Fishes

12 pages, 1531 KiB

Open AccessArticle

Use of Environmental DNA to Evaluate the Spatial Distribution of False Kelpfish (Sebastiscus marmoratus) in Nearshore Areas of Gouqi Island

by Rijin Jiang, Huibo Hao, Rui Yin, Peng Zhao, Feng Chen, Yongdong Zhou and Xuejun Chai

Fishes 2024, 9(10), 418; https://doi.org/10.3390/fishes9100418 (registering DOI) - 19 Oct 2024

Abstract

This study aims to explore the spatial distribution of false kelpfish (Sebastiscus marmoratus) in the mussel farming area, artificial reef areas of Gouqi Island (Shengsi, China), and natural areas using eDNA detection methods. Surface and bottom water samples were collected at [...] Read more.

This study aims to explore the spatial distribution of false kelpfish (Sebastiscus marmoratus) in the mussel farming area, artificial reef areas of Gouqi Island (Shengsi, China), and natural areas using eDNA detection methods. Surface and bottom water samples were collected at 12 stations in November 2022 and April 2023, totaling 52 samples. We used species-specific primers and probes for quantitative PCR (qPCR) detection of Sebastiscus marmoratus eDNA. The eDNA concentrations differed seasonally (p < 0.05) and did not differ (p > 0.05) among the three sampling areas and two water layers. The greatest eDNA concentrations occurred in the surface layer during the spring. Higher concentrations of Sebastiscus marmoratus eDNA were also found in the mussel aquaculture area. Temperature exhibited a significant positive correlation with Sebastiscus marmoratus eDNA concentration (p < 0.05). Additionally, we developed linear equations predicting the relationship between environmental factors and environmental factors, providing a reference for future fishery resource surveys. Full article

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

► Show Figures

Figure 1

16 pages, 2709 KiB

Open AccessArticle

Growth, Productivity and Nutrient Uptake Rates of Ulva lactuca and Devaleraea mollis Co-Cultured with Atractoscion nobilis in a Land-Based Seawater Flow-Through Cascade IMTA System

by Yuanzi Huo, Matthew S. Elliott and Mark Drawbridge

Fishes 2024, 9(10), 417; https://doi.org/10.3390/fishes9100417 (registering DOI) - 19 Oct 2024

Viewed by 198

Abstract

To advance environmentally friendly technologies in the aquaculture of Atractoscion nobilis, and simultaneously to diversify seafood production, a 79-day trial was conducted to assess the performance of Ulva lactuca and Devaleraea mollis cultured in the effluent from A. nobilis in a land-based [...] Read more.

To advance environmentally friendly technologies in the aquaculture of Atractoscion nobilis, and simultaneously to diversify seafood production, a 79-day trial was conducted to assess the performance of Ulva lactuca and Devaleraea mollis cultured in the effluent from A. nobilis in a land-based integrated multi-trophic aquaculture (IMTA) system in southern California, USA. Water quality and performance of macroalgae were measured weekly. The impacted factors on the growth of macroalgae and nutrient uptake rate of macroalgae were assessed. The specific growth rate of juvenile A. nobilis was 0.47–0.52%/d. Total ammonia nitrogen in effluents of A. nobilis tanks ranged from 0.03 to 0.19 mg/L. Ulva lactuca and D. mollis achieved an average productivity of 24.53 and 14.40 g dry weight (DW)/m²/d. The average nitrogen content was 3.48 and 4.89% DW, and accordingly, the average nitrogen uptake rate was 0.88 and 0.71 g/m²/d, respectively. Temperature and nutrient concentration were key factors impacting macroalgae growth, and light intensity also impacted the growth of D. mollis. The high protein content of U. lactuca and D. mollis would make them good for use as human or animal food, or for use in other industries. Research on the interaction effects between seawater exchange rates and aeration rates on the performance and nutrient uptake rates of macroalgae will be conducted in future studies. Full article

(This article belongs to the Special Issue Advances in Integrated Multi-Trophic Aquaculture)

► Show Figures

Figure 1

15 pages, 4480 KiB

Open AccessArticle

Comparing the Efficacy of Seaweed Rafts and Light Traps in Monitoring the Variation in Abundance and Diversity of Juvenile Fish Assemblage During Diurnal and Nocturnal Periods in Tropical Coastal Waters

by Chufeng Fan, Zhongbo Miao, Yongxiang Li, Wentong Xia, Ying Lu, Songguang Xie and Yiqing Song

Fishes 2024, 9(10), 416; https://doi.org/10.3390/fishes9100416 - 17 Oct 2024

Viewed by 160

Abstract

This study evaluates the relative and combined effectiveness of seaweed rafts and light traps in attracting juvenile fish, focusing on diel variations in juvenile fish assemblage in the tropical coastal waters of Gaolong Bay, Wenchang City, Hainan Province. Sampling was conducted in May [...] Read more.

This study evaluates the relative and combined effectiveness of seaweed rafts and light traps in attracting juvenile fish, focusing on diel variations in juvenile fish assemblage in the tropical coastal waters of Gaolong Bay, Wenchang City, Hainan Province. Sampling was conducted in May 2023 during various time periods using self-made artificial drifting seaweed rafts and light traps. The nonparametric Kruskal–Wallis was employed to compare the diversity and catch per unit effort of juvenile fish across different time periods and sampling methods. The Permutational Multivariate Analysis of Variance, heatmaps, and Principal Coordinates Analysis were used to analyze and visualize the differences between juvenile fish assemblages. Our findings indicate that light traps were particularly effective during nocturnal periods, capturing a diverse array of species and achieving the highest richness and evenness indices. Seaweed rafts demonstrated the lowest diversity indices, largely due to the dominance of specific species, which likely contributed to the competitive exclusion of other species. Seaweed rafts showed significant effectiveness during noon, providing critical habitat and shelter that attracted juvenile fish despite the lower diversity. While each method demonstrated specific advantages, their combined approach did not significantly improve juvenile fish aggregation compared to the individual method. These findings underscore the importance of considering diel and tidal cycles in the selection of sampling methods, as aligning the method with the time of day can greatly enhance the accuracy of biodiversity assessments, leading to more informed conservation and management strategies for tropical coastal waters. Full article

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

► Show Figures

Figure 1

14 pages, 2341 KiB

Open AccessArticle

Tissue-Specific Toxicity in Common Carp (Cyprinus carpio) Caused by Combined Exposure to Triphenyltin and Norfloxacin

by Yiwei Liu, Luoxin Li, Siqi Zhang, Minghao Yin, Tengzhou Li, Bianhao Zeng, Ling Liu, Ping Li and Zhihua Li

Fishes 2024, 9(10), 415; https://doi.org/10.3390/fishes9100415 - 17 Oct 2024

Viewed by 196

Abstract

Triphenyltin (TPT) is a commonly encountered organotin compound known for its endocrine-disrupting properties; it frequently interacts with antibiotics in aquatic environments. In this study, common carp (Cyprinus carpio) (17.43 ± 4.34 g, 11.84 ± 0.88 cm) were chosen as the experimental organisms. According [...] Read more.

Triphenyltin (TPT) is a commonly encountered organotin compound known for its endocrine-disrupting properties; it frequently interacts with antibiotics in aquatic environments. In this study, common carp (Cyprinus carpio) (17.43 ± 4.34 g, 11.84 ± 0.88 cm) were chosen as the experimental organisms. According to the environmental concentration in the heavily polluted area, the control group and the experimental groups were exposed for 21 days to the following treatments: 1 μg/L TPT, 1 mg/L NOR, and a combination of 1 μg/L TPT plus 1 mg/L NOR. The investigation examined the individual and combined toxicities of TPT and norfloxacin (NOR) on the gill, liver, and gut tissues of common carp in highly polluted areas. The findings revealed tissue-specific variations in 1L-1β enzyme activity; specifically, 1L-1β enzyme activity exhibited a significant reduction in liver tissue under both NOR exposure and combined exposure, indicating that high concentrations of NOR had the most pronounced impact on the immune system of liver tissue. Furthermore, the gene expression levels of IL-1β, Lysozyme-C, NKA, and CPT1 in the liver, intestinal, and gill tissues showed differences after exposure. In addition, TPT exerted the most significant effect on intestinal tissue, followed by the liver and gill tissues. Interestingly, when TPT and NOR were exposed together, the toxic effects on all tissues were reduced, suggesting the existence of antagonistic effects. Full article

► Show Figures

Figure 1

13 pages, 2935 KiB

Open AccessArticle

Technical Efficiency of the Nile Perch Fishing Fleet on Lake Victoria: A Comparative Perspective on the Three Riparian Countries Kenya, Tanzania and Uganda

by Veronica Mpomwenda, Tumi Tómasson, Jón Geir Pétursson, Anthony Taabu-Munyaho, Chrispine Sangara Nyamweya and Daði Mar Kristófersson

Fishes 2024, 9(10), 414; https://doi.org/10.3390/fishes9100414 - 17 Oct 2024

Viewed by 233

Abstract

Lake Victoria, which is shared by Kenya, Tanzania, and Uganda, faces escalating concerns over sustainable fisheries amidst expanding fishing efforts. This study aims to investigate how technical efficiency (TE) and labor productivity (LP) of the Nile perch fishing fleet vary across the three [...] Read more.

Lake Victoria, which is shared by Kenya, Tanzania, and Uganda, faces escalating concerns over sustainable fisheries amidst expanding fishing efforts. This study aims to investigate how technical efficiency (TE) and labor productivity (LP) of the Nile perch fishing fleet vary across the three riparian countries. Using a nine-year dataset spanning from 2005 to 2021 and employing Stochastic Frontier Analysis, this study evaluates the TE of the fleet, where LP is determined as catch per crew hour fished in a day for three vessel types: motorized, paddled, and sailed. Motorized fleets had the highest mean technical efficiency (0.60–0.66), compared to paddled (0.29–0.49), and sailed vessel categories (0.24–0.46). Sailed vessels declined in all countries owing to their low TE. In Kenya, TE and LP increased for paddled vessels, especially in the period from 2015 to 2021, and a slight increase was also indicated for motorized vessels. Conversely, Uganda and Tanzania experienced gradual declines in TE and LP, particularly from 2015 to 2021, a period of rigorous law enforcement that led to declines in the number of paddled vessels by 50% and 7%, respectively, and a contrasting increase in motorized vessels. By 2021, the number of Ugandan motorized vessels had increased greatly but TE had declined compared to Kenya and Tanzania, a sign of overcapacity. The findings underscore the need for region-specific policies that address economic differences, policy implementation impacts, and resource health to promote sustainable transboundary fisheries management on Lake Victoria. Full article

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

► Show Figures

Figure 1

13 pages, 1260 KiB

Open AccessArticle

Analysis of the Polyculture Model of the Bivalves Anadara broughtonii and Chlamys farreri in Suspension Cages in Shallow Seas

by Chunnuan Zhao, Liqun Ren, Shuai Xu, Yuping Wu, Haiying Han, Bo Li, Yanxin Zheng, Yang Chen, Xiwen Wang, Nini Fan, Junjie Li, Chaoyi Xie, Shuai Cai and Tao Yu

Fishes 2024, 9(10), 413; https://doi.org/10.3390/fishes9100413 - 17 Oct 2024

Viewed by 205

Abstract

This study examined the survival rates of Anadara broughtonii and Chlamys farreri with varying heights throughout winter and summer aquaculture periods under varying ratios of mixed-culture conditions in marine environments. The aim was to assess the viability and economic advantages of mixed-culture practices [...] Read more.

This study examined the survival rates of Anadara broughtonii and Chlamys farreri with varying heights throughout winter and summer aquaculture periods under varying ratios of mixed-culture conditions in marine environments. The aim was to assess the viability and economic advantages of mixed-culture practices among different bivalve species. Results indicate that the winter (from December to February of the following year) mortality rate for A. broughtonii in mixed culture ranges from 12.04% to 16.85%, markedly lower than in single-species cultures. Mixed-culture A. broughtonii measuring 2.5–4.0 cm exhibit a significantly reduced summer (from July to September) mortality rate compared to those in single-species cultures (p < 0.05). No significant mortality difference was observed between the monoculture and polyculture of C. farreri. Growth rates of C. farreri and A. broughtonii showed no significant differences between monoculture and polyculture conditions. The optimal size for combining two different species of bivalves is 2.5 cm, with a 1:1 ratio being the most effective. An equal number of seedlings were cultivated across various seawater aquaculture systems for a period of one year. The survival rates of monoculture seedlings of Anadara broughtonii and Chlamys farreri were 60.34% and 86.55%, respectively. In contrast, polyculture seedlings exhibited higher survival rates after one year of mariculture, with Anadara broughtonii at 73.36% and Chlamys farreri at 89.74%. The polyculture of A. broughtonii and C. farreri in suspension cages demonstrates a favorable input–output ratio of 1:2.02. This approach effectively reduces winter and summer mortality rates of A. broughtonii, representing an efficient new method for marine bivalve aquaculture. Full article

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

► Show Figures

Figure 1

12 pages, 2514 KiB

Open AccessArticle

Seasonal Distribution of Key Small-Sized Fish in the South Inshore of Zhejiang, China

by Minghao Xu, Xiaodi Gao, Weicheng Liu and Jiaqi Wang

Fishes 2024, 9(10), 412; https://doi.org/10.3390/fishes9100412 - 13 Oct 2024

Viewed by 358

Abstract

Small-sized fish are a vital food source for large predatory commercial fish and play a key role in marine food webs, bridging lower and higher trophic levels. They are indispensable in maintaining the energy flow and material cycling within aquatic ecosystems. This study [...] Read more.

Small-sized fish are a vital food source for large predatory commercial fish and play a key role in marine food webs, bridging lower and higher trophic levels. They are indispensable in maintaining the energy flow and material cycling within aquatic ecosystems. This study utilized bottom-trawl survey data from 2017 to 2020 along the south inshore of Zhejiang, China, complemented by concurrent environmental data, to examine the influence of environmental factors on the resource density and seasonal distribution patterns of four dominant small-sized fish species. The research findings indicated that SSH (sea surface height) and Chl (chlorophyll-a concentration) emerged as the key environmental factors influencing resource densities, with all four species exhibiting similar preferences toward these variables. However, significant disparities were observed in their preferences for SST (sea surface temperature), SSS (sea surface salinity), and DO (dissolved oxygen). The various species’ resource density and distribution patterns underwent significant seasonal variations. Additionally, the seasons and regions with the highest resource densities consistently aligned, occurring predominantly in autumn within the northern waters of the study area. This research further elucidated the environmental predilections and seasonal spatial distribution traits of small-sized fish in the south inshore of Zhejiang, an important feeding ground for economic fish species in the East China Sea. This provides scientific backing for forecasting alterations in coastal fishery resources under environmental and climate change scenarios and supports ecosystem-based fisheries management strategies. Full article

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

► Show Figures

Figure 1

19 pages, 5614 KiB

Open AccessArticle

Comparative Transcriptomic Profiling of Brain and Liver in Phoenix Barbs (Spinibarbus denticulatus denticulatus) with Differential Growth Rates

by Xi Xie, Jiamiao Zhuang, Xianping Liao, Zhengsheng Xu, Wenlang Liang, Yilin Su, Li Lin, Jungang Xie and Weiqiang Lin

Fishes 2024, 9(10), 411; https://doi.org/10.3390/fishes9100411 (registering DOI) - 13 Oct 2024

Viewed by 294

Abstract

Phoenix barb (Spinibarbus denticulatus denticulatus) is a notable fish species in South China and is valued for its ecological and economic importance. To elucidate the molecular basis underlying its growth, we collected transcriptome profiles from the brains and livers of individual [...] Read more.

Phoenix barb (Spinibarbus denticulatus denticulatus) is a notable fish species in South China and is valued for its ecological and economic importance. To elucidate the molecular basis underlying its growth, we collected transcriptome profiles from the brains and livers of individual fish with different growth rates and compared differentially expressed genes (DEGs) at 3 and 9 months after hatching (MAH). Kyoto Encyclopedia of Genes and Genomes (KEGG) analysis revealed that the pathways associated with growth were predominantly enriched in fatty acid biosynthesis, AMPK signaling, PI3K-Akt signaling, estrogen signaling, and protein metabolism. Notably, a greater number of DEGs from the fast-growing group were associated with these pathways at the early growth stage (3 MAH) than at the later stage (9 MAH). Real-time quantitative PCR results further validated that the genes involved in these pathways exhibited higher expression levels in fast-growing samples. This study enhances our understanding of the genetic mechanisms underlying growth rate differences and provides valuable genetic resources for future growth-related molecular breeding programs of phoenix barbs. Full article

(This article belongs to the Section Genetics and Biotechnology)

► Show Figures

Figure 1

12 pages, 1200 KiB

Open AccessArticle

Effect of a Commercial Polyphenol Compound on the Performance and Antioxidant Status of Penaeus vannamei

by Hallypher Deyrrikson Ferreira Colares, Cecília de Souza Valente, Izabel Volkweis Zadinelo, Caio Henrique do Nascimento Ferreira, Milena Cia Retcheski, Luisa Helena Cazarolli, Lodewijk Rosseel and Eduardo Luis Cupertino Ballester

Fishes 2024, 9(10), 410; https://doi.org/10.3390/fishes9100410 - 12 Oct 2024

Viewed by 253

Abstract

The study evaluated the effect of a commercial polyphenol (ELIFE^®) on the growth performance and antioxidant defense system of Penaeus vannamei juveniles. The study was completely randomized with three experimental groups and eight repetitions, divided into two 28-day phases. The experimental [...] Read more.

The study evaluated the effect of a commercial polyphenol (ELIFE^®) on the growth performance and antioxidant defense system of Penaeus vannamei juveniles. The study was completely randomized with three experimental groups and eight repetitions, divided into two 28-day phases. The experimental groups consisted of different dietary inclusion levels of ELIFE^® (0.0, 0.5, and 1.0 g kg⁻¹). Five shrimps were stocked in each experimental unit. Growth performance, oxidative stress, and enzymatic activity in shrimp hepatopancreas were assessed. In Phase 1, shrimp fed ELIFE^®, regardless of inclusion level, displayed higher specific growth rate, final weight, and final length than the control group. In Phase 2, shrimp fed 1.0 g kg⁻¹ ELIFE^® showed higher final biomass and SGR than all other experimental groups; they also displayed increased reduced glutathione and glutathione-S-transferase activities. In both test phases, shrimp fed 1.0 g kg⁻¹ ELIFE^® presented increased glutathione reductase activity compared to all other experimental groups. In both test phases, shrimp fed ELIFE^®, regardless of inclusion level, exhibited increased glutathione peroxidase activity compared to control groups. Thus, ELIFE^® enhanced the antioxidant defense system of P. vannamei and led to better shrimp performance and survival. This study recommends dietary supplementation with 1.0 g kg⁻¹ ELIFE^® for P. vannamei juveniles. Full article

(This article belongs to the Special Issue Advances in Shrimp Aquaculture: Management and Sustainability)

► Show Figures

Figure 1

13 pages, 2737 KiB

Open AccessArticle

The Structure Analysis and mRNA Expression of CaV2 Gene Responding to Hypoxia Stress in Anadara granosa

by Yang Zhang, Hongxing Liu, Yongbo Bao and Zhilan Peng

Fishes 2024, 9(10), 409; https://doi.org/10.3390/fishes9100409 - 12 Oct 2024

Viewed by 269

Abstract

The blood clam (Anadara granosa) is an economic bivalve that is relatively tolerant to hypoxia, but its molecular mechanism of hypoxia tolerance is unclear. We found that a significant decrease in extracellular Ca²⁺ concentration and a marked increase in intracellular [...] Read more.

The blood clam (Anadara granosa) is an economic bivalve that is relatively tolerant to hypoxia, but its molecular mechanism of hypoxia tolerance is unclear. We found that a significant decrease in extracellular Ca²⁺ concentration and a marked increase in intracellular Ca²⁺ concentration was observed in the blood clam through the fluorescence probe method, under hypoxic conditions at 0.5 mg/L. Concomitantly, there was a downward trend in the expression level of CaV2 mRNA, whereas NFAT (nuclear factor of activated T cells) expression increased by qRT-PCR. These findings suggest that the elevated intracellular Ca²⁺ concentration may activate negative transcription factors of NFAT, which subsequently suppresses the transcription of CaV2, leading to its decreased expression. Then, the NFAT RNA interference experiments supported this hypothesis. Sequence analysis and 3D structure prediction revealed conserved and mutated residue sites in blood clam compared to other bivalves. Hypoxia-induced changes in intracellular and extracellular Ca²⁺ concentrations, activating transcription factor NFAT and suppressing CaV2 expression. This study highlights the key roles of CaV2 and NFAT in hypoxia adaptation, paving the way for further exploration of hypoxia tolerance mechanisms in mollusca. Full article

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

► Show Figures

Graphical abstract

15 pages, 3046 KiB

Open AccessFeature PaperArticle

The Personality Traits and Interactive Behavior of Chinese Mitten Crab (Eriocheir sinensis)

by Jianyang Sun, Dongxin Zhang, Yuhang Hong, Chengyi Weng, Yangyang Pang, Yongxu Cheng and Xiaozhen Yang

Fishes 2024, 9(10), 408; https://doi.org/10.3390/fishes9100408 - 12 Oct 2024

Viewed by 231

Abstract

Agonistic behavior is a common behavior among agonistic Chinese mitten crabs (Eriocheir sinensis). Such behavior often leads to limb loss or physical impairment, and significantly affects the survival, growth, and quality of the crabs, and even the yield and economic value [...] Read more.

Agonistic behavior is a common behavior among agonistic Chinese mitten crabs (Eriocheir sinensis). Such behavior often leads to limb loss or physical impairment, and significantly affects the survival, growth, and quality of the crabs, and even the yield and economic value for E. sinensis. Agonistic behavior often occurs in agonistic crabs, which is closely related to personality traits and interactive behavior of animals. E. sinensis has personality traits such as boldness, aggression, and exploration as evidenced by the partition-crossing experiment, mirror experiment, and shelter experiment. Agonistic crabs were identified as individuals with boldness, high aggression, and high exploration. The interactive behavior spectrum of E. sinensis was first obtained, consisting of 15 behaviors. This spectrum described and summarized all interactive behaviors of E. sinensis during fights. The interactive behavior characteristics of agonistic crabs were identified as darting, intimidating, grabbing, pushing, stretching, and visitation. These results lay a theoretical basis for in-depth behavioral research on E. sinensis in the future. The technique of identifying agonistic crabs by personality traits and interactive behaviors not only allows for the elimination of agonistic crabs from the aquaculture process and the reduction in negative impacts caused by aggressive crabs, but also allows for the breeding of non-agonistic crabs and the further reduction in the economic losses caused by fighting behaviors. Full article

► Show Figures

Figure 1

8 pages, 1113 KiB

Open AccessArticle

Influences of Cr(VI) on SOD Activity, MDA, and MT Content in the Hepatopancreas and Gill of Portunus trituberculatus

by Lei Li, Chenshan Shao, Guodong Xv, Linlan Lv, Jiacheng Jiang, Weiyi Zou, Weiwei Su, Yanming Sui and Mei Jiang

Fishes 2024, 9(10), 407; https://doi.org/10.3390/fishes9100407 - 11 Oct 2024

Viewed by 347

Abstract

The toxic effect and differences of Cr(VI) on superoxide dismutase (SOD) activity, MDA, and metallothionein (MT) content in the hepatopancreas and gill of Portunus trituberculatus were investigated during Cr(VI) enrichment (15 days) and release experiments (15 days). Results showed that the 1.50 and [...] Read more.

The toxic effect and differences of Cr(VI) on superoxide dismutase (SOD) activity, MDA, and metallothionein (MT) content in the hepatopancreas and gill of Portunus trituberculatus were investigated during Cr(VI) enrichment (15 days) and release experiments (15 days). Results showed that the 1.50 and 0.30 mg/L test groups significantly exhibited higher SOD, MDA, and MT content in the hepatopancreas and gill compared with the control group after 15 days of enrichment (p < 0.05). After 15 days of Cr release, the SOD, MDA, and MT content in the hepatopancreas and gill of both test groups recovered to the normal level of the control group (p > 0.05). The gill of P. trituberculatus achieved the highest SOD activity, MDA, and MT content earlier than the hepatopancreas, but the highest values were lower. The gill showed a shorter recovery time than the hepatopancreas. We concluded that the gill of P. trituberculatus exhibited a more rapid response to, and recovery from, Cr(VI) exposure compared to the hepatopancreas, making it a more sensitive tissue for assessing Cr(VI) toxicity, though both tissues showed a capacity for recovery after the removal of the contaminant. Full article

(This article belongs to the Special Issue Risk Assessment of Pollutant Residues in Aquatic Products and Aquaculture Environments)

► Show Figures

Figure 1

15 pages, 12189 KiB

Open AccessArticle

Lactococcus garvieae as a Novel Pathogen in Cultured Pufferfish (Takifugu obscurus) in China

by Ruilong Xu, Zhongning He, Yiyang Deng, Yihao Cen, Zequan Mo, Xueming Dan and Yanwei Li

Fishes 2024, 9(10), 406; https://doi.org/10.3390/fishes9100406 - 10 Oct 2024

Viewed by 408

Abstract

In October 2023, a disease outbreak in pufferfish (Takifugu obscurus) farms in Zhongshan City, Guangdong, China, caused high mortality. Diseased fish (mean length: 15 ± 1 cm) exhibited swimming disorders, fin rot, hemorrhage, and an enlarged spleen. Histopathological observations generally revealed [...] Read more.

In October 2023, a disease outbreak in pufferfish (Takifugu obscurus) farms in Zhongshan City, Guangdong, China, caused high mortality. Diseased fish (mean length: 15 ± 1 cm) exhibited swimming disorders, fin rot, hemorrhage, and an enlarged spleen. Histopathological observations generally revealed inflammation, necrosis, and congestion in the spleen, kidneys, and brain tissues. The most severe pathological changes included interstitial edema and tubular atrophy in the kidneys, hemosiderin deposition in the spleen, massive red blood cell infiltration, and a decrease in lymphocytes. A single strain of bacteria (Tol-1) was isolated from the diseased pufferfish and identified as a Gram-positive streptococcus strain, exhibiting α-hemolysis on sheep blood agar plates. Through biochemical characterization, 16S rDNA sequencing, morphological analysis, and specific primer-based identification, the Tol-1 strain was identified as Lactococcus garvieae, serotype I. Antimicrobial susceptibility testing indicated that Tol-1 was sensitive to Chloramphenicol, Ampicillin, Cephalexin, and Doxycycline, but resistant to Kanamycin, Gentamicin and Ciprofloxacin. In addition, 15 common virulence factors were detected in the Tol-1 strain, including adhPav, adhPsaA, adhC I–II, adh, and hly 1–3. Pufferfish (mean length: 17 ± 1 cm) subjected to artificial infection via intraperitoneal injection (IP) with the Tol-1 strain exhibited clinical symptoms and histopathological damage similar to those observed in naturally infected fish. An infection dose of 1 × 10⁵ CFU/fish resulted in 80% mortality. The study fulfilled Koch’s postulates, indicating that the disease outbreak in pufferfish was caused by L. garvieae, which exhibited a high mortality rate in pufferfish despite the subtle clinical symptoms. These results serve as a warning for pufferfish farming areas and provide a scientific basis for future prevention and control efforts. Full article

(This article belongs to the Special Issue Fish Immunological Mechanism and Control of Pathogens)

► Show Figures

Figure 1

18 pages, 2459 KiB

Open AccessArticle

Effects of Taurine and Enzymatic Cottonseed Protein Concentrate Supplementation in Low-Fishmeal Diet on Growth, Liver Antioxidant Capacity, and Intestinal Health of Golden Pompano (Trachinotus ovatus)

by Zhanzhan Wang, Shuling Liao, Zhong Huang, Jun Wang, Yun Wang, Wei Yu, Heizhao Lin, Zhenhua Ma, Zhenyan Cheng and Chuanpeng Zhou

Fishes 2024, 9(10), 405; https://doi.org/10.3390/fishes9100405 - 9 Oct 2024

Viewed by 701

Abstract

This study was conducted to investigate the impacts of the dietary addition of taurine and enzymatic cottonseed protein concentrate (ECPC) in low-fishmeal diet on the growth performance, plasma biochemical indices, hepatic antioxidant capacity, intestinal anti-inflammatory capacity, intestinal microflora, and muscle quality of golden [...] Read more.

This study was conducted to investigate the impacts of the dietary addition of taurine and enzymatic cottonseed protein concentrate (ECPC) in low-fishmeal diet on the growth performance, plasma biochemical indices, hepatic antioxidant capacity, intestinal anti-inflammatory capacity, intestinal microflora, and muscle quality of golden pompano (Trachinotus ovatus). A total of three isonitrogenous diets were given to 225 golden pompanos (5.6 ± 0.14 g). They were randomly divided into nine cages (1.0 m × 1.0 m × 1.5 m; three cages per treatment) with equal stocking numbers of twenty-five fish per cage. The results indicated that the CSM-TC group significantly increased the growth performance of juvenile T. ovatus (p < 0.05). The results indicated that compared with other groups, the addition of 1% ECPC and 0.25% taurine has been found to enhance the WGR (weight gain rate), SGR (specific growth rate), and CF (condition factor). Compared with other groups, the relative expressions of GH, GHR1, GHR2, IGF1, IGF2, and MyoG were significantly higher in fish fed with CSM-TC. The results showed that CSM-TC significantly increased the activities of alkaline phosphatase, complement 3, and complement 4 enzymes (p < 0.05). The results showed that dietary CSM-TC increased the activities of hepatic superoxide dismutase and total antioxidant capacity enzymes. Compared with other groups, the hepatic relative expressions of Nrf2, HO-1, and GSH-Px were significantly higher in fish fed with CSM-TC. The results showed that dietary CSM-TC increased the activities of intestinal chymotrypsin, lipase, and α-amylase enzymes. A CSM-TC diet significantly increased the relative expressions of IL-10, ZO-1, Occludin, Claudin-3, and Claudin-15 (p < 0.05). The results showed that CSM-C significantly increased the index of Ace and Chao1 (p < 0.05). In conclusion, a high-fermented cottonseed meal diet can have detrimental effects on physiological health in golden pompano, while adding 1% ECPC and 0.25% taurine can improve hepatic and intestinal health via attenuating inflammation and oxidative stress. Full article

(This article belongs to the Section Nutrition and Feeding)

► Show Figures

Figure 1

23 pages, 8471 KiB

Open AccessArticle

Construction of a Growth Model and Screening of Growth-Related Genes for a Hybrid Puffer (Takifugu obscurus ♀ × Takifugu rubripes ♂)

by Chaoyu Wang, Yan Shi, Yuanye Gao, Shuo Shi, Mengmeng Wang, Yunlong Yao, Zhenlong Sun, Yaohui Wang and Zhe Zhao

Fishes 2024, 9(10), 404; https://doi.org/10.3390/fishes9100404 - 6 Oct 2024

Viewed by 735

Abstract

The obscure puffer (Takifugu obscurus) is a popular cultured species and accounts for around 50% of the total pufferfish production in China. A hybrid puffer was generated by crossing a female obscure puffer with a male tiger puffer (T. rubripes [...] Read more.

The obscure puffer (Takifugu obscurus) is a popular cultured species and accounts for around 50% of the total pufferfish production in China. A hybrid puffer was generated by crossing a female obscure puffer with a male tiger puffer (T. rubripes). Its growth model has not been developed and the genetic basis underlying its growth superiority has not yet been fully investigated. In this study, the growth model and morphological traits of the hybrid puffer were explored. The results indicated that the hybrid puffer exhibited a significant growth advantage compared to the obscure puffer. There were also significant differences in their morphological traits. We conducted genotyping-by-sequencing (GBS) on hybrid and obscure puffer groups, identifying 215,288 high-quality single nucleotide polymorphisms (SNPs) on 22 chromosomes. Subsequently, a total of 13 growth-related selection regions were identified via a combination of selection signatures and a genome-wide association study (GWAS); these regions were mainly located on chromosomes 10 and 22. Ultimately, the screened regions contained 13 growth-related genes, including itgav, ighv3-43, ighm, atp6v1b2, pld1, xmrk, inhba, dsp, dsg2, and dsc2, which regulate growth through a variety of pathways. Taken together, the growth models and candidate genes used in this study will aid our understanding of production characteristics and the genetic basis of growth rates. The hybrid will also be of great significance for the genome-assisted breeding of pufferfish in the future. Full article

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

► Show Figures

Figure 1

11 pages, 273 KiB

Open AccessArticle

The Impact of Thermal Treatments up to 140 °C on Amino Acid Digestibility of Fish Meal in Rainbow Trout (Oncorhynchus mykiss)

by Pedro Henrique Sessegolo Ferzola, Judith Ringel, Carsten Schulz and Martin Gierus

Fishes 2024, 9(10), 403; https://doi.org/10.3390/fishes9100403 - 6 Oct 2024

Viewed by 382

Abstract

Fish meal (FM) is an essential ingredient in fish feeds, but the thermal treatments used during its production might affect its nutrient availability. Therefore, an in vivo digestibility trial was conducted with three different thermal treated FM, at no heat treatment (control), 70, [...] Read more.

Fish meal (FM) is an essential ingredient in fish feeds, but the thermal treatments used during its production might affect its nutrient availability. Therefore, an in vivo digestibility trial was conducted with three different thermal treated FM, at no heat treatment (control), 70, and 140 °C. A total of 216 rainbow trout (230 ± 6.0 g) were randomly assigned to 12 tanks, and feces samples were collected by stripping. FM was produced by lyophilizing mackerel. The lyophilized FM (94% DM) was then divided into three groups: FM Control, which was not exposed to thermal treatments, and FM 70 °C and FM 140 °C, which were exposed for 1 h to the respective temperatures of its descriptions. A conventional FM-based (FM with 64% CP produced at 110 °C) control diet was used as a basal diet. In the experimental groups, 30% of the basal diet was replaced by one of the tested FMs. No differences in apparent total tract digestibility (ATTD) were observed between FM Control and 70 °C. Protein ATTD of FM 140 °C as well as Arg ATTD were lower compared to FM Control and 70 °C. The same effect was observed for His and Asp ATTD. The current study showed that thermal treatment affects FM macronutrient and amino acid ATTD. Full article

(This article belongs to the Section Nutrition and Feeding)

15 pages, 2982 KiB

Open AccessArticle

Otolith Microchemistry Reveals the Diversity of Migration Patterns and Spawning Ground Distribution of Coilia nasus from the Yangtze River Estuary

by Chao Song, Wenjie Yu, Ruohui Liu, Jilin Xie, Feipeng Li, Feng Zhao and Ping Zhuang

Fishes 2024, 9(10), 402; https://doi.org/10.3390/fishes9100402 - 6 Oct 2024

Viewed by 322

Abstract

Coilia nasus are an important fish resource in the Yangtze River, and the Yangtze River Estuary is a crucial migration pathway for them. In this study, we used otolith microchemistry to analyze the strontium/calcium (Sr/Ca) ratios and Sr contents in the sagitta otolith [...] Read more.

Coilia nasus are an important fish resource in the Yangtze River, and the Yangtze River Estuary is a crucial migration pathway for them. In this study, we used otolith microchemistry to analyze the strontium/calcium (Sr/Ca) ratios and Sr contents in the sagitta otolith of C. nasus from the south branch (SB) and north branch (NB) of the Yangtze River Estuary and obtained the diversity of migration patterns and spawning ground distribution for C. nasus. The results indicate that C. nasus from both branches include two types of habitat history: freshwater (F)–brackish water (B) (Type I) and F-B seawater (S) (Type II), with Type I being dominant at 62.50% in both branches. The C. nasus from the SB comprise six migration patterns, while that from the NB has seven migration patterns. The C. nasus from both branches hatch in F habitats. At the time of capture, the C. nasus from the SB predominantly remain in F, accounting for 62.5%, while C. nasus from the NB primarily stay in B, accounting for 87.5%. Throughout the migration process, C. nasus from both branches switch between different habitats, with C. nasus from the NB exhibiting more frequent transitions between F and B, showing a greater reliance on the estuarine brackish habitat. The radius of the first blue region near the core (L_f) and freshwater coefficient (Fc) of the otolith for C. nasus from both branches are divided into three groups: long-distance freshwater dependence (LD), medium-distance freshwater dependence (MD), and short-distance freshwater dependence (SD), with the LD only appearing in the SB, while the NB is primarily represented by MD. There is a correlation between the differences in L_f among different groups of C. nasus and the differences in the distance from the spawning grounds of C. nasus in different sections of the Yangtze River to the estuary (D_YRE), reflecting the distribution pattern of C. nasus spawning grounds in different sections of the Yangtze River. This study provides theoretical guidance for the protection of migration pathways and maintenance of spawning grounds for C. nasus, which have significant practical value in the precise management of C. nasus resources in the Yangtze River Estuary. Full article

► Show Figures

Figure 1

22 pages, 1699 KiB

Open AccessArticle

Exploring the Dual Benefits of Fermented and Non-Fermented Garlic Powder on Growth, Antioxidative Capacity, Immune Responses, and Histology in Gray Mullet (Liza ramada)

by Mohammed F. El Basuini, Mahasen M. E. A. Shaban, Abdelaziz M. El-Hais, Ali A. Soliman, Nermeen M. Abu-Elala, Islam I. Teiba, Mayada Alhoshy, Ghada R. Sallam, Ronick Spenly Shadrack, Kumbukani Mzengereza and Akram Ismael Shehata

Fishes 2024, 9(10), 401; https://doi.org/10.3390/fishes9100401 - 3 Oct 2024

Viewed by 464

Abstract

This study investigated the effects of dietary garlic powder and fermented garlic powder supplementation at 1% and 2% levels on growth performance, digestive tract efficacy, blood biochemistry, immunity, and antioxidant status of Liza ramada (n = 225 fish; 86.00 ± 0.42 g) over [...] Read more.

This study investigated the effects of dietary garlic powder and fermented garlic powder supplementation at 1% and 2% levels on growth performance, digestive tract efficacy, blood biochemistry, immunity, and antioxidant status of Liza ramada (n = 225 fish; 86.00 ± 0.42 g) over a 60-day period. Fish fed diets supplemented with both forms of garlic at both levels exhibited significantly improved final body weight, weight gain, specific growth rate, and feed conversion ratio compared to the control group. Digestive enzyme activities (amylase, lipase, and protease) were significantly enhanced in all supplemented groups. Blood biochemical analysis revealed reduced glucose levels and increased total protein in garlic-supplemented groups, with no adverse effects on liver or kidney function markers. Immune parameters, including lysozyme activity, bactericidal activity against Streptococcus agalactiae, alternative complement pathway (ACP), and respiratory burst (NBT), were significantly enhanced in garlic-supplemented groups, with fermented garlic showing more pronounced effects. Antioxidant enzyme activities (SOD, CAT, and GPx) were also significantly increased in all supplemented groups, particularly in those fed fermented garlic. No significant differences in survival rates were observed among treatments. The results suggest that both garlic powder and fermented garlic powder supplementation, especially at the 2% level, can effectively improve growth, feed utilization, immune function, and antioxidant status in L. ramada. Fermented garlic generally demonstrated superior effects, indicating its potential as a beneficial feed additive in aquaculture. Based on these findings, it is recommended to incorporate fermented garlic powder at a 2% level in L. ramada diets to optimize growth performance and health status. Further research is warranted to investigate the long-term effects and cost-effectiveness of this supplementation strategy in commercial aquaculture settings. Full article

(This article belongs to the Section Nutrition and Feeding)

► Show Figures

Figure 1

15 pages, 3918 KiB

Open AccessArticle

Feeding Behavior and Bait Selection Characteristics for the Portunidae Crabs Portunus sanguinolentus and Charybdis natator

by Wei-Yu Lee, Yan-Lun Wu, Muhamad Naimullah, Ting-Yu Liang and Kuo-Wei Lan

Fishes 2024, 9(10), 400; https://doi.org/10.3390/fishes9100400 - 2 Oct 2024

Viewed by 530

Abstract

Understanding the feeding behavior of Portunidae crabs with different baits can improve bait selection and is crucial for improving the effectiveness of crab fishing gear. This study, conducted in indoor experimental tanks, used trajectory tracking software and two types of natural baits (mackerel [...] Read more.

Understanding the feeding behavior of Portunidae crabs with different baits can improve bait selection and is crucial for improving the effectiveness of crab fishing gear. This study, conducted in indoor experimental tanks, used trajectory tracking software and two types of natural baits (mackerel (Scomber australasicus) and squid (Uroteuthis chinensis)) to understand the behavior of Portunus sanguinolentus and Charybdis natator. Spatial distribution results showed that P. sanguinolentus was frequently present in the starting area (S1) and bait area (S3) in the control and treatment groups. However, C. natator was frequently present and concentrated in the S1 area compared to the middle areas S2 and S3, and only in the mackerel treatments were they observed to move to the S3 areas. The spatial distribution results indicate that P. sanguinolentus shows a stronger willingness to explore its surroundings, while C. natator is generally in a stationary, wait-and-see state. The swimming speeds of P. sanguinolentus and C. natator showed different trends. P. sanguinolentus showed continuous movement with no fixed speed when no bait was present in the control groups. However, when treated with mackerel and squid, the average swimming speed of P. sanguinolentus was faster (>5 cm/s) in the first 10 min and showed a more stable movement speed when searching for the baits. C. natator showed a stationary or low movement speed when no bait was present in the control groups. However, when C. natator perceived the presence of the baits in the treatment groups, their movement speed increased in the first 10 min. In addition, there was no significant difference between male and female crabs of P. sanguinolentus and C. natator in movement speed in the control and treatment groups. Compared to C. natator, P. sanguinolentus might be more sensitive to natural baits, as shown by its movement from S1 to S3. The results indicate that the species of Portunidae crabs show different bait selections. Natural baits (mackerel and squid) are recommended for catching P. sanguinolentus in crab fisheries. Full article

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

► Show Figures

Figure 1

16 pages, 4164 KiB

Open AccessArticle

Sea Bass (Dicentrarchus labrax) Tail-Beat Frequency Measurement Using Implanted Bioimpedance Sensing

by Vincent Kerzerho, Mohamed-Moez Belhaj, Serge Bernard, Sylvain Bonhommeau, Tristan Rouyer, Fabien Soulier and David J. McKenzie

Fishes 2024, 9(10), 399; https://doi.org/10.3390/fishes9100399 - 1 Oct 2024

Viewed by 518

Abstract

Estimating tailbeat frequency (TBF) is a crucial component of fish swimming kinematics and performance, particularly because it provides information about energetics and behavioral responses to environmental cues. The most commonly used technique for TBF estimation is based on accelerometers. This paper proposes a [...] Read more.

Estimating tailbeat frequency (TBF) is a crucial component of fish swimming kinematics and performance, particularly because it provides information about energetics and behavioral responses to environmental cues. The most commonly used technique for TBF estimation is based on accelerometers. This paper proposes a novel approach using bioimpedance technology. This is the first time bioimpedance has been measured in a freely moving animal. This was made possible by implanting a flexible electrode in the back muscle of seabasses and having them in a swimming tunnel. The experiment first demonstrates that it is possible to measure bioimpedance in an immersed fish despite the high conductivity of seawater. An agreement analysis was then performed to compare a video-based reference measurement of TBF with the newly proposed approach. Several bioimpedance settings, such as the configuration and the extracted electrical parameters, were considered. Data analysis highlights that a 4-point setup for modulus impedance measurement at frequencies over 10

k

Hz

provides the best agreement (r > 0.98 and CCC > 0.97) with the video-based approach. These results attest to the significant benefits of integrating bioimpedance sensors in biologgers, especially considering the complementary parameters that can be extracted from bioimpedance measurements, such as length, weight, condition index, and fat content. Full article

(This article belongs to the Special Issue Technology for Fish and Fishery Monitoring)

► Show Figures

Figure 1

14 pages, 2494 KiB

Open AccessArticle

Virtual Sensing of Nitrite: A Novel Control for Safe Denitrification in Recirculating Aquaculture Systems (RASs)

by Anneliese Ernst, Christian Steinbach, Kai Wagner and Uwe Waller

Fishes 2024, 9(10), 398; https://doi.org/10.3390/fishes9100398 - 1 Oct 2024

Viewed by 470

Abstract

Recirculating aquaculture system (RAS) technology is seen worldwide as a solution for sustainable fish production. However, there are still deficiencies in the process technology imperiling consistent operation and thus economic results. Drawbacks are linked to essential processes of the water treatment systems such [...] Read more.

Recirculating aquaculture system (RAS) technology is seen worldwide as a solution for sustainable fish production. However, there are still deficiencies in the process technology imperiling consistent operation and thus economic results. Drawbacks are linked to essential processes of the water treatment systems such as denitrification. Nitrogenous waste needs to be removed from RAS process water to maintain an adequate production environment for fish and to mitigate the environmental impact of discharged process water. At present, denitrification lacks reliable process control, especially regarding the organic carbon feed to heterotrophic denitrification processes. An investigation into heterotrophic denitrification in an experimental RAS resulted in the discovery of a virtual sensor based on measurements of the oxidation reduction potential (ORP). The virtual sensor responds to an insufficient carbon feed to denitrification. It is based on the oxidation of nitrite in an ozone-enhanced foam flotation installed downstream of the denitrification. The sensor essentially delivers a binary signal denoting either a complete or an incomplete denitrification process. The virtual sensor can be used for reliably controlling heterotrophic denitrification. It requires an upgraded process chain employing ozone-enhanced foam flotation (protein skimmer) downstream of the denitrification. However, the virtual sensor does not require any additional instrumentation. Full article

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

► Show Figures

Figure 1

12 pages, 1850 KiB

Open AccessArticle

New Documented Records of the Mesopelagic Fish Valenciennellus tripunctulatus (Sternoptychidae) in the Strait of Messina and a Review of Its Mediterranean Occurrences

by Chiara Bacchiani, Giovanni Ammendolia, Sergio De Matteo, Mauro Cavallaro, Emanuela Fanelli and Pietro Battaglia

Fishes 2024, 9(10), 397; https://doi.org/10.3390/fishes9100397 - 1 Oct 2024

Viewed by 390

Abstract

The constellation fish, Valenciennellus tripunctulatus, is a small mesopelagic teleost typically found in equatorial and temperate waters worldwide, although the species has been also rarely recorded in the Mediterranean Sea (less than 20 specimens from the available literature since 1918). The Mediterranean [...] Read more.

The constellation fish, Valenciennellus tripunctulatus, is a small mesopelagic teleost typically found in equatorial and temperate waters worldwide, although the species has been also rarely recorded in the Mediterranean Sea (less than 20 specimens from the available literature since 1918). The Mediterranean records have been documented for the Strait of Messina, the southern Tyrrhenian Sea, the Ligurian Sea and the Adriatic Sea. The present paper offers an updated review on the occurrence of V. tripunctulatus in the Mediterranean basin and provides data on three new specimens, collected in the Strait of Messina between April 2010 and March 2024. Furthermore, we also report information from two individuals found in March 1992 and February 2017, respectively. Overall, the standard length of these specimens ranged from 24.1 to 28.2 mm, whereas weight varied from 0.18 g to 0.20 g. Morphometric and meristic data were reported, and this analysis revealed few differences between examined individuals in the number of PV (ventral series anterior to pelvic fin base) and AC (from anal fin origin to caudal fin base) photophore series. The relationship between total length and standard length (SL = 0.75 × TL + 2.98), total length and head length (HL = 0.17 × TL + 1.47) and standard length and head length (HL = 0.23 × SL + 0.88) showed high correlation values. Considering the lack of data on this species in the Mediterranean, updating morphometric, meristic, biological, ecological and distribution information is very important for taxonomic purposes and useful in understanding the characteristics of the regional population and eventual differences between Mediterranean stock(s) and those from other oceanic areas. Full article

(This article belongs to the Special Issue Mesopelagic Fish Ecology, Biology and Evolution)

► Show Figures

Figure 1

15 pages, 2936 KiB

Open AccessArticle

Rapid Monitoring of Aquatic Organism Biodiversity Based on Environmental DNA in a Medium-Sized Reservoir

by Hui Jia, Mingxia Xia, Tao Zhang and Hui Zhang

Fishes 2024, 9(10), 396; https://doi.org/10.3390/fishes9100396 - 30 Sep 2024

Viewed by 404

Abstract

Environmental DNA (eDNA) has emerged as a highly sensitive and efficient tool for the biomonitoring of aquatic ecosystems. In this study, we investigated fish and benthic species communities using eDNA techniques in a medium-sized reservoir (about 3 square kilometers) in Anhui, China. A [...] Read more.

Environmental DNA (eDNA) has emerged as a highly sensitive and efficient tool for the biomonitoring of aquatic ecosystems. In this study, we investigated fish and benthic species communities using eDNA techniques in a medium-sized reservoir (about 3 square kilometers) in Anhui, China. A total of 12 water samples and 11 sediment samples were analyzed by 12S and 18S primers, respectively. We analyzed the composition of species diversity and the effect of seven environmental factors using the Mantel test. A total of 42 fish taxa were present in the water samples, and 188 benthic taxa in the sediment samples. Species composition was different in disparate stations. We found that water temperature and salinity are pivotal factors influencing the composition of fish communities, while chlorophyll-a is a primary environmental determinant for benthic species assembly structures across different zones. Biodiversity information generated by eDNA techniques can be used to reflect the resource status of this reservoir. The relevant results will provide important scientific reference information for the development and exploitation of medium-sized reservoirs. Full article

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

► Show Figures

Figure 1

17 pages, 3175 KiB

Open AccessArticle

Effects of Climate Change on the Distribution of Scomber japonicus and Konosirus punctatus in China’s Coastal and Adjacent Waters

by Mingxia Xia, Hui Jia, Yibang Wang and Hui Zhang

Fishes 2024, 9(10), 395; https://doi.org/10.3390/fishes9100395 - 30 Sep 2024

Viewed by 458

Abstract

Climate change has increasingly impacted the marine environment, with various marine environmental factors interacting to influence fish distribution. Assessing the impact of climate change on the future distribution of fish depends on understanding how biological responses interact with environmental conditions. Enhancing our understanding [...] Read more.

Climate change has increasingly impacted the marine environment, with various marine environmental factors interacting to influence fish distribution. Assessing the impact of climate change on the future distribution of fish depends on understanding how biological responses interact with environmental conditions. Enhancing our understanding of the potential impacts of climate change is crucial for the sustainable development of marine fisheries. In this study, we analyzed the habitat suitability of Scomber japonicus and Konosirus punctatus in the coastal waters of China (17°–41° N, 107°–130° E) using marine environmental data, including, as follows: sea surface temperature (SST); sea surface salinity (SSS); pH; and biological occurrence data from 2000 to 2010. A maximum entropy (MaxEnt) model was employed to predict the future distribution of these two species based on the shared socioeconomic pathway (SSP) scenarios for 2040–2050 and 2090–2100. The results indicate that climate change will significantly affect the future habitat distribution of S. japonicus and K. punctatus, leading to a decrease in suitable habitat areas offshore China and a gradual shift northeastward in the center of these habitats. These findings are essential for understanding the impacts of climate change on the distribution of S. japonicus and K. punctatus, with significant implications for fisheries resource assessment and management. Full article

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

► Show Figures

Figure 1

12 pages, 2597 KiB

Open AccessArticle

Identification and Characterization of Germ Cell Genes Vasa and Nanos-2 in the Ovary and Testis of White Crappie (Pomoxis annularis) and the Ovary of Black Crappie (P. nigromaculatus)

by Sujan Bhattarai, Nilima N. Renukdas, Anita M. Kelly, Amit Kumar Sinha, Sanjay Joshi and Dayan A. Perera

Fishes 2024, 9(10), 394; https://doi.org/10.3390/fishes9100394 - 30 Sep 2024

Viewed by 462

Abstract

The vasa gene, encoding an ATP-dependent RNA helicase, and the nanos-2 gene, an RNA-binding protein, are essential for germ cell origination, migration, maintenance, and development in vertebrates and invertebrates. The expression levels of the vasa and nanos-2 genes have not yet been investigated [...] Read more.

The vasa gene, encoding an ATP-dependent RNA helicase, and the nanos-2 gene, an RNA-binding protein, are essential for germ cell origination, migration, maintenance, and development in vertebrates and invertebrates. The expression levels of the vasa and nanos-2 genes have not yet been investigated or reported in crappie species. These two genes were partially sequenced and characterized, and their expression patterns were analyzed using reverse-transcription quantitative polymerase chain reaction (RT-qPCR) according to age and sex. The vasa sequences of white crappie (WC) females and males showed significant similarity with the vasa homologs of largemouth bass (Micropterus salmoides; 93.1–93.98%) and smallmouth bass (M. dolomieu; 91.95–92.77%), indicating its conserved nature within the Family Centrarchidae. The vasa sequence of black crappie (BC) females showed significant similarity with the vasa homologs of white crappie (91.67%), largemouth bass (96.10%), smallmouth bass (96.10%), spotted scat (Scatophagus argus; 97.37%), mandarin fish (Siniperca chutasi; 96.15%), Japanese sea bass (Lateolabrax japonicus; 94.87%), lumpfish (Cyclopterus lumpus; 91.95%), southern bluefin tuna (Thunnus maccoyii; 94.74%), large yellow croaker (Larimichthys crocea; 92.21%), and Nile tilapia (Oreochromis niloticus; 92.21%). The nanos-2 sequences of WC females, WC males, and BC females showed significant similarity with the nanos-2 of largemouth bass (92.92–96.36%), smallmouth bass (92.92–96.36%), and mandarin fish (92.66–94.34%). The expression of vasa in BC females was significantly higher at age-2 than at age-1, while WC males and females presented no significant age-related differences. Neither species had a significant difference in nanos-2 gene expression with age. The expression levels of vasa and nanos-2 were significantly higher in WC males than females. Full article

(This article belongs to the Section Genetics and Biotechnology)

► Show Figures

Figure 1

14 pages, 3217 KiB

Open AccessArticle

Effects of Feeding Frequency on Liver Transcriptome: Unveiling Appetite-Regulating Peptides in Mexican Pike Silverside (Chirostoma estor)

by Mitzi Ernestina Juárez-Gutiérrez, Carlos Cristian Martínez-Chávez, Claudia Yaneth Godoy-Figueroa, Verónica Jiménez-Jacinto, María Gisela Ríos-Durán, Carlos Antonio Martínez-Palacios and Pamela Navarrete-Ramírez

Fishes 2024, 9(10), 393; https://doi.org/10.3390/fishes9100393 - 30 Sep 2024

Viewed by 623

Abstract

The Mexican pike silverside (Chirostoma estor) is a zooplanktivorous, agastric short-intestined species, and it has been found that increased-frequency feeding (twelve feedings a day) improved feed efficiency and promoted growth by 70%. This work determined the effect of different juvenile feeding [...] Read more.

The Mexican pike silverside (Chirostoma estor) is a zooplanktivorous, agastric short-intestined species, and it has been found that increased-frequency feeding (twelve feedings a day) improved feed efficiency and promoted growth by 70%. This work determined the effect of different juvenile feeding frequencies upon the C. estor liver transcriptome. The level of the expression of appetite-regulating peptides was analyzed in silico to understand the mechanisms involved in appetite control in this species. Differential expression analysis showed that up-regulated genes between treatments were related to metabolism, digestive processes, immune system response, apoptosis, growth, and oxidative stress. This information explains the better performance of pike silverside fed 12 times daily. Appetite regulatory peptides were identified for the first time in the liver of C. estor in response to high feeding frequencies, contributing to the general knowledge of the roles of each family of neuropeptides in this agastric, short-intestined fish. The information presented here emphasizes the need to explore further the complex physiological processes involved in appetite regulation in C. estor. Additionally, it will serve as a basis for more specific targeted studies of appetite control to elucidate the mechanisms behind this process. Full article

(This article belongs to the Special Issue Advances in Fish Genome and Transcriptomes)

► Show Figures

Figure 1

11 pages, 3123 KiB

Open AccessArticle

Estimating the Purse Seine Net Geometry during a Hauling Operation Using a Data Assimilation Method

by Shintaro Gomi, Tsutomu Takagi, Katsuya Suzuki, Tatsuki Oshima, Shoko Wada, Rika Shiraki, Yoshihiro Nishiyama and Ichiya Ogino

Fishes 2024, 9(10), 392; https://doi.org/10.3390/fishes9100392 - 29 Sep 2024

Viewed by 360

Abstract

The dynamics of fishing nets can be estimated by modeling and numerically computing the forces acting on them. However, the dynamic models of fishing nets are highly nonlinear owing to the significant influence of hydrodynamic forces acting on the net. Therefore, if there [...] Read more.

The dynamics of fishing nets can be estimated by modeling and numerically computing the forces acting on them. However, the dynamic models of fishing nets are highly nonlinear owing to the significant influence of hydrodynamic forces acting on the net. Therefore, if there are unknown parameters that define the state of motion in the model, it is often difficult to achieve high accuracy in the numerical simulations of fishing gear and evaluate its dynamics. To address this issue, a method is proposed for estimating these unknown parameters by integrating a nonlinear Kalman filter into a fishing net dynamics model. This study aimed to estimate the hauling velocity of large- and medium-sized purse seine fishing nets, which can be a challenging parameter to measure. The calculations are based on the data obtained from a research operation conducted by the Marine Fisheries Research and Development Center in 2019 using the purse seine fishing vessel “Taikei Maru No. 1”. The time series of the hauling-net velocity was estimated based on the results of the estimation experiment. These results allowed the estimation of the hauling velocity and calculation of the net dynamics during the hauling process. This shows that net dynamics simulation is possible even with unknown parameters. Full article

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

► Show Figures

Figure 1

17 pages, 4314 KiB

Open AccessArticle

A Study on the Catch Losses and Mesh Selectivity Related to the Attachment of Marine Mammal Bycatch Reduction Devices on Midwater Trawl Gear

by Jung-Mo Jung, Min-Seuk Park and Kyu-Suk Choi

Fishes 2024, 9(10), 391; https://doi.org/10.3390/fishes9100391 - 28 Sep 2024

Viewed by 645

Abstract

The National Institute of Fisheries Science in Korea is developing marine mammal bycatch reduction devices (BRDs) for high-risk fishing gear, such as trawls. We experimented with two BRD types (guiding nets) attached in front of codend at 30° and 45° angles, and catch [...] Read more.

The National Institute of Fisheries Science in Korea is developing marine mammal bycatch reduction devices (BRDs) for high-risk fishing gear, such as trawls. We experimented with two BRD types (guiding nets) attached in front of codend at 30° and 45° angles, and catch losses and mesh size selectivity were investigated. Experimental fishing operations were conducted along the East Coast of South Korea where whales and dolphins are commonly sighted. The catch was classified according to fishing location, BRD type, codend, and covernet, with measurements recorded for body length, maximum girth, and weight. The average selectivity for each haul was analyzed using the ‘selfisher’ package. The catch loss rates with the BRD attached at tilt angles of 30° and 45° were 11% and 29% for common flying squid, 6% and 28% for sailfin sandfish, and 5% and 8% for pearlside. While the mesh selectivity rates for common flying squid and pearlside remained at 0.2–0.5 across all lengths and tilt angles, the mesh selectivity curve for sailfin sandfish was estimated. There were significant differences in catch loss between 30° and 45° angles, with the 30° angle being more effective in catch loss. We observed a masking effect in the codend. Full article

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

► Show Figures

Figure 1

16 pages, 6641 KiB

Open AccessArticle

Assessing the Effects of Guiera senegalensis, Pluchea odorata, and Piliostigma reticulatum Leaf Powder Supplementation on Growth, Immune Response, Digestive Histology, and Survival of Nile Tilapia (Oreochromis niloticus Linnaeus, 1758) Juveniles before and after Aeromonas hydrophila Infection

by Paul M. Ndour, Jean Fall, Maria J. Darias, Domenico Caruso, Marc Canonne, Elodie Pepey, Sophie Hermet, Sokhna K. L. Fall, Malick Diouf and Samira Sarter

Fishes 2024, 9(10), 390; https://doi.org/10.3390/fishes9100390 - 28 Sep 2024

Viewed by 453

Abstract

The effects of three medicinal plants in the feeds of juvenile Nile tilapia (Oreochromis niloticus) were investigated on growth, survival, immunity, and digestive histology at various inclusion levels: (A) Guiera senegalensis at 0, 1, 2, 4, and 8%; (B) Pluchea odorata [...] Read more.

The effects of three medicinal plants in the feeds of juvenile Nile tilapia (Oreochromis niloticus) were investigated on growth, survival, immunity, and digestive histology at various inclusion levels: (A) Guiera senegalensis at 0, 1, 2, 4, and 8%; (B) Pluchea odorata at 0, 0.5, 1, 2, and 4%; (C) Piliostigma reticulatum at 0, 1, and 2%; and (D) a mixture of the three at 0, 1, and 2%. After 28 days of feeding, fish were infected with Aeromonas hydrophila for 12 days. The results showed that, except for G. senegalensis, the inclusion of the medicinal plants, alone or combined, enhanced the immune response. The diet with 4% P. odorata significantly increased plasma lysozyme and bactericidal activities without affecting feed conversion efficiency or growth. Despite improved immunity, none of the treatments enhanced post-infection survival rates. However, fish fed the 1% mixture showed healthier livers and intestines, with reduced cell swelling and normal lipid deposits, followed by the 2% mixture and the control. These results highlight the potential benefits of incorporating P. odorata and the plant mixture into the diets of Nile tilapia juveniles for enhancing their immune response against A. hydrophila. Full article

(This article belongs to the Section Sustainable Aquaculture)

► Show Figures

Figure 1

26 pages, 4521 KiB

Open AccessArticle

Behavioral Characteristics and Related Physiological and Ecological Indexes of Cultured Scallops (Mizuhopecten yessoensis) in Response to Predation by the Crab Charybdis japonica

by Xian Li, Danyang Li, Ying Tian, Yaqing Chang and Zhenlin Hao

Fishes 2024, 9(10), 389; https://doi.org/10.3390/fishes9100389 - 28 Sep 2024

Viewed by 413

Abstract

To investigate the effects of predation by the paddle crab Charybdis japonica on the culture and survival of scallops (Mizuhopecten yessoensis) during bottom culture, we investigated the behavioral characteristics of three sizes (small, medium, and large) of scallops in response to [...] Read more.

To investigate the effects of predation by the paddle crab Charybdis japonica on the culture and survival of scallops (Mizuhopecten yessoensis) during bottom culture, we investigated the behavioral characteristics of three sizes (small, medium, and large) of scallops in response to exposure to crabs. We found that scallops escaped from crab predation by continuous shell closure or movement. Shell closure force increased with scallop size, and scallops of the same size that were stimulated by the presence of crabs closed their shell more frequently than control scallops. We also measured the activities of superoxide dismutase, catalase, arginine kinase, and octopine dehydrogenase in the gill, adductor muscle, and mantle of scallops before and after exposure to predation. Tissues that showed significant differences between control and test specimens were selected for deep sequencing of the transcriptome to identify and validate the key genes that were sensitive to predation. We found that when M. yessoensis is stimulated by the presence of predators, its behavioral characteristics and related physiological and ecological indexes undergo significant changes. The results are relevant for developing specifications for M. yessoensis seedling casting during bottom culture. Full article

(This article belongs to the Section Aquatic Invertebrates)

► Show Figures

Figure 1

Journal Menu

Journal Browser

Fishes, Volume 9, Issue 10 (October 2024) – 49 articles

Further Information

Guidelines

MDPI Initiatives

Follow MDPI