Gorčin Cvijanović

Institute for Multidisciplinary Research, University of Belgrade · Department of Natural Resources and Environmental Sciences

European rivers are obstructed by more than one million barriers that have resulted in excessive loss of river continuity (Belletti et al. 2020). On the main course of the Danube River there are 83 longitudinal continuity interruptions, out of which 65 dams are used for hydropower (ICPDR 2022a). The Iron Gate Hydropower and Navigation System is one...

Introduction River infrastructures, such as hydropower plants Iron Gate I (IG; rkm 943) and II (rkm 863) represent major obstructions to fish migration in the Danube River. Knowledge about fish behaviour and movements in the vicinity of major river structures is required to build effective fish passages to protect migratory fish species, with acous...

bstract: Water temperature plays an important role in the fish life cycle, and have a direct impact over fish species movement behavior, migration, feeding and reproduction. The impact might be different between the rivers because of hydro morphological factors that are specific for each watercourse (sediments, water conductivity, turbidity, total...

The dam's construction without fish passes had a major impact, obstructing migratory fish populations from moving between different parts of the river systems and utilize they key habitats. Fish species and fish populations are depending on long migrations are most seriously affected by river fragmentation. Building well-functioning fish passage sy...

In recent decades, the Amur sleeper (Perccottus glenii) is one of the most impressive east-to-west invaders of European inland waters, but there are insufficient data on its biology in the countries it has entered. Specimens of two sets of samples from November 2015 (n=25) and October 2016 (n=39) were caught in the Danube River channel near Veliko...

The Danube River basin represents a hotspot for the European freshwater diversity. The Danube in Serbia is characterized by a significant level of fish diversity, as well as by economically important fish resources. However, the Danube fish fauna is facing a number of adverse anthropogenic impacts, such as unsustainable fishery, habitat loss and fr...

Climate change is expected to strongly affect freshwater fish communities. Combined with other anthropogenic drivers, the impacts may alter species spatio‐temporal distributions, and contribute to population declines and local extinctions. To provide timely management and conservation of fishes, it is relevant to identify species that will be most...

During the last decades in the freshwater system in Serbia 32 allochthonous fish species appeared, and they can be divided into five groups according to their region of origin: Asian, Ponto-Caspian, North American, South American, and Europe without Ponto-Caspian region. The Asian and Ponto-Caspian species are the most numerous. In the first group...

Climate change is expected to strongly affect freshwater fish communities. Combined with other anthropogenic impacts, the impacts will alter species distributions and contribute to population declines and local extinctions. To provide timely management and conservation of fishes, it is relevant to identify species that will be most impacted by clim...

Species diversity is related to the function of ecological systems and it helps to understand the effects and mechanisms of environmental disturbances. Rise of concern regarding the water quality and water availability lead to a development of effective ecological tools capable of detecting the extent of anthropogenic impact. The significance of fi...

The paddlefish (Polyodon spathula) was first introduced to Europe in 1974, mainly due to its potential for rearing in natural polyculture ponds and large temperate reservoirs. The information on the history of paddlefish aquaculture efforts in Europe is scarce, as well as data on current paddlefish aquaculture status and trends. In addition, there...

Sterlet populations have experienced a decline during the 20th century throughout its range, mainly due to poorly regulated fisheries, pollution, habitat fragmentation and habitat loss. They still represent a species of significant economic importance in the Middle and Lower Danube, so the present study was designed to investigate genetic diversity...

Amur sleeper (Perccottus glenii) represents invasive species to European waters, where it can have negative impact on eggs and larvae of autochthonic fish species, as well as aquatic macroinvertebrate and larval amphibians. Our research includes 85 specimens from channel near Veliko Gradište (Serbia), during 2015-2016 survey. Body length of specime...

Fishery in the Danube River basin has been characterised over the past century by increasing fishing levels, illegal fishing practices and poor regulations. However, there is a remarkable lack of available information on the actual status of fish stocks, as well as on the trends and sustainability of fisheries, which poses a problem for the develop...

Poor regulated fishery, pollution, fragmentation and loss of habitat are most important factors influencing decline of sterlet population worldwide. In Middle and Lower Danube region, this species still have significant economic importance since wilde populations are commercially exploited, while Upper Danube populations are dependent on stocking e...

While the historical sturgeon catch in Serbia encompassed mainly four species (beluga sturgeon - Huso huso, Russian sturgeon - Acipenser gueldenstaedtii, stellate sturgeon - Acipenser stellatus, and sterlet - A. ruthenus) most of the research, especially since 1956, has been conducted on sterlet. More detailed studies started in 2001 and comprised...

Invasive species have the ability to modify their life-history traits in newly colonized areas, with positive shifts in specific life history traits under favourable environmental conditions. If such positive changes in their life history result in a comparably larger population growth rate, it may give them a competitive edge over native species,...

The Tens Rule, as well as the last stage described therein, i.e., the proportion of established species that becomes pests, is frequently perceived by the scientific community to indicate that introduced established species have little impact on communities. This belief is dangerous because it strengthens the perspective of the general public and d...

The aim of this paper was to use geometric morphometry as a helpful tool to clarify the overlap between meristic characters (such as the number of anal fin rays) of different fish identification keys employed for the two sister species, Ameiurus melas and Ameiurus nebulosus. Geometric morphometry included shape analysis of 15 landmarks on 432 speci...

Fish populations worldwide have experienced severe decline, and some of the species are facing a serious threat of extinction. Population simulations are currently the most promising approach for the assessment of extinction risk and the evaluation of alternative management measures. The population viability analysis (PVA) represents a method that...

Sturgeon populations in the Danube River have experienced severe decline during the last several decades, mostly due to the poorly regulated fishery, river fragmentation and water pollution. This study focuses on gaining better understanding of sturgeon life history primarily by addressing the assessment of microelement accumulation in sturgeon pec...

The present study applies a bibliometric approach to identify recent patterns and trends in the methods, subjects, and authorships in the literature published in fisheries science (2000–2009). The results indicate that the most frequently studied group of species were Salmonidae, although the interest for these species seems to be diminishing. The...

Sterlet (Acipenser ruthenus L) populations in the Danube River had experienced severe decline during the 20th century, and have become dependant on stocking measures in significant area of their distribution. Despite the current wide use of stocking, there are few studies dealing with efficiency of stocking efforts, especially with impact of rearin...

This paper presents the status and trends in management of sturgeon species and the development of sturgeon aquaculture in the Lower Danube countries: Romania, Bulgaria, Serbia, Ukraine and Moldova. Sturgeon fishery moratoria and aquaculture development represent first steps in the Lower Danube countries to combat extirpation. Supportive stocking w...

Data on the presence of invasive species are often scarce, especially during the initial period following their introduction, when population abundance and species detectability are both still very low. In such cases, sporadic sightings in their newly occupied territory are often the only available information about their presence and distribution....

This study presents a population viability analysis (PVA) conducted on the Gironde population of Acipenser sturio using the Vortex software package. As identified by the model, the most important objects of the future research efforts related to A. sturio life history should be the determination of the mean fecundity, age at which females reach mat...

The accumulation of heavy metals in fish has been extensively studied and well documented. However, the research has been mainly focused on the muscle tissue, while the distribution patterns among other tissues, such as liver and gills, have been mostly neglected. Within the present study, the concentrations of Ag, Al, As, B, Ba, Cd, Co, Cr, Cu, Fe...

Sturgeon populations in the Danube River have experienced severe decline during the last several decades, mostly due to the poorly regulated fishery, river fragmentation and water pollution. This study focuses on gaining better understanding of sturgeon life history primarily by addressing the assessment of microelement accumulation in sturgeon pec...

The sterlet (Acipenser ruthenus L.) is a bottom-feeding fish species with a direct exposure to contaminants from water and sediments. Although heavy metal pollution is believed to be one of the main threats to the sterlet population in the Danube River basin, there is a lack of knowledge of the exact impact of heavy metals on their survival. In the...

Measurements of biomarker responses in fish from contaminated sites could provide valuable data for environmental risk assessment. Biomarkers are sensitive to both environmental pollution and confounding factors that are not related to pollution (e.g., season, nutritional status, and population density). Unfortunately, data about the latter group a...

The presence of Atlantic sturgeon (Acipenser sturio) and ship sturgeon (Acipenser nudiventris) in the Danube has been known through only occasional, chance sightings; significant uncertainty remains as to whether these species are already extinct or still present in the Danube River basin. In this study, five different statistical methods were appl...

Sturgeon species in the Danube River basin have experienced severe decline. Besides overexploitation, habitat loss, and pollution, they are further endangered by lack of efficient policy and management, as well as by serious lack of knowledge about their life history. Although population viability analysis (PVA) could represent an extremely valuabl...

The six native sturgeon species have been commercially harvested in the Danube Basin for more than 2,000 years, with rapid decrease in catch by mid 19th century. Additional negative effect on sturgeon populations in the Danube River was river regulation in Djerdap region, due to navigation in the late 19th century, as well as dam construction in th...

Whereas earlier Amur sleeper (Perccottus glenii) findings in the Danube River were only single specimens, data reported in this study represent the first record on establishment of a local population. An overview of the spread of the Amur sleeper in the Danube River basin is also presented.

Sturgeon populations in the Danube River have been affected by a combination of hydropower development, over-harvesting, habitat degradation from agricultural and industrial practices and from urbanization. The effects of these changes have been monitored on six sturgeon species inhabiting the Danube River. Two of them are resident species, while t...

On the 14th of June, 2005, in the Danube side channel "Jojkić" (N 44°50'33.1’’, E 20°27'46.1’’) near Belgrade, we recorded the presence of A. melas, ranging in weight (W) from 11.2 g to 135.6 g, and standard length (Ls) from 70 mm to 173 mm. Specimens were obtained from professional fishermen, who caught them with gill nets, as well from...

A comparative analysis was performed on sixteen morphometric characters, in three different juvenile sterlet Acipenser ruthenus L. populations. Specimens were collected from a wild population in the Serbian part of the Danube River (n = 46), from aquaculture stocks in the Czech Republic originating from Russia (n = 40), and aquaculture stocks in th...