Features of catching white bream (Blicca bjoerkna (Linnaeus, 1758)) from Kуiv reservoir (a review)

Purpose.To analyze the array of special literature and summarize the information obtained on the features of the white bream (Blicca bjoerkna (Linnaeus, 1758)) and its commercial catch from the Kуiv reservoir. Consider the basic principles of its forecasting, based on the current ecological state of this reservoir, which is of strategic importance for Ukraine. Findings. An overview of modern scientific publications devoted to the peculiarities of the commercial catch of white bream from the Kуiv reservoir, its forecasting and the prospects for using this species in fisheries is presented. The literature data on the specifics of industrial fishing in the Kуiv reservoir are summarized based on the ecological characteristics of this reservoir. The main factors influencing the adaptation of white bream populations to their commercial exploitation are described. The general directions of the impact of anthropogenic pressure on them and their consequences are considered. The prospects of using white bream as an economically valuable species are shown under the condition of rational industrial fishing in the Kуiv reservoir. Practical Value. The review can be useful for scientists, applicants, students, government authorities and private entrepreneurs involved in the process of research and commercial harvesting of living aquatic resources in reservoirs, namely in Kуiv reservoir. Keywords: white bream (Blicca bjoerkna Linnaeus, 1758), Kуiv reservoir, industrial fishing, ichthyofauna.

White bream (Blicca bjoerkna (Linnaeus, 1758)). Thematic bibliography

Purpose. Forming a thematic bibliographic list of publications on the morphological, ecological, physiological and biochemical characteristics of white bream (Blicca bjoerkna L.), as well as the state of its stocks in natural reservoirs. Methodology. Complete and selective methods were applied in the process of the systematic search. The bibliographic core have been formed with the publications exclusively in Ukrainian and Russian from the fund of scientific library of the Institute of Fisheries NAAS of Ukraine. Findings. A thematic list of publications with a total quantity of 62 sources covering the time interval from 1960 to 2020, and highlighting ecological characteristics of a member of Cyprinidae family, the white bream, as well as considering the state of its populations has been composed. The literary sources were arranged in alphabetical order by author or title, and described according to DSTU 8302:2015 “Information and documentation. Bibliographic reference. General principles and rules of composition”, with the amendments (code UKND 01.140.40), as well as in accordance with the requirements of APA style — international standard of references. Practical value. The list may be useful for scientists, practitioners, students, whose area of interests includes the study of physiological, biochemical, ecological and other characteristics of Cyprinids, in particular white bream (Blicca bjoerkna L.). Key words: white bream, spawning, morphological, physiological and biochemical characteristics, fishing.

Modelling of white bream (Blicca bjoerkna (Linnaeus, 1758)) commercial catches by different parameters of fishing gillnets in Kyiv Reservoir

Purpose. To analyze the existing experience in quantitative and qualitative modelling of commercial fish harvesting and to develop the methodological approaches in determining the optimal catch parameters for gillnets. Methodology. An adjusted annual commercial mortality rate was used to determine the catches composition in gillnets with different mesh sizes. Findings. The proposed model was developed within the framework of the generally accepted concept of population dynamics and biomass as a result of mortality and weight growth. It showed the dependence of the size-age structure and total weight of the catch on the mesh size of the grids. Originality of the work was caused by using the mathematical model that can ensure sustainable use of nature based on the optimal parameters of shutter grids on the possibility of their effective removal of certain age groups of white bream for the first time. Practical Value: calculations performed according to this model for the white bream of the Kyiv Reservoir showed that it is optimal to use grids with a mesh step of 40-50 mm, which allow to obtain the maximum catch per unit of replenishment and ensure high population fertility. Keywords: white bream (Blicca bjoerkna Linnaeus, 1758), Kyiv reservoir, commercial catches, modelling of catch.

NATURAL AND SOCIAL FACTORS OF OPISTORCHOSIS CIRCULATION IN WEST KAZAKHSTAN REGION

The formation and course of epidemic and epizootic processes of opisthorchiasis is influenced by natural-ecological and socio-economic factors. Geographical position of the Ural River basin, the proximity of the Volga focus, species diversity and abundance of commercial species of cyprinids, ecological conditions in the Ural basin, in floodplain water bodies and in small rivers of West Kazakhstan region, connected with the Ural River, the dietary habits of people, intensive migration of population create optimal conditions for the functioning of parasitic system of opisthorchiasis and contribute to the spread of this invasion among the population of the Ural region.The risk of infection with opisthorchiasis at the natural and social levels remains high. The territory of West Kazakhstan region has the following natural and ecological conditions: it is confined to the Ural-Caspian lowland. Surface waters of West Kazakhstan region are represented by rivers, lakes and reservoirs. In the Ural River and its basin, there are many mollusks Bithynia leachi and fish species, among which there are potential carriers of opisthorchian metacercariae – bream, ide, dace, redfin, tench, wild carp, carp, white bream, roach, asp, prussian and crucian carp, chub, minnow, sabre fish, blue bream. In the region, the incidence of opisthorchiasis in people is annually recorded. A significant part of the infected population lives in settlements located along the banks of the Ural River and its floodplain reservoirs.

Age and growth of two bream species in the Tudakul reservoir of Uzbekistan

The study was carried out in 2014-2018 at the Tudakul reservoir, Uzbekistan. Samples included 278 European bream (Abramis brama), and 83 Amur white bream (Parabramis pekinensis). The age, total length and weight of the fish varied from 1 to 5 years, from 14 to 50 cm, from 30 to 1,405 g for the European bream and from 1 to 6 years, from 24 to 53.5 cm and 105 – 2,138 g for the white Amur bream and European bream, respectively. The relationship between total length (TL) and weight (W) is described by the equation W = 0.005 * TL3.2555 (r = 0.98) for European bream and W = 0.005 * TL3.201 (r = 0.96) for white Amur bream. Recovered average growth rate of European bream: TL1 - 13.5 cm; TL2 - 28.1 cm, TL3 - 37.95 cm, TL4 - 42.6 cm, TL5 - 48.6 cm.The average height of the Amur white bream: TL1 - 12.6 cm, TL2 - 23.3 cm, TL3 - 31.5 cm, TL4 - 37.9 cm, TL5 - 41.7 cm, TL6 - 44.2 cm. Lee’s phenomenon did not appear. All yearling fish were juvenile. In 2-year-old fish of both sexes of both species, the gonads were at stage II. Males and females of both species reached their first maturity at 3-4 years of age, when the total body length of the European bream was 30–32 cm, and the Amur white bream was 34–35 cm.

BIOLOGICAL CHARACTERISTICS OF WHITE BREAM BLICCA BJOERKNA (LINNEUS, 1758) IN THE UPPER PART OF THE VOLZHSKY SECTION OF THE KUYBYSHEV WATER RESERVOIR

The article describes the state of the White bream in the upper reaches of the Kuibyshev reservoir in the period from 2009 to 2019.

The epidemiological significance of parasites of fishes in the Volga-Caspian fishery subdistrict (Astrakhan region)

Introduction. The epidemiological situation of parasitic diseases among the population of the Volga-Caspian fishery subdistrict within the Astrakhan region continues to be stressful. To cancel or prolong the restrictions on biohelminthoses in the region, it is necessary to conduct regular studies on the parasitic purity of fish and fish raw materials. Material and methods. In accordance with methods generally accepted in parasitology, in the period of 2013-2017, 7,671 mature specimens of thirteen species of fish of five families (carps, pikes, sheatfishes, perches, herrings) were examined. Results. In the parasitic fauna of all types of hydrobionts examined there were sanitary-significant parasites, represented by eight types of systematic groups: nematodes (Anisakis schupakovi, Contracaecum bidentat, Estrongylides excisus), trematodes (Apophallus muehlingi, Rossicotr.ema donutses), acanthocephalans (Corynosoma strumosum). The dominant group in prevalence in the population of the Volga fish were roundworms, small - acanthocephalus. The maximum quantitative indices were characterized by trematodes, the number of which in the single fish amounted to thousands. Discussion. The level of infestation of pike, catfish, bream, carp, pike-perch, perch, white bream, rud, roach, Caspian roach, sichel, Caspian anadromous shad, blue bream, parasites dangerous to humans has remained relatively stable for a number of years. The majority of fish in the eastern part of the delta (with respect to the western part) have a higher percentage of infected individuals, and therefore, aquatic animals caught in the first specified area should be subjected to more thorough veterinary examination when preparing it for sale to the population. Conclusion. The data on the annual invasions of fish and people (along with other warm-blooded animals) with epidemiologically significant parasites indicate the active functioning of natural foci of apophallosis, rosicotremosis, opisthorchiasis, pevdoamphistomosis, anizakiosis, contratsekoleza, eustrongilidosis, and corynozomosis in the Volga delta. For the prevention of biohelminthoses, it is necessary, in addition to state control (ensuring proper product quality), to establish a direct informational notification of the population in order to clarify the importance of the issue of parasitic invasions transmitted through fish.

The epidemiological significance of parasites of fishes in the Volga-Caspian fishery subdistrict (Astrakhan region)

Introduction. The epidemiological situation of parasitic diseases among the population of the Volga-Caspian fishery subdistrict within the Astrakhan region continues to be stressful. To cancel or prolong the restrictions on biohelminthoses in the region, it is necessary to conduct regular studies on the parasitic purity of fish and fish raw materials. Material and methods. In accordance with methods generally accepted in parasitology, in the period of 2013-2017, 7,671 mature specimens of thirteen species of fish of five families (carps, pikes, sheatfishes, perches, herrings) were examined. Results. In the parasitic fauna of all types of hydrobionts examined there were sanitary-significant parasites, represented by eight types of systematic groups: nematodes (Anisakis schupakovi, Contracaecum bidentat, Estrongylides excisus), trematodes (Apophallus muehlingi, Rossicotr.ema donutses), acanthocephalans (Corynosoma strumosum). The dominant group in prevalence in the population of the Volga fish were roundworms, small - acanthocephalus. The maximum quantitative indices were characterized by trematodes, the number of which in the single fish amounted to thousands. Discussion. The level of infestation of pike, catfish, bream, carp, pike-perch, perch, white bream, rud, roach, Caspian roach, sichel, Caspian anadromous shad, blue bream, parasites dangerous to humans has remained relatively stable for a number of years. The majority of fish in the eastern part of the delta (with respect to the western part) have a higher percentage of infected individuals, and therefore, aquatic animals caught in the first specified area should be subjected to more thorough veterinary examination when preparing it for sale to the population. Conclusion. The data on the annual invasions of fish and people (along with other warm-blooded animals) with epidemiologically significant parasites indicate the active functioning of natural foci of apophallosis, rosicotremosis, opisthorchiasis, pevdoamphistomosis, anizakiosis, contratsekoleza, eustrongilidosis, and corynozomosis in the Volga delta. For the prevention of biohelminthoses, it is necessary, in addition to state control (ensuring proper product quality), to establish a direct informational notification of the population in order to clarify the importance of the issue of parasitic invasions transmitted through fish.

Responses of the fish community in a eutrophicated lake to long-term food web management assessed by multiple sampling methods

Fish community responses to long-term mass removal of planktivorous fish from eutrophicated Lake Tuusulanjärvi were examined during 1996–2018 by gill net test fishing, hydroacoustics with simultaneous trawling, virtual population analysis (VPA) and fish growth measurements. The gillnet catches of white bream and roach increased first while bream and bleak decreased but recovered in the early 2000s. Perch and pikeperch increased but ruffe decreased and remained low. According to hydroacoustics, pelagic fish biomass decreased. Smelt was the most abundant species at the beginning and the end of the monitoring period but bream dominated the fish biomass in most years. VPA calculations indicated a five- and threefold increase in the biomass of bream and white bream, respectively, during 2005–2011. Significant increases appeared in the growth of perch, bream and roach. Overall, the responses in the fish community structure and fish abundance to the food web management were slight and mostly masked by changes in reproduction and growth of fish and annual variability in environmental conditions such as temperature and water turbidity. Gillnet test fishing and echo sounding complemented each other well in monitoring the effects of management fishing. Where bream is one of the dominant species VPA is also recommended.