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Leuciscus idus (Linnaeus, 1758) [N]—Ide Taxonomy. Original description: Cyprinus idus Linnaeus, 1758: 324 [European freshwaters; no types known].— Afghanistan synonyms: Cyprinus idbarus Linnaeus, 1758; Cyprinus jeses Linnaeus, 1758; Leuciscus idus lapponicus Günther, 1868; Idus melanotus Heckel, 1843; Cyprinus microlepidotus Ekstr ̂m, 1835; Idus miniatus Bonaparte, 1845; Idus oxianus Kessler, 1877; Squalius oxianus Kessler, 1877; Idus miniatus Heckel & Kner, 1857; Leuciscus neglectus Selys-Longchamps, 1842.—Revisions: Berg (1949: 564).—Illustration: Berg (1949: 565, fig. 330). Status in Afghanistan. First record from Afghanistan by Berg (1949: 566); listed by Coad (1981: 11; 2015: 327) as possible species.—Afghanistan materials: None. Distribution and habitat. Distribution in Afghanistan: Amu Darya.—General distribution: Europe; widely introduced elsewhere.—Habitat: This species usually lives in large lowland rivers and nutrient-rich lakes. Migrates to tributaries for spawning in moderate current on gravel or submerged vegetation. Freshwater. Economic importance. Commercially important. Conservation. Conservation status in Afghanistan: Unknown.—IUCN: LC (Freyhof & Kottelat 2008d).—Threats: No major threats known.—Low sensitivity to human activities.—Not considered as a keystone species.— Decline status: Unknown.—Low priority for conservation action. Remarks. This species reported from lover Amu Darya. Therefore, presence of the species should be clarifying by field sample., 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 pages 35-36, 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.","Gunther, A. (1868) Catalogue of the fishes in the British Museum. Catalogue of the Physostomi, containing the families Heteropygii, Cyprinidae, Gonorhynchiidae, Hypodontidae, Osteoglossidae, Clupeidae, Chirocentridae, Alepochephalidae, Notopteridae, Halosauridae, in the collection of the British Museum. Vol. 7. Department of Zoology, British Museum (Natural History), London, xx + 512 pp.","Kessler, K. F. (1877) The Aralo-Caspian Expedition. IV. Fishes of the Aralo-Caspio-Pontine ichthyological region. Aralo-Caspian Expedition, St. Petersburg, xxviii + 360 pp., pls. 1 - 8.","Berg, L. S. (1949) s. n. In: Ryby presnych vod SSSR i sopredelnych stan. [Freshwater fishes of the U. S. S. R. and adjacent countries]. Vol. 2. 4 th Edition. Opredeliteli po faune SSSR. [Guide to the Fauna of the U. S. S. R.], Moskva. Freshwater fishes of the U. S. S. R. and adjacent countries No. 29. Russian Academy of Sciences, USSR, Moskva, pp. 467 - 925. [in Russian, English translation appeared in Israel Program of Scientific Translation, Jerusalem, 1964, 496 pp.]","Coad, B. W. (1981) Fishes of Afghanistan, an annoted checklist. National Museum of Canada Publications in Zoology, 14, i - v + 1 - 26.","Freyhof, J. & Kottelat, M. (2008 d) Leuciscus idus. The IUCN Red List of Threatened Species, 2008, e. T 11884 A 3312021. https: // doi. org / 10.2305 / IUCN. UK. 2008. RLTS. T 11884 A 3312021. en"]}

Leuciscus lehmanni Brandt, 1852 [N]—Zeravshan dace Taxonomy. Original description: Leuciscus lehmanni Brandt, 1852: 339 [Samarkand, Uzbekistan; holotype: GCM F 9].— Afghanistan synonyms: Leuciscus angrenicus Serov, 1941; Squalius intermedius Kessler, 1872.— Revisions: Berg (1949: 548).—Illustration: Berg (1949: 548, figs. 314–315). Status in Afghanistan. First record from Afghanistan by Berg (1949: 549); listed by Coad (1981: 11; 2014: 182; 2015: 228) as possible distributed species.—Afghanistan materials: None. Distribution and habitat. Distribution in Afghanistan: Amu Darya.—General distribution: Aral Sea system.— Habitat: This species is found near the surface of open waters in large rivers and lakes. Semi-anadromous individuals forage and spawn in pelagic environments. Lacustrine populations spawn in open water in lakes. Freshwater. Economic importance. Commercially important. Conservation. Conservation status in Afghanistan: Unknown.—IUCN: LC (Karimov & Mamilov 2020b).—Threats: No major threats known.—Low sensitivity to human activities.—Not considered as a keystone species.— Decline status: Unknown.—Low priority for conservation action., 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 36, DOI: 10.11646/zootaxa.5305.1.1, http://zenodo.org/record/8048564, {"references":["Kessler, K. F. (1872) Ichthyological Fauna of Turkestan. Izvestiia Imperatorskago Obschchestva Liubitelei Estestvozaniia, Antropologii i Etnografii, 10 (1), 47 - 76, pls. 6 - 12.","Berg, L. S. (1949) s. n. In: Ryby presnych vod SSSR i sopredelnych stan. [Freshwater fishes of the U. S. S. R. and adjacent countries]. Vol. 2. 4 th Edition. Opredeliteli po faune SSSR. [Guide to the Fauna of the U. S. S. R.], Moskva. Freshwater fishes of the U. S. S. R. and adjacent countries No. 29. Russian Academy of Sciences, USSR, Moskva, pp. 467 - 925. [in Russian, English translation appeared in Israel Program of Scientific Translation, Jerusalem, 1964, 496 pp.]","Coad, B. W. (1981) Fishes of Afghanistan, an annoted checklist. National Museum of Canada Publications in Zoology, 14, i - v + 1 - 26.","Coad, B. W. (2014) Fishes of Afghanistan. Pensoft Publishers, Sofia-Moscow. 393 pp.","Mamilov, N. & Karimov, B. (2020 b) Capoetobrama kuschakewitschi. The IUCN Red List of Threatened Species, 2020, e. T 169620 A 156732450. https: // doi. org / 10.2305 / IUCN. UK. 2020 - 3. RLTS. T 169620 A 156732450. en"]}

Leuciscus aspius (Linnaeus, 1758) [N]—Asp Taxonomy. Original description: Cyprinus aspius Linnaeus, 1758: 325 [Swedish lakes; no types known]— Afghanistan synonyms: Aspius aspius (Linnaeus, 1758).—Revisions: Berg (1949: 603) as Aspius aspius.— Illustration: Berg (1949: 604, figs. 357–359) as Aspius aspius. Status in Afghanistan. First record from Afghanistan by Berg (1949: 605) as Aspius aspius; confirmed by Coad (1981: 9 as Aspius aspius; 2014: 179; 2015: 228).—Afghanistan materials: None. Distribution and habitat. Distribution in Afghanistan: Amu Darya.—General distribution: Asia: Distribution: Europe to western Asia.—Habitat: This species is found in open water in large and mid-sized lowland rivers and large lakes. Spawns on gravel or submerged vegetation in fast-flowing water. Lake populations migrate to tributaries. Freshwater, brackish. Economic importance. Commercially important. Conservation. Conservation status in Afghanistan: Unknown.—IUCN: LC (Freyhof & Kottelat 2018).—Threats: CON, ABS, HAB.—Low sensitivity to human activities.—Keystone species.—Decline status: Unknown.— Low priority for conservation action., 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 35, 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.","Berg, L. S. (1949) s. n. In: Ryby presnych vod SSSR i sopredelnych stan. [Freshwater fishes of the U. S. S. R. and adjacent countries]. Vol. 2. 4 th Edition. Opredeliteli po faune SSSR. [Guide to the Fauna of the U. S. S. R.], Moskva. Freshwater fishes of the U. S. S. R. and adjacent countries No. 29. Russian Academy of Sciences, USSR, Moskva, pp. 467 - 925. [in Russian, English translation appeared in Israel Program of Scientific Translation, Jerusalem, 1964, 496 pp.]","Coad, B. W. (1981) Fishes of Afghanistan, an annoted checklist. National Museum of Canada Publications in Zoology, 14, i - v + 1 - 26.","Freyhof, J. & Kottelat, M. (2018) Leuciscus aspius (amended version of 2008 assessment). The IUCN Red List of Threatened Species, 2018, e. T 2178 A 136077402. https: // doi. org / 10.2305 / IUCN. UK. 2008. RLTS. T 2178 A 136077402. en"]}

Leuciscus leuciscus (Linnaeus, 1758) Remarks. This species was identified as being from Central Europe. Afghanistan is not included in the natural distribution range of the species. Previously, generally, specimens belonged to the genus Leuciscus, which was generally erroneously identified as Leuciscus leuciscus., 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 53, 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."]}

Inroduction. Changes in the species composition and population size of freshwater fihes are determined by deformations of the habitat in Ukraine and are characterized by a pronounced negative dynamics. Deformation of ichthyofauna is caused by extinction of a number of aboriginal fihes and emergence of alien species.Aim. To establish the current species composition and relative population size of fih species in the Oster River and the dynamics of these characteristics over a 50-yearlong period in the context of negative transformations of the ichthyofauna of the rivers of Ukraine.Results. Comparative study of the species composition and relative population size of fih species in the fih catches by small-river fihing gear in the Oster river was conducted during the period since 1971-72 till 2019. During this time considerable changes in species composition took place. The following species disappeared from the catches: Leuciscus leuciscus, Leuciscus idus, Chondrostoma nasus, Carassius carassius, Blicca bojerkna and Neogobius flviatilis, they were replaced by three invasion species (Percottus glenni, Pseudorasbora parva, Proterorhinus marmoratus). The changes in the dominant species took place, thus, in the Oster ichthyocene the species with the short life cycle started to prevail, the share of invasion species increased from 1.4 to 37%, and the share of initial marine fih among them is very low. The comparison with the river systems of the Stugna and the Lower Dnipro represents the fact that the mentioned negative tendencies are common for the whole Dnipro system, however the situation in the Lower Dnipro must be considered less critical than in the Oster and the Stugna rivers. The fact that the catches of industrial fih decreased more than 10 times in the Desna river during this period of time gives the reason to consider that the dramatic reduction of the absolute number of their populations occurred in the Oster river as well. That is why even relatively safe species (Abramis brama, Rutilus ritilus, Scardinius erythrophthalmus, Esox lucius, Perca flviatilis, Alburnus alburnus, Squalius cephalus) are in critical situation in this transformed river system.Сonclusions. In the ichthyocene of the Oster River over a 50-year period there have been signifiant changes in species composition, relative and absolute population numbers associated with the extinction and reduction of population sizes of rheophilic species and fih that are adapted to life in the flodplain. The modern Oster River is dominated by invasive and short-cycle species. The obtained tendencies in the dynamics of the ichthyofauna of the Oster River are similar to the nature of changes in other river systems of Ukraine, although they occur at a faster pace, which is characteristic of the smallest plain rivers.

Leuciscus is a genus of fish belonging to subfamily Leuciscinae. While, it is widely distributed throughout Eurasia, our perception of the phylogenetic relationships among its members is mainly bas...

Amur ide (Leuciscus waleckii), a Cyprinid species, is broadly distributed in Northeast Asia. Different from its freshwater counterparts, the population in Lake Dali Nor has a strong alkalinity tolerance and can adapt to extremely alkali–saline water with bicarbonate over 50 mmol/L. To uncover the genetic basis of its alkaline adaptation, three populations, including one alkali form from Lake Dali Nor (DL), one freshwater form from its adjacent sister Lake Ganggeng Nor (GG), and one freshwater form from its historical origin, namely, the Songhua River (SH), were analyzed using genome resequencing technology. A total of 679.82 Gb clean data and 38,091,163 high-quality single-nucleotide polymorphism (SNP) loci were detected in the three populations. Nucleotide diversity and population structure analysis revealed that the DL and GG populations have lower nucleotide diversities and different genetic structures than those of the SH population. Selective sweeping showed 21 genes involved in osmoregulatory regulation (DLG1, VIPR1, AKT1, and GNAI1), inflammation and immune responses (DLG1, BRINP1, CTSL, TRAF6, AKT1, STAT3, GNAI1, SEC22b, and PSME4b), and cardiorespiratory development (TRAF6, PSME4b, STAT3, AKT1, and COL9A1) to be associated with alkaline adaption of the DL population. Interestingly, selective pressure (CodeML, MEME, and FEL) methods identified two functional codon sites of VIPR1 to be under positive selection in the DL population. The subsequent 3D protein modeling confirmed that these selected sites will incur changes in protein structure and function in the DL population. In brief, this study provides molecular evidence of population divergence and alkaline adaptation, which will be very useful for revealing the genetic basis of alkaline adaptation in Amur ide.

Spawning strategies of lowland river fishes include single spawning, where reproduction generally occurs in early spring to provide 0+ fish with an extended growth season through the summer, but with a high risk of stochastic mortality events occurring, such as early summer floods. This risk can be reduced by multiple or protracted spawning strategies, where 0+ fish are produced over an extended period, often into mid-summer, but with the trade-off being a shorter growth season. The spawning strategies of cypriniform fish were explored in the River Teme, a spate river in Western England, which has non-indigenous European barbel Barbus barbus present. Sampling 0+ fish in spring and summer and across three spawning periods, B. barbus, chub Squalius cephalus and minnow Phoxinus phoxinus always revealed multiple spawning events, with 0+ fish of < 20 mm present in samples collected from June to August. Fish below 20 mm in August remained relatively small by the end of their growth season (October). For dace Leuciscus leuciscus, only single spawning events were evident, but with 0+ dace always being relatively large. Therefore, multiple spawning appears to be a common strategy that provides resilience in 0+ fish against stochastic mortality events in lowland rivers.

Invasive species tend to acquire native parasites from their invaded range over time. In these cases, native host-parasite dynamics may be altered as a result of differences in parasite population biology and host competency between invasive and native hosts. Competent invasive hosts are likely to increase transmission to native hosts while incompetent invasive hosts may dilute infection in natives. In this study, we used a freshwater fish system and a survey approach to compare the host competency and population biology of a dominant helminth parasite, Pomphorhynchus tereticollis, between native brown trout (Salmo trutta) hosts and invasive dace (Leuciscus leuciscus) hosts over 2 years at the core and edge of dace’s invasive range in Ireland. Our results show that, although dace acquired P. tereticollis, dace had prevalent and high intensity infections of immature extra-intestinal worms while prevalence of adult worms was consistently higher in brown trout. The majority of parasite individuals infecting dace were immature extra-intestinal forms and, in contrast to brown trout, parasites in dace did not attain sexual maturity. In addition, brown trout from the invasion core where dace have been established the longest had a lower abundance of P. tereticollis, indicating that by taking up but not transmitting infective stages of the parasite, invasive dace may dilute P. tereticollis infection in the native host.

Amur ide (Leuciscus waleckii, Family Cyprinidae) is widely distributed in Northeast Asia. L. waleckii usually inhabits freshwater environments but can also survive in the Lake Dali Nur, one of the most extreme aquatic environments on the earth, with an alkalinity up to 50 mmol/L (pH 9.6). To investigate mechanisms of mitogenomic evolution underlying adaptation to extreme environments, we determined 30 complete mitogenomes that included Lake Dali Nur (alkaline environment, AL) population and Amur basin (freshwater environment, FW) population. Through phylogenetic and divergence time analysis, we found that AL and FW populations forming distinct two groups which were consistent with geographic divergence (the formation of Lake Dali Nur). In addition, we found that almost of the windows exhibited higher nucleotide diversity in FW population (avg 0.0046) than AL population (avg 0.0012). This result indicated that severe environment selection had remarkably reduced the genetic diversity of mitogenome in AL population and suggested that severe environment selection had remarkably reduced the genetic diversity of mitogenome in the AL population. Compared with the FW population (ω = 0.064), the AL population (ω = 0.092) had a larger mean ω (dN/dS ratios) value for the 13 concatenated mitochondrial protein-coding genes, indicating that the high alkaline tolerated group had accumulated more nonsynonymous mutations. These nonsynonymous mutations had resulted in slightly beneficial amino acid changes that allowed adaption to the severe conditions. This study provides an additional view to decipher the adaptive mitogenome evolution of L. waleckii of the high alkaline environment.

The Far East Asian dace and minnow clade Pseudaspininae of Leuciscidae sensu stricto, as recognized by molecular phylogeny, comprises three genera, viz. Oreoleuciscus, Rhynchocypris (removed from Phoxinus), and Pseudaspius (including hitherto Tribolodon spp.). Descriptions of Rhynchocypris and Pseudaspius are revised following comparison with Oreoleuciscus as well as with two Eurasian genera Leuciscus and Phoxinus. Eurasian Leuciscus is distinguished from the other genera by having fewer than 60 longitudinal scales and Phoxinus by having a comb-like scale patch between the pectoral fin and opercle. Far East Asian Oreoleuciscus is unique in having a single pharyngeal teeth row, Rhynchocypris in having the anal fin base originating under the posterior end of the dorsal fin base, and Pseudaspius in having axillary scales on pelvic fin base.

Leuciscus waleckii is a freshwater fish that is known to inhabit the Dali Nor Lake, Inner Mongolia, China. The water in this lake has an HCO3–/CO32– concentration of 54 mM (pH 9.6) and a salinity of 0.6‰. The physiological mechanisms that allow this fish to tolerate these saline/alkaline conditions have yet to be elucidated. Transcriptional component analysis has shown that the expression levels of a large number of genes involved in the pathways responsible for osmo-ionoregulation and arachidonic acid metabolism pathway expression change significantly (p < 0.05) during the regulation of acid–base balance under high alkaline stress. In this study, we investigated the role of long non-coding RNAs (lncRNAs) during adaptation to high alkaline conditions. Fish were challenged to an NaHCO3-adjusted alkalinity of 0 mM, 30 mM (pH 9.44 ± 0.08), and 50 mM (pH 9.55 ± 0.06) for 20 days in the laboratory. Gill and kidney tissues were then collected for high-throughput sequencing assays. A total of 159 million clean reads were obtained by high-throughput sequencing, and 41,248 lncRNA transcripts were identified. Of these, the mean number of exons and the mean length of the lncRNA transcripts were 4.8 and 2,079 bp, respectively. Based on the analysis of differential lncRNA transcript expression, a total of 5,244 and 6,571 lncRNA transcripts were found to be differentially expressed in the gills and kidneys, respectively. Results derived from Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) analysis of the coding genes were correlated with the lncRNA expression profiles. GO analysis showed that many lncRNAs were enriched in the following processes: “transporter activity,” “response to stimulus,” and “binding.” KEGG analysis further revealed that metabolic pathways were significantly enriched. A random selection of 16 lncRNA transcripts was tested by RT-qPCR; these results were consistent with our sequencing results. We found that a large number of genes, with the same expression profiles as those with differentially expressed lncRNAs, were associated with the regulation of acid–base balance, ion transport, and the excretion of ammonia and nitrogen. Collectively, our data indicate that lncRNA-regulated gene expression plays an important role in the process of adaptation to high alkaline conditions in L. waleckii.

This paper reports the detection of the myxozoan species Myxobolus elegans Kashkovsky 1966 in common dace (Leuciscus leuciscus) that has not been previously listed as its host. The problem of differentiation of phenotypically similar Myxobolus species is addressed. During parasitological survey of common dace from the desalinated part of the Gulf of Finland at the city of Sestroretsk, Russia, numerous oval-shaped plasmodia, 0.2–0.4 mm in size, filled with Myxobolus spores were found on the gills. Pear-shaped myxospores were 15.4 (14.8–16.0) × 10.2 (9.6–10.9) µm in size with a rib on each valve. On the basis of spore morphology, the species appeared to be similar to M. elegans and Myxobolus hungaricus Jaczó, 1940. In order to identify the species, molecular genetic analysis was performed, and the species was identified on the basis of morphological characteristics and 18S rDNA data. The results obtained indicate that the Myxobolus species observed on the gills of dace is M. elegans. Thus, common dace is another valid host of M. elegans besides the type host, ide (Leuciscus idus).

This study aims to determine the endoparasitic fauna of the fish species caught in Menzelet Dam Lake in Kahramanmaras, Turkey. Cyprinus carpio, Barbus rajanorum, Alburnus sp., Capoeta angorae , Capoeta barroisi, Leuciscus cephalus and Luciobarbus pectoralis caught in the Dam Lake were examined in terms of internal parasites. Neoechinorhynchus rutili and Ligula intestinalis endoparasites were found. Parasites were stained, and pictures were taken under a microscope. The distribution of parasites is presented according to ecological terms.

The fish meat is an essential part of human diet. However, fish may be contaminated with different microorganisms, including pathogens. Antimicrobial resistance of fish microbiota may facilitate the spread of resistant microorganisms causing serious consequences for human health. The aim of the present study was to detect bacterial contamination in fish gill, gut and skin and to determine antimicrobial susceptibility of the bacterial isolates. Rainbow trout (Oncorhynchus mykiss) and bream (Abramis bram) were obtained from the market in Jelgava city. Chub (Leuciscus cephalus), crucian carp (Carassius carassius) and tench (Tinca tinca) were collected from fishermen. Fish samples were examined for the total bacterial count (TBC), coliforms, Enterobacteriaceae, Pseudomonas spp. and Aeromonas spp. Testing was done in accordance with International Organization for Standardization (ISO) standards. Identification of all bacteria was accomplished with the Matrix Assisted Laser Desorption Ionization – Time of Flight Mass Spectrometry (MALDI-TOF MS) method. The disc diffusion method was used for the detection of antibiotic susceptibility of isolated bacterial species. TBC ranged from 2.70 to 7.00 log CFU.g-1, coliforms from 0 to 2.67 log CFU.g-1, Enterobacteriaceae from 0 to 2.85 log CFU.g-1. The highest contamination with Pseudomonas spp. and Aeromonas spp. was observed in chub gut samples with 1.60 log CFU.g-1 and 2.23 log CFU.g-1, respectively. Altogether, 16 microbial genera and 31 bacterial species were identified. The dominant bacterial species belonged to Pseudomonas spp. (54%) and Enterobacteriaceae. Pseudomonas spp. were resistant to ticarcillin, susceptibility to ciprofloxacin showed 88% of isolates. All Enterobacteriaceae isolates were susceptible to imipenem. The microbial quality of the fish was acceptable, but the presence of antibiotic resistant bacteria may further cause a negative impact on public health.

This study focused on the artificial reproduction of common dace Leuciscus leuciscus (L.) outside the reproductive season. The results indicate there is the possibility of initiating the reproducion in individuals of this before the natural spawning season. There could be induction of spermiation by altering the environmental conditions. For females, hormonal injections were necessary for induction of final oocyte maturation and ovulation. Generally, there were high percentages of spermiation (100%) and ovulation (87%–100%) as well as low mortality (0%–11% and 7%–13% for males and females, respectively) among the induced spawners. The greatest embryo survival occurred when Ovaprim (84.4%) or hCG (89.6%) was administered, although the latency time using hCG was at least twice as long compared to when other spawning agents were used (84–92 hrs and 30–44 hrs). The results from present study could be applicable for optimization of breeding stock numbers in aquaculture enterprises and in providing insights for conservation of L. leuciscus endangered populations.

Infection with the liver fluke, Opisthorchis felineus, caused by the consumption of infected raw or undercooked cyprinid fish is common in humans and carnivores in the middle Ob River basin (Tomsk region, Russia) and can lead to diseases in humans. The goal of this study was the status of fish infection with O. felineus metacercariae in order to assess the role of fish in the infection of the human population in the middle Ob River basin. Of the 14 Cyprinidae species recorded in the middle Ob River basin, we examined 6 cyprinid species for prevalence and intensity of infection with O. felineus metacercariae. Five of these species (Leuciscus idus, Leuciscus leuciscus, Rutilus rutilus, Abramis brama, and Carassius gibelio) are of commercial value, while the common bleak is an object of amateur fishing. In addition, we conducted a survey of the fish consumption habits as part of a community-based cross-sectional study in the rural Shegarsky district, Tomsk region, Russian Federation. O. felineus metacercariae were observed in muscles of all examined species except for the Prussian carp. The ide is the main infection source in the Ob River (prevalence of infection, 100%, and intensity, 50.5 metacercariae per fish) and the common dace in the Tom River (91.1% and 12.7 metacercariae). Although the two alien species (bream and common bleak) are susceptible to infection with O. felineus metacercariae, the prevalence of infection in these fish and in the roach did not exceed 3%. The prevalence and intensity of infection in fish increased with age and size. The infection characteristics of fish in different water flows were different. The cyprinid species account on average for 69.8% of the commercial fish harvested in the Tomsk region. According to epidemiological survey, among 600 participants, 87.5% (n = 525) of respondents consumed river fish, with the most popular fish being cyprinids including Prussian carp, dace, ide and bream, followed by pike and perch. Thus, the epizootological state of the water flows in the middle Ob River basin is adverse with respect to opisthorchiasis, as indicated by high infection rates of liver fluke metacercariae in ide and common dace, which are abundant species of high commercial value. An extremely high prevalence of infection suggests a strong transmission cycle with a high rate of infection from infected humans and/or animal reservoir hosts to snails and fish. In addition to treating humans, there should be a strong focus on identifying these potential reservoir hosts to reduce subsequent infection in humans. Furthermore, since the intensity of infection in humans is determined by the presence of fish species such as ide and dace in the diet, they should be included in a dietary change campaign by eliminating the consumption of raw fish., Highlights • Commercial cyprinid species play the key role in maintaining opisthorchiasis foci. • The ide and common dace are the main source of human and animal infection. • Measures to control Opisthorchis felineus should target these two species of fish. • The invasion of fish increases with their age and size.

The meso-scale habitat simulation model MesoHABSIM was applied in three Lithuanian lowland rivers to study the effect of low-head hydropower plants (HPPs) on the fish habitats. Stream flow time series on a daily scale for the period 1970–2015 were used to describe flow regime downstream of HPPs for periods before and after their installation. Conditional habitat suitability criteria were developed for 4 species of cyprinid fish, schneider (Alburnoides bipunctatus), dace (Leuciscus leuciscus), roach (Rutilus rutilus) and vimba (Vimba vimba) to simulate their available habitat at different water discharges. Modelling results showed that HPPs have a significant impact on habitat availability in the low flow period in dry years below HPPs due to insufficient released flow. The environmental flow, as prescribed by the Lithuanian national law, is estimated between 80 and 95% exceedance probability of the mean minimum discharge of 30 days. This flow leads to a significant reduction in frequency and duration of available suitable habitats for vimba and schneider during low flow period. The roach habitat is the least affected. The results of habitat modelling are in line with the actual data on the occurrence and relative abundance of considered fish species in the studied river stretches. A general comparison of the relative abundance of modelled fish species in 42 natural river stretches and 20 stretches below the HPPs also showed that the relative abundance of roach is significantly higher, and that of schneider is significantly lower in river sections below the HPPs than the abundance in natural river sections. All results indicate that the current environmental flow does not secure survival of certain fish species. The applicability of the average low flow release during summer could be a plausible alternative to the current environmental flow in order to maintain ecosystem health and services.

Determining where fish are distributed across days and seasons is valuable for understanding their ecology, evolution and conservation. The results presented here provide insight into the spatial and temporal distribution of brown trout (native salmonid species) and dace (invasive cyprinid species) in an artificially impounded section of lowland river, demonstrating that both species remain relatively local to their release point and do not exhibit wide-ranging movements from late summer into winter. Commonalities in the movement patterns were observed between the species despite their contrasting life histories, but there were also important differences observed both in their home range and activity patterns over the duration of the study. In general dace were much more active than trout. Both trout and dace exhibited clear crepuscular peaks in movement with higher displacement rates being observed during dawn and dusk periods which remained consistent over the duration of the study. Both species exhibited a high residency which may be a direct result of the artificial barrier present, promoting residency. Trout showed a significant increase in displacement rates and a drop in residency in November which may represent putative spawning behaviour. In general home range sizes remained stable over the tracking period for both species. Home range size was affected by fish length for both species, with larger individuals being more localised then smaller individuals. We propose that the diel patterns observed are primarily driven by foraging activity and opportunity which changes with seasonal influences and onset of potential spawning period and/or overwintering behaviour. This study demonstrates how data derived from telemetry studies can reveal movement behaviours of fish species associated with undertaking basic ecological requirements (feeding, shelter etc.) which are regulated by variation in the environment. Understanding the interplay between the environment and an animal’s behaviour is important from a conservation management perspective with increasing environmental pressures and predicted regime changes. From a fishery management viewpoint these data can feed into stock status monitoring in difficult to monitor impounded lowland riverine habitat and also increase our understanding of how potential human induced changes affect fish populations.

Two novel myxosporeans have been identified during the present study namely, Myxobolus upmae sp. nov. infecting gills of Hypophthalmichthys nobilis and Myxobolus hardevi sp. nov. infecting gills of Labeo bata inhabiting Ranjit Sagar Wetland, Punjab (India). The identification was done on the basis of morphological and molecular attributes of the myxospores. Myxospores of both the species possessed distinct morphological and morphometric characteristics, hence, validated as new species. Prevalence of infection was found to be 31.25% and 24% in M. upmae and M. hardevi, respectively. The intensity of infection or the mean abundance was determined by the gill plasmodial index (GPI) and was found to be 3 in M. upmae (heavy infection) and 1 in M. hardevi (light infection). Histopathological analysis of both the myxosporeans showed necrosis, hypertrophy, lamellar fusion and the cavity of each plasmodium was filled with numerous fully mature myxospores. The phylogenetic analysis of M. upmae sp. nov. showed maximum homogeneity with M. catlae (KM029967) infecting gills of Catla catla from India followed by M. dujardini (DQ439804) infecting gills of Leuciscus cephalus from Hungary and M. alvarezae (FJ716096) infecting gills of Aspius aspius from Hungary. The phylogenetic tree obtained by Maximum-Likelihood showed the paraphyletic nature of M. upmae sp. nov. with other myxosporean species.

Contracaecum rudolphii (s. l.) is a complex of sibling species of anisakid nematodes having the fish-eating birds belonging to the Family Phalacrocoracidae as final hosts. The great cormorant Phalacrocorax carbo sinensis is parasitized by C. rudolphii A and C. rudolphii B. Adults and L4 specimens of C. rudolphii (s. l.) (N = 3282) were collected in cormorants from brackish and freshwater ecosystems of Central Italy. Third-stage larvae of Contracaecum (N = 882) were obtained from the fish species Dicentrarchus labrax, Anguilla anguilla, Aphanius fasciatus, Atherina boyeri, Leuciscus cephalus, Barbus barbus, and Carassius carassius captured in the same geographical areas of cormorants’ standings. Contracaecum rudolphii A and C. rudolphii B were identified by a multilocus genetic approach: allozymes, sequences analysis of the mtDNA cox2, and ITS region of rDNA gene loci. Differential distribution of the two parasite species was observed in different aquatic environments. Contracaecum rudolphii B outnumbered C. rudolphii A in wintering cormorants from freshwater ecosystems; the opposite trend was found in cormorants from brackish water. Analogously, C. rudolphii A larvae were more prevalent in brackish water fish, while C. rudolphii B larvae were found infecting only freshwater fish. The findings seem to confirm that C. rudolphii A and C. rudolphii B would have a life-cycle adapted to brackish and freshwater environments, respectively. A differential feeding behavior of wintering cormorants, the ecology of the infected fish species, and abiotic factors related to early stages of the parasites are supposed to maintain the distinctiveness of the two parasite species’ life cycles in the two different aquatic ecosystems.

Invasive species lose parasites in the process of invasion and tend to be less parasitized than conspecifics in the native range and sympatric native species in the invasive range (enemy release). We evaluated enemy release in an invasive freshwater fish in Ireland, common daceLeuciscus leuciscus, using helminth parasite community surveys at the core and front of the invasive range of common dace. Furthermore, we undertook a systematic literature review of helminth infection in common dace across its native range in Great Britain and Europe and invasive range in Ireland. The helminth parasite community survey revealed that invasive common dace were infected with fewer helminth species at the invasion front than at the core. Four helminth taxa – Acanthocephala, Monogenea, Digenea and Nematoda – were present in dace at the invasion core compared to only a single helminth species (Pomphorhynchus tereticollis) at the front. The systematic review revealed that invasive common dace in Ireland hosted fewer species of helminths than common dace in the native range. We report a total of three helminth species in common dace in Ireland compared to 24 in Great Britain and 84 in Continental Europe. Our results support the hypotheses that invasive populations are less parasitized than native populations and that more recently established populations host fewer parasites. However, we demonstrate that invasive species may continue to experience release from parasites long after initial invasion.