Long-Term Changes in the Importance of Aboriginal and Invasive Fish Species for Feeding of Predatory Fish of the Rybinsk Reservoir

2018 ◽  
Vol 58 (5) ◽  
pp. 601-616 ◽  
Author(s):  
Yu. V. Gerasimov ◽  
M. N. Ivanova ◽  
A. N. Svirskaya
Author(s):  
Andrey Dmitrievich Bykov ◽  
Svetlana Yuryevna Brazhnik

The article considers the issue of assessing the long-term results of work on fisheries reclamation in inland waters of fisheries significance in Russia, carried out by the branches of the Federal State Budgetary Institution “Glavrybvod” on the state task in terms of their effectiveness. The relationship between dredging and clearing of watercourse beds and the dynamics of the number of producers of semi-navigable and non-aquatic fish in these rivers during spawning migrations has not been established. With long-term mowing of wetland vegetation in the shallow waters of reservoirs, deltas of large rivers and estuaries, there is no increase in their commercial fish productivity. A number of examples show the opposite effect of this type of work, which leads to a local deterioration of the ecological state of these reservoirs. At the same time, the repeatedly proven method of combating higher aquatic vegetation in the reservoirs of the south of Russia in low water conditions as biomelioration, based on the introduction of fish, consumers of autotrophic products by regional branches of the Federal State Budgetary Institution “Glavrybvod” is practically not used. When installing artificial spawning grounds in the littoral zone of reservoirs, regular ichthyological monitoring of the effectiveness of spawning on them is not carried out. There are no reliable data confirming the significant positive impact of artificial spawning grounds on the population dynamics of commercial fish species of the limnophilic ecological group under conditions of significant spring water level depletion in Russian reservoirs. When catching predatory and low-value fish species in water bodies, legal obstacles arise due to the fact that the volume of seizure of predatory fish includes commercial objects for which the ODE is established annually and their catch is already carried out according to industrial quotas.


2021 ◽  
Vol 29 (1) ◽  
pp. 10-16
Author(s):  
N. M. Mineeva

Long-term observations are necessary to analyze and predict changes occurring in biological communities under global and regional climatic changes. The data on seasonal and long-term dynamics of chlorophyll in plankton of the Rybinsk Reservoir (Upper Volga, Russia) obtained in May – October 2009–2019 at six standard stations using the fluorescence method are presented. In the years with contrasting hydroclimatic conditions and water regime, the chlorophyll content varied from 1–3 to >100 μg/L. The significant variability of mean seasonal values (7.9 ± 0.5 μg/L in 2009 to 27.6 ± 1.7 μg/L in 2013 with variation coefficients of 52–134%) indicates the low resistance of the community. The total chlorophyll content is associated with the development of three main phytoplankton divisions i.e., diatoms, cyanoprokaryots, and green algae. The trophic status of the reservoir was characterized as mesotrophic in 2009 and 2017, eutrophic in 2011–2014, and moderately eutrophic in other years. In the long-term seasonal cycle of phytoplankton, there are five periods with stable temperature conditions and transparency, but variable chlorophyll content. A moderate positive relationship was found between the seasonal dynamics of chlorophyll and water temperature, but a moderate negative relationship with transparency. The priority factors regulating the long-term dynamics of chlorophyll include the NAO indices, Wolf numbers, temperature, and underwater light conditions, as well as the inflow volume and water level. Water regime limits the development of phytoplankton.


2008 ◽  
Vol 21 (3) ◽  
pp. 307-316 ◽  
Author(s):  
Pascal Le Floc'h ◽  
Jean-Charles Poulard ◽  
Olivier Thébaud ◽  
Fabian Blanchard ◽  
Julien Bihel ◽  
...  

Author(s):  
Lyudmila G. Korneva ◽  
Vera V. Solovyova ◽  
Sergey I. Sidelev ◽  
Ekaterina N. Chernova ◽  
Yana V. Russkich

A comparative of the species composition and ecological-geographical characteristics of cyanobacteria plankton of 13 reservoirs of the Volga-Kama cascade and the Don (Sheksna, Ivankovo, Uglich, Rybinsk, Gorky, Cheboksary, Kuibyshev, Saratov, Volgograd, Kama, Votkinsk, Nizhnekamsk and Tsimlyansk reservoirs) is analysed. An assessment of the change in the distribution of cyanobacteria biomass in a latitudinal gradient along the Volga cascade is presented. The seasonal and long-term (1954–2016) dynamics of the abundance, biomass and the ratio of functional groups of cyanobacteria in the Rybinsk Reservoir, the second largest in the cascade of Volga reservoirs, are analyzed. A positive long-term trend of abundance and diversity of cyanobacteria and the leveling of their biomass between reservoirs along a cascade in recent years has been established. An increase in the abundance and diversity of nonheterocystous species was established in the direction from the Upper to the Lower Volga and during the long-term succession of phytoplankton of the Rybinsk Reservoir. This is associated with an increase of water mineralization. Based on current research in the 2010s of the Volga, Kama and Don cascade reservoirs, 14 variants of microcystin structures were identified, the diversity of which depended on the composition of the producing species. Using PCR analysis, the main producers of microcystins (Microcystis and Dolichospermum) were identified. Cyanobacteria Cuspidothrix issatschenkoi and/or Raphidiopsis mediterranea have been identified as possible producers of neurotoxic anatoxin-a in the Tsimlyansk Reservoir. It was shown that water temperature and nitrogen were the greatest importance for development of microcystin-producing species of cyanobacteria.


2021 ◽  
Vol 14 (6) ◽  
pp. 679-690
Author(s):  
N. M. Mineeva

Abstract On the basis of field observations in 2009–2019, the seasonal and long-term dynamics of chlorophyll at six standard stations of the Rybinsk Reservoir is considered. The fluorescence method is used to determine chlorophyll. The average chlorophyll content at stations varies from the minimum 3.5–10.8 to the maximum 16.9–40.5 μg/L in different years and from 12.0 at station 5 (Sredny Dvor) up to 21.6 μg/L at station 2 (Mologa) on average for the entire period. The seasonal dynamics of chlorophyll is characterized by spring; summer; and, in some years, autumn maxima. With the same type of seasonal dynamics, the change in chlorophyll at the stations is to varying degrees coupled in the years of observation and is most often correlated in neighboring areas. Significant differences in the amount of chlorophyll at the stations are observed during surveys carried out within one day and are determined by the complex hydrological structure of the reservoir; active dynamic processes; and, in the spring, by the thermal regime. The presence of stable large circulation zones smoothes out the spatial differences of chlorophyll, the average seasonal concentrations of which do not differ significantly at all six stations in years with an average water level, and at four stations of the Main Reach in extremely high-water years. A close correlation in long-term dynamics is revealed for the average chlorophyll concentrations for the growing season at six stations, as well as at each station and the reservoir as a whole. The results of the work confirm the reliability of the data obtained for assessing the ecological state of the Rybinsk Reservoir.


2020 ◽  
Vol 3 (3) ◽  
Author(s):  
Roza A. Lozhkina ◽  
Irina I. Tomilina

Long-term dynamics of the aquatic toxicity was studied in the Rybinsk Reservoir. According to the biotesting, the Volga and Sheksna reaches were the most polluted areas, which were exposed to household and industrial wastewater, as well as to the diffuse runoff from agricultural land and major highways. The relationships between the parameters of toxicity and indicators of the chemical composition of water were analyzed.


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