Fishes

34 pages, 27775 KiB

Open AccessReview

Fishes in Marine Caves

by Marcelo Kovačić, Vasilis Gerovasileiou and Robert A. Patzner

Fishes 2024, 9(6), 243; https://doi.org/10.3390/fishes9060243 - 20 Jun 2024

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Fishes in marine caves have attracted limited attention by the scientific community in comparison to subterranean fishes which have lost eyes and pigmentation. They constitute a largely unexplored component of marine fish diversity, except for the relatively well-studied marine caves of the Mediterranean [...] Read more.

Fishes in marine caves have attracted limited attention by the scientific community in comparison to subterranean fishes which have lost eyes and pigmentation. They constitute a largely unexplored component of marine fish diversity, except for the relatively well-studied marine caves of the Mediterranean Sea. These habitats are characterized by steep environmental gradients of decreasing light and decreasing water exchange. The fishes recorded so far in marine caves are not exclusive residents of this habitat and they are also present at least in the other mesolithial habitats. In the Mediterranean marine caves, 132 fishes have been recorded to date, representing about 17% of the total Mediterranean fish species richness. Most of these species are reported from the anterior cave zones where some light still exists, while a smaller number of species are known from the totally dark zones. Among them, 27.3% are accidental visitors, 53.8% are the regular mesolithial visitors and switchers between mesolithion and open water, 5.3% are permanent residents of the mesolithion, but also occur in other habitats, and 13.6% are exclusive permanent residents of mesolithion. Some mesolithial exclusive permanent residents recorded in marine caves share similar morphology, probably as adaptations to these habitats. Full article

(This article belongs to the Special Issue Behavior, Ecology and Evolution of Subterranean Fish)

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Graphical abstract

21 pages, 5041 KiB

Open AccessArticle

DDEYOLOv9: Network for Detecting and Counting Abnormal Fish Behaviors in Complex Water Environments

by Yinjia Li, Zeyuan Hu, Yixi Zhang, Jihang Liu, Wan Tu and Hong Yu

Fishes 2024, 9(6), 242; https://doi.org/10.3390/fishes9060242 - 20 Jun 2024

Viewed by 579

Abstract

Accurately detecting and counting abnormal fish behaviors in aquaculture is essential. Timely detection allows farmers to take swift action to protect fish health and prevent economic losses. This paper proposes an enhanced high-precision detection algorithm based on YOLOv9, named DDEYOLOv9, to facilitate the [...] Read more.

Accurately detecting and counting abnormal fish behaviors in aquaculture is essential. Timely detection allows farmers to take swift action to protect fish health and prevent economic losses. This paper proposes an enhanced high-precision detection algorithm based on YOLOv9, named DDEYOLOv9, to facilitate the detection and counting of abnormal fish behavior in industrial aquaculture environments. To address the lack of publicly available datasets on abnormal behavior in fish, we created the “Abnormal Behavior Dataset of Takifugu rubripes”, which includes five categories of fish behaviors. The detection algorithm was further enhanced in several key aspects. Firstly, the DRNELAN4 feature extraction module was introduced to replace the original RepNCSPELAN4 module. This change improves the model’s detection accuracy for high-density and occluded fish in complex water environments while reducing the computational cost. Secondly, the proposed DCNv4-Dyhead detection head enhances the model’s multi-scale feature learning capability, effectively recognizes various abnormal fish behaviors, and improves the computational speed. Lastly, to address the issue of sample imbalance in the abnormal fish behavior dataset, we propose EMA-SlideLoss, which enhances the model’s focus on hard samples, thereby improving the model’s robustness. The experimental results demonstrate that the DDEYOLOv9 model achieves high

P r e c i s i o n

,

R e c a l l

, and

m e a n A v e r a g e P r e c i s i o n

(

m A P

) on the “Abnormal Behavior Dataset of Takifugu rubripes”, with values of 91.7%, 90.4%, and 94.1%, respectively. Compared to the YOLOv9 model, these metrics are improved by 5.4%, 5.5%, and 5.4%, respectively. The model also achieves a running speed of 119 frames per second (

F P S

), which is 45

F P S

faster than YOLOv9. Experimental results show that the DDEYOLOv9 algorithm can accurately and efficiently identify and quantify abnormal fish behaviors in specific complex environments. Full article

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

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15 pages, 4887 KiB

Open AccessArticle

Exploring the Internal Defense System of Cerastoderma glaucum (Bruguière, 1789) Exposed to Pristine Microplastics: The Sentinel Role of Haemocytes as Biomarkers

by Alessio Alesci, Davide Di Paola, Sebastian Marino, Federica De Gaetano, Marco Albano, Silvana Morgante, Gabriele Rigano, Letterio Giuffrè, Magdalena Kotanska, Nunziacarla Spanò and Eugenia Rita Lauriano

Fishes 2024, 9(6), 241; https://doi.org/10.3390/fishes9060241 - 20 Jun 2024

Viewed by 460

Abstract

The ubiquitous presence of microplastics (MPs) in the environment is a major concern for the conservation of biodiversity. Numerous studies show the detrimental effects of MPs on marine species, especially because of their small size and their capacity to absorb organic contaminants from [...] Read more.

The ubiquitous presence of microplastics (MPs) in the environment is a major concern for the conservation of biodiversity. Numerous studies show the detrimental effects of MPs on marine species, especially because of their small size and their capacity to absorb organic contaminants from their surroundings. The bivalve mollusk Cerastoderma glaucum (Bruguière, 1789), because of its wide geographic distribution and immobile feeding habits, can be used as a sentinel and bioindicator species. By examining the presence, localization, and co-localization of Toll-like receptor 2 (TLR2) and inducible nitric oxide synthetase (iNOS), this study aims to evaluate the response of the internal defense system of C. glaucum to pristine MPs through the employment of confocal microscopy and bioinformatics techniques. The results show haemocytes immunoreactive to the antibodies tested; in particular, a higher number of TLR2-positive haemocytes can be observed in the group exposed to pristine MPs. These findings suggest that haemocytes can play a key biomarker role as sentinels to environmental pollutants. Furthermore, bioinformatics analyses on the antibodies tested confirmed an evolutionary conservation of these molecules. These data highlight the critical role of phagocytosis in identifying ecosystem damage and are helpful in develo** biosensors with less negative effects on the environments in which they are applied. Full article

(This article belongs to the Section Aquatic Invertebrates)

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12 pages, 896 KiB

Open AccessArticle

Growth, Metabolic, Hepatic and Redox Parameters, Digestive Enzymes and Innate Immunity in Mugil liza Fed a Citral-Supplemented Diet

by Natacha C. Mori, Bruna T. Michelotti, Caio C. F. Magnotti, Caroline A. Bressan, Letícia B. Bianchin, Fernando J. Sutili, Ana Paula G. Almeida, Luiz C. Kreutz, Maria A. Pavanato, Vinicius R. Cerqueira, Silvio T. da Costa, Bernardo Baldisserotto and Berta M. Heinzmann

Fishes 2024, 9(6), 240; https://doi.org/10.3390/fishes9060240 - 20 Jun 2024

Viewed by 547

Abstract

Mugil liza juveniles (6.69 ± 0.06 g) were subjected to dietary citral (0-control, 0.5, 1.0 and 2.0 mL per kg feed) for 45 days, and its possible effects on zootechnical and metabolic parameters, digestive enzymes, innate immunity, oxidative status and liver damage were [...] Read more.

Mugil liza juveniles (6.69 ± 0.06 g) were subjected to dietary citral (0-control, 0.5, 1.0 and 2.0 mL per kg feed) for 45 days, and its possible effects on zootechnical and metabolic parameters, digestive enzymes, innate immunity, oxidative status and liver damage were evaluated. At the end of the experiment, fish fed 2.0 mL citral per kg feed showed a greater weight gain and protein retention efficiency, as well as enhanced activities of pepsin (stomach) and amylase (intestine) compared with control fish. Citral supplementation decreased liver lipoperoxidation and increased the activities of glutathione peroxidase, glutathione-S-transferase and superoxide dismutase in the gills, liver and brain. The highest level of citral inclusion augmented non-protein thiol content in the brain and gills. Myeloperoxidase activity was lower in fish offered 1.0 and 2.0 mL citral per kg feed. Dietary citral did not influence the plasma levels of aspartate aminotransferase and alanine aminotransferase or the hepatic histology. As it improved growth, the activity of digestive enzymes and general health, dietary citral may be recommended for M. liza at 2.0 mL per kg feed. Full article

(This article belongs to the Special Issue Advances in Sustainable Aquaculture Production Systems)

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16 pages, 3410 KiB

Open AccessArticle

Transcriptome Analysis of Juvenile Black Rockfish Sebastes schlegelii under Air Exposure Stress

by Changlin Liu, Zheng Zhang, Shouyong Wei, Wenjie **ao, Chao Zhao, Yue Wang and Liguo Yang

Fishes 2024, 9(6), 239; https://doi.org/10.3390/fishes9060239 - 19 Jun 2024

Viewed by 508

Abstract

The study aimed to uncover the molecular response of juvenile Sebastes schlegelii to air exposure stress by identifying differentially expressed genes (DEGs) that may underlie their anti-stress mechanisms. Juvenile Sebastes schlegelii were subjected to varying durations of air exposure stress. The total RNA [...] Read more.

The study aimed to uncover the molecular response of juvenile Sebastes schlegelii to air exposure stress by identifying differentially expressed genes (DEGs) that may underlie their anti-stress mechanisms. Juvenile Sebastes schlegelii were subjected to varying durations of air exposure stress. The total RNA was extracted from whole tissues and sequenced using the Illumina NovaSeq 6000 platform. The transcriptome data were analyzed to identify DEGs through pairwise comparisons across a control group and two experimental groups exposed to air for 40 s and 2 min 30 s, respectively. The comparative DEG analysis revealed a significant number of transcripts responding to air exposure stress. Specifically, 5173 DEGs were identified in the 40 s exposure group (BS) compared to the control (BC), 6742 DEGs in the 2 min 30 s exposure group (BD) compared to the control (BC), and 2653 DEGs when comparing the BD to the BS group. Notably, Gene Ontology (GO) analysis showed an enrichment of DEGs associated with peptidase activity and extracellular regions, suggesting a role in the organism’s stress response. Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analysis pointed to the involvement of metabolic pathways, which are crucial for energy management under stress. The upregulation of protein digestion and absorption pathways may indicate a physiological adaptation to nutrient scarcity during stress. Additionally, the identification of antibiotic biosynthesis pathways implies a potential role in combating stress-induced infections or damage. The identified DEGs and enriched pathways provide insights into the complex anti-stress response mechanisms in juvenile Sebastes schlegelii. The enrichment of peptidase activity and extracellular region-related genes may reflect the initiation of tissue repair and immune response following air exposure. The connection between protein digestion and absorption pathways and anti-stress capabilities could be interpreted as a metabolic readjustment to prioritize energy-efficient processes and nutrient assimilation during stress. The role of antibiotic biosynthesis pathways suggests a defensive mechanism against oxidative stress or microbial invasion that might occur with air exposure. Full article

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

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20 pages, 3562 KiB

Open AccessArticle

Preliminary Insights on the Habitat Use and Vertical Movements of the Pelagic Stingray (Pteroplatytrygon violacea) in the Western Mediterranean Sea

by François Poisson, Jim R. Ellis and Sophy R. McCully Phillips

Fishes 2024, 9(6), 238; https://doi.org/10.3390/fishes9060238 - 18 Jun 2024

Viewed by 442

Abstract

Pelagic stingray (Pteroplatytrygon violacea) is the only species of stingray (Dasyatidae) that utilizes both pelagic and demersal habitats. It is the main bycatch species in pelagic longline fisheries targeting bluefin tuna (Thunnus thynnus) in the Gulf of Lions. In [...] Read more.

Pelagic stingray (Pteroplatytrygon violacea) is the only species of stingray (Dasyatidae) that utilizes both pelagic and demersal habitats. It is the main bycatch species in pelagic longline fisheries targeting bluefin tuna (Thunnus thynnus) in the Gulf of Lions. In the Mediterranean Sea, their stock structure, behavioural ecology and movements are unknown. For the first time in the Mediterranean, 17 individuals (39–60 cm disc width) were tagged with pop-up satellite archival transmitting tags using a novel method of tag attachment to investigate horizontal and vertical movements. The tags were attached for between two and 60 days. Between the months of July and October, pelagic stingray occupied a temperature range of 12.5–26.6 °C, and a depth range extending from the surface to 480 m. Monthly trends in catch-per-unit-effort (CPUE) of pelagic stingray peaked in August and decreased by late autumn. Pelagic stingray may aggregate on the continental shelf during summer and move southwards in early autumn, and this movement pattern is considered in relation to the reproductive cycle and overwintering. At-vessel mortality was low, but there was varying evidence of post-release mortality, indicating the need for further work. Future work and options for bycatch mitigation are also discussed. Full article

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10 pages, 3225 KiB

Open AccessCommunication

First Record of the Red Cornetfish Fistularia petimba Lacepède, 1803 from Amorgos Island (Central Aegean Sea; Greece) and a Review of Its Current Distribution in the Mediterranean Sea

by Nefeli Tsaousi and Stefanos Kalogirou

Fishes 2024, 9(6), 237; https://doi.org/10.3390/fishes9060237 - 18 Jun 2024

Viewed by 380

Abstract

The rapid spread of non-native species (NNS) poses a significant threat to biodiversity globally, with the Mediterranean region being particularly susceptible due to increased human activities and its status as a marine biodiversity hotspot. In this study, we focus on the introduction and [...] Read more.

The rapid spread of non-native species (NNS) poses a significant threat to biodiversity globally, with the Mediterranean region being particularly susceptible due to increased human activities and its status as a marine biodiversity hotspot. In this study, we focus on the introduction and distribution of Fistularia petimba, a member of the Fistulariidae family, in the eastern Mediterranean Sea and a record from the coasts of Amorgos Island, Greece. Through a baseline fishery study conducted over 12 months, utilizing experimental sampling with gillnets, trammel nets, and longlines, one individual of F. petimba was captured off the coast of Katapola Bay. Morphological examination confirmed its identity, with measurements on meristic characteristics obtained and the stomach content analysed. This finding represents a significant addition to the documented distribution of F. petimba in the Mediterranean Sea, particularly in the Aegean Sea, underscoring the importance of ongoing research in uncovering new occurrences and expanding our understanding of marine biodiversity and ecosystem changes. Further investigation into the ecological preferences and population dynamics of F. petimba in the Aegean Sea is crucial for informed conservation and management efforts if this species is considered to be established. Full article

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

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14 pages, 2726 KiB

Open AccessArticle

Transcriptional Analysis Reveals the Iron Regulation Network of the Pathogenic Yeast Metschnikowia bicuspidata in Response to Iron Stress

by Jun Liu, Songyue You, Yuting Wang, Jie Bao and Hongbo Jiang

Fishes 2024, 9(6), 236; https://doi.org/10.3390/fishes9060236 - 18 Jun 2024

Viewed by 250

Abstract

Metschnikowia bicuspidata, a globally distributed opportunistic pathogenic fungus, poses a significant threat to crustaceans in diverse aquatic ecosystems, causing severe diseases. Iron, recognized as a virulence factor, plays a crucial role in successful infection with M. bicuspidata. Therefore, this study aims to [...] Read more.

Metschnikowia bicuspidata, a globally distributed opportunistic pathogenic fungus, poses a significant threat to crustaceans in diverse aquatic ecosystems, causing severe diseases. Iron, recognized as a virulence factor, plays a crucial role in successful infection with M. bicuspidata. Therefore, this study aims to investigate the transcriptome response of M. bicuspidata to low- and high-iron conditions. Overall, 1082 differentially expressed genes (DEGs) (FDR < 0.05, |log₂FC ≥ 1.5|) were identified, comprising 977 and 105 DEGs, in response to low- and high-iron conditions, respectively. These genes predominantly participate in altering metabolism, cell membranes, or cellular structure, allowing the organism to adapt to varying iron levels. Iron limitation-induced genes play crucial roles in energy metabolism, transport, and catabolism pathways. Moreover, 27 ortholog genes were associated with iron transport and homeostasis, with 7 of them participating in iron uptake and regulation under low-iron conditions. This study contributes to the comprehension of iron homeostasis in aquatic fungi. It may offer potential therapeutic strategies for managing M. bicuspidata diseases. Full article

(This article belongs to the Special Issue Prevention and Control of Diseases in Aquaculture of Shrimp and Crab)

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24 pages, 4382 KiB

Open AccessArticle

Arginine-Vasotocin Neuronal System in Steindachneridion parahybae (Siluriformes: Pimelodidae) and Its Influence on Artificially Induced Spawning in Captivity

by Renato M. Honji, Bruno C. Araújo, Paulo H. de Mello, Martín R. Ramallo, Leonel Morandini, Danilo Caneppele and Renata G. Moreira

Fishes 2024, 9(6), 235; https://doi.org/10.3390/fishes9060235 - 18 Jun 2024

Viewed by 346

Abstract

This study summarizes new data on induced spawning of Steindachneridion parahybae, focusing on the aggressive behavior of females. This study characterizes the vasotocinergic system using immunohistochemistry, highlighting the potential influence of arginine-vasotocin (AVT) on reproductive physiology. Two experimental groups were proposed: (A) [...] Read more.

This study summarizes new data on induced spawning of Steindachneridion parahybae, focusing on the aggressive behavior of females. This study characterizes the vasotocinergic system using immunohistochemistry, highlighting the potential influence of arginine-vasotocin (AVT) on reproductive physiology. Two experimental groups were proposed: (A) control, with one female in the aquarium, and (B) experimental, with two females in the same aquarium. Dominant (D) females presented a more aggressive behavior and did not show any injury. They apparently had a length and body mass higher than injured nondominant (ND) females. The analysis identified positive AVT immunoreactive (ir) neurons exclusively within the preoptic area, including parvocellular, magnocellular, and gigantocellular subpopulations, containing fibers-ir extending into the pituitary gland. Cellular and nuclear areas were greater in D compared to ND in the magnocellular subpopulation. There were no differences between parvocellular and gigantocellular subpopulations. There was a difference on the steroid plasma profile of cortisol (more in ND than in D) and 17α,20β-dihydroxy-4-pregnen-3-one (more in D than in ND). Furthermore, control and D females presented higher optical densities for AVT-ir, gonadotropin-releasing hormone-ir, and luteinizing hormone-ir than ND. In general, there were no differences in the results of female (control group) with D females. The AVT system is highly complex, possibly counting multiple sites of action during artificial reproduction and acting directly and/or indirectly associated with behavioral and physiological changes in S. parahybae females when induced to spawning. Full article

(This article belongs to the Special Issue Reproductive Biology and Breeding of Fish)

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16 pages, 789 KiB

Open AccessArticle

Swimming Performance Assessments of Fish Species of Greatest Conservation Need to Inform Future Stream Crossing Designs in Texas

by Cameron M. Emadi, Preston T. Bean and Edward M. Mager

Fishes 2024, 9(6), 234; https://doi.org/10.3390/fishes9060234 - 18 Jun 2024

Viewed by 272

Abstract

Conventional structures associated with stream crossings such as bridges and culverts can lead to zones of high-velocity water flow that impede fish passage. Such obstacles are likely to harm native fish populations by impacting migrations critical to their life history strategies, causing habitat [...] Read more.

Conventional structures associated with stream crossings such as bridges and culverts can lead to zones of high-velocity water flow that impede fish passage. Such obstacles are likely to harm native fish populations by impacting migrations critical to their life history strategies, causing habitat fragmentation and extirpation, thereby limiting population growth and distribution. Due to the high rates of human population growth and development occurring in Texas, this is an issue of particular concern for fish designated as species of greatest conservation need (SGCN). This project focused on four SGCN fishes native to the Edwards Plateau Ecoregion, namely the Guadalupe Bass, Guadalupe Roundnose Minnow, Guadalupe Darter, and Plateau Shiner, at both adult (all species) and juvenile (Guadalupe Bass only) life stages. Our primary aim was to aid in the design of future culverts associated with stream crossings (or the modification of existing culverts) so that the water velocities through these structures do not exceed the swimming capacities of our target SGCN fishes. To this end, we assessed their maximum sustained swimming speeds (U_crit) under a typical range of Edwards Plateau stream temperatures (15, 22.5, and 30 °C) to be used in site-specific calculations of the maximum allowable culvert water velocities (Vf). A secondary objective was to collect physiological endpoints of relevance to the overall swimming performance including the maximum burst swimming speeds (U_max), metabolic rate measurements (i.e., standard metabolic rate (SMR), maximum metabolic rate (MMR), and aerobic scope (AS)), cost of transport (COT), and optimal swimming speed (U_opt). Temperature-related effects were observed that can be used to inform site-specific culvert designs. In general, the highest U_crit values for the tested species were near, or possibly between, 22.5 and 30 °C, while U_max stayed relatively consistent among treatments. Full article

(This article belongs to the Section Biology and Ecology)

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12 pages, 845 KiB

Open AccessFeature PaperArticle

Mercury Levels in the Crab Grapsus grapsus across the Galápagos Archipelago

by George D. Jackson, Christine H. Jackson, Maura Brandao, Adam K. Jackson, Eduardo Espinoza and Monica Soria-Carvajal

Fishes 2024, 9(6), 233; https://doi.org/10.3390/fishes9060233 - 18 Jun 2024

Viewed by 430

Abstract

The levels of mercury (Hg) were examined in the leg muscle of the crab Grapsus grapsus from five sites on four islands within the Galápagos archipelago. Mercury values obtained using a Milestone DMA 80 evo direct mercury analyzer varied both within and among [...] Read more.

The levels of mercury (Hg) were examined in the leg muscle of the crab Grapsus grapsus from five sites on four islands within the Galápagos archipelago. Mercury values obtained using a Milestone DMA 80 evo direct mercury analyzer varied both within and among sites. Total mercury concentrations (mg kg⁻¹ dry weight) ranged from the lowest at a protected location at Isabela Island (0.06 ± 0.02) to the highest at the San Cristóbal urban location (2.04 ± 0.069). Crabs from South Plaza Island also had surprisingly high levels of mercury with a mean of 1.2 ± 0.6. Values from urban sites at Isabela Island and Academy Bay, Santa Cruz, had intermediate values. When converted to wet weight, crabs from both San Cristóbal and South Plaza were within or above the levels (0.3–0.5 mg kg⁻¹ wet weight set by various government agencies) considered potentially harmful to human health if ingested. A lesser number of both oysters and barnacles were also analyzed for mercury at South Plaza and Academy Bay, and while the values were lower compared to the crabs, they followed the same pattern of elevated levels at South Plaza compared to Academy Bay. It is unclear as to whether the mercury comes from natural sources, such as volcanism, or anthropogenic causes. Full article

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18 pages, 2953 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

Viewed by 368

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)

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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 1666

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, **mei Liu, Binghui Mao and Baishuang Yin

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

Viewed by 432

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, 4472 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 **g 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 442

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)

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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 438

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, 1987 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-** Park, Hye ** 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 471

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)

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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 ** 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 454

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, 10738 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, **g 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 479

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, [...] Read more.

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)

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14 pages, 2353 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 285

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)

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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 507

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, 3583 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, **aomin Zhang, **uxia Wang, Wei Chen, Guangxin Cui and Tiantian Wang

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

Viewed by 275

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)

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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 669

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, **gjie Hu and Zhenmin Bao

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

Viewed by 555

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 681

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, Yue** 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 470

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 **aojie Cui, Pengxiang Xu, Tao Tian, Mingyuan Song, Xuyang Qin, Dehua Gong, Yan Wang, Xuguang Zhang, Binbin **ng, Mingzhi Li and Leiming Yin

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

Viewed by 576

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 581

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, 5587 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 554

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)

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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

Viewed by 368

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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Fishes, Volume 9, Issue 6 (June 2024) – 55 articles

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