research is to explore the potential effects of two microalgae-based additives included in finishing feeds on the quality and shelf-life of seabream fillets. In a 41-day feeding trial, seabream specimens were fed with experimental aquafeeds containing 10% of the [...] Read more.

The aim of this research is to explore the potential effects of two microalgae-based additives included in finishing feeds on the quality and shelf-life of seabream fillets. In a 41-day feeding trial, seabream specimens were fed with experimental aquafeeds containing 10% of the bioactive supplements. These additives consisted of a blend of Nannochloropsis gaditana and Arthrospira platensis biomass, which was utilized as either raw (LB-CB) or enzymatically hydrolyzed (LB-CBplus). A control group received a microalgae-free diet. The results showed that the functional aquafeeds improved the nutritional profile of seabream fillets, increasing protein and PUFA-n3 contents while reducing the atherogenic index, especially for the LB-CBplus treatment. LB-CBplus also enhanced the texture parameters (hardness and chewiness) of fillets during the initial 5 days under cold storage. Regarding skin pigmentation, fillets showed increased greenish and yellowish coloration compared to control fish, mostly attributed to the inclusion of crude algal biomass (LB-CB). Moreover, diets enriched with microalgae additives effectively delayed muscle lipid oxidation processes under refrigeration for up to 12 days, with LB-CBplus exhibiting higher antioxidant effects. These findings highlight the potential of microalgae-based additives to enhance both the nutritional and organoleptic quality of seabream fillets. Full article

(This article belongs to the Special Issue Effects of Feed Additives on Fish Health and Fillet Quality)

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21 pages, 3320 KiB

Open AccessArticle

Feature Selection for Explaining Yellowfin Tuna Catch per Unit Effort Using Least Absolute Shrinkage and Selection Operator Regression

by Ling Yang and Weifeng Zhou

Fishes 2024, 9(6), 204; https://doi.org/10.3390/fishes9060204 - 30 May 2024

Viewed by 254

Abstract

To accurately identify the key features influencing the fisheries distribution of Pacific yellowfin tuna, this study analyzed data from 43 longline fishing vessels operated from 2008 to 2019. These vessels operated in the Pacific Ocean region (0° to 30° S; 110° E to [...] Read more.

To accurately identify the key features influencing the fisheries distribution of Pacific yellowfin tuna, this study analyzed data from 43 longline fishing vessels operated from 2008 to 2019. These vessels operated in the Pacific Ocean region (0° to 30° S; 110° E to 170° W), with a specific focus on 25 features of yellowfin tuna derived from marine environment data. For this purpose, this study opted for the Lasso regression analysis method to select features to predict Pacific yellowfin tuna fishing grounds, exploring the relationship between the catch per unit effort (CPUE) of yellowfin tuna and multiple features. This study reveals that latitude and water temperature at various depths, particularly the sea surface temperature of the preceding and subsequent months and the temperature at depths between 300 and 450 m, are the most significant features influencing CPUE. Additionally, chlorophyll concentration and large-scale climate indices (ONI and NPGIO) also have a notable impact on the distribution of CPUE for yellowfin tuna. Lasso regression effectively identifies features that are significantly correlated with the CPUE of yellowfin tuna, thereby demonstrating superior fit and predictive accuracy in comparison with other models. It provides a suitable methodological approach for selecting fishing ground features of yellowfin tuna in the Pacific Ocean. Full article

(This article belongs to the Special Issue AI and Fisheries)

13 pages, 7452 KiB

Open AccessArticle

Exploring Cellular Dynamics in the Goldfish Bulbus Arteriosus: A Multifaceted Perspective

by Doaa M. Mokhtar, Enas A. Abd-Elhafez, Marco Albano, Giacomo Zaccone and Manal T. Hussein

Fishes 2024, 9(6), 203; https://doi.org/10.3390/fishes9060203 - 29 May 2024

Viewed by 269

Abstract

The bulbus arteriosus of goldfish, Carassius auratus, possesses unique structural features. The wall of the bulbus arteriosus is exceptionally thick, with an inner surface characterized by longitudinally arranged finger-like ridges, resulting in an uneven luminal appearance. These ridges are covered by endocardium [...] Read more.

The bulbus arteriosus of goldfish, Carassius auratus, possesses unique structural features. The wall of the bulbus arteriosus is exceptionally thick, with an inner surface characterized by longitudinally arranged finger-like ridges, resulting in an uneven luminal appearance. These ridges are covered by endocardium and encased in an amorphous extracellular matrix. The inner surface of the bulbus arteriosus also contains rodlet cells at different developmental stages, often clustered beneath the endothelium lining the bulbar lumen. Ruptured rodlet cells release their contents via a holocrine secretion process. The high abundance of rodlet cells in the bulbus arteriosus suggests that this is the site of origin for these cells. Within the middle layer of the bulbus arteriosus, smooth muscle cells, branched telocytes (TCs), and collagen bundles coexist. TCs and their telopodes form complex connections within a dense collagen matrix, extending to rodlet cells and macrophages. Moreover, the endothelium makes direct contact with telopodes. The endocardial cells within the bulbus arteriosus display irregular, stellate shapes and numerous cell processes that establish direct contact with TCs. TEM reveals that they contain moderately dense bodies and membrane-bound vacuoles, suggesting a secretory activity. TCs exhibit robust secretory activity, evident from their telopodes containing numerous secretory vesicles. Furthermore, TCs release excretory vesicles containing bioactive molecules into the extracellular matrix, which strengthens evidence for telocytes as promising candidates for cellular therapies and regeneration in various heart pathologies. Full article

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Fishes, Volume 9, Issue 6 (June 2024) – 44 articles

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