Fishes

14 pages, 3904 KiB

Open AccessArticle

Isolation, Characterization, and Pathogenicity of an Aeromonas veronii Strain Causing Disease in Rhinogobio ventralis

by Xingbing Wu, Baolin Cheng, Mingyang Xue, Nan Jiang, Xuemei Li, Xiaona Hu, Xiaoli Li, Tingbing Zhu, Yongjiu Zhu and Yong Zhou

Fishes 2024, 9(5), 188; https://doi.org/10.3390/fishes9050188 - 18 May 2024

Viewed by 1294

Abstract

Rhinogobio ventralis is a rare fish found in the Yangtze River in China and has significant ecological and economic value. In this study, a bacterial strain (RV-JZ01) was isolated from the livers of diseased R. ventralis. This isolate was identified as Aeromonas [...] Read more.

Rhinogobio ventralis is a rare fish found in the Yangtze River in China and has significant ecological and economic value. In this study, a bacterial strain (RV-JZ01) was isolated from the livers of diseased R. ventralis. This isolate was identified as Aeromonas veronii based on its morphology, biochemical features and 16S rDNA phylogenetic analysis. The artificial infection of healthy R. ventralis (16 ± 2 cm) with RV-JZ01 resulted in the manifestation of clinical symptoms, in accordance with those of naturally infected fish. The 50% lethal dose (LD₅₀) of RV-JZ01 for R. ventralis was 6.3 × 10⁶ CFU/mL. Histopathological examination revealed various pathological changes in the diseased fish, including intestinal villus swelling and rupture, hepatocyte vacuolization, renal tubular cell nuclear enlargement and pyknosis, and myocardial fiber fracture and atrophy. RV-JZ01 infection significantly reduced the gut flora diversity of R. ventralis, with the relative abundances of Firmicutes and Fusobacteria increasing, and those of the Proteobacteria and Bacteroidetes decreasing. The abundance of Lactobacillus and Streptococcus dramatically increased, and the abundance of Clostridium and Escherichia reduced in the intestinal microbiota of R. ventralis infected with RV-JZ01. Antibiotic sensitivity testing revealed that RV-JZ01 was highly susceptible to 12 antimicrobials, including erythromycin, cefalexin, norfloxacin, furazolidone, sulfonamides, enrofloxacin, doxycycline, piperacillin, florfenicol, gentamicin, and lincomycin. These results contribute to the understanding of pathological alterations in R. ventralis following A. veronii infection, offering valuable data to support the implementation of disease treatment. Full article

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

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20 pages, 4392 KiB

Open AccessArticle

Merits of Multi-Indicator Precautionary Approach Management in a Male-Only Crab Fishery

by Darrell Mullowney, Krista Baker, Julia Pantin, William Coffey, Kyle Lefort and Katie Morrissey

Fishes 2024, 9(5), 187; https://doi.org/10.3390/fishes9050187 - 18 May 2024

Cited by 1 | Viewed by 807

Abstract

Snow crab replaced groundfish fisheries as the primary focus of the Newfoundland and Labrador (NL) fishing industry in the mid-1990s. Over the past three decades, management philosophies in this male-only fishery have shifted from promoting industry expansion to promoting industry rationalization to implementing [...] Read more.

Snow crab replaced groundfish fisheries as the primary focus of the Newfoundland and Labrador (NL) fishing industry in the mid-1990s. Over the past three decades, management philosophies in this male-only fishery have shifted from promoting industry expansion to promoting industry rationalization to implementing Precautionary Approach (PA) management. Until the mid-2010s, there were regionalized management strategies characterized by higher exploitation rates in northern than southern sub-stock units along the NL marine shelves. However, in the late 2010s, exploitation rates were permitted to elevate to high levels across the entire stock range in association with a large resource decline, and evidence of biological harm through fishing emerged in chronically depleted areas. In 2019, when stock and fishery productivity were near historical lows, a multi-indicator PA system was informally introduced into the management of the resource. This event coincided with anticipated improvements in stock and fishery performance. This paper examines the extent to which the multi-indicator PA management system, focused on the promotion of both biological protection and maximization of fishing efficiency, may have contributed to recent improvements in stock and fishery status. A suite of indicators from areas implementing PA guidance into management in 2019 prior to the formal adoption of the PA system in 2023 suggest the system has been highly beneficial in promoting rapid recovery and improving stock and fishery performance metrics to levels matching or exceeding historical levels under similar conditions. We discuss the capacity of the system to better safeguard biological aspects of resource and fisheries productivity moving forward under a scenario of an expectant resource decline. Full article

(This article belongs to the Special Issue Advances in Crab Fisheries)

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11 pages, 2949 KiB

Open AccessCommunication

Occurrence of Four Freshwater Stingrays (Chondrichthyes: Potamotrygoninae) in the Uatumã River Basin, Amazon Region: A Field Study

by Maria Fernanda S. Gomes, Paulo Henrique R. Aride, Maiko Willas S. Ribeiro, Cristiane C. Guimarães, Tiago C. Nóbrega, Rayana M. Paixão, Adriene Núzia A. Santos and Adriano Teixeira de Oliveira

Fishes 2024, 9(5), 186; https://doi.org/10.3390/fishes9050186 - 17 May 2024

Cited by 1 | Viewed by 1301

Abstract

The Amazon region has the largest diversity of freshwater stingrays; however, there are still places where information about this group is scarce. The present work aims to record the occurrence of freshwater stingrays in the Uatumã river basin, Amazonas, Brazil. For this, collections [...] Read more.

The Amazon region has the largest diversity of freshwater stingrays; however, there are still places where information about this group is scarce. The present work aims to record the occurrence of freshwater stingrays in the Uatumã river basin, Amazonas, Brazil. For this, collections were carried out in three municipalities bathed by the Uatumã River, Presidente Figueiredo, Itapiranga, and São Sebastião do Uatumã. The rays were collected through fishing using a hand net and, after capture, were identified through the pattern of the dorsal and ventral color of the disc, the absence or presence of the labial groove, and the organization of the row of spines on the tail, and were also measured, weighed, and sexed. In total, 69 specimens of Potamotrygonines were captured, 59 of which were from the genus Potamotrygon and ten individuals from the genus Paratrygon. The present study provides preliminary information on the characteristics of freshwater stingray species that may occur in the Uatumã River. Furthermore, new research is necessary to improve the identification of specimens to determine the diversity and elucidate aspects related to the biology of elasmobranchs in the Uatumã River Basin, Brazil. Full article

(This article belongs to the Section Biology and Ecology)

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21 pages, 3976 KiB

Open AccessFeature PaperArticle

Light Intensity of Phosphorescent-Netting Pots and Determining Their Visibility to Snow Crab (Chionoecetes opilio) Using Visual Modeling Techniques

by Colin Frank, Shannon Bayse, Rioghnach Steiner and Pierre-Paul Bitton

Fishes 2024, 9(5), 185; https://doi.org/10.3390/fishes9050185 - 17 May 2024

Viewed by 1280

Abstract

This study explores the visibility of phosphorescent-netting pots to snow crab (Chionoecetes opilio) using visual modeling techniques. Light emitted from such pots increases catch per unit effort, yet little is understood about the factors driving these higher catch rates. In this [...] Read more.

This study explores the visibility of phosphorescent-netting pots to snow crab (Chionoecetes opilio) using visual modeling techniques. Light emitted from such pots increases catch per unit effort, yet little is understood about the factors driving these higher catch rates. In this study, we measure pot light emission and snow crab visual acuity. Combining these data with estimates obtained in the literature for other biotic and abiotic factors, we model snow crab vision in relation to the pots. Utilizing these factors and environmental conditions, we derive a contrast ratio between the pot light and the ambient light. Findings reveal that the visibility of pot lights at 200-m depth depends primarily on solar angle (time of day) and time elapsed post-deployment. Additional factors influencing the vision of the pots include water column quality and benthic boundary layer turbidity. This study is the first to model the visual ecology of snow crab and the first to estimate snow crab visual acuity. These insights into snow crab visual ecology can potentially enhance fishing techniques, promote catch efficiency and sustainability, and help provide a path forward for visual ecology research in the fisheries science field. Full article

(This article belongs to the Special Issue Advances in Crab Fisheries)

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16 pages, 5922 KiB

Open AccessArticle

Comparative Analysis of Enzymatic Activities and Transcriptional Profiles of Various Hepatic Enzymes between Male and Female Yellowfin Tuna (Thunnus albacares)

by Dongge Liu, Hao Yang, Shuisheng Li, Hai Huang, Guangli Li and Huapu Chen

Fishes 2024, 9(5), 184; https://doi.org/10.3390/fishes9050184 - 17 May 2024

Cited by 2 | Viewed by 1262

Abstract

Yellowfin tuna (Thunnus albacares) is a valuable pelagic migratory fish with potential for aquaculture. Despite this, there is limited understanding of the biological and physiological characteristics of this species, particularly regarding sex differences in growth performance. The liver, a crucial organ [...] Read more.

Yellowfin tuna (Thunnus albacares) is a valuable pelagic migratory fish with potential for aquaculture. Despite this, there is limited understanding of the biological and physiological characteristics of this species, particularly regarding sex differences in growth performance. The liver, a crucial organ for digestion and metabolism, plays a significant role in regulating fish growth. This study aimed to compare liver enzyme activities and transcriptome profiles between female and male yellowfin tuna to uncover the molecular mechanisms underlying difference between the sexes. The results revealed that female yellowfin tuna exhibited higher amylase and lipid metabolism enzyme activities, while male yellowfin tuna showed higher glucose-6-phosphate dehydrogenase and antioxidant enzyme activities. Additionally, through Illumina sequencing technology, the study generated 37.74 Gb of clean data and identified 36,482 unique genes (UniGenes) in the liver transcriptome. A total of 2542 differentially expressed genes were found, with enriched Gene Ontology terms and pathways related to metabolic processes, particularly lipid metabolism and transport. These findings suggest that female yellowfin tuna have superior digestive enzyme activities and lipid metabolism, while male yellowfin tuna excel in sugar metabolism, ATP production, and antioxidant defense. This study provides valuable insights into sex differences in yellowfin tuna and could aid in advancing full-cycle aquaculture practices for this species. Full article

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

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16 pages, 2532 KiB

Open AccessArticle

Stocking Density and Diet of Two Oyster (Crassostrea gasar and Crassostrea gigas) Seeds in Fluidized Bed Bottle Nursery System

by Simone Sühnel, Francisco José Lagreze-Squella, Gabriel Nandi Corrêa, Jaqueline Araújo, Glauber de Souza, João Paulo Ramos Ferreira, Francisco Carlos da Silva, Carlos Henrique Araújo de Miranda Gomes and Claudio Manoel Rodrigues de Melo

Fishes 2024, 9(5), 183; https://doi.org/10.3390/fishes9050183 - 17 May 2024

Viewed by 938

Abstract

Crassostrea is the most farmed oyster genus worldwide and has significant economic and social impacts with environmental benefits. Hatchery oyster seed production is a highly costly phase, and a fluidized nursery system can help reduce this cost and reduce seed production time. The [...] Read more.

Crassostrea is the most farmed oyster genus worldwide and has significant economic and social impacts with environmental benefits. Hatchery oyster seed production is a highly costly phase, and a fluidized nursery system can help reduce this cost and reduce seed production time. The present study evaluated the survival and growth of two oyster species (Crassostrea gasar and Crassostrea gigas) in a fluidized bed bottle nursery system. With C. gasar, two experiments were performed; one tested three stocking densities and the other three bialgae diets. With C. gigas, one experiment with a bialgae and monoalgae in an initial bottle occupation of 8.8% produced more seeds per bottle, but an initial bottle occupation of 2.2% produced bigger seeds. Also, the experiment with C. gasar and with C. gigas tested diets did not affect seed survival, but the diets with bialgae I. galbana and N. oculate promoted more seed growth. The fluidized bed bottle nursery system developed for this study was adequate for the seeds of the oysters C. gasar and C. gigas in the nursery phase. Full article

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

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14 pages, 7508 KiB

Open AccessArticle

Calmodulin Gene of Blunt Snout Bream (Megalobrama amblycephala): Molecular Characterization and Differential Expression after Aeromonas hydrophila and Cadmium Challenges

by Jinwei Gao, Hao Wu, Xing Tian, Jiayu Wu, Min Xie, Zhenzhen Xiong, Dongsheng Ou, Zhonggui Xie and Rui Song

Fishes 2024, 9(5), 182; https://doi.org/10.3390/fishes9050182 - 16 May 2024

Viewed by 1159

Abstract

Calmodulin (Calm), a crucial Ca²⁺ sensor, plays an important role in calcium-dependent signal transduction cascades. However, the expression and the relevance of Calm in stress and immune response have not been characterized in Megalobrama amblycephala. In this study, we identified the [...] Read more.

Calmodulin (Calm), a crucial Ca²⁺ sensor, plays an important role in calcium-dependent signal transduction cascades. However, the expression and the relevance of Calm in stress and immune response have not been characterized in Megalobrama amblycephala. In this study, we identified the full-length cDNA of Calm (termed MaCalm) in blunt snout bream M. amblycephala, and analyzed MaCalm expression patterns in response to cadmium and Aeromonas hydrophila challenges. MaCalm was 1603 bp long, including a 5′-terminal untranslated region (UTR) of 97 bp, a 3′-terminal UTR of 1056 bp and an open reading frame (ORF) of 450 bp encoding a polypeptide of 149 amino acids with a calculated molecular weight (MW) of 16.84 kDa and an isoelectric point (pI) of 4.09. Usually, MaCalm contains four conservative EF hand motifs. The phylogenetic tree analysis indicated that the nucleotide sequence of MaCalm specifically clustered with Ctenopharyngodon idella with high identity (98.33%). Tissue distribution analysis demonstrated that the ubiquitous expression of MaCalm mRNA was found in all tested tissues, with the highest expression in the brain and the lowest expression in muscle. MaCalm showed significant upregulation at 14 d and 28 d post exposure to varying concentrations of cadmium in the liver; HSP70 transcripts in the liver significantly upregulated at 14 d post exposure to different concentrations of cadmium. Moreover, in response to the A. hydrophila challenge in vivo, MaCalm transcripts in the liver first increased and then decreased, but MaCalm transcripts in the kidney declined gradually with prolonged infection. After the A. hydrophila challenge, the expression level of HSP70 was significantly downregulated at 24 h in the liver and its expression level was notably downregulated at 12 h and at 24 h in the kidney. Collectively, our results suggest that MaCalm possesses vital roles in stress and immune response in M. amblycephala. Full article

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

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11 pages, 2013 KiB

Open AccessFeature PaperArticle

Thermal Tolerance of Larval Flannelmouth Sucker Catostomus latipinnis Acclimated to Three Temperatures

by Tawni B. Riepe, Zachary E. Hooley-Underwood and Megan Johnson

Fishes 2024, 9(5), 181; https://doi.org/10.3390/fishes9050181 - 16 May 2024

Viewed by 736

Abstract

As water temperatures rise in streams due to global temperature variations, dams, and increased water usage, native fish species face uncertain futures. Our study defines the thermal limits of flannelmouth sucker larvae. By raising sucker eggs at three acclimation temperatures (11 °C, 16 [...] Read more.

As water temperatures rise in streams due to global temperature variations, dams, and increased water usage, native fish species face uncertain futures. Our study defines the thermal limits of flannelmouth sucker larvae. By raising sucker eggs at three acclimation temperatures (11 °C, 16 °C, and 22 °C), we defined ideal conditions for larval survival and the temperature tolerance range using critical thermal maximum (CTMax) and minimum (CTMin) trials. Larvae survived best at 16 °C. Within our three acclimation temperatures, our data suggest that larvae can survive static temperatures between 6.9 °C and 26.4 °C. Beyond an upper temperature of 34.8 °C and a lower temperature of 6.3 °C, these fish may fail to adapt. While flannelmouth suckers withstand high temperatures, even small temperature decreases prove detrimental. By defining the temperature limits of the flannelmouth sucker, we can make informed management decisions to preserve the populations of this desert fish. Full article

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

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14 pages, 4036 KiB

Open AccessArticle

Assessing the Effects of Dietary Tea Polyphenols on the Gut Microbiota of Loaches (Paramisgurnus dabryanus) under Chronic Ammonia Nitrogen Stress

by Yuqiao Chai, Shuhao Sun and Yingdong Li

Fishes 2024, 9(5), 180; https://doi.org/10.3390/fishes9050180 - 15 May 2024

Viewed by 1159

Abstract

This study examined the impact of tea polyphenols (TPs) on the intestinal flora of loaches (Paramisgurnus dabryanus) under chronic ammonia nitrogen stress using high-throughput sequencing. Two groups of 600 loaches were studied over one month, and they were separated into a [...] Read more.

This study examined the impact of tea polyphenols (TPs) on the intestinal flora of loaches (Paramisgurnus dabryanus) under chronic ammonia nitrogen stress using high-throughput sequencing. Two groups of 600 loaches were studied over one month, and they were separated into a control group and tea polyphenol group. Alpha and beta diversity analyses showed diverse bacterial communities, with significant differences in the abundance and uniformity observed initially but not between sampling time points. Cluster analyses revealed distinct differences in microbial communities between groups. A predictive function analysis indicated enrichment in pathways related to amino acid and nucleotide biosynthesis. These findings offer initial insights into how tea polyphenols may affect intestinal microbial communities in loaches under ammonia nitrogen stress. Full article

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

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13 pages, 2422 KiB

Open AccessArticle

Investigation of the Antiviral Mechanism of Curcumin Analog EF-24 against Siniperca cachuatsi Rhabdovirus

by Pei-Mo Ju, Shi-Wei Ma, Yi-Yang Li, Shi-Fan Zhang, Jun Li and Guang-Zhou Zhou

Fishes 2024, 9(5), 179; https://doi.org/10.3390/fishes9050179 - 15 May 2024

Viewed by 1181

Abstract

Siniperca chuatsi rhabdovirus (SCRV) is a major strain of viral fish virus resulting in multiple transmissions and devastating damage in aquaculture. Currently, there are no available approved therapeutics. In this study, we screened and identified a novel curcumin analog (EF-24) for evaluating its [...] Read more.

Siniperca chuatsi rhabdovirus (SCRV) is a major strain of viral fish virus resulting in multiple transmissions and devastating damage in aquaculture. Currently, there are no available approved therapeutics. In this study, we screened and identified a novel curcumin analog (EF-24) for evaluating its in vitro anti-SCRV properties and potential molecular mechanisms. Present results demonstrated that EF-24 could strongly delay the occurrence of cytopathic effects (CPEs) in epithelioma papulosum cyprinid cells (EPCs) and inhibit SCRV replication and viral nucleoprotein expression in the early stages of infection by the time-of-addition assay. Furthermore, flow cytometry analysis after Annexin V-FITC/PI double staining and immunofluorescence microscopy observation after JC-1 incubation showed that EF-24 downregulated cell mitochondrial apoptosis induced by SCRV. The enzymatic activities of caspase-3 and caspase-9 were also reduced after EF-24 treatment, indicating that EF-24 may protect cells from SCRV infection by decreasing mitochondrial intrinsic apoptosis in infected cells. Collectively, we demonstrated for the first time that the curcumin analog EF-24 possesses antiviral ability against SCRV, suggesting its potential for effective control of fish rhabdovirus spreading. Full article

(This article belongs to the Section Welfare, Health and Disease)

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22 pages, 4002 KiB

Open AccessArticle

Enhancing Growth and Intestinal Health in Triploid Rainbow Trout Fed a Low-Fish-Meal Diet through Supplementation with Clostridium butyricum

by Chang’an Wang, Fangyuan Li, Di Wang, Shaoxia Lu, Shicheng Han, Wei Gu, Haibo Jiang, Zhuang Li and Hongbai Liu

Fishes 2024, 9(5), 178; https://doi.org/10.3390/fishes9050178 - 14 May 2024

Cited by 1 | Viewed by 1059

Abstract

This study evaluates the effects of dietary Clostridium butyricum on growth performance and intestinal health in triploid rainbow trout (Oncorhynchus mykiss). Administered in a 12-week trial, five isonitrogenous and isolipidic feeds contained different C. butyricum levels [G1 (0), G2 (1.6 × [...] Read more.

This study evaluates the effects of dietary Clostridium butyricum on growth performance and intestinal health in triploid rainbow trout (Oncorhynchus mykiss). Administered in a 12-week trial, five isonitrogenous and isolipidic feeds contained different C. butyricum levels [G1 (0), G2 (1.6 × 10⁶ CFU/g), G3 (1.2 × 10⁷ CFU/g), G4 (1.1 × 10⁸ CFU/g), and G5 (1.3 × 10⁹ CFU/g)]. Significant enhancements in growth performance, including improved feed conversion ratios and specific growth rates in the G4 group, were indicative of enhanced nutrient utilization, corroborated by optimal digestive enzyme activity levels. Antioxidant capabilities were also enhanced in the G4 group, indicated by increased serum superoxide dismutase and catalase activities, along with a significant decrease in malondialdehyde levels. Gut microbiota analysis indicated a probiotic concentration-dependent modulation of microbial communities, with a marked enrichment in beneficial bacterial phyla like Firmicutes in the G4 group. This microbial shift correlated with significant downregulations in immune-related gene expressions, including interleukins (IL-1β, IL-8), NF-κB, MyD88, and TNF-α, highlighting an activated immune response. Correspondingly, serum lysozyme and immunoglobulin M contents were significantly elevated in the G4 group. Challenge tests with Aeromonas salmonicida exhibited the higher disease resistance of fish fed the G4 diet. In conclusion, the study shows the potential of dietary C. butyricum, especially at 1.1 × 10⁸ CFU/g, in enhancing the growth, health, and disease resistance of triploid rainbow trout through modulating gut microflora and stimulating immune responses. Full article

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

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11 pages, 2241 KiB

Open AccessArticle

Toxicity, Oxidative Stress, and Tissue Distribution of Butachlor in the Juvenile Chinese Mitten Crab (Eriocheir sinensis)

by Song Wu, Peng Wang, Ying Zhang, Li Huang, Qirui Hao, Lei Gao, Dongli Qin and Xiaoli Huang

Fishes 2024, 9(5), 177; https://doi.org/10.3390/fishes9050177 - 13 May 2024

Cited by 1 | Viewed by 1108

Abstract

The Chinese mitten crab (Eriocheir sinensis) is one of the most commercially important crustacean species in China. The aim of this study was to characterize the toxic effects of butachlor (an herbicide of the acetanilide class) on juvenile E. sinensis crabs. [...] Read more.

The Chinese mitten crab (Eriocheir sinensis) is one of the most commercially important crustacean species in China. The aim of this study was to characterize the toxic effects of butachlor (an herbicide of the acetanilide class) on juvenile E. sinensis crabs. The lethal effects and the acute toxicity of butachlor on juvenile E. sinensis specimens were assessed through a semi-static in vitro experiment. We determined the activities of superoxide dismutase (SOD) and catalase (CAT) as well as the levels of glutathione (GSH) and malondialdehyde (MDA) in the gills and the hepatopancreas of the juvenile crabs, at different time points over a 14-day short-term exposure to butachlor. Moreover, we measured the residual levels of butachlor in three different tissues (gills, hepatopancreas, and muscles) of the juvenile crabs over a longer period. Our findings revealed that butachlor is highly toxic for juvenile E. sinensis crabs. In fact, the median lethal concentration (LC₅₀) values of butachlor at 24, 48, 72, and 96 h were found to be 4.22, 1.84, 0.34, and 0.14 mg/L, respectively, while the safe concentration was 0.014 mg/L. The antioxidant defense ability of the juvenile E. sinensis crabs against butachlor was induced after exposure to the herbicide at a concentration of 0.01 mg/L. After 14 days of exposure to butachlor at 0.04 and 0.16 mg/L, both SOD and CAT were found to be significantly inhibited (p < 0.05), the GSH levels were found to be significantly decreased (p < 0.05) and the MDA levels were identified as significantly increased (p < 0.05). Moreover, after 14 days of exposure to butachlor at 0.16 mg/L, the activities of SOD and CAT as well as the content of GSH in the hepatopancreas were found to be significantly decreased (p < 0.05). Our results revealed that a high concentration of butachlor was capable of inducing oxidative stress and damage in juvenile E. sinensis crabs. The maximal residual value of butachlor was obtained in the gills, with a content of 4.56 μg/kg. Butachlor was not detected after 24 days in the aforementioned three tissues of the juvenile crabs, thereby indicating that it was effectively metabolized. Full article

(This article belongs to the Special Issue Advances in Crab Fisheries)

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3 pages, 147 KiB

Open AccessEditorial

Effect of Dietary Supplementation on the Growth and Immunity of Fish and Shellfish

by Changle Qi, Qiyou Xu, Jianhua Ming, Fei Song and Chuanpeng Zhou

Fishes 2024, 9(5), 176; https://doi.org/10.3390/fishes9050176 - 13 May 2024

Viewed by 1100

Abstract

With the rapid development of aquaculture, the shortage of high-quality dietary ingredients has become a critical problem limiting the sustainable development of aquaculture [...] Full article

(This article belongs to the Special Issue Effect of Dietary Supplementation on the Growth and Immunity of Fish and Shellfish)

14 pages, 2191 KiB

Open AccessArticle

Effect of an Ipomoea aquatica Floating Raft on the Water Quality, Antioxidant System, Non-Specific Immune Responses, and Microbial Diversity of Penaeus vannamei in an Aquaculture System

by Zhuohao Ruan, Ruilin Xie, Yifu Li, Yuanyuan Luo, Zufeng Weng and Wensheng Liu

Fishes 2024, 9(5), 175; https://doi.org/10.3390/fishes9050175 - 12 May 2024

Viewed by 1343

Abstract

Pacific white shrimp (Penaeus vannamei) is one of the main shrimp species cultivated around the world. Despite its high yields and easy handling, water pollution from intensive shrimp cultivation remains a serious problem in China. In this study, a compound aquaculture [...] Read more.

Pacific white shrimp (Penaeus vannamei) is one of the main shrimp species cultivated around the world. Despite its high yields and easy handling, water pollution from intensive shrimp cultivation remains a serious problem in China. In this study, a compound aquaculture model of P. vannamei and water spinach (Ipomoea aquatica) was used to investigate the effect of a water spinach floating raft on water quality, antioxidants, non-specific immune response, growth performance, and microbial diversity. The experimental design of this study consisted of two groups with three replicates for each, i.e., control group: aquatic monoculture (AM) system with only P. vannamei; treatment group: P. vannamei-I. aquatica raft aquaponics (AP) system with a 50% cover ratio with a water spinach floating raft. The experiment lasted for seven weeks. The results show that the concentrations of total phosphorus (TP), total nitrogen (TN), nitrate nitrogen (NO₃⁻-N), ammonia nitrogen (NH₄⁺-N), nitrite nitrogen (NO₂⁻-N), and active phosphorus (AP) in the AM group were higher than those in the AP group at different sampling times. The water quality index of the AP group was better than that of the AM group, indicating that water spinach can remove the nutrients from aquaculture water bodies. The average daily gain and survival rate of shrimp in the AP group were higher than those in the AM group. The total antioxidant capacity (T-AOC), catalase (CAT), superoxide dismutase (SOD), malondialdehyde (MDA), and acid phosphatase (ACP) in the AP group were better than those in the AM group. The Shannon–Wiener and Simpson indices of the gut, water, and sediment of the AP system were significantly higher than those in the AM system, which implied a higher abundance of microorganisms in the AP system. These results demonstrate that the application of a water spinach floating raft in aquaponics can not only improve the water quality, but also improve the growth performance, antioxidant system, and non-specific immune responses of Pacific white shrimp, while increasing the abundance of microorganisms in the aquaculture system and improving the ecological benefits in terms of the expenditure. Full article

(This article belongs to the Section Sustainable Aquaculture)

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15 pages, 2631 KiB

Open AccessArticle

Effects of Three Sources of Astaxanthin on the Growth, Coloration, and Antioxidant Capacity of Rainbow Trout (Oncorhynchus mykiss) during Long-Term Feeding

by Lei Wang, Xiaowen Long, Yaopeng Li, Yong Zhang, Weihong Sun and Xugan Wu

Fishes 2024, 9(5), 174; https://doi.org/10.3390/fishes9050174 - 10 May 2024

Viewed by 1102

Abstract

Astaxanthin is an important pigment for the rainbow trout Oncorhynchus mykiss. This study was conducted to investigate the effects of different sources of dietary astaxanthin on the growth, coloration, and antioxidant capacity of the commercial-sized O. mykiss during long-term feeding. Haematococcus pluvialis [...] Read more.

Astaxanthin is an important pigment for the rainbow trout Oncorhynchus mykiss. This study was conducted to investigate the effects of different sources of dietary astaxanthin on the growth, coloration, and antioxidant capacity of the commercial-sized O. mykiss during long-term feeding. Haematococcus pluvialis (HP), yeast Phaffia rhodozyma (PR), and synthetic astaxanthin (SA) were added to the basic feed (no astaxanthin, NA) to prepare the isonitrogenous and isolipidic experimental diets; the actual astaxanthin content values in the diets were 31.25, 32.96, and 31.50 mg/kg, respectively. Eighteen hundred O. mykiss, averaging 670 ± 20 g, were randomly divided into four groups and then fed with the experimental diet for four months. Dietary supplementation of P. rhodozyma and synthetic astaxanthin had no significant effects on the growth and tissue indexes of O. mykiss. In contrast, dietary supplementation with astaxanthin from H. pluvialis significantly increased the weight gain rate after four months of feeding. The fillet lightness of O. mykiss in the PR and SA was statistically lower than that in the NA and HP; the redness and astaxanthin content of fillet in the HP, PR, and SA groups were statistically higher than those in the NA. The total antioxidant capacity of the liver and serum in the HP was statistically higher than that in other diet groups, and a higher liver total superoxide dismutase activity was detected in the HP compared with the PR. Dietary supplementation of astaxanthin significantly increased the glutathione peroxidase activity in the liver and serum, and the highest serum glutathione peroxidase activity was detected in the HP, while dietary astaxanthin significantly decreased the malondialdehyde content in the liver and serum. Dietary supplementation of PR significantly increased the fillet ash content, while the highest fillet total lipid content was detected in the HP. Dietary astaxanthin significantly improved fillet redness and antioxidant capacity, among which H. pluvialis astaxanthin has greater effects on improving weight gain, antioxidant capacity, and fillet total lipid content. Full article

(This article belongs to the Section Nutrition and Feeding)

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22 pages, 2305 KiB

Open AccessArticle

Coexisting in the Surf Zone: Age and Feeding Habits of the Spotted Seabass (Dicentrarchus punctatus) and European Seabass (Dicentrarchus labrax) on the Gulf of Cádiz Beaches (Southwest Iberian Peninsula)

by Carlos Rodríguez-García, Ana Toro-Podadera, Jesica Sarmiento-Carbajal and Remedios Cabrera-Castro

Fishes 2024, 9(5), 173; https://doi.org/10.3390/fishes9050173 - 9 May 2024

Viewed by 1152

Abstract

Various commercial fish species utilize different coastal habitats as nurseries in their juvenile stages, with surf zones being particularly crucial due to the protection and abundant food resources they offer. Among the species that rely on these areas are the spotted seabass ( [...] Read more.

Various commercial fish species utilize different coastal habitats as nurseries in their juvenile stages, with surf zones being particularly crucial due to the protection and abundant food resources they offer. Among the species that rely on these areas are the spotted seabass (Dicentrarchus punctatus) and the European seabass (Dicentrarchus labrax). This study aimed to investigate the age and feeding habits of surf zone specimens of these species and explore their environmental adaptations. The average size for D. punctatus was 16.94 ± 4.05 cm, and for D. labrax, it was 23.23 ± 6.30 cm. The length–weight relationship for D. punctatus was TW = 0.013*TL^2.885 (parameter a: 95% CI: 0.012–0.014; parameter b: 95% CI: 2.854–2.917), and for D. labrax, it was TW = 0.008*TL^3.095 (parameter a: 95% CI: 0.006–0.009; parameter b: 95% CI: 3.040–3.151). In both D. punctatus (79.20%) and D. labrax (75.92%), the predominant age classes were 1+ and 2+. Significant variations in age class abundance were observed in D. punctatus based on the time of day, lunar phase, and season, while D. labrax showed variations only by season. A diet analysis revealed that both species primarily consume mysids and fish, with D. punctatus showing dietary variations related to the time of day, lunar phase, and season, and D. labrax showing variations with the time of day and season. Full article

(This article belongs to the Section Biology and Ecology)

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14 pages, 3119 KiB

Open AccessArticle

Cloning, Characterization and Functional Analysis of Caspase 8-like Gene in Apoptosis of Crassostrea hongkongensis Response to Hyper-Salinity Stress

by Jinji Lin, Ziqi Yu, Yang Leng, Jiexiong Zhu, Feifei Yu, Yishan Lu, Jiayu Chen, Wenhao He, Yixin Zhang and Yaoshen Wen

Fishes 2024, 9(5), 172; https://doi.org/10.3390/fishes9050172 - 9 May 2024

Viewed by 1062

Abstract

Caspase-8, a member of the caspase family, is an initiating caspase and plays a crucial role in apoptosis. In this study, the full-length cDNA of caspase8-like (CASP8-like) was isolated from Crassostrea hongkongensis (C. hongkongensis) by RACE-PCR. ChCASP8-like contained [...] Read more.

Caspase-8, a member of the caspase family, is an initiating caspase and plays a crucial role in apoptosis. In this study, the full-length cDNA of caspase8-like (CASP8-like) was isolated from Crassostrea hongkongensis (C. hongkongensis) by RACE-PCR. ChCASP8-like contained a 1599-bp open reading frame (ORF) encoding 533 amino acids with two conserved death effector domains (DEDs) and a cysteine aspartase cysteine structural domain (CASc). Amino acid sequence comparison showed that ChCASP8-like shared the highest identity (85.4%) with CASP8-like of C. angulata. The tissue expression profile showed that ChCASP8-like was constitutively expressed in gills, hepatopancreas, mantle, adductor muscle, hemocytes and gonads, and was significantly upregulated in hemocytes, hepatopancreas and gills under hyper-salinity stress. The apoptosis-related genes, including ATR, CHK1, BCL-XL, CASP8-like, CASP9 and CASP3, were significantly activated by hyper-salinity stress, but were remarkably inhibited by ChCASP8-like silencing. The caspase 8 activity was increased by 1.7-fold after hyper-salinity stress, and was inhibited by 9.4% by ChCASP8-like silencing. Moreover, ChCASP8-like silencing clearly alleviated the apoptosis resulting from hyper-salinity stress. These results collectively demonstrated that ChCASP8-like played a crucial role in inducing apoptosis against hyper-salinity stress. Full article

(This article belongs to the Section Aquatic Invertebrates)

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20 pages, 4918 KiB

Open AccessArticle

Reducing Artisanal Fishery Impact on Marine Community: New Data from Comparison of Innovative and Traditional Gear

by Manfredi Madia, Massimiliano Bottaro, Tiziana Cillari, Andrea Li Vorsi, Luca Castriota, Maria Rita Amico, Sergio Bizzarri, Teresa Maggio, Manuela Falautano, Michele Gristina, Ilaria Di Lauro, Floriana Trova, Patrizia Perzia, Roberto D’Ambra, Enrico Casola and Mauro Sinopoli

Fishes 2024, 9(5), 171; https://doi.org/10.3390/fishes9050171 - 8 May 2024

Viewed by 1175

Abstract

Fishery resources overexploitation, together with bycatch and discards, have an impact on marine ecosystems. The adoption of technologically innovative gears is a possible solution to reduce the discard and to enhance the sustainability of fishery, mainly in artisanal fisheries that represent about 80% [...] Read more.

Fishery resources overexploitation, together with bycatch and discards, have an impact on marine ecosystems. The adoption of technologically innovative gears is a possible solution to reduce the discard and to enhance the sustainability of fishery, mainly in artisanal fisheries that represent about 80% of the EU Mediterranean fleet. In the perspective of fishery sustainability, it is necessary to study and test alternative gears to the traditional ones, also with collaboration of fishers. In the present study, results of experimental fishing activities carried out in two Mediterranean areas with traditional and innovative gears of small-scale fishing are reported. Thirty-four hauls were carried out to compare the catch of two types of trammel nets: a traditional one and experimental guarding net. Additionally, 12 hauls were carried out to compare collapsible pots and traditional pots. No significant differences were recorded between trammel nets in terms of commercial catch and discard. However, interesting differences in discard composition were recorded, with higher Elasmobranchs presence in trammel nets, including species assessed as critically endangered and vulnerable. The use of trapula pots in place of traditional ones showed a lower discard of specific resources and an advantage for fishers in terms of space occupied on board. Full article

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

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17 pages, 2564 KiB

Open AccessArticle

Effects of RNA Interference with Acetyl-CoA Carboxylase Gene on Expression of Fatty Acid Metabolism-Related Genes in Macrobrachium rosenbergii under Cold Stress

by Hua Zhong, Xinyi Yao, Haihui Tu, Zhenglong Xia, Miaoying Cai, Qiang Sheng, Shaokui Yi, Guoliang Yang and Qiongying Tang

Fishes 2024, 9(5), 170; https://doi.org/10.3390/fishes9050170 - 8 May 2024

Viewed by 947

Abstract

Macrobrachium rosenbergii is a warm water species, and low temperature is a limiting factor for its growth and survival. In order to explore the role of the acetyl-CoA-carboxylase (ACC) gene in response to the cold stress of M. rosenbergii, we [...] Read more.

Macrobrachium rosenbergii is a warm water species, and low temperature is a limiting factor for its growth and survival. In order to explore the role of the acetyl-CoA-carboxylase (ACC) gene in response to the cold stress of M. rosenbergii, we investigated the effects of RNA interference (RNAi) with the ACC gene on the expression of fatty acid metabolism-related genes and the mortality of M. rosenbergii under cold stress. The results showed that different siRNA sequences and different injection concentrations had different inhibiting effects on ACC gene expression, and siRNA-III with an injection concentration of 2.0 μg/g (siRNA/prawn body weight) had the best interference effect. With the optimal siRNA and the optimal concentration under cold stress, the expressions of three fatty acid metabolism-related genes, FabD, echA, and ACOT, were generally significantly down-regulated. Compared to negative (scrambled-siRNA) and blank (PBS) control groups, the expression of FabD in the interference group was extremely significantly down-regulated at 12 h in the hepatopancreas and at 18 h in the muscles and gills; EchA was highly significantly down-regulated at 6 and 12 h in the muscles and gills; and ACOT was extremely significantly down-regulated and kept declining in the gills. Within 6–18 h after injection under cold stress, the mortality rate of the siRNA interference group (75%) was much lower than that of the negative (95%) or blank control group (97.5%), and all prawns died after 24 h. In conclusion, RNA interference with the ACC gene inhibited the expression of some fatty acid metabolism-related genes, and could partly improve the tolerance of M. rosenbergii to cold stress, indicating that the ACC gene might play an important role in the response of M. rosenbergii to cold stress. Full article

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

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12 pages, 932 KiB

Open AccessArticle

Development and Characterization of Fifteen Polymorphic Microsatellite Loci for Rare and Endangered Species within Luciobarbus Heckel, 1843 Genus in the Aral Basin and Their Conservation Application

by Kamila Adyrbekova, Silvia Perea and Ignacio Doadrio

Fishes 2024, 9(5), 169; https://doi.org/10.3390/fishes9050169 - 7 May 2024

Viewed by 1192

Abstract

Biodiversity conservation entails not only the preservation of specific taxa but also genetic diversity. Despite the crucial role of molecular data in freshwater fish conservation management, there is a scarcity of information regarding the genetic diversity of Luciobarbus Heckel, 1843 (Actinopterygii, Cyprinidae) populations [...] Read more.

Biodiversity conservation entails not only the preservation of specific taxa but also genetic diversity. Despite the crucial role of molecular data in freshwater fish conservation management, there is a scarcity of information regarding the genetic diversity of Luciobarbus Heckel, 1843 (Actinopterygii, Cyprinidae) populations in the Aral system. Therefore, the primary aim of this study was to provide genetic information on two native species of the Luciobarbus genus found in the Aral system: L. conocephalus (Kessler, 1872) and L. brachycephalus (Kessler, 1872). These species, like many others in the Aral system, confront the imminent threat of extinction due to system alterations. However, genetic studies on these species at the nuclear level are challenging because Luciobarbus is an allotetraploid genus. Consequently, genetic investigations thus far have focused mainly on sequencing mitochondrial genes due to their haploid nature. This study has successfully developed fifteen new polymorphic microsatellite loci, which can prove to be valuable for population genetics, conservation, and other pertinent research on these species. Full article

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

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23 pages, 7097 KiB

Open AccessArticle

Effect of Toxicity of Chromium (VI) Stressors Alone and Combined to High Temperature on the Histopathological, Antioxidation, Immunity, and Energy Metabolism in Fish Phoxinus lagowskii

by Tingting Hu, Cunrun Ye, Zhaoyang Ning, Tianmei Liu and Weijie Mu

Fishes 2024, 9(5), 168; https://doi.org/10.3390/fishes9050168 - 5 May 2024

Viewed by 1198

Abstract

Fish in aquatic ecosystems are often impacted by environmental stressors like temperature fluctuations and exposure to heavy metals. Chromium (Cr⁶⁺) is a known environmental pollutant that poses a threat to aquatic life. Various environmental factors, such as water temperature, have been [...] Read more.

Fish in aquatic ecosystems are often impacted by environmental stressors like temperature fluctuations and exposure to heavy metals. Chromium (Cr⁶⁺) is a known environmental pollutant that poses a threat to aquatic life. Various environmental factors, such as water temperature, have been found to affect the toxicity of dissolved chemicals in aquatic ecosystems. We investigated the toxicity of combinations of different concentrations of hexavalent chromium (Cr⁶⁺) with high temperatures in fish. Hematological indices demonstrated changes in white blood cells (WBCs), hematocrit (HCT), red blood cells (RBCs), and hemoglobin (Hb) levels during the exposure. The qualitative and semi-quantitative analyses of different tissues confirmed that higher concentrations of Cr⁶⁺ caused more significant damage than lower concentrations, with evident alterations observed in circulatory and regressive aspects. Furthermore, brain acetylcholinesterase levels decreased in both single heavy metal exposure and combined exposure at a high temperature. The activity of antioxidant oxidase and immunological parameters increased in all treatment groups compared with the control group following long-term exposure. A significant and increased effect of Cr⁶⁺ in the high-temperature groups was observed on the evaluated biomarkers, suggesting a possible synergistic effect between Cr⁶⁺ and increased temperature. The integrated biomarker response (IBR) reported the highest level of stress at 10 mg/L Cr⁶⁺ combined with high temperature. The IBR analysis revealed that the highest activity of response enzymes, such as acid phosphatase (ACP), superoxide dismutase (SOD), and glutathione S-transferases (GST), was observed in the liver, whereas the gills displayed alkaline phosphatase (ALP), GST, and SOD activity, and the kidneys demonstrated SOD, ACP, and aspartate aminotransferase (AST) to be most active. Through histopathology, antioxidant enzymes, and metabolism- and immunity-related enzymes, we determined that high temperatures enhance the potential toxicity of Cr⁶⁺ in fish. We recommend conducting a thorough assessment of the impact of climate change, particularly temperature fluctuations, when studying the toxic effects of metal pollution, like chromium, in aquatic ecosystems. Full article

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25 pages, 380 KiB

Open AccessReview

The Role of Functional Feed Additives in Enhancing Aquaculture Sustainability

by Abigail John Onomu and Grace Emily Okuthe

Fishes 2024, 9(5), 167; https://doi.org/10.3390/fishes9050167 - 5 May 2024

Cited by 3 | Viewed by 4058

Abstract

Aquaculture serves as a source of protein and livelihood and is an alternative to capture fisheries, thereby reducing pressure on the wild. However, aquaculture tends to be limited by sustainability issues, which include overdependency on fishmeal, the high cost associated with fishmeal, the [...] Read more.

Aquaculture serves as a source of protein and livelihood and is an alternative to capture fisheries, thereby reducing pressure on the wild. However, aquaculture tends to be limited by sustainability issues, which include overdependency on fishmeal, the high cost associated with fishmeal, the environmental impact of aquaculture activities, which may be detrimental to aquatic lives and the environment, and the use of antibiotics to treat diseases, which may have an adverse effect in their host or the environment. Efforts are being made toward attaining practical ways to enhance aquaculture sustainability. One such effort is using functional feed additives in feed formulation. Functional feed additives are dietary ingredients incorporated in feed formulations, not only for the usual provision of basic nutritional requirements as offered by traditional feed but also for growth and health enhancement; environmental and economic gain. This review emphasizes the importance of incorporating functional feed additives such as probiotics, prebiotics, symbiotics, and phytogenics. This study evaluates and presents holistic information on functional additives, their roles in enhancing aquaculture sustainability, and the challenges encountered in their application. Full article

(This article belongs to the Special Issue Feed Additives in Aquaculture)

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12 pages, 962 KiB

Open AccessArticle

Assessing the Conservation Value of Artificial and Natural Reefs via Ichthyoplankton Spatio-Temporal Dynamics

by Carlos Adrián Sánchez-Caballero, José Manuel Borges-Souza, Ricardo Javier Saldierna-Martínez and Avigdor Abelson

Fishes 2024, 9(5), 166; https://doi.org/10.3390/fishes9050166 - 4 May 2024

Viewed by 1667

Abstract

The distribution of fish eggs and larvae (ichthyoplankton) reflects spawning and nursery areas as well as dispersal routes. This study’s goal is to demonstrate how the identification of ichthyoplankton species and stages and their spatial distribution among natural reefs (NRs) and artificial reefs [...] Read more.

The distribution of fish eggs and larvae (ichthyoplankton) reflects spawning and nursery areas as well as dispersal routes. This study’s goal is to demonstrate how the identification of ichthyoplankton species and stages and their spatial distribution among natural reefs (NRs) and artificial reefs (ARs) may serve as decision-making tools in conservation and fishery management. Natural reefs exhibited an eight-times higher abundance of eggs, as well as the highest abundance of larvae in the yolk-sac and preflexion phases. In contrast, ARs had the highest abundance of larvae in the flexion and postflexion phases. Natural reefs may serve as breeding grounds for Scaridae, Labridae, and Mugilidae; whereas, ARs may serve as breeding sites for Lutjanidae, Synodontidae, Carangidae, Fistularidae, and Haemulidae. Our study revealed differences between ARs and NRs, which demonstrate the potential of artificial reefs to expand the supply and settlement options of reef fishes and consequently can lead to increased fish production with potential benefits to adjacent fishing areas through connectivity. Thus, ARs as no-take sites can be effective tools for both fishery management and biodiversity conservation. The findings highlight the potential use of ichthyoplankton tools and the importance of considering both types of reefs in marine conservation and management efforts. Full article

(This article belongs to the Special Issue Biology and Ecology of Coral Reef Fishes)

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21 pages, 2936 KiB

Open AccessArticle

Circularity Assessment in Aquaculture: The Case of Integrated Multi-Trophic Aquaculture (IMTA) Systems

by Daniel Checa, Brett M. Macey, John J. Bolton, Marissa Brink-Hull, Pauline O’Donohoe, Alessandro Cardozo, Luis Henrique Poersch and Inmaculada Sánchez

Fishes 2024, 9(5), 165; https://doi.org/10.3390/fishes9050165 - 4 May 2024

Cited by 4 | Viewed by 2930

Abstract

Aquaculture is a strategic sector that aims to meet the increased demands for healthy food for current and future populations. However, this progression needs to be sustainable, which can potentially be achieved by the implementation of circular practices. Integrated multi-trophic aquaculture (IMTA) systems [...] Read more.

Aquaculture is a strategic sector that aims to meet the increased demands for healthy food for current and future populations. However, this progression needs to be sustainable, which can potentially be achieved by the implementation of circular practices. Integrated multi-trophic aquaculture (IMTA) systems promote the incorporation of circular principles. Nevertheless, the lack of harmonized definitions and standards impedes the quantification of these circular attributes. This study aims to explore the potential principles embedded in IMTA and the existing alternatives to quantify circularity. Two basic pillars (nutrient management and resource use efficiency) were identified as the most relevant circularity attributes for IMTA systems and were quantified through aquaculture-specific indicators. Bioremediation indicators, together with the efficiency indicators in terms of feed, water, energy, and infrastructure materials used, were selected to evaluate the circularity performance of four IMTA trials in three aquaculture facilities in Ireland, Brazil, and South Africa. Salmon, white shrimp, tilapia, abalone, and sea urchins were studied and cultivated together in various combinations with several low-trophic species in these IMTA trials to evaluate the improvement in circularity compared with corresponding monoculture conditions. The results showed an increase in circularity of up to 90% in terms of water recirculation, as well as bioremediation, which was improved by 80%–90%, providing evidence for the potential role of IMTA in the circularity transition. Full article

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

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17 pages, 1990 KiB

Open AccessArticle

Genetic Basis for Morphological Variation in the Zebrafish Danio rerio: Insights from a Low-Heterozygosity Line

by Gil Martinez-Bautista, Pamela Padilla and Warren W. Burggren

Fishes 2024, 9(5), 164; https://doi.org/10.3390/fishes9050164 - 2 May 2024

Viewed by 1321

Abstract

Data variability complicates reproducibility and the interpretation of experimental results. Different animal models have been employed to decrease variability to enhance experimental power. However, variation frequently persists among and within strains/lines. In zebrafish (Danio rerio), inbred lines (e.g., NHGRI-1) derived from [...] Read more.

Data variability complicates reproducibility and the interpretation of experimental results. Different animal models have been employed to decrease variability to enhance experimental power. However, variation frequently persists among and within strains/lines. In zebrafish (Danio rerio), inbred lines (e.g., NHGRI-1) derived from wild-type lines have been produced to greatly decrease genetic variation, with the goal of providing better understanding of genetic backgrounds that may influence the experimental outcome of studies employing such lines. We hypothesized that variations in morphological phenotypes shaped by environmental stressors early in development are correlated with the intrinsic degree of genetic variability of zebrafish lines. We compared morphological variability (yolk–chorion ratio, body mass, embryo mass, total length, condition factor, and specific growth rate) in wild-type AB and NHGRI-1 zebrafish lines as a function of their responses to altered temperature and oxygen availability during the first 7 days post-fertilization. Overall, both lines showed similar developmental trajectories for yolk–chorion ratio, embryo mass, and total length. Additionally, condition factor and specific growth rate showed similar responses within each line, regardless of temperature and hypoxia. Importantly, the coefficient of variation for each variable was significantly lower in NHGRI-1 than AB larvae for 151 of 187 assessed morphological endpoints. Thus, the low-heterozygosity NHGRI-1 zebrafish line can be useful for decreasing inter-individual variation in morphological responses to environmental stressors, thereby aiding in the interpretation of results and enhancing experimental reproducibility. Full article

(This article belongs to the Section Genetics and Biotechnology)

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18 pages, 1847 KiB

Open AccessReview

Supposed Virulence Factors of Flavobacterium psychrophilum: A Review

by Věra Vaibarová and Alois Čížek

Fishes 2024, 9(5), 163; https://doi.org/10.3390/fishes9050163 - 30 Apr 2024

Cited by 1 | Viewed by 1834

Abstract

Flavobacterium psychrophilum is currently one of the most important pathogens in aquaculture worldwide, causing high losses to farmed salmonids particularly during early growth stages with significant economic impact. Despite previous attempts, no effective vaccine has been developed, and protection against introduction into farms [...] Read more.

Flavobacterium psychrophilum is currently one of the most important pathogens in aquaculture worldwide, causing high losses to farmed salmonids particularly during early growth stages with significant economic impact. Despite previous attempts, no effective vaccine has been developed, and protection against introduction into farms is difficult due to the ubiquitous occurrence of the pathogen. A better understanding of the mechanism of disease development is essential for targeted therapeutic and preventive measures in farms. Unfortunately, the pathogenesis of diseases caused by F. psychrophilum has not been elucidated yet. Previously, several putative virulence factors have been identified. Some appear to be essential for disease development, while others are probably dispensable. The importance of some factors has not yet been explored. This review focuses on the supposed virulence factors of F. psychrophilum and the current knowledge about their importance in the pathogenesis of the disease. Full article

(This article belongs to the Special Issue Fish Pathogens: Infection and Biological Control)

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20 pages, 1990 KiB

Open AccessArticle

Queen Triggerfish Balistes vetula Age-Based Population Demographics and Reproductive Biology for Waters of the North Caribbean

by Jesús M. Rivera Hernández and Virginia R. Shervette

Fishes 2024, 9(5), 162; https://doi.org/10.3390/fishes9050162 - 29 Apr 2024

Viewed by 1865

Abstract

Queen triggerfish Balistes vetula is an important reef-associated species for commercial fisheries in the U.S. Caribbean. It exhibits a relatively unique reproductive strategy as a nesting benthic spawner, investing substantial energy in territorial defense, building and maintaining nests, and caring for fertilized eggs [...] Read more.

Queen triggerfish Balistes vetula is an important reef-associated species for commercial fisheries in the U.S. Caribbean. It exhibits a relatively unique reproductive strategy as a nesting benthic spawner, investing substantial energy in territorial defense, building and maintaining nests, and caring for fertilized eggs during the reproductive season. Prior to this study, no comprehensive life history information existed in the literature for queen triggerfish. This study provides the first comprehensive documentation of age, growth, size/age at sexual maturity, reproductive seasonality, and reproductive output for a Balistes species in the Caribbean. From 2013 to 2023, we collected 2190 fish samples from fisheries-dependent and -independent sources from the waters of Puerto Rico and the U.S. Virgin Islands. Fish ranged from 67 to 477 mm fork length (FL). We documented that queen triggerfish is sexually dimorphic with males attaining larger mean sizes-at-age compared to females and the species is characterized by a moderately young age at median sexual maturity (A₅₀ = 3.3 y). The maximum age for our U.S. Caribbean samples was 23 y based on increment counts from otoliths. Spawning season encompassed the months of December to August in the region, and female spawning frequency ranged from an estimated 2 to 84 times per year; female spawning frequency increased with increasing size and age of fish. We documented that commercial fishers in the U.S. Caribbean mainly target “plate-size” individuals, defined in our study as 235–405 mm FL, which appears to act as a self-imposed slot size range limit and results in the fishery not removing individuals in the smallest and largest size groups at high rates. The percentage of immature fish from fisheries-dependent sources was close to 0 (0.8%). Commercial fishing for queen triggerfish in the region currently appears to be sustainable, but monitoring of the population should continue. Full article

(This article belongs to the Section Biology and Ecology)

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13 pages, 5609 KiB

Open AccessArticle

Does the Artificial Enhancement and Release Activity Affect the Genetic Diversity of Marbled Rockfish Sebastiscus marmoratus in Zhoushan Waters?

by Senping Jiang, Xinyi Chen, Pengfei Li, Haoxue Wang, Jiji Li, Kaida Xu and Yingying Ye

Fishes 2024, 9(5), 161; https://doi.org/10.3390/fishes9050161 - 28 Apr 2024

Viewed by 1011

Abstract

Artificial enhancement and release activity is an important method in the restoration of fishery resources. In order to understand the possible genetic effect of hatchery-released populations on wild populations during the artificial enhancement and release activities of Sebastiscus marmoratus in Zhoushan waters, we [...] Read more.

Artificial enhancement and release activity is an important method in the restoration of fishery resources. In order to understand the possible genetic effect of hatchery-released populations on wild populations during the artificial enhancement and release activities of Sebastiscus marmoratus in Zhoushan waters, we utilized mitochondrial DNA control region sequences to examine the genetic diversity in four S. marmoratus populations, including one farmed population, one released population and two wild populations. A total of 68 haplotypes from 123 individuals were detected, including 3 shared haplotypes. Haplotype diversity ranged from 0.944 to 0.980, with a mean of 0.966. The nucleotide diversity ranged from 0.020 to 0.025, with a mean of 0.022. Analysis of Molecular Variance (AMOVA) indicated that the primary genetic variation occurs within populations and the index of genetic differentiation between populations (F_ST) among the four populations showed no differentiation. The results indicate that the current artificial enhancement and release has not impacted the S. marmoratus population in Zhoushan waters. Continued long-term monitoring is essential to protect the high-quality germplasm resources of S. marmoratus. Full article

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25 pages, 1351 KiB

Open AccessReview

Adriatic Sea Fishery Product Safety and Prospectives in Relation to Climate Change

by Edmond Hala and Rigers Bakiu

Fishes 2024, 9(5), 160; https://doi.org/10.3390/fishes9050160 - 28 Apr 2024

Cited by 5 | Viewed by 1600

Abstract

This bibliographic study addresses key aspects related to fishing, product safety, and climate change in the Adriatic Sea region. The examination of product safety focuses on the assessment of contaminants originating from human activities such as industry, mining, agriculture, and household waste disposal. [...] Read more.

This bibliographic study addresses key aspects related to fishing, product safety, and climate change in the Adriatic Sea region. The examination of product safety focuses on the assessment of contaminants originating from human activities such as industry, mining, agriculture, and household waste disposal. The contamination of the aquatic environment has emerged as a pressing global concern, extending to the Adriatic basin. Aquatic organisms, including fish, are prone to accumulating pollutants directly from polluted water sources and indirectly through the food web. The bio-accumulation of potentially hazardous substances, particularly heavy metals, pesticides, PCBs, PAHs, and antibiotic resistance in aquatic organisms, poses a significant threat to human health. Climate change effects will deplete our seafood supply in terms of quantity and safety owing to negative consequences such as higher levels of pollution, parasites, viruses, infections, acidification, and toxicities such as shellfish poisoning. Global food safety strategies should be developed to reduce greenhouse gas emissions and promote environmentally friendly technology, which indirectly affects seafood quality and microbiological safety, especially for the Adriatic Sea, which is part of the Mediterranean Sea, characterized by the most polluted waters in the world. Full article

(This article belongs to the Section Processing and Comprehensive Utilization of Fishery Products)

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21 pages, 6989 KiB

Open AccessArticle

Mechanistic Insights into Nonylphenol Stress on BMP2 and BMP4 Gene Expression in Red Crucian Carp (Carassius auratus Red var.)

by Die Li, Xiaojuan Cui, Shuailin Chen, Jia Xu, Yujing Li, Qiongyu Zhang and Yuandong Sun

Fishes 2024, 9(5), 159; https://doi.org/10.3390/fishes9050159 - 28 Apr 2024

Viewed by 978

Abstract

Nonylphenol (NP) is a known endocrine-disrupting chemical (EDC) that has been shown to affect bone development in mammals. However, the detrimental impacts of NP on the skeletal growth and development of aquatic species, especially bony fish, remain poorly understood. Bone morphogenic proteins (BMPs), [...] Read more.

Nonylphenol (NP) is a known endocrine-disrupting chemical (EDC) that has been shown to affect bone development in mammals. However, the detrimental impacts of NP on the skeletal growth and development of aquatic species, especially bony fish, remain poorly understood. Bone morphogenic proteins (BMPs), essential for bone formation and osteoblast differentiation, act through the BMP-Smad signaling pathway. In this study, two BMP genes, BMP2 and BMP4, were cloned and characterized in the red crucian carp (Carassius auratus red var.). The full-length cDNAs of BMP2 and BMP4 were 2029 bp and 2095 bp, respectively, encoding polypeptides of 411 and 433 amino acids, and share a typical TGF-β domain with other BMPs. The tissue expression patterns of both genes were identified, showing ubiquitous expression across all studied tissues. Additionally, the exposure of embryos or adult fish to NP stress resulted in a downregulation of BMP2, BMP4, and other genes associated with the BMP-Smad signaling pathway. Moreover, the combined treatment of adult fish with NP and the specific BMP receptor inhibitor significantly reduced these genes’ expression. These findings elucidate the mechanism of NP stress on BMP2 and BMP4, suggesting a role for the BMP-Smad signaling pathway in the response to endocrine-disrupting chemicals in fish. Full article

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

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