Modern commercial and biological characteristics of zander Sander lucioperca (L) of the Kuibyshev reservoir

Abstract

The article presents the research materials of pike perch r. Volga and the Kuibyshev reservoir and noted the changes that have occurred in its population. Prior to the creation of the reservoir in the conditions of the Middle Volga, male zander matured at the age of 5–6 years, females at 6–7 years. In the Kuibyshev reservoir, pike perch becomes sexually mature at the age of 4–5 years, and a small part of it matures at the age of three. In the reservoir, due to ecological plasticity and the ability to lay eggs in a wide temperature range, regardless of the level regime of the reservoir and the spawning substrate, a gradual increase in its biological indicators, abundance and reserves began to be noted. Improving the feeding conditions of zander in the reservoir contributed to earlier puberty, an increase in the absolute fecundity of fish and its abundance in the reservoir. This contributed to an increase in zander catches since 1974, which in 1985 reached a maximum of 517 tons (9,2% of the total fish catch in the reservoir). Sufficiently high catches of zander over the past 10–15 years indicate the stability of its stocks in the Kuibyshev reservoir, which currently tend to increase. The multi-age sizeweight composition of zander in the Kuibyshev reservoir is represented by both young and older individuals, and confirms that the population is in good condition.

The Low Ontogenetic Diet Diversity and Flexibility of the Pike-Perch, Sander lucioperca (Linnaeus, 1758) (Osteichthyes, Percidae): A Case Study

“…Apparently, one of the reasons for such a limited size range of pike-perch prey is that it has a limited gape, usually consuming prey no longer than 50% of its own length in central Europe [69][70][71][72], which was similar to our data.…”

“…In spite of the fact that a lot of studies of the fish of the region took place but did not deal in detail with the biology of pike-perch, this study is considered to have addressed a fundamental gap in the study of the biology of pike-perch in the region [72][73][74][75][76][77][78][79][80][81][82]. The majority of studies focused on the sizes and age structures, the nature of growth, and the dynamics of stocks, and we did not find anything that gives an effective picture of the biology of reproduction and food habits, in addition to the absence of a comparison between the river and the sea.…”

Changes in the value of the Volga-Sviyazhsky area for fish reproduction the largest reservoir in Europe - the Kuibyshev reservoir

“…The species composition of young-of-the-year fish in the study area is represented by 23 species, which confirms the reproduction of these species in the study area. Currently, 60 species of fish are found in this reservoir [4]. Not all fish species spawn in the coastal zone.…”

“…The Kuibyshev reservoir was created in 1955-1957, after the Volga River was blocked by a hydroelectric dam in the Zhiguli Mountains [1]. This reservoir has a multi-purpose use and is the largest not only in the European part of Russia, but also in Europe [2,3]. The reservoir has an important fishery value: 30 species are mastered by fishing, the main ones are such valuable ones as bream, pikeperch, carp, pike, european catfish, sterlet; less valuable fish are common kilka, roach, silver bream, blue bream, ziege, golden carp, ide, asp, bleak, white-eye bream, silver carp, burbot, perch, volga pikeperch and others.…”

“…The reservoir has an important fishery value: 30 species are mastered by fishing, the main ones are such valuable ones as bream, pikeperch, carp, pike, european catfish, sterlet; less valuable fish are common kilka, roach, silver bream, blue bream, ziege, golden carp, ide, asp, bleak, white-eye bream, silver carp, burbot, perch, volga pikeperch and others. Commercial stock of aquatic biological resources of this reservoir in 2000-2020 ranged from 29.2 to 37.2 thousand tons, and the catch -from 2.8 to 4.2 thousand tons [4]. In the reservoir the reproduction efficiency for many fish species is determined by the level and temperature regimes during the spawning season [5,6].…”