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Within the genus Carassius Jarocki, 1822 , the crucian carp (C. carassius L., 1758) occurs naturally in the northern part of Middle Danube Basin (Austria, Morava, Slovakia). This species has the least concern status in this region, but observations in the last decades suggest that it is very close to extinction here. The distribution of crucian carp is limited to a small number of vanishing lentic habitats (oxbow lakes, marshlands). These biotopes are in the last stage of succession due to the drying up of the landscape and a reduction in the creation of new natural alluvial habitats. The non-native cyprinid, C. gibelio (Bloch, 1782), known as gibel carp and Prussian carp, has gradually become eudominant in a wide spectrum of habitats/biotopes since the 1960s Several biological adaptations of non-native species are generally considered the strong basis for the mass spreading in the invaded area. The other side of the expansion of non-native C. gibelio is affected by anthropic activities associated with fish farming, translocation and stocking the fish in open water ecosystems. In this study, we analysed historical scientific data on the distribution of Carassius spp. published from the 19th century to the present from the mentioned areas. The results suggest that the number of records of invasive C. gibelio has gradually increase in rivers, regulated channels and creeks, which could be considered as natural pathways of spreading. However, the presence of invasive C. gibelio in artificial biotopes (fishponds, reservoirs) is continuous from the 1960s. In the area mentioned, the artificial biotopes are managed by national fisheries associations and relate to the historical way of farming in Central and Eastern European countries. To show the current state of the fishing grounds of the Slovak Angling Association, we a created the distribution map based on the Carassius spp. catches recorded in last two decades.

Carassius gibelio (Bloch, 1782) Remarks. This species is widely introduced in Europe and Asia. It is probable that it was also introduced via transboundary waterways. The presence of the species needs clarification., Published as part of Çiçek, Erdoğan, Fricke, Ronald, Eagderi, Soheil, Sungur, Sevil, Coad, Brian W & Hamdard, Mohammad Hamid, 2023, Fishes of Afghanistan; a revised and updated annotated checklist, pp. 1-69 in Zootaxa 5305 (1) on page 51, DOI: 10.11646/zootaxa.5305.1.1, http://zenodo.org/record/8048564

Carassius auratus (Linnaeus, 1758) [I]—Goldfish Taxonomy. Original description: Cyprinus auratus Linnaeus, 1758: 322 [China; Japanese rivers; no types known].— Afghanistan synonyms: None.—Revisions: None.—Illustration: Guo (2021: 472, fig.). Status in Afghanistan. First record from Afghanistan by Moravec and Amin (1978); confirmed by Coad (1980; 1981: 9; 2014: 318).—Afghanistan materials: CMN. Distribution and habitat. Distribution in Afghanistan: Kabul River basin, Sistan, Pishin Lora drainage, Amu Darya drainage.—General distribution: East Asia: China and Japan; introduced widely elsewhere; many cultivated goldfish varieties.—Habitat: This species inhabits rivers, lakes, reservoirs, ponds and ditches with stagnant or slow-flowing water. It occurs in eutrophic fresh and brackish waters, well vegetated ponds and canals. Freshwater. Economic importance. Valuable for the aquarium trade. Conservation. Not relevant (introduced species)., Published as part of Çiçek, Erdoğan, Fricke, Ronald, Eagderi, Soheil, Sungur, Sevil, Coad, Brian W & Hamdard, Mohammad Hamid, 2023, Fishes of Afghanistan; a revised and updated annotated checklist, pp. 1-69 in Zootaxa 5305 (1) on page 22, DOI: 10.11646/zootaxa.5305.1.1, http://zenodo.org/record/8048564, {"references":["Linnaeus, C. (1758) Systema Naturae. Vol. 1. Ed. X. [Systema naturae per regna tria naturae, secundum classes, ordines, genera, species, cum characteribus, differentiis, synonymis, locis. Tomus I. Editio decima, reformata]. Impensis Direct. Laurentii Salvii, Holmiae, ii + 824 pp.","Guo, Y. - S. (2021) Colored atlas of fishes of Sichuan. Vol. I. Sciencepress, China. China Scientific Book Services, Beijing, 475 pp.","Moravec, F. & Amin, A. (1978) Some helminth parasites excluding Monogenea from fishes of Afghanistan. Acta Sci Nat Brun, 12, 1 - 45."]}

The aim of the investigation was to study the current structure of the parasitic fauna of the gibel carp (Carassius gibelio) population in the Georgian part of Jandari Lake. In total, 423 young gibel carp collected during 2014-2018 years from Jandari Lake have been subject to parasitological examination. The 20.3% (n=86) of examined fish were invaded by 11 species of parasites belonging to 5 taxonomic groups. The dominant taxonomic groups were discovered to be Protozoa and Monogenea. The eight species were registered for the first time in the gibel carp of freshwater reservoirs in Georgia. In general, young fish were more invaded by the monoxenic species of the direct life cycle. None of the revealed parasites were specific to gibel carp. The parasitic fauna of Jandari Lake is relatively poor, though it is comparatively rich and diverse in spring. Trichodina sp. from Protozoa, Ancyrocephalus sp., Dactylogyrus vastator, Gyrodactylus elegans from Monogenea, and Contracaecum sp. from Nematoda were revealed as the species most sensitive to annual changes. The main factor determining the parasite fauna of gibel carp in Lake Jandari is anthropogenic eutrophication, which changes the qualitative and quantitative composition of zooplankton, the main food source of juvenile fish and intermediate hosts of helminths. The difference in invasion indices between female and male gibel carp was insignificant. The synergetic relationship between some parasitic protozoans and monogeneans was marked.

Ecologoparasitological research was done based on the helminths and helminth communities of the Prussian carp (Carassius gibelio (Bloch, 1782)) from the freshwater ecosystem of the Panicheri Reservoir, Aegean Water Basin, Bulgaria. As a result of the examined nine specimens of the Prussian carp, two species of helminths were found: Ligula intestinalis (Linnaeus, 1758), larvae and Pomphorhynchus laevis (Müller, 1776). The dominant structure of the helminth communities was determined. The Panicheri Reservoir is a new habitat in Bulgaria of P. laevis and L. intestinalis from C. gibelio. C. gibelio is a new host record for L. intestinalis in Bulgaria. The two helminth species are core species for the helminth communities of the examined species of the freshwater fish. P. laevis was distinguished with higher prevalence and mean intensity (P%=33.34; MI=1.34) than L. intestinalis (P%=22.23; MI=1.0). The circulatory pathways of the helminth flow were traced.

Information about ploidy is important in both commercial and conservation aquaculture and fish research. Unfortunately, methods for its determination, such as karyology, determination of the amount of DNA in a cell using microdensitometry or flow cytometry and/or measuring erythrocytes in a blood smear can be stressful or even destructive. Some of these methods are also limited by the relatively large minimum size of the individual being measured. The aim of this study was to test a new low-stress method of determining ploidy by measuring the size of erythrocytes in the capillaries of a fish, including small individuals. First, we examined diploid and triploid loach (Cobitis sp.) and gibel carp, Carassius gibelio (Bloch, 1782), using flow cytometry and blood smears, with these results being used as a control. Subsequently, we measured the size of erythrocytes in the caudal fin capillaries of anesthetized fishes of known ploidy under a light microscope. For both the loaches and gibel carp, direct observation of the mean erythrocyte size in epithelial fin capillaries provided a consistent and reliable determination of ploidy when compared with the controls based on flow cytometry and blood smears. This new method allows for rapid determination of ploidy in living small fish, where collection of tissue using other methods may cause excessive stress or damage. The method outlined here simply requires the measurement of erythrocytes directly in the bloodstream of a live fish, thereby making it possible to determine ploidy without the need for blood sampling. The method described is sufficiently efficient, less demanding on equipment than many other procedures, can be used by relatively inexperienced personnel and has benefits as regards animal welfare, which is especially important for fish production facilities or when dealing with rare or endangered species.

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.

Improvement in fish feed conversion efficiency (FCE) is beneficial for sustaining global food fish supplies. Here, we show that a set of polymorphisms at locus of the corticotropin releasing hormone receptor 2 (crhr2), which is involved in hypothalamus-pituitary-interrenal (HPI) axis signaling, is associated with improved FCE in farmed allogynogenetic gibel carp strain CAS III compared with that in the wild gibel carp strain Dongting (DT). This set of polymorphisms downregulates the expression levels of crhr2 mRNA in the brain and pituitary tissues in gibel carp strain CAS III compared with those in strain DT. Furthermore, compromised HPI axis signaling is observed in gibel carp strain CAS III, such as decreased α-melanocyte stimulating hormone protein levels, plasma cortisol content, and stress responses. Moreover, enhanced activation of protein kinase B/mammalian target of rapamycin complex 1 signaling observed in the muscle tissue of strain CAS III in comparison to that in strain DT indicated elevated anabolic metabolism in strain CAS III. Thus, these studies demonstrate that the genetic markers associated with compromised HPI axis signaling, such as crhr2, are potentially useful for genetic selection toward improvement in farmed fish growth and FCE, which would reduce fishmeal consumption and thereby indirectly facilitate sustainable fisheries.

The objective of the present study was to assess if trypsin, a key enzyme involved in protein digestion, presents some kind of functional adaptations to seasonal changes in water temperature in freshwater fish. In order to test this hypothesis, individuals of two fish species Carassius gibelio (agastric) and Perca fluviatilis (gastric) were sampled in the basin of Chany Lake (Siberia, Russia) at two different seasons (spring and summer). Apparent kinetic parameters (Km and Vmax) were determined for both species and seasons at the actual pH values in fish guts, and at actual temperatures. Results showed a significant effect of both the species and sampling season on the apparent kinetic parameters of trypsin. In the case of Prussian carp, Km and Vmax were lower for each assayed temperature (for 5 and 15 °C the differences were significant) for fish sampled in summer when compared to those sampled in spring. In contrast, values of Km in perch tended to be lower in spring at 5 and 25 °C but these differences were not significant, while Vmax showed a significant decrease in summer samples. This suggests a sort of functional adaptation of the same trypsin enzymes to seasonal changes, oriented to maximize protein digestion under variable conditions.

The introduction of invasive fish species is considered to be one of the major causes of species endangerment in aquatic ecosystems. More than 30 non-native freshwater fish species which are introduced for the different purpose were reported in Turkey. In addition to the freshwater non-native fish species, the brackish water systems are also affected by the fish species that enter the Mediterranean Sea through the Suez Canal. This study aimed to identify non-native fish species introduced in the Mediterranean brackish water systems of Turkey. Thirteen non-native species from eleven families were identified from 15 localities along the entire Mediterranean Coast of Turkey between 2014-2017. These species are Carassius gibelio (Bloch, 1782), Pseudorasbora parva (Temminck & Schlegel, 1846), Coptodon zillii (Gervais, 1848), Oreochromis niloticus (Linnaeus, 1758), Gambusia holbrooki Girard, 1859, Oncorhynchus mykiss (Walbaum, 1792), Chelon carinatus (Valenciennes 1836), Equulites klunzingeri (Steindachner, 1898), Upeneus moluccensis (Bleeker, 1855), Upeneus pori Ben-Tuvia & Golani, 1989, Siganus rivulatus Forsskål & Niebuhr, 1775, Sillago suezensis Golani, Fricke & Tikochinski, 2013 and Sphyraena chrysotaenia Klunzinger, 1884. The most widely distributed non-native fishes were Gambusia holbrooki, Chelon carinatus, and Carassius gibelio. Of the 15 localities surveyed Lessepsian fish species were sampled from 9 localities.

Hematological parameters are quite effective and informative for determining the health status of fish populations. They respond quickly to changes in habitats of different nature. The Prussian carp is one of the most widespread species in the Ukrainian reservoirs. Currently, the researches of hematological changes of this species in the modern conditions of the Zaporizhyian (Dnipro) reservoir are quite relevant. During the research the ecological classification of surface water quality in Ukraine, it was found that the water in the Samara Bay is characterized as "moderately polluted", and in the lower part of the reservoir it is "slightly polluted". The concentration of almost all investigated heavy metals in the water of the Samara Bay is higher compared to the lower part of the reservoir. The number of erythrocytes and hemoglobin content in the blood of Samara Bay fish were lower by 22.4% and 44%, respectively, compared to fish in the lower part of the Zaporizhian (Dnipro) reservoir, and the erythrocyte sedimentation rate was higher by 81.8%. In the Prussian carp from the silver Zaporizhian (Dnipro) reservoir, neutrophilic leukocytosis with a shift to the left was observed, which is usually characteristic of inflammatory processes and various intoxications. There were also statistically significant deviations in the activity of ALT and AST in the blood plasma of fish in the Samara Bay, which may indicate a chronic impact of a complex of anthropogenic factors on fish, especially on the function of the liver, which serves as a detoxifying organ.

Purpose. To determine the presence of functional changes in the cytometric and biochemical parameters of the blood of Prussian carp of the Samara River under conditions of human impact. Methodology. The object of the study was age-6 Prussian carp (Carassius gibelio (Bloch, 1782)) of both sexes. The material for the study was collected with the use of gill nets during scientific fishing in the summer-autumn period in 2019. Blood was collected from the caudal vein. Morphological studies of erythrocytes were carried out on blood smears, which were stained according to Romanovsky-Giemsa. Blood smears were studied at 40X magnification using a photomicrograph with a Sciencelab T500 5.17 M digital camera. On the preparations, 150 visual fields were examined. Biochemical studies were carried out on automatic analyzers OLYMPUS AU400 and AU480 from BeckmanCoulter (USA), using BeckmanCoulter reagents. Statistical processing of the data obtained was carried out according to generally accepted methods in MS Excel 2010. Findings. Age-6 Prussian carp (Carassius gibelio (Bloch, 1782)) of the Samara river, under conditions of anthropogenic impact, were found to have an increase in their glucose content (28.5 - 37.4 mmol/l), as well as an increase in ALT (46.5 - 52.8 U/L) and AST (85.1 - 100.5 U/L) activities in blood that may indicate the formation of certain protective mechanisms for adaptation to the effects of harmful environmental factors. These parameters were highest in specimens caught near Novomoskovsk. Cytometric analysis showed a statistically significant increase in the nuclear weight, the size of erythrocytes and an increase in the nuclear-plasma ratio of red blood cells of fish caught near the village Khashchove and Novomoskovsk. It can indicate the inhibition of the functional activity of erythrocytes. The value of the albumin-globulin coefficient (0.6) and the de Ritis coefficient (1.8 - 1.9) of Prussian carp at all experimental points of the Samara river indicates the beginning of the formation of certain pathological processes in their liver and heart. Originality. The study of cytometric and biochemical parameters of the blood of Prussian carp of the Samara river of the Dnepropetrovsk region subjected to the significant human impact was performed for the first time Practical value. The data obtained can be used to conduct hydroecological monitoring of natural water bodies and to determine the degree of the effect of various anthropogenic factors on the health and productivity of commercial freshwater fish species.

In this study, serum lysozyme activity was studied by the agar well diffusion assay in various species of fish (common carp, Cyprinus carpio, pikeperch, Sander lucioperca, prussian carp, Carassius gibelio) and crayfish (Astacus leptodactylus) obtained from three different regions in spring and autumn in 2013. The highest levels of lysozyme activity were found in pikeperch fish, followed by common carp, prussian carp, and crayfish, respectively. There was no significant difference between common carp, prussian carp, and crayfish, but it was found a significant between pikeperch fish and the other species (p

Population structure of crucian carp in a small freshwater lake on Bolshoy Pelis Island is studied on the data of trap catches conducted in 1985, 1995 and 2015. Mature part of the population consisted of fish with length 110–280 mm TL and age from 2 to 8–9 years that are usual parameters for this species. Age was estimated using annuli on fish scale. The largest caught fish was the 14-years female with length 470 mm TL and weight 1650 g. All fish reached sexual maturity at age of 2 years. In the age of 5 years and more, the number of females in the population exceeded the number of males (2♀ : 1♂ in 1985). Length-weight relationship was calculated as W = a . TLb. Growth rate was calculated on length-at-age data. Rate of linear and weight growth of females was higher than males in 1985 and 2015 that is considered as a natural difference. After partial elimination of the population in 1995 under natural reasons (hypoxia and toxic microalgae bloom), growth rate of males and females became equal and number of males increased quickly, they were twice more numerous than females. However, the females prevailed again in the sex ratio in 2015. Rate of linear and weight growth was the lowest in 2015, probably because of high density of the fish population.

Increasing toxic metal content in aquatic products has become a universal burden due to the risks to aquatic organisms and human health associated with the consumption of these products. In this study, toxic metal distribution and accumulation in the organs of fish and bivalve species of economic and culinary importance from the lower reaches of the Yangtze River are examined, and the corresponding health risks are also investigated. In general, the viscera and gill show higher concentration of metals than other tissues. The order of the accumulation sequence of metals in muscle tissue of fish and bivalve is Zn > Cu > Mn > Cr > As > Hg > Pb > Cd and Mn > Zn > Cu > As > Cr > Pb > Cd > Hg respectively. Maximum accumulation of Mn (507.50 μg g−1) and Pb (0.51 μg g−1) in the gill tissues indicates the major uptake of these metals from the water column. According to the Hazard Index (HI) calculations (based on USEPA), the analyzed metals will not cause any harmful health effects to individuals for both normal and habitual fish consumers, except for Hg and As in habitual consumers, if these species are consumed at a larger amount. Compared to the Chinese Food Health Criterion and other international standards (WHO/FAO), metal concentrations in the edible muscle tissues of the studied species are lesser than the acceptable levels and found to be fit for human consumption.

The rate constants of 137Cs uptake in Prussian carp (Carassius gibelio) from the water with a potassium content of 2 mg·L-1 at T = 5 °C without feeding (kw = 0.045 ± 0.001 day-1), at T = 12 °C with «clean» feeding (0.046 ± 0.002 day-1) and at T = 22 °C with «clean» feeding (0.062 ± 0.006 day-1) were obtained in a series of aquarium experiments. The results showed that rates of 137Cs uptake in fish from water without and with feeding did not significantly differ at different temperatures of water (T = 5 - 22 °C) and were two orders of magnitude lower than the rate constants of 137Cs uptake in Prussian carp with feed in Chornobyl exclusion zone (11.4 ± 2.6 day-1). This makes it possible to obtain products with 137Cs content below the permissible level (150 Bq·kg-1) while providing fish with clean feeds even in the most radioactively contaminated reservoirs of the exclusion zone. A decrease in the potassium content in water from 2 to 0.2 mg·L-1 (no feeding, T = 5 ± 1 °C) resulted in an increase in the rate of 137Cs uptake into the fish from the water by 1.6 times. An increase in the potassium content in water by 10 times up to 20 mg L-1 resulted just in a decrease of 20 % in the rate. The levels of 137Cs activity concentration in fish in contaminated water at temperatures below 10 °C will be two orders of magnitude lower compared to radioactive contamination of water in the summer season (T = 22 °C). This is extremely important for the correct prediction of fish contamination in the autumn-winter-spring period at a water temperature of less than 10 °C when some fish stop feeding.

The fish species composition and structural characteristics of the ichthyofauna of the Lower Dniester and Dniesterovskiyliman are presented. In total 79 species of fish from 16 orders, 24 families, 61 genera were observed in 2006–2018.The largest number of species in two orders: Cypriniformes and Perciformes (40.5 and 25.3%, respectively); largest number of genera and species in families: Cyprinidae – 22 genera and 29 species, Gobiidae – 7 genera and 13 species,and Percidae – 5 genera and 5 species. Ichthyofauna of Lower Dniester and Dniesterovskiy liman is represented byfour main faunal complexes. The dominant complex is the Ponto-Caspian, combining brackish and marine fish species.Ichthyofauna of the Lower Dniester is formed mainly by freshwater (55.7% of the total number of identified species)and brackish-water fish (26.6%). Most of species (77.2%) are demersal and bottom dwelling, phytophiles (34.2%)and lithophiles (22.8%), benthophages and carnivores. The remaining groups are represented by fewer species.The analysis of the current state of aquatic bioresources are presented. From 16 to 28 species of fish are recorded inthe commercial catches of the Lower Dniester and Dniestrovskiy liman. The dynamics of catches of the main commercialfish species are presented according to official statistics. Significant increase in the catch of gibel carp, an increase inthe catch of common carp? roach and common bream, and a decrease in the number of populations of predatory fishspecies was observed. The total catch of aquatic biological resources from 2013 to 2017 increased sharply from 547.9 to2344.3 tons per year. Gibel carp Carassius gibelio (Bloch, 1782) is the dominant fish species in the Lower Dniester.The catches of this species increased significantly (up to 1967.8 tons). The age and sex composition, as well as the sizemasscharacteristics of the main commercial species are presented. A decrease in the age composition of the populationsof the main commercial fish species as a result of an increase in the intensity of fishing was observed. The commercialfish mortality rates and stocks of the main commercial species are presented. The stock of gibel carp is set at 5,000–6,000 tons, bream – 630 tons, roach – about 150-200 tons, common carp about 200–250 tons, pikeperch – 20–25 tons.Forecasts of the allowable catch of the main commercial fish species of the Lower Dniester are presented.

* Carassius auratus (Linnaeus, 1758). Goldfish; Carpa Dorada, Pez Chino. Distribution: Global: Asia; from central Asia and China to Japan, Pacific and Indian drainages; introduced throughout the world; Costa Rica: SC (Atlantic) and Ta (Pacific), 29���1779 m.a.s.l., Pri, Pot. Occurrence and conservation status: Exo, LC. References: Bănărescu & Paepke (2002: 185; detailed description, including illustrations, information on distribution and ecology), Banarescu & Paepke (2002: 5; detailed description, including illustrations, information on distribution and ecology) and Angulo et al. (2013: 991; listed, including taxonomic information and distributional data)., Published as part of Angulo, Arturo, 2021, New records and range extensions to the Costa Rican freshwater fish fauna, with an updated checklist, pp. 1-72 in Zootaxa 5083 (1) on page 23, DOI: 10.11646/zootaxa.5083.1.1, http://zenodo.org/record/5800630, {"references":["Banarescu, P. M. & Paepke, H. J. (2002) The freshwater fishes of Europe. Cyprinidae 2, Part III: Carassius to Cyprinus. Aula- Verlag, Wiesbaden, 305 pp."]}

The invasion success of gibel carp (Carassius gibelio) depends on demographic and competitive traits. The major biological trait responsible for the invasiveness of C. gibelio is the mode of reproduction. Apart from sexual reproduction, which is typical in fish, C. gibelio is a unique cyprinid species able to reproduce through asexual gynogenesis, which is also known as sperm-dependent parthenogenesis, observed in all-female populations. Though the sexual and asexual forms of C. gibelio co-exist widely in natural habitats, the gynogenetic form has the capacity to modulate the range of effective ecological niches, which may facilitate the process of invasion. In this paper, we reviewed current knowledge of the sexual and gynogenetic forms of gibel carp along with their physiological advantages, immunological traits, and ability to withstand different environmental conditions. As parasitic infection may directly alter the immunology of hosts, and also indirectly alter their investment in reproduction, we provide some insights into the role of parasites as one of the potential drivers facilitating the coexistence of asexual and sexual forms. We highlight evidence that gibel carp have been identified as a serious threat to native species; hence, its impact on the ecosystem is also discussed.

Three species of Carassius are considered to occur in the perialpine region: Carassius carassius (Crucian carp), C. gibelio (Prussian carp) and C. auratus (goldfish). According to the Ordinance of the Swiss Fisheries Act none of these species are native to Switzerland. C. auratus is native to East Asia and has been introduced throughout Europe and most of the world. The native distributions of C. carassius and C. gibelio are uncertain. C. carassius is believed to be native to eastern and central Europe, as far west as the Rhine [9]. C. gibelio may be native to the central European lowlands or introduced from Asia [9]. C. carassius can be identified by a convex rear edge of the dorsal fin and 31-36 scales along the lateral line, while the rear edge of the dorsal fin in the other two species is concave or straight and they have fewer scales along the lateral line (26-33). C. auratus and C. gibelio are distinguished by colour (golden-bronze and silvery brown, respectively). The three species are however often confused with one another. [9] [9] All Carassius caught in Projet Lac except some from Lake Garda, were C. gibelio. This species was recorded in all southern perialpine lakes, as well as lakes Rousses, Constance Upper and Morat in the north. In most cases, DNA barcoding was not able to distinguish whether these fish were C. gibelio or C. auratus (3 from Maggiore, 1 from Lugano, 2 from Constance Upper and 1 from Morat), but clearly ruled out any C. carassius. Barcoding did however confirm the presence of two individuals of Carassius auratus in Lake Garda., Published as part of Alexander, Timothy & Seehausen, Ole, 2021, Diversity, distribution and community composition of fish in perialpine lakes – " Projet Lac " synthesis report, Eawag: Swiss Federal Institute of Aquatic Science and Technology on page 118, DOI: 10.5281/zenodo.5779569

The increasing world market demand for seafood requires an expansion of product categories available to consumers. Inland fish are usually considered having unmarked taste and are less appreciated by consumers; thus, they have low commercial value. Therefore, the marketing of the lake’s fresh and processed fish is limited to the local market and consumers are currently uninformed and mistrustful about these species. In this study, six different fish species were caught in the Fondi lake (Lazio, central Italy): Anguilla anguilla, Tinca tinca, Carassius gibelio, Cyprinus carpio, Micropterus salmoides, Chelon ramada. All the samples were subjected to nutritional and DNA barcoding analysis. Moisture, protein, fat, carbohydrates, ash, and sodium content were measured. As regards the fatty acids profile, the most abundant were MUFAs with the highest value in Anguilla anguilla (45.97%). Oleic acid (C18: 1 n9 cis) was particularly high in Cyprinus carpio (55.46%). The fraction of polyunsaturated fatty acids (PUFA) revealed a higher DHA content (C22: 6 n3) in Anguilla anguilla than the other species (>12 %) while Chelon ramada presented both higher EPA content (C 20: 5 n3) and total fraction of omega 3 PUFAs. Concerning molecular analysis, a 655 bp fragment of cytochrome C oxidase subunit I (COI) gene was successfully used for the identification at the species level using both BOLD and BLAST public databases. The present study gives the basis for improving the knowledge and promoting inland fish’ market and traceability along the supply chain.

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 paper 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.

Polyploidy and subsequent diploidization provide genomic opportunities for evolutionary innovations and adaptation. The researches on duplicated gene evolutionary fates in recurrent polyploids have seriously lagged behind that in paleopolyploids with diploidized genomes. Moreover, the antiviral mechanisms of Viperin remain largely unclear in fish. Here, we elaborate the distinct antiviral mechanisms of two viperin homeologs (Cgviperin-A and Cgviperin-B) in auto-allo-hexaploid gibel carp (Carassius gibelio). First, Cgviperin-A and Cgviperin-B showed differential and biased expression patterns in gibel carp adult tissues. Subsequently, using co-immunoprecipitation (Co-IP) screening analysis, both CgViperin-A and CgViperin-B were found to interact with crucian carp (C. auratus) herpesvirus (CaHV) open reading frame 46 right (ORF46R) protein, a negative herpesvirus regulator of host interferon (IFN) production, and to promote the proteasomal degradation of ORF46R via decreasing K63-linked ubiquitination. Additionally, CgViperin-B also mediated ORF46R degradation through autophagosome pathway, which was absent in CgViperin-A. Moreover, we found that the N-terminal α-helix domain was necessary for the localization of CgViperin-A and CgViperin-B at the endoplasmic reticulum (ER), and the C-terminal domain of CgViperin-A and CgViperin-B was indispensable for the interaction with degradation of ORF46R. Therefore, the current findings clarify the divergent antiviral mechanisms of the duplicated viperin homeologs in a recurrent polyploid fish, which will shed light on the evolution of teleost duplicated genes.

Cyanobacteria are important members of lake plankton, but they have the ability to form blooms and produce cyanotoxins and thus cause a number of adverse effects. Freshwater ecosystems around the world have been investigated for the distribution of cyanobacteria and their toxins and the effects they have on the ecosystems. Similar research was performed on the Fehérvárcsurgó reservoir in Hungary during 2018. Cyanobacteria were present and blooming, and the highest abundance was recorded in July (2,822,000 cells/mL). The species present were Aphanizomenon flos-aquae, Microcystis flos-aquae, Microcystis wesenbergii, Cuspidothrix issatschenkoi, Dolichospermum flos-aquae, and Snowella litoralis. In July and September, the microcystin encoding gene mcyE and the saxitoxin encoding gene sxtG were amplified in the biomass samples. While a low concentration of microcystin-RR was found in one water sample from July, analyses of Abramis brama and Carassius gibelio caught from the reservoir did not show the presence of the investigated microcystins in the fish tissue. However, several histopathological changes, predominantly in gills and kidneys, were observed in the fish, and the damage was more severe during May and especially July, which coincides with the increase in cyanobacterial biomass during the summer months. Cyanobacteria may thus have adverse effects in this ecosystem.

The aim of this study was to investigate the bioaccumulation of cadmium in the muscle tissue of Prussian carp during 7 and 13 weeks of exposure to different concentrations of this metal in water (0.4 and 4.0 mg/L), and the depuration of cadmium from muscle during the following 6-week depuration period in the presence of melatonin implants. Furthermore, the relationship between cadmium accumulation and the levels of essential bioelements (copper, zinc, iron) in muscle was evaluated, as well as the bioconcentration factor of cadmium. Heavy metal concentration was determined using atomic absorption spectrometry. Cadmium accumulation in fish muscle increased with the duration of exposure. Cd concentrations exceeded the permissible levels for human consumption in groups exposed to the higher concentration of this metal. Moreover, a significant increase of Zn and Fe levels in the muscle was observed. In the fish that received melatonin implants and were exposed to Cd, its level in the muscle was significantly lower. The depuration of accumulated cadmium depended mainly on the duration of the elimination period. This is the first study to report that melatonin co-administration can effectively protect the fish from the accumulation of cadmium in muscle tissue and changes in trace metal levels.

The aim of the study was to investigate the accumulation of cadmium in the scales of Prussian carp (Carassius gibelio Bloch, 1782) as an indicator tissue of water contamination by cadmium. The study was carried out on 130 mature Prussian carp, which were placed in three 300L tanks. The fish were exposed to cadmium dissolved in water at a concentration of 0.0, 0.4 or 4.0 mg/L for a period of 84 days. After 42 and 84 days of exposure, 10 fish were randomly sampled from each tank. The fish were decapitated and all their scales were collected. The scales were rinsed and each of them was then carefully sectioned into an inner part and an outer part, removing the outermost growth ring, which most likely included scale increment from the exposure period. Cadmium concentration in the samples was then measured using the atomic absorption method. The analysis of the results showed that the concentration of cadmium in the scales increased with the duration of exposure and was significantly higher in the outer growth rings. The accumulation of cadmium in this part of the scales was correlated with the dose of cadmium and the duration of exposure. The results obtained confirmed the hypothesis that the concentration of cadmium in the outermost growth rings of fish scales reflects the most recent status of environmental contamination by this metal. Scales, which unlike other tissues such as the liver and muscle, can be sampled non-lethally, seem to be an excellent bioindicator of environmental contamination by heavy metals.