Igor Anatolievich Stolbunov

Electric fish barriers of various systems have long been successfully used to protect fish from entering water intake structures, especially under conditions that make it difficult to use other types of fish protection devices and structures. Strong electric fields created by electric fish barriers can affect the survival, physiological state and injury rate of juvenile and adult fish. At the same time, the sensitivity of fish to such impacts is largely determined by their size. In this regard, we have carried out a complex study to examine the biological safety of electric fields generated by the electronic programmable complex fish-protecting facility of electrical action (EPS IFPEI) on mass fish species from the coastal zone of the Caspian Sea and separate estuaries of its tributary rivers. Behavior and distribution of fish of different size groups (juveniles and adults) at different levels of electric impact from the fish barrier were tested. Survival and injury rates of fish at prolonged maximum voltage of electric fish barrier were evaluated. As a result of the experiments, the modes and parameters of the electric fish barrier (EPS IFPEI) effectively causing behavioral avoidance response in fish were established. Significant differences in survival of individuals from the intact (control) and electrically exposed (experimental) groups of fish were not revealed.

Information is provided on the distribution of a species alien to the ichthyofauna of Dagestan – the Amur Top-mouth gudgeon Pseudorasbora parva (Temminck et Schlegel, 1846) within the region. It was found that the species expanded its range in the region under consideration, in 2021 it was found in the rivers Manasozen (9 copies), Gamriozen (10 copies), Ulluchai (6 copies), Rubas (6 copies), Avar koisu (a tributary of the Sulak River, in the area of the Gotsatli HPP), as well as in L. Mooch. It is assumed that the widespread distribution of P. parva is associated with high ecological plasticity, migration activity of larvae and fry, their high survival rate, rapid growth and accelerated puberty. The presented morphological variability of the Amur Topmouth gudgeon population based on the study of 20 signs, including 5 meristic and 15 plastic, revealed a slight variability of morphological signs due to different habitat conditions in the region. The Amur Topmouth gudgeon is a natural focus of an infectious disease of the swim bladder, dangerous for autochthonous ichthyofauna and aquaculture facilities, and a food competitor and consumer of caviar and larvae of autochthonous fish. With high numbers and prolonged starvation, P. parva can be a serious competitor for juvenile carp and variegated carp, and exhibit a predatory reaction towards commensurate juveniles of commercially valuable fish species. To control the number of this alien in the region, it is advisable to use native predators – perch Perca fluviatilis (Linnaeus, 1758), pike Esox lucius (Linnaeus, 1758) and walleye Sander lucioperca (Linnaeus, 1758).

Long-term data (1996–1999 and 2008–2014) are presented on the species composition, density of aggregations, and distribution of juvenile fish in various types of shallow coastal areas of the Rybinsk Reservoir and the mouths of its tributaries. The earliest information (1950s–1980s) on the formation of the fish population in the reservoir as a result of the adaptation of individual species to changed living conditions is considered. The characteristic features of the distribution of juvenile fish in the tributaries of the reservoir are shown: in the coastal zone of the mouth area and areas of bordering systems. Patterns of the distribution of juvenile fish in years of different water contents were revealed.

Fish in the Volga-Kama River System (the largest river system in Europe) are important as a crucial food source for local populations; fish have the highest trophic level among hydrobionts. The purpose of this research is to describe the diversity of non-indigenous and native fish in the Volga and Kama Rivers, in the European part of Russia. This dataset encompasses data from June 2001 to September 2021 and comprises 1888 records (36,376 individual observations) for littoral and pelagic habitats from 143 sampling sites, representing 52 species from 42 genera in 22 families. The dataset has a Darwin Core standard format and has been fully released in the Global Biodiversity Information Facility (GBIF) under CC-BY 4.0 International license. The data are validated with several international databases such as FishBase, Eschmeyer’s Catalog of Fishes, the Barcode of Life Data System, and the SAS.Planet geoinformations system. Newly established populations have been found for several species belonging to the following Actinopteri families: Alosidae, Anguillidae, Cichlidae, Ehiravidae, Gobiidae, Odontobutidae, Syngnathidae, and Xenocyprididae. Therefore, this dataset can be used in the particular taxon species distribution analysis, which are especially important for non-indigenous species.

Aim. Experimental assessment of the impact of electric fields generated by the Electronic Programmable Complex Fish‐protecting Facility on the Electric Principle (EP EPRCFF) on the most common fish species of the Black Sea.Material and Methods. Experimental studies were conducted at the marine test site in the Quarantine Bay of the Black Sea (May‐September, 2021). The following were investigated on larvae, juvenile and adult fish of common species: behavioral responses to electrical fields, survival during and after exposure to the electric field of the fish barrier and the effects of electricity on the reproductive system and biochemical parameters of fish.Results. The features of behavior and distribution of larvae, juvenile and adult fish in the electric field of a fish barrier in modes of different intensity have been analysed. Survival estimation of fish during and after electric influence of the fish barrier has been carried out. The data on the influence of the electric screen on the reproductive system of fish and the biochemical characteristics of their internal organs were analysed.Conclusion. The larvae of fish exhibit a clear “first reaction” to the impact of the electric fish screen. However, there is no avoidance effect (i.e. escape of fish larvae from the area of the working electrode system). The juveniles actively move from the operation zone of the fish‐protective device, avoiding the influence of the electric field. The maximum distance from the electrode system EPRCFF was recorded in adult fish. Significant differences were not revealed in the direct assessment of the survival rate of control and experimental groups of individuals of different species of marine fish after exposure to the electric fish barrier. Some differences on the reproductive system of the fish species studied in the structure of gonads and reactivity of cells were noted under the influence of the electric barrier. The biochemical status of the internal organs under electrical action differed in various species of marine fish.

The food spectrum and trophic and length–weight characteristics of an invasive species, South American suckermouth armored catfishes Pterygoplichthys spp. (Loricariidae), from lotic and lentic inland waters of Vietnam have been studied. It is found that the diet of suckermouth armored catfishes consists of plant and animal food, as well as organic detritus. According to the predominant type and pattern of feeding, suckermouth armored catfishes can be classified as detritivore gatherers (janitor). Some specimens of catfish with a high consumption of animal food have been identified. It is noted that invasive suckermouth armored catfishes can be a significant food competitor for aboriginal fish species; detritivores; and, possibly, benthophages in the lotic and lentic inland waters of Vietnam.

An Erratum to this paper has been published: https://doi.org/10.1134/S1995082921100011

The distribution of alien species of suckermouth armored catfishes (Loricariidae) in the water bodies and water streams of southern Vietnam has been studied. The taxonomic composition of suckermouth armored catfish is determined based on the data of morphological and molecular genetic analysis. Two species of armored catfishes, Pterygoplichthys pardalis and P. disjunctivus, as well as their interspecific hybrid (P. pardalis × P. disjunctivus), are found in the studied reservoirs and watercourses of southern Vietnam. Nowadays, the suckermouth armored catfish Pterygoplichthys spp. inhabits the basins of almost all major river systems of southern Vietnam.

Presently, invasive fish species become dominant in some freshwater waterbodies and watercourses of Central and South Vietnam in terms of abundance, successfully competing with native species for ecological niches and environmental resources. This can ultimately reduce the diversity of native fish communities and cause their further transformation. Loricariids are considered the main group of invasive fish species being a serious threat to tropical and subtropical freshwater ecosystems. In this regard, the distribution and morphology of suckermouth-armored catfishes (Pterygoplichthys spp.) in different habitats of Central and South Vietnam were studied. A total of 54 reservoirs belonging to the basins of 15 large and small rivers were surveyed. Specimens were examined for 7 meristic and 34 plastic characters. The osteological analysis of the axial skeleton of fish conducted using radiography. Morphological differences and a number of developmental anomalies of morphology were found in different armored catfish populations from Vietnamese waters. It is noted that deliberate or accidental introduction of suckermouth-armored catfishes and their further spread can have negative consequences for the biodiversity of Vietnam’s aquatic ecosystems.