On expansion of goby fishes (Neogobius and Proterorhinus) in shallow shore areas of Kuybyshev Reservoir, Russia

Abstract

101Kuybyshev Reservoir, the largest reconstructed water body of the basin of the Volga and Europe, is characterized by a rather complex morphology and heterogeneity of conditions of different parts. This cir cumstance manifests itself not only under different hydrological conditions of individual areas but also in the specifics of the anthropogenic impact (Kuiby shevskoe vodokhranilishche, 2008). With respect to ichthyofauna, it was shown that heterogeneity becomes a cause of different contributions of isolated parts of the water body to reproduction of the fish stock (Kuznetsov, 1978;Kuznetsov and Galanin, 2000). The late 1980s were marked by an increase in fish invasions in the Volga and Don basins that assumed a pattern of mass explosive expansion espe cially for representatives of the family Gobiidae (Slyn'ko et al., 2010). One should expect that the rate of bioinvasion processes in some areas of the reservoir will be different. The purpose of the paper is, on the basis of long term observations, to generalize the fact of catches of gobies of the genera Neogobius and Prot erorhinus dwelling near the shore of the Volga stretch of the Kuybyshev Reservoir and compare them with available data on other areas of the reservoir. MATERIALS AND METHODSThe material for the work comprised data on regis tration of gobies in the course of annual observations of the state of juvenile fish near the shore, results of control catches with gill nets (mesh of 16-65 mm), and episodic evidence on catches of gobies with hook and line gear for the period of 1993-2009 in the upper part of the Volga stretch of the Kuybyshev Reservoir. Observations of the state of juvenile fish near the shore were performed in July and September using fry drag seine (length of 12 m, mesh in the wings of 5 mm, mesh in the seine bag of 2.5 mm) and gas drag seines (length of 3 m, gas no. 10) at 18 stations of the littoral at two sections: in the lower reaches of Sviyaga Bay and in the Volga Sviyaga area. Besides this, data on other areas of the Kuybyshev Reservoir were used in the paper. For analysis, similar materials obtained in the course of work in different areas of the Kama stretch in the period of 2006-2007 were also used. The numbers of fish were assessed in specimens per one fishing effort. RESULTS AND DISCUSSIONAt the present stage, near the shore of the upper part of the Volga stretch of the Kuybyshev Reservoir, there are two representatives of the genus Neogobius and one of the genus Proterorhinus. Data of observa tions for the period of 1993-1999 reflect a complete absence of gobies in the composition of catches of juveniles in the littoral and gill nets. Round goby Neogobius melanostomus (Pallas, 1814) was the first to be found in this area (Fig. 1). The first three young of the current year gobies were caught in 2000. Near the shore, round goby is common on rocky grounds and also occurs less frequently in other habitats. Since rocky grounds in the littoral of the considered areas are not widespread, the total numbers of this species in rec...

Alien Species of Fish in the Littoral of Volga and Kama Reservoirs (Results of Complex Expeditions of IBIW RAS in 2005-2017)

“…The donor region of this fish is probably located in the Lower Volga and its delta as well as in the brackish area of the Caspian Sea. According to literature, Caspian bighead goby penetrated into the Volgograd reservoir in 1970's (Gavlena, 1977), a decade later -Saratov reservoir (Kozlovskaya, 1997), its expansion in the Kuybyshev reservoir continues [Galanin, 2012]. It is locally present in the Cheboksary reservoir, single specimens were found in the Gorky reservoir (Klevakin at al., 2005).…”

“…nasalis [Sorokin et al, 2011], Pr. marmoratus sensu lato [Galanin, 2012], Pr. semilunaris [Slynko et al, 2013].…”

Species composition of ichthyofauna of the Kuibyshev reservoir

“…It prefers coastal thicket biotopes, enters tributaries, and even relatively rapid rivers. It is characterized by local distribution and is one of the most short cycle species of the family Gobiidae (Galanin and Shakirova, 2006;Galanin, 2012). The age of fish studied by us in the reservoir did not exceed 1+.…”

“…54 No. 8 2014 in catches and the absence of juveniles in upper stretches indicate that the process of naturalization of the big headed goby at this site of the reservoir contin ues (Galanin, 2012). Big headed goby prefers stony and sandy biotopes of the coastal zone.…”

“…Caspian big headed goby was caught for the first time in the low stretches of the Kuibyshev reservoir (Volga stretch) in autumn 2007 (Aleev and Semenov, 2003;Galanin, 2012). A small number of individuals Vol.…”