Feeding of Burbot Lota lota in Modern Conditions of the Kuybyshev Reservoir

Abstract: The feeding of burbot Lota lota was studied in the modern conditions of the Kuibyshev Reservoir. With the decrease in the abundance of ruff Gymnocephalus cernuus in the reservoir, gradual establishing of gobies (Gobiidae) within the ruff range began. Recently, gobies form the basis of the of burbot diet. The dominance of alien species in the diet of burbot indicates that this predator may play the role of a regulator of the number of invasive fish species and of a biological ameliorator in waterbody

The impact of herbivorous fish introduction on the formation of fish communities in water bodies (based on the Khauzkhan Reservoir, Turkmenistan)

The dynamics of the structure of fish species complex in the community of the Khauzkhan Reservoir (Turkmenistan) has been analyzed from the time when it was filled in 1966 to 1990. In order to quantify the observed changes in the fish population, the indices of diversity and dominance and the dynamic phase portrait method have been used and the structural changes have been visualized. Changes in the dominant complex of species and the dynamics of the relative abundance in the catches of fish groups belonging to different faunal complexes and ecological groups have been also considered. A relation between the changes in the structure of fish species complex in the community under study and the changes in the ecosystem of the reservoir has been found. It has been shown that the introduction of herbivorous fish from the first years of the reservoir filling has resulted in a new stage in the formation of its ichthyofauna, which is known as the stage of acclimatization, and in the extension of the formation process. Currently, the fish population of the Khauzkhan Reservoir is at the 4th stage of formation – the stage of an increase in the anthropogenic impact

Polycyclic aromatic hydrocarbons in bottom sediments of an inner-city lake in the zone of discharge of surface runoff

© 2020 Published under licence by IOP Publishing Ltd. The study determined the content of polycyclic aromatic hydrocarbons (PAHs) in the bottom sediments of an inner-city Sredny Kaban Lake (Kazan, Russia) in the places of the organized release of untreated surface stormwater runoff within the catchment of the city. The content of 15 PAHs included in the priority list of PAHs for environmental research in the Russian Federation and in other countries was experimentally studied. The average content of the total PAHs studied (333.4 μg/kg) in the bottom sediments of the lake indicates a low degree of pollution. The analysis of the ratio of the content of individual PAHs reveals the main sources of their entry: Fuel combustion (vehicles) and oil pollution of the surface water. Benzo(g,h,i)perylene and Benz(a)pyrene represent the largest contribution to the hazard coefficient of all studied PAHs for bottom sediments of the studied water body. Bottom sediments are composed mainly of particles with a size of 1-100 μm; the contribution of particles with a size of 0.1-1 μm was estimated to be up to 1%

Quantitative assessment of biogenic elements and suspended matter load to inner-city river: The role of point sources and diffuse runoff

The article provides a quantitative assessment of the input of biogenic elements and suspended matter in the composition of the storm sewer outlets from the territory of the Kazan City (Russia, the Republic of Tatarstan) and the diffuse runoff of biogenic elements from the agro-developed catchments into the Kazanka River (left tributary of the Volga River) as the main risk factors for the development of anthropogenic eutrophication processes. Based on the results of long-term monitoring and the current background concentrations of total phosphorus, nitrogen and suspended solids in the recipient river, determined in the work, the impact of storm water discharge on surface waters within the Kazan City was assessed. The values of permissible loads of phosphorus and nitrogen mineral fertilizers on an agriculturally developed catchment are given for regulating the diffuse runoff of nutrients into a water body, depending on the hydrometeorological conditions of the territory, to a level that meets the basic environmental requirements for the quality of surface waters

Comparative Analysis of Biodamage to Various Types of Polyethylene by Galleria mellonella (Insecta, Lepidoptera, Pyralidae) Larvae

© 2020, Pleiades Publishing, Inc. Abstract—A comparative analysis of the ability of G. mellonella larvae to wreak biodamage on polyethylene of various types was carried out. Fifteen polyethylene (PE) samples of three types differing in their characteristics were studied: type 1 (PE-1) was a package for food products (Petrothene LR 7340), type 2 (PE-2) was an AIRplus air package for nonfood goods (Hostalen GF 4750), and type 3 (PE-3) was a household package for purchases (NPE 953). The eating rate of these types of polyethylene was up to 1.078 mg larva–1 day–1 (by weight) and up to 61.8 mm2 larva–1 day–1 (by square). The largest number of perforations formed was observed in the PE-1 sample—0.857 units larva–1 day–1. Although PE-1 was preferred in this experiment, the greater wax moth larvae ate all PE types. The majority of larvae in the control and experimental groups were active without stimulation, but some larvae showed activity after stimulation. No processes of melanization of the external integument of G. mellonella larvae were observed in any of the groups. The results of survival rates, mobility, weight gain, and melanization processes indicate no negative effects on the health of larvae when eating polyethylene. The use of samples with various characteristics made it possible to assess more widely the ability of the greater wax moth larvae to wreak biodamage on polyethylene wastes

New approach to assessing the state of fish stocks on the example of bream

© 2020 Publishing House "O- Kratkoe". All rights reserved. This paper substantiates a new approach to the protection of fish resources, based on the transition from the concept of a calculated forecast of catches and quotas to a multilevel system for assessing the status of fish populations under conditions of slow flow. The main levels of the fish population monitoring system are considered. A new approach based an analysis of monitoring results of the main structural and functional population characteristics of fish, on data on the dynamics of the population size and its generations, changes in the age structure, growth rate, abundance of individuals with morphological anomalies. A new approach was tested on the example of a model species of bream (Abramis brama L.) in the Kuibyshev reservoir as a common inhabitant of different morpho-hydrological properties of reservoirs in Europe, belonging to the LC group according to the IUCN classification. An array of new scientific data has been obtained. Based on the calculation of natural mortality by approximating the population curve, taking into account the age composition of catches, it is shown that with a stable replenishment of the fishing herd, when high- and small-numbered generations enter the fishery, depending on the spawning conditions, bream stocks are not expected to be undermined. The results of the study can be used as a basis for assessing the state of fish populations, developing measures for the rational development of their reserves in conditions of unstable hydrological regime of reservoirs and weakening of control over fishing in the protection of fish resources