THE ICHTHYOFAUNA OF THE LAKES OF THE SURA RIVER VALLEY IN PENZA REGION BY THE EXAMPLE OF LAKE PECHARKA

Abstract

Background. The lakes that are in the region play an important role in the life of river ecosystems. They have a positive impact on the quality of water entering the river channel, serve as the main suppliers of phyto- and zooplankton for the inhabitants of flowing river water and a place of spawning and foraging of many species of fish living in the river. In recent decades, there has been a process of active degradation of the ecosystems of these reservoirs. Therefore, the identification of poorly disturbed ecosystems of lakes-stars with well-preserved ichthyofaun and their inclusion in the specially protected natural areas (PLA) in the status of natural monuments of regional importance is an actual scientific task. One of these bodies of water is Lake Pecharka, located in the Sura river in the Nikolsky district of the Penza region. In this regard, the purpose of this work was to study the lake’s ichthyofauna, its size and develop recommendations on the feasibility of including the reservoir in the protected area in the status of a natural monument of regional importance. Materials and methods. Ichthyological studies on Lake Pechaka were carried out in August – October 2019 in three areas of the reservoir: the upper shallow reach, in the shallow waters of the left and right coast of the central reach. We analyzed fish from fixed nets and other fishing gear, conducted research with an underwater video camera. Biological analysis of fish, expert assessment of the number and ichthyomass of fish were carried out according to conventional methods. We have also conducted a comparative characteristic with the results of studies on another lake of the Sura River basin – the reference lake. Sanderka, included in the PLO. Results. As a result of research on the Lake Pecharka has identified 15 species of fish. The most widespread species of them is the roach Rutilus rutilus, a number of other species – perch Perca fluviatilis, rudd Scardinius erytrophthalmus, bream Abramis brama, crucian carp Carassius auratus and pike Esox lucius can be attributed to common fish species, other fish are few in number. Fish of the lake belong to 5 fauna complexes: boreal plain, tertiary plain freshwater, pontocaspian freshwater, arctic freshwater, boreal foothill. The lake’s ichthyofauna is characterized by a low growth rate of fish. The reasons for the total predominance of females among the fish analyzed require special research. The total number of commercial fish from the age of 2 years and older is estimated at 7000 ex/ha, ichthyomassa – 164 kg/ha. Conclusions. In the Lake Pecharka has been preserved rich historically formed ichthyofauna, which testifies to the uniqueness of this body of water in relation to species diversity. The high biodiversity of the lake is associated with both the permanence of habitats in the reservoir, and the period of spring flood, when the reservoir can connect to the river Sura, which is the result of the species “enrichment” of ichthyofauna. Therefore, there are species characteristic of both flowing reservoirs, and closed, without currents. The Lake Pecharka furnace has unique conditions for the preservation of biodiversity and maintenance of a high number of fish – phytophiles, bentofags, predators. Currently, a rich limnophilic complex is a very rare phenomenon for the river Sura’ river-covered reservoirs. In this regard, it is necessary to make it into the specially protected natural areas of the Penza region in the status of a natural monument of regional importance.

Keywords

• floodplain lakes
• ichthyofauna
• abundance
• ichthyomass
• faunal complex
• natural monument