Water

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11 pages, 3392 KiB

Open AccessArticle

Biomanipulation of Periphytic Algae in the Middle Route of South–North Water Diversion Project Canal: An In Situ Study in the Lushan Section

by Xinzong Xiao, Heying Sun, Haiping Ren, Mingxing Xing, Jie Huang, Yingcai Wang, Sheng Hu, Jing Zhang and Jianfeng Tang

Water 2023, 15(12), 2144; https://doi.org/10.3390/w15122144 - 6 Jun 2023

Viewed by 1248

Abstract

The biomanipulation technique has been developed and implemented for decades, yielding favorable results in various lakes both domestically and globally. This technology uses fish to reduce algae biomass, giving a natural and environmentally friendly solution to improve water quality. The effectiveness of biomanipulation [...] Read more.

The biomanipulation technique has been developed and implemented for decades, yielding favorable results in various lakes both domestically and globally. This technology uses fish to reduce algae biomass, giving a natural and environmentally friendly solution to improve water quality. The effectiveness of biomanipulation technology in large-scale artificial water canals, on the other hand, has been unclear. To address this, from 15 December 2019 to 30 April 2020, an in situ experimental study on the biomanipulation of periphytic algae was conducted in the Lushan section of the main canal of the Middle Route of the South-to-North Water Diversion Project (MSNWDP). The study aimed to verify the control effect of fish on periphytic algae. Various combinations of Megalobrama terminalis and Xenocypris davidi were fixed on the canal with a triangular cylindrical cage, and their feeding effects on periphytic algae were observed. The results showed that the density of periphytic algae at the bottom of the cages was substantially lower than before the experiment, with a 68.75% average reduction. We graded the food-filling results based on the amount of digestive tract content, which was represented using Arabic numerals ranging from 0 to 5. The study discovered that M. terminalis had the best adaptability to the environment, with full intestines primarily composed of periphytic algae and a food-filling degree between grades 4 and 5. X. davidi, on the other hand, had a food-filling degree of 0. Furthermore, the weight of each M. terminalis increased significantly following the experiment, whereas the weight of each X. davidi decreased to varying degrees. Additionally, the study highlights the importance of selecting the appropriate fish species for biomanipulation, as different species may have varying levels of effectiveness in controlling periphytic algae. Overall, this study provides valuable insights into the potential of biomanipulation technology in large-scale artificial water canals and other water conservancy projects. Full article

(This article belongs to the Special Issue Ecology of Freshwater Fishes)

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16 pages, 7000 KiB

Open AccessArticle

The Resource Status of Plankton after Stocked Protosalanx chinensis Population Collapse in a Lake of Northeastern China

by Zhe Li, Ying Han, Fujiang Tang, Haoyu Zeng and Yi Zheng

Water 2023, 15(10), 1854; https://doi.org/10.3390/w15101854 - 13 May 2023

Viewed by 1266

Abstract

In order to understand the relative strength of top-down and bottom-up control in lakes of grazing alien fish, Protosalanx chinensis, investigations were designed in Lake Longhu (Lake L, P. chinensis introduced in 2013) and Lake Qijia (Lake Q, P. chinensis free). Plankton samples [...] Read more.

In order to understand the relative strength of top-down and bottom-up control in lakes of grazing alien fish, Protosalanx chinensis, investigations were designed in Lake Longhu (Lake L, P. chinensis introduced in 2013) and Lake Qijia (Lake Q, P. chinensis free). Plankton samples were collected bimonthly through the whole life cycle of P. chinensis (from February to December in 2018). A total of 133 phytoplankton and 68 zooplankton species were recorded in the two lakes. The total density and biomass of phytoplankton and zooplankton were 991.89 × 10⁴ ind/L and 9.2418 mg/L as well as 5212 ind/L and 20.2646 mg/L, respectively. This study revealed that P. chinensis grazing did not deplete the zooplankton resources in the lake where it was stocked. Biodiversity in Lake L was not significantly different from that in Lake Q based on both phytoplankton and zooplankton. Overall, the over grazing of P. chinensis was not found in Lake L. Nevertheless, compared to Lake Q, the correlation between phytoplankton and zooplankton was weakened in Lake L, which meant there were still some effects of stocking P. chinensis on the ecological equilibrium of the plankton community, although no dramatic influences were found in Lake L yet. We also found that P. chinensis and Cladocera were significantly correlated, which should account for the top-down influences. Long-term successive investigations are suggested for sustainable resource utilization and maintaining biological balance. Full article

(This article belongs to the Special Issue Ecology of Freshwater Fishes)

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13 pages, 3578 KiB

Open AccessArticle

Feeding Selectivity and Diet Shift of Protosalanx chinensis during Spring in Lake Dalong, Northeastern China

by Haoyu Zeng, Fujiang Tang, Zhe Li, Wanqiao Lu and Yi Zheng

Water 2023, 15(10), 1847; https://doi.org/10.3390/w15101847 - 12 May 2023

Cited by 2 | Viewed by 1140

Abstract

Ontogenetic niche shifts have played an important role in the life history and ecological functions of fish. The clearhead icefish (Protosalanx chinensis, Basilewsky, 1855) is a small, pelagic, and commercially important fish that mainly feeds on zooplankton and will transition to [...] Read more.

Ontogenetic niche shifts have played an important role in the life history and ecological functions of fish. The clearhead icefish (Protosalanx chinensis, Basilewsky, 1855) is a small, pelagic, and commercially important fish that mainly feeds on zooplankton and will transition to feeding on fish when prey fish are available, though its life span is only about one year. In fact, we know little about the food selectivity and diet shifting of P. chinensis before its transition to feeding on fish. To reveal the food selectivity of P. chinensis before its transition to feeding on fish, the gut contents and environmental zooplankton community were investigated simultaneously in Lake Dalong of Northeastern China from April to June 2021. The results showed that P. chinensis experienced a diet shift from copepoda to cladocera during spring in Lake Dalong. From April to early June, both the size of cladocera and copepoda in guts increased as the size of P. chinensis increased. However, the favorite category changed to the smaller cladocera in late June, when the density of the smaller cladocera was rather high relatively. Considering June was the critical period for P. chinensis to prepare for transitioning to feeding on fish, the food resources availability must be seriously considered for sustainable aquaculture of P. chinensis. It was hypothesized that there was a trade-off of feeding selectivity between the size and density of the prey. Full article

(This article belongs to the Special Issue Ecology of Freshwater Fishes)

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15 pages, 3362 KiB

Open AccessArticle

A Review of the Age, Growth Characteristics, and Population Resources of Ptychobarbus dipogon in the Middle and Upper Reaches of the Yarlung Zangbo River

by Wenjia He, He Gao, Chaowei Zhou, Wanliang Wang and Yanchao Liu

Water 2023, 15(9), 1713; https://doi.org/10.3390/w15091713 - 28 Apr 2023

Viewed by 1306

Abstract

This paper applies the von Bertalanffy growth equation to study the age structure and growth characteristics of 210 Ptychobarbus dipogon collected in September 2019 in the middle and upper reaches of the Yarlung Zangbo River and employs FISAT II software to estimate the [...] Read more.

This paper applies the von Bertalanffy growth equation to study the age structure and growth characteristics of 210 Ptychobarbus dipogon collected in September 2019 in the middle and upper reaches of the Yarlung Zangbo River and employs FISAT II software to estimate the population characteristics’ parameters. Its aim is to provide a basis for the conservation of the population resources of the Ptychobarbus dipogon. In this study, the length of the catch ranged from 137 mm to 475 mm, the weight ranged from 44.04 g to 1142.80 g, the minimum age was 5 years, and the maximum age was 47 years. The body length–weight relationship was W_(♀) = 4.1738 × 10⁻⁵L^2.7687 (n = 86, R² = 0.901); W_(♂) = 2.7784 × 10⁻⁵L^2.8434 (n = 100, R² = 0.918). The growth equation was Lt_(♀) = 505.000[1 − e^{−0.048(t−1.992)}]; Lt_(♂) = 452.254[1 − e^{−0.069(t−4.233)}]; Wt_(♀) = 1296.576[1 − e^{−0.048(t−1.992)}]^2.7687; Wt_(♂) = 1001.872[1 − e^{−0.069(t−4.233)}]^2.8434. The inflection point ages of the female and male Ptychobarbus dipogon were 7.95 and 6.05, respectively. The exploitation rate of Ptychobarbus dipogon was 0.61, which exceeds the optimum exploitation rate of resources (0.57). The population resources are overfished. It is suggested to strengthen the conservation of Ptychobarbus dipogon population resources and the protection of native fish on the Qinghai–Tibet Plateau. Full article

(This article belongs to the Special Issue Ecology of Freshwater Fishes)

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12 pages, 1996 KiB

Open AccessArticle

Analysis of Genetic Diversity in Coilia nasus Based on 2b-RAD Simplified Genome Sequencing

by Yu Li, Jianhua Chen, Guangpeng Feng, Qingyun Wang, Rulong Xia, Chao Song, Haihua Wang and Yanping Zhang

Water 2023, 15(6), 1173; https://doi.org/10.3390/w15061173 - 17 Mar 2023

Cited by 1 | Viewed by 1508

Abstract

In the protection of migratory species, Coilia nasus has always been a research topic of very high interest in various countries because of the high economic value and the serious decline of resources. In this study, C. nasus were collected from the Shengsi [...] Read more.

In the protection of migratory species, Coilia nasus has always been a research topic of very high interest in various countries because of the high economic value and the serious decline of resources. In this study, C. nasus were collected from the Shengsi Sea area, the Yangtze River estuary, the Taizhou section of the Yangtze River and Poyang Lake. By using 2b-RAD simplified genome sequencing technology, 63,110 SNP sites were screened, and the genetic diversity of each population was analyzed with SNP markers. The results showed that (1) the genetic purity of the four groups of populations was not high, with the need to further increase levels of genetic purity; (2) the genetic diversity in the four populations was high, indicating that they had strong adaptability to environmental changes and could easily expand their distribution and resource growth; (3) the F_ST values (0.112–0.142) of the four populations were higher, indicating that there was moderate genetic differentiation, but no independent population was formed. This study speculated that these migratory species may have the same spawning grounds and pointed out that the gene purity of C. nasus may have been polluted, and it is urgent to improve the purity in the protection of migratory C. nasus. Full article

(This article belongs to the Special Issue Ecology of Freshwater Fishes)

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16 pages, 3110 KiB

Open AccessArticle

Effects of Shelter on the Hatching, Immune Performance, and Profitability of the Ovigerous Red Swamp Crayfish Procambarus clarkii under High Stocking Density

by Lirong Qin, Chao Guo, Mantang Xiong, Kun Gong, Jiashou Liu, Tanglin Zhang and Wei Li

Water 2023, 15(5), 907; https://doi.org/10.3390/w15050907 - 26 Feb 2023

Viewed by 1629

Abstract

To develop the intensive breeding technology of the seed of the red swamp crayfish Procambarus clarkii, the survival rates, hatching effects (hatching rate, incubation level, and number of juveniles), and immune performance of ovigerous P. clarkia as well as economic benefits are [...] Read more.

To develop the intensive breeding technology of the seed of the red swamp crayfish Procambarus clarkii, the survival rates, hatching effects (hatching rate, incubation level, and number of juveniles), and immune performance of ovigerous P. clarkia as well as economic benefits are evaluated under different shelter conditions under a high stocking density in this study. The experimental design includes three different forms of shelter treatments (D1: experiment without any shelters; D2: experiment with closed shelters; D3: experiment with open shelters), each with three replicates. The results show that the concentration of the total antioxidant capacity (T-AOC) and activities of phenoloxidase (PO), catalase (CAT), and acid phosphatase (ACP) in the D3 treatment are higher than those in the D1 treatment (all p < 0.05), with the highest concentrations of total antioxidant capacity (T-AOC) and malondialdehyde (MDA) and the highest activities of phenoloxidase (PO), superoxide dismutase (SOD), catalase (CAT), acid phosphatase (ACP), and alkaline phosphatase (AKP) among the treatments being present in the ovigerous P. clarkii in the D3 treatment. The hatching rates of the three treatments vary from 69.51% to 94.28%, with the highest rate found in the D3 treatment and the lowest in the D1 treatment, but there is no significant difference among them (p > 0.05). The highest incubation level (ind.·m⁻²) and the highest number of juveniles (ind.·m⁻²) among treatments are found in the D3 treatment, with the incubation level (ind.·m⁻²) in the D3 treatment being significantly higher than that in the D1 treatment (p < 0.05). The benefit–cost ratios (BCRs) of the D2 and D3 treatments remain significantly higher than that of the D1 treatment when P. clarkii prices change (all p < 0.05). Our results indicate that a high stocking density habitat with open shelters could effectively improve the hatching and immune performance of ovigerous P. clarkii. Our findings are relevant for the indoor aquaculture management of ovigerous P. clarkii. Full article

(This article belongs to the Special Issue Ecology of Freshwater Fishes)

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10 pages, 868 KiB

Open AccessArticle

Niche Analysis of the Main Fish in the Lhasa River Basin

by He Gao, Haiping Liu, Qiming Wang, Fei Liu, Junting Li, Yuting Duan, Luowu Zeren, Suxing Fu, Jingsen Zhang, Yan Zhou, Yan Li and Chaowei Zhou

Water 2023, 15(5), 860; https://doi.org/10.3390/w15050860 - 23 Feb 2023

Cited by 2 | Viewed by 1966

Abstract

The Lhasa River is one of the five tributaries of the Yarlung Zangbo River. It is the main industrial, agricultural and animal husbandry area in Tibet. It plays an important ecological security barrier role in regulating regional climate and maintaining biodiversity. In order [...] Read more.

The Lhasa River is one of the five tributaries of the Yarlung Zangbo River. It is the main industrial, agricultural and animal husbandry area in Tibet. It plays an important ecological security barrier role in regulating regional climate and maintaining biodiversity. In order to understand the resource utilization ability and relationship of fish in Lhasa River, and provide basic data for the protection and sustainable utilization of fish diversity in Lhasa River, the fishery resources in September 2019 (autumn), June 2020 (summer), November 2020 (winter) and March 2021 (spring) were investigated for the first time. The main fish in the catch were determined by the Index of Relative Importance (IRI). Shannon index and Pianka’s index were used to analyze the niche breadth and overlap values of the main fish caught in Lhasa River Basin from three dimensions of time, space and space–time. The results show that a total of 1399 fish of 3 orders and 4 families were collected. Among them, there is one dominant species, Schizopygopsis younghusbandi, and five common species, Schizothorax waltoni, Schizothorax oconnori, Ptychobarbus dipogon, Triplophysa stenura and Carassius auratus. The spatial–temporal niche breadth ranges from 1.395 to 3.628. They are Schizopygopsis younghusbandi, Carassius auratus, Ptychobarbus dipogon, Schizothorax oconnori, Triplophysa stenura and Schizothorax waltoni in a declining order. The temporal niche breadth is generally small, indicating that the survival activities of the main fish are greatly affected by seasonal changes. The fluctuation range of spatial–temporal overlap value is 0–0.535, and only 20% of the total logarithm is meaningful. The species pairs with temporal niche overlap values exceeding 0.300 reached 80%, while the spatial niche overlap value is generally low. The results show that the spatial and temporal distributions of the main fish in Lhasa River were quite different, and the spatial and temporal niche overlap value of the relationship between species is obviously affected by the change in spatial distribution. This demonstrates that the competition relationship and intensity of the main fish are quite different in different spatial positions. Full article

(This article belongs to the Special Issue Ecology of Freshwater Fishes)

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16 pages, 9384 KiB

Open AccessArticle

Effect of Different Land Use Types on the Taxonomic and Functional Diversity of Macroinvertebrates in an Urban Area of Northern China

by Aoran Lu, Jiaxin Li, Biao Zheng and Xuwang Yin

Water 2022, 14(23), 3793; https://doi.org/10.3390/w14233793 - 22 Nov 2022

Cited by 1 | Viewed by 2396

Abstract

The urbanization of riverine landscapes is an increasing threat to river ecosystems. However, it is unclear which metrics can best assess the response of macroinvertebrates to the conversion of forested lands to urban and agricultural lands. The main goal of this study is [...] Read more.

The urbanization of riverine landscapes is an increasing threat to river ecosystems. However, it is unclear which metrics can best assess the response of macroinvertebrates to the conversion of forested lands to urban and agricultural lands. The main goal of this study is to examine whether trait-based approaches are more sensitive than taxonomic approaches in distinguishing macroinvertebrate responses to different land use types in a highly urbanized area of northern China. Results based on 14 environmental variables showed a significant difference across a human-induced environmental gradient. The results showed that no significant differences were observed in terms of taxonomic diversity indices between the different land use types. Functional evenness (FEve) and Rao’s quadratic entropy decreased with the increase in urban area caused by the intensification of human activity, demonstrating that functional diversity is more sensitive than taxonomic diversity in discriminating between different land use types. In addition, the results based on RLQ (physical–chemical variables (R), macroinvertebrate taxa (L), and species traits (Q)) and fourth-corner analyses indicated that the trait states of bi- or multivoltine, high dispersal capacity, and not-streamlined body shape were much higher in the agricultural area and positively related to farmland percentage. Taxa with large body size were dominant in urban areas and were positively correlated with EC. Overall, the observed responses of traits to environmental variables suggest that trait-based approaches should be incorporated into land use management for river restoration. Full article

(This article belongs to the Special Issue Ecology of Freshwater Fishes)

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