Fishes

15 pages, 3973 KiB

Open AccessFeature PaperArticle

Trawl Fishing Fleet Operations Used to Illustrate the Life Cycle of the Southern Brown Shrimp: Insights to Management and Sustainable Fisheries

by Ualerson I. Peixoto, Adauto S. Mello-Filho, Bianca Bentes and Victoria J. Isaac

Fishes 2022, 7(3), 141; https://doi.org/10.3390/fishes7030141 - 17 Jun 2022

Viewed by 1664

Abstract

The purpose of this study was to better understand the life cycle of brown shrimp along the Amazon Continental Shelf by using spatial and temporal trawl fleet activities. A total of 208,121 specimens and 1281 trawls were studied throughout the course of 13 [...] Read more.

The purpose of this study was to better understand the life cycle of brown shrimp along the Amazon Continental Shelf by using spatial and temporal trawl fleet activities. A total of 208,121 specimens and 1281 trawls were studied throughout the course of 13 years of shrimp size composition. To investigate differences in length composition between fishing grounds, months, and depth, a PERMANOVA analysis was employed. A geographic information system was developed for environmental characterisation and spatiotemporal trawl fleet distribution. Our findings show that the industrial trawl shrimp fleet has a close relationship with shrimp biological characteristics, following shrimp migration patterns in different months, locations, and depths during different stages of their life cycle, and that this fleet acts on two-yearly cohorts. The management measures of limiting effort (number of vessels) appear enough to avoid overcapitalisation, but the closed period and a proposed no-take fishing zone appear insufficient for what was originally proposed. Ecosystem-based management strategies should be addressed immediately because they would be far more effective than traditional fishery-based management measures in promoting sustainable fishing. Full article

(This article belongs to the Section Fishery Economics, Policy, and Management)

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16 pages, 6797 KiB

Open AccessArticle

Conversion of Fishery Waste to Proteases by Streptomyces speibonae and Their Application in Antioxidant Preparation

by Thi Ngoc Tran, Chien Thang Doan, Van Bon Nguyen, Anh Dzung Nguyen and San-Lang Wang

Fishes 2022, 7(3), 140; https://doi.org/10.3390/fishes7030140 - 14 Jun 2022

Cited by 1 | Viewed by 2011

Abstract

Proteinaceous wastes from the fishery process are an abundant renewable resource for the recovery of a variety of high-value products. This work attempted to utilize several proteinaceous wastes to produce proteases using the Streptomyces speibonae TKU048 strain. Among different possible carbon and nitrogen [...] Read more.

Proteinaceous wastes from the fishery process are an abundant renewable resource for the recovery of a variety of high-value products. This work attempted to utilize several proteinaceous wastes to produce proteases using the Streptomyces speibonae TKU048 strain. Among different possible carbon and nitrogen sources, the protease productive activity of S. speibonae TKU048 was optimal on 1% tuna head powder. Further, the casein/gelatin/tuna head powder zymography of the crude enzyme revealed the presence of three/nine/six proteases, respectively. The crude-enzyme cocktail of S. speibonae TKU048 exhibited the best proteolytic activity at 70 °C and pH = 5.8. Sodium dodecyl sulfate strongly enhanced the proteolytic activity of the cocktail, whereas FeCl₃, CuSO₄, and ethylenediaminetetraacetic acid could completely inhibit the enzyme activity. Additionally, the crude-enzyme cocktail of S. speibonae TKU048 could efficiently enhance the 2,2-diphenyl-1-picrylhydrazyl and 2,2′-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) radical scavenging activities of all tested proteinaceous materials including the head, viscera, and meat of tuna fish; the head, viscera, and meat of tilapia fish; the head, meat, and shell of shrimp; squid pen; crab shell; and soybean. Taken together, S. speibonae TKU048 revealed potential in the reclamation of proteinaceous wastes for protease production and antioxidant preparation. Full article

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14 pages, 4483 KiB

Open AccessArticle

Molecular Cloning of Heat Shock Protein 60 (SpHSP60) from Schizothorax prenanti and the Gene Expressions of Four SpHSPs during Lipopolysaccharide (LPS) Infection

by Jianlu Zhang, Jiqin Huang, Cheng Fang, Wanchun Li, Hu Zhao, Fei Kong, Han Zhang, Hongxing Zhang and Qijun Wang

Fishes 2022, 7(3), 139; https://doi.org/10.3390/fishes7030139 - 13 Jun 2022

Cited by 3 | Viewed by 1884

Abstract

Heat shock proteins (HSPs) play a key role in anti-stress and immune processes and are associated with autoimmune diseases. In order to explore the immunological role of HSPs from Schizothorax prenanti (S. prenanti), SpHSP60 was cloned for the first [...] Read more.

Heat shock proteins (HSPs) play a key role in anti-stress and immune processes and are associated with autoimmune diseases. In order to explore the immunological role of HSPs from Schizothorax prenanti (S. prenanti), SpHSP60 was cloned for the first time in this study, and the gene expressions of SpHSP27, SpHSP60, SpHSP70 and SpHSP90 in the hepatopancreas, head kidney, hindgut and spleen were analyzed by quantitative real-time PCR (qPCR) after treatment with lipopolysaccharide (LPS). The open reading frame of the SpHSP60 gene (GenBank accession number ON245159) is 1728 bp. It encodes a protein of 575 amino acids. Its C-terminus is a highly conserved and repeated glycine sequence, which is an important cofactor in ATP binding. Compared with the control group, most of the SpHSPs were significantly upregulated in the tissues examined at 12 or 24 h after LPS challenge. The most abundant expression of SpHSP70 was found in the head kidney at 24 h after LPS injection, followed by SpHSP27 in the spleen at 24 h; both of these SpHSPs displayed strong expression under the LPS stresses, about 20–70 fold more than that of SpHSP60 and SpHSP90. The temporal expression patterns of the four SpHSP genes were different in the four tissues examined. Taken together, the results suggest that SpHSP27, SpHSP60, SpHSP70 and SpHSP90 participate in innate immunity stimulated by LPS, and the response intensity of the SpHSPs was organ-specific, indicating they could provide early warning information against bacterial infection. The findings in our study will contribute to better understanding the biological processes and important roles of SpHSPs involved in defending against pathogenic bacterial challenge. Full article

(This article belongs to the Topic Animal Diseases in Agricultural Production Systems)

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11 pages, 1484 KiB

Open AccessArticle

Phosphorus Absorption and Excretion in Hybrid Sturgeon (Huso dauricus♀ X Acipenser schrenckii♂) Intubated with Different Ca/P Ratios

by Jiali Jin, Zhipeng Chu, Rui Ruan, Wei Liu, Xihua Chen and Chuangju Li

Fishes 2022, 7(3), 138; https://doi.org/10.3390/fishes7030138 - 10 Jun 2022

Cited by 3 | Viewed by 1464

Abstract

To study the effect of Ca/P ratio on the P and Ca absorption and excretion in hybrid sturgeon (Huso dauricus♀ X Acipenser schrenckii♂), five groups of fish were intubated with 100 mg P·kg⁻¹ BW with the Ca/P ratios [...] Read more.

To study the effect of Ca/P ratio on the P and Ca absorption and excretion in hybrid sturgeon (Huso dauricus♀ X Acipenser schrenckii♂), five groups of fish were intubated with 100 mg P·kg⁻¹ BW with the Ca/P ratios of 0:1, 0.25:1, 0.5:1, 1:1, and 2:1. Plasma P concentrations were significantly elevated at Ca/P ratios below 2:1, and the highest value was obtained at Ca/P ratio of 0.5:1. Plasma Ca content was significantly increased at the highest Ca/P ratio. Urine P excretion rate in the fish intubated with Ca/P ratio of 0.5:1 was significantly higher than that of the groups with Ca/P ratios of 0:1 and 2:1. The highest urea excretion rates were observed at Ca/P ratio of 0.5:1 and 1:1. The total P excretion at 48 h post intubation reached about 30 mg·kg⁻¹ BW, which was recorded for the group with Ca/P ratio of 0.5:1. The present study showed that P absorption efficiency was improved in hybrid sturgeon at Ca/P ratio of 0.5:1, indicating that P inclusion level in sturgeon feed can be further optimized to reduce dietary P input and lower the excessive undigested P discharge into the rearing water. Full article

(This article belongs to the Section Nutrition and Feeding)

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14 pages, 1210 KiB

Open AccessArticle

Incorporation of Fructooligosaccharides in Diets Influence Growth Performance, Digestive Enzyme Activity, and Expression of Intestinal Barrier Function Genes in Tropical Gar (Atractosteus tropicus) Larvae

by Graciela M. Pérez-Jiménez, Emyr Saul Peña-Marín, Claudia I. Maytorena-Verdugo, Cesar Antonio Sepúlveda-Quiroz, Luis Daniel Jiménez-Martínez, Susana De la Rosa-García, Gloria Gertrudys Asencio-Alcudia, Rafael Martínez, Dariel Tovar-Ramírez, Mario A. Galaviz, Talhia Martínez-Burguete, Carlos A. Alvarez-González and Carina Shianya Alvarez-Villagomez

Fishes 2022, 7(3), 137; https://doi.org/10.3390/fishes7030137 - 10 Jun 2022

Cited by 6 | Viewed by 2063

Abstract

This study was conducted to investigate the effects of dietary fructooligosaccharides (FOS) on the growth, survival rate, digestive enzyms activity, and the expression of intestinal barrier function genes in tropical gar (Atractosteus tropicus) larvae. A total of 960 larvae (0.030 ± [...] Read more.

This study was conducted to investigate the effects of dietary fructooligosaccharides (FOS) on the growth, survival rate, digestive enzyms activity, and the expression of intestinal barrier function genes in tropical gar (Atractosteus tropicus) larvae. A total of 960 larvae (0.030 ± 0.006 g) were fed three diets supplemented with increasing FOS concentrations (2.5, 5, and 7.5 g kg⁻¹) and a control diet for 15 days. Results revealed that a 7.5 g kg⁻¹ FOS supplementation improved weight gain, specific growth rate, and survival rate (p < 0.05). Furthermore, 5 g kg⁻¹ FOS supplementation increased alkaline protease and amylase activities and induced an upregulation of the claudin-17 gene expression (p < 0.05). Meanwhile, the inclusion of 7.5 g kg⁻¹ FOS induced the upregulation of mucin 2 (muc-2), and the tight junction genes zo-2 and claudin-3 (p < 0.05). In addition, 2.5, 5, and 7.5 g kg⁻¹ FOS promoted the downregulation of the claudin-15 gene expression (p < 0.05). At the same time, FOS inclusion did not increase the pro-inflammatory cytokine il-8 expression. We can conclude that 7.5 g kg⁻¹ FOS supplementation improves growth performance, survival rate, and digestive capacity, and could contribute to the reinforcement of the intestinal barrier function of Tropical gar larvae. Full article

(This article belongs to the Special Issue Gut Microbiota in Fish and Shellfish)

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16 pages, 4737 KiB

Open AccessFeature PaperArticle

Assessing the Stock Dynamics of Elasmobranchii off the Southern Coast of Sicily by Using Trawl Survey Data

by Fabio Falsone, Vita Gancitano, Michele Luca Geraci, Giacomo Sardo, Danilo Scannella, Fabrizio Serena, Sergio Vitale and Fabio Fiorentino

Fishes 2022, 7(3), 136; https://doi.org/10.3390/fishes7030136 - 07 Jun 2022

Cited by 13 | Viewed by 2723

Abstract

Elasmobranchii (sharks and rays), which have peculiar and vulnerable life-history traits, are highly threatened by fishing activities. Indeed, between 53% and 71% of Mediterranean elasmobranch species are at risk of extinction. In this context, using the abundance MSY (AMSY) model, the present study [...] Read more.

Elasmobranchii (sharks and rays), which have peculiar and vulnerable life-history traits, are highly threatened by fishing activities. Indeed, between 53% and 71% of Mediterranean elasmobranch species are at risk of extinction. In this context, using the abundance MSY (AMSY) model, the present study provides an assessment of 20 batoids and 16 shark species in the Strait of Sicily, sampled during a bottom trawl survey from 1995 to 2020. Overall, the outputs underline a progressively improving condition for shark and ray assemblages of both shelf and eurybathic zones. As for slope-dwelling species, a horseshoe-shaped dynamic, characterized by a progressive decrease in relative harvesting pressure and an increase in relative biomass followed by an increase in fishing pressure and decrease in biomass, was detected. The dynamics of the Elasmobranchii living in the Strait of Sicily appear to be affected by changes in the fishing patterns of trawlers, showing a shift from shallow water to bathyal fishing grounds and targeting deep-water red shrimp. In this context, it seems wise to limit the impact of deep-water fisheries on Elasmobranchii by reducing fishing efforts and implementing ad hoc management measures aimed at safeguarding these vulnerable species. Full article

(This article belongs to the Special Issue Cartilaginous Fishes: Stock Assessment and Population Dynamics)

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17 pages, 1979 KiB

Open AccessEditor’s ChoiceArticle

Regional Population Structure of the European Eel at the Southern Limit of Its Distribution Revealed by Otolith Shape Signature

by Ana Moura, Ester Dias, Rodrigo López and Carlos Antunes

Fishes 2022, 7(3), 135; https://doi.org/10.3390/fishes7030135 - 07 Jun 2022

Cited by 6 | Viewed by 3271

Abstract

Given the European eel population’s marked decrease since the 1980s, it has become urgent to collect information describing its regional population structure to improve management plans. The Minho River (NW-Portugal, SW-Europe) is an important basin for the eel at the southern limit of [...] Read more.

Given the European eel population’s marked decrease since the 1980s, it has become urgent to collect information describing its regional population structure to improve management plans. The Minho River (NW-Portugal, SW-Europe) is an important basin for the eel at the southern limit of its distribution, but the species is poorly described. Thus, we aimed to study the structure of the European eel population in the Minho River using otolith shape analysis, which has proven to be effective in discriminating fish groups experiencing different environmental conditions through ontogeny. Our results showed complete discrimination between the two main types of habitats studied (tributaries and estuaries). Otoliths of eels from the estuary were rectangular and elliptic, whereas in the tributaries they presented a more round and circular form. Eels collected in both habitats were mostly yellow-stage eels with a similar age range, but the eels from the tributaries showed smaller length-at-age and lower body condition than those collected in the estuary. Additionally, the sex ratio was skewed towards males in the tributaries and females in the estuary. This study reveals that there are at least two distinct groups of eels in this basin, likely with different development characteristics. Full article

(This article belongs to the Special Issue Otoliths and Their Applications in Fishery Science)

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15 pages, 1669 KiB

Open AccessArticle

Sporosarcina aquimarina MS4 Regulates the Digestive Enzyme Activities, Body Wall Nutrients, Gut Microbiota, and Metabolites of Apostichopus japonicus

by Hong Yi, Qinglu Bai, Ying Li, Honglei Zhan, Yujia Liu, Bingnan Liu and Jihui Wang

Fishes 2022, 7(3), 134; https://doi.org/10.3390/fishes7030134 - 07 Jun 2022

Cited by 3 | Viewed by 1616

Abstract

Sporosarcina aquimarina MS4 is a microecological preparation for overwintering Apostichopus japonicus, which has an immune regulation function, but its role in the nutritional regulation of A. japonicus is not clear. This study aimed to describe the effects of S. aquimarina MS4 on [...] Read more.

Sporosarcina aquimarina MS4 is a microecological preparation for overwintering Apostichopus japonicus, which has an immune regulation function, but its role in the nutritional regulation of A. japonicus is not clear. This study aimed to describe the effects of S. aquimarina MS4 on the growth, digestion, and body wall nutrition of A. japonicus through feeding experiments and to discuss the potential mechanism of S. aquimarina MS4 regulating gut function through the detection of gut microbiota and metabolites. After 60 days of culture, the growth performance of A. japonicus fed S. aquimarina MS4 (10⁸ cfu/g) significantly improved, and the content of polysaccharide, leucine, phenylalanine, lysine, and docosahexaenoic acid in the body wall significantly increased. Gut microbiota analysis showed that although Proteobacteria, Verrucomicrobia, Firmicutes, and Bacteroidetes were the predominant phyla in all the sea cucumbers, Haloferula and Rubritalea showed significant difference between the group fed with or without S. aquimarina MS4. Metabolomics analysis showed that differential metabolites in the gut were mainly enriched in amino acid metabolism and lipid metabolism. The association analysis of differential metabolites and microbiota showed that the production of some differential metabolites was significantly related to differential microorganisms, which improved the understanding of the function of microorganisms and their roles in the gut of A. japonicus. This study reveals the life activities such as growth and metabolism of A. japonicus, and it provides support for the functional study of the gut microbiome of A. japonicus. Full article

(This article belongs to the Section Nutrition and Feeding)

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15 pages, 1753 KiB

Open AccessFeature PaperArticle

The Use of Cinnamon Essential Oils in Aquaculture: Antibacterial, Anesthetic, Growth-Promoting, and Antioxidant Effects

by Guerino Bandeira Junior, Adriane Erbice Bianchini, Carine de Freitas Souza, Sharine Nunes Descovi, Liana da Silva Fernandes, Lenise de Lima Silva, Juliana Felipetto Cargnelutti and Bernardo Baldisserotto

Fishes 2022, 7(3), 133; https://doi.org/10.3390/fishes7030133 - 06 Jun 2022

Cited by 8 | Viewed by 3530

Abstract

Cinnamon essential oils (EOs) are widely known for their pharmaceutical properties; however, studies investigating the use of these EOs in aquaculture are scarce. The aims of this study were to evaluate the anesthetic effect of bathing silver catfish (Rhamdia quelen) with [...] Read more.

Cinnamon essential oils (EOs) are widely known for their pharmaceutical properties; however, studies investigating the use of these EOs in aquaculture are scarce. The aims of this study were to evaluate the anesthetic effect of bathing silver catfish (Rhamdia quelen) with Cinnamomum cassia EO (CCEO) and its nanoemulsion (NCCEO); the growth-promoting and antioxidant effects of dietary supplementation with CCEO in silver catfish; and the in vitro antibacterial effect of CCEO, NCCEO, and Cinnamomum zeylanicum EO (CZEO) against bacteria isolated from diseased silver catfish. The two cinnamon EOs showed promising antibacterial activity, which was potentiated by the nanoemulsion. CCEO showed satisfactory anesthetic activity in silver catfish, and its nanoemulsion intensified the sedative activity. Supplementation of 1.0 mL CCEO per kg of diet for 60 days increased weight, length, and weight gain when compared to the control group, evidencing the growth-promoting activity of this EO. Dietary supplementation of CCEO for 30 and 60 days also showed an antioxidant effect, as it decreased levels of thiobarbituric acid reactive species and increased the superoxide dismutase activity in the liver of silver catfish. Therefore, cinnamon EOs have a promising use in aquaculture. Full article

(This article belongs to the Special Issue Antimicrobials and Their Natural Alternatives—From Molecular Insights to On-Farm Interventions in Aquaculture)

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14 pages, 2619 KiB

Open AccessEditor’s ChoicePerspective

Nutrients and Bioactive Compounds in Seafood: Quantitative Literature Research Analysis

by Alessandra Durazzo, Gabriella Di Lena, Paolo Gabrielli, Antonello Santini, Ginevra Lombardi-Boccia and Massimo Lucarini

Fishes 2022, 7(3), 132; https://doi.org/10.3390/fishes7030132 - 05 Jun 2022

Cited by 6 | Viewed by 7803

Abstract

This perspective presents current and updated advances in research on nutrients and bioactive compounds in seafood. It is based on a literature quantitative research analysis approach. The main features of seafood components are introduced. This perspective aims at providing a current framework that [...] Read more.

This perspective presents current and updated advances in research on nutrients and bioactive compounds in seafood. It is based on a literature quantitative research analysis approach. The main features of seafood components are introduced. This perspective aims at providing a current framework that relates nutrients, bioactive compounds, and seafood in a novel integrated and multidisciplinary manner, highlighting the current knowledge, the main research lines, and emerging strategies. The literature search was carried out by means of the Scopus database, and 22,542 documents were retrieved in the period from 1932 to 2024. Particularly, from the perspective of nutrition and health outputs, the main terms correlated with research on the relationship between seafood and nutritional and bioactive components, and the main existing research lines focused on this topic, were identified. The top recurring keywords were human/s, female, diet, nutrition, fish, male, adult, food intake. Full article

(This article belongs to the Section Nutrition and Feeding)

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19 pages, 685 KiB

Open AccessReview

Sub-Saharan Africa Freshwater Fisheries under Climate Change: A Review of Impacts, Adaptation, and Mitigation Measures

by Rodney Tatenda Muringai, Paramu Mafongoya and Romano Trent Lottering

Fishes 2022, 7(3), 131; https://doi.org/10.3390/fishes7030131 - 02 Jun 2022

Cited by 7 | Viewed by 4020

Abstract

Sub-Saharan Africa’s freshwater fisheries contribute significantly to the livelihoods and food security of millions of people within the region. However, freshwater fisheries are experiencing multiple anthropogenic stressors such as overfishing, illegal fishing, pollution, and climate change. There is a substantial body of literature [...] Read more.

Sub-Saharan Africa’s freshwater fisheries contribute significantly to the livelihoods and food security of millions of people within the region. However, freshwater fisheries are experiencing multiple anthropogenic stressors such as overfishing, illegal fishing, pollution, and climate change. There is a substantial body of literature on the effects of climate change on freshwater fisheries in Sub-Saharan Africa. This study reviews the existing literature and highlights the effects of climate change on freshwater fisheries, the adaptation strategies of fishery-dependent households in response to the effects, and fisheries’ management and mitigation efforts in the face of climate change. The general effects of climate change on freshwater environments include warming water temperatures, increased stratification, modified hydrological processes, and increased pollutants. These effects adversely affect the physiological processes of fish and the overall wellbeing of fishery-dependent people. To cope with the effects of fluctuating fishery resources due to climate change, fishery-dependent people have adopted several adaptation strategies including livelihood diversification, changing their fishing gear, increasing their fishing efforts, and targeting new species. Several management attempts have been made to enhance the sustainability of fishery resources, from local to regional levels. This study recommends the participation of the resource users in the formulation of policies aimed at promoting climate change adaptation and the resilience of freshwater fisheries for sustainable development. Full article

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

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10 pages, 1440 KiB

Open AccessArticle

Cloning of Grass Carp Chemokine XC Receptor 1 (XCR1) Gene and Evaluation of Its Expression in Various Organs after GCRV Infection

by Hailuo Yu, Yi Liu, Tiaoyi Xiao, Hongquan Wang and Baohong Xu

Fishes 2022, 7(3), 130; https://doi.org/10.3390/fishes7030130 - 31 May 2022

Viewed by 1591

Abstract

Interaction between the chemokine receptor XCR1 and its ligand is closely related to the immune function in animals; however, there are only a few reports on role of XCR1 in the immune system of fish. We aimed to analyze the expression of XCR1 [...] Read more.

Interaction between the chemokine receptor XCR1 and its ligand is closely related to the immune function in animals; however, there are only a few reports on role of XCR1 in the immune system of fish. We aimed to analyze the expression of XCR1 in various organs or tissues of grass carp before and after Grass Carp Reovirus (GCRV) infection to better understand the function of XCR1 in resistance to GCRV infection. We cloned and sequenced the cDNA of grass carp XCR1 and analyzed the molecular structure of XCR1 based its amino acid sequence. Further, we analyzed the relative expression levels of XCR1 in different organs or tissues of male parent grass carp with GCRV resistance (P1) and their first-generation offspring (F1) before and after GCRV infection. Our results show that the total length of cDNA of the grass carp XCR1 gene is 1659 bp and encodes 365 amino acids. XCR1 contains seven conserved transmembrane helical domains. The homologous tertiary structure of XCR1 is similar to its homologs in other species. After artificial GCRV infection, there were significant differences in the expression of the grass carp XCR1 gene in different tissues, at different time points, and between P1 and F1 fish. These results will contribute to our understanding of the role of XCR1 in fish immune responses and contribute to the development of GCRV-resistant grass carp. Full article

(This article belongs to the Special Issue Diseases in Fish and Shellfish)

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13 pages, 3133 KiB

Open AccessArticle

The miR-200 Family Targeting amh Affects the Gonadal Development of Japanese Flounder

by Haoran Zhang, Kun Li, Fayang Zhang, Jikui Wu and Junling Zhang

Fishes 2022, 7(3), 129; https://doi.org/10.3390/fishes7030129 - 31 May 2022

Cited by 1 | Viewed by 1599

Abstract

Four members of the miR-200 family in Japanese flounder (Paralichthys olivaceus) have sex-biased expression patterns, but their target genes and how they work in the development of the gonads are rarely known. Anti-Müllerian hormone (AMH) can inhibit the development of Muller’s [...] Read more.

Four members of the miR-200 family in Japanese flounder (Paralichthys olivaceus) have sex-biased expression patterns, but their target genes and how they work in the development of the gonads are rarely known. Anti-Müllerian hormone (AMH) can inhibit the development of Muller’s duct in female mammals and regulate the formation of gametes after sexual maturity. There is no Muller’s duct in teleosts, but the amh gene still exists. Knockout of amh results in sex reversal from male to female. Therefore, it is essential to explore the relationship between the miR-200 family and amh to clarify what role miR-200 plays in the development of the gonads. In Japanese flounder, the two binding sites for the miR-200 family in the 3′UTR of amh were found through bioinformatic prediction. Double luciferase and green fluorescent protein reporter experiments demonstrated amh to be directly targeted by miR-200a and miR-200b. Moreover, miR-200a and miR-200b reduced the expression of amh through site 1 rather than site 2. To explore the regulatory role of miR-200a in gonadal development, we further overexpressed miR-200a in the primary Sertoli cells of the testis. With the overexpression of miR-200a, the expression of amh decreased, while the expression of the other two male sex-related genes, dmrt1 (doublesex and mab-3 related transcription factor 1) and gsdf (diagonal soma driven factor), increased significantly. This result indicates that the miR-200 family regulates the gonadal differentiation and development by targeting amh in Japanese flounder. Full article

(This article belongs to the Section Genetics and Biotechnology)

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9 pages, 1080 KiB

Open AccessArticle

Taste Attributes of the “June Hairy Crab” Juveniles of Chinese Mitten Crab (Eriocheir sinensis) in Yangcheng Lake, China—A Pilot Study

by Hongbo Liu, Junren Xue, Jing Tang, Tao Jiang, Xiubao Chen and Jian Yang

Fishes 2022, 7(3), 128; https://doi.org/10.3390/fishes7030128 - 31 May 2022

Cited by 3 | Viewed by 2484

Abstract

This is the first report on the use of a taste sensing system to quantitatively evaluate the taste attributes of two groups of native “June hairy crab” juveniles (commonly referred to as “Liu-Yue-Huang”) of the Chinese mitten crab (Eriocheir Sinensis H. Milne [...] Read more.

This is the first report on the use of a taste sensing system to quantitatively evaluate the taste attributes of two groups of native “June hairy crab” juveniles (commonly referred to as “Liu-Yue-Huang”) of the Chinese mitten crab (Eriocheir Sinensis H. Milne Edwards, 1853) from a net enclosure culture area in Yangcheng Lake (lake culture) and aquaculture ponds near the lake (pond culture). We showed that umami was the predominant basic taste of steamed June hairy crabs, followed by bitterness and astringency. The intensity value of saltiness was aberrant and could not be determined using this system. The average values of aftertaste-U reached 8.7 and 10.7 in the male June hairy crabs from the lake and pond cultures, respectively, which was significantly higher than their respective aftertaste-B and aftertaste-A values (p < 0.01). Female crabs did not have aftertaste-B, while their aftertaste-U was significantly higher than aftertaste-A (p < 0.01). Although principal component analysis and linear discriminant analysis were not able to completely distinguish among crabs from different cultures, they could robustly distinguish between male and female crabs. Full article

(This article belongs to the Section Sustainable Aquaculture)

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12 pages, 1697 KiB

Open AccessArticle

Inclusion of Mannan-Oligosaccharides in Diets for Tropical Gar Atractosteus tropicus Larvae: Effects on Growth, Digestive Enzymes, and Expression of Intestinal Barrier Genes

by Claudia I. Maytorena-Verdugo, Emyr S. Peña-Marín, Carina S. Alvarez-Villagómez, Graciela M. Pérez-Jiménez, César A. Sepúlveda-Quiroz and Carlos A. Alvarez-González

Fishes 2022, 7(3), 127; https://doi.org/10.3390/fishes7030127 - 31 May 2022

Cited by 6 | Viewed by 1962

Abstract

Mannan-oligosaccharides (MOS) are non-digestible carbohydrates, and their use in aquaculture as prebiotics is well documented. The objective of this work was to test whether MOS supplemented in the diet of A. tropicus larvae (2, 4, and 6 g kg⁻¹) influence [...] Read more.

Mannan-oligosaccharides (MOS) are non-digestible carbohydrates, and their use in aquaculture as prebiotics is well documented. The objective of this work was to test whether MOS supplemented in the diet of A. tropicus larvae (2, 4, and 6 g kg⁻¹) influence growth parameters, the activity of digestive enzymes, and the expression of genes related to the intestinal barrier. The highest total length was observed in larvae fed 6 g kg⁻¹ MOS compared to control larvae. Trypsin activity increased with the addition of MOS to the diets, but leucine aminopeptidase activity only increased with 6 g kg⁻¹ MOS. Lipase and α-amylase activities increased in larvae fed with 2 and 4 g kg⁻¹ MOS. The expression of zo-2 was higher with the 6 g kg⁻¹ MOS treatment. The cl-3 transcripts were lower with 2 g kg⁻¹ MOS but higher with 6 g kg⁻¹ MOS. All tested concentrations of MOS increased the expression of muc-2. In this study, incorporating mannan-oligosaccharides into the diet of A. tropicus larvae had a positive effect, and the concentration of 6 g kg⁻¹ produced the best results. Therefore, including this prebiotic in the diets for the culture of A. tropicus larvae is suitable. Full article

(This article belongs to the Special Issue Advances in Nutrition and Feeding of Fish)

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8 pages, 784 KiB

Open AccessCommunication

Suspended Structures Reduce Variability of Group Risk-Taking Responses of Dicentrarchus labrax Juvenile Reared in Tanks

by Pablo Arechavala-Lopez, Samira Nuñez-Velazquez, Carlos Diaz-Gil, Guillermo Follana-Berná and João L. Saraiva

Fishes 2022, 7(3), 126; https://doi.org/10.3390/fishes7030126 - 31 May 2022

Cited by 2 | Viewed by 2293

Abstract

Structural enrichment is considered a useful tool to improve the welfare conditions of captive fish by deliberately increasing the physical heterogeneity and complexity of captivity environments. However, the potential effects of structural enrichment on the stress response at the group level and on [...] Read more.

Structural enrichment is considered a useful tool to improve the welfare conditions of captive fish by deliberately increasing the physical heterogeneity and complexity of captivity environments. However, the potential effects of structural enrichment on the stress response at the group level and on social interactions have not been well studied yet. In this study, we demonstrate that suspended vertical structures (U-shaped ropes) can reduce behavioural variability among fish groups (tank level) of European seabass (Dicentrarchus labrax) juveniles. Differences in behavioural responses during group risk-taking tests (e.g., number of passes per fish) between treatments were detected, and these responses in seabass in enriched captive conditions were more homogeneous among tanks compared to fish from non-enriched tanks. These results suggest a positive effect of the structural enrichment on social stabilisation and response to stressful events at the tank level in seabass. However, further research is still needed to improve the knowledge of the potential effects of structural enrichment on fish welfare and aquaculture management, considering different enrichment designs, intensities, and strategies according to farming conditions, biological needs, and preferences of the fish species and life-stage reared in captivity. Full article

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

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8 pages, 1716 KiB

Open AccessArticle

Infectivity and Transmissibility of Acute Hepatopancreatic Necrosis Disease Associated Vibrio parahaemolyticus in Frozen Shrimp Archived at −80 °C

by Chorong Lee, Hye Jin Jeon, Bum Keun Kim, Seong-Kyoon Choi, Sumi Kim, Gwang Il Jang, Ji Hyung Kim and Jee Eun Han

Fishes 2022, 7(3), 125; https://doi.org/10.3390/fishes7030125 - 30 May 2022

Cited by 1 | Viewed by 2204

Abstract

Acute hepatopancreatic necrosis disease (AHPND) caused by Vibrio parahaemolyticus (Vp_AHPND) has been reported in commodity shrimp, but the potential risk of its global spread via frozen shrimp in the shrimp trade is yet to be fully explored. We hypothesized that [...] Read more.

Acute hepatopancreatic necrosis disease (AHPND) caused by Vibrio parahaemolyticus (Vp_AHPND) has been reported in commodity shrimp, but the potential risk of its global spread via frozen shrimp in the shrimp trade is yet to be fully explored. We hypothesized that frozen shrimp with AHPND could be a source of Vp_AHPND transmission; thus, the infectivity of frozen shrimp with AHPND was evaluated using a shrimp bioassay. To prepare infected frozen shrimp, 12 Penaeus vannamei (average weight, 2 g) were exposed to Vp_AHPND by immersion in water with a Vp_AHPND concentration of 1.55 × 10⁷ CFU mL⁻¹; once dead, the shrimp were stored at −80 °C for further analysis. After two weeks, a PCR assay was used to confirm AHPND positivity in frozen shrimp (n = 2), and Vp_AHPND was reisolated from the hepatopancreases of these shrimp. For the infectivity test, 10 P. vannamei (average weight, 4 g) were fed with the hepatopancreases of Vp_AHPND -infected frozen shrimp (n = 10). After feeding, 70% of the shrimp died within 118 h, and the presence of Vp_AHPND was confirmed using a PCR assay and histopathology examination; moreover, Vp_AHPND was successfully reisolated from the hepatopancreases of the dead shrimp. We are the first to evaluate the potential transmissibility of Vp_AHPND in frozen shrimp, and our results suggest that frozen shrimp with AHPND are a potential source of disease spreading between countries during international trade. Full article

(This article belongs to the Special Issue Diseases in Fish and Shellfish)

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10 pages, 781 KiB

Open AccessArticle

Long-Term Change of a Fish-Based Index of Biotic Integrity for a Semi-Enclosed Bay in the Beibu Gulf

by Li Su, Youwei Xu, Yongsong Qiu, Mingshuai Sun, Kui Zhang and Zuozhi Chen

Fishes 2022, 7(3), 124; https://doi.org/10.3390/fishes7030124 - 30 May 2022

Cited by 5 | Viewed by 1830

Abstract

The Beibu Gulf in the northwestern South China Sea is one of the world’s most productive fishing grounds, yet its biotic resources appear to be in rapid decline because of overexploitation. Assessments of the health status of the fisheries’ resources in the gulf [...] Read more.

The Beibu Gulf in the northwestern South China Sea is one of the world’s most productive fishing grounds, yet its biotic resources appear to be in rapid decline because of overexploitation. Assessments of the health status of the fisheries’ resources in the gulf provide a foundation for their conservation and management. As fish accounted for 84% to 97% of the total catch in the Beibu Gulf in the period 1962–2017, a Fish-based Index of Biotic Integrity (F-IBI) was developed for the Beibu Gulf, and data from otter trawl surveys during the period 1962–2017 were used to measure variations in the fish community. The assessment revealed a generally downward trend in total fish catch density (kg/km²), catch density of 12 traditional commercial demersal fish species, and percentage of nektonic-feeding species, but an upward trend for the percentage of fishes with a planktivorous or detritus diet, percentage of pelagic species, and percentage of the dominant species. The dominant species varied greatly over the 50 year period and showed a tendency towards small-sized species. The synthetic F-IBI variable showed a downward trend and has indicated a ‘fair’ state since 1998. The decline in the F-IBI over the last three decades suggests that anthropogenic disturbances, especially overfishing, have had a serious impact on the fish community of the Beibu Gulf. The F-IBI is currently at risk of becoming ‘poor.’ Consequently, we suggest that rigid and enforceable fishery management measures should be taken by both China and Vietnam to prevent further deterioration of the fisheries’ resources in the gulf. Full article

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16 pages, 1428 KiB

Open AccessArticle

Fidelity to Natal Tributary Streams by Kokanee Following Introduction to a Large Oligotrophic Reservoir

by J. Mark Shrimpton, Paige W. Breault and Luc A. Turcotte

Fishes 2022, 7(3), 123; https://doi.org/10.3390/fishes7030123 - 30 May 2022

Cited by 2 | Viewed by 1768

Abstract

The WAC Bennett Dam was completed in 1968 and impounded the Upper Peace River to form the Williston Reservoir in north central British Columbia. In 1990, an enhancement project was initiated to stock Columbia River Kokanee (non-anadromous Sockeye Salmon; Oncorhynchus nerka) from [...] Read more.

The WAC Bennett Dam was completed in 1968 and impounded the Upper Peace River to form the Williston Reservoir in north central British Columbia. In 1990, an enhancement project was initiated to stock Columbia River Kokanee (non-anadromous Sockeye Salmon; Oncorhynchus nerka) from southeastern British Columbia into tributary streams that drained into regions of the reservoir that were accessible by anglers. The current distribution of spawning Columbia-origin Kokanee in the Williston Reservoir watershed, however, does not reflect the locations where these fish were initially stocked and suggests extensive straying. Whether or not Kokanee will develop fidelity to specific spawning locations is not known, but it is important information to effectively manage these introduced fish. We used otolith microchemistry to estimate fidelity to natal streams by Columbia-origin Kokanee in the Williston Reservoir. Otolith elemental signatures for the region of the otolith that formed during the larval period and characterized the natal redd environment showed considerable variation among samples. Natal signatures tended to cluster for each river but not for all spawners, suggesting elemental signatures from other rivers. Homing to one of the four natal streams we examined was classified to be 73% based on linear discriminant analysis, although variation in the elemental signatures within each group suggests that homing by Kokanee to specific natal streams may be as low as 55%. Based on similarity of water elemental signatures for tributaries within large rivers, however, the proportion of fish that returned to their general region was likely higher and estimated to be approximately 83%. The result of regional homing could be reproductive isolation and adaptation to local conditions. It is unclear, however, if the current estimated level of straying will limit genetic differentiation and prevent local adaptation. Full article

(This article belongs to the Special Issue Otoliths and Their Applications in Fishery Science)

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11 pages, 1441 KiB

Open AccessArticle

The Effect of Hormonal Treatment on Selected Sperm Quality Parameters and Sex Steroids in Tropical Cyprinid Bala Shark Balantiocheilos melanopterus

by Peter Podhorec, Jindřiška Knowles, Jakub Vysloužil, Sergii Boryshpolets, Anatolii Sotnikov, Martina Holická, Jan Kouřil and Borys Dzyuba

Fishes 2022, 7(3), 122; https://doi.org/10.3390/fishes7030122 - 30 May 2022

Cited by 2 | Viewed by 2039

Abstract

Hormone treatments are routinely employed with bala shark Balantiocheilos melanopterus male broodstock to stimulate the production of high-quality sperm. In the current trial, three spermiation-inducing treatments were evaluated: 20 μg/kg body weight (BW) recombinant hCG; 20 μg/kg BW [D-Ala⁶, Pro⁹ [...] Read more.

Hormone treatments are routinely employed with bala shark Balantiocheilos melanopterus male broodstock to stimulate the production of high-quality sperm. In the current trial, three spermiation-inducing treatments were evaluated: 20 μg/kg body weight (BW) recombinant hCG; 20 μg/kg BW [D-Ala⁶, Pro⁹, NEt]- gonadotropin-releasing hormone (GnRHa) with 20 mg/kg BW metoclopramide; and poly(lactic-co-glycolic acid) (PLGA) microparticles with slow release of 10 μg/kg BW GnRHa. A 0.9% saline AS negative control was also included. Administration of the GnRHa through the form of slow release of PLGA microparticles 24 h after treatment resulted in a significantly higher sperm volume, motility percentage, and total sperm count compared to the control. Injection of GnRHa with metoclopramide induced sperm parameters that did not differ from the control, with the exception of motility percentage. The lowest potency to induce spermiation in bala sharks was in the treatment with recombinant hCG. Both PLGA microparticles and GnRHa with metoclopramide significantly increased blood plasma concentrations of testosterone and 11-ketotestosterone compared to the control. The PLGA microparticle system with continuous release of 10 μg/kg BW GnRHa was the most effective treatment in inducing spermiation in bala sharks. Full article

(This article belongs to the Section Physiology and Biochemistry)

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11 pages, 5038 KiB

Open AccessEditor’s ChoiceArticle

DeepOtolith v1.0: An Open-Source AI Platform for Automating Fish Age Reading from Otolith or Scale Images

by Dimitris V. Politikos, Nikolaos Sykiniotis, Georgios Petasis, Pavlos Dedousis, Alba Ordoñez, Rune Vabø, Aikaterini Anastasopoulou, Endre Moen, Chryssi Mytilineou, Arnt-Børre Salberg, Archontia Chatzispyrou and Ketil Malde

Fishes 2022, 7(3), 121; https://doi.org/10.3390/fishes7030121 - 29 May 2022

Cited by 3 | Viewed by 3905

Abstract

Every year, marine scientists around the world read thousands of otolith or scale images to determine the age structure of commercial fish stocks. This knowledge is important for fisheries and conservation management. However, the age-reading procedure is time-consuming and costly to perform due [...] Read more.

Every year, marine scientists around the world read thousands of otolith or scale images to determine the age structure of commercial fish stocks. This knowledge is important for fisheries and conservation management. However, the age-reading procedure is time-consuming and costly to perform due to the specialized expertise and labor needed to identify annual growth zones in otoliths. Effective automated systems are needed to increase throughput and reduce cost. DeepOtolith is an open-source artificial intelligence (AI) platform that addresses this issue by providing a web system with a simple interface that automatically estimates fish age by combining otolith images with convolutional neural networks (CNNs), a class of deep neural networks that has been a dominant method in computer vision tasks. Users can upload otolith image data for selective fish species, and the platform returns age estimates. The estimates of multiple images can be exported to conduct conclusions or further age-related research. DeepOtolith currently contains classifiers/regressors for three fish species; however, more species will be included as related work on ageing will be tested and published soon. Herein, the architecture and functionality of the platform are presented. Current limitations and future directions are also discussed. Overall, DeepOtolith should be considered as the first step towards building a community of marine ecologists, machine learning experts, and stakeholders that will collaborate to support the conservation of fishery resources. Full article

(This article belongs to the Special Issue Otoliths and Their Applications in Fishery Science)

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9 pages, 2387 KiB

Open AccessEditor’s ChoiceCommunication

Basic Intersexuality (Abnormal Hermaphroditism) in the Blackmouth Catshark, Galeus melastomus, (Rafinesque, 1810), from the Southern Tyrrhenian Sea (Central Mediterranean Sea)

by Claudio D’Iglio, Marco Albano, Sergio Famulari, Nunziacarla Spanò, Paola Rinelli, Serena Savoca and Gioele Capillo

Fishes 2022, 7(3), 120; https://doi.org/10.3390/fishes7030120 - 28 May 2022

Cited by 4 | Viewed by 2779

Abstract

The present paper represents the first description of abnormal hermaphroditism in Galeus melastomus (Rafinesque, 1810). The black mouth cat shark specimen, collected in summer from southern Tyrrhenian Sea at the entrance of Salerno gulf, showed a basic intersexuality characterized by the presence of [...] Read more.

The present paper represents the first description of abnormal hermaphroditism in Galeus melastomus (Rafinesque, 1810). The black mouth cat shark specimen, collected in summer from southern Tyrrhenian Sea at the entrance of Salerno gulf, showed a basic intersexuality characterized by the presence of male secondary and female primary sexual characters. The reproductive system has been described with an accurate morphological analysis, also including a histological assessment of oocytes. Results showed the presence of only right clasper, not exceeding the pelvic fin in length, with the absence of internal males’ sexual organs. Concerning the female primary characters, the analysis of histological assessment showed the structure of mature oocyte, confirming the maturity stage of a mature female in active extruding stage, as highlighted by the macroscopic morphological analysis. Despite in many marine organisms’ hermaphroditism is a physiological condition showed by specimens during their lifecycle, in Elasmobranchs this is considered an abnormal condition, with some exceptions. The lack of information on hermaphroditism in elasmobranchs form the Mediterranean Sea requires an increase of scientific community’s attention, improving the knowledge on the reproductive biology of this sensitive taxon. This is essential to enhance the conservation of elasmobranchs populations in the entire Mediterranean basin. Full article

(This article belongs to the Section Biology and Ecology)

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13 pages, 3498 KiB

Open AccessArticle

Isolation, Identification and Characteristics of Aeromonas caviae from Diseased Largemouth Bass (Micropterus salmoides)

by Mingyang Xue, Zidong Xiao, Yiqun Li, Nan Jiang, Wenzhi Liu, Yan Meng, Yuding Fan, Lingbing Zeng and Yong Zhou

Fishes 2022, 7(3), 119; https://doi.org/10.3390/fishes7030119 - 28 May 2022

Cited by 9 | Viewed by 3687

Abstract

The largemouth bass (Micropterus salmoides) is one of the most economically valuable fish species in China. In this study, a bacterial pathogen was isolated from the internal organs of diseased M. salmoides, and the strain was named WH21406. This isolate [...] Read more.

The largemouth bass (Micropterus salmoides) is one of the most economically valuable fish species in China. In this study, a bacterial pathogen was isolated from the internal organs of diseased M. salmoides, and the strain was named WH21406. This isolate was identified as Aeromonas caviae on the basis of its morphology, biochemical features and 16S rDNA phylogenetic analysis. Four virulence genes related to pathogenicity, namely, flagella (fla), elastase (ela), haemolysin (hly) and aerolysin (aer), were detected in this isolate. The median lethal dosage (LD50) of A. caviae WH21406 for M. salmoides was calculated to be 3.46 × 10⁵ CFU mL⁻¹. The histopathological analysis showed obvious tissue damage in the gill, liver, kidney, spleen and gut of the diseased fish. The antibiotic susceptibility test demonstrated that strain WH21406 was highly sensitive to enrofloxacin, norfloxacin, streptomycin and amikacin. The results of this study provide a foundation for the diagnosis, prevention and treatment of A. caviae infection in M. salmoides. Full article

(This article belongs to the Special Issue Diseases in Fish and Shellfish)

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15 pages, 1357 KiB

Open AccessArticle

Functional Characterization and Molecular Marker Development of the Proenkephalin as Biomarker of Food Addiction in Food Habit Domestication of Mandarin Fish (Siniperca chuatsi)

by Yingcen Li, Yunliang Miao, Xufang Liang and Shan He

Fishes 2022, 7(3), 118; https://doi.org/10.3390/fishes7030118 - 27 May 2022

Cited by 2 | Viewed by 2057

Abstract

Proenkephalin (PENK), as the precursor of endogenous opioid enkephalin (ENK), is widely present in the nervous system and plays an important role in animal food addiction and rewarding behavior. In our study, we intend to study the functional characterization and molecular marker development [...] Read more.

Proenkephalin (PENK), as the precursor of endogenous opioid enkephalin (ENK), is widely present in the nervous system and plays an important role in animal food addiction and rewarding behavior. In our study, we intend to study the functional characterization and molecular marker development of the penk gene related to food habit domestication of mandarin fish. We found that the penk gene of mandarin fish had three types of endogenous opioid peptide sequences. Compared with other tissues, penk mRNA was highly expressed in the whole brain. Intracerebroventricular (ICV) injection of lysine or methionine significantly increased the expression of penk mRNA. The expression of penk mRNA in the brain of mandarin fish that could be easily domesticated from eating live prey fish to artificial diets was significantly higher than those that could not. After feeding with high-carbohydrate artificial diets, the expression of penk mRNA showed no significant difference between mandarin fish with hypophagia and those that still ate normally. A total of four single nucleotide polymorphisms (SNP) loci related to easy domestication toward eating artificial diets were screened from the mandarin fish population. Additionally, the TT genotype at one of the loci was significantly correlated with the food habit domestication of mandarin fish. Full article

(This article belongs to the Special Issue Advances in Nutrition and Feeding of Fish)

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9 pages, 633 KiB

Open AccessEditor’s ChoiceCommunication

Development of the First Microsatellite Multiplex PCR Panel for Meagre (Argyrosomus regius), a Commercial Aquaculture Species

by Antonio Vallecillos, Emilio María-Dolores, Javier Villa, Francisco Miguel Rueda, José Carrillo, Guillermo Ramis, Mohamed Soula, Juan Manuel Afonso and Eva Armero

Fishes 2022, 7(3), 117; https://doi.org/10.3390/fishes7030117 - 24 May 2022

Cited by 6 | Viewed by 2423

Abstract

In this study, a microsatellite-based multiplex PCR panel for meagre (Argyrosomus regius) was developed as a useful and single tool in parental assignment and population studies. Twenty-one specific and interspecific microsatellites from different aquaculture species of meagre (Argyrosomus regius), [...] Read more.

In this study, a microsatellite-based multiplex PCR panel for meagre (Argyrosomus regius) was developed as a useful and single tool in parental assignment and population studies. Twenty-one specific and interspecific microsatellites from different aquaculture species of meagre (Argyrosomus regius), Japanese meagre (A. japonicus), red drum (Sciaenops ocellatus) and yellow meagre (Acoupa weakfish) were assessed for genetic variability, allelic range and genotype reliability. Finally, a SuperMultiplex for Argyrosomus regius (SMAr) was designed with only the best eight microsatellite markers. The panel assessment was performed using a batch of brood stock from one company and a sample of 616 offspring. It was possible to assign 95% of the offspring to a single pair of parents using the exclusion method. It is therefore considered an easy procedure, and a powerful and low-cost tool for parental assignment to support companies’ breeding programs and to exchange information between research groups. Full article

(This article belongs to the Special Issue Population Genetics and Conservation of Fishes)

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20 pages, 1319 KiB

Open AccessEditor’s ChoiceArticle

Climate Risks and Opportunities of the Marine Fishery Industry: A Case Study in Taiwan

by Ching-Hsien Ho

Fishes 2022, 7(3), 116; https://doi.org/10.3390/fishes7030116 - 21 May 2022

Cited by 6 | Viewed by 2900

Abstract

As climate change and extreme weather intensify, forecasting natural environmental changes involves high uncertainty and variation. Planned policy changes and the ability of fisheries to withstand these changes and impacts are major challenges in regard to addressing future climate hazards in Taiwan. Taiwan’s [...] Read more.

As climate change and extreme weather intensify, forecasting natural environmental changes involves high uncertainty and variation. Planned policy changes and the ability of fisheries to withstand these changes and impacts are major challenges in regard to addressing future climate hazards in Taiwan. Taiwan’s geographic location is favourable for the marine fishery industry, which is an important primary industry and a source of animal protein for residents of Taiwan. Recently, both long-term climate change and extreme climate hazards have led to shocks in the marine fishery industry. The resulting instability of the industry directly affects the market supply of and demand for seafood. We conduct a case study of a marine fishery industry in Taiwan that incorporates social concern assessments of risk perception and judgements of risk acceptance through risk management processes. Furthermore, we incorporate stakeholder participatory processes to reduce the gap in awareness of adaptation and to increase the opportunity to reach consensus and develop an integrated risk management model that enables decision-makers to better meet the needs of society. These measures will enhance all parties’ willingness to adapt and help achieve the goal of public–private collaboration in facing climate change challenges. Full article

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

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19 pages, 7312 KiB

Open AccessArticle

Transcriptome Sequencing Analysis Reveals Dynamic Changes in Major Biological Functions during the Early Development of Clearhead Icefish, Protosalanx chinensis

by Xuemei Tang, Shulun Jiang, Henglin Wang, Yanfeng Zhou, Fei Peng, Xizhao Zhang, Yifan Zhou, Shiyue Guo and Yang You

Fishes 2022, 7(3), 115; https://doi.org/10.3390/fishes7030115 - 21 May 2022

Cited by 3 | Viewed by 2530

Abstract

Early development, when many important developmental events occur, is a critical period for fish. However, research on the early development of clearhead icefish is very limited, especially in molecular research. In this study, we aimed to explore the dynamic changes in the biological [...] Read more.

Early development, when many important developmental events occur, is a critical period for fish. However, research on the early development of clearhead icefish is very limited, especially in molecular research. In this study, we aimed to explore the dynamic changes in the biological functions of five key periods in clearhead icefish early development, namely the YL (embryonic), PM (first day after hatching), KK (fourth day after hatching), LC (seventh day after hatching), and SL (tenth day after hatching) stages, through transcriptome sequencing and different analysis strategies. A trend expression analysis and an enrichment analysis revealed that the expression ofgenes encoding G protein-coupled receptors and their ligands, i.e., prss1_2_3, pomc, npy, npb, sst, rln3, crh, gh, and prl that are associated with digestion and feeding regulation gradually increased during early development. In addition, a weighted gene co-expression network analysis (WGCNA) showed that eleven modules were significantly associated with early development, among which nine modules were significantly positively correlated. Through the enrichment analysis and hub gene identification results of these nine modules, it was found that the pathways related to eye, bone, and heart development were significantly enriched in the YL stage, and the ccnd2, seh1l, kdm6a, arf4, and ankrd28 genes that are associated with cell proliferation and differentiation played important roles in these developmental processes; the pak3, dlx3, dgat2, and tas1r1 genes that are associated with jaw and tooth development, TG (triacylglycerol) synthesis, and umami amino acid receptors were identified as hub genes for the PM stage; the pathways associated with aerobic metabolism and unsaturated fatty acid synthesis were significantly enriched in the KK stage, with the foxk, slc13a2_3_5, ndufa5, and lsc2 genes playing important roles; the pathways related to visual perception were significantly enriched in the LC stage; and the bile acid biosynthetic and serine-type peptidase activity pathways were significantly enriched in the SL stage. These results provide a more detailed understanding of the processes of early development of clearhead icefish. Full article

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27 pages, 3651 KiB

Open AccessArticle

The Fishery Value Chain Analysis in Taiwan

by Tsung-Yu Yang, Hsing-Chun Lin and Wen-Hong Liu

Fishes 2022, 7(3), 114; https://doi.org/10.3390/fishes7030114 - 16 May 2022

Cited by 1 | Viewed by 3697

Abstract

Although the GDP of the fishery sector accounts for less than 0.3% of Taiwan’s GDP, there are many secondary and tertiary industries related to fisheries that add great value to the country’s economy. Therefore, when analyzing and calculating the output value and value [...] Read more.

Although the GDP of the fishery sector accounts for less than 0.3% of Taiwan’s GDP, there are many secondary and tertiary industries related to fisheries that add great value to the country’s economy. Therefore, when analyzing and calculating the output value and value added of the fishery sector, the relevance of these upstream and downstream industries should be considered jointly, and the value chain of the fishery industry should be studied and analyzed in order to truly present the value added created by fishery. This study aims to do this by first analyzing not only the primary fishery industry, but the value chain of the fishery industry at different stages such as fishery production, marine fishing, aquaculture, fishery processing, retail and services, and supportive systems. Then the value added of the whole fishery value chain to Taiwan’s GDP is estimated by using the Leontief input–output model, from the perspective of industry linkages and covering the period from 2011 to 2018. The empirical results suggest that the value added created by fishery and related industries accounted for 2.96% of the GDP in 2011, which rose to 3.11% in 2014, fell to 2.87% in 2015, rose to 2.93% in 2017, and fell to 2.84% in 2018. From 2011 to 2018, the amount of value added created by fisheries and related industries rose from NT$ 422.8 billion to NT$ 520.9 billion. The primary fishery sector has the largest contribution, followed by the fishery input sector, and transportation and sale service sector, and the fishery product processing sector has the lowest contribution rate. The empirical results provide important implications and references to the policy makers. Full article

(This article belongs to the Special Issue Synergistic Effects of Hydroclimate and Fisheries)

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20 pages, 3605 KiB

Open AccessEditor’s ChoiceArticle

Utilization of Fishery-Processing By-Product Squid Pens for Scale-Up Production of Phenazines via Microbial Conversion and Its Novel Potential Antinematode Effect

by Thi Hanh Nguyen, San-Lang Wang, Thi Huyen Nguyen, Manh Dung Doan, Thi Ha Trang Tran, Van Anh Ngo, Nhat Duoc Ho, Thi Ngoc Tran, Chien Thang Doan, Van Chung Do, Anh Dzung Nguyen and Van Bon Nguyen

Fishes 2022, 7(3), 113; https://doi.org/10.3390/fishes7030113 - 15 May 2022

Cited by 6 | Viewed by 2855

Abstract

Fishery by-products (FBPs) have been increasingly investigated for the extraction and production of a vast array of active molecules. The aim of this study was to produce phenazine compounds from FBPs via microbial fermentation and assess their novel antinematode effect. Among various FBPs, [...] Read more.

Fishery by-products (FBPs) have been increasingly investigated for the extraction and production of a vast array of active molecules. The aim of this study was to produce phenazine compounds from FBPs via microbial fermentation and assess their novel antinematode effect. Among various FBPs, squid pen powder (SPP) was discovered as the most suitable substrate for phenazine production by Pseudomonas aeruginosa TUN03 fermentation. Various small-scale experiments conducted in flasks for phenazine production indicated that the most suitable was the newly designed liquid medium which included 1% SPP, 0.05% MgSO₄, and 0.1% Ca₃(PO₄)₂ (initial pH 7). Phenazines were further studied for scale-up bioproduction in a 14 L bioreactor system resulting in a high yield (22.73 µg/mL) in a much shorter cultivation time (12 h). In the fermented culture broth, hemi-pyocyanin (HPC) was detected as a major phenazine compound with an area percentage of 11.28% in the crude sample. In the bioactivity tests, crude phenazines and HPC demonstrate novel potential nematicidal activity against black pepper nematodes, inhibiting both juveniles (J2) nematodes and egg hatching. The results of this work suggest a novel use of SPP for cost-effective bioproduction of HPC, a novel potential nematodes inhibitor. Moreover, the combination of MgSO₄ and Ca₃(PO₄)₂ was also found to be a novel salt composition that significantly enhanced phenazine yield by P. aeruginosa fermentation in this work. Full article

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13 pages, 5179 KiB

Open AccessFeature PaperArticle

Inter-Otolith Differences in Strontium Markings: A Case Study on the Juvenile Crucian Carp Carassius carassius (Linnaeus, 1758)

by Yahua Zhu, Tao Jiang, Xiubao Chen, Hongbo Liu, Quinton Phelps and Jian Yang

Fishes 2022, 7(3), 112; https://doi.org/10.3390/fishes7030112 - 15 May 2022

Cited by 3 | Viewed by 3204

Abstract

The release of hatchery-reared fish fry for restocking is important for the enrichment of fishery resources; however, the effective evaluation of the success rate of marking such fish is challenging. We exposed juvenile crucian carp (Carassius carassius) to a single concentration [...] Read more.

The release of hatchery-reared fish fry for restocking is important for the enrichment of fishery resources; however, the effective evaluation of the success rate of marking such fish is challenging. We exposed juvenile crucian carp (Carassius carassius) to a single concentration of SrCl₂·6H₂O for 5 d and evaluated the efficiency of Sr marking of the fish otoliths (sagittae, asterisci, and lapilli) using an electron probe micro-analyzer. Sr marking signatures formed a peak in all otolith types, with a marking success rate of 100%. The ratio of Sr to Ca in the lapilli and sagittae was higher than that in the asterisci. It took 2 d from the beginning of immersion to the deposition of Sr on the lapilli and sagittae, and the time delay for asterisci was 1 d. For the lapilli and sagittae, it took 16 d to terminate Sr marking and fully recover to the pre-marking Sr level, whereas it was 12 d for the asterisci. The application of the Sr dose had no effect on the survival or growth of the carp. This study demonstrated that the lapilli are the most suitable otolith type for Sr marking observations in crucian carp and provides a theoretical basis and technical support for carp restocking using the Sr marking approach. Full article

(This article belongs to the Special Issue Otoliths and Their Applications in Fishery Science)

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