Prussian Carp Carassius Gibelio Research Articles

The First Capture of the Prussian Carp Carassius gibelio (Cyprinidae) In Avacha Bay, Kamchatka

The First Capture of the Prussian Carp Carassius gibelio (Cyprinidae) In Avacha Bay, Kamchatka

First information about the fishes of lake butakovo (“Shushensky bor” national park)

An inventory of the biological diversity of specially protected natural areas is a necessary basis for understanding the patterns of formation and functioning of reference natural complexes, planning work on their monitoring and environmental protection measures, and also serves the objectives of educational work. Fishes of the Yenisei river basin has been relatively well studied, but there is no data about ichthyofauna of the water bodies of the Shushensky Bor National Park (located in the south of the Krasnoyarsk Territory). During this study in lake Butakovo, which is part of the lake-marsh massif “Shushensky Marshes“ on the territory of the Perovsky cluster of the Shushensky Bor National Park, 4 species of fish were noted. Of these, the prussian carp Carassius gibelio (Bloch, 1782), the crucian carp C. carassius (Linnaeus, 1758) and the tench Tinca tinca (Linnaeus, 1758) are typical fishes of the Minusinsk Hollow. The belica Leucaspius delineatus (Heckel, 1843) is alien species, relatively recently recorded in the Yenisei river basin. Finding of the belica in lake Butakovo is currently the southernmost recorded habitat of this invasive species in the Yenisei river basin. In the structure of the fish community in lake Butakovo is dominated by C. gibelio. It is super dominant both in numbers and in biomass. The C. carassius should be classified as the dominant species, and the T. tinca should be classified as common. The L. delineatus, which is 5% in number, due to its small size forms only 1% of the ichthyomass, while, according to the classification of Tereshchenko and Nadirov, it should be classified as a common species.

Tactics of Fish Behavior in the Water Flow during Starvation

Individual movement parameters for the zebrafish Danio rerio and the Prussian carp Carassius gibelio during starvation for 12 days have been determined in an experimental hydrodynamic installation circular tank. The fishes represent two tactics of behavioral responses on starvation. The tactics of unidirectional responses have been manifested in the movement of individuals in one direction relative to the water flow on days 2–5 of starvation. The tactics of multidirectional responses have been manifested on days 10–12 of starvation as movements in different directions relative to the water flow. The population advantages of such behavioral tactics of fish response to an unfavorable factor are considered.

Серебряный карась Carassius gibelio (Bloch, 1782) в Чарвакском водохранилище Узбекистана: морфологическая и молекулярно-генетическая характеристика

Morphological variability in response to environmental features is an important feature of alien species, increasing their adaptive capabilities and facilitating naturalization in new habitats. The prussian carp Carassius gibelio is currently very widespread in the world. Much of its current range is believed to be acquired as a result of human activity, with the prussian carp recognized as an invasive species capable of having a significant impact on recipient ecosystems. On the territory of Uzbekistan, prussian carp has been known in the lower reaches of the Syr-Darya and Amu-Darya since the 4th millennium BC, and was also recorded in the first half of the 20th century. However, its numbers were not large. In the 1960s, the Amur form of the prussian carp was introduced into the water bodies of Uzbekistan, as a result of a targeted introduction from the "Savvino" fish farm near Moscow and the accidental import of herbivorous fish with juveniles from the Russian Far East, after which its unauthorized resettlement began with planting material of cultivated cyprinids. In the 1970s, prussian carp found their way into the Charvak Reservoir. This is a mountain cold-water reservoir, formed on the Chirchik River (the right tributary of the Syrdarya River) and is located between the spurs of the Western Tien-Shan. With an area of only 37 km, it has a volume of about 2 km and a depth of more than 50 m. The reservoir is characterized by summer drawdown of the water level used for irrigation in the river valley Chirchik. This causes an almost complete absence of vegetation in the water area of the reservoir. Despite the atypical conditions, the prussian carp formed a self-sustaining population. There is none below the reservoir dam to the middle reaches of the Chirchik River. Indicators of counting characteristics of prussian carp in reservoir are D III-IV 17-19; A II 5-6; 26-30 (average 29) scales in the lateral line; on the first gill arch, 40-53 (on average 48) gill rakers and generally correspond to the characteristics in this climatic zone. Indices of plastic characteristics, both in traditional morphological analysis (see Table 1) and in the analysis of morphometric distances according to the “truss protocol” assessment method (see Table 2), do not have pronounced differences from the indicators of prussian carp living in a lowland reservoir Tudakul and in the fish ponds of the fish hatchery of the Research Institute of Fisheries of Uzbekistan. Analysis of the nucleotide sequences of the cyt b gene of prussian carp from the Charvak reservoir showed their similarity with samples from the upper reaches of the Yangtze river, China (see Table 3), which proves Far Eastern origin of prussian carp ih the Charvak reservoir. It is likely that it was the prussian carp, brought from the Far East, that ensured the growth in the number of the species in Uzbekistan. The question of the breadth of distribution of the Amur form of prussian carp in the region and the preservation of its native form currently remains open and requires further research using molecular genetic methods. The article contains 2 Figures, 3 Tables and 30 References. The authors are grateful to the directorate of the Institute of Zoology of the Academy of Sciences of Uzbekistan for creating conditions for the implementation of the planned scope of work. The Authors declare no conflict of interest.

A SHORT NOTE ON WATER QUALITY AND SOME BIODIVERSITY COMPONENTS IN GURBAN VALLEY, GIURGIU COUNTY

Several field trips were carried out in 2022 and 2023, aiming to investigate the water quality parameters, ichthyofaunal and floristic diversity in some areas of Gurban Valley, located in the protected area Natural Park Comana, Giurgiu County, southern Romania. Throughout the study period were identified fish specimens belonging to nine species: Prussian carp Carassius gibelio (Bloch, 1782); Gobio obtusirostris Valenciennes, 1842; Dnieper chub Petroleuciscus borysthenicus (Kessler, 1859); Roach Rutilus rutilus (Linnaeus, 1758); Danubian spined loach Cobitis elongatoides Băcescu & Mayer, 1969; Belica Leucaspius delineatus (Heckel, 1843); Southern ninespine stickleback Pungitius platygaster (Kessler, 1859); European bitterling Rhodeus amarus (Bloch, 1782) and European mudminnow Umbra krameri Walbaum, 1792. A total of 147 captured specimens were measured, weighed and photographed. For the capture of fish, minnow traps and plankton nets were used, on the Gurban River, right tributary of the Neajlov River, Giurgiu County. The floristic inventory compiled so far included 58 plant species grouped into 31 families, with European, circumpolar, Eurasian, eurasiatic continental or cosmopolitan distribution. Related to physico-chemical characterization of water samples collected from four sampling points (SP), the results of laboratory analysis allowed to frame the water into quality classes and to evaluate if the water meets the requirements for aquatic organisms. Hence, on the basis of nitrite-nitrogen (N-NO2-) and nitrate-nitrogen (N-NO3-) water corresponds to Ist quality class, meanwhile chemical oxygen demand (COD), phosphate-phosphorus (P-PO43-) and ammonium-nitrogen (N-NH4+) allowed to associate water quality with IIIrd class. In addition, it has been found very significant correlations between electrical conductivity (EC) and total hardness (TH) with r=0.9230*** and between pH and TH with r=0.8821***, respectively.

Mass mortality events associated with cyprinid herpesvirus 2 (CyHV-2) infection in wild Prussian carp Carassius gibelio in the Netherlands, and molecular biology of virus strains.

In 2011 and 2015, four mass mortalities of Prussian carp (Carassius gibelio) were observed in a recreational freshwater lake and open freshwater in the western part of the Netherlands. Cyprinid herpesvirus 2 (CyHV-2) infection was suspected in these cases, based on presumptive gross diagnosis. To elucidate the cause of the mass mortalities diagnostic PCR assays were performed for CyHV-2, based on the helicase gene. Furthermore, the viral isolates were genotyped by sequencing the enlarged marker A and marker B sequences. Diagnostic PCR revealed that three of four samples were positive for CyHV-2, indicating these three mass mortalities were associated with CyHV-2 infection. The marker A sequence from one of the isolates found in this study was identical to those from different locations such as Asia and Middle East, suggesting a link among the isolates. This is the first detailed report on mass mortalities of Prussian carp associated with CyHV-2 infection in natural aquatic environments in the Netherlands. Since 2015, additionally, in total three CyHV-2 associated outbreaks of Dutch Prussian carp were seen in 2016 and 2020. These outbreaks in Prussian carp from lakes and open water suggest that the virus has been spreading in natural freshwaters in the Netherlands.

The influence of some ecological factors on fish diversity and abundance in Al-Huwyzah marsh / South of Iraq

From January to December 2019, the composition of fish assemblages in Al-Huwyzah marsh was studied in various ways based on the nature of their life-history strategies. In orders to assess the impact of hydrological variations on fish assemblage composition, diversity, and abundance. Water temperature fluctuated from 12°C in January to 33°C in July. Salinity varied from 1.38 g/l in March to 3.87 g/l in November. Hydrogen ion fluctuated from 7.37 in November to 8.18 in December. Monthly fluctuations in water depth were monitored for flat sections and low-lying areas of the marsh. Fish assemblages in Al-Huwyzah marsh were studied to determine the impact of hydrological and environmental changes on the pattern, abundance, diversity, and richness of fish assemblages. Fixed, drift, and cast gillnets were used to catch the fish. Nine thousand eight hundred fifty-three fish specimens belonging to 18 species, 17 genera, ten families, and six orders were caught from the three selected stations. All of which belonged to the Osteichthyes class. Ten fish species were native, and eight were exotic species. The Abu mullet Planiliza abu was the most abundant species comprising 35.74% of the total number of species, Prussian carp Carassius gibelio 19.74% of the total caught, and blue tilapia Oreochromis aureus 19.23%. The dominance index (D3) ratio is 74.71% of the upper abundance of three fish species in the present area. The equilibrium strategists that prefer stable habitats with a long time breeding season include abundant exotic species, and opportunistic strategists comprise one species of present fish assemblage. Keywords: Assemblage of fish; Huwyzah marsh; Hydrological variations

Hematological and Genotoxic Indicators of the Freshwater Beam Abramis brama and Prussian Carp Carassius gibelio (Cyprinidae) in the Volga Delta

Hematological and Genotoxic Indicators of the Freshwater Beam Abramis brama and Prussian Carp Carassius gibelio (Cyprinidae) in the Volga Delta

Hematological and Genotoxic Indicators of the Freshwater Beam Abramis brama and Prussian Carp Carassius gibelio (Cyprinidae) in the Volga Delta

The occurrence of erythrocytes with micronuclei and DNA damage was detected by the comet assay in freshwater bream, Abramis brama, of age 3–4, and prussian carp, Carassius gibelio, of age 4–5 from Volga delta in September 2021. The average frequency of erythrocytes with micronuclei in the studied fish es was within the normal range for cells formed during spontaneous mutagenesis (0.5–1.0‰). Further, 25% freshwater bream and 26.6% Prussian carp exceeded this limit. The genetic damage index (GDI), which reflects primary DNA damage, was 0.21 ± 0.03 and 0.26 ± 0.02 in freshwater bream and Prussian carp, respectively. Further, it correlated (r = 0.71, p 0.05) in Prussian carp with the occurrence of erythrocytes with micronuclei. Hematological and biochemical parameters of the mentioned species were within typical limits for fishes residing in water bodies with a weak anthropogenic load. The results allow considering the existing conditions of the freshwater bream and Prussian carp in the Volga delta as quite favorable in relation to the genotoxic situation.

РЕТРОСПЕКТИВНЫЙ АНАЛИЗ ИХТИОФАУНЫ РЕКИ ТОМЬ В ПРЕДДВЕРИИ СТРОИТЕЛЬСТВА КРАПИВИНСКОГО ВОДОХРАНИЛИЩА

The resumption of design and survey work for the construction of the Krapivinsky Hydroelectric Power Plant on the Tom River has necessitated the assessment of the current state of its fish resources and called for making the prediction of their transformation in the event of the hydroelectric complex being put into operation. In the early 20th century, the Tom River was classified as a salmonid habitat. At that time, such valuable commercial species as the Siberian taimen Hucho taimen, blunt-snouted lenok Brachymystax tumensis , tugun Coregonus tugun, humpback whitefish Coregonus pidschian, Nickolsky’s grayling Thymallus nikolskyi , nelma Stenodus leucichthys nelma, muksun Coregonus muksun, and peled Coregonus peled were permanent residents. Sturgeons, such as the Siberian sturgeon Acipenser baerii and sterlet Acipenser ruthenus, were also abundant. Currently, out of these species, grayling, occasionally taimen and lenok are caught in the Tom River; the common roach Rutilus rutilus , European perch Perca fluviatilis, Siberian dace Leuciscus baicalensis and Eurasian ruffe Gymnocephalus cernuus comprise 95 % of all fish caught. If construction of the Krapivinsky Reservoir on the Tom River is completed and it is put into operation, a deep-water, slow-flowing “lake-type” water body will be created. The river bed will be blocked, so semi-anadromous fish species, many of which are listed in the Red Data Book-such as Siberian sturgeon, sterlet and nelma,-will disappear. A decrease in the abundance of grayling, taimen and lenok, already low in number, should also be expected. These fish species winter in the pits, some of them migrate to the Ob River, so, after passing the spillway, they will not be able to return upstream to the spawning grounds. The abundance of lake and lake-river species is expected to increase, among them the common roach, dace Leuciscus leuciscus , European perch, Prussian carp Carassius gibelio (introduced locally, subsequently self-dispersed), as well as common bleak Alburnus alburnus and sunbleak Leucaspius delineates (accidental invaders). In the future, it is possible to make an attempt to introduce peled to the upper basin of the Krapivinsky Reservoir. There is a prospective threat of the Chinese sleeper Perccottus glenii spreading in the upcoming reservoir, which can severely undermine its fish stocks.

Myxobolus lentisuturalis infection in a farmed population of goldfish Carassius auratus from the USA.

Myxobolus lentisuturalis is a myxozoan parasite of piscine muscle that has been described in goldfish Carassius auratus and Prussian carp Carassius gibelio. This report documents a naturally occurring infection of M. lentisuturalis in a population of farmed goldfish in the USA. Postmortem examination was performed on 4 affected goldfish. Gross findings included large cystic cavities along the dorsal midline filled with caseous exudate. Histopathology revealed myxozoan plasmodia and spores in the epaxial muscles with varying degrees of granulomatous and necrotizing myositis accompanied by lymphohistiocytic meningoencephalitis. Spore morphology and dimensions were consistent with M. lentisuturalis, as observed by light microscopy. PCR and sequence analysis of the small subunit ribosomal DNA of infected muscle samples from 2 goldfish confirmed the parasite to have 99-100% nucleotide identity to M. lentisuturalis sequences recovered from similar cases of this parasite infecting goldfish in China and Italy and Prussian carp in China. This is the first reported case of M. lentisuturalis in the USA and furthers the understanding of the pathogenicity of this under-described parasite.

СТРУКТУРНI ПОКАЗНИКИ ПОПУЛЯЦІЇ КАРАСЯ СРІБЛЯСТОГО (CARASSIUS GIBELIO B.) КРЕМЕНЧУЦЬКОГО ВОДОСХОВИЩА

Ukraine ranks first in Europe in the number of natural water bodies. These abundant water resources are the source of significant fish resources, which are effectively exploited by the fishing industry. Rationalization and equal distribution of the commercial load, the reduction of the commercial pressure on the main fish species has always been an urgent issue. This can be achieved by shifting the focus of fishing to other types of fish, which will allow rational use of the entire complex of commercial species. The Prussian carp Carassius gibelio (Bloch, 1782) is among such promising objects of fishing - a massive, small-particle species, which in certain water bodies of Ukraine has displaced other minor commercial fish species and formed stable numerical populations. 
 A decisive role in the age structure formation of the Prussian carp population was played by the increase in the specific number of middle and older age groups, which is associated with an insufficient level of commercial load. Thus, the variation series of this species in the commercial catches of 2021, unlike other species, had the form of a double-peaked curve, which was formed due to the loss of size classes of 25-28 cm. According to the Fishing Rules and the Regime of Fishery Operation of the Dnipro Reservoirs in force today, nets with a step are allowed hole a=38-49 mm and 70 mm and more. This distribution of commercial load selectivity reduces pressure on bream and bream populations. However, it also causes a significant increase in the stock of Prussian carp. And this alien species has formed abundant populations in the Kremenchuk Reservoir. Thus, its average annual catch in the period 2000-2020 increased from 44.6 to 462.4 tons or 10 times in 20 years. 
 We should note that Prussian carp occupied an insignificant segment of the catch - no more than 0.1% by weight in the traditional commercial set of gill nets (a=75-90 mm) at the Kremenchuk Reservoir, while, in the 50-60 mm mesh size nets this species is dominant with a share in catches of up to 60% by weight. Thus, the main indicators that characterize the fisheries and environmental protection components of gill net fishing are a mesh size that deals with part of the main target fishing objects, size and weight indices, and bycatch of immature commercially valuable species. The gill nets with 50-60 mm generally meet the requirements for the current legislation and might be used for targeted harvest of the species in the littoral zones. Considering the need to intensify fishing for Prussian carp and its high actual specific mass in catches of nets with a mesh size of 50-60 mm, the implementation of specialized fishing for this species in the Dnieper reservoirs can be considered as a means of optimizing the use of the formed bioresource for the commercial fishery. In order to minimize the negative impact of this fishing on the structural and functional indicators of the bream population, specialized fishing should be focused on the areas of accumulation of Prussian carp, i.e. it is a specialized fishery with a share of Prussian at least 50%. The necessity of the meliorative capture introduction aimed to downgrade the reproductive core of the population of this alien species to prevent its uncontrolled population growth.

Food composition and feeding strategies of an invasive species, Carassius gibelio (Bloch, 1782) inhabiting a eutrophic lake in Middle Black Sea region

Diet composition and feeding features of the Prussian carp Carassius gibelio (Bloch, 1782) were studied by analysing the stomach content of 155 fish specimens sampled from Lake Ladik during November 2009-October 2010. Five of the specimens had empty stomachs. A total of 29 prey taxa belonging to eight major groups comprising aquatic insects, Copepoda, Cladocera, Rotifera, Bacillariopyhta, Chlorophyta, Cyanobacteria and fish eggs were identified in 150 full stomachs. Diet composition showed slight seasonal variation. Cladocera was the most important prey item in all seasons, with peak abndance in spring. Feeding intensity exhibited seasonal change and was maximum in summer. Summer and autumn diets of this species showed the highest similarity. The study indicated that the Prussian carp in Lake Ladik showed both omnivorous and opportunistic feeding habits, exhibiting specialised feeding strategy on Cladocera, while they showed generalised feeding strategy on most prey items. The wide dietary plasticity of invasive Prussian carp can help their population to expand rapidly in different aquatic ecosystems. Keywords: Alien species, Diet composition, Feeding habits, Lake Ladik, Prussian carp

First record of microplastic occurence at the commercial fish from Orontes River

Freshwater environments are more sensitive to anthropogenic influences and usually contain higher concentrations of pollutants than marine environments. Microplastic pollution causes additional stress on freshwater animals; yet, studies evaluating the microplastic occurrence in freshwater biota are still limited. In this study, microplastic occurrence in the gastrointestinal tracts (GIT) and gill of commercial fish species (Prussian carp Carassius gibelio (Bloch, 1782); Abu mullet Planiliza abu (Heckel, 1843); Common carp Cyprinus carpio Linnaeus, 1758; European ell Anguilla Anguilla (Linnaeus, 1758); North African catfish Clarias gariepinus (Burchell, 1822); Goldfish Carassius auratus (Linnaeus, 1758) were reported from Orontes River. MPs abundance in the GIT and gill of six species were found as 5.1 ± 2 MPs fish−1 and 4.4 ± 2 MPs fish−1 with an occurrence of 95% and 74%, respectively. The majority of extracted microplastics were fiber, black and less than 1000 μm in size. FTIR analysis determined the main polymer types as polyester (50%), high-density polyethylene (HDPE) (10%), polypropylene (PP) (8%) and polyethylene terephthalate (PET) (5%). High MPs abundance and frequency of occurence indicate the exposure of microplastic pollution in freshwater biota which could threat the health of both individuals and consumers. Results obtained in this study will increase the acknowledgement of MPs pollution in the Orontes River. Also, this study will provide data to the administrators to set up necessary legislations in freshwater ecosystems.

Інвазивні види риб у річках басейну Західного Бугу в межах України

Purpose. To determine the occurrence of invasive fish species in ichthyofauna of rivers of the Western Bug basin in Ukraine. Methodology. Ichthiological studies were carried out during 2019-2021 in the Western Bug River and on its tributaries - Rata, Bushkov, Poltva and Mlynivka. Fish species identification was carried out in situ and was performed according to the identification keys of Yu.V. Movchan and A.F. Koblytska, incomplete biological analysis of invasive species was performed in the laboratory according to the methods of I.F. Pravdin, G.V. Nikolsky and I.I. Chugunova. Findings. The obtained data showed that invasive species in the composition of ichthyofauna in the studied rivers of the Western Bug basin were represented by five species: Prussian carp Carassius gibelio (Bloch, 1782), Stone moroko Pseudorasbora parva (Temminck & Schlegel, 1846), Pumkinseed Lepomis gibbosus (Linnaeus, 1758), Chinese sleeper Perccottus glenii Dybowski, 1877, Monkey goby Neogobius fluviatilis (Pallas, 1814). These species entered the ecosystem due to human activities through deliberate or accidental introduction into rivers of the Western Bug basin, where conditions are quite favorable for their vital activity and growth, due to a fairly warm climate and changes in hydrological regime of many rivers as a result of human impact. Originality. The article presents for the first time a list of invasive fish species of rivers of the Western Bug basin in Ukraine and provides a description of their habitats. Practical value. The obtained results can be used to regulate recreation fishery, for planning of conservation measures for rare fish species and for planning prevention of negative consequences from the spread of invasive fish species. Key words: ichthyofauna, the Western Bug River, invasive alien species, Prussian carp, Stone moroco, Pumkinseed, Chinese sleeper, Monkey goby.

Potentially toxic elements in invasive fish species Prussian carp (Carassius gibelio) from different freshwater ecosystems and human exposure assessment.

Concentrations of Al, As, Cd, Co, Cr, Cu, Fe, Hg, Mn, Ni, Pb, Se, Sn, and Zn were detected in the muscle and gills of Prussian carp from three different freshwater ecosystems: isolated ponds and the South Morava River in Serbia, and Kopačko Lake in complex wetland ecosystem of the Kopački Rit Nature Reserve in Croatia. The main goals of the present research were to assess the concentrations of potentially toxic elements (PTEs) in the muscle and gills of Prussian carp (Carassius gibelio), to examine whether abiotic factors from three different freshwater ecosystems affect the accumulation of PTEs in fish tissues, and to estimate the human health risk resulting from fish consumption. There were only six concentrations of PTEs in the gill tissue (Cr, Hg, Mn, Pb, Sn, and Zn) that were not significantly different among the different freshwater ecosystems. In the muscles, the differences were much less visible. Kopačko Lake distinguished with the highest values of metal pollution index (MPI) for muscles (0.24) and isolated ponds with the highest values of MPI for gills (0.8). The redundancy analysis (RDA) showed that concentrations of Al, Mn, Zn, Cu, and Fe in the gill tissue were significantly correlated with the environmental variables. In contrast, the RDA based on element concentrations in the fish muscles indicated no significant relationship with the environment. Isolated ponds, with no inflow of freshwater, stand out as the most polluted, followed by Kopačko Lake with occasional floods. Flowing freshwater ecosystem South Morava River can be single out as at least polluted with PTEs. The target hazard quotients (THQ) and hazard index (HI) suggested there were no significant noncarcinogenic health risks. The target carcinogenic risk factor (TR) for As and Pb confirmed there were no cancer risks related to human fish consumption. Since the elevated concentrations of toxic Cd and As in Prussian carp were estimated, an early warning should be assumed, especially for fishing activities in these areas.

Evaluation of fish assemblages’ composition in the Euphrates River, southern Thi-Qar province, Iraq

Fish assemblage composition in the Euphrates River southern Thi-Qar province was assessed from January to December 2018. Various fishing methods were used to collect the samples. A total of 3010 specimens of bony fishes were caught represented 17 species, 17 genera, ten families and six orders. The species included ten native fish species and seven exotic fish species. The Abu mullet Planiliza abu was the most abundant species formed 26.21% of the total caught, blue tilapia Oreochromis aureus 19.30%, Prussian carp Carassius gibelio 17.48% and Redbelly tilapia Coptidon zillii 13. 29% of the total number of species. The dominance index (D3) value of the highest abundance represented by three fish species that preside the study area forming 62.99%, there are P. abu, O. aureus and C. gibelio. The occurrence of fish species contained seven fish species formed 92.03% of the total species caught. Seasonal fish species comprised of three fish species included 6.51% and occasional fish species contained seven species represented 1.46% of the total number of species. The diversity index values appear as poor ranged from 1.59 in December to 2.07 in April. Richness index values pointed to disturbing status, varied from 1.21 in September to 2.00 in May. Evenness index tends to be balanced, fluctuated from 0.79 in June to 0.91 in February and July. The present study verified the prevalence of the small-sized tolerance fish species represented by one native and three exotic species, with rarely or absence of the keystone native fish species of fish communities predominating the south of Iraq.

Variability of Composition of Microbiota of Gastrointestinal Tract of Perch Perca fluviatilis and Prussian Carp Carassius gibelio During the Vegetative Season

Variability of Composition of Microbiota of Gastrointestinal Tract of Perch Perca fluviatilis and Prussian Carp Carassius gibelio During the Vegetative Season

Advancing improvement in riverine water quality caused a non-native fish species invasion and native fish fauna recovery

The knowledge of biotic and abiotic drivers that put non-native invasive fishes at a disadvantage to native ones is necessary for suppressing invasions, but the knowledge is scarce, particularly when abiotic changes are fast. In this study, we increased this knowledge by an analysis of the biomass of most harmful Prussian carp Carassius gibelio in a river reviving from biological degradation. The species' invasion followed by the invasion's reversal occurred over only two decades and were documented by frequent monitoring of fish biomass and water quality. An initial moderate improvement in water quality was an environmental filter that enabled Prussian carp’s invasion but prevented the expansion of other species. A later substantial improvement stimulated native species’ colonization of the river, and made one rheophil, ide Leuciscus idus, a significant Prussian carp’s replacer. The redundancy analysis (RDA) of the dependence of changes in the biomass of fish species on water quality factors indicated that Prussian carp and ide responded in a significantly opposite way to changes in water quality in the river over the study period. However, the dependence of Prussian carp biomass on ide biomass, as indicated by regression analysis and analysis of species traits, suggests that the ecomorphological similarity of both species might have produced interference competition that contributed to Prussian carp’s decline.

To the biology of the Prussian carp Carassius gibelio (Bloch, 1782) in the Middle Ob river basin

Information about some features of the Prussian carp Carassius gibelio (Bloch, 1782) in three different floodplain lakes in the Middle Ob river basin are presented. Individuals of younger age groups predominate in populations. Fish over the age of 9+ are not noted. The ratio of females to males is different, from 4:1 to 8:1, always in favor of females, which is typical for Prussian carp populations in Western Siberia. There were specimens in the sample from 152 to 355 mm long and weighing from 115 to 1250 g. When comparing males and females of the same age, the latter are generally larger. The noted size characteristics — 335 mm and 1250 g — are the maximum of the published data for Prussian carp Carassius gibelio in the Middle Ob river basin. When comparing individuals of the same age, it was shown that Prussian carp Carassius gibelio is a larger size in the big not-frozen lake Monatka than in the small, frozen lakes Zmeevo and Taskino. The maturity of female Prussian carp Carassius gibelio in floodplain lakes of the Middle Ob river basin occurs at the age of 3+, but some 2+ were mature. At the age of 4+, all specimens in the samples were sexually mature. Sexual dimorphism Prussian carp from lake Monatka is weakly expressed: in males, the length of the head, the height of the dorsal and the length of the pectoral fins are statistically significantly greater. A higher dorsal fin can be considered a characteristic feature of the male Prussian carp in the south of Western Siberia in comparison with the females.