Fish In Water Bodies Research Articles

Видовой состав паразитов крови рыб (Pisces) водоемов Волгоградской области: обзор исследований

The aim of this article is generalization of literary sources on blood parasites of fish in water bodies of the Volgograd region and determination of species composition. The material for the study was all the publications available to the authors on fish blood parasites in the Volgograd region. Methods used: comparative data analysis, descriptive statistics methods. Results indicate that the fish blood parasite fauna includes about 18 species belonging to 2 types (Euglenozoa, Sporozoa), 2 classes (Kinetoplastidea, Coccidea), 3 families (Cryptobiidae, Trypanosomatidae, Haemogregarinidae), and 3 genera. In view of the lack of reliable information about the findings of Cryptobia barbiand Trypanosoma acerinae in the blood of fish from the Volgograd region, their habitation in the study area is debatable. This report is preliminary, and the proposed species composition needs to be clarified. Practical significance: the obtained information can be used as a guide for the study of the parasite fauna of commercial fish species in the reservoirs of the Volgograd region, the implementation of preventive measures, and the monitoring of the epidemiological situation in the region.

Dynamics of the parasitofaauna of roach Rutilus rutilus (Linnaeus, 1758) since the beginning of the existence of the Boguchanskoye reservoir

This article presents the results of parasitological studies of roach Rutilus rutilus (Linnaeus, 1758) in Boguchanskoye reservoir, the stages of parasite fauna formation and the current state of the reservoir. Ichthyofauna of Boguchanskoye Reservoir was formed by local fauna of Angara River. Transformation of the original reservoir has led to significant changes in the composition and community structure of all groups of organisms of aquatic biota and affected the parasite fauna of fish. Over eight years (2012–2020), 35 species of parasites from 9 classes were recorded in roach in Boguchanskoye Reservoir. Originally, the composition of parasites was not diverse and had few specific species. Most parasites had low or single occurrence. Trematode metacercariae predominated, and their quantitative indicators (extensity of infection and index of abundance) indicate the ecological confinement of fish to shallow river sections. After impoundment, the parasite fauna composition became more diverse due to parasitic protozoa and monogeneas. Currently, the proportion of parasites with a direct development cycle is 68.2%. In 2020, two types of helminths were registered with a plankton development pathway: Ligula intestinalis Linnaeus, 1758 and Philometra rischta Skrjabin, 1917. The species Ph. rischta — first detected in fish in water bodies of Krasnoyarsk Region. There was a change in the dominant species, Dactylogyrus crucifer (Wagener, 1857) became the dominant species.

Evaluation and refinement of a fish movement model for a tropical Australian stream subject to mine contaminant egress

The impacts of mine contaminants on ecological connectivity in rivers and streams are poorly documented globally. We used acoustic telemetry to evaluate and refine conceptual models of fish movement in Magela Creek, a stream in the wet-dry tropics of Australia. This creek receives wastewater discharge from a nearby uranium mine, and a secondary objective was to describe behavioural responses of fish to one such discharge event. Of 55 fish (black bream Hephaestus fuliginosus, saratoga Scleropages jardinii, sharp-nose grunter Syncomistes butleri) tagged in dry season refuge pools 18 km upstream of the mine lease area (RPA [Ranger Project Area]), 16 (29%) moved downstream after the first wet season flows, using the RPA as habitat for 3–5 months before moving upstream to their previous locations as flows receded. Of 39 fish (spangled perch Leiopotherapon unicolor, barred grunter Amniataba percoides, black catfish Neosilurus ater) tagged ~ 8–12 km downstream of the RPA in the late wet season, only two were subsequently detected in the RPA. Direct and camera-based observations of 12 species of upstream-migrating fish during mine-water discharge in the late wet season showed no evidence of mine-water avoidance. Our results demonstrate that Magela Creek provides wet season habitat for fish within the RPA and acts as a migration pathway that connects lowland reaches and floodplains to upstream dry season refuges. Use by fish of waterbodies within the RPA highlights the need to manage the site to ensure that future contaminant egress and water quality do not adversely affect fish migration and habitat suitability.

The effect of chemical exudates of three larvivorous fish species on oviposition preference of Aedes aegypti and Aedes albopictus (Diptera: Culicidae).

Mosquito species Aedes aegypti and Aedes albopictus are vectors of dengue worldwide. Mosquito vector control through maintaining larvivorous fish in water bodies is generally suggested, however, its underlying role towards oviposition preference of these dengue vectors is unknown in the Sri Lankan context. The current study investigated the effect of chemical exudates from larvivorous fish species Poecilia reticulata, Rasbora daniconius and Applocheilus dayi on the oviposition preference of Aedes mosquitoes. The number of eggs laid by each mosquito species was determined using ovitraps that contained water conditioned by the fish species both separately and in combination. The ovitraps were placed inside insect cages containing engorged gravid Aedes females. Both the mosquito species had the least preference of oviposition in water conditioned by A. dayi followed by R. daniconius. The highest preference of oviposition was shown for water conditioned by P. reticulata. The current study indicated that oviposition site selection in Ae. aegypti and Ae. albopictus was reduced by A. dayi and R. daniconius, however, it was not influenced by the fish combinations used. Further studies are warranted to understand the chemical cues associated with larvivorous fish towards the oviposition preference in Aedes mosquitoes.

101 lakes - lentic fish community monitoring using eDNA metabarcoding

We have recently developed and deployed methods for environmental DNA (eDNA) based monitoring of lake fish communities in the UK. This approach combines eDNA with modern High-Throughput-Sequencing technology, so-called eDNA metabarcoding. This non-invasive method has proven to be more effective at detecting elusive species than established invasive surveying techniques such as electro fishing or fyke netting and can provide meaningful semi-quantitative abundance estimates. The UK Environment Agencies have funded the collection of an eDNA meta-barcoding data set of vertebrates from 101 UK lakes covering a broad spectrum of environmental conditions Fig. 1. This dataset is based on analysing 20 water samples per lake and has successfully been used to develop a WFD compatible water quality assessment tool. In its current form this tool is suitable for reporting the status of fish in water bodies where eutrophication is the dominant pressure. DNA is not homogeneously distributed in lentic environments and hence the detection of species relies on the collection of an adequate number of samples from a water body to capture the eDNA signal. Previous analyses on a subset of lakes have indicated that the number of samples used for the 101 lake fish data set is more than sufficient to reliably estimate species richness of lakes, but it is unclear how exactly reduced sampling effort affects other biodiversity estimates and inferences made about water quality. As the number of samples determines the cost of monitoring programmes it is essential that the sampling effort is optimised for a specific monitoring objective. The objective of this study was to explore the effect a reduced sampling effort would have on various biological inferences using algorithmic and statistical resampling techniques. with a much lower number of samples. For example, almost 90% of lakes achieved a sample coverage of 95% with only 10 samples. However, rare species are more often missed with fewer samples, with implications for monitoring programs of invasive or endangered species. Estimates of community composition and the ecological quality ratio (EQR) responded slowly to decreasing sampling effort. For example, subsets of 10 samples were in most cases much more closely related to each other than to sample sets from other lakes and showed very similar Ecological Quality Ratios. These results are able to inform the design of eDNA sampling strategies, so that these can be optimised to achieve specific monitoring goals.

Distribution and bioaccumulation of heavy metals (Hg, Cd and Pb) in fish: influence of the aquatic environment and climate

Mercury (Hg), cadmium (Cd) and lead (Pb) are toxic metals that continue to attract much attention because they are prone to be accumulated in fish tissues and can harm human health if taken up with food. Data acquired by studying the bioaccumulation of these metals in the various fish species from water bodies along a latitudinal gradient in Russia (from northern Arctic lakes to the southern mouth segments of the Volga River) are utilized to identify general tendencies and specifics in the accumulation of toxic metals depending on the aquatic environment and temperature. Results demonstrate that small quantities of the metals are accumulated in various functionally important organs: Hg is enriched in the liver and muscles, Cd in the kidneys and gills, and Pb in the kidneys and liver. The metals are proved to be simultaneously accumulated in all organs and tissues of the organism, and this reflects the uptake of the metals by the organism and their subsequent distribution in it. The aquatic environment and fish habitats affect the elements’ bioavailability. The metals are more significantly accumulated in predatory fish. At low Hg concentrations in the water, statistically significant dependences were identified between Hg accumulated in predatory fish organisms and concentrations of organic matter in the water. Cd is more bioavailable in waters with low pH. Pb displays the strongest dependence of its bioaccumulation in low-salinity water. Extensive data on fish in water bodies occurring in large territories in Russia, from the Arctic to warm southern latitudes, indicate that climate affects the intensity of Hg accumulation, whereas the accumulation of the other metals also depends on the Ca concentrations, with the uptake of these metals being more significant at low Ca concentrations. Concentrations of toxic metals in the muscles of the fish were below the values critical to food to be consumed by humans.

Estimation of natural reproduction efficiency of semi-anadromous and river fish species in inland water bodies of the Republic of Dagestan, Russia

Aim. Estimation of the natural reproduction efficiency and patterns of formation of fish stocks.Material and Methods. Collection of material was carried out in 2010-2019 in inland water bodies in Dagestan and its shallow Caspian Sea coastal zone. Estimation of the number of juveniles in rivers and canals was carried out using ichthyoplankton cone seines. Fry seines were used to count juveniles of fish in water bodies and in the coastal area. 470 samples of juveniles were collected and 5640 juveniles were analysed. The collection and processing of materials were carried out according to generally accepted methods.Results. The main environmental factors determining the productivity of fish juveniles in the study area in the long-term have been identified. During the observation period, juvenile fish of 15 species were recorded in spawning grounds of inland water bodies. Roach, bream, carp, crucian carp, rudd and vimba bream dominate. In terms of numbers, roach juveniles predominate: their relative proportion being 31.02% with an increase from 27.1% in 2010 to 35.4% in 2018.The second place was occupied by bream juveniles, whose average relative proportion was 12.1%. The third place was occupied by carp juveniles with an average proportion of 9%. Juvenile zander, catfish, pike and kutum are relatively low in abundance from 2 to 4%. The yield of juvenile fish in 2010-2019 decreased 1.7 times compared to 1990-1995.Conclusion. It was established that a decrease in the number of juvenile fishes occurs under the influence of unfavorable environmental factors: decrease in sea level; reduction in spawning areas; the shallowing and silting of migration routes due to the lack of a stable water supply. Measures are proposed to improve the living conditions of aquatic biological resources, aimed at increasing the efficiency of their natural reproduction.

Assessment of the Hydrochemical Regime and Safety of Fish in Water Bodies of Karaganda Region, Kazakhstan

Assessment of the Hydrochemical Regime and Safety of Fish in Water Bodies of Karaganda Region, Kazakhstan

Fish in water bodies of the Emerald Network of Ukraine

The paper provides information on the structure of sites of the Emerald Network of Ukraine as special areas of conservation, focused at ensuring the protection of natural fauna, flora and habitats. The development of this network was initiated for the implementation of a set of resolutions of the Berne Convention (1979), and principles of its formation are basically similar to Natura 2000. As of 2019, a total of 271 Emerald sites were designated in Ukraine. According to studies, the water bodies of the network are inhabited by 25 fish species. The data were extracted from up-to-date ichthyological publications on the distribution of fish species in Ukrainian water bodies, catalogues of collections of various zoological museums, regional faunal cadastres, and own research. Analysis of the fish species composition in the sites has shown that the most common and found in more than 60% of the sites are Cobitis taenia, Rhodeus sericeus amarus, Misgurnus fossilis. This can be explained by characteristics of their biology and tolerance to environmental conditions. Endemic species are extremely rare in the Emerald sites and narrowly localized in several river basins. In particular, they are Zingel zingel, Umbra krameri, Eudontomyzon danfordi, Hucho hucho, and Leuciscus souffia recorded in 5-6 sites of the network. Further research is required that will be focused at the development of an integral network of Emerald sites in Ukraine. For this purpose, ichthyological reserves of general and local significance may be considered as promising areas. The analysis of the species number and distribution in water bodies of Ukraine is quite relative and requires additional special field studies. In addition, a qualitative assessment of the number of fish species in promising areas requires ichthyological research methods to be unified and an effective monitoring system be introduced.

137Cs in Higher Aquatic Plants and Fish of Water Bodies of Ukraine

137Cs in Higher Aquatic Plants and Fish of Water Bodies of Ukraine

MODELING THE DIRECT AND INDIRECT EFFECTS OF POLLUTANTS ON THE SURVIVAL OF FISH IN WATER BODIES

Several sources of water pollution are causing negative consequences to marine life. The organisms that are more affected are fishes and marine mammals since they are at the top of the food chain. They are directly exposed to high levels of toxins in water and/or they feed on other fishes that are contaminated. Unfortunately, the main cause of the contaminations, and thus of the fish deaths, come from human activities, such as industry, agriculture, municipal wastewater and solid wastes. The present study is concerned with the effect of organic and inorganic pollutants on the survival of fish in water bodies. We introduce a nonlinear mathematical model by considering five interacting variables; organic pollutants, inorganic pollutants, bacteria, dissolved oxygen and fish in the water body. The model is analyzed using the stability theory of differential equations and to confirm the analytical findings, numerical simulations are performed. Our results suggest that to maintain water quality and to save fish life, the global community has to limit the release of organic and inorganic pollutants into the aquatic system.

Radiation-induced cytogenetic and hematologic effects on aquatic biota within the Chernobyl exclusion zone

During 1998–2014 the rate of chromosomal aberrations in embryo tissues of the pond snail (Lymnaea stagnalis) and root meristems of higher aquatic plants, and also hematologic indexes of mantle liquid of the adult snails and peripheral blood of fishes in water bodies within the Chernobyl exclusion zone (EZ) was studied. The absorbed dose rate for hydrobionts from water bodies of the EZ registered in a range from 0.25 to 420 μGy h−1 and in the reference ones – up to 0.09 μGy h−1. The level of chromosomal aberrations in the molluscs from the most contaminated water bodies of the EZ was registered within range of 18–27% and for the molluscs from the reference lakes this index was on the average 1.5% with the maximal values 2.3%. The rate of chromosomal aberrations in root meristematic cells of higher aquatic plants from the contaminated lakes of the EZ was in range of 7–17% and in the plants from reference water bodies was not exceed 2.1%. The positive correlation between chromosomal aberration rate and absorbed dose rate in the pond snail's embryos and root meristems of higher aquatic plants in water bodies of the EZ was registered. Analysis of hemolymph structure of snails from the most contaminated water bodies showed a high rate of dead and phagocytic cells as well as decrease of the young amoebocytes quantity. Hematologic research of fish allows to determine on the one hand an insignificant changes of leukogram structure, and from the other hand a high level of red cells with different abnormalities in the peripheral blood of fishes from the water bodies with high levels of radioactive contamination. It is suppose that qualitative indexes of red cells in peripheral blood of fish are more sensitive to long-term radiation impact in comparison with elements of white blood, which can be used for conducting of the hematologic monitoring of radioactive contaminated water bodies.

Morphofunctional transformations in fishes of the middle and lower Ob’ basin under increasing anthropogenic influence

The results of a long-term (1981–2009) study on the gametogenesis and sexual cycles are given, and the state of gills and liver is characterized in Coregonidae, Cyprinidae, and Percidae fishes in waterbodies of the Ob’-Irtysh Basin considered intact and in those affected by anthropogenic influence to various degrees. The resistance to pollution of the branchial epithelium, liver, and gonads in fishes is shown to decrease in the following sequence: cyprinids → percids → coregonids → juvenile coregonids. Specific features of the composition and quantitative dynamics of primary sexual cells during the embryonic and early postembryonic periods are described in different coregonid species. The influence of weak pulsed electromagnetic fields on coregonid embryos and larvae has been analyzed with the purpose of developing methods for increasing the ecological plasticity under extreme natural and technogenic conditions.

Mercury concentration in ecosystem components in water bodies and streams in Khanh Hoa province (Central Vietnam)

Total mercury concentration in water, seston, soils, and muscle tissues of fish in water bodies in Khan Hoa province was determined. Hg concentration in water does not exceed 40 ng/l. It migrates in water mostly in dissolved form. Hg concentration in soils of the examined water bodies varies from 0.01 to 0.05 mg/(kg dry mass) and that in the muscle tissues of fish on the average does not exceed 1.4 mg/(kg dry mass).

The importance of fish stocking in the dissemination of parasites throughout a group of reservoirs

In view of the known importance of anthropochore movements of fish in disseminating their parasites, it was hypothesized that local movements of fish between neighbouring water bodies for stocking and management purposes would similarly disseminate their parasites, resulting in a high degree of similarity in the parasite communities of fish in water bodies that have been linked by fish transfers. This hypothesis was tested by comparing the helminth parasite communities in brown trout, Salmo trutta Linnaeus and rainbow trout, Oncorhynchus mykiss (Walbaum), in reservoirs in south west England. In one group of six reservoirs there is a recent history of transfers of rainbow trout, and in the second group of four there have been no transfers over the last decade. There was no difference in mean similarity, using Jaccard's Coefficient and a Percentage Similarity Index, between the helminth faunas of trout in the reservoirs linked by transfers and those not so linked, and the distribution of several individual species of helminths was not consistent with their having been disseminated in the course of fish stockings. The hypothesis is thus rejected and it is concluded that anthropochore transfers of trout between reservoirs have been of little or no significance in the dispersal of parasites throughout the reservoirs or in the transfer of helminths from one reservoir to another. The reasons for this unexpected conclusion are discussed in the light of indications that factors unrelated to fish transfers were important determinants of helminth community composition in individual reservoirs.